research papers about drinking water

Drinking Water Quality and Public Health

• Exposure and Health 11(4):1-7

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Article Contents

Introduction, physiological effects of dehydration, hydration and chronic diseases, water consumption and requirements and relationships to total energy intake, water requirements: evaluation of the adequacy of water intake, acknowledgments, water, hydration, and health.

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Barry M Popkin, Kristen E D'Anci, Irwin H Rosenberg, Water, hydration, and health, Nutrition Reviews , Volume 68, Issue 8, 1 August 2010, Pages 439–458, https://doi.org/10.1111/j.1753-4887.2010.00304.x

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This review examines the current knowledge of water intake as it pertains to human health, including overall patterns of intake and some factors linked with intake, the complex mechanisms behind water homeostasis, and the effects of variation in water intake on health and energy intake, weight, and human performance and functioning. Water represents a critical nutrient, the absence of which will be lethal within days. Water's importance for the prevention of nutrition-related noncommunicable diseases has received more attention recently because of the shift toward consumption of large proportions of fluids as caloric beverages. Despite this focus, there are major gaps in knowledge related to the measurement of total fluid intake and hydration status at the population level; there are also few longer-term systematic interventions and no published randomized, controlled longer-term trials. This review provides suggestions for ways to examine water requirements and encourages more dialogue on this important topic.

Water is essential for life. From the time that primeval species ventured from the oceans to live on land, a major key to survival has been the prevention of dehydration. The critical adaptations cross an array of species, including man. Without water, humans can survive only for days. Water comprises from 75% body weight in infants to 55% in the elderly and is essential for cellular homeostasis and life. 1 Nevertheless, there are many unanswered questions about this most essential component of our body and our diet. This review attempts to provide some sense of our current knowledge of water, including overall patterns of intake and some factors linked with intake, the complex mechanisms behind water homeostasis, the effects of variation in water intake on health and energy intake, weight, and human performance and functioning.

Recent statements on water requirements have been based on retrospective recall of water intake from food and beverages among healthy, noninstitutionalized individuals. Provided here are examples of water intake assessment in populations to clarify the need for experimental studies. Beyond these circumstances of dehydration, it is not fully understood how hydration affects health and well-being, even the impact of water intakes on chronic diseases. Recently, Jéquier and Constant 2 addressed this question based on human physiology, but more knowledge is required about the extent to which water intake might be important for disease prevention and health promotion.

As noted later in the text, few countries have developed water requirements and those that exist are based on weak population-level measures of water intake and urine osmolality. 3 , 4 The European Food Safety Authority (EFSA) was recently asked to revise existing recommended intakes of essential substances with a physiological effect, including water since this nutrient is essential for life and health. 5

The US Dietary Recommendations for water are based on median water intakes with no use of measurements of the dehydration status of the population to assist. One-time collection of blood samples for the analysis of serum osmolality has been used by the National Health and Nutrition Examination Survey program. At the population level, there is no accepted method of assessing hydration status, and one measure some scholars use, hypertonicity, is not even linked with hydration in the same direction for all age groups. 6 Urine indices are used often but these reflect the recent volume of fluid consumed rather than a state of hydration. 7 Many scholars use urine osmolality to measure recent hydration status. 8 , – 12 Deuterium dilution techniques (isotopic dilution with D 2 O, or deuterium oxide) allow measurement of total body water but not water balance status. 13 Currently, there are no completely adequate biomarkers to measure hydration status at the population level.

In discussing water, the focus is first and foremost on all types of water, whether it be soft or hard, spring or well, carbonated or distilled. Furthermore, water is not only consumed directly as a beverage; it is also obtained from food and to a very small extent from oxidation of macronutrients (metabolic water). The proportion of water that comes from beverages and food varies according to the proportion of fruits and vegetables in the diet. The ranges of water content in various foods are presented in Table 1 . In the United States it is estimated that about 22% of water intake comes from food while the percentages are much higher in European countries, particularly a country like Greece with its higher intake of fruits and vegetables, or in South Korea. 3 , – 15 The only in-depth study performed in the United States of water use and water intrinsic to food found a 20.7% contribution from food water; 16 , 17 however, as shown below, this research was dependent on poor overall assessment of water intake.

Ranges of water content for selected foods.

Data from the USDA national nutrient database for standard reference, release 21, as provided in Altman. 126

This review considers water requirements in the context of recent efforts to assess water intake in US populations. The relationship between water and calorie intake is explored both for insights into the possible displacement of calories from sweetened beverages by water and to examine the possibility that water requirements would be better expressed in relation to calorie/energy requirements with the dependence of the latter on age, size, gender, and physical activity level. Current understanding of the exquisitely complex and sensitive system that protects land animals against dehydration is covered and commentary is provided on the complications of acute and chronic dehydration in man, against which a better expression of water requirements might complement the physiological control of thirst. Indeed, the fine intrinsic regulation of hydration and water intake in individuals mitigates prevalent underhydration in populations and its effects on function and disease.

Regulation of fluid intake

To prevent dehydration, reptiles, birds, vertebrates, and all land animals have evolved an exquisitely sensitive network of physiological controls to maintain body water and fluid intake by thirst. Humans may drink for various reasons, particularly for hedonic ones, but drinking is most often due to water deficiency that triggers the so-called regulatory or physiological thirst. The mechanism of thirst is quite well understood today and the reason nonregulatory drinking is often encountered is related to the large capacity of the kidneys to rapidly eliminate excesses of water or to reduce urine secretion to temporarily economize on water. 1 But this excretory process can only postpone the necessity of drinking or of ceasing to drink an excess of water. Nonregulatory drinking is often confusing, particularly in wealthy societies that have highly palatable drinks or fluids that contain other substances the drinker seeks. The most common of these are sweeteners or alcohol for which water is used as a vehicle. Drinking these beverages is not due to excessive thirst or hyperdipsia, as can be shown by offering pure water to individuals instead and finding out that the same drinker is in fact hypodipsic (characterized by abnormally diminished thirst). 1

Fluid balance of the two compartments

Maintaining a constant water and mineral balance requires the coordination of sensitive detectors at different sites in the body linked by neural pathways with integrative centers in the brain that process this information. These centers are also sensitive to humoral factors (neurohormones) produced for the adjustment of diuresis, natriuresis, and blood pressure (angiotensin mineralocorticoids, vasopressin, atrial natriuretic factor). Instructions from the integrative centers to the “executive organs” (kidney, sweat glands, and salivary glands) and to the part of the brain responsible for corrective actions such as drinking are conveyed by certain nerves in addition to the above-mentioned substances. 1

Most of the components of fluid balance are controlled by homeostatic mechanisms responding to the state of body water. These mechanisms are sensitive and precise, and are activated with deficits or excesses of water amounting to only a few hundred milliliters. A water deficit produces an increase in the ionic concentration of the extracellular compartment, which takes water from the intracellular compartment causing cells to shrink. This shrinkage is detected by two types of brain sensors, one controlling drinking and the other controlling the excretion of urine by sending a message to the kidneys, mainly via the antidiuretic hormone vasopressin to produce a smaller volume of more concentrated urine. 18 When the body contains an excess of water, the reverse processes occur: the lower ionic concentration of body fluids allows more water to reach the intracellular compartment. The cells imbibe, drinking is inhibited, and the kidneys excrete more water.

The kidneys thus play a key role in regulating fluid balance. As discussed later, the kidneys function more efficiently in the presence of an abundant water supply. If the kidneys economize on water and produce more concentrated urine, they expend a greater amount of energy and incur more wear on their tissues. This is especially likely to occur when the kidneys are under stress, e.g., when the diet contains excessive amounts of salt or toxic substances that need to be eliminated. Consequently, drinking a sufficient amount of water helps protect this vital organ.

Regulatory drinking

Most drinking occurs in response to signals of water deficit. Apart from urinary excretion, the other main fluid regulatory process is drinking, which is mediated through the sensation of thirst. There are two distinct mechanisms of physiological thirst: the intracellular and the extracellular mechanisms. When water alone is lost, ionic concentration increases. As a result, the intracellular space yields some of its water to the extracellular compartment. Once again, the resulting shrinkage of cells is detected by brain receptors that send hormonal messages to induce drinking. This association with receptors that govern extracellular volume is accompanied by an enhancement of appetite for salt. Thus, people who have been sweating copiously prefer drinks that are relatively rich in Na+ salts rather than pure water. When excessive sweating is experienced, it is also important to supplement drinks with additional salt.

The brain's decision to start or stop drinking and to choose the appropriate drink is made before the ingested fluid can reach the intra- and extracellular compartments. The taste buds in the mouth send messages to the brain about the nature, and especially the salt content, of the ingested fluid, and neuronal responses are triggered as if the incoming water had already reached the bloodstream. These are the so-called anticipatory reflexes: they cannot be entirely “cephalic reflexes” because they arise from the gut as well as the mouth. 1

The anterior hypothalamus and pre-optic area are equipped with osmoreceptors related to drinking. Neurons in these regions show enhanced firing when the inner milieu gets hyperosmotic. Their firing decreases when water is loaded in the carotid artery that irrigates the neurons. It is remarkable that the same decrease in firing in the same neurons takes place when the water load is applied on the tongue instead of being injected into the carotid artery. This anticipatory drop in firing is due to communication from neural pathways that depart from the mouth and converge onto neurons that simultaneously sense the blood's inner milieu.

Nonregulatory drinking

Although everyone experiences thirst from time to time, it plays little role in the day-to-day control of water intake in healthy people living in temperate climates. In these regions, people generally consume fluids not to quench thirst, but as components of everyday foods (e.g., soup, milk), as beverages used as mild stimulants (tea, coffee), and for pure pleasure. A common example is alcohol consumption, which can increase individual pleasure and stimulate social interaction. Drinks are also consumed for their energy content, as in soft drinks and milk, and are used in warm weather for cooling and in cold weather for warming. Such drinking seems to also be mediated through the taste buds, which communicate with the brain in a kind of “reward system”, the mechanisms of which are just beginning to be understood. This bias in the way human beings rehydrate themselves may be advantageous because it allows water losses to be replaced before thirst-producing dehydration takes place. Unfortunately, this bias also carries some disadvantages. Drinking fluids other than water can contribute to an intake of caloric nutrients in excess of requirements, or in alcohol consumption that, in some people, may insidiously bring about dependence. For example, total fluid intake increased from 79 fluid ounces in 1989 to 100 fluid ounces in 2002 among US adults, with the difference representing intake of caloric beverages. 19

Effects of aging on fluid intake regulation

The thirst and fluid ingestion responses of older persons to a number of stimuli have been compared to those of younger persons. 20 Following water deprivation, older individuals are less thirsty and drink less fluid compared to younger persons. 21 , 22 The decrease in fluid consumption is predominantly due to a decrease in thirst, as the relationship between thirst and fluid intake is the same in young and old persons. Older persons drink insufficient amounts of water following fluid deprivation to replenish their body water deficit. 23 When dehydrated older persons are offered a highly palatable selection of drinks, this also fails to result in increased fluid intake. 23 The effects of increased thirst in response to an osmotic load have yielded variable responses, with one group reporting reduced osmotic thirst in older individuals 24 and one failing to find a difference. In a third study, young individuals ingested almost twice as much fluid as old persons, even though the older subjects had a much higher serum osmolality. 25

Overall, these studies support small changes in the regulation of thirst and fluid intake with aging. Defects in both osmoreceptors and baroreceptors appear to exist as do changes in the central regulatory mechanisms mediated by opioid receptors. 26 Because the elderly have low water reserves, it may be prudent for them to learn to drink regularly when not thirsty and to moderately increase their salt intake when they sweat. Better education on these principles may help prevent sudden hypotension and stroke or abnormal fatigue, which can lead to a vicious circle and eventually hospitalization.

Thermoregulation

Hydration status is critical to the body's process of temperature control. Body water loss through sweat is an important cooling mechanism in hot climates and in periods of physical activity. Sweat production is dependent upon environmental temperature and humidity, activity levels, and type of clothing worn. Water losses via skin (both insensible perspiration and sweating) can range from 0.3 L/h in sedentary conditions to 2.0 L/h in high activity in the heat, and intake requirements range from 2.5 to just over 3 L/day in adults under normal conditions, and can reach 6 L/day with high extremes of heat and activity. 27 , 28 Evaporation of sweat from the body results in cooling of the skin. However, if sweat loss is not compensated for with fluid intake, especially during vigorous physical activity, a hypohydrated state can occur with concomitant increases in core body temperature. Hypohydration from sweating results in a loss of electrolytes, as well as a reduction in plasma volume, and this can lead to increased plasma osmolality. During this state of reduced plasma volume and increased plasma osmolality, sweat output becomes insufficient to offset increases in core temperature. When fluids are given to maintain euhydration, sweating remains an effective compensation for increased core temperatures. With repeated exposure to hot environments, the body adapts to heat stress and cardiac output and stroke volume return to normal, sodium loss is conserved, and the risk for heat-stress-related illness is reduced. 29 Increasing water intake during this process of heat acclimatization will not shorten the time needed to adapt to the heat, but mild dehydration during this time may be of concern and is associated with elevations in cortisol, increased sweating, and electrolyte imbalances. 29

Children and the elderly have differing responses to ambient temperature and different thermoregulatory concerns than healthy adults. Children in warm climates may be more susceptible to heat illness than adults due to their greater surface area to body mass ratio, lower rate of sweating, and slower rate of acclimatization to heat. 30 , 31 Children may respond to hypohydration during activity with a higher relative increase in core temperature than adults, 32 and with a lower propensity to sweat, thus losing some of the benefits of evaporative cooling. However, it has been argued that children can dissipate a greater proportion of body heat via dry heat loss, and the concomitant lack of sweating provides a beneficial means of conserving water under heat stress. 30 Elders, in response to cold stress, show impairments in thermoregulatory vasoconstriction, and body water is shunted from plasma into the interstitial and intracellular compartments. 33 , 34 With respect to heat stress, water lost through sweating decreases the water content of plasma, and the elderly are less able to compensate for increased blood viscosity. 33 Not only do they have a physiological hypodipsia, but this can be exaggerated by central nervous system disease 35 and by dementia. 36 In addition, illness and limitations in daily living activities can further limit fluid intake. When reduced fluid intake is coupled with advancing age, there is a decrease in total body water. Older individuals have impaired renal fluid conservation mechanisms and, as noted above, have impaired responses to heat and cold stress. 33 , 34 All of these factors contribute to an increased risk of hypohydration and dehydration in the elderly.

With regard to physiology, the role of water in health is generally characterized in terms of deviations from an ideal hydrated state, generally in comparison to dehydration. The concept of dehydration encompasses both the process of losing body water and the state of dehydration. Much of the research on water and physical or mental functioning compares a euhydrated state, usually achieved by provision of water sufficient to overcome water loss, to a dehydrated state, which is achieved via withholding of fluids over time and during periods of heat stress or high activity. In general, provision of water is beneficial in individuals with a water deficit, but little research supports the notion that additional water in adequately hydrated individuals confers any benefit.

Physical performance

The role of water and hydration in physical activity, particularly in athletes and in the military, has been of considerable interest and is well-described in the scientific literature. 37 , – 39 During challenging athletic events, it is not uncommon for athletes to lose 6–10% of body weight through sweat, thus leading to dehydration if fluids have not been replenished. However, decrements in the physical performance of athletes have been observed under much lower levels of dehydration, i.e., as little as 2%. 38 Under relatively mild levels of dehydration, individuals engaging in rigorous physical activity will experience decrements in performance related to reduced endurance, increased fatigue, altered thermoregulatory capability, reduced motivation, and increased perceived effort. 40 , 41 Rehydration can reverse these deficits and reduce the oxidative stress induced by exercise and dehydration. 42 Hypohydration appears to have a more significant impact on high-intensity and endurance activity, such as tennis 43 and long-distance running, 44 than on anaerobic activities, 45 such as weight lifting, or on shorter-duration activities, such as rowing. 46

During exercise, individuals may not hydrate adequately when allowed to drink according to thirst. 32 After periods of physical exertion, voluntary fluid intake may be inadequate to offset fluid deficits. 1 Thus, mild-to-moderate dehydration can persist for some hours after the conclusion of physical activity. Research performed on athletes suggests that, principally at the beginning of the training season, they are at particular risk for dehydration due to lack of acclimatization to weather conditions or suddenly increased activity levels. 47 , 48 A number of studies show that performance in temperate and hot climates is affected to a greater degree than performance in cold temperatures. 41 , – 50 Exercise in hot conditions with inadequate fluid replacement is associated with hyperthermia, reduced stroke volume and cardiac output, decreases in blood pressure, and reduced blood flow to muscle. 51

During exercise, children may be at greater risk for voluntary dehydration. Children may not recognize the need to replace lost fluids, and both children as well as coaches need specific guidelines for fluid intake. 52 Additionally, children may require more time to acclimate to increases in environmental temperature than adults. 30 , 31 Recommendations are for child athletes or children in hot climates to begin athletic activities in a well-hydrated state and to drink fluids over and above the thirst threshold.

Cognitive performance

Water, or its lack (dehydration), can influence cognition. Mild levels of dehydration can produce disruptions in mood and cognitive functioning. This may be of special concern in the very young, very old, those in hot climates, and those engaging in vigorous exercise. Mild dehydration produces alterations in a number of important aspects of cognitive function such as concentration, alertness, and short-term memory in children (10–12 y), 32 young adults (18–25 y), 53 , – 56 and the oldest adults (50–82 y). 57 As with physical functioning, mild-to-moderate levels of dehydration can impair performance on tasks such as short-term memory, perceptual discrimination, arithmetic ability, visuomotor tracking, and psychomotor skills. 53 , – 56 However, mild dehydration does not appear to alter cognitive functioning in a consistent manner. 53 , – 58 In some cases, cognitive performance was not significantly affected in ranges from 2% to 2.6% dehydration. 56 , 58 Comparing across studies, performance on similar cognitive tests was divergent under dehydration conditions. 54 , 56 In studies conducted by Cian et al., 53 , 54 participants were dehydrated to approximately 2.8% either through heat exposure or treadmill exercise. In both studies, performance was impaired on tasks examining visual perception, short-term memory, and psychomotor ability. In a series of studies using exercise in conjunction with water restriction as a means of producing dehydration, D'Anci et al. 56 observed only mild decrements in cognitive performance in healthy young men and women athletes. In these experiments, the only consistent effect of mild dehydration was significant elevations of subjective mood score, including fatigue, confusion, anger, and vigor. Finally, in a study using water deprivation alone over a 24-h period, no significant decreases in cognitive performance were seen with 2.6% dehydration. 58 It is therefore possible that heat stress may play a critical role in the effects of dehydration on cognitive performance.

Reintroduction of fluids under conditions of mild dehydration can reasonably be expected to reverse dehydration-induced cognitive deficits. Few studies have examined how fluid reintroduction may alleviate the negative effects of dehydration on cognitive performance and mood. One study 59 examined how water ingestion affected arousal and cognitive performance in young people following a period of 12-h water restriction. While cognitive performance was not affected by either water restriction or water consumption, water ingestion affected self-reported arousal. Participants reported increased alertness as a function of water intake. Rogers et al. 60 observed a similar increase in alertness following water ingestion in both high- and low-thirst participants. Water ingestion, however, had opposite effects on cognitive performance as a function of thirst. High-thirst participants' performance on a cognitively demanding task improved following water ingestion, but low-thirst participants' performance declined. In summary, hydration status consistently affected self-reported alertness, but effects on cognition were less consistent.

Several recent studies have examined the utility of providing water to school children on attentiveness and cognitive functioning in children. 61 , – 63 In these experiments, children were not fluid restricted prior to cognitive testing, but were allowed to drink as usual. Children were then provided with a drink or no drink 20–45 min before the cognitive test sessions. In the absence of fluid restriction and without physiological measures of hydration status, the children in these studies should not be classified as dehydrated. Subjective measures of thirst were reduced in children given water, 62 and voluntary water intake in children varied from 57 mL to 250 mL. In these studies, as in the studies in adults, the findings were divergent and relatively modest. In the research led by Edmonds et al., 61 , 62 children in the groups given water showed improvements in visual attention. However, effects on visual memory were less consistent, with one study showing no effects of drinking water on a spot-the-difference task in 6–7-year-old children 61 and the other showing a significant improvement in a similar task in 7–9-year-old children. 62 In the research described by Benton and Burgess, 63 memory performance was improved by provision of water but sustained attention was not altered with provision of water in the same children.

Taken together, these studies indicate that low-to-moderate dehydration may alter cognitive performance. Rather than indicating that the effects of hydration or water ingestion on cognition are contradictory, many of the studies differ significantly in methodology and in measurement of cognitive behaviors. These variances in methodology underscore the importance of consistency when examining relatively subtle chances in overall cognitive performance. However, in those studies in which dehydration was induced, most combined heat and exercise; this makes it difficult to disentangle the effects of dehydration on cognitive performance in temperate conditions from the effects of heat and exercise. Additionally, relatively little is known about the mechanism of mild dehydration's effects on mental performance. It has been proposed that mild dehydration acts as a physiological stressor that competes with and draws attention from cognitive processes. 64 However, research on this hypothesis is limited and merits further exploration.

Dehydration and delirium

Dehydration is a risk factor for delirium and for delirium presenting as dementia in the elderly and in the very ill. 65 , – 67 Recent work shows that dehydration is one of several predisposing factors for confusion observed in long-term-care residents 67 ; however, in this study, daily water intake was used as a proxy measure for dehydration rather than other, more direct clinical assessments such as urine or plasma osmolality. Older people have been reported as having reduced thirst and hypodipsia relative to younger people. In addition, fluid intake and maintenance of water balance can be complicated by factors such as disease, dementia, incontinence, renal insufficiency, restricted mobility, and drug side effects. In response to primary dehydration, older people have less thirst sensation and reduced fluid intakes in comparison to younger people. However, in response to heat stress, while older people still display a reduced thirst threshold, they do ingest comparable amounts of fluid to younger people. 20

Gastrointestinal function

Fluids in the diet are generally absorbed in the proximal small intestine, and the absorption rate is determined by the rate of gastric emptying to the small intestine. Therefore, the total volume of fluid consumed will eventually be reflected in water balance, but the rate at which rehydration occurs is dependent upon factors affecting the rate of delivery of fluids to the intestinal mucosa. The gastric emptying rate is generally accelerated by the total volume consumed and slowed by higher energy density and osmolality. 68 In addition to water consumed in food (1 L/day) and beverages (circa 2–3 L/day), digestive secretions account for a far greater portion of water that passes through and is absorbed by the gastrointestinal tract (circa 8 L/day). 69 The majority of this water is absorbed by the small intestine, with a capacity of up to 15 L/day with the colon absorbing some 5 L/day. 69

Constipation, characterized by slow gastrointestinal transit, small, hard stools, and difficulty in passing stool, has a number of causes, including medication use, inadequate fiber intake, poor diet, and illness. 70 Inadequate fluid consumption is touted as a common culprit in constipation, and increasing fluid intake is a frequently recommended treatment. Evidence suggests, however, that increasing fluids is only useful to individuals in a hypohydrated state, and is of little utility in euhydrated individuals. 70 In young children with chronic constipation, increasing daily water intake by 50% did not affect constipation scores. 71 For Japanese women with low fiber intake, concomitant low water intake in the diet is associated with increased prevalence of constipation. 72 In older individuals, low fluid intake is a predictor for increased levels of acute constipation, 73 , 74 with those consuming the least amount of fluid having over twice the frequency of constipation episodes than those consuming the most fluid. In one trial, researchers compared the utility of carbonated mineral water in reducing functional dyspepsia and constipation scores to tap water in individuals with functional dyspepsia. 75 When comparing carbonated mineral water to tap water, participants reported improvements in subjective gastric symptoms, but there were no significant improvements in gastric or intestinal function. The authors indicate it is not possible to determine to what degree the mineral content of the two waters contributed to perceived symptom relief, as the mineral water contained greater levels of magnesium and calcium than the tap water. The available evidence suggests that increased fluid intake should only be indicated in individuals in a hypohydrated state. 69 , 71

Significant water loss can occur through the gastrointestinal tract, and this can be of great concern in the very young. In developing countries, diarrheal diseases are a leading cause of death in children, resulting in approximately 1.5–2.5 million deaths per year. 76 Diarrheal illness results not only in a reduction in body water, but also in potentially lethal electrolyte imbalances. Mortality in such cases can many times be prevented with appropriate oral rehydration therapy, by which simple dilute solutions of salt and sugar in water can replace fluid lost by diarrhea. Many consider application of oral rehydration therapy to be one of the significant public health developments of the last century. 77

Kidney function

As noted above, the kidney is crucial in regulating water balance and blood pressure as well as removing waste from the body. Water metabolism by the kidney can be classified into regulated and obligate. Water regulation is hormonally mediated, with the goal of maintaining a tight range of plasma osmolality (between 275 and 290 mOsm/kg). Increases in plasma osmolality and activation of osmoreceptors (intracellular) and baroreceptors (extracellular) stimulate hypothalamic release of arginine vasopressin (AVP). AVP acts at the kidney to decrease urine volume and promote retention of water, and the urine becomes hypertonic. With decreased plasma osmolality, vasopressin release is inhibited, and the kidney increases hypotonic urinary output.

In addition to regulating fluid balance, the kidneys require water for the filtration of waste from the bloodstream and excretion via urine. Water excretion via the kidney removes solutes from the blood, and a minimum obligate urine volume is required to remove the solute load with a maximum output volume of 1 L/h. 78 This obligate volume is not fixed, but is dependent upon the amount of metabolic solutes to be excreted and levels of AVP. Depending on the need for water conservation, basal urine osmolality ranges from 40 mOsm/kg to a maximum of 1,400 mOsm/kg. 78 The ability to both concentrate and dilute urine decreases with age, with a lower value of 92 mOsm/kg and an upper range falling between 500 and 700 mOsm/kg for individuals over the age of 70 years. 79 , – 81 Under typical conditions, in an average adult, urine volume of 1.5 to 2.0 L/day would be sufficient to clear a solute load of 900 to 1,200 mOsm/day. During water conservation and the presence of AVP, this obligate volume can decrease to 0.75–1.0 L/day and during maximal diuresis up to 20 L/day can be required to remove the same solute load. 78 , – 81 In cases of water loading, if the volume of water ingested cannot be compensated for with urine output, having overloaded the kidney's maximal output rate, an individual can enter a hyponatremic state.

Heart function and hemodynamic response

Blood volume, blood pressure, and heart rate are closely linked. Blood volume is normally tightly regulated by matching water intake and water output, as described in the section on kidney function. In healthy individuals, slight changes in heart rate and vasoconstriction act to balance the effect of normal fluctuations in blood volume on blood pressure. 82 Decreases in blood volume can occur, through blood loss (or blood donation), or loss of body water through sweat, as seen with exercise. Blood volume is distributed differently relative to the position of the heart, whether supine or upright, and moving from one position to the other can lead to increased heart rate, a fall in blood pressure, and, in some cases, syncope. This postural hypotension (or orthostatic hypotension) can be mediated by drinking 300–500 mL of water. 83 , 84 Water intake acutely reduces heart rate and increases blood pressure in both normotensive and hypertensive individuals. 85 These effects of water intake on the pressor effect and heart rate occur within 15–20 min of drinking water and can last for up to 60 min. Water ingestion is also beneficial in preventing vasovagal reaction with syncope in blood donors at high risk for post-donation syncope. 86 The effect of water intake in these situations is thought to be due to effects on the sympathetic nervous system rather than to changes in blood volume. 83 , 84 Interestingly, in rare cases, individuals may experience bradycardia and syncope after swallowing cold liquids. 87 , – 89 While swallow syncope can be seen with substances other than water, swallow syncope further supports the notion that the result of water ingestion in the pressor effect has both a neural component as well as a cardiac component.

Water deprivation and dehydration can lead to the development of headache. 90 Although this observation is largely unexplored in the medical literature, some observational studies indicate that water deprivation, in addition to impairing concentration and increasing irritability, can serve as a trigger for migraine and can also prolong migraine. 91 , 92 In those with water deprivation-induced headache, ingestion of water provided relief from headache in most individuals within 30 min to 3 h. 92 It is proposed that water deprivation-induced headache is the result of intracranial dehydration and total plasma volume. Although provision of water may be useful in relieving dehydration-related headache, the utility of increasing water intake for the prevention of headache is less well documented.

The folk wisdom that drinking water can stave off headaches has been relatively unchallenged, and has more traction in the popular press than in the medical literature. Recently, one study examined increased water intake and headache symptoms in headache patients. 93 In this randomized trial, patients with a history of different types of headache, including migraine and tension headache, were either assigned to a placebo condition (a nondrug tablet) or the increased water condition. In the water condition, participants were instructed to consume an additional volume of 1.5 L water/day on top of what they already consumed in foods and fluids. Water intake did not affect the number of headache episodes, but it was modestly associated with reduction in headache intensity and reduced duration of headache. The data from this study suggest that the utility of water as prophylaxis is limited in headache sufferers, and the ability of water to reduce or prevent headache in the broader population remains unknown.

One of the more pervasive myths regarding water intake is its relation to improvements of the skin or complexion. By improvement, it is generally understood that individuals are seeking to have a more “moisturized” look to the surface skin, or to minimize acne or other skin conditions. Numerous lay sources such as beauty and health magazines as well as postings on the Internet suggest that drinking 8–10 glasses of water a day will “flush toxins from the skin” and “give a glowing complexion” despite a general lack of evidence 94 , 95 to support these proposals. The skin, however, is important for maintaining body water levels and preventing water loss into the environment.

The skin contains approximately 30% water, which contributes to plumpness, elasticity, and resiliency. The overlapping cellular structure of the stratum corneum and lipid content of the skin serves as “waterproofing” for the body. 96 Loss of water through sweat is not indiscriminate across the total surface of the skin, but is carried out by eccrine sweat glands, which are evenly distributed over most of the body surface. 97 Skin dryness is usually associated with exposure to dry air, prolonged contact with hot water and scrubbing with soap (both strip oils from the skin), medical conditions, and medications. While more serious levels of dehydration can be reflected in reduced skin turgor, 98 , 99 with tenting of the skin acting as a flag for dehydration, overt skin turgor in individuals with adequate hydration is not altered. Water intake, particularly in individuals with low initial water intake, can improve skin thickness and density as measured by sonogram, 100 offsets transepidermal water loss, and can improve skin hydration. 101 Adequate skin hydration, however, is not sufficient to prevent wrinkles or other signs of aging, which are related to genetics and to sun and environmental damage. Of more utility to individuals already consuming adequate fluids is the use of topical emollients; these will improve skin barrier function and improve the look and feel of dry skin. 102 , 103

Many chronic diseases have multifactorial origins. In particular, differences in lifestyle and the impact of environment are known to be involved and constitute risk factors that are still being evaluated. Water is quantitatively the most important nutrient. In the past, scientific interest with regard to water metabolism was mainly directed toward the extremes of severe dehydration and water intoxication. There is evidence, however, that mild dehydration may also account for some morbidities. 4 , 104 There is currently no consensus on a “gold standard” for hydration markers, particularly for mild dehydration. As a consequence, the effects of mild dehydration on the development of several disorders and diseases have not been well documented.

There is strong evidence showing that good hydration reduces the risk of urolithiasis (see Table 2 for evidence categories). Less strong evidence links good hydration with reduced incidence of constipation, exercise asthma, hypertonic dehydration in the infant, and hyperglycemia in diabetic ketoacidosis. Good hydration is associated with a reduction in urinary tract infections, hypertension, fatal coronary heart disease, venous thromboembolism, and cerebral infarct, but all these effects need to be confirmed by clinical trials. For other conditions such as bladder or colon cancer, evidence of a preventive effect of maintaining good hydration is not consistent (see Table 3 ).

Categories of evidence used in evaluating the quality of reports.

Data adapted from Manz. 104

Summary of evidence for association of hydration status with chronic diseases.

Categories of evidence: described in Table 2 .

Water consumption, water requirements, and energy intake are linked in fairly complex ways. This is partially because physical activity and energy expenditures affect the need for water but also because a large shift in beverage consumption over the past century or more has led to consumption of a significant proportion of our energy intake from caloric beverages. Nonregulatory beverage intake, as noted earlier, has assumed a much greater role for individuals. 19 This section reviews current patterns of water intake and then refers to a full meta-analysis of the effects of added water on energy intake. This includes adding water to the diet and water replacement for a range of caloric and diet beverages, including sugar-sweetened beverages, juice, milk, and diet beverages. The third component is a discussion of water requirements and suggestions for considering the use of mL water/kcal energy intake as a metric.

Patterns and trends of water consumption

Measurement of total fluid water consumption in free-living individuals is fairly new in focus. As a result, the state of the science is poorly developed, data are most likely fairly incomplete, and adequate validation of the measurement techniques used is not available. Presented here are varying patterns and trends of water intake for the United States over the past three decades followed by a brief review of the work on water intake in Europe.

There is really no existing information to support an assumption that consumption of water alone or beverages containing water affects hydration differentially. 3 , 105 Some epidemiological data suggest water might have different metabolic effects when consumed alone rather than as a component of caffeinated or flavored or sweetened beverages; however, these data are at best suggestive of an issue deserving further exploration. 106 , 107 As shown below, the research of Ershow et al. indicates that beverages not consisting solely of water do contain less than 100% water.

One study in the United States has attempted to examine all the dietary sources of water. 16 , 17 These data are cited in Table 4 as the Ershow study and were based on National Food Consumption Survey food and fluid intake data from 1977–1978. These data are presented in Table 4 for children aged 2–18 years (Panel A) and for adults aged 19 years and older (Panel B). Ershow et al. 16 , 17 spent a great deal of time working out ways to convert USDA dietary data into water intake, including water absorbed during the cooking process, water in food, and all sources of drinking water.

Beverage pattern trends in the United States for children aged 2–18 years and adults aged 19 years and older, (nationally representative).

Note: The data are age and sex adjusted to 1965.

Values stem from the Ershow calculations. 16

These researchers created a number of categories and used a range of factors measured in other studies to estimate the water categories. The water that is found in food, based on food composition table data, was 393 mL for children. The water that was added as a result of cooking (e.g., rice) was 95 mL. Water consumed as a beverage directly as water was 624 mL. The water found in other fluids, as noted, comprised the remainder of the milliliters, with the highest levels in whole-fat milk and juices (506 mL). There is a small discrepancy between the Ershow data regarding total fluid intake measures for these children and the normal USDA figures. That is because the USDA does not remove milk fats and solids, fiber, and other food constituents found in beverages, particularly juice and milk.

A key point illustrated by these nationally representative US data is the enormous variability between survey waves in the amount of water consumed (see Figure 1 , which highlights the large variation in water intake as measured in these surveys). Although water intake by adults and children increased and decreased at the same time, for reasons that cannot be explained, the variation was greater among children than adults. This is partly because the questions the surveys posed varied over time and there was no detailed probing for water intake, because the focus was on obtaining measures of macro- and micronutrients. Dietary survey methods used in the past have focused on obtaining data on foods and beverages containing nutrient and non-nutritive sweeteners but not on water. Related to this are the huge differences between the the USDA surveys and the National Health and Nutrition Examination Survey (NHANES) performed in 1988–1994 and in 1999 and later. In addition, even the NHANES 1999–2002 and 2003–2006 surveys differ greatly. These differences reflect a shift in the mode of questioning with questions on water intake being included as part of a standard 24-h recall rather than as stand-alone questions. Water intake was not even measured in 1965, and a review of the questionnaires and the data reveals clear differences in the way the questions have been asked and the limitations on probes regarding water intake. Essentially, in the past people were asked how much water they consumed in a day and now they are asked for this information as part of a 24-h recall survey. However, unlike for other caloric and diet beverages, there are limited probes for water alone. The results must thus be viewed as crude approximations of total water intake without any strong research to show if they are over- or underestimated. From several studies of water and two ongoing randomized controlled trials performed by us, it is clear that probes that include consideration of all beverages and include water as a separate item result in the provision of more complete data.

Water consumption trends from USDA and NHANES surveys (mL/day/capita), nationally representative. Note: this includes water from fluids only, excluding water in foods. Sources for 1965, 1977–1978, 1989–1991, and 1994–1998, are USDA. Others are NHANES and 2005–2006 is joint USDA and NHANES.

Water consumption data for Europe are collected far more selectively than even the crude water intake questions from NHANES. A recent report from the European Food Safety Agency provides measures of water consumption from a range of studies in Europe. 4 , – 109 Essentially, what these studies show is that total water intake is lower across Europe than in the United States. As with the US data, none are based on long-term, carefully measured or even repeated 24-h recall measures of water intake from food and beverages. In an unpublished examination of water intake in UK adults in 1986–1987 and in 2001–2002, Popkin and Jebb have found that although intake increased by 226 mL/day over this time period, it was still only 1,787 mL/day in the latter period (unpublished data available from BP); this level is far below the 2,793 mL/day recorded in the United States for 2005–2006 or the earlier US figures for comparably aged adults.

A few studies have been performed in the United States and Europe utilizing 24-h urine and serum osmolality measures to determine total water turnover and hydration status. Results of these studies suggest that US adults consume over 2,100 mL of water per day while adults in Europe consume less than half a liter. 4 , 110 Data on total urine collection would appear to be another useful measure for examining total water intake. Of course, few studies aside from the Donald Study of an adolescent cohort in Germany have collected such data on population levels for large samples. 109

Effects of water consumption on overall energy intake

There is an extensive body of literature that focuses on the impact of sugar-sweetened beverages on weight and the risk of obesity, diabetes, and heart disease; however, the perspective of providing more water and its impact on health has not been examined. The literature on water does not address portion sizes; instead, it focuses mainly on water ad libitum or in selected portions compared with other caloric beverages. A detailed meta-analysis of the effects of water intake alone (i.e., adding additional water) and as a replacement for sugar-sweetened beverages, juice, milk, and diet beverages appears elsewhere. 111

In general, the results of this review suggest that water, when consumed in place of sugar-sweetened beverages, juice, and milk, is linked with reduced energy intake. This finding is mainly derived from clinical feeding studies but also from one very good randomized, controlled school intervention and several other epidemiological and intervention studies. Aside from the issue of portion size, factors such as the timing of beverage and meal intake (i.e., the delay between consumption of the beverage and consumption of the meal) and types of caloric sweeteners remain to be considered. However, when beverages are consumed in normal free-living conditions in which five to eight daily eating occasions are the norm, the delay between beverage and meal consumption may matter less. 112 , – 114

The literature on the water intake of children is extremely limited. However, the excellent German school intervention with water suggests the effects of water on the overall energy intake of children might be comparable to that of adults. 115 In this German study, children were educated on the value of water and provided with special filtered drinking fountains and water bottles in school. The intervention schoolchildren increased their water intake by 1.1 glasses/day ( P  < 0.001) and reduced their risk of overweight by 31% (OR = 0.69, P  = 0.40).

Classically, water data are examined in terms of milliliters (or some other measure of water volume consumed per capita per day by age group). This measure does not link fluid intake and caloric intake. Disassociation of fluid and calorie intake is difficult for clinicians dealing with older persons with reduced caloric intake. This milliliter water measure assumes some mean body size (or surface area) and a mean level of physical activity – both of which are determinants of not only energy expenditure but also water balance. Children are dependent on adults for access to water, and studies suggest that their larger surface area to volume ratio makes them susceptible to changes in skin temperatures linked with ambient temperature shifts. 116 One option utilized by some scholars is to explore food and beverage intake in milliliters per kilocalorie (mL/kcal), as was done in the 1989 US recommended dietary allowances. 4 , 117 This is an option that is interpretable for clinicians and which incorporates, in some sense, body size or surface area and activity. Its disadvantage is that water consumed with caloric beverages affects both the numerator and the denominator; however, an alternative measure that could be independent of this direct effect on body weight and/or total caloric intake is not presently known.

Despite its critical importance in health and nutrition, the array of available research that serves as a basis for determining requirements for water or fluid intake, or even rational recommendations for populations, is limited in comparison with most other nutrients. While this deficit may be partly explained by the highly sensitive set of neurophysiological adaptations and adjustments that occur over a large range of fluid intakes to protect body hydration and osmolarity, this deficit remains a challenge for the nutrition and public health community. The latest official effort at recommending water intake for different subpopulations occurred as part of the efforts to establish Dietary Reference Intakes in 2005, as reported by the Institute of Medicine of the National Academies of Science. 3 As a graphic acknowledgment of the limited database upon which to express estimated average requirements for water for different population groups, the Committee and the Institute of Medicine stated: “While it might appear useful to estimate an average requirement (an EAR) for water, an EAR based on data is not possible.” Given the extreme variability in water needs that are not solely based on differences in metabolism, but also on environmental conditions and activities, there is not a single level of water intake that would assure adequate hydration and optimum health for half of all apparently healthy persons in all environmental conditions. Thus, an adequate intake (AI) level was established in place of an EAR for water.

The AIs for different population groups were set as the median water intakes for populations, as reported in the National Health and Nutrition Examination Surveys; however, the intake levels reported in these surveys varied greatly based on the survey years (e.g., NHANES 1988–1994 versus NHANES 1999–2002) and were also much higher than those found in the USDA surveys (e.g., 1989–1991, 1994–1998, or 2005–2006). If the AI for adults, as expressed in Table 5 , is taken as a recommended intake, the wisdom of converting an AI into a recommended water or fluid intake seems questionable. The first problem is the almost certain inaccuracy of the fluid intake information from the national surveys, even though that problem may also exist for other nutrients. More importantly, from the standpoint of translating an AI into a recommended fluid intake for individuals or populations, is the decision that was made when setting the AI to add an additional roughly 20% of water intake, which is derived from some foods in addition to water and beverages. While this may have been a legitimate effort to use total water intake as a basis for setting the AI, the recommendations that derive from the IOM report would be better directed at recommendations for water and other fluid intake on the assumption that the water content of foods would be a “passive” addition to total water intake. In this case, the observations of the dietary reference intake committee that it is necessary for water intake to meet needs imposed by metabolism and environmental conditions must be extended to consider three added factors, namely body size, gender, and physical activity. Those are the well-studied factors that allow a rather precise measurement and determination of energy intake requirements. It is, therefore, logical that those same factors might underlie recommendations to meet water intake needs in the same populations and individuals. Consideration should also be given to the possibility that water intake needs would best be expressed relative to the calorie requirements, as is done regularly in the clinical setting, and data should be gathered to this end through experimental and population research.

Water requirements expressed in relation to energy recommendations.

AI for total fluids derived from dietary reference intakes for water, potassium, sodium, chloride, and sulphate.

Ratios for water intake based on the AI for water in liters/day calculated using EER for each range of physical activity. EER adapted from the Institute of Medicine Dietary Reference Intakes Macronutrients Report, 2002.

It is important to note that only a few countries include water on their list of nutrients. 118 The European Food Safety Authority is developing a standard for all of Europe. 105 At present, only the United States and Germany provide AI values for water. 3 , 119

Another approach to the estimation of water requirements, beyond the limited usefulness of the AI or estimated mean intake, is to express water intake requirements in relation to energy requirements in mL/kcal. An argument for this approach includes the observation that energy requirements for each age and gender group are strongly evidence-based and supported by extensive research taking into account both body size and activity level, which are crucial determinants of energy expenditure that must be met by dietary energy intake. Such measures of expenditure have used highly accurate methods, such as doubly labeled water; thus, estimated energy requirements have been set based on solid data rather than the compromise inherent in the AIs for water. Those same determinants of energy expenditure and recommended intake are also applicable to water utilization and balance, and this provides an argument for pegging water/fluid intake recommendations to the better-studied energy recommendations. The extent to which water intake and requirements are determined by energy intake and expenditure is understudied, but in the clinical setting it has long been practice to supply 1 mL/kcal administered by tube to patients who are unable to take in food or fluids. Factors such as fever or other drivers of increased metabolism affect both energy expenditure and fluid loss and are thus linked in clinical practice. This concept may well deserve consideration in the setting of population intake goals.

Finally, for decades there has been discussion about expressing nutrient requirements per 1,000 kcal so that a single number would apply reasonably across the spectrum of age groups. This idea, which has never been adopted by the Institute of Medicine and the National Academies of Science, may lend itself to an improved expression of water/fluid intake requirements, which must eventually replace the AIs. Table 5 presents the IOM water requirements and then develops a ratio of mL/kcal based on them. The European Food Safety Agency refers positively to the possibility of expressing water intake recommendations in mL/kcal as a function of energy requirements. 105 Outliers in the adult male categories, which reach ratios as high as 1.5, may well be based on the AI data from the United States, which are above those in the more moderate and likely more accurate European recommendations.

The topic of utilizing mL/kcal to examine water intake and water gaps is explored in Table 6 , which takes the full set of water intake AIs for each age-gender grouping and examines total intake. The data suggest a high level of fluid deficiency. Since a large proportion of fluids in the United States is based on caloric beverages and this proportion has changed markedly over the past 30 years, fluid intake increases both the numerator and the denominator of this mL/kcal relationship. Nevertheless, even using 1 mL/kcal as the AI would leave a gap for all children and adolescents. The NHANES physical activity data were also translated into METS/day to categorize all individuals by physical activity level and thus varying caloric requirements. Use of these measures reveals a fairly large fluid gap, particularly for adult males as well as children ( Table 6 ).

Water intake and water intake gaps based on US Water Adequate Intake Recommendations (based on utilization of water and physical activity data from NHANES 2005–2006).

Note: Recommended water intake for actual activity level is the upper end of the range for moderate and active.

A weighted average for the proportion of individuals in each METS-based activity level.

This review has pointed out a number of issues related to water, hydration, and health. Since water is undoubtedly the most important nutrient and the only one for which an absence will prove lethal within days, understanding of water measurement and water requirements is very important. The effects of water on daily performance and short- and long-term health are quite clear. The existing literature indicates there are few negative effects of water intake while the evidence for positive effects is quite clear.

Little work has been done to measure total fluid intake systematically, and there is no understanding of measurement error and best methods of understanding fluid intake. The most definitive US and European documents on total water requirements are based on these extant intake data. 3 , 105 The absence of validation methods for water consumption intake levels and patterns represents a major gap in knowledge. Even varying the methods of probing in order to collect better water recall data has been little explored.

On the other side of the issue is the need to understand total hydration status. There are presently no acceptable biomarkers of hydration status at the population level, and controversy exists about the current knowledge of hydration status among older Americans. 6 , 120 Thus, while scholars are certainly focused on attempting to create biomarkers for measuring hydration status at the population level, the topic is currently understudied.

As noted, the importance of understanding the role of fluid intake on health has emerged as a topic of increasing interest, partially because of the trend toward rising proportions of fluids being consumed in the form of caloric beverages. The clinical, epidemiological, and intervention literature on the effects of added water on health are covered in a related systematic review. 111 The use of water as a replacement for sugar-sweetened beverages, juice, or whole milk has clear effects in that energy intake is reduced by about 10–13% of total energy intake. However, only a few longer-term systematic interventions have investigated this topic and no randomized, controlled, longer-term trials have been published to date. There is thus very minimal evidence on the effects of just adding water to the diet and of replacing water with diet beverages.

There are many limitations to this review. One certainly is the lack of discussion of potential differences in the metabolic functioning of different types of beverages. 121 Since the literature in this area is sparse, however, there is little basis for delving into it at this point. A discussion of the potential effects of fructose (from all caloric sweeteners when consumed in caloric beverages) on abdominal fat and all of the metabolic conditions directly linked with it (e.g., diabetes) is likewise lacking. 122 , – 125 A further limitation is the lack of detailed review of the array of biomarkers being considered to measure hydration status. Since there is no measurement in the field today that covers more than a very short time period, except for 24-hour total urine collection, such a discussion seems premature.

Some ways to examine water requirements have been suggested in this review as a means to encourage more dialogue on this important topic. Given the significance of water to our health and of caloric beverages to our total energy intake, as well as the potential risks of nutrition-related noncommunicable diseases, understanding both the requirements for water in relation to energy requirements, and the differential effects of water versus other caloric beverages, remain important outstanding issues.

This review has attempted to provide some sense of the importance of water to our health, its role in relationship to the rapidly increasing rates of obesity and other related diseases, and the gaps in present understanding of hydration measurement and requirements. Water is essential to our survival. By highlighting its critical role, it is hoped that the focus on water in human health will sharpen.

The authors wish to thank Ms. Frances L. Dancy for administrative assistance, Mr. Tom Swasey for graphics support, Dr. Melissa Daniels for assistance, and Florence Constant (Nestle's Water Research) for advice and references.

This work was supported by the Nestlé Waters, Issy-les-Moulineaux, France, 5ROI AGI0436 from the National Institute on Aging Physical Frailty Program, and NIH R01-CA109831 and R01-CA121152.

Declaration of interest

The authors have no relevant interests to declare.

Nicolaidis S . Physiology of thirst . In: Arnaud MJ , ed. Hydration Throughout Life . Montrouge: John Libbey Eurotext ; 1998 : 247 .

Google Scholar

Jequier E Constant F . Water as an essential nutrient: the physiological basis of hydration . Eur J Clin Nutr. 2010 ; 64 : 115 – 123 .

Institute of Medicine . Panel on Dietary Reference Intakes for Electrolytes and Water. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate . Washington, DC: The National Academies Press ; 2005 .

Manz F Wentz A . Hydration status in the United States and Germany . Nutr Rev. 2005 ; 63 :(Suppl): S55 – S62 .

European Food Safety Authority . Scientific opinion of the Panel on Dietetic Products Nutrition and Allergies. Draft dietary reference values for water . EFSA J. 2008 : 2 – 49 .

Stookey JD . High prevalence of plasma hypertonicity among community-dwelling older adults: results from NHANES III . J Am Diet Assoc. 2005 ; 105 : 1231 – 1239 .

Armstrong LE . Hydration assessment techniques . Nutr Rev. 2005 ; 63 (Suppl): S40 – S54 .

Bar-David Y Urkin J Kozminsky E . The effect of voluntary dehydration on cognitive functions of elementary school children . Acta Paediatr. 2005 ; 94 : 1667 – 1673 .

Shirreffs S . Markers of hydration status . J Sports Med Phys Fitness. 2000 ; 40 : 80 – 84 .

Popowski L Oppliger R Lambert G Johnson R Johnson A Gisolfi C . Blood and urinary measures of hydration status during progressive acute dehydration . Med Sci Sports Exerc. 2001 ; 33 : 747 – 753 .

Bar-David Y Landau D Bar-David Z Pilpel D Philip M . Urine osmolality among elementary schoolchildren living in a hot climate: implications for dehydration . Ambulatory Child Health. 1998 ; 4 : 393 – 397 .

Fadda R Rapinett G Grathwohl D Parisi M Fanari R Schmitt J . The Benefits of Drinking Supplementary Water at School on Cognitive Performance in Children . Washington, DC: International Society for Developmental Psychobiology ; 2008 : Abstract from poster session at the 41st Annual Conference of International Society for Psychobiology. Abstracts published in: Developmental Psychobiology 2008: v. 50(7): 726 . http://www3.interscience.wiley.com/cgi-bin/fulltext/121421361/PDFSTART

Eckhardt CL Adair LS Caballero B , et al . Estimating body fat from anthropometry and isotopic dilution: a four-country comparison . Obes Res. 2003 ; 11 : 1553 – 1562 .

Moreno LA Sarria A Popkin BM . The nutrition transition in Spain: a European Mediterranean country . Eur J Clin Nutr. 2002 ; 56 : 992 – 1003 .

Lee MJ Popkin BM Kim S . The unique aspects of the nutrition transition in South Korea: the retention of healthful elements in their traditional diet . Public Health Nutr. 2002 ; 5 : 197 – 203 .

Ershow AG Brown LM Cantor KP . Intake of tapwater and total water by pregnant and lactating women . Am J Public Health. 1991 ; 81 : 328 – 334 .

Ershow AG Cantor KP . Total Water and Tapwater Intake in the United States: Population-Based Estimates of Quantities and Sources . Bethesda, MD: FASEB/LSRO ; 1989 .

Ramsay DJ . Homeostatic control of water balance . In: Arnaud MJ , ed. Hydration Throughout Life . Montrouge: John Libbey Eurotext ; 1998 : 9 – 18 .

Duffey K Popkin BM . Shifts in patterns and consumption of beverages between 1965 and 2002 . Obesity. 2007 ; 15 : 2739 – 2747 .

Morley JE Miller DK Zdodowski C Guitierrez B Perry IIIHM . Fluid intake, hydration and aging . In: Arnaud MJ , ed. Hydration Throughout Life: International Conference Vittel (France) . Montrouge: John Libbey Eurotext ; 1998 : 247 .

Phillips PA Rolls BJ Ledingham JG , et al . Reduced thirst after water deprivation in healthy elderly men . N Engl J Med. 1984 ; 311 : 753 – 759 .

Mack GW Weseman CA Langhans GW Scherzer H Gillen CM Nadel ER . Body fluid balance in dehydrated healthy older men: thirst and renal osmoregulation . J Appl Physiol. 1994 ; 76 : 1615 – 1623 .

Phillips PA Johnston CI Gray L . Disturbed fluid and electrolyte homoeostasis following dehydration in elderly people . Age Ageing. 1993 ; 22 : S26 – S33 .

Phillips PA Bretherton M Johnston CI Gray L . Reduced osmotic thirst in healthy elderly men . Am J Physiol. 1991 ; 261 : R166 – R171 .

Davies I O'Neill PA McLean KA Catania J Bennett D . Age-associated alterations in thirst and arginine vasopressin in response to a water or sodium load . Age Ageing. 1995 ; 24 : 151 – 159 .

Silver AJ Morley JE . Role of the opioid system in the hypodipsia associated with aging . J Am Geriatr Soc. 1992 ; 40 : 556 – 560 .

Sawka MN Latzka WA Matott RP Montain SJ . Hydration effects on temperature regulation . Int J Sports Med. 1998 ; 19 (Suppl 2 ): S108 – S110 .

Sawka MN Cheuvront SN Carter R 3rd . Human water needs . Nutr Rev. 2005 ; 63 (Suppl): S30 – S39 .

Armstrong LE. Heat acclimatization . In: TD Fahey, ed. Encyclopedia of Sports Medicine and Science . Internet Society for Sport Science: http://sportsci.org . 10 March 1998 .

Falk B Dotan R . Children's thermoregulation during exercise in the heat: a revisit . Appl Physiol Nutr Metab. 2008 ; 33 : 420 – 427 .

Bytomski JR Squire DL . Heat illness in children . Curr Sports Med Rep. 2003 ; 2 : 320 – 324 .

Bar-Or O Dotan R Inbar O Rotshtein A Zonder H . Voluntary hypohydration in 10- to 12-year-old boys . J Appl Physiol. 1980 ; 48 : 104 – 108 .

Vogelaere P Pereira C . Thermoregulation and aging . Rev Port Cardiol. 2005 ; 24 : 747 – 761 .

Thompson-Torgerson CS Holowatz LA Kenney WL . Altered mechanisms of thermoregulatory vasoconstriction in aged human skin . Exerc Sport Sci Rev. 2008 ; 36 : 122 – 127 .

Miller PD Krebs RA Neal BJ McIntyre DO . Hypodipsia in geriatric patients . Am J Med. 1982 ; 73 : 354 – 356 .

Albert SG Nakra BR Grossberg GT Caminal ER . Drinking behavior and vasopressin responses to hyperosmolality in Alzheimer's disease . Int Psychogeriatr. 1994 ; 6 : 79 – 86 .

Maughan RJ Shirreffs SM Watson P . Exercise, heat, hydration and the brain . J Am Coll Nutr. 2007 ; 26 (Suppl): S604 – S612 .

Murray B . Hydration and physical performance . J Am Coll Nutr. 2007 ; 26 (Suppl): S542 – S548 .

Sawka MN Noakes TD . Does dehydration impair exercise performance? Med Sci Sports Exerc. 2007 ; 39 : 1209 – 1217 .

Montain SJ Coyle EF . Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise . J Appl Physiol. 1992 ; 73 : 1340 – 1350 .

Cheuvront SN . Carter R, 3rd, Sawka MN. Fluid balance and endurance exercise performance . Curr Sports Med Rep. 2003 ; 2 : 202 – 208 .

Paik IY Jeong MH Jin HE , et al . Fluid replacement following dehydration reduces oxidative stress during recovery . Biochem Biophys Res Commun. 2009 ; 383 : 103 – 107 .

Kovacs MS . A review of fluid and hydration in competitive tennis . Int J Sports Physiol Perform. 2008 ; 3 : 413 – 423 .

Cheuvront SN Montain SJ Sawka MN . Fluid replacement and performance during the marathon . Sports Med. 2007 ; 37 : 353 – 357 .

Cheuvront SN . Carter R, 3rd, Haymes EM, Sawka MN. No effect of moderate hypohydration or hyperthermia on anaerobic exercise performance . Med Sci Sports Exerc. 2006 ; 38 : 1093 – 1097 .

Penkman MA Field CJ Sellar CM Harber VJ Bell GJ . Effect of hydration status on high-intensity rowing performance and immune function . Int J Sports Physiol Perform. 2008 ; 3 : 531 – 546 .

Bergeron MF McKeag DB Casa DJ , et al . Youth football: heat stress and injury risk . Med Sci Sports Exerc. 2005 ; 37 : 1421 – 1430 .

Godek SF Godek JJ Bartolozzi AR . Hydration status in college football players during consecutive days of twice-a-day preseason practices . Am J Sports Med. 2005 ; 33 : 843 – 851 .

Cheuvront SN Carter R 3rd Castellani JW Sawka MN . Hypohydration impairs endurance exercise performance in temperate but not cold air . J Appl Physiol. 2005 ; 99 : 1972 – 1976 .

Kenefick RW Mahood NV Hazzard MP Quinn TJ Castellani JW . Hypohydration effects on thermoregulation during moderate exercise in the cold . Eur J Appl Physiol. 2004 ; 92 : 565 – 570 .

Maughan RJ Watson P Shirreffs SM . Heat and cold: what does the environment do to the marathon runner? Sports Med. 2007 ; 37 : 396 – 399 .

American Academy of Pediatrics . Climatic heat stress and the exercising child and adolescent. American Academy of Pediatrics. Committee on Sports Medicine and Fitness . Pediatrics. 2000 ; 106 : 158 – 159 .

Cian C Barraud PA Melin B Raphel C . Effects of fluid ingestion on cognitive function after heat stress or exercise-induced dehydration . Int J Psychophysiol. 2001 ; 42 : 243 – 251 .

Cian C Koulmann PA Barraud PA Raphel C Jimenez C Melin B . Influence of variations of body hydration on cognitive performance . J Psychophysiol. 2000 ; 14 : 29 – 36 .

Gopinathan PM Pichan G Sharma VM . Role of dehydration in heat stress-induced variations in mental performance . Arch Environ Health. 1988 ; 43 : 15 – 17 .

D'Anci KE Vibhakar A Kanter JH Mahoney CR Taylor HA . Voluntary dehydration and cognitive performance in trained college athletes . Percept Mot Skills. 2009 ; 109 : 251 – 269 .

Suhr JA Hall J Patterson SM Niinisto RT . The relation of hydration status to cognitive performance in healthy older adults . Int J Psychophysiol. 2004 ; 53 : 121 – 125 .

Szinnai G Schachinger H Arnaud MJ Linder L Keller U . Effect of water deprivation on cognitive-motor performance in healthy men and women . Am J Physiol Regul Integr Comp Physiol. 2005 ; 289 : R275 – R280 .

Neave N Scholey AB Emmett JR Moss M Kennedy DO Wesnes KA . Water ingestion improves subjective alertness, but has no effect on cognitive performance in dehydrated healthy young volunteers . Appetite. 2001 ; 37 : 255 – 256 .

Rogers PJ Kainth A Smit HJ . A drink of water can improve or impair mental performance depending on small differences in thirst . Appetite. 2001 ; 36 : 57 – 58 .

Edmonds CJ Jeffes B . Does having a drink help you think? 6–7-year-old children show improvements in cognitive performance from baseline to test after having a drink of water . Appetite. 2009 ; 53 : 469 – 472 .

Edmonds CJ Burford D . Should children drink more water?: the effects of drinking water on cognition in children . Appetite. 2009 ; 52 : 776 – 779 .

Benton D Burgess N . The effect of the consumption of water on the memory and attention of children . Appetite. 2009 ; 53 : 143 – 146 .

Cohen S . After effects of stress on human performance during a heat acclimatization regimen . Aviat Space Environ. Med. 1983 ; 54 : 709 – 713 .

Culp KR Wakefield B Dyck MJ Cacchione PZ DeCrane S Decker S . Bioelectrical impedance analysis and other hydration parameters as risk factors for delirium in rural nursing home residents . J Gerontol A Biol Sci Med Sci. 2004 ; 59 : 813 – 817 .

Lawlor PG . Delirium and dehydration: some fluid for thought? Support Care Cancer. 2002 ; 10 : 445 – 454 .

Voyer P Richard S Doucet L Carmichael PH . Predisposing factors associated with delirium among demented long-term care residents . Clin Nurs Res. 2009 ; 18 : 153 – 171 .

Leiper JB . Intestinal water absorption – implications for the formulation of rehydration solutions . Int J Sports Med. 1998 ; 19 (Suppl 2 ): S129 – S132 .

Ritz P Berrut G . The importance of good hydration for day-to-day health . Nutr Rev. 2005 ; 63 : S6 – S13 .

Arnaud MJ . Mild dehydration: a risk factor of constipation? Eur J Clin Nutr. 2003 ; 57 (Suppl): S88 – S95 .

Young RJ Beerman LE Vanderhoof JA . Increasing oral fluids in chronic constipation in children . Gastroenterol Nurs. 1998 ; 21 : 156 – 161 .

Murakami K Sasaki S Okubo H , et al . Association between dietary fiber, water and magnesium intake and functional constipation among young Japanese women . Eur J Clin Nutr. 2007 ; 61 : 616 – 622 .

Lindeman RD Romero LJ Liang HC Baumgartner RN Koehler KM Garry PJ . Do elderly persons need to be encouraged to drink more fluids? J Gerontol A Biol Sci Med Sci. 2000 ; 55 : M361 – M365 .

Robson KM Kiely DK Lembo T . Development of constipation in nursing home residents . Dis Colon Rectum. 2000 ; 43 : 940 – 943 .

Cuomo R Grasso R Sarnelli G , et al . Effects of carbonated water on functional dyspepsia and constipation . Eur J Gastroenterol Hepatol. 2002 ; 14 : 991 – 999 .

Kosek M Bern C Guerrant RL . The global burden of diarrhoeal disease, as estimated from studies published between 1992 and 2000 . Bull World Health Organ. 2003 ; 81 : 197 – 204 .

Atia AN Buchman AL . Oral rehydration solutions in non-cholera diarrhea: a review . Am J Gastroenterol. 2009 ; 104 : 2596 – 2604 , quiz 2605.

Schoen EJ . Minimum urine total solute concentration in response to water loading in normal men . J Appl Physiol. 1957 ; 10 : 267 – 270 .

Sporn IN Lancestremere RG Papper S . Differential diagnosis of oliguria in aged patients . N Engl J Med. 1962 ; 267 : 130 – 132 .

Brenner BM , ed. Brenner and Rector's The Kidney , 8th edn. Philadelphia, PA: Saunders Elsevier ; 2007 .

Lindeman RD Van Buren HC Raisz LG . Osmolar renal concentrating ability in healthy young men and hospitalized patients without renal disease . N Engl J Med. 1960 ; 262 : 1306 – 1309 .

Shirreffs SM Maughan RJ . Control of blood volume: long term and short term regulation . In: Arnaud MJ , ed. Hydration Throughout Life . Montrouge: John Libbey Eurotext ; 1998 : 31 – 39 .

Schroeder C Bush VE Norcliffe LJ , et al . Water drinking acutely improves orthostatic tolerance in healthy subjects . Circulation. 2002 ; 106 : 2806 – 2811 .

Lu CC Diedrich A Tung CS , et al . Water ingestion as prophylaxis against syncope . Circulation. 2003 ; 108 : 2660 – 2665 .

Callegaro CC Moraes RS Negrao CE , et al . Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects . J Hum Hypertens. 2007 ; 21 : 564 – 570 .

Ando SI Kawamura N Matsumoto M , et al . Simple standing test predicts and water ingestion prevents vasovagal reaction in the high-risk blood donors . Transfusion. 2009 ; 49 : 1630 – 1636 .

Brick JE Lowther CM Deglin SM . Cold water syncope . South Med J. 1978 ; 71 : 1579 – 1580 .

Farb A Valenti SA . Swallow syncope . Md Med J. 1999 ; 48 : 151 – 154 .

Casella F Diana A Bulgheroni M , et al . When water hurts . Pacing Clin Electrophysiol. 2009 ; 32 : e25 – e27 .

Shirreffs SM Merson SJ Fraser SM Archer DT . The effects of fluid restriction on hydration status and subjective feelings in man . Br J Nutr. 2004 ; 91 : 951 – 958 .

Blau J . Water deprivation: a new migraine precipitant . Headache. 2005 ; 45 : 757 – 759 .

Blau JN Kell CA Sperling JM . Water-deprivation headache: a new headache with two variants . Headache. 2004 ; 44 : 79 – 83 .

Spigt MG Kuijper EC Schayck CP , et al . Increasing the daily water intake for the prophylactic treatment of headache: a pilot trial . Eur J Neurol. 2005 ; 12 : 715 – 718 .

Valtin H . “Drink at least eight glasses of water a day.” Really? Is there scientific evidence for “8 x 8”? Am J Physiol Regul Integr Comp Physiol. 2002 ; 283 : R993 – 1004 .

Negoianu D Goldfarb S . Just add water . J Am Soc Nephrol. 2008 ; 19 : 1041 – 1043 .

Madison KC . Barrier function of the skin: “la raison d'etre” of the epidermis . J Invest Dermatol. 2003 ; 121 : 231 – 241 .

Champion RH Burton JL Ebling FJG , eds. Textbook of Dermatology (Rook) . Oxford: Blackwell ; 1992 .

Vivanti A Harvey K Ash S Battistutta D . Clinical assessment of dehydration in older people admitted to hospital: what are the strongest indicators? Arch Gerontol Geriatr. 2008 ; 47 : 340 – 355 .

Colletti JE Brown KM Sharieff GQ Barata IA Ishimine P Committee APEM . The management of children with gastroenteritis and dehydration in the emergency department . J Emerg Med. 2009 .

Williams S Krueger N Davids M Kraus D Kerscher M . Effect of fluid intake on skin physiology: distinct differences between drinking mineral water and tap water . Int J Cosmet Sci. 2007 ; 29 : 131 – 138 .

Mac-Mary S Creidi P Marsaut D , et al . Assessment of effects of an additional dietary natural mineral water uptake on skin hydration in healthy subjects by dynamic barrier function measurements and clinic scoring . Skin Res Technol. 2006 ; 12 : 199 – 205 .

Warner RR Stone KJ Boissy YL . Hydration disrupts human stratum corneum ultrastructure . J Invest Dermatol. 2003 ; 120 : 275 – 284 .

Loden M . Role of topical emollients and moisturizers in the treatment of dry skin barrier disorders . Am J Clin Dermatol. 2003 ; 4 : 771 – 788 .

Manz F Wentz A . The importance of good hydration for the prevention of chronic diseases . Nutr Rev. 2005 ; 63 (Suppl): S2 – S5 .

Panel on Dietetic Products Nutrition and Allergies . Dietary reference values for water Scientific Opinion of the Panel on Dietetic Products, Nutrition and Allergies (Question No EFSA-Q-2005-015a) . EFSA J. 2009 ; 8 ( 3 ): 1459 .

Stookey JD Constant F Gardner C Popkin B . Replacing sweetened caloric beverages with drinking water is associated with lower energy intake . Obesity. 2007 ; 15 : 3013 – 3022 .

Stookey JD Constant F Gardner C Popkin BM . Drinking water is associated with weight loss . Obesity. 2008 ; 16 : 2481 – 2488 .

Turrini A Saba A Perrone D Cialfa E D'Amicis D . Food consumption patterns in Italy: the INN-CA Study 1994–1996 . Eur J Clin Nutr. 2001 ; 55 : 571 – 588 .

Sichert-Hellert W Kersting M Manz F . Fifteen year trends in water intake in German children and adolescents: results of the DONALD Study. Dortmund Nutritional and Anthropometric Longitudinally Designed Study . Acta Paediatr. 2001 ; 90 : 732 – 737 .

Raman A Schoeller DA Subar AF , et al . Water turnover in 458 American adults 40–79 yr of age . Am J Physiol Renal Physiol. 2004 ; 286 : F394 – F401 .

Daniels MC Popkin BM . The impact of water intake on energy intake and weight status: a review . Nutr Rev. 2010 ; 9 :in press.

Piernas C Popkin B . Snacking trends in U.S. adults between 1977 and 2006 . J Nutr . 2010 ; 140 : 325 – 332 .

Piernas C Popkin BM . Trends in snacking among U.S. children . Health Affairs. 2010 ; 29 : 398 – 404 .

Popkin BM Duffey KJ. Does hunger and satiety drive eating anymore? Increasing eating occasions and decreasing time between eating occasions in the United States . Am J Clin Nutr . 2010 ; 91 : 1342 – 1347 .

Muckelbauer R Libuda L Clausen K Toschke AM Reinehr T Kersting M . Promotion and provision of drinking water in schools for overweight prevention: randomized, controlled cluster trial . Pediatrics. 2009 ; 123 : e661 – e667 .

Bar-or O . Temperature regulation during exercise in children and aolescents . In: Gisolfi C Lamb DR , eds. Youth, Exercise, and Sport: Symposium: Papers and Discussions . Indianapolis: Benchmark ; 1989 : 335 – 367 .

National Research Council . Recommended Dietary Allowances . Washington, DC: National Academy Press ; 1989 .

Prentice A Branca F Decsi T , et al . Energy and nutrient dietary reference values for children in Europe: methodological approaches and current nutritional recommendations . Br J Nutr. 2004 ; 92 (Suppl 2 ): S83 – 146 .

German Nutrition Society, Austrian Nutrition Society, Swiss Society for Nutrition Research Swiss Nutrition Association . Reference Values for Nutrient Intake (in English) , 1st edn. Frankfurt: Umschau Brau ; 2002 .

Stookey JD Pieper CF Cohen HJ . Is the prevalence of dehydration among community-dwelling older adults really low? Informing current debate over the fluid recommendation for adults aged 70+years . Public Health Nutr. 2005 ; 8 : 1275 – 1285 .

Malik VS Popkin BM Bray G Després J-P Hu FB. Sugar sweetened beverages, obesity, type 2 diabetes and cardiovascular disease risk . Circulation 2010 ; 121 : 1356 – 1364 .

Teff KL Grudziak J Townsend RR , et al . Endocrine and metabolic effects of consuming fructose- and glucose-sweetened beverages with meals in obese men and women: influence of insulin resistance on plasma triglyceride responses . J Clin Endocrinol Metab. 2009 ; 94 : 1562 – 1569 .

Stanhope KL . Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans . J Clin Investigat. 2009 ; 119 : 1322 – 1334 .

Stanhope KL Havel PJ . Endocrine and metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose, or high-fructose corn syrup . Am J Clin Nutr. 2008 ; 88 (Suppl): S1733 – S1737 .

Stanhope KL Griffen SC Bair BR Swarbrick MM Keim NL Havel PJ . Twenty-four-hour endocrine and metabolic profiles following consumption of high-fructose corn syrup-, sucrose-, fructose-, and glucose-sweetened beverages with meals . Am J Clin Nutr. 2008 ; 87 : 1194 – 1203 .

Altman P . Blood and Other Body Fluids . Washington, DC: Federation of American Societies for Experimental Biology ; 1961 .

Kalhoff H . Mild dehydration: a risk factor of broncho-pulmonary disorders? Eur J Clin Nutr. 2003 ; 57 (Suppl 2 ): S81 – S87 .

Taitz LS Byers HD . High calorie-osmolar feeding and hypertonic dehydration . Arch Dis Child. 1972 ; 47 : 257 – 260 .

Burge MR Garcia N Qualls CR Schade DS . Differential effects of fasting and dehydration in the pathogenesis of diabetic ketoacidosis . Metabolism. 2001 ; 50 : 171 – 177 .

Jayashree M Singhi S . Diabetic ketoacidosis: predictors of outcome in a pediatric intensive care unit of a developing country . Pediatr Crit Care Med. 2004 ; 5 : 427 – 433 .

Hebert LA Greene T Levey A Falkenhain ME Klahr S . High urine volume and low urine osmolality are risk factors for faster progression of renal disease . Am J Kidney Dis. 2003 ; 41 : 962 – 971 .

Bankir L Bardoux P Mayaudon H Dupuy O Bauduceau B . [Impaired urinary flow rate during the day: a new factor possibly involved in hypertension and in the lack of nocturnal dipping] . Arch Mal Coeur Vaiss. 2002 ; 95 : 751 – 754 .

Blanker MH Bernsen RM Ruud Bosch JL , et al . Normal values and determinants of circadian urine production in older men: a population based study . J Urol. 2002 ; 168 : 1453 – 1457 .

Chan J Knutsen SF Blix GG Lee JW Fraser GE . Water, other fluids, and fatal coronary heart disease: the Adventist Health Study . Am J Epidemiol. 2002 ; 155 : 827 – 833 .

Kelly J Hunt BJ Lewis RR , et al . Dehydration and venous thromboembolism after acute stroke . QJM. 2004 ; 97 : 293 – 296 .

Bhalla A Sankaralingam S Dundas R Swaminathan R Wolfe CD Rudd AG . Influence of raised plasma osmolality on clinical outcome after acute stroke . Stroke. 2000 ; 31 : 2043 – 2048 .

Longo-Mbenza B Phanzu-Mbete LB M'Buyamba-Kabangu JR , et al . Hematocrit and stroke in black Africans under tropical climate and meteorological influence . Ann Med Interne (Paris). 1999 ; 150 : 171 – 177 .

Diamond PT Gale SD Evans BA . Relationship of initial hematocrit level to discharge destination and resource utilization after ischemic stroke: a pilot study . Arch Phys Med Rehabil. 2003 ; 84 : 964 – 967 .

Mazzola BL von Vigier RO Marchand S Tonz M Bianchetti MG . Behavioral and functional abnormalities linked with recurrent urinary tract infections in girls . J Nephrol. 2003 ; 16 : 133 – 138 .

Wilde MH Carrigan MJ . A chart audit of factors related to urine flow and urinary tract infection . J Adv Nurs. 2003 ; 43 : 254 – 262 .

Altieri A La Vecchia C Negri E . Fluid intake and risk of bladder and other cancers . Eur J Clin Nutr. 2003 ; 57 (Suppl 2 ): S59 – S68 .

Donat SM Bayuga S Herr HW Berwick M . Fluid intake and the risk of tumor recurrence in patients with superficial bladder cancer . J Urol. 2003 ; 170 : 1777 – 1780 .

Radosavljevic V Jankovic S Marinkovic J Djokic M . Fluid intake and bladder cancer. A case control study . Neoplasma. 2003 ; 50 : 234 – 238 .

Math MV Rampal PM Faure XR Delmont JP . Gallbladder emptying after drinking water and its possible role in prevention of gallstone formation . Singapore Med J. 1986 ; 27 : 531 – 532 .

Aufderheide S Lax D Goldberg SJ . Gender differences in dehydration-induced mitral valve prolapse . Am Heart J. 1995 ; 129 : 83 – 86 .

Martin B Harris A Hammel T Malinovsky V . Mechanism of exercise-induced ocular hypotension . Invest Ophthalmol Vis Sci. 1999 ; 40 : 1011 – 1015 .

Brucculeri M Hammel T Harris A Malinovsky V Martin B . Regulation of intraocular pressure after water drinking . J Glaucoma. 1999 ; 8 : 111 – 116 .

• dehydration
• energy intake
• water drinking
• fluid intake
• water requirements

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Drinking Water Quality and Public Health

• S.I.: Drinking Water Quality and Public Health
• Published: 04 February 2019
• Volume 11 , pages 73–79, ( 2019 )

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• Peiyue Li   ORCID: orcid.org/0000-0001-8771-3369 1 , 2 &
• Jianhua Wu 1 , 2  

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Drinking water quality is one of the greatest factors affecting human health. However, drinking water quality in many countries, especially in developing countries is not desirable and poor drinking water quality has induced many waterborne diseases. This special issue of Exposure and Health was edited to gain a better understanding of the impacts of drinking water quality on public health so that proper actions can be taken to improve the drinking water quality conditions in many countries. This editorial introduction reviewed some latest research on drinking water quality and public health, summarized briefly the main points of each contribution in this issue, and then some research fields/directions were proposed to boost further scientific research in drinking water quality and public health. The papers in this issue are interesting and cover many aspects of this research topic, and will be meaningful for the sustainable drinking water quality protection.

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Abbasi T, Abbasi SA (2012) Water quality indices. Elsevier, Amsterdam

Google Scholar  

Abtahi M, Golchinpour N, Yaghmaeian K, Rafiee M, Jahangiri-rad M, Keyani A, Saeedi R (2015) A modified drinking water quality index (DWQI) for assessing drinking source water quality in rural communities of Khuzestan Province, Iran. Ecol Indic 53:283–291. https://doi.org/10.1016/j.ecolind.2015.02.009

Article   CAS   Google Scholar  

Abtahi M, Yaghmaeian K, Mohebbi MR, Koulivand A, Rafiee M, Jahangiri-rad M, Jorfi S, Saeedi R, Oktaie S (2016) An innovative drinking water nutritional quality index (DWNQI) for assessing drinking water contribution to intakes of dietary elements: a national and sub-national study in Iran. Ecol Indic 60:367–376. https://doi.org/10.1016/j.ecolind.2015.07.004

Adimalla N (2018) Groundwater quality for drinking and irrigation purposes and potential health risks assessment: a case study from semi-Arid region of south India. Expo Health. https://doi.org/10.1007/s12403-018-0288-8

Article   Google Scholar  

Adimalla N, Li P (2018) Occurrence, health risks and geochemical mechanisms of fluoride and nitrate in groundwater of the rock-dominant semi-arid region, Telangana State, India. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2018.1480353

Adimalla N, Wu J (2019) Groundwater quality and associated health risks in a semi-arid region of south India: Implication to sustainable groundwater management. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2018.1546550

Ahmed MF, Mokhtar MB, Alam L, Mohamed CAR, Ta GC (2019) Non-carcinogenic health risk assessment of aluminium ingestion via drinking water in Malaysia. Expo Health. https://doi.org/10.1007/s12403-019-00297-w

Akter T, Jhohura FT, Akter F, Chowdhury TR, Mistry SK, Dey D, Barua MK, Islam MA, Rahman M (2016) Water Quality Index for measuring drinking water quality in rural Bangladesh: a cross-sectional study. J Health Popul Nutr 35:4. https://doi.org/10.1186/s41043-016-0041-5

Ali N, Kalsoom Khan S, Ihsanullah Rahman IU, Muhammad S (2018) Human health risk assessment through consumption of organophosphate pesticide-contaminated water of peshawar basin, Pakistan. Expo Health 10:259–272. https://doi.org/10.1007/s12403-017-0259-5

Buytaert W, Dewulf A, Bièvre BD, Clark J, Hannah DM (2016) Citizen Science for Water Resources Management: Toward Polycentric Monitoring and Governance? J Water Resour Plann Manag 142(4):01816002. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000641

Chen J, Qian H, Gao Y, Li X (2018) Human Health Risk Assessment of Contaminants in Drinking Water Based on Triangular Fuzzy Numbers Approach in Yinchuan City, Northwest China. Expo Health 10:155–166. https://doi.org/10.1007/s12403-017-0252-z

Deng Q, Chen L, Wei Y, Li Y, Han X, Liang W, Zhao Y, Wang X, Yin J (2018) Understanding the association between environmental factors and longevity in Hechi, China: a drinkingwater and soil quality perspective. Int J Environ Res Public Health 15(10):2272. https://doi.org/10.3390/ijerph15102272

Dey NC, Parvez M, Saha R, Islam MR, Akter T, Rahman M, Barua M, Islam A (2018) Water quality and willingness to pay for safe drinking water in Tala Upazila in a coastal district of bangladesh. Expo Health. https://doi.org/10.1007/s12403-018-0272-3

Farnham DJ, Gibson RA, Hsueh DY, McGillis WR, Culligan PJ, Zain N, Buchanan R (2017) Citizen science-based water quality monitoring: constructing a large database to characterize the impacts of combined sewer overflow in New York City. Sci Total Environ 580:168–177. https://doi.org/10.1016/j.scitotenv.2016.11.116

Gara T, Li F, Nhapi I, Makate C, Gumindoga W (2018) Health safety of drinking water supplied in africa: a closer look using applicable water-quality standards as a measure. Expo Health 10:117–128. https://doi.org/10.1007/s12403-017-0249-7

Gavrilescu M, DemnerováK Aamand J, Agathos S, Fava F (2015) Emerging pollutants in the environment: present and future challenges in biomonitoring, ecological risks and bioremediation. New Biotechnol 32(1):147–156. https://doi.org/10.1016/j.nbt.2014.01.001

Hartmann J, Van der Aa M, Wuijts S, De Roda Husman AM, Van der Hoek JP (2018) Risk governance of potential emerging risks to drinking water quality: analysing current practices. Environ Sci Policy 84:97–104. https://doi.org/10.1016/j.envsci.2018.02.015

He S, Wu J (2018) Hydrogeochemical characteristics, groundwater quality, and health risks from hexavalent chromium and nitrate in groundwater of Huanhe formation in Wuqi County, Northwest China. Expo Health. https://doi.org/10.1007/s12403-018-0289-7

He S, Wu J (2019) Relationships of groundwater quality and associated health risks with land use/land cover patterns: a case study in a loess area, northwest China. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2019.1570463

He X, Wu J, He S (2018) Hydrochemical characteristics and quality evaluation of groundwater in terms of health risks in Luohe aquifer in Wuqi County of the Chinese Loess Plateau, northwest China. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2018.1531693

He X, Wu J, Guo W (2019) Karst spring protection for the sustainable and healthy living: the examples of Niangziguan spring and Shuishentang spring in Shanxi, China. Expo Health. https://doi.org/10.1007/s12403-018-00295-4

Jabed MA, Paul A, Nath TK (2018) Peoples’ perception of the water salinity impacts on human health: a case study in South-Eastern coastal region of Bangladesh. Expo Health. https://doi.org/10.1007/s12403-018-0283-0

Jessoe K (2013) Improved source, improved quality? Demand for drinking water quality in rural India. J Environ Econ Manag 66:460–475. https://doi.org/10.1016/j.jeem.2013.05.001

Jollymore A, Haines MJ, Satterfield T, Johnson MS (2017) Citizen science for water quality monitoring: Data implications of citizen perspectives. J Environ Manag 200:456–467. https://doi.org/10.1016/j.jenvman.2017.05.083

Joshi YP, Kim J-H, Kim H, Cheong H-K (2018) Impact of drinking water quality on the development of enteroviral diseases in Korea. Int J Environ Res Public Health 15(11):2551. https://doi.org/10.3390/ijerph15112551

Kumar D, Singh A, Jha RK, Sahoo SK, Jha V (2019) A variance decomposition approach for risk assessment of groundwater quality. Expo Health. https://doi.org/10.1007/s12403-018-00293-6

Li P (2016) Groundwater quality in western China: challenges and paths forward for groundwater quality research in western China. Expo Health 8(3):305–310. https://doi.org/10.1007/s12403-016-0210-1

Li P (2018) Mine water problems and solutions in China. Mine Water Environ 37(2):217–221. https://doi.org/10.1007/s10230-018-0543-z

Li P, Qian H (2018a) Water resource development and protection in loess areas of the world: a summary to the thematic issue of water in loess. Environ Earth Sci 77(24):796. https://doi.org/10.1007/s12665-018-7984-3

Li P, Qian H (2018b) Water resources research to support a sustainable China. Int J Water Res Dev 34(3):327–336. https://doi.org/10.1080/07900627.2018.1452723

Li P, Qian H, Wu J, Zhang Y, Zhang H (2013) Major ion chemistry of shallow groundwater in the Dongsheng coalfield, Ordos Basin, China. Mine Water Environ 32(3):195–206. https://doi.org/10.1007/s10230-013-0234-8

Li P, Li X, Meng X, Li M, Zhang Y (2016) Appraising groundwater quality and health risks from contamination in a semiarid region of northwest China. Expo Health 8(3):361–379. https://doi.org/10.1007/s12403-016-0205-y

Li P, Qian H, Zhou W (2017a) Finding harmony between the environment and humanity: an introduction to the thematic issue of the Silk Road. Environ Earth Sci 76(3):105. https://doi.org/10.1007/s12665-017-6428-9

Li P, Feng W, Xue C, Tian R, Wang S (2017b) Spatiotemporal variability of contaminants in lake water and their risks to human health: a case study of the Shahu Lake tourist area, northwest China. Expo Health 9(3):213–225. https://doi.org/10.1007/s12403-016-0237-3

Li P, Tian R, Xue C, Wu J (2017c) Progress, opportunities and key fields for groundwater quality research under the impacts of human activities in China with a special focus on western China. Environ Sci Pollut Res 24(15):13224–13234. https://doi.org/10.1007/s11356-017-8753-7

Li P, He S, He X, Tian R (2018a) Seasonal hydrochemical characterization and groundwater quality delineation based on matter element extension analysis in a paper wastewater irrigation area, northwest China. Expo Health 10(4):241–258. https://doi.org/10.1007/s12403-17-0258-6

Li P, He S, Yang N, Xiang G (2018b) Groundwater quality assessment for domestic and agricultural purposes in Yan’an City, northwest China: implications to sustainable groundwater quality management on the Loess Plateau. Environ Earth Sci 77(23):775. https://doi.org/10.1007/s12665-2018-7968-3

Li P, He X, Li Y, Xiang G (2018c) Occurrence and health implication of fluoride in groundwater of loess aquifer in the Chinese Loess Plateau: a case study of Tongchuan, northwest China. Expo Health. https://doi.org/10.1007/s12403-018-0278-x

Li P, Wu J, Tian R, He S, He X, Xue C, Zhang K (2018d) Geochemistry, hydraulic connectivity and quality appraisal of multilayered groundwater in the Hongdunzi coal mine, northwest China. Mine Water Environ 37(2):222–237. https://doi.org/10.1007/s10230-017-0507-8

Li P, Tian R, Liu R (2018e) Solute geochemistry and multivariate analysis of water quality in the Guohua phosphorite mine, Guizhou Province, China. Expo Health. https://doi.org/10.1007/s12403-018-0277-y

Li P, Qian H, Wu J (2018f) Conjunctive use of groundwater and surface water to reduce soil salinization in the Yinchuan Plain, north-west China. Int J Water Resour Dev 34(3):337–353. https://doi.org/10.1080/07900627.2018.1443059

Li P, He X, Guo W (2019) Spatial groundwater quality and potential health risks due to nitrate ingestion through drinking water: a case study in Yan’an City on the Loess Plateau of northwest China. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2018.1553612

Long DT, Pearson AL, Voice TC, Polanco-Rodríguez AG, Sanchez-Rodríguez EC, Xagoraraki I, Concha-Valdez FG, Puc-Franco M, Lopez-Cetz R, Rzotkiewicz AT (2018) Influence of rainy season and land use on drinking water quality in a karst landscape, State of Yucatán, Mexico. Appl Geochem 98:265–277. https://doi.org/10.1016/j.apgeochem.2018.09.020

McKinley DC, Miller-Rushing AJ, Ballard HL, Bonney R, Brown H, Cook-Patton SC, Evans DM, French RA, Parrish JK, Phillips TB, Ryan SF, Shanley LA, Shirk JL, Stepenuck KF, Weltzin JF, Wiggins A, Boyle OD, Briggs RD, Chapin SF, Hewitt DA, Preuss PW, Soukup MA (2017) Citizen science can improve conservation science, natural resource management, and environmental protection. Biol Conserv 208:15–28. https://doi.org/10.1016/j.biocon.2016.05.015

Mitra P, Pal DK, Das M (2018) Does quality of drinking water matter in kidney stone disease: a study in West Bengal. India. Investigative and Clinical Urology 59(3):158–165. https://doi.org/10.4111/icu.2018.59.3.158

Njinga RL, Tshivhase VM (2017) Major Chemical Carcinogens in Drinking Water Sources: Health Implications Due to Illegal Gold Mining Activities in Zamfara State-Nigeria. Expo Health. https://doi.org/10.1007/s12403-017-0265-7

Prusty P, Farooq SH, Zimik HV, Barik SS (2018) Assessment of the factors controlling groundwater quality in a coastal aquifer adjacent to the Bay of Bengal. India. Environ Earth Sci 77:762. https://doi.org/10.1007/s12665-018-7943-z

Rusca M, Boakye-Ansah AS, Loftus A, Ferrero G, Van der Zaag P (2017) An interdisciplinary political ecology of drinking water quality. Exploring socio-ecological inequalities in Lilongwe’s water supply network. Geoforum 84:138–146. https://doi.org/10.1016/j.geoforum.2017.06.013

Scheili A, Rodriguez MJ, Sadiqb R (2015) Seasonal and spatial variations of source and drinking water quality in small municipal systems of two Canadian regions. Sci Total Environ 508:514–524. https://doi.org/10.1016/j.scitotenv.2014.11.069

Scheili A, Rodriguez MJ, Sadiq R (2016a) Impact of human operational factors on drinking water quality in small systems: an exploratory analysis. J Clean Prod 133:681–690. https://doi.org/10.1016/j.jclepro.2016.05.179

Scheili A, Delpla I, Sadiq R, Rodriguez MJ (2016b) Impact of raw water quality and climate factors on the variability of drinking water quality in small systems. Water Resour Manage 30:2703–2718. https://doi.org/10.1007/s11269-016-1312-z

Soldatova E, Sun Z, Maier S, Drebot V, Gao B (2018) Shallow groundwater quality and associated non-cancer health risk in agricultural areas (Poyang Lake basin, China). Environ Geochem Health 40:2223–2242. https://doi.org/10.1007/s10653-018-0094-z

Su F, Wu J, He S (2019) Set pair analysis (SPA)-Markov chain model for groundwater quality assessment and prediction: a case study of Xi’an City, China. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2019.1568860

Tian R, Wu J (2019) Groundwater quality appraisal by improved set pair analysis with game theory weightage and health risk estimation of contaminants for Xuecha drinking water source in a loess area in Northwest China. Hum Ecol Risk Assess. https://doi.org/10.1080/10807039.2019.1573035

Vishwakarma CA, Sen R, Singh N, Singh P, Rena V, Rina K, Mukherjee S (2018) Geochemical characterization and controlling factors of chemical composition of spring water in a part of Eastern Himalaya. J Geol Soc India 92:753–763. https://doi.org/10.1007/s12594-018-1098-0

Wang W, Qiang Y, Wang Y, Sun Q, Zhang M (2016) Impacts of yuyang coal mine on groundwater quality in Hongshixia water source, Northwest China: a physicochemical and modeling research. Expo Health 8(3):431–442. https://doi.org/10.1007/s12403-016-0223-9

WHO (2018) Drinking-water. World Health Organization fact sheets, https://www.who.int/en/news-room/fact-sheets/detail/drinking-water , Accessed 27 Dec 2018

Wu J, Sun Z (2016) Evaluation of shallow groundwater contamination and associated human health risk in an alluvial plain impacted by agricultural and industrial activities, mid-west China. Expo Health 8(3):311–329. https://doi.org/10.1007/s12403-015-0170-x

Wu J, Li P, Qian H, Duan Z, Zhang X (2014) Using correlation and multivariate statistical analysis to identify hydrogeochemical processes affecting the major ion chemistry of waters: Case study in Laoheba phosphorite mine in Sichuan. China. Arab J Geosci 7(10):3973–3982. https://doi.org/10.1007/s12517-013-1057-4

Wu J, Wang L, Wang S, Tian R, Xue C, Feng W, Li Y (2017) Spatiotemporal variation of groundwater quality in an arid area experiencing long-term paper wastewater irrigation, northwest China. Environ Earth Sci 76(13):460. https://doi.org/10.1007/s12665-017-6787-2

Wuijts S, Driessen PPJ, Van Rijswick HFMW (2018) Governance conditions for improving quality drinking water resources: the need for enhancing connectivity. Water Resour Manag 32:1245–1260. https://doi.org/10.1007/s11269-017-1867-3

Zhang Y, Wu J, Xu B (2018a) Human health risk assessment of groundwater nitrogen pollution in Jinghui canal irrigation area of the loess region, northwest China. Environ Earth Sci 77(7):273. https://doi.org/10.1007/s12665-018-7456-9

Zhang H, Zhou X, Wang L, Wang W, Xu J (2018b) Concentrations and potential health risks of strontium in drinking water from Xi'an, Northwest China. Ecotoxicol Environ Saf 164:181–188. https://doi.org/10.1016/j.ecoenv.2018.08.017

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Acknowledgements

Prof. Andrew Meharg, the Editor in Chief of Exposure and Health and Fritz Schmuhl, the Publishing Editor are sincerely acknowledged for their approval and support on this special issue. The publisher and the entire editorial team are strong, making the publication smooth and quick. It is one of the top editorial teams in the publishing community. We are greatly grateful to contributors whose manuscripts have been rejected and those whose manuscripts have been published in this special issue, and many reviewers are also acknowledged. Without interested authors and without voluntary reviewers, it would be impossible to publish this special issue. We are also grateful to various funding agencies and organizations who have provided financial support to our research, and they are the National Natural Science Foundation of China (41502234, 41602238, 41572236 and 41761144059), the Research Funds for Young Stars in Science and Technology of Shaanxi Province (2016KJXX-29), the Special Funds for Basic Scientific Research of Central Colleges (300102298301), the Fok Ying Tong Education Foundation (161098), the General Financial Grant from the China Postdoctoral Science Foundation (2015M580804 and 2016M590911), the Special Financial Grant from the China Postdoctoral Science Foundation (2016T090878 and 2017T100719), the Special Financial Grant from the Shaanxi Postdoctoral Science Foundation (2015BSHTDZZ09 and 2015BSHTDZZ03), and the Ten Thousand Talents Program.

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Li, P., Wu, J. Drinking Water Quality and Public Health. Expo Health 11 , 73–79 (2019). https://doi.org/10.1007/s12403-019-00299-8

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Peer-reviewed

Research Article

Microplastic contamination of drinking water: A systematic review

Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Visualization, Writing – original draft, Writing – review & editing

* E-mail: [email protected]

Affiliation Hull York Medical School, University of Hull, Hull, United Kingdom

Roles Project administration, Supervision, Validation, Writing – review & editing

Roles Funding acquisition, Project administration, Supervision, Writing – review & editing

Affiliation Department of Biological and Marine Sciences, University of Hull, Hull, United Kingdom

• Evangelos Danopoulos, 
• Maureen Twiddy, 
• Jeanette M. Rotchell

• Published: July 31, 2020
• https://doi.org/10.1371/journal.pone.0236838
• Reader Comments

Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.

To undertake a systematic review of MP contamination of drinking water and estimate quantitative exposures.

The protocol for the systematic review employed has been published in PROSPERO (PROSPERO 2019, Registration number: CRD42019145290). MEDLINE, EMBASE and Web of Science were searched from launch to the 3rd of June 2020, selecting studies that used procedural blank samples and a validated method for particle composition analysis. Studies were reviewed within a narrative analysis. A bespoke risk of bias (RoB) assessment tool was used.

12 studies were included in the review: six of tap water (TW) and six of bottled water (BW). Meta-analysis was not appropriate due to high statistical heterogeneity (I 2 >95%). Seven studies were rated low RoB and all confirmed MP contamination of drinking water. The most common polymers identified in samples were polyethylene terephthalate (PET) and polypropylene (PP), Methodological variability was observed throughout the experimental protocols. For example, the minimum size of particles extracted and analysed, which varied from 1 to 100 μm, was seen to be critical in the data reported. The maximum reported MP contamination was 628 MPs/L for TW and 4889 MPs/L for BW, detected in European samples. Based on typical consumption data, this may be extrapolated to a maximum yearly human adult uptake of 458,000 MPs for TW and 3,569,000 MPs for BW.

Conclusions

This is the first systematic review that appraises the quality of existing evidence on MP contamination of drinking water and estimates human exposures. The precautionary principle should be adopted to address concerns on possible human health effects from consumption of MPs. Future research should aim to standardise experimental protocols to aid comparison and elevate quality.

Citation: Danopoulos E, Twiddy M, Rotchell JM (2020) Microplastic contamination of drinking water: A systematic review. PLoS ONE 15(7): e0236838. https://doi.org/10.1371/journal.pone.0236838

Editor: Amitava Mukherjee, VIT University, INDIA

Received: May 1, 2020; Accepted: July 14, 2020; Published: July 31, 2020

Copyright: © 2020 Danopoulos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: This research is supported by a PhD scholarship to ED within the “Health Inequalities and emerging environmental contaminants – Places and People” cluster funded by the University of Hull. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Microplastics (MPs) are particles of predominantly synthetic polymeric composition in the micro scale [ 1 , 2 ], and while a consensus on size range has not been reached, the typical range is between 1 μm and 5 mm. MPs have been identified in all aquatic environments: marine [ 3 – 7 ] and freshwater (lakes, rivers, reservoirs, groundwater) [ 8 – 15 ], but research has so far concentrated more on marine environments. MP contamination of aquatic environments is expected to rise, hand-in-hand with the continuous rise in plastic production, use and waste [ 16 – 20 ]. MPs have also entered the food web, thus becoming an emerging food safety issue and risk [ 21 – 25 ]. Emerging risk in terms of food safety is defined as a risk posed by possible significant exposures to a recently identified (emerging) hazard [ 26 , 27 ].

Human exposure pathways include ingestion and inhalation and the presence of MPs in human stool samples has recently been verified [ 28 ]. Drinking water is considered as one possible medium for the introduction of MPs into the human body [ 24 ]. There is a growing interest around the prevalence of MPs in drinking water underpinned by recent research but a systematic review of available evidence is lacking [ 29 – 35 ]. None of the existing reviews have used the methodology [ 36 ] on which systematic reviews are based. Systematic reviews synthesize the findings quantitatively and qualitatively in a standardised way, avoiding the introduction of bias. Although human health effects are still under examination, lessons from toxicology inform us that the effects will be dose dependent [ 37 – 39 ]. Determining exposure levels is key in formulating a risk assessment framework for this emerging environmental contaminant. Health effects will be caused by: their physical attributes, the chemical properties of the polymers, the plasticisers, or other chemicals added in the manufacturing process, and the chemicals they can absorb in nature as well as the microbes that can grow on their surface [ 40 – 42 ].

This review focuses on water intended for human consumption, including tap water (TW) that is available to consumers via water treatment plants (WTP) and bottled water (BW). BW is further divided into table, spring and natural mineral water. Specific regulations govern their categorization according to their source and the processes that they are allowed to undergo before being bottled [e.g. 43 – 45 ]. Both natural mineral and spring water come from underground water sources, in principle, protected from pollution and are bottled in situ . In contrast, bottled table water can come from any source, including municipal mains (tap water), as long as it conforms to water safety specifications [ 43 ]. Water from different categories will vary in quality depending on the initial water quality, and the processes they are subjected to ensure food safety, transportation and packaging.

The aim of this review was to identify all available research on MP contamination of drinking waters and assess their quality to determine the state of the evidence and consequently, attempt quantification of human exposures in the prism of an emerging food safety issue. We also aim to compare water of different origins (TW and BW) in terms of MP contamination load. Further, we address the methodological issues in the field of environmental MPs research regarding study design, execution and reporting.

This review follows a protocol published in PROSPERO (PROSPERO 2019, Registration number: CRD42019145290) available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019145290 and in the S1 Protocol (available in the Supporting Information). The protocol was developed according to the guidelines set by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocols (PRISMA-P) [ 46 , 47 ]. The protocol was designed to include available research on all food categories which were determined by a preceding scoping review. In brief, only descriptive and analytic observational study designs (and not experimental) were included [ 48 ]. No time limit on publication date was set and databases were searched from launch date to 10 th July 2019. The searches were repeated on the 3rd of June 2020 to include the most recently published papers. Only studies that reported on ‘water intended for human consumption’ as defined by Directive 2009/54/EC [ 44 ] and Regulation (EC) No 178 [ 49 ] were included. Eligible studies must have used one (or more) of the four currently validated processes for the identification of microparticle composition: Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy (RM), pyrolysis gas chromatography/ mass spectrometry (Pyr-GC-MS) and scanning electron microscopy plus energy-dispersive X-ray spectroscopy (SEM/EDS). The use of procedural blank samples was also mandatory. Articles that were not published in the English language were excluded.

Information sources were MEDLINE (OVID interface, 1946 onwards), EMBASE (OVID interface, 1974 onwards) and the Web of Science core collection (Web of Science, 1900 onwards). The search strategy was developed for MEDLINE and EMBASE (OVID interface) using free text and MeSH, for all food categories. Search terms included: microplastic, nanoplastic, food contamination, water contamination (full search strategy can be found in S1 Table ). Study selection was executed using a two-level screening by two independent reviewers against the inclusion/exclusion criteria. Any discrepancies were resolved by a third-party arbitrator. Inter-rater agreement level for the first level screening was 90%, Cohen’s k: 0.34, and for the second level: 100%, Cohen’s k: 1 [ 50 ]. A form previously developed and verified for a scoping review was used for data extraction.

The quality of the studies was assessed with the use of a bespoke risk of bias (RoB) assessment tool, which was developed because the existing tools were not suitable for the scope of the review [ 51 ]. Assessment tool development was based on guidelines set by the Centre for Reviews and Dissemination [ 52 ], the STROBE Statement checklist [ 53 ], the Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services [ 54 ], the Environmental-Risk of Bias Tool [ 55 ] regarding evidence in environmental science and the Cochrane Collaboration’s tool for assessing RoB [ 56 ]. The RoB tool, is a checklist ( S2 Table ), that prompts questions across four domains: study design, sampling, analysis and reporting, leading to an overall assessment with justification for each entry [ 57 ]. There were three ratings: high risk, low risk or unclear RoB and the results were used to assess study quality and overall certainty of evidence.

The primary outcome of interest was MP content in the sample expressed in a quantitative measure in any available units of measurements. Further information of interest included the methodological specifications of the experimental protocols. The studies were reviewed in a narrative analysis according to the guidelines set down by the Centre for Reviews and Dissemination [ 52 ] and the results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement [ 58 , 59 ] ( S1 PRISMA Checklist ).

Study selection

2467 citations were identified by the search strategy, after duplicates were removed, and 2307 citations were dismissed in the first-level screening based on their title and abstract ( Fig 1 ). During the second-level screening, the full papers were scrutinized, and 112 studies were removed with reasons ( S1 Appendix ) and seven were included. When the searches were re-run, five more studies were included after the first and second level screening ( Fig 1 ), resulting in 12 studies [ 60 – 71 ] finally included in this systematic review.

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The flow chart presents the results and screening process of the original searches and the rerun of the searches.

https://doi.org/10.1371/journal.pone.0236838.g001

Study characteristics

All the studies included analysed water readily available for human consumption. The study characteristics are presented in S3 Table . Six studies used samples of BW (table and mineral) and six studies used TW. The overall sample size for BW was n = 91 brands (n = 435 bottles) and for the TW, n = 155 samples. All of the studies used different techniques to extract particles from their samples. One study used FTIR [ 61 ], three studies used m-FTIR [ 62 , 67 , 70 ], one study used RM [ 68 ], four used m-RM [ 63 , 65 , 66 , 69 ], one both FTIR and RM [ 60 ], one used both m-FTIR and m-RM [ 64 ] and one SEM-EDX [ 71 ] to identify the composition of the extracted particles. Ten of the studies reported the results by MP particles per volume, one provides only the range of MP content and one the frequency of occurrence.

Risk of bias within studies

RoB was assessed in a systematic way using the RoB tool created for this review. The results of the assessment are illustrated in Figs 2 and 3 . Two studies were assessed as of high RoB [ 69 , 71 ] and three of unclear RoB [ 66 – 68 ]. The RoB assessment is used in the analysis part of the review.

The figure shows the rating for the four domains and the overall rating for each study. Red (-) indicates high RoB, green (+) indicates low RoB and yellow (?) indicates unclear RoB (Unclear RoB is given to a study when substantial information to make an informed assessment have not been reported).

https://doi.org/10.1371/journal.pone.0236838.g002

https://doi.org/10.1371/journal.pone.0236838.g003

Results of MPs contamination

The results are presented in Table 1 as two categories of TW and BW. The results from Mintenig et al. [ 62 ] were converted from MPs/m 3 to MPs/L content for ease of comparison to the remaining studies. Mason et al. [ 61 ] divided the results in two sections: one including particles ≥100 μm that were verified as MPs through FTIR spectral analysis and particles <100 μm that were only tagged using Nile Red solution to dye them. In line with our eligibility criteria, only the results of the FTIR verified particles will be included in this review. Visual observation for the identification of MP particles can lead to under or overestimations [ 31 ]. The use of instruments which identify the chemical composition in a standardized way based on a physical or electronic output (spectra, pyrograms etc.) exclude the introduction of human error and enable reproducibility and transparency of the results.

https://doi.org/10.1371/journal.pone.0236838.t001

Regarding studies other than BW, when results were presented for both untreated and treated water, only the latter are presented.

Six studies [ 62 , 64 , 66 – 68 , 70 ] sampled and analysed TW that was readily available to consumers via a public service. The percentage of samples containing MPs across the studies ranged from 24% to 100% and the MPs content from 0–1247 MPs/L. The most common shapes identified were fragments and second most common was fibres. A key difference between the samples is that Pivokonsky et al. [ 64 ] used water coming from surface waters (reservoirs), which are open aquatic systems exposed to contamination, while Mintenig et al. [ 62 ] used water from underground and therefore protected sources. Shruti et al. [ 66 ] used water from a variety of sources but the majority came from local aquifers. Strand et al. [ 67 ], Tong et al. [ 68 ] and Zhang et al. [ 70 ] did not provide information on the origin of the water. It is reasonable to assume that water quality before it entered the WTP would vary and directly affect the quality of the water after processing [ 8 ].

Four of the studies [ 64 , 66 , 68 , 70 ] provided the necessary data to attempt a meta-analysis. In order to test whether the results were appropriate for meta-analysis, the statistical heterogeneity was measured using a Higgins I 2 test [ 72 ], calculated using R (version 3.6.0) [ 73 ], executing all analysis via RStudio, (version 1.2.1335) [ 74 ], and using the additional packages meta (version 4.9–7) [ 75 ], metaphor (version 2.1–0) [ 76 ], dmetar [ 77 ], robvis [ 78 ] and ggplot2 [ 79 ]. A random-effects model was fitted [ 80 , 81 ] and heterogeneity was found to be high, I 2 = 99.8% (see forest plot in S1 Fig ). In order to detect the origin of heterogeneity, a series of random-effects models were fitted excluding two studies [ 64 , 68 ] that were identified as statistical outliers. The exclusion of the studies did not improve heterogeneity which remained high (100%). Therefore, the data were found to be inappropriate for meta-analysis. Heterogeneity is either caused by clinical (sample) or methodological variability [ 36 , 82 ] and is further discussed in the narrative analysis section.

Sample treatment/particle extraction.

The experimental protocol for the extraction of particles differed between the six studies in terms of sample collection, treatment and filtering. Mintenig et al. [ 62 ] filtered the water directly at the sampling sites using stainless steel filter cartridges (3 μm) and then further treated the residue on the filters at the lab. A solution of hydrochloric acid was used to dissolve inorganic material, such as calcium carbonate and iron precipitates, followed by a second filtering through another 3 μm stainless steel filter. The residue was treated again using hydrogen peroxide before the third and final filtration on 0.2 μm aluminium oxide filters. An additional density separation step was used for the raw water samples, employing a zinc chloride solution to remove further iron oxide particles. Strand et al. [ 67 ] also filtered the samples at the sampling sites but using a stainless-steel filter with absolute filtering ability of 11–12 μm. The sample was then treated using a solution of acetic acid. For the collection of the particles used for the spectral analysis, a backwashing procedure with detergent solution was used, this was pre-filtered water and then ethanol under vacuum suction on an Anodisc filter (0.2 μm). Four studies [ 64 , 66 , 68 , 70 ] collected the samples in bottles and then transported them to the lab for processing. Pivokonsky et al. [ 64 ] used wet peroxide oxidation and heat treatment at 75°C for digestion, followed by a double filtration through 5 μm and then 0.2 μm membrane filters (PTFE). Tong et al. [ 68 ] used hydrochloric acid for digestion followed by filtering through 0.2 μm aluminium oxide filters. In contrast, Shruti et al. [ 66 ] and Zhang et al. [ 70 ] did not treat the samples prior to filtering, using 0.22 μm and 0.45 μm pore size filters respectively.

The difference in the pore size of the filters used in the different stages reflects the sizes of the particles extracted which were subsequently further analysed for composition identification, and has thus directly affected the measured MP content. On the other hand, the use of a digestion step to dissolve particulate matter is employed only by some of the studies to extract water impurities and optimize the filtration process.

Spectral analysis.

Differences in the methodology of the studies were identified while important information such as the number of extracted particles and the number of particles that were analysed for composition were not reported ( Table 2 ). Three studies used FTIR for spectral analysis, while Pivokonsky et al. [ 64 ] also used RM for the smaller size range of 1–10 μm. One study used m-FTIR, one RM and one m-RM. A key difference between them is the technical limitation of the instrument regarding the minimum particle size detected. FTIR and RM technical specifications are in the range of 40 μm and 10 μm, respectively. When these methods are used in conjunction with microscopes, it becomes possible to analyse particles down to the size of 10 μm (m-FTIR) and 1 μm (m-RM) [ 31 , 83 – 86 ]. Mintenig et al. [ 62 ] and Zhang et al. [ 70 ] analysed 100% of the filters’ surface, Pivokonsky et al. [ 64 ] about 25% of the sample and Strand et al. [ 67 ] 10% of the filter but coming from only three out of the 17 sampling sites/samples. Shruti et al. [ 66 ] and Tong et al. [ 68 ] did not report the amount of the sample analysed.

https://doi.org/10.1371/journal.pone.0236838.t002

None of the studies reported the final number of particles analysed and only Strand et al. [ 67 ] reported the success rate of conclusive identification (44%) and the proportion that was identified as MPs (3%). Only the two studies by Pivokonsky et al. [ 64 ] and Zhang et al. [ 70 ] reported the similarity index for the spectral analysis, 80% and 70%, respectively. Although scientific guidance on the particles that need to be analysed does not exist, it is reasonable to assume that larger proportions would lead to more robust results. Mintenig et al. [ 62 ] did not analyse the fibres at all. Although a larger number of fibres were discovered compared with ‘particles’ in the samples, spectral analysis was not utilised because the fibre presence was attributed to their presence as post-sampling contamination. Fibres are a high proportion of MPs and their complete exclusion from the results might have resulted in an underestimation of MP content.

Particle size.

The key difference in the studies’ protocol is the size of the particles identified and verified via spectral analysis and is directly connected to the extraction process and the composition identification process used. Shruti et al. [ 66 ] only analysed particles >500 μm, Mintenig et al. [ 62 ] ≥20 μm, Strand et al. [ 67 ] and Zhang et al. [ 70 ] ≥10 μm, Pivokonsky et al. [ 64 ] ≥1 μm, while Tong et al. [ 68 ] did not report the minimum size. The study by Pivokonsky et al. [ 64 ] reported the highest MP content ranging from 338 ±76 to 628 ±28 MPs/L and stated that 25–60% of the MPs were in the range of 1–5 μm and 30–50% in the range of 5–10 μm. Tong et al. [ 68 ] reported content in the same magnitude of 440 ±275 MPs/L, and state that MPs <50 μm were significantly dominant. It must be noted that Tong et al. [ 68 ] used only Nile Red dying and visual identification for the determination of particle size in a reported range of 3–4453 μm. The results from these two studies present a noteworthy difference. When the MPs’ size range is taken into consideration it becomes clear that this variance could be attributed to the fact that the other four studies were not able to detect that same range of sizes ( Fig 4 ). In addition, it should be noted that although Strand et al. [ 67 ] state that particles were measured down to 10 μm, the majority of the results were based on particles ≥100 μm. The inverse relationship between the size of MPs and their abundance is further supported by the findings of Shruti et al. [ 66 ] who reported that 75% of the particles were in the range of 100 μm– 1 mm, Zhang et al. [ 70 ] who reported that 46% were in the range of 500 μm -1 mm and Mintenig et al. [ 62 ] who found that all particles were in the range of 50–150 μm.

MP content (MPs/L) is illustrated in the left-hand side y axis in log 10 scale. BW: diagonal stripes, TW: chequerboard, Minimum particle size included in each study is illustrated in the right-hand side y axis. Studies by Tong et al. [ 68 ], Wiesheu et al. [ 69 ] and Zuccarello et al. [ 71 ] were not included because they were rated as of high RoB.

https://doi.org/10.1371/journal.pone.0236838.g004

Bottled water

Six studies samples BW ( Table 3 ). Kankanige and Babel [ 60 ] sampled spring and TW, Mason et al. [ 61 ] sampled table and mineral water and the rest of the studies sampled only mineral water. Three different container materials were selected: plastic (single-use and reusable), glass and carton. MPs content ranged from 0 to 1.1 X 10 8 MPs/L across all containers. The percentage of samples containing MPs ranged from 92% to 100%. Fragments and films were the most commonly identified shape.

https://doi.org/10.1371/journal.pone.0236838.t003

Meta-analysis was attempted using the results from four of the studies [ 51 , 60 , 65 , 71 ] which provided the necessary data. Statistical heterogeneity as measured by Higgins I 2 test [ 72 ] in a random-effects model was found to be high, I 2 = 99%, even when the high RoB study by Zuccarello et al. [ 71 ] was excluded ( S2 and S3 Figs). Examining the four different types of containers separately in a mixed-effects subgroup analysis [ 80 , 81 ], statistical heterogeneity within the groups still remained high I 2 <84% ( S4 Fig ). The pooled effect estimate was accompanied by a 95% confidence interval which included negative values for all categories, further showing that meta-analysis was not appropriate. The results of the analysis showed that pooling of the data was not appropriate. The origin of heterogeneity is addressed in the narrative analysis.

Four studies [ 60 , 61 , 65 , 69 ] did not use a digestion process. Mason et al. [ 61 ] used glass-fibre filters (1.5 μm pore size), Schymanski et al. [ 65 ] used gold-coated poly-carbonate filters (3.0 μm pore size) while both studies by Kankanige and Babel [ 60 ] and Wiesheu et al. [ 69 ] used cellulose nitrate filters (0.45 μm pore size). Oßmann et al. [ 63 ] implemented a digestion process using an ethylene diamine tetra-acetic acid tetrasodium salt (EDTA) solution then followed by a density separation (flotation) step via a detergent solution of sodium dodecyl sulphate (SDS) and filtration through aluminium-coated polycarbonate membrane filters (0.4 μm pore size). Zuccarello et al. [ 71 ] did not employ a digestion nor a filtration process, opting for a newly developed method to target MPs <10 μm, which differs significantly from previous studies and cannot thus be directly compared to the rest of the studies. The alternative approach used nitric acid and a high temperature incubation (60° C for 24 hours) for mineralization of the samples to remove carbon-based particles. This was followed by vortexing, centrifugation, addition of dichloromethane, resuspension using acetonitrile and drying. The sample was then deposited on an aluminium and copper alloy stub to be coated with gold before SEM-EDX analysis [ 87 ]. The methods used by this study have already been highlighted [ 88 ] under the reporting and verification sections of the analytical methods which was partially addressed by a corrigendum of the authors [ 87 ]. The scientific base of the process employed is a publication that is not available in English [ 89 ] and therefore cannot be assessed, as well as a second publication [ 90 ] concerning MPs extraction method from the gastrointestinal tract of fish. The latter describes a different method (two-step digestion process using sodium hydroxide and nitric acid, followed by filtration, density separation and verification by visual identification alone, that subsequently targets MPs of a completely different size of >100 μm).

Schymanski et al. [ 65 ] examined the largest number of particles in RM spectral analysis, analysing 100% of the particles or a maximum of 1000 (in the 5–10 μm size fraction) on each of the filters, corresponding to each of the 38 samples ( Table 3 ). The verified MP particles ranged from 0.03 to 10.7% of the analysed particles, using a ≥ 70% spectral similarity index. Kankanige and Babel [ 60 ] analysed 100% of the extracted particles (>50 μm), using FTIR and a 60% spectral similarity index, verifying 45.8% of them as MPs. RM analysis was used for particles of the lower range of 1–10 μm but these findings are not reported in the details of the analysis. Mason et al. [ 61 ] also used FTIR but only for particles ≥100 μm and examined around 1000 particles which was almost 50% of the particles extracted, using a ≥ 70% similarity index verifying 40% of the particles as MPs. Oßmann et al. [ 63 ] on the other hand, did not provide information on the number of extracted particles, reporting the analysis of 4.4% of the surface of each filter using RM, but not reporting how many were finally verified as MPs. Oßmann et al. [ 63 ] did not use an automated software option in which spectral similarity is calculated automatically but a mix of semi-automated methods. In this sense, a standardized spectral similarity index was not utilised, which might have introduced experimental error into this protocol. Wiesheu et al. [ 69 ] only analysed the one fibre extracted from the samples isolated, not providing further details on the methods employed.

Zuccarello et al. [ 71 , 87 ] used SEM-EDX for the identification of MPs. No digestion or filtration process for the extraction of the mineral water impurities was employed. The authors suggest that the mineralization process extracts all carbon-containing particles that are not plastic. This removal needs to be done with near unit efficiency due to the fact that typical concentrations of carbonates in mineral water exceed, by many orders of magnitude, the reported MP concentrations in BW samples in other studies. The specificity of this method has not been proven as mentioned in the previous section. The aim of the method was to quantify the number of MPs per volume in the size range of 0.5–10 μm and a further objective was to calculate the mass of MPs per volume, using the density of the plastic bottles containing the water. The reported validation of the process used is weak in that the mass of MPs per volume was measured in three samples spiked with MPs (whose size was not reported), and then a calculation of MPs per volume was conducted, which is the opposite way round to the calculation made with the unknown samples and may introduce systematic error.

Mason et al. [ 61 ] used FTIR only for particles ≥100 μm but reported that 95% of particles were between 6.5 and 100 μm. The MP content for all sizes was 325 MPs/L, whereas for particles ≥100 μm it was only 10.4 MPs/L. In addition, it was not clear what maximum size cut-off was employed. Kankanige and Babel [ 60 ] used FTIR for particles ≥50 μm but extrapolated the findings to the smaller size range 6.5–50 μm, reporting MPs contents of 140 ±19 MPs/L for plastic bottles and 52 ±4 MPs/L for glass bottles. The size range of 6.5–20 μm was identified as the most dominant. Schymanski et al. [ 65 ] extracted and analysed particles including even smaller sizes of ≥5 μm and reported that 80% of the verified MPs were in the range of 5 and 20 μm, with MP contents of 14 ±14 MPs/L for single use plastic bottles, 118 ± 88 MPs/L for reusable plastic bottles, 11 ± 8 MPs/L for carton and 50 ± 52 MPs/L for glass bottles. Oßmann et al. [ 63 ] decreased the size of the included particles to ≥1 μm reporting much higher MP contents of 2649 ± 2857 MPs/L for single use PET bottles, 4889 ± 5432 MPs/L for reusable PET bottles and 6292 ± 10521 MPs/L for glass bottles. The same authors also highlight that more than 95% of MPs were smaller than 5 μm and 50% smaller than 1.5 μm. Zuccarello et al. [ 71 ] focused on the 0.5–10 μm size range, reporting high concentrations of 5.42 ± 1.95 X 10 7 MPs/L. Although the size range of the identified MPs (1.28–4.2 μm) is similar to the Oßmann et al. [ 63 ] study (>1 μm), the results differ by a factor of 11000, further highlighting the possible quality issues of the study. The results of the Wiesheu et al. [ 69 ] study on MPs content were inconclusive. As can be seen in Fig 4 , as the size of the identified particles decreases, the MP content increases significantly.

Twelve studies were systematically reviewed, which collectively analysed more than 40000 L of TW and 435 bottles of BW (table and mineral water). It would not be reasonable to collate the evidence from the twelve studies included in this systematic review due to key differences that were identified in the experimental protocols and high sample heterogeneity. In addition, the lack of key information (e.g. SE, SD) and high statistical heterogeneity hinder the execution of meta-analysis in an attempt to quantify MP content. RoB was found to be low in the majority the studies. Two studies were rated as of high RoB and therefore the results of these are excluded. The study by Zuccarello et al. [ 71 ] was rated high RoB in the two domains of sampling and reporting, while the study by Wiesheu et al. [ 69 ] was rated high RoB in the domains of analysis and reporting.

All studies reported some level of MP contamination. Samples positive for contamination ranged from 24–100% in TW and 92–100% for BW. Comparing the results between the different water origins, specifically between the two studies [ 63 , 64 ] that targeted similar MP sizes of minimum 1 μm, MP content was higher in BW (plastic and glass bottles) than TW ( Fig 4 ). Therefore, current evidence suggests that there are higher rates of MP contamination in BW compared with TW, both in terms of frequency and quantity. Regarding the primary origin of BW, Mason et al. [ 61 ] analysed table and mineral BW and Kankanige and Babel [ 60 ] tap and spring BW, but did not report a comparison between the different water origins which could shed some light on the possible differences.

The methodology used in the studies varied in both sampling and analysis. Standardization of the experimental protocols is key in order to increase confidence in the quality of the studies and certainty of the evidence. The first step in obtaining comparable and trustworthy results is the use of a verified composition identification process, which was employed by all of the studies included in this review. Not using such a process has been proven to lead to gross under- or over-estimations [ 31 , 91 , 92 ]. Even with all the studies using either FTIR, RM or SEM-EDX, there were still differences in the spectral similarity index, the number and proportion of the particles analysed, and the spectral library used. Furthermore, poor reporting hindered the assessment of the experimental protocols’ effectiveness; only one study [ 60 ] reported how many particles were retrieved from the extraction process and only four [ 60 , 61 , 65 , 69 ] reported how many particles were analysed for composition identification.

The most significant difference in the methods is the size of the particles that were extracted from the samples and analysed for composition identification. Studies using FTIR and RM were able to analyse particles down to 1 μm which significantly influenced the results. The degradation of MPs in the marine environment and the exponential increase of the number as the size decreases has been experimentally and mathematically explored [ 93 – 95 ]. This would suggest that the same fragmentation pattern may also apply to other aquatic environments as well.

On the other hand, only seven [ 62 – 64 , 66 , 68 – 71 ] of the twelve studies reported the upper limit of the range in MP size. The importance of defining and reporting the size range of the identified MPs has a double significance as follows. As a methodology parameter it is connected to the quantified MP content results. As a food contamination parameter, it is indicative of the potential health effects. MPs <1.5 μm are characterized as more dangerous since they are, in theory, capable of crossing the gut epithelium, further progressing into the human body and thus possibly causing an adverse health effect [ 23 ].

Differences in sample size were striking, ranging from 36 to 32000 L (per study) for TW and 3 to (>)130 L for BW. At the moment, methodological consensus concerning sample size does not exist. Koelmans et al. [ 30 ], in a recent review, proposed a minimum of 1000 L for TW and 500 L for BW. In the first instance, sample size is dictated by the objectives and design of the study which in many cases are a function of the available resources [ 96 , 97 ]. Sample size should be directly connected to the contaminant under examination. The volume of the samples as well as the sampling frequency can only be set when there is enough evidence to support what a meaningful MP content is. Meaningful being expressed in terms of food safety linked to human health and what is considered to be ‘wholesome and clean’ water intended for human consumption, which is the requirement of relevant European regulations and universal standards [ 43 , 49 , 98 ]. At the moment, there is not enough evidence to formulate an informed guideline for sampling sizes, nevertheless scientific experience points to larger sample sizes being more robust and reliable [ 99 ].

Another area of importance is quality assurance of sampling and sample handling to avoid cross contamination via airborne MPs. This issue was addressed by our RoB assessment tool in the sampling domain. In addition, only studies that employed blank procedural samples to account for this type of experimental error were included [ 100 , 101 ]. The lack of detailed information on the results and the significance of procedural blank samples downgraded the quality of the study as assessed by the RoB assessment tool. The bespoke RoB tool used did not employ scales to rank the studies as done by other reviews in the field [ 30 ] but is a domain-based evaluation according to the guidance of leading methodology regarding systematic reviews [ 36 ]. The use of scales in RoB assessment is explicitly discouraged as research experience has shown that they can be unreliable [ 57 ].

Seven studies used samples from Europe (3 TW, 4 BW), three from Asia (2 TW, 1 BW), one from North America (TW), and one from multiple continents (BW) ( S3 Table ). The highest MPs content are reported in Europe for both TW and BW. Regarding TW, the highest reported MPs content for Europe and Asia were in the same magnitude but almost 25 times higher than those reported for the samples from North America. In BW, the maximum reported MPs content in Europe was 35 times higher than that reported in Asia. However, it is not clear if this is due to the number of existing studies and the varying methodology employed, or the geographical location. Recent research has shown that MP contamination of the environment is directly linked to waste management, which is compromised in developing countries [ 102 , 103 ]. In this sense, it would be reasonable to expect higher MPs contamination of potable water in these countries, where further research is needed. In terms of polymeric composition, PET and PP were the most prevalent polymers identified in BW. The differences between the polymeric composition in the various BW studies can be attributed to the different origin of the water, processing, the material used for packaging but also to the different particle sizes the studies extracted and analysed since degradation rates between polymers vary [ 2 , 104 ]. In TW, polymeric composition varied with PET and PP present along with polyester, PTT and rayon. This may possibly due to the wide geographical and environmental origin of the water samples. Rayon is a man-made but not synthetic fibre and is not included in most MP research. It should be noted that the most produced and used polymers for the last 15 years have been PE and PP, whose prevalence would be anticipated to be the highest in terms of environmental contamination although geographical variation is expected [ 17 – 20 ]. Fragments and fibres were the prevalent MP shape in both categories, highlighting an agreement in the findings across all studies. Polymeric composition and shape characteristics can be used as guides to the origin of MPs as well as to focus future toxicological research.

A recent review by Koelmans et al. [ 30 ] has recently addressed the issue of MPs contamination of drinking water. Koelmans et al. [ 30 ] focused not only on drinking water but also on freshwater MP contamination and experimental methodology and did not attempt quantitative collation of the evidence. The study assessed the quality of the studies using a bespoke rating system, focusing on different aspects of experimental design and execution using a scoring system. The use of scoring scales in quality assessment is explicitly discouraged by the Cochrane Collaboration, which is the leading body of systematic reviews, as research experience has shown that they can be unreliable due to the lack of justification for the ratings [ 36 , 51 , 57 , 105 ]. The World Health Organization (WHO) delivered a report [ 24 ] based on a commissioned systematic review by Koelmans et al. [ 30 ], yet the authors make no claim that it is systematic, nor is there a description of the relevant review methods utilised, such as the existence of a published protocol.

Human MPs exposure via drinking water

Water intake varies in adults depending on gender, climate, diet and physical activity. The WHO guideline value for water daily consumption is 2 L for adults (with a default body weight of 60 kg), 1 L for children (default body weight of 10 kg) and 0.75 L for infants (default body weight of 5 kg) [ 98 ]. Maximum daily human exposures were calculated by using the highest MP content evidence that have been rated of low and unclear RoB for the three continents, and the WHO values for daily water consumption and use [ 98 ]. The highest daily possible exposures were calculated in Europe at 1260 MPs for TW and 9800 MPs for BW ( Table 4 ). These exposures are significant underestimations since they assume that all populations have access to treated drinking water which is not the case. These high exposure levels are driven more by the amount of water we consume and less the absolute MP content of water compared to other food categories.

https://doi.org/10.1371/journal.pone.0236838.t004

After the ingestion of MPs, particles <1.5 μm could pass the gut barrier and translocate to other organs. Paradigms from studies on plastic material that have been used for orthopaedic replacement prosthetics have proved translocation of plastic particles to organs such as the liver, spleen and lymph nodes [ 106 – 109 ]. The effects of MPs will depend on their size, polymeric composition, additives (plasticisers), the chemicals that they might have absorbed from the environment, their chemical state and where they are located in the human body [ 41 , 110 ].

An additional possible exposure pathway that has not yet been investigated may occur from the use of MP contaminated water for incorporation into food. According to WHO estimations, 7.5 L of water per capita per day [ 98 ] is used by most people in most situations around the world for hydration and incorporation into food. This is a complex issue since it is not clear to what extent MPs in the water would be taken up into the foodstuffs. This would depend on how the food is prepared and have geographic, cultural variation. Nevertheless, further research into this issue is clearly warranted as it is another potential pathway for MPs in water to enter the human body.

Strengths and limitations

To our knowledge this is the first systematic review focusing on MP contamination of water intended for human consumption. The review was based on a protocol which was created beforehand, outlining the methodology used throughout. The protocol ensures that bias is not introduced. In addition, the quality of studies was assessed using a systematic RoB tool tailored to the needs of the review, addressing every stage of design, execution and reporting of research. The review was limited to a narrative analysis and did not include a meta-analysis due to high sample, experimental and statistical heterogeneity as well as poor reporting in a fraction of the studies. The majority of the studies were assessed to be low RoB.

Research methodology in the field of MPs environmental contamination has advanced in recent years, especially with the use of FTIR and RM validation of particle characteristics, but is still lacking in quality and robustness. The systematic review identified specific areas where further development and standardization is needed:

• Sampling methodology: sampling size, location, frequency, instruments, quality assurance, procedural blanks, replicate samples.
• Registry of all relevant sample characteristics when available: brand, geographical and environmental origin, volumes, production dates, information on water treatment and additives.
• Particle extraction process specifications: sample volumes, chemicals used for digestion and density separation, type and pore size of filters.
• ○. Use of one of the currently validated methods: FTIR, RM, SEM, Pyr-GC-MS and SEM/EDS.
• ○. Proportion of extracted particles for analysis.
• ○. Spectral similarity index and which spectral libraries are used (bespoke or commercially available).
• Post-sampling handling: measures to protect cross-contamination and use of procedural blank samples in all experimental aspects to ensure effectiveness and account for experimental errors.
• Detailed reporting of all aspects of research including design, execution and statistical analysis.

In terms of future research there is a clear need for research on MP contamination of drinking water in countries beyond Europe where there is less data. Comparison between table water, natural mineral and spring waters to detect differences is another area that has not been explored. The additional exposure pathway via the use of MP contaminated water for incorporation into food also merits further research.

As this review shows, there are still relatively few studies examining MP contamination in drinking water, and levels vary significantly. The presence of MP in human stool samples has recently been verified [ 28 ], although the effects on human health are still under examination [ 28 , 41 , 111 – 113 ]. Given the amount of water humans drink and its use for incorporation into food, a clearer understanding of the levels of MP present in drinking water is needed, in order to better assess the risks that MPs in water present. Quantification of MPs human exposures is an integral part of the exposure assessment in the wider frame of a risk assessment to determine the likelihood of MPs having adverse human health effects [ 114 , 115 ].

Our findings support the omnipresent MPs contamination of drinking water. Current food and drinking water safety regulation and standards around the world [ 49 , 116 , 117 ] adopt the precautionary principle [ 118 , 119 ] on food safety risk management. The principle dictates that in the face of scientific uncertainty concerning possible harmful effects, after an initial assessment of available evidence has been completed and a comprehensive risk assessment is anticipated, risk management measures must be adopted in order to ensure the protection of health. The weight of the current evidence suggests that the time may have come to implement protective measures against the ingestion of MPs.

Supporting information

S1 checklist. prisma checklist..

https://doi.org/10.1371/journal.pone.0236838.s001

S1 Protocol. Systematic review protocol.

Published in the International prospective register of systematic reviews (PROSPERO)

https://doi.org/10.1371/journal.pone.0236838.s002

S1 Appendix. Exclusion reasons during the second level screening.

https://doi.org/10.1371/journal.pone.0236838.s003

S1 Table. Search strategy for MEDLINE (OVID).

https://doi.org/10.1371/journal.pone.0236838.s004

S2 Table. Risk of bias (RoB) assessment tool template.

https://doi.org/10.1371/journal.pone.0236838.s005

S3 Table. Study characteristics.

https://doi.org/10.1371/journal.pone.0236838.s006

S1 Fig. Forest plot of TW studies random-effects model analysis.

The x axis represents the standardized mean difference (SMD) expressed in MPs/L. The vertical line is the line of null effect where MP content is 0. The grey boxes represent the pooled effect estimate and the lines the CI 95%. The size of the boxes is proportional to the study weight. The diamond is the combined point estimate and CI for each of the subgroups.

https://doi.org/10.1371/journal.pone.0236838.s007

S2 Fig. Forest plot of BW studies random-effects model analysis.

The x axis represents the standardized mean difference (SMD) expressed in MPs/L. The vertical line is the line of null effect where MP content is 0. The grey boxes represent the pooled effect estimate and the lines the CI 95%. The size of the boxes is proportional to the study weight.

https://doi.org/10.1371/journal.pone.0236838.s008

S3 Fig. Forest plot of BW studies random-effects model analysis excluding the high RoB study.

https://doi.org/10.1371/journal.pone.0236838.s009

S4 Fig. Forest plot of sub-group analysis of BW studies.

Mixed-effects (plural model) analysis. The x axis represents the standardized mean difference (SMD) expressed in MPs/ L. The vertical line is the line of null effect where MP content is 0. The grey boxes represent the pooled effect estimate and the lines the CI 95%. The size of the boxes is proportional to the study weight. The diamonds are the combined point estimates and CI for each of the subgroups. The red square is the overall pooled effect for all subgroups.

https://doi.org/10.1371/journal.pone.0236838.s010

• View Article
• PubMed/NCBI
• Google Scholar
• 17. Plastics Europe. The Compelling Facts About Plastics. An analysis of plastics production, demand and recovery for 2006 in Europe. Plastics Europe, 2008.
• 18. Plastics Europe. Plastics: the Facts 2017: An analysis of European plastics production, demand and waste data. 2017.
• 19. Plastics Europe. Plastics–the Facts 2018; An analysis of European plastics production, demand and waste data. 2018.
• 20. Plastics Europe. Plastics–the Facts 2019; An analysis of European plastics production, demand and waste data. Plastics Europe, 2019.
• 24. WHO. Microplastics in drinking-water. Geneva: World Health Organization, 2019 Report No.: 9241516194.
• 27. EFSA. Definition and description of “emerging risks” within the EFSA's mandate. (adopted by the Scientific Committee on 10 July 2007). Parma: European Food Safety Authority, 2007.
• 36. Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, et al. Cochrane Handbook for Systematic Reviews of Interventions. Version 6.0 (updated July 2019). Cochrane.: Cochrane; 2019. Available from: www.training.cochrane.org/handbook .
• 37. FAO, WHO. Principles and methods for the risk assessment of chemicals in food: Environmental Health Criteria 240. Stuttgart, Germany: Food and Agriculture Organization of the United Nations and the World Health Organization, 2009.
• 38. IPCS. World Health Organization human health risk assessment toolkit: chemical hazards. Geneva: World Health Organization, 2010.
• 39. WHO. International Programme on Chemical Safety (IPCS): Principles for the assessment of risks to human health from exposure to chemicals. Geneva: World Health Organization: 1999.
• 43. Council directive 98/83/EC. On the quality of water intended for human consumption. European Council. 1998.
• 44. Directive 2009/54/EC. On the exploitation and marketing of natural mineral waters. European parliament and European Council. 2009.
• 45. The Natural Mineral Water Spring Water and Bottled Drinking Water (England) (Amendment) Regulations. United Kingdom. 2018;SI 2018:352.
• 48. Centre for Evidence-Based Medicine [Internet]. Study Designs 2019 [16–10–2019]. Available from: https://www.cebm.net/2014/04/study-designs/ .
• 49. Regulation (EC) No 178. Laying down the general principles and requirements of food law, establishing the European Food Safety Authority and laying down procedures in matters of food safety. European Parliament and Council. 2002.
• 52. Centre for Reviews and Dissemination (CRD). Systematic reviews: CRD's guidance for undertaking reviews in health care. York, United Kingdom: Centre for Reviews and Dissemination, University of York; 2009.
• 54. West S, King V, Carey T, Lohr K, McKoy N, Sutton S, et al. Systems to rate the strength of scientific evidence: summary. Rockville, MD, USA: Agency for Healthcare Research and Quality (US), 2002.
• 57. Higgins JPT, Green SP, Cochrane C. Cochrane handbook for systematic reviews of interventions. Chichester, United KIngdom: John Wiley & Sons; 2011.
• 67. Strand J, Feld L, Murphy F, Mackevica A, Hartmann NB. Analysis of microplastic particles in Danish drinking water. DCE-Danish Centre for Environment and Energy, 2018 877156358X.
• 73. R Core Team. R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing; 2019.
• 74. RStudio Team. RStudio: Integrated Development for R. RStudio. Boston, MA: Inc.; 2018.
• 77. Harrer M, Cuijpers P, Furukawa T, Ebert D-D. dmetar: Companion R Package For The Guide 'Doing Meta-Analysis in R'. 2019.
• 78. McGuinness L, Kothe E. robvis: Visualize the Results of Risk-of-Bias (ROB) Assessments. 2019.
• 79. Hadley W. ggplot2: Elegant Graphics for Data Analysis. New York: Springer-Verlag.; 2016.
• 80. Chen DG, Peace KE. Applied meta-analysis with R. Peace KEa, editor. Boca Raton, Florida, USA: CRC Press; 2013.
• 84. Bergmann M. Marine Anthropogenic Litter. Gutow L, Klages M, editors. Cham: Springer; 2015.
• 96. EPA. Guidance for Data Quality Assessment. Practical Methods for Data Analysis. United States Environmental Protection Agency, 2000 Contract No.: EPA/600/R-96/084.
• 97. EPA. Guidance on choosing a sampling design for environmental data collection, for Use in Developing a Quality Assurance Project Plan. United States Environmental Protection Agency, 2002 Contract No.: EPA QA/G-5S.
• 98. WHO. Guidelines for drinking-water quality, fourth edition incorporating the first addendum. Geneva: World Health Organization, 2017.
• 99. Zhang C. Fundamentals of environmental sampling and analysis. Hoboken, N.J., USA: Wiley; 2007.
• 105. Whiting P, Savović J, Higgins JPT, Caldwell DM, Reeves BC, Shea B, et al. ROBIS: Tool to assess risk of bias in systematic reviews; Guidance on how to use ROBIS2016 01-03-2019. Available from: https://vle.york.ac.uk/bbcswebdav/pid-2989084-dt-content-rid-6036201_2/courses/Y2016-002677/robisguidancedocument.pdf .
• 109. GESAMP. Sources, fate and effects of microplastics in the marine environment: a global assessment. London, UK: The Joint Group of Experts on Scientific Aspects of Marine Environmental Protection, Working Group 40, 2015.
• 110. GESAMP. Sources, fate and effects of microplastics in the marine environment: part two of a global assessment. London, UK: The Joint Group of Experts on Scientific Aspects of Marine Environmental Protection, Working Group 40, 2016.
• 114. SAM. Environmental and Health Risks of Microplastic Pollution; Scientific Advice Mechanism. Group of Chief Scientific Advisors. Luxembourg: European Commission, 2019.
• 115. SAPEA. A Scientific Perspective on Microplastics in Nature and Society. Berlin: Science Advice for Policy by European Academies, 2019.
• 116. ISO. ISO 22000:2018. Food safety management systems—Requirements for any organization in the food chain. 2018 [13–3–2020]. Available from: https://www.iso.org/standard/65464.html .
• 117. Wallace C. HACCP a food industry briefing. Second edition. ed. Chichester, West Sussex, United Kingdom: Wiley-Blackwell; 2015.
• 119. Jackson W, Steingraber S. Protecting public health and the environment: implementing the precautionary principle. Washington DC, USA: Island Press; 1999.

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• 2025-present Environmental Research: Water Online ISSN: 3033-4942

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• Published: 16 September 2024

Prevalence and epidemiological distribution of indicators of pathogenic bacteria in households drinking water in Ethiopia: a systematic review and meta-analysis

• Ermias Alemayehu Adugna 1 ,
• Abel Weldetinsae 1 ,
• Zinabu Assefa Alemu 1 ,
• Alemneh Kabeta Daba 1 ,
• Daniel Abera Dinssa 1 ,
• Tiruneh Tariku 2 ,
• Mesaye Getachew Weldegebriel 1 ,
• Melaku Gizaw Serte 1 ,
• Kirubel Tesfaye Teklu 1 ,
• Moa Abate Kenea 1 ,
• Gebretsadik Keleb Yehuala 3 ,
• Masresha Tessema 1 &
• Aderajew Mekonnen Girmay 1  

BMC Public Health volume  24 , Article number:  2511 ( 2024 ) Cite this article

Metrics details

Ensuring the availability of safe drinking water remains a critical challenge in developing countries, including Ethiopia. Therefore, this paper aimed to investigate the prevalence of fecal coliform and E. coli bacteria and, geographical, children availability, and seasonal exposure assessment through a meta-analysis.

Two independent review groups extensively searched internet databases for English-language research articles published between 2013 and 2023. This systematic review and meta-analysis followed PRISMA guidelines. The methodological quality of each included study was evaluated using the STROBE guidelines. Publication bias was assessed by visual inspection of a funnel plot and then tested by the Egger regression test, and meta-analysis was performed using DerSimonian and Laird random-effects models with inverse variance weighting. Subgroup analyses were also conducted to explore heterogeneity.

Out of 48 potentially relevant studies, only 21 fulfilled the inclusion criteria and were considered for meta-analysis. The pooled prevalence of fecal coliform and E. coli was 64% (95% CI: 56.0–71.0%, I 2  = 95.8%) and 54% (95% CI: 45.7–62.3%, I 2  = 94.2%), respectively. Subgroup analysis revealed that the prevalence of fecal coliform bacteria increased during the wet season (70%) compared to the dry season (60%), particularly in households with under-five children (74%) compared to all households (61%), in rural (68%) versus urban (66%) areas, and in regions with high prevalence such as Amhara (71%), Gambela (71%), and Oromia (70%). Similarly, the prevalence of E. coli was higher in households with under-five children (66%) than in all households (46%).

Conclusions

The analysis highlights the higher prevalence of fecal coliform and E. coli within households drinking water, indicating that these bacteria are a significant public health concern. Moreover, these findings emphasize the critical need for targeted interventions aimed at improving drinking water quality to reduce the risk of fecal contamination and enhance public health outcomes for susceptible groups, including households with under-five children, in particular geographical areas such as the Amhara, Gambela, and Oromia regions, as well as rural areas, at point-of-use, and during the rainy season.

Registration

This review was registered on PROSPERO (registration ID - CRD42023448812).

Peer Review reports

Introduction

An essential requirement for the health and well-being of people is access to safe drinking water. However, most of the world’s population lacks access to adequate, sustainable, and safe water [ 1 , 2 ]. Considering this, in 2015, the United Nations ratified different developmental goals, including the Sustainable Development Goal (SDG) 6.1, which aspires to achieve universal and equitable access to safe and affordable drinking water for all by 2030 [ 3 ]. This goal emphasizes having access to safe drinking water for every household [ 4 ]. To monitor this phenomenon, most countries, including Ethiopia, have adopted the World Health Organization’s (WHO) guidelines for drinking water quality [ 1 ].

Worldwide, water-related diseases account for approximately 80% of all illnesses and diseases and, in turn, cause an estimated 505,000 diarrheal deaths each year [ 5 ]. Children are more susceptible to microbiological pollutants and develop an illness due to their immature immune systems [ 6 ]. As a result, waterborne diseases continue to be major health problems worldwide. Particularly in most developing nations where access to potable water is scarce, water-borne diseases are a serious public health concern as a result of bacterial contamination of drinking water [ 7 ]. Water-borne pathogenic bacteria could infect or harm humans by secreting toxins that could harm human tissue, living as parasites within human cells, or colonizing within the body to interfere with regular bodily processes. Numerous harmful bacteria, such as fecal coliforms, Escherichia coli , Salmonella typhi , and Vibrio cholerae , have been identified in water [ 8 ]. These bacteria can lead to various waterborne diseases, including cholera, typhoid, and diarrhea [ 5 ].

In developing countries, the main causes of diarrheal diseases are bacteria, protozoa, viruses, and helminths [ 9 ]. Specifically, in rural areas of most developing countries, where water sources are communally shared and exposed to several fecal-oral transmission channels within their local boundaries, fecal contamination of drinking water is a primary cause of water-borne diseases, including fatal diarrhea [ 10 ]. This could be detected by examining the presence of potential indicator organisms such as fecal coliforms [ 11 , 12 ].

Several pathogenic bacteria can be transmitted via polluted drinking water [ 13 , 14 ]. Drinking water can be polluted at the source, distribution line, and/or household level, and such polluted water can be a vehicle for several pathogens [ 2 , 15 ]. In Ethiopia, poor environmental health conditions resulting from subpar water quality and inadequate hygiene and sanitation standards are responsible for more than 60% of infectious diseases [ 16 ]. Studies conducted in Ethiopia revealed that the prevalence of fecal contamination in drinking water, including Escherichia coli ( E. coli ), total coliforms (TC), and fecal coliforms, have been extremely high [ 17 , 18 , 19 , 20 , 21 , 22 ].

This could be due to many reasons, as water safety depends on various factors, from the quality of the source water to its storage and handling practices in the home [ 23 ]. Even if the source is clean, the process of collecting, transporting, storing, and drawing water in the household can all lead to fecal contamination [ 17 ]. In addition, pollutants in drinking water sources include human excreta, animal waste, effluent agricultural practices, and floods, as well as a lack of knowledge among end-users about hygiene and environmental cleanliness [ 17 , 24 ]. Due to inadequate access and frequent interruptions in the piped water supply [ 25 ], drinking water is commonly stored, often for considerable lengths of time, resulting in gross contamination [ 26 ].

Therefore, understanding the extent and epidemiological variation of bacterial contamination in household drinking water is vital for policymakers and public health officials to allocate resources efficiently and target interventions effectively to reduce the burden of waterborne illnesses in Ethiopia. Despite individual studies on contamination levels, there is a notable research gap due to the lack of a national systematic review and meta-analysis. Existing research does not fully examine how contamination varies with factors such as children’s availability, geographic regions, water sources, and seasonal changes. This study aims to address this gap by offering a comprehensive review and meta-analysis, providing essential insights for policymakers to effectively allocate resources and target interventions to reduce waterborne illnesses and support vulnerable groups.

Methodology

Data sources and search strategy.

The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [ S1 ] and the protocol of this study was registered with the International Prospective Register of Systematic Reviews (PROSPERO), with protocol registration number CRD42023448812. With a focus on English-language materials, we conducted an exhaustive search across numerous electronic databases, including PubMed, Web of Science, Google Scholar, ScienceDirect, ProQuest, Directory of Open Access Journals, POPLINE, African Journals Online, and the Cochrane Library. The search strategy included a combination of keywords and controlled vocabulary related to Ethiopia, drinking water, and specific indicators of pathogenic bacteria. Moreover, the search strategies for Google Scholar were [Microbiological OR Microorganisms OR Organisms OR Bacteriological OR pathogens] AND [“Water quality” OR “Water contamination”] AND [household OR domestic OR residential OR home] AND [“Drinking water”] AND [intitle: Ethiopia], and those for Pubmed were ((Microbiological OR Microorganisms OR Organisms OR Bacteriological OR pathogens) AND (“Water quality” OR “Water contamination”)) AND (household OR domestic OR residential OR home)) AND (“Drinking water”)) AND (Ethiopia [Title]). we have provided a detailed breakdown of the query [ S5 ].

Study selection criteria

Studies were included if they met the following criteria: (i) Original research was conducted in Ethiopia, and only peer-reviewed journal articles, as they undergo rigorous review processes and were more likely to meet high-quality standards; (ii) Focus on the prevalence of those specific indicators of pathogenic bacteria in household drinking water; (iii) Published in English; (vi) Articles with a cross-sectional study, had freely available full texts and were published between 2013 and 2023. However, articles with no clear data were excluded.

Methodological quality of the included studies

Two groups independently assessed the methodological rigor of every study included, employing the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines [ 27 ]. Each study was then classified based on its quality: “Good” (G) if it achieved a score of at least 70% of the total points, “Fair” (F) if it scored between 50% and 69%, and “Poor” (P) if its score was below 50% [ S2 ].

Extraction and analysis

Following the selection of pertinent articles, two investigators individually screened the titles and abstracts to determine their suitability for full-text review. Subsequently, these investigators utilized a standardized data extraction template in Microsoft Office Excel 2021 to collect study characteristics, prevalence, sample sizes, season, child availability, water sources, and geographic locations. In the event of any disagreements between the two investigators, a third investigator intervened, and their decision was considered final. The data analysis was performed using STATA 16.0 software. Random effects meta-analysis models were used to investigate the pooled prevalence of indicators of pathogenic bacterial contaminants using DerSimonian and Laird’s approach with 95% confidence intervals ( CIs ) [ 28 ]. The inverse of the Freeman-Tukey double arcsine transformation was used to stabilize the variance of each study [ 29 ].

A forest plot was generated to visually assess the pooled prevalence estimates and corresponding 95% confidence intervals ( CIs ) across the included studies. For statistical heterogeneity across studies, the I 2 statistic was used [ 30 ]. Heterogeneity was considered high, moderate, or low, with I 2 values of 75, 50, and 25%, respectively. To identify potential sources of heterogeneity, subgroup analyses were conducted in under-five children’s availability, seasons, residential, water sources, and regional settings. Publication bias was assessed by visual inspection of the funnel plot and tested by the Egger regression test [ 31 , 32 ].

Search results

A total of 992 articles were identified from the nine databases, and an additional 14 articles were identified through additional manual searching. Three hundred forty-two studies were removed due to being duplicates found both within the same database and across different databases. A total of 616 studies were determined to be ineligible during title and abstract screening. At the full-text review stage, 27 articles were excluded because they did not measure microbial indicators of interest. The flow chart of the study selection process is presented in Fig.  1 , generated using the PRISMA flow diagram [ 33 ].

Flow diagram indicating how articles were included and excluded during the meta-analysis of household drinking water contamination in Ethiopia

Characteristics of the included studies

This study included 16 studies with 4,193 samples for fecal coliform [ 17 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ], and eight studies with 2,594 samples for E. coli analysis [ 38 , 46 , 48 , 49 , 50 , 51 , 52 , 53 ]. The main characteristics of the selected studies are summarized in the article matrix [S2]. All the articles were cross-sectional studies and followed a random sampling procedure. The articles included in the study were conducted between 2013 and 2023 and sample sizes ranged from 42 to 538 for E. coli and from 42 to 736 for fecal coliforms.

The data were collected from seven regions of Ethiopia. Nine studies in Amhara region [ 35 , 36 , 40 , 42 , 43 , 44 , 45 , 49 , 51 ], one study each in Sidama [ 47 ], Somali [ 53 ] and Gambela [ 41 ] regions, two studies each in Oromia [ 17 , 46 ], and Tigray [ 34 , 38 ] regions, four studies in SNNPR [ 37 , 39 , 48 , 52 ], and one study in all over Ethiopia [ 50 ] were conducted. Moreover, six studies were conducted in households with under-five children only [ 41 , 42 , 44 , 49 , 51 , 53 ].

Pooled meta-analysis

The forest plot of the prevalence estimates and the corresponding 95% confidence intervals ( CIs ) of the contaminants are presented in Figs.  2 and 3 . The pooled prevalence of fecal coliform was 63.7% (95% CI: 56.0–71.0%, I 2  = 95.8%, based on 16 studies) in a total sample of 4193 households. Additionally, the pooled prevalence of E. coli was 54.0 (95% CI: 45.7–62.3%, I 2  = 94.2%, based on 8 studies) in a total sample of 2,594 households. The funnel plot [ S3 ] showed almost no publication bias, which was confirmed by the Egger regression test for both fecal coliform ( p  = 0.10) and E. coli ( p  = 0.18). Moreover, no publication bias was confirmed by the ‘Trim and Fill’ sensitivity analysis, as we did not find any hypothetical missing studies. A leave-one-out sensitivity analysis found that excluding any single study resulted in an average variation of 1% in the pooled prevalence of fecal coliforms and 1.93% for E. coli , indicating no substantial impact on the overall results.

Forest plot of the prevalence of fecal coliform bacteria in households drinking water in Ethiopia

Forest plot of the prevalence of E. coli in households drinking water in Ethiopia

Heterogeneity and subgroup analysis

The pooled prevalence of fecal coliform among the dry seasons samples was 60.1% (95% CI: 47.4–72.1), while for the wet seasons samples, it was 70.3% (95% CI: 63.8–76.3). When stratified by residence, the pooled prevalence in rural and urban areas were 68.0% [95%CI: 59.0–76.3] and 66.4% [95%CI: 49.1–81.7], respectively. Specifically, households with under-five children had a higher prevalence of fecal coliform (73.8% [95% CI: 63.9–82.7%]) than all households without any restrictions (61.0% [95% CI: 51.8–69.8]). When stratified by regions, the prevalence of fecal coliform was highest (71.4%) in Amhara, 71.2% in Gambela, and 70.1% in Oromia, compared with 58.1% in SNNP, 31.7% in Sidama, and 42.0% in Tigray. Regarding sample collection sources, the prevalence of fecal coliform is higher at the point of use (66.4% [95% CI: 57.3–74.9]) compared to the point of source (57.8% [95% CI: 42.0-72.3]). No significant publication bias was observed in any of the subgroup analyses (Table  1 ).

The pooled prevalence of E. coli (Fig.  4 ) among only households with under-five children was 65.9% (95% CI: 57.9–73.4), while for all households, it was 45.9% (95% CI: 35.2–56.9). The detailed distribution of the pooled prevalence of E. coli in household drinking water is shown in a table [ S4 ].

Forest plot of E. coli prevalence distribution in all households and only households with under-five children drinking water in Ethiopia

This systematic review and meta-analysis aimed to compile all available data reporting the prevalence and epidemiological distribution of indicators of pathogenic bacteria in households’ drinking water in Ethiopia. The study findings help enhance public health interventions in Ethiopia by identifying vulnerable groups and suggesting appropriate measures to reduce the impact of waterborne diseases. This knowledge enables more targeted interventions to mitigate the effects of such diseases effectively. The findings of this systematic review and meta-analysis revealed that the pooled prevalence of fecal coliforms in households’ drinking water in the 16 cross-sectional studies with 4193 samples was 63.7% (95% CI: 56.0, 71.0%).

This is lower than that found in a similar systematic review and meta-analysis in developing countries, where the fecal contamination of household drinking water was 75% (95% CI: 64, 84%) [ 54 ]. Differently, this is comparably high compared to the pooled prevalence in Africa (53%, 95% CI: 42, 63%); and also, significantly higher than the study conducted in South-East Asia (35%, 95% CI: 24, 45%) [ 55 ]. This variation might come from differences in how samples are collected and could also be because South-East Asia has better water quality rules and improvements compared to Ethiopia. In addition, the pooled prevalence of E. coli in households’ drinking water in the 8 cross-sectional studies with a total of 2,594 samples was 54% (95% CI: 45.7, 62.3%). This pooled prevalence is lower than a systematic review and meta-analysis conducted in Africa (2000–2021) where the pooled prevalence of E. coli in drinking water was 71.7% (95% CI: 56.2, 83.3%) [ 56 ]. Regional variations in water contamination in Ethiopia, compared to other African countries, can be influenced by factors like the types of water sources, the effectiveness of sanitation and water treatment practices, local environmental conditions, and differences in public health standards.

In this study, the prevalence of fecal coliform in households drinking water in the wet season was higher (70.3%) than in the dry season (60.1%). Similarly, a study conducted in Ghana found that the proportion of the population at risk of fecal contamination in the rainy season (41.5%) was higher compared to the dry season (33.1%) [ 57 ]. Furthermore, the pooled prevalence of fecal coliform was higher (73.8%) among households with only under-five children than in other households, this might be because of improper disposal of child feces. The pooled prevalence of fecal coliform was lower (66.4%) among urban households than rural (68%). Similarly, a systematic review and meta-analysis study on fecal contamination of drinking water globally, and in low-and-middle-income countries found that drinking water is more contaminated in rural areas than in urban areas [ 55 , 58 ]. This might be because urban areas have better infrastructure, like improved water sources and improved sanitation, which help to keep lower contamination levels.

Finally, the pooled prevalence of fecal coliform was higher at the point of use (66.4%) compared to the source point (57.8%). Similarly, a study conducted in Bangladesh found a lower contamination rate of 28% in water samples taken from the source compared to a significantly higher contamination rate of 73.96% in samples from stored household sources (point of use) [ 59 ]. The higher pooled prevalence of contamination observed in stored household water, compared to source water, is likely due to poor storage conditions, inadequate hygiene practices, and exposure to environmental contaminants. Future research should explore how Ethiopian water management practices and infrastructure impact fecal coliform and E. coli prevalence to identify effective interventions. Longitudinal studies could track changes in water quality over time. Additionally, more research in underrepresented regions is needed to understand water contamination patterns and improve policies for safer drinking water in Ethiopia.

The findings of this systematic review and meta-analysis point to a higher prevalence of E. coli and fecal coliform in Ethiopia, raising serious concerns about public health that require attention. There are variations within the country by season, residence, region, sources of sample collection and availability of under-five children. Subgroup assessments revealed an increased risk during the wet season, among only households with under-five children, at point-of-use, residing in rural areas, notably in the Amhara, Gambella, and Oromia regions. These findings emphasize the critical necessity for targeted interventions in vulnerable populations and specific geographic areas to address the risks posed by drinking water contamination and improve public health outcomes promptly.

Strengths and limitations of this study

We employed appropriate methods to stabilize variability across studies and enhance the reliability of our overall findings. The generalizability of our study might be constrained because of the restricted regional coverage within the country.

Data availability

No datasets were generated or analysed during the current study.

WHO. (2021). A global overview of national regulations and standards for drinking-water quality.

WHO and UNICEF. Progress on Drinking Water, Sanitation and Hygiene: 2017 Update and SDG Baselines, World Health Organization, Geneva, Switzerland , 2017.

UN. 2016., Transforming our world: The 2030 agenda for sustainable development.

UN. 2020., The sustainable development goals report 2020.

WHO., Drinking Water: Key Facts, WHO, Geneva, Switzerland,. 2020, https://www.who.int/en/news-room/fact-sheets/detail/drinking-water.

Simon AK, Hollander GA, McMichael A. Evolution of the immune system in humans from infancy to old age. Proc Biol Sci. 2015;282(1821). https://doi.org/10.1098/rspb.2014.3085 .

Ford TE, Hamner S. A perspective on the global pandemic of Waterborne Disease. Microb Ecol. 2018;76(1):2–8.

Article   PubMed   Google Scholar  

Momtaz H, Dehkordi FS, Rahimi E, Asgarifar A. Detection of Escherichia coli, Salmonella species, and Vibrio cholerae in tap water and bottled drinking water in Isfahan, Iran. BMC Public Health. 2013;13. https://doi.org/10.1186/1471-2458-13-556 .

WHO., Diarrhoeal disease, 7 March. 2024. https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease.

Gwimbi P, George M, Ramphalile M. Bacterial contamination of drinking water sources in rural villages of Mohale Basin, Lesotho: exposures through neighbourhood sanitation and hygiene practices. Environ Health Prev Med. 2019;24(1). https://doi.org/10.1186/s12199-019-0790-z .

Ladokun OA, Oni SO. Physico-Chemical and Microbiological Analysis of Potable Water in Jericho and Molete areas of Ibadan Metropolis. Adv Biol Chem. 2015;05:197–202.

Article   Google Scholar  

Abebe B, Dejene, Hailu. Bacteriological and Physicochemical Quality of Drinking Water Sources and Household Water Handling Practice among Rural communities of Bona District, Sidama Zone-Zouthern, Ethiopia. Sci J Public Health. 2015;3(5). https://doi.org/10.11648/j.sjph.20150305.37 .

Girmay AM, et al. Associations of WHO/UNICEF Joint Monitoring Program (JMP) Water, Sanitation and Hygiene (WASH) Service Ladder service levels and sociodemographic factors with diarrhoeal disease among children under 5 years in Bishoftu town, Ethiopia: a cross-sectional study. BMJ open. 2023;13(7):e071296.

Article   PubMed   PubMed Central   Google Scholar  

WHO. Guidelines for drinking-water quality: First Addendum to the Fourth Edition. 4th ed. Geneva, Switzerland: World Health Organization; 2017b.

Google Scholar  

Legesse T, Dessie W, Abera F, Gobena W, Girma S, Muzeyin R, Gonfa A, Desta K. Virological and bacteriological quality of drinking water in Ethiopia. Int J Infect Dis. 2018;73. https://doi.org/10.1016/j.ijid.2018.04.3909 .

WHO. Water, Sanitation and Hygiene Links to Health, Facts and Figures, World Health Organization, Geneva, 2004.

Amenu D, Gobena. SMT. Assessment of water handling practices among rural communities of dire dawa administrative council, dire dawa, Ethiopia. Sci Techn Arts Res J. 2013;2(2). https://doi.org/10.4314/star.v2i2.98891 .

Fufa BK, Liben M, Dessalegn. Bacteriological quality of drinking tap water in selected districts of north showa zone, Amhara, Ethiopia. Archives Appl Sci Res. 2016;8:23–7.

CAS   Google Scholar  

Yasin M, Bacha KT. Physico-chemical and bacteriological quality of drinking water of different sources, Jimma Zone, Southwest Ethiopia. BMC Res Notes. 2015;8:541. Epub 2015/10/07.

Tsega N, Sahile S, Kibret M, Abera B. Bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia. Afr Health Sci. 2013;13(4). https://doi.org/10.4314/ahs.v13i4.42 .

Mengesha A, Baye MW. A survey of bacteriological quality of drinking water in North Gondar. Ethiop J Health Dev. 2004;18(2):112–5.

Girmay AM, et al. Access to water, sanitation and hygiene (WASH) services and drinking water contamination risk levels in households of Bishoftu Town, Ethiopia: a cross-sectional study. Health Sci Rep. 2023;6(11):e1662.

Banda K, Sarkar R, Gopal S, Govindarajan J, Harijan BB, Jeyakumar MB, et al. Water handling, sanitation and defecation practices in rural southern India: a knowledge, attitudes and practices study. Trans R Soc Trop Med Hyg. 2007;101(11):1124–30.

Meride Y. Drinking water quality assessment and its effects on residents health in Wondo Genet campus. Ethiopia Environ Sys Res. 2016;5(1):1.

Adane M, Mengistie B, Medhin G, Kloos H, Mulat W. Piped water supply interruptions and acute diarrhea among under-five children in Addis Ababa slums, Ethiopia: a matched case-control study. PLoS One, 12, e0181516. (2017).

Chalchisa D, Megersa M, Beyene A. Assessment of the quality of drinking water in storage tanks and its implication on the safety of urban water supply in developing countries. Environ Syst Res. 2017;6:12. https://doi.org/10.1186 .

von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The strengthening the reporting of Observational studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Ann Intern Med. 2007;147(8):573–7.

Barendregt JJ, Doi SA, Lee YY, Norman RE, Vos T. Meta-analysis of prevalence. J Epidemiol Community Health. 2013;67(11):974–8.

Cochran WG. The combination of estimates from different experiments. Biometrics. 1954;10:101–29.

Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med. 2002;21(11):1539–58.

Duval S, Tweedie R. Trim and fill: a simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis. Biometrics. 2000;56(2):455–63.

Article   PubMed   CAS   Google Scholar  

Egger M, Davey Smith G, Schneider M, Minder C. Bias in meta-analysis detected by a simple, graphical test. BMJ. 1997;315(7109):629–34.

Article   PubMed   PubMed Central   CAS   Google Scholar  

Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097.

Baye Sitotaw and Molla Nigus. Bacteriological and physicochemical quality of drinking water in Kobo town, Northern Ethiopia. Journal of Water, Sanitation and Hygiene for Development; 2021. 11.2.

Sitotaw B, Geremew M. Bacteriological and Physicochemical Quality of Drinking Water in Adis Kidame Town, Northwest Ethiopia. Int J Microbiol. 2021;2021. https://doi.org/10.1155/2021/6669754 .

Sitotaw B, Melkie E, Temesgen D. Bacteriological and Physicochemical Quality of Drinking Water in Wegeda Town, Northwest Ethiopia. J Environ Public Health. 2021;2021. https://doi.org/10.1155/2021/6646269 .

Gizachew M, Admasie A, Wegi C, Assefa E. Bacteriological Contamination of Drinking Water Supply from Protected Water sources to point of Use and Water Handling practices among Beneficiary households of Boloso Sore Woreda, Wolaita Zone, Ethiopia. Int J Microbiol. 2020;2020. https://doi.org/10.1155/2020/5340202 .

Gebrewahd A, Adhanom G, Gebremichail G, Kahsay T, Berhe B, Asfaw Z, et al. Bacteriological quality and associated risk factors of drinking water in Eastern Zone, Tigrai, Ethiopia, 2019. Trop Dis Travel Med Vaccines. 2020;6. https://doi.org/10.1186/s40794-020-00116-0 .

Zemachu A et al. Bacteriological Quality of Drinking Water and Associated Factors at the Internally Displaced People Sites, Gedeo Zone, Southern Ethiopia: A Cross-sectional StudyEnvironmental Health Insights Volume 15: 1–6 2021 DOI: 10.1177/11786302211026469.

Getachew A, Tadie A, Chercos DH, Guadu T, Alemayehu M, Gizaw, Zemichael MG, Hiwot, Cherkos TG. Bacteriological quality of household drinking water in North Gondar Zone, Ethiopia; a community-based cross-sectional study. Appl Water Sci. 2021;11(12). https://doi.org/10.1007/s13201-021-01515-0 .

Mekonnen GK, Mengistie B, Sahilu G, Mulat W, Kloos, Helmut. Determinants of microbiological quality of drinking water in refugee camps and host communities in Gambella Region, Ethiopia. J Water Sanitation Hygiene Dev. 2019;9(4):671–82.

Berihun G, Hassen AM, Gizeyatu S, Berhanu A, Teshome L, Walle D, Desye Z, Sewunet B. B and Keleb A Drinking water contamination potential and associated factors among households with under-five children in rural areas of Dessie Zuria District, Northeast Ethiopia. Front. Public Health 11:1199314. doi: 10.3389/fpubh. 2023. 1199314. (2023).

Birhan TA, Bitew BD, Dagne H, Amare DE, Azanaw J, Andualem Z, et al. Household drinking water quality and its predictors in flood-prone settings of Northwest Ethiopia: a cross-sectional community-based study. Heliyon. 2023;9(4):e15072.

Feleke H, Medhin G, Kloos H, Gangathulasi J, Asrat D. Household-stored drinking water quality among households of under-five children with and without acute diarrhea in towns of Wegera District, in North Gondar, Northwest Ethiopia. Environ Monit Assess. 2018;190(11). https://doi.org/10.1007/s10661-018-7033-4 .

Getachew A, Tadie A, Chercos DH, Guadu T. Level of Faecal Coliform Contamination of Drinking Water Sources and its Associated Risk factors in rural settings of North Gondar Zone, Ethiopia: a cross-sectional community based study. Ethiop J Health Sci. 2018;28(2):227–34.

Edessa N, Geritu N, Mulugeta K. Microbiological assessment of drinking water with reference to diarrheagenic bacterial pathogens in Shashemane Rural District, Ethiopia, Vol. 11(6), pp. 254–263, 14 February , 2017 DOI: 10.5897/AJMR2016.8362.

Robel SB, Mohammed AT. Physicochemical and microbial quality of drinking water in slum households of Hawassa City. Ethiopia Appl Water Sci (2023) 134 https://doi.org/10.1007/s13201-022-01806-0

Dhengesu D, Lemma H, Asefa L, Tilahun D. Antimicrobial Resistance Profile of Enterobacteriaceae and drinking Water Quality among households in Bule Hora Town, South Ethiopia. Risk Manag Healthc Policy. 2022;15. https://doi.org/10.2147/rmhp.s370149 .

Usman MA, Gerber, Nicolas. Irrigation, drinking water quality, and child nutritional status in northern Ethiopia. J Water Sanitation Hygiene Dev. 2020;10(3). https://doi.org/10.2166/washdev.2020.045 .

Usman MA, Gerber N, Pangaribowo, Evita H. Drivers of microbiological quality of household drinking water – a case study in rural Ethiopia. J Water Health. 2017;16(2). https://doi.org/10.2166/wh.2017.069 .

Gizaw Z, Yalew AW, Bitew BD, Lee J, Bisesi M. Fecal indicator bacteria along multiple environmental exposure pathways (water, food, and soil) and intestinal parasites among children in the rural northwest Ethiopia. BMC Gastroenterol, 2022. 22(1): p.: https://doi.org/10.1186/s12876-022-02174-4

Alemayehu TA, Weldetinsae A, Dinssa DA, Derra FA, Bedada TL, Asefa YB, et al. Sanitary condition and its microbiological quality of improved water sources in the Southern Region of Ethiopia. Environ Monit Assess. 2020;192(5). https://doi.org/10.1007/s10661-020-08297-z .

Muhummed AM, Osman Y, Abdillahi R, Hattendorf J, Zinsstag J, Tschopp, Rea, Cissé G. Water Quality, Sanitation, Hygiene, and Diarrheal Diseases among Children in Adadle District, Somali Region, Eastern Ethiopia . 2023, Research Square(unpublished).

Shields KF, et al. Association of supply type with fecal contamination of source water and household stored drinking water in developing countries: a bivariate meta-analysis. Environ Health Perspect. 2015;123(12):1222–31.

Bain R, Cronk R, Hossain R, Bonjour S, Onda K, Wright J, et al. Global assessment of exposure to faecal contamination through drinking water based on a systematic review. Trop Med Int Health. 2014;19(8):917–27.

Ramatla T, Ramaili T, Lekota KE, Ndou R, Mphuti N, Bezuidenhout, Carlos and, Thekisoe O. A systematic review and meta-analysis on prevalence and antimicrobial resistance profile of Escherichia coli isolated from water in africa (2000–2021). Heliyon, 2023: p.: https://doi.org/10.1016/j.heliyon.2023.e16123

Dongzagla A, Jewitt S, Hara O. Seasonality in faecal contamination of drinking water sources in the Jirapa and Kassena-Nankana municipalities of Ghana. Sci Total Environ. 2021;752. https://doi.org/10.1016/j.scitotenv.2020.141846 .

Bain R, Cronk R, Wright J, Yang H, Slaymaker T, Bartram J. Fecal contamination of drinking-water in low- and middle-income countries: a systematic review and meta-analysis. PLoS Med. 2014;11(5):e1001644.

Mahmud ZH, Islam MS, Imran KM, Worth HSAI, Ahmed M. Occurrence of Escherichia coli and faecal coliforms in drinking water at source and household point-of-use in Rohingya camps, Bangladesh. Gut Pathogens. 2019;11(1):52.

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Drinking water quality assessment and its effects on residents health in Wondo genet campus, Ethiopia

• Yirdaw Meride 1 &
• Bamlaku Ayenew 1  

Environmental Systems Research volume  5 , Article number:  1 ( 2016 ) Cite this article

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Water is a vital resource for human survival. Safe drinking water is a basic need for good health, and it is also a basic right of humans. The aim of this study was to analysis drinking water quality and its effect on communities residents of Wondo Genet.

The mean turbidity value obtained for Wondo Genet Campus is (0.98 NTU), and the average temperature was approximately 28.49 °C. The mean total dissolved solids concentration was found to be 118.19 mg/l, and EC value in Wondo Genet Campus was 192.14 μS/cm. The chloride mean value of this drinking water was 53.7 mg/l, and concentration of sulfate mean value was 0.33 mg/l. In the study areas magnesium ranges from 10.42–17.05 mg/l and the mean value of magnesium in water is 13.67 mg/l. The concentration of calcium ranges from 2.16–7.31 mg/l with an average value of 5.0 mg/l. In study areas, an average value of sodium was 31.23 mg/1and potassium is with an average value of 23.14 mg/1. Water samples collected from Wondo Genet Campus were analyzed for total coliform bacteria and ranged from 1 to 4/100 ml with an average value of 0.78 colony/100 ml.

On the basis of findings, it was concluded that drinking water of the study areas was that all physico–chemical parameters. All the Campus drinking water sampling sites were consistent with World Health Organization standard for drinking water (WHO).

Safe drinking water is a basic need for good health, and it is also a basic right of humans. Fresh water is already a limiting resource in many parts of the world. In the next century, it will become even more limiting due to increased population, urbanization, and climate change (Jackson et al. 2001 ).

Drinking water quality is a relative term that relates the composition of water with effects of natural processes and human activities. Deterioration of drinking water quality arises from introduction of chemical compounds into the water supply system through leaks and cross connection (Napacho and Manyele 2010 ).

Access to safe drinking water and sanitation is a global concern. However, developing countries, like Ethiopia, have suffered from a lack of access to safe drinking water from improved sources and to adequate sanitation services (WHO 2006 ). As a result, people are still dependent on unprotected water sources such as rivers, streams, springs and hand dug wells. Since these sources are open, they are highly susceptible to flood and birds, animals and human contamination (Messeret 2012 ).

The quality of water is affected by an increase in anthropogenic activities and any pollution either physical or chemical causes changes to the quality of the receiving water body (Aremu et al. 2011 ). Chemical contaminants occur in drinking water throughout the world which could possibly threaten human health. In addition, most sources are found near gullies where open field defecation is common and flood-washed wastes affect the quality of water (Messeret 2012 ).

The World Health Organization estimated that up to 80 % of all sicknesses and diseases in the world are caused by inadequate sanitation, polluted water or unavailability of water (WHO 1997 ). A review of 28 studies carried out by the World Bank gives the evidence that incidence of certain water borne, water washed, and water based and water sanitation associated diseases are related to the quality and quantity of water and sanitation available to users (Abebe 1986 ).

In Ethiopia over 60 % of the communicable diseases are due to poor environmental health conditions arising from unsafe and inadequate water supply and poor hygienic and sanitation practices (MOH 2011 ). About 80 % of the rural and 20 % of urban population have no access to safe water. Three-fourth of the health problems of children in the country are communicable diseases arising from the environment, specially water and sanitation. Forty-six percent of less than 5 years mortality is due to diarrhea in which water related diseases occupy a high proportion. The Ministry of Health, Ethiopia estimated 6000 children die each day from diarrhea and dehydration (MOH 2011 ).

There is no study that was conducted to prove the quality water in Wondo Genet Campus. Therefore, this study is conducted at Wondo Genet Campus to check drinking water quality and to suggest appropriate water treated mechanism.

Results and discussions

The turbidity of water depends on the quantity of solid matter present in the suspended state. It is a measure of light emitting properties of water and the test is used to indicate the quality of waste discharge with respect to colloidal matter. The mean turbidity value obtained for Wondo Genet Campus (0.98 NTU) is lower than the WHO recommended value of 5.00 NTU.

Temperature

The average temperature of water samples of the study area was 28.49 °C and in the range of 28–29 °C. Temperature in this study was found within permissible limit of WHO (30 °C). Ezeribe et al. ( 2012 ) reports similar result (29 °C) of well water in Nigeria.

Total dissolved solids (TDS)

Water has the ability to dissolve a wide range of inorganic and some organic minerals or salts such as potassium, calcium, sodium, bicarbonates, chlorides, magnesium, sulfates etc. These minerals produced un-wanted taste and diluted color in appearance of water. This is the important parameter for the use of water. The water with high TDS value indicates that water is highly mineralized. Desirable limit for TDS is 500 mg/l and maximum limit is 1000 mg/l which prescribed for drinking purpose. The concentration of TDS in present study was observed in the range of 114.7 and 121.2 mg/l. The mean total dissolved solids concentration in Wondo Genet campus was found to be 118.19 mg/l, and it is within the limit of WHO standards. Similar value was reported by Soylak et al. ( 2001 ), drinking water of turkey. High values of TDS in ground water are generally not harmful to human beings, but high concentration of these may affect persons who are suffering from kidney and heart diseases. Water containing high solid may cause laxative or constipation effects. According to Sasikaran et al. ( 2012 ).

Electrical conductivity (EC)

Pure water is not a good conductor of electric current rather’s a good insulator. Increase in ions concentration enhances the electrical conductivity of water. Generally, the amount of dissolved solids in water determines the electrical conductivity. Electrical conductivity (EC) actually measures the ionic process of a solution that enables it to transmit current. According to WHO standards, EC value should not exceeded 400 μS/cm. The current investigation indicated that EC value was 179.3–20 μS/cm with an average value of 192.14 μS/cm. Similar value was reported by Soylak et al. ( 2001 ) drinking water of turkey. These results clearly indicate that water in the study area was not considerably ionized and has the lower level of ionic concentration activity due to small dissolve solids (Table 1 ).

PH of water

PH is an important parameter in evaluating the acid–base balance of water. It is also the indicator of acidic or alkaline condition of water status. WHO has recommended maximum permissible limit of pH from 6.5 to 8.5. The current investigation ranges were 6.52–6.83 which are in the range of WHO standards. The overall result indicates that the Wondo Genet College water source is within the desirable and suitable range. Basically, the pH is determined by the amount of dissolved carbon dioxide (CO 2 ), which forms carbonic acid in water. Present investigation was similar with reports made by other researchers’ study (Edimeh et al. 2011 ; Aremu et al. 2011 ).

Chloride (Cl)

Chloride is mainly obtained from the dissolution of salts of hydrochloric acid as table salt (NaCl), NaCO 2 and added through industrial waste, sewage, sea water etc. Surface water bodies often have low concentration of chlorides as compare to ground water. It has key importance for metabolism activity in human body and other main physiological processes. High chloride concentration damages metallic pipes and structure, as well as harms growing plants. According to WHO standards, concentration of chloride should not exceed 250 mg/l. In the study areas, the chloride value ranges from 3–4.4 mg/l in Wondo Genet Campus, and the mean value of this drinking water was 3.7 mg/l. Similar value was reported by Soylak et al. ( 2001 ) drinking water of Turkey.

Sulfate mainly is derived from the dissolution of salts of sulfuric acid and abundantly found in almost all water bodies. High concentration of sulfate may be due to oxidation of pyrite and mine drainage etc. Sulfate concentration in natural water ranges from a few to a several 100 mg/liter, but no major negative impact of sulfate on human health is reported. The WHO has established 250 mg/l as the highest desirable limit of sulfate in drinking water. In study area, concentration of sulfate ranges from 0–3 mg/l in Wondo Genet Campus, and the mean value of SO 4 was 0.33 mg/l. The results exhibit that concentration of sulfate in Wondo Genet campus was lower than the standard limit and it may not be harmful for human health.

Magnesium (Mg)

Magnesium is the 8th most abundant element on earth crust and natural constituent of water. It is an essential for proper functioning of living organisms and found in minerals like dolomite, magnetite etc. Human body contains about 25 g of magnesium (60 % in bones and 40 % in muscles and tissues). According to WHO standards, the permissible range of magnesium in water should be 50 mg/l. In the study areas magnesium was ranges from 10.42 to 17.05 mg/l in Wondo Genet Campus and the mean value of magnesium in water is 13.67 mg/l. Similar value was reported by Soylak et al. ( 2001 ) drinking water of Turkey. The results exhibit that concentration of magnesium in Wondo Genet College was lower than the standard limit of WHO.

Calcium (Ca)

Calcium is 5th most abundant element on the earth crust and is very important for human cell physiology and bones. About 95 % of calcium in human body stored in bones and teeth. The high deficiency of calcium in humans may caused rickets, poor blood clotting, bones fracture etc. and the exceeding limit of calcium produced cardiovascular diseases. According to WHO ( 2011 ) standards, its permissible range in drinking water is 75 mg/l. In the study areas, results show that the concentration of calcium ranges from 2.16 to 7.31 mg/l in Wondo Genet campus with an average value of 5.08 mg/l.

Sodium (Na)

Sodium is a silver white metallic element and found in less quantity in water. Proper quantity of sodium in human body prevents many fatal diseases like kidney damages, hypertension, headache etc. In most of the countries, majority of water supply bears less than 20 mg/l, while in some countries the sodium quantity in water exceeded from 250 mg/l (WHO 1984 ). According to WHO standards, concentration of sodium in drinking water is 200 mg/1. In the study areas, the finding shows that sodium concentration ranges from 28.54 to 34.19 mg/1 at Wondo Genet campus with an average value of 31.23.

Potassium (k)

Potassium is silver white alkali which is highly reactive with water. Potassium is necessary for living organism functioning hence found in all human and animal tissues particularly in plants cells. The total potassium amount in human body lies between 110 and 140 g. It is vital for human body functions like heart protection, regulation of blood pressure, protein dissolution, muscle contraction, nerve stimulus etc. Potassium is deficient in rare but may led to depression, muscle weakness, heart rhythm disorder etc. According to WHO standards the permissible limit of potassium is 12 mg/1. Results show that the concentration of potassium in study areas ranges from 20.83 to 27.51 mg/1. Wondo Genet College with an average value of 23.14 mg/1. Present investigation was similar with reports made by other researchers’ study (Edimeh et al. 2011 ; Aremu et al. 2011 ). These results did not meet the WHO standards and may become diseases associated from potassium extreme surpassed.

Nitrate (NO 3 )

Nitrate one of the most important diseases causing parameters of water quality particularly blue baby syndrome in infants. The sources of nitrate are nitrogen cycle, industrial waste, nitrogenous fertilizers etc. The WHO allows maximum permissible limit of nitrate 5 mg/l in drinking water. In study areas, results more clear that the concentration of nitrate ranges from 1.42 to 4.97 mg/l in Wondo Genet campus with an average value of 2.67 mg/l. These results indicate that the quantity of nitrate in the study site is acceptable in Wondo Genet campus (Table 2 ).

Bacterial contamination

The total coliform group has been selected as the primary indicator bacteria for the presence of disease causing organisms in drinking water. It is a primary indicator of suitability of water for consumption. If large numbers of coliforms are found in water, there is a high probability that other pathogenic bacteria or organisms exist. The WHO and Ethiopian drinking water guidelines require the absence of total coliform in public drinking water supplies.

In this study, all sampling sites were not detected of faecal coliform bacteria. Figure  1 shows the mean values of total coliform bacteria in drinking water collected from the study area. All drinking water samples collected from Wondo Genet Campus were analyzed for total coliform bacteria and ranged from 1 to 4/100 ml with an average value of 0.78 colony/100 ml. In Wondo Genet College, the starting point of drinking water sources (Dam1), the second (Dam2) and Dam3 samples showed the presence of total coliform bacteria (Fig.  1 ). According to WHO ( 2011 ) risk associated in Wondo Genet campus drinking water is low risk (1–10 count/100 ml).

The mean values of total coliform bacteria in drinking water

According to the study all water sampling sites in Wondo Genet campus were meet world health organization standards and Ethiopia drinking water guideline. Figure  2 indicated that mean value of the study sites were under the limit of WHO standards.

Comparison of water quality parameters of drinking water of Wondo Genet campus with WHO and Ethiopia standards

Effect of water quality for residence health’s

Diseases related to contamination of drinking-water constitute a major burden on human health. Interventions to improve the quality of drinking-water provide significant benefits to health. Water is essential to sustain life, and a satisfactory (adequate, safe and accessible) supply must be available to all (Ayenew 2004 ).

Improving access to safe drinking-water can result in tangible benefits to health. Every effort should be made to achieve a drinking-water quality as safe as practicable. The great majority of evident water-related health problems are the result of microbial (bacteriological, viral, protozoan or other biological) contamination (Ayenew 2004 ).

Excessive amount of physical, chemical and biological parameters accumulated in drinking water sources, leads to affect human health. As discussed in the result, all Wondo Genet drinking water sources are under limit of WHO and Ethiopian guideline standards. Therefore, the present study was found the drinking water safe and no residence health impacts.

On the basis of findings, it was concluded that drinking water of the study areas was that all physico–chemical parameters in all the College drinking water sampling sites, and they were consistent with World Health Organization standard for drinking water (WHO). The samples were analyzed for intended water quality parameters following internationally recognized and well established analytical techniques.

It is evident that all the values of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), SO 4 , and NO 3 fall under the permissible limit and there were no toxicity problem. Water samples showed no extreme variations in the concentrations of cations and anions. In addition, bacteriological determination of water from College drinking water sources was carried out to be sure if the water was safe for drinking and other domestic application. The study revealed that all the College water sampling sites were not contained fecal coliforms except the three water sampling sites had total coliforms.

The study was conducted in Wondo Genet College of Forestry and Natural Resources campus, which is located in north eastern direction from the town of Hawassa and about 263 km south of Addis Ababa (Fig.  3 ). It lies between 38°37′ and 38°42′ East longitude and 7°02′ and 7°07′ north latitude. Landscape of the study area varies with an altitude ranging between 1600 and 2580 meters above sea level. Landscape of the study area varies with an altitude ranging between 1600 and 2580 meters above sea level.

Map of study area

The study area is categorized under Dega (cold) agro-ecological zone at the upper part and Woina Dega (temperate) agro-ecological zone at the lower part of the area. The rainfall distribution of the study area is bi-modal, where short rain falls during spring and the major rain comes in summer and stays for the first two months of the autumn season. The annual temperature and rainfall range from 17 to 19 °C and from 700 to 1400 mm, respectively (Wondo Genet office of Agriculture 2011).

Methodology

Water samples were taken at ten locations of Wondo Genet campus drinking water sources. Three water samples were taken at each water caching locations. Ten (10) water samples were collected from different locations of the Wondo Genet campus. Sampling sites for water were selected purposely which represents the entire water bodies.

Instead of this study small dam indicates the starting point of Wondo Genet campus drinking water sources rather than large dams constructed for other purpose. Taps were operated or run for at least 5 min prior to sampling to ensure collection of a representative sample (temperature and electrical conductivity were monitored to verify this). Each sample’s physico–chemical properties of water were measured in the field using portable meters (electrical conductivity, pH and temperature) at the time of sampling. Water samples were placed in clean containers provided by the analytical laboratory (glass and acid-washed polyethylene for heavy metals) and immediately placed on ice. Nitric acid was used to preserve samples for metals analysis.

Analysis of water samples

Determination of ph.

The pH of the water samples was determined using the Hanna microprocessor pH meter. It was standardized with a buffer solution of pH range between 4 and 9.

Measurement of temperature

This was carried out at the site of sample collection using a mobile thermometer. This was done by dipping the thermometer into the sample and recording the stable reading.

Determination of conductivity

This was done using a Jenway conductivity meter. The probe was dipped into the container of the samples until a stable reading will be obtained and recorded.

Determination of total dissolved solids (TDS)

This was measured using Gravimetric Method: A portion of water was filtered out and 10 ml of the filtrate measured into a pre-weighed evaporating dish. Filtrate water samples were dried in an oven at a temperature of 103 to 105 °C for \(2\frac{1}{2}\)  h. The dish was transferred into a desiccators and allowed cool to room temperature and were weighed.

In this formula, A stands for the weight of the evaporating dish + filtrate, and B stands for the weight of the evaporating dish on its own Mahmud et al. ( 2014 ).

Chemical analysis

Chloride concentration was determined using titrimetric methods. The chloride content was determined by argentometric method. The samples were titrated with standard silver nitrate using potassium chromate indicator. Calcium ions concentrations were determined using EDTA titrimetric method. Sulphate ions concentration was determined using colorimetric method.

Microorganism analysis

In the membrane filtration method, a 100 ml water sample was vacuumed through a filter using a small hand pump. After filtration, the bacteria remain on the filter paper was placed in a Petri dish with a nutrient solution (also known as culture media, broth or agar). The Petri dishes were placed in an incubator at a specific temperature and time which can vary according the type of indicator bacteria and culture media (e.g. total coliforms were incubated at 35 °C and fecal coliforms were incubated at 44.5 °C with some types of culture media). After incubation, the bacteria colonies were seen with the naked eye or using a magnifying glass. The size and color of the colonies depends on the type of bacteria and culture media were used.

Statically analysis

All data generated was analyzed statistically by calculating the mean and compare the mean value with the acceptable standards. Data collected was statistically analyzed using Statistical Package for Social Sciences (SPSS 20).

Abbreviations

ethylene dinitrilo tetra acetic acid

Minstor of Health

nephelometric turbidity units

total dissolved solid

World Health Organization

Abebe L (1986) Hygienic water quality; its relation to health and the testing aspects in tropical conditions. Department of Civil Engineering, University of Tempere, Finland

Aremu MO et al (2011) Physicochemical characteristics of stream, well and borehole water sources in Eggon, Nasarawa State, Nigeria. J Chem Soc Nigeria 36(1):131–136

Google Scholar  

Ayenew T (2004) Environmental implications of changes in the levels of lakes in the Ethiopian Rift since 1970. Reg Environ Chang 4:192–204

Article   Google Scholar  

Edimeh et al (2011) Physico-chemical parameters and some Heavy metals content of rivers Inachalo and Niger in Idah, Kogi State. J Chem Soc Nigeria 36(1):95–101

Ezeribe AL et al (2012) Physico-chemical properties of well water samples from some villages in Nigeria with cases of stained and mottle teeth. Sci World J 7(1):1–13

Jackson et al (2001) Water in changing world, Issues in Ecology. Ecol Soc Am, Washington, pp 1–16

Mahmud et al (2014) Surface water quality of Chittagong University campus, Bangladesh. J Environ Sci 8:2319-2399

Messeret B (2012) Assessment of drinking water quality and determinants of household potable water consumption in Simada district, ethiopia

MOH (2011) Knowledge, attitude and practice of water supply, environmental sanitation and hygiene practice in selected worked as of Ethiopia

Napacho A, Manyele V (2010) Quality assessment of drinking water in Temeke district (Part II): characterization of chemical parameters. Af J Environ Sci Technol 4(11):775–789

Sasikaran S et al (2012) Physical, chemical and microbial analysis of bottled drinking water. J Ceylon Medical 57(3):111–116

Soylak et al (2002) Chemical analysis of drinking water samples from Yozgat, Turkey. Polish J Environ Stud 11(2):151–156

WHO (1984) Guideline for drinking water quality. Health Criteria Support Inf 2:63–315

World Health Organization (1997) Basic Environmental Health, Geneva

World Health Organization (2004) Guidelines for drinking-water quality. World Health Organization, Geneva

World Health Organization (2006) In water, sanitation and health world health organization

WHO (2011) Guidelines for drinking-water quality, 4th edn. Geneva, Switzerland

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Authors’ contributions

YM: participated in designing the research idea, field data collection, data analysis, interpretation and report writing; BA: participated in field data collection, interpretation and report writing. Both authors read and approved the final manuscript.

Authors’ information

Yirdaw Meride: Lecturer at Hawassa University, Wondo Genet College of Forestry and Natural Resources. He teaches and undertakes research on solid waste, carbon sequestration and water quality. He has published three articles mainly in international journals. Bamlaku Ayenew: Lecturer at Hawassa University, Wondo Genet College of Forestry and Natural Resources. He teaches and undertakes research on Natural Resource Economics. He has published three article with previous author and other colleagues.

Acknowledgements

Hawassa University, Wondo Genet College of Forestry and Natural Resources provided financial support for field data collection and water laboratory analysis. The authors thank anonymous reviewers for constructive comments.

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Meride, Y., Ayenew, B. Drinking water quality assessment and its effects on residents health in Wondo genet campus, Ethiopia. Environ Syst Res 5 , 1 (2016). https://doi.org/10.1186/s40068-016-0053-6

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DOI : https://doi.org/10.1186/s40068-016-0053-6

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Time series analysis to estimate the volume of drinking water consumption in the city of meoqui, chihuahua, mexico.

1. Introduction

2. materials and methods, 2.1. research site, 2.2. junta municipal de aguas y saneamiento (jmas) of meoqui, chihuahua, 2.3. data collection.

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2.4. Data Analyses

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• Postel, S.L. Water and world population growth. J.-Am. Water Work. Assoc. 2000 , 92 , 131–138. [ Google Scholar ]
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• Buttinelli, R.; Cortignani, R.; Caracciolo, F. Irrigation water economic value and productivity: An econometric estimation for maize grain production in Italy. Agric. Water Manag. 2024 , 295 , 108757. [ Google Scholar ]
• Larraz, B.; García-Rubio, N.; Gámez, M.; Sauvage, S.; Cakir, R.; Raimonet, M.; Pérez, J.M.S. Socio-Economic Indicators for Water Management in the South-West Europe Territory: Sectorial Water Productivity and Intensity in Employment. Water 2024 , 16 , 959. [ Google Scholar ] [ CrossRef ]
• MacAllister, D.J. Groundwater Decline Is Global but not Universal ; Nature Publishing Group UK London: London, UK, 2024. [ Google Scholar ]
• Henao, C.; Lis-Gutiérrez, J.P.; Lis-Gutiérrez, M.; Ariza-Salazar, J. Determinants of efficient water use and conservation in the Colombian manufacturing industry using machine learning. Humanit. Soc. Sci. Commun. 2024 , 11 , 1–11. [ Google Scholar ]
• Environment Institute, S. 6 Clean Water and Sanitation. The Government of Sweden; 2024. Available online: https://www.government.se/government-policy/the-global-goals-and-the-2030-Agenda-for-sustainable-development/goal-6-clean-water-and-sanitation/ (accessed on 15 August 2024).
• El Garouani, M.; Radoine, H.; Lahrach, A.; Jarar Oulidi, H. Spatiotemporal Analysis of Groundwater Resources in the Saïss Aquifer, Morocco. Water 2022 , 15 , 105. [ Google Scholar ] [ CrossRef ]
• Roy, S.; Taloor, A.K.; Bhattacharya, P. A geospatial approach for understanding the spatio-temporal variability and projection of future trend in groundwater availability in the Tawi basin, Jammu, India. Groundw. Sustain. Dev. 2023 , 21 , 100912. [ Google Scholar ]
• Montgomery, M.A.; Elimelech, M. Water and sanitation in developing countries: Including health in the equation. Environ. Sci. Technol. 2007 , 41 , 17–24. [ Google Scholar ] [ PubMed ]
• Ochoa, C.G.; Villarreal-Guerrero, F.; Prieto-Amparán, J.A.; Garduño, H.R.; Huang, F.; Ortega-Ochoa, C. Precipitation, Vegetation, and Groundwater Relationships in a Rangeland Ecosystem in the Chihuahuan Desert, Northern Mexico. Hydrology 2023 , 10 , 41. [ Google Scholar ] [ CrossRef ]
• R Core Team. R: A Language and Environment for Statistical Computing ; R Foundation for Statistical Computing: Vienna, Austria, 2024. [ Google Scholar ]
• Robinson, D.; Hayes, A.; Couch, S. Broom: Convert Statistical Objects into Tidy Tibbles. 2024. Available online: https://CRAN.R-project.org/package=broom (accessed on 15 September 2024).
• Kuhn, M.; Frick, H. Dials: Tools for Creating Tuning Parameter Values. 2024. Available online: https://CRAN.R-project.org/package=dials (accessed on 15 September 2024).
• Wickham, H.; François, R.; Henry, L.; Müller, K.; Vaughan, D. Dplyr: A Grammar of Data Manipulation. 2023. Available online: https://CRAN.R-project.org/package=dplyr (accessed on 15 September 2024).
• Wickham, H. forcats: Tools for Working with Categorical Variables (Factors). 2023. Available online: https://CRAN.R-project.org/package=forcats (accessed on 15 September 2024).
• Wickham, H. Ggplot2: Elegant Graphics for Data Analysis ; Springer: New York, NY, USA, 2016; Available online: https://ggplot2.tidyverse.org (accessed on 15 September 2024).
• Couch, S.P.; Bray, A.P.; Ismay, C.; Chasnovski, E.; Baumer, B.S.; Çetinkaya-Rundel, M. infer: An R package for tidyverse-friendly statistical inference. J. Open Source Softw. 2021 , 6 , 3661. [ Google Scholar ]
• Grolemund, G.; Wickham, H. Dates and Times Made Easy with lubridate. J. Stat. Softw. 2011 , 40 , 1–25. [ Google Scholar ]
• Kuhn, M. modeldata: Data Sets Useful for Modeling Examples. 2024. Available online: https://CRAN.R-project.org/package=modeldata (accessed on 15 September 2024).
• Dancho, M. Modeltime: The Tidymodels Extension for Time Series Modeling. 2024. Available online: https://CRAN.R-project.org/package=modeltime (accessed on 15 September 2024).
• Aust, F.; Barth, M. Papaja: Prepare Reproducible APA Journal Articles with R Markdown. 2023. Available online: https://github.com/crsh/papaja (accessed on 15 September 2024).
• Kuhn, M.; Vaughan, D. Parsnip: A Common API to Modeling and Analysis Functions. 2024. Available online: https://CRAN.R-project.org/package=parsnip (accessed on 15 September 2024).
• Wickham, H.; Henry, L. Purrr: Functional Programming Tools. 2023. Available online: https://CRAN.R-project.org/package=purrr (accessed on 15 September 2024).
• Wickham, H.; Hester, J.; Bryan, J. Readr: Read Rectangular Text Data. 2024. Available online: https://CRAN.R-project.org/package=readr (accessed on 15 September 2024).
• Kuhn, M.; Wickham, H.; Hvitfeldt, E. Recipes: Preprocessing and Feature Engineering Steps for Modeling. 2024. Available online: https://CRAN.R-project.org/package=recipes (accessed on 15 September 2024).
• Wickham, H. Reshaping Data with the reshape Package. J. Stat. Softw. 2007 , 21 , 1–20. [ Google Scholar ]
• Frick, H.; Chow, F.; Kuhn, M.; Mahoney, M.; Silge, J.; Wickham, H. rsample: General Resampling Infrastructure. 2024. Available online: https://CRAN.R-project.org/package=rsample (accessed on 15 September 2024).
• Wickham, H.; Pedersen, T.L.; Seidel, D. Scales: Scale Functions for Visualization. 2023. Available online: https://CRAN.R-project.org/package=scales (accessed on 15 September 2024).
• Wickham, H. Stringr: Simple, Consistent Wrappers for Common String Operations. 2023. Available online: https://CRAN.R-project.org/package=stringr (accessed on 15 September 2024).
• Müller, K.; Wickham, H. Tibble: Simple Data Frames. 2023. Available online: https://CRAN.R-project.org/package=tibble (accessed on 15 September 2024).
• Kuhn, M.; Wickham, H. Tidymodels: A Collection of Packages for Modeling and Machine Learning Using Tidyverse Principles. 2020. Available online: https://www.tidymodels.org (accessed on 15 September 2024).
• Wickham, H.; Vaughan, D.; Girlich, M. Tidyr: Tidy Messy Data. 2024. Available online: https://CRAN.R-project.org/package=tidyr (accessed on 15 September 2024).
• Dancho, M.; Vaughan, D. Timetk: A Tool Kit for Working with Time Series. 2023. Available online: https://CRAN.R-project.org/package=timetk (accessed on 15 September 2024).
• Barth, M. Tinylabels: Lightweight Variable Labels. 2023. Available online: https://cran.r-project.org/package=tinylabels (accessed on 15 September 2024).
• Pohlert, T. Trend: Non-Parametric Trend Tests and Change-Point Detection. 2023. Available online: https://CRAN.R-project.org/package=trend (accessed on 15 September 2024).
• Kuhn, M. Tune: Tidy Tuning Tools. 2024. Available online: https://CRAN.R-project.org/package=tune (accessed on 15 September 2024).
• Vaughan, D.; Couch, S. Workflows: Modeling Workflows. 2024. Available online: https://CRAN.R-project.org/package=workflows (accessed on 15 September 2024).
• Kuhn, M.; Couch, S. Workflowsets: Create a Collection of “Tidymodels” Workflows. 2024. Available online: https://CRAN.R-project.org/package=workflowsets (accessed on 15 September 2024).
• Kuhn, M.; Vaughan, D.; Hvitfeldt, E. Yardstick: Tidy Characterizations of Model Performance. 2024. Available online: https://CRAN.R-project.org/package=yardstick (accessed on 15 September 2024).
• Box, G.E.P.; Jenkins, G.M.; Reinsel, G.C.; Ljung, G.M. Time Series Analysis. Forecasting and Control , 5th ed.; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2016. [ Google Scholar ]
• Hyndman, R.J.; Athanasopoulos, G. Forecasting: Principles and Practice , 3rd ed.; OTexts: Melbourne, Australia, 2021; Available online: https://otexts.com/fpp3/ (accessed on 15 September 2024).
• Patle, G.T.; Singh, D.K.; Sarangi, A.; Rai, A.; Khanna, M.; Sahoo, R.N. Time series analysis of groundwater levels and projection of future trend. J. Geol. Soc. India 2015 , 85 , 232–242. [ Google Scholar ] [ CrossRef ]
• Sen, P.K. Estimates of the Regression Coefficient Based on Kendall’s Tau. J. Am. Stat. Assoc. 1968 , 63 , 1379–1389. [ Google Scholar ]
• Kendall, M.G. Rank Correlation Methods ; Charles Griffin: London, UK, 1970. [ Google Scholar ]
• Krishnakumar, P.; Lakshumanan, C.; Kishore, V.P.; Sundararajan, M.; Santhiya, G.; Chidambaram, S. Assessment of groundwater quality in and around Vedaraniyam, South India. Env. Earth Sci. 2014 , 71 , 2211–2225. [ Google Scholar ]
• United Nations WWD. Valuing Water for the Economy. 2021–2023 [Internet]. 2023. Available online: https://www.unesco.org/reports/wwdr/2021/en/valuing-water-economy (accessed on 12 August 2024).
• Neme Castillo, O.; Valderrama Santibañez, A.L.; Chiatchoua, C. Determinants of productive water consumption and effects on economic activity in Mexico. Econ. Soc. Territ. 2021 , 21 , 505–537. [ Google Scholar ]
• Rahim, M.S.; Nguyen, K.A.; Stewart, R.A.; Giurco, D.; Blumenstein, M. Machine learning and data analytic techniques in digital water metering: A review. Water 2020 , 12 , 294. [ Google Scholar ] [ CrossRef ]
• Markanicz, J.; MMikołajczak, M. Czy świadomość na temat fast fashion ma wpływ na decyzje zakupowe konsumentów? Teor. I Prakt. Dydakt. Akademickiej. 2024 , 1 . Available online: https://czasopisma.bg.ug.edu.pl/index.php/TiPDA/article/view/10650 (accessed on 19 August 2024).
• André, F.J.; Buendía, A.; Santos-Arteaga, F.J. Efficient water use and reusing processes across Spanish regions: A circular data envelopment analysis with undesirable inputs. J. Clean. Prod. 2024 , 434 , 139929. [ Google Scholar ]

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Legarreta-González, M.A.; Meza-Herrera, C.A.; Rodríguez-Martínez, R.; Chávez-Tiznado, C.S.; Véliz-Deras, F.G. Time Series Analysis to Estimate the Volume of Drinking Water Consumption in the City of Meoqui, Chihuahua, Mexico. Water 2024 , 16 , 2634. https://doi.org/10.3390/w16182634

Legarreta-González MA, Meza-Herrera CA, Rodríguez-Martínez R, Chávez-Tiznado CS, Véliz-Deras FG. Time Series Analysis to Estimate the Volume of Drinking Water Consumption in the City of Meoqui, Chihuahua, Mexico. Water . 2024; 16(18):2634. https://doi.org/10.3390/w16182634

Legarreta-González, Martín Alfredo, César A. Meza-Herrera, Rafael Rodríguez-Martínez, Carlos Servando Chávez-Tiznado, and Francisco Gerardo Véliz-Deras. 2024. "Time Series Analysis to Estimate the Volume of Drinking Water Consumption in the City of Meoqui, Chihuahua, Mexico" Water 16, no. 18: 2634. https://doi.org/10.3390/w16182634

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Add a method, remove a method, edit datasets, disinfectant control in drinking water networks: integrating advection-dispersion-reaction models and byproduct constraints.

12 Sep 2024  ·  Salma M. Elsherif , Ahmad F. Taha , Ahmed A. Abokifa · Edit social preview

Effective disinfection is essential for maintaining water quality standards in distribution networks. Chlorination, as the most used technique, ensures safe water by maintaining sufficient chlorine residuals but also leads to the formation of disinfection byproducts (DBPs). These DBPs pose health risks, highlighting the need for chlorine injection control (CIC) by booster stations to balance safety and DBPs formation. Prior studies have followed various approaches to address this research problem. However, most of these studies overlook the changing flow conditions and their influence on the evolution of the chlorine and DBPs concentrations by integrating simplified transport-reaction models into CIC. In contrast, this paper proposes a novel CIC method that: (i) integrates multi-species dynamics, (ii) allows for a more accurate representation of the reaction dynamics of chlorine, other substances, and the resulting DBPs formation, and (iii) optimizes for the regulation of chlorine concentrations subject to EPA mandates thereby mitigating network-wide DBPs formation. The novelty of this study lies in its incorporation of time-dependent controllability analysis that captures the control coverage of each booster station. The effectiveness of the proposed CIC method is demonstrated through its application and validation via numerical case studies on different water networks with varying scales, initial conditions, and parameters.

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Narrative Review of Hydration and Selected Health Outcomes in the General Population

Deann liska.

1 Biofortis, Mérieux NutriSciences, Addison, IL 60101, USA; [email protected]

Tristin Brisbois

2 PepsiCo, Inc., Purchase, NY 10577, USA; [email protected] (T.B.); [email protected] (P.L.B.)

Pamela L. Barrios

Lindsay b. baker.

3 Gatorade Sports Science Institute, Barrington, IL 60010, USA; [email protected]

Lawrence L. Spriet

4 Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W, Canada; ac.hpleugou@teirpsl

Although adequate hydration is essential for health, little attention has been paid to the effects of hydration among the generally healthy population. This narrative review presents the state of the science on the role of hydration in health in the general population, specifically in skin health, neurological function (i.e., cognition, mood, and headache), gastrointestinal and renal functions, and body weight and composition. There is a growing body of evidence that supports the importance of adequate hydration in maintaining proper health, especially with regard to cognition, kidney stone risk, and weight management. However, the evidence is largely associative and lacks consistency, and the number of randomized trials is limited. Additionally, there are major gaps in knowledge related to health outcomes due to small variations in hydration status, the influence of sex and sex hormones, and age, especially in older adults and children.

1. Introduction

Water is essential for life and is involved in virtually all functions of the human body [ 1 ]. It is important in thermoregulation, as a solvent for biochemical reactions, for maintenance of vascular volume, and as the transport medium for providing nutrients within and removal of waste from the body [ 2 ]. Deficits in body water can compromise our health if they lead to substantial perturbations in body water balance [ 2 ]. As with other essential substances, intake recommendations for water are available from various authoritative bodies [e.g., Institute of Medicine (IOM) and European Food Safety Authority (EFSA)], and generally range from 2–2.7 L/day for adult females and 2.5–3.7 L/day for adult males [ 1 , 2 ].

Body water balance depends on the net difference between water gain and water loss. The process of maintaining water balance is described as “hydration”. “Euhydration” defines a normal and narrow fluctuation in body water content, while “hypohydration” and “hyperhydration” refer to a generalized body water deficit or excess, respectively, beyond the normal range. Finally, “dehydration” describes the process of losing body water while “rehydration” describes the process of gaining body water. Dehydration can be further classified based on the route of water loss and the amount of osmolytes (electrolytes) lost in association with the water. Iso-osmotic hypovolemia is the loss of water and osmolytes in equal proportions, which is typically caused by fluid losses induced by cold, altitude, diuretics, and secretory diarrhea. Hyperosmotic hypovolemia occurs when the loss of water is greater than that of osmolytes, and primarily results from insufficient fluid intake to offset normal daily fluid losses (e.g., loss of pure water by respiration and transcutaneous evaporation). Hyperosmotic hypovolemia is exacerbated with high sweat loss (warm weather or exercise) or osmotic diarrhea [ 3 , 4 ].

The normal daily variation of body water is <2% body mass loss (~3% of total body water); thus, hypohydration is clinically defined as ≥2% body mass deficit [ 5 ]. The kidneys can regulate plasma osmolality within a narrow limit (±2% or 280 to 290 mOsm/kg) and plasma osmolality between 295 and 300 mOsm/kg is considered mild or impending hyperosmotic hypovolemia, while values greater than 300 mOsm/kg are considered frank hyperosmotic hypovolemia [ 6 , 7 ]. For urine osmolality, values above 1000 mOsm/L are considered elevated and may be a sign of hyperosmotic hypovolemia [ 6 , 7 ]. Finally, it has generally been accepted that a first-morning void urine specific gravity (USG) of less than or equal to 1.020 represents euhydration [ 7 , 8 ].

Hydration status is assessed in a variety of ways in human studies, the most common of which are body weight changes, plasma and/or urine osmolality, and USG. The choice of hydration assessment method and its interpretation is dependent on the type of dehydration; for example, iso-osmotic hypovolemia does not increase plasma or serum osmolality and USG due to the concurrent loss of salt and water. Further complicating the assessment of hydration status are confounding factors such as age and differences in renal function, and these limitations among others have been covered in detail elsewhere [ 6 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In addition to assessing hydration status, studies investigating the effects of hydration on health often include measurements of fluid intake, which is usually conducted with dietary assessment methods such as dietary record, diet recall, or food frequency questionnaires. A full assessment of the advantages and limitations of these methods (e.g., difficulties with method validation, challenges in usage among children and the elderly with cognitive issues) are outside the scope of the current review, but have been discussed in detail by others [ 17 , 18 ].

Several reviews on the role of hydration in disease development and progression, as well as the role of hydration in exercise and physical performance have been published [ 19 , 20 , 21 , 22 , 23 ]. However, few reviews are available on the role of hydration in general health, with the exception of a few outcome areas (e.g., weight loss, cognition). An assessment of the role of hydration in general health that thoroughly evaluates the evidence related to the commonly believed benefits of hydration is not available. Thus, the objective of this review was to provide an assessment of the current state of science on hydration and health relevant to the general population. This review includes skin health, neurological, gastrointestinal and renal functions, and body weight and composition in relation to hydration in generally healthy individuals. Publications reviewed include the most current systematic reviews and meta-analyses as well as primary intervention studies published since these reviews.

2. Materials and Methods

The PubMed database was initially searched for reviews on hydration that were published in English. All searches and screening were performed independently by two authors. Reviews were identified using the search terms “hydration” and “dehydration” and selection included those that were conducted using a systematic search process and related to a health area applicable to the general population. In the absence of systematic reviews and meta-analyses, comprehensive narrative reviews that included details on the studies reviewed were included, while opinion pieces were excluded. In addition, hand-searching of references in selected reviews were performed. Key systematic and comprehensive reviews and meta-analyses are summarized in Table 1 .

Summary of key hydration reviews.

Abbreviations: AMSTART, A MeaSurement Tool to Assess systematic Reviews; CI, confidence interval; PRISMA, Preferred Reporting Items for Systematic Reviews; RCT, randomized controlled trial; RR, relative risk. 1 PRISMA is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses and has been used to assess reporting quality. For meta-analysis, the PRISMA checklist contained 24 required reporting items that were used to assess quality. For systematic reviews, 19 items remained after exclusion of items specific to meta-analyses (i.e., item 13, 14, 15, 21, and 22 which are related to data analysis and overall risk bias assessment). 2 AMSTAR 2 is an instrument used to assess the methodological quality of systematic reviews and meta-analysis. It has 16 items in total, whereby three of these are specific for meta-analysis. AMSTAR 2 is not intended to generate an overall score and thus, none is provided.

In order to represent the current state of the literature, primary studies that were not included in the reviews were also identified. Individual searches for clinical intervention trials in generally healthy populations (ages >2 years) and excluding those conducted in diseases populations were conducted in PubMed using the All Fields (ALL) function for terms for hydration and the specific health outcome area. When a systematic review had been identified, the updated search for primary literature overlapped the search in the published systematic review by a year. When a systematic review of a specific topic was not found, the search for primary literature was performed in PubMed starting from its inception. Search terms were compared with the systematic reviews on each topic, when available.

A flowchart documenting the updated search strategy and results is shown in Figure 1 . The updated search for weight management used the terms “(fluid OR water OR hydration OR dehydration) AND (weight OR BMI (body mass index) OR circumference)”. For hydration and skin, the terms included “(fluid OR water OR hydration OR dehydration) AND (skin OR epidermal OR transepidermal) NOT (topical OR injection OR injector)”. Search terms for studies on hydration and neurological function were “(water OR hydration OR dehydration) AND (mental OR mood OR cognition OR fatigue OR sleep OR headache)” and studies in diseased population such as dementia were excluded. For gastrointestinal function, the search terms included “(fluid OR water OR hydration OR dehydration) AND (intestinal OR gastric OR constipation) NOT (infant OR cancer)”. Finally, for hydration and renal function, “(fluid OR water OR hydration OR dehydration) AND (kidney OR renal) NOT (infant OR cancer)” was used and studies involving diseased populations such as chronic kidney disease were excluded. Only clinical trials that were not included in systematic reviews are reported in detail in each health outcome section. Information from each primary study was extracted using a pre-determined PICOS (population, intervention, comparison, outcome, study design) table, making sure that any reports of hydration status (e.g., body weight change, plasma osmolality) or fluid intake were recorded.

PRISMA flowchart.

Finally, the reporting and methodological qualities of each systematic review and meta-analysis was assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist ( http://www.prisma-statement.org/ ) and A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 ( https://amstar.ca/index.php ). For meta-analyses, the PRISMA checklist contained 24 required reporting items and three optional items [item 16 (description of additional analyses, if performed), item 19 (reporting of data on risk of bias for each study, if performed), and item 23 (reporting of results of additional analysis, if performed)]. Only the required items were used for scoring. For systematic reviews, 19 items remained after exclusion of optional items and items specific to meta-analyses (i.e., items 13, 14, 15, 21, and 22, which are related to data analysis and risk bias assessment). AMSTAR 2 has 16 items in total, whereby three of these are specific for meta-analysis.

3. Hydration and Health Outcomes

3.1. skin health.

The skin’s primary functions are to protect the body from external challenges (e.g., chemicals, microbiological materials, and physical stressors), regulate water loss and body temperature, and sense the external environment [ 30 , 31 , 32 ]. The skin also serves as a reservoir for nutrients and water and contributes to important metabolic activities [ 30 ]. The external layer of the skin provides an epidermal barrier, which is composed of 15–20 layers of cornified keratinocytes (corneocytes). The stratum corneum (SC) layer of the epidermis is the primary location of the barrier function; however, both the dermis and the multilayered epidermis are important for maintenance of barrier integrity [ 32 ]. Measurements for skin barrier function and hydration include transepidermal water loss (TEWL), SC hydration, “deep” skin hydration, clinical evaluation of dryness, roughness and elasticity, skin relief parameter, the average roughness, evaluation of skin surface morphology, skin smoothness and roughness, extensibility, sebum content, and skin surface pH [ 24 ].

For hydration and skin health, a 2018 systematic review was identified [ 24 ], which included five intervention studies. Of these studies, four measured surface hydration and reported increased SC hydration following additional intake of 2 L daily of water over a period of 30 days [ 33 , 34 , 35 ] or additional intake of 1 L per day for a period of 42 days [ 36 ]. Of note, only one of these studies [ 34 ] compared the effect of additional water consumption in those who habitually consumed below or above the EFSA water requirement (2 L/day). Other studies either assessed participants who were habitually meeting or exceeding the European Food Safety Authority (EFSA) requirements [ 33 , 35 ] or failed to report baseline fluid intake [ 36 , 37 ]. In studies that stratified based on baseline water intake [ 33 , 34 , 35 ], positive impact on skin hydration was evident in participants whose baseline total water intake was less than 3.2 L per day. Measurements of dryness and roughness were reported in one study [ 36 ] and these decreased with additional water intake. Measurements of skin elasticity [ 36 ], extensibility [ 33 ], and the ability of the skin to return to its original state [ 35 ] were greater with additional water intake. However, the review authors concluded that the evidence is weak in terms of quantity and methodological quality, and risk of bias in the interventional studies is extremely high [ 24 ]. With the exception of providing an explicit statement of questions being addressed and clarifying if a review protocol existed, the 2018 systematic review fulfilled all required PRISMA reporting items ( Table 1 ). The systematic review fulfilled only four out of the 13 required AMSTAR 2 items and lacked clarity on inclusion criteria and study selection, robustness of study selection, and completeness in description and assessment of included studies.

Our updated search resulted in 178 titles ( Figure 1 ), but the vast majority assessed topical applications (e.g., moisturizers), oral ingestion of supplements or herbals, or skin conditions in disease states. No new intervention studies were found when compared with the 2018 systematic review [ 24 ].

3.2. Neurological Function

Studies on hydration and neurological function focused on cognition, mood, fatigue, sleep, and headache. In general, the areas of cognition, mood, and fatigue overlap in studies, with some also including sleep and headache outcomes. No single systematic review covered these various topics; however, comprehensive narrative reviews that included discussions on cognition [ 26 ] and headache [ 19 ] were identified. Thus, our search for primary literature on this topic was not limited to recent literature ( Figure 1 ). After screening, 29 studies were selected and these are summarized in Table 2 . Of the cognition studies, eight investigated children and adolescents, 18 adults, and one both children and adults, while two other studies looked at headaches in adults. None of the intervention studies were specific to fatigue or sleep.

Intervention Studies on Hydration and Neurological Function 1 .

Abbreviations: C, Celsius; d, day; EFSA, European Food Safety Authority; F, female; g, grams; h, hours; IOM, Institute of Medicine; kg, kilogram; L, liter; M, male; min, minute; mL, milliliter; MRI, magnetic reasonance imaging; n , sample size; oz, ounces; POMS, Profile of Mood States; RCT, randomized clinical trial; Uosm, urine osmolality; VAS, Visual Analogue Scale; y, years. 1 Intervention trials published since inception through April 2018.

3.2.1. Cognition, Mood, and Fatigue in Adults

Cognition is a complex function that is composed of several subdomains including different types of memory, attentiveness, reaction time, and executive function. Studies often differ in the specific subdomains assessed as well as the tool used for these measurements. Assessments of mood are also varied across studies, with a number of different types of questionnaires; although a consensus approach does not exist, some validated questionnaires are available [e.g., Bond-Lader, Profile of Moods States (POMS)] and these are the most commonly used.

Several recent reviews of the data in adults have been published ( Table 1 ). Benton and Young [ 25 ] concluded that reductions in body mass by >2% due to dehydration are consistently associated with greater fatigue and lower alertness; however, the effects on cognition is less consistent. Masento et al. [ 26 ] summarized that severe hypohydration was shown to have detrimental effects on short-term memory and visual perceptual abilities, whereas water consumption can improve cognitive performance, particularly visual attention and mood. These authors also note some of the challenges with studying hydration effects on mood and cognition include variations among subjects (e.g., differing levels of thirst at baseline, habitual intake, and individual adaptation), mediating factors (e.g., water temperature, time of cognition testing, testing environment), variation in types of cognition tests, and distinguishing effects due to thirst and hydration status.

As noted by previous review authors, the studies we identified on attention are heterogeneous in methodology and outcomes. Studies included acute and chronic water consumption, with or without initial dehydration, and measured various types of attention including visual, sustained, and focused ( Table 2 ). Following an overnight fast, acute intake of 25, 200, or 300 mL water improved visual attention [ 50 , 38 ]. Acute intake of water (120 or 330 mL) immediately before testing improved sustained attention in one study [ 62 ], but not in another that required overnight fasting prior to consumption of 300 mL water [ 61 ]. Both studies assessed sustained attention using the Rapid Visual Information Processing task although the former allowed habitual fluid intake prior to cognition assessments (performed at 11 am or 3 pm), and the latter restricted fluid and food intake for 9 h prior to testing. When dehydration was induced by exercise with or without diuretic (body mass loss of ≥1%), sustained attention decreased compared to exercise with fluid replacement in men [ 56 ]. However, a similar dehydration and euhydration protocol did not affect sustained attention in women [ 55 ]. Dehydration induced by water deprivation (average body mass loss of 1%) also did not affect visual attention [ 47 ]. Under hot conditions (30 °C), dehydration (mean body mass loss of 0.7%) followed by water consumption improved focused attention compared to dehydration without water consumption [ 48 ]. Fluid restriction for 28 h (mean body mass loss of 2.5%) did not affect visual, sustained, and divided attention, although subjects reported needing a greater amount of effort and concentration necessary for successful task performance when dehydrated compared to euhydration [ 59 ]. Finally, in dose–response studies, attention deteriorated starting at 2% body mass loss [ 63 , 64 ].

Studies on memory are equally heterogeneous in methodology and results. Working memory has been shown to improve following acute intake of water by some [ 38 ], but not others [ 50 , 61 ]. When dehydration was induced by exercise with or without diuretic (body mass loss of ≥1%), working memory decreased compared to exercise with fluid replacement in men [ 56 ]. However, a similar dehydration and euhydration protocol did not affect working and short-term memory in women [ 55 ]. Dehydration following water deprivation (average body mass loss of 1%) increased errors for tests for visual/working memory [ 47 ]. Working memory was also unaffected by dehydration (body mass loss of 1 to 3%) induced by two weeks of low-fluid diet (≤40 oz fluid/day or ≤1.2 L/day) [ 51 ]. Additionally, more extreme hypohydration (mean body mass loss of 4%) did not affect short-term spatial memory in men [ 53 ]. Under hot conditions (30 °C), dehydration (mean body mass loss of 0.7%) followed by water consumption improved episodic memory compared to dehydration without water consumption [ 48 ]. Finally, in dose–response studies, short-term memory started deteriorating after 2% body mass loss [ 63 , 64 ].

Compared with attention and memory, fewer studies assessed reaction time. Simple reaction time was unaffected by acute consumption of 200 mL water prior to testing [ 50 ]. In another study that evaluated thirst sensation, subjects who were thirsty and provided 0.5–1 L of water had better simple reaction time compared to thirsty subjects who did not consume water [ 52 ]. Choice reaction time was unaffected by hypohydration in women (≥1% body mass loss) [ 55 ] or in men (mean body mass loss of 4%) [ 53 ]. Both simple and choice reaction time were unaffected by hypohydration in women (average body mass loss of 1%) [ 47 ].

Other lesser studied cognitive subdomains include grammatical reasoning, spatial cognition, verbal response time, and executive function. Grammatical reasoning was unaffected by hypohydration in women (≥1% body mass loss) [ 55 ] or in men (mean body mass loss of 4%) [ 53 ]. Flight performance and spatial cognition of healthy pilots were compromised by dehydration (body mass loss of 1 to 3%) induced by 2 weeks of low-fluid diet (≤40 oz fluid/day or ≤1.2 L/day) [ 51 ]. Hypohydration following 28 h of fluid restriction (mean body mass loss of 2.5%) decreased verbal response time in women, but increased verbal response time in men and did not affect cognitive-motor speed in either women or men [ 59 ]. Smaller degree of dehydration by fluid restriction (mean body mass loss of 1.08%) also did not affect motor speed and visual motor function, visual learning, and cognitive flexibility, but decreased executive function and spatial problem solving [ 47 ]. Speed, accuracy, and mental endurance were decreased after 3 h of fluid deprivation (500 g fluid/day), and decreased stability occurred after 35 h [ 58 ]. Finally, in dose–response studies, arithmetic efficiency, motor speed, and perceptual motor coordination deteriorated starting at 2% body mass loss [ 63 , 64 ].

Overall, negative emotions such as anger, hostility, confusion, depression, and tension as well as fatigue and tiredness increase with dehydration of ≥1% [ 53 , 55 , 56 , 59 , 60 ] and fluid deprivation (24 h [ 54 ]). In men, fluid deprivation (500 g (or ~500 mL) fluid for 24 h) decreased energy ratings after 15 h but did not affect depression, anxiety, and self-confidence [ 58 ]. Only one study assessed water consumption following dehydration and demonstrated decreased anxiety, but not depression, when mildly dehydrated subjects (mean body mass loss of 0.2%) were provided with water [ 48 ]. Acute water intake by subjects after an overnight fast did not affect various mood ratings [ 50 , 61 ]. Additionally, although thirsty subjects were more tired and tense, provision of 0.5–1 L water did not affect tired and tense ratings [ 52 ]. It is possible that mood effects of acute water consumption in these studies were not observed due to the timing of testing relative to water consumption (often >20 min). Indeed, acute water intake (120 and 220 mL) increased alertness assessed after 2 min, but not when assessed after 25 or 50 min of water consumption [ 62 ]. Increasing water intake of low-consumers (<1.2 L/day) decreased confusion/bewilderment scores and fatigue/inertia scores while decreasing water intake of high-consumers (>2 L/day) decreased contentedness, calmness, positive emotions, and vigor/activity scores without affecting sleepiness [ 49 ]. Finally, fluid deprivation for 24 h did not affect sleepiness [ 54 ].

In general, our assessment is consistent with the conclusions from the aforementioned reviews, whereby hypohydration and/or thirst is consistently associated with increased negative emotions. The effect of hypohydration on attention and memory seem to suggest that >1% body mass loss is associated with deterioration in attention and memory, although this may be subdomain- and/or sex-dependent. Fatigue/tiredness appears to be rated higher with dehydration and is unlikely to be affected by acute water consumption. Data on other domains of cognition and sleepiness are sparse and require further research.

3.2.2. Cognition and Mood in Children

Our search identified nine studies, which are summarized in Table 2 . Similar to data for adults, results from studies on hydration and cognition and mood in children are mixed. Studies in children have reported improvements in visual attention [ 38 , 41 , 44 , 45 , 54 ], but not sustained attention [ 46 ] following acute water consumption. The effect of acute effects of hydration on memory is dependent on the type of memory assessed, whereby some studies reported improvements in immediate memory [ 46 ] and others reporting no effects on verbal memory [ 38 ], visual memory [ 44 ], and story memory [ 45 ]. For the aforementioned acute studies, although a majority of studies did not assess baseline hydration status, it is likely that the children were mildly hypohydrated prior to acute water intake. In adolescents (mean age of 16.8 y), dehydration induced by thermal exercise (mean body mass loss of 1.7%) did not affect executive function, although brain imaging demonstrated increased fronto-parietal brain activation during the cognition task, suggesting a need for greater mental effort when dehydrated [ 43 ].

For longer-term water consumption (i.e., one whole day), results were mixed. Short-term memory assessed by auditory number span improved with additional water consumption (average 624 mL over a school day) in one study [ 42 ], but was not replicated in another study using digit recall [ 39 ], although exact amount of water consumed was not reported in the latter study. Other cognition domains including visual attention, selective attention, visual memory, visuomotor skills, perceptual speed, and verbal reasoning were unaffected by additional water consumption throughout the day [ 42 , 39 ].

Data on mood in relation to hydration status is also limited in children. Mood assessed using the POMS questionnaire did not change following additional water consumption for one day [ 42 ] while subjective ratings on happiness were not significantly affected by acute water consumption [ 45 ].

Overall, acute consumption of fluid by children appears to improve visual attention, with data on sustained attention being mixed. The effect of acute and chronic fluid consumption on memory is sparse and inconsistent. Finally, the limited data available on hydration and children suggest that hydration does not affect mood.

3.2.3. Headache

Hypohydration is thought to be a cause of headache, and increased fluid consumption has been suggested to relieve some forms of headache. However, evidence on hydration and headache is limited. The two intervention trials that were conducted by the same group were identified, with the earlier report describing a pilot assessment for the latter report, which was a larger trial [ 65 , 66 ]. Results from the two-week pilot study on migraines in adults were promising, with observed reductions in total hours of headache and mean headache intensity in the subjects who drank additional 1.5 L/day water compared to a control group who were given a placebo tablet [ 66 ]. In the follow-up study, a larger intervention trial, drinking more water (additional 1.5 L/day) resulted in a statistically significant improvement of 4.5 points on the Migraine-Specific Quality of Life scale [ 65 ]. Almost half (47%) of the subjects in the intervention (water) group self-reported improvement against 25% of the subjects in the control group [ 65 ]. However, objective measures such as headache days, hours of headache, and medication use were not different between subjects who consumed additional water and controls [ 65 ]. The authors noted several limitations in the larger intervention study, including partial unblinding of subjects, small sample size, and a large attrition rate [ 65 ].

3.3. Renal Function

A common disorder discussed in reviews found on hydration and kidney/renal function is kidney stones, which affects up to 12% of the world population [ 67 ]. Observational studies report an association between low total fluid intake and high risk for kidney stones, leading to guidelines recommending increasing fluid intake as a preventative strategy against kidney stones [ 68 , 69 ]. Although our search strategy was not designed to target any specific renal condition, only studies on kidney stones remained after filtering out diseases/disorders that are not relevant to the general population (e.g., chronic kidney disease). We identified one meta-analysis on high fluid intake and kidney stones which reported a significant association between high fluid intake and a lower risk of incident kidney stones, with 0.40-fold (RCTs) and 0.59-fold (observational studies) decreased risk [ 27 ]. In addition, high fluid intake reduced the risk of recurrent kidney stones (RR 0.40) [ 27 ]. With the exception of providing an explicit statement of questions being addressed and clarifying if a review protocol existed, the meta-analysis fulfilled all required PRISMA reporting items ( Table 1 ). The meta-analysis fulfilled 10 out of the 16 required AMSTAR 2 items, but lacked clarity on study selection and completeness in assessment of included studies.

There have been very few intervention studies measuring the effect of hydration on kidney stones. We identified two relevant studies and these were already included in the aforementioned 2016 meta-analysis. In a 5-year randomized study, patients with idiopathic calcium stone disease had a 12% recurrence rate when encouraged to increase their fluid intake to achieve a urine output of 2 L/day, and a 27% recurrence rate if they were not given specific advice on urine output [ 70 ]. Another study investigated the effects of increased fluid intake (to achieve urine output of at least 2.5 L/day) following shock wave lithotripsy (SWL) treatment in stone patients. Among those who were stone free following SWL treatment, rate of recurrence was 8.3% for those with increased fluid intake, compared to 40% for those who were taking Verapamil, a calcium entry blocking agent, and 55% for those who were not provided any specific medication or dietary instructions [ 71 ]. Although not statistically significant, the rate of stone regrowth among those with residual fragments following SWL was lowest in subjects with increased fluid intake compared to those who received Verapamil (15.3% vs. 20%, respectively) [ 71 ]. Subjects who did not receive any intervention had a regrowth rate of 64% [ 71 ].

3.4. Gastrointestinal Function

Our search on hydration and gastrointestinal function resulted in one review that addressed the role of fluid intake in the prevention and treatment of functional intestinal constipation in children and adolescents [ 28 ] ( Table 1 ). One review was found on the effect of beverage types on gastric emptying and subsequent nutrient absorption [ 72 ]; however, this is outside the scope of our review as it did not address hydration alone. Following screening, we found four intervention studies on constipation and one study that assessed the effect of dehydration on gastrointestinal function at rest in humans ( Table 3 ). Our search strategy also resulted in a number of intervention studies that compared different types of beverages on exercise-induced gastrointestinal dysfunction and dehydration, and as noted in the methods, these were not considered within scope of the present review.

Intervention Studies on Hydration and Gastrointestinal Function 1 .

Abbreviations: d, day; F, female; g, grams; L, liter; M, male; min, minute; mL, milliliter; n , sample size; RCT, randomized clinical trial; SD, standard deviation; y, years. 1 Intervention trials published since inception through April 2018.

The review on functional intestinal constipation in children and adolescents included 11 studies that either evaluated fluid intake as a risk factor for constipation or evaluated the role of fluid intake in the treatment of intestinal constipation in children or adolescents [ 28 ]. Authors reported the possibility of a causal association between lower fluid intake and constipation but noted that study outcomes were heterogeneous and thus, difficult to compare [ 28 ]. For the most part, studies that assessed fluid intake as a treatment of constipation showed no effects, although authors again noted the heterogeneity in methodologies of the studies [ 28 ]. Of the four intervention studies on constipation, two reported beneficial effects of increased fluid intake on stool measurements and the other two reported no effects ( Table 3 ). The largest trial involved 117 adults with chronic functional constipation randomized to receive 25 g/day fiber alone (with ad libitum fluid intake) or 25 g/day fiber alone with 2 L/day water for 2 months [ 73 ]. The water supplemented group consumed more fluid (mean of 2.1 L/day vs. mean of 1.1 L/day) and had greater stool frequency and fewer use of laxatives compared to the ad libitum group [ 73 ]. In another study, healthy men were prescribed standardized nutritional and physical activity regimens and randomized to 0.5 L or 2.5 L of fluid per day for one week followed by a crossover after a two-week washout period [ 74 ]. During periods of fluid restriction, authors observed reduction in stool weight and frequency and increased tendency towards constipation [ 74 ]. When regular fluid consumption was resumed, bowel function returned to normal [ 74 ]. In contrast, the two other intervention studies in adults did not report changes in stool measurements following additional fluid intake. Consumption of additional 1 L/day for the first two days followed by 2 L/day for the next two days of either near isotonic fluid or hypotonic fluid (i.e., water) increased urinary output but did not affect stool weight in healthy adults [ 75 ]. Addition of 15 g/day wheat bran for 14 days slowed gastric emptying, shortened oroanal transit, and increased stool frequency and stool weight; however, the consumption of 600 mL fluid with the wheat bran did not affect these measurements when compared to consumption of wheat bran alone [ 76 ].

Finally, heat-induced dehydration of 3% body mass loss decreased gastric emptying compared to euhydration conditions, but did not affect orocecal transit time, intestinal permeability, and intestinal glucose absorption in healthy men ( n = 10) [ 77 ].

3.5. Body Weight and Body Composition

Studies on beverage consumption and weight management have mainly focused on the replacement of caloric beverages with non-caloric or lower calorie beverages. A 2016 systematic review on water intake and body weight/weight management was identified [ 29 ], which provides a comprehensive listing of the human intervention studies published through 2014 that assessed water intake on energy intake, energy expenditure, body mass index (BMI), and weight change. The review included 134 total RCTs representing 440 different test conditions. Only a handful of these studies investigated the effects of water intake on body weight and body composition independent of changes in caloric intake and physical activity. Two were studies in adults [ 78 , 79 ] and two were in children [ 80 , 81 ]. Akers et al. [ 78 ] reported reductions in body fat, but not body weight or BMI, in overweight and obese adults who consumed ~3 times more water compared to a control group (average 1241 g/day vs. 451 g/day, respectively). In this study, energy intake of the water group was slightly greater than that of the control group, although these were not significantly different (average 1726 kcal/day vs. 1654 kcal/day).In another study, adults who were assigned a hypocaloric diet and 500 mL water prior to each daily meal lost more body weight and total fat mass compared to those on a hypocaloric diet alone [ 79 ]. Energy intake significantly decreased by the end of the 12-week intervention but was not different between water and control groups (average intake at 12 weeks: 1454 kcal/day vs. 1511 kcal/day, respectively) [ 79 ]. Additionally, ad libitum meal intake assessed at the end of the intervention was not different between groups, with or without 500 mL water pre-load [ 79 ]. In an 8-week intervention study, children (BMI percentile of ≥ 85%) who replaced caloric beverages with water and increased water consumption lost more body weight compared to children who only replaced caloric beverages with water [ 81 ]. Of note, at the end of the study, urine osmolality was below 500 mmol/kg in the group that increased water consumption, while urine osmolality stayed above 500 mmol/kg in the group that only replaced caloric beverages with water [ 81 ]. Increased water consumption (+1 glass/day) following a water intake promotion program for 1 year did not result in changes in BMI-z scores in students, although the percentage of students who were overweight was lower in the intervention group compared to the control group [ 80 ].

Our updated search resulted in 549 titles ( Figure 1 ), and the majority of these were excluded because they investigated the effect of replacement of caloric beverages with non-caloric beverages, replacement of non-caloric beverages with water, or methodological considerations of hydration on BMI assessments. When compared with the 2016 systematic review [ 29 ], our search found four new publications; of which one [ 82 ] was a duplicate publication of a study that was already included in a previous systematic review [ 83 ]. The three new studies ( Table 4 ) varied in design, with one being a study on hydration status and energy intake [ 84 ], one on water preloading and weight loss [ 85 ], and the other on increased water consumption and weight loss [ 86 ]. Of the new studies, one investigated the very short-term effect (i.e., 24 h) of euhydration vs. hypohydration on ad libitum breakfast energy intake in healthy men and observed no difference in energy intake between groups [ 84 ]. Another reported greater weight loss following water pre-loading (500 mL) before main meals for 12 weeks in obese adults ( n = 84, [ 85 ]). Finally, increasing water consumption (mean increase of ~310 mL/day) did not affect BMI and other anthropometric measures in overweight and obese adolescents ( n = 38) who were enrolled in a weight-loss program for 6 months [ 86 ]. The results of these new studies were mostly consistent with the general observations presented by the 2016 systematic review. The long-term study that reported weight loss instructed obese subjects to follow an energy-restricted diet and consume >1 L water/day, although the change in glucose and insulin is unknown [ 85 ]. In contrast, the authors of the long-term study that did not observe changes in body weight commented that subjects failed to increase water consumption, such that there were no differences in urine specific gravity between the water and control groups [ 86 ].

Intervention Studies on Hydration and Weight Management 1 .

Abbreviations: BMI, body mass index; d, day; F, female; h, hours; kg, kilograms; M, male; mL, milliliter; n , sample size; RCT, randomized clinical trial; y, years. 1 Intervention trials published since January 2014 through April 2018; studies included in the 2018 Stookey review were not included in this table.

4. Discussion

Water is involved in virtually all bodily function. Thus, ensuring that the body has enough water to maintain proper function is important for health. According to the analysis of combined urine osmolality data from the NHANES 2009–2010 and 2011–2012 surveys, about 1/3 (32.6%) of adults (ages 18–64 years old) [ 87 ] and more than half (54.5%) of children and adolescents (ages 6–19 years old) [ 88 ] in the US are inadequately hydrated. Therefore, it is important to understand the effect of hydration on health in the general population. This review is a compilation of evidence on hydration and various health outcomes thought to have a beneficial effect among the general population, including skin health, gastrointestinal and renal function, cognition, mood, headache, and body weight and composition, with cognition being the most researched. Overall, there is a growing body of evidence supporting the importance of maintaining a normal state of hydration on various health aspects, although the strength and quality of the evidence vary within each health area ( Table 5 ).

Summary of Literature Findings.

Evidence on hydration status and skin health is limited and no new studies published after a 2018 systematic review of the topic [ 24 ] were identified. Results from the handful of studies included in the review suggest that increasing water consumption may improve SC hydration. One of the most important functions of the skin is its ability to serve as an efficient barrier to molecular diffusion and the SC layer of the epidermis is the primary location of this barrier function. SC hydration is intimately related to the structure and function of the SC [ 89 ], thus, it is often an outcome in studies on skin health. The improvements in SC hydration following increased water consumption reported by existing intervention studies suggest better skin barrier function with increased oral hydration; however, these studies reported no changes in TEWL, which is another measure of skin barrier integrity. Therefore, the effectiveness of additional water consumption on skin barrier function is unclear. Furthermore, these studies failed to consistently assess other skin parameters such as those related to elasticity, firmness, roughness, surface texture, and pigmentation. Also, the applicability of the results of these studies is unclear; in most cases, subjects were already meeting the water intake recommendations and/or were required to consume water above the recommended intakes. Available studies were assessed to have low methodological quality and extremely high risk of bias by the authors of the systematic review [ 24 ].

Studies on hydration and neurological function focused on cognition, mood, and headache, with some also assessing sleep and fatigue. Studies on cognition investigated a variety of subdomains using different assessment tools, which makes comparisons across studies challenging. Evidence within each subdomain is sparse; thus, the specific influence of hydration on cognition is unclear. Reviewing the evidence in adults and children together, however, suggests that hypohydration negatively influences attention and results in the need for greater effort when performing attention-oriented tasks, which is ameliorated by rehydration. The effects of hypohydration and rehydration are less pronounced for memory and reaction time. Our observations are consistent with results from a recent meta-analysis published after our search date of April 2018 [ 90 ]. The meta-analysis authors reported that high-order cognitive processing (involving attention and executive function) and motor coordination appear more susceptible to impairment following dehydration compared to other domains involving lower order mental processing (e.g., simple reaction time) [ 90 ]. Additionally, across all cognitive domains and outcomes, studies eliciting a >2% body mass loss resulted in significantly greater cognitive impairments than studies eliciting ≤ 2% body mass loss [ 90 ]. The relationship between hydration and mood appears to be more consistent in adults, with hypohydration associated with increased negative emotions such as anger, hostility, confusion, depression, and tension as well as fatigue and tiredness. In children, however, data on hydration and mood is very limited and unclear. Overall, hydration does affect cognition and mood, although the specifics of the relationships are unclear. Finally, the evidence is too limited to determine if hydration affects headache. Two studies reported that increases in water consumption did not improve objective measures of headache, including number of days with headaches, hours of headache, and medication use, although subjective measures, such as headache intensity rating and quality of life questionnaire scores, were improved.

The renal system plays an important role in maintaining water and salt homeostasis; thus hydration is often associated with renal function and health, particularly the risk of kidney stones. The pathophysiology of kidney stone development is not yet fully understood, although a likely cause is an acquired or congenital anatomical structural abnormality [ 91 ]. Kidney stones form when the concentration of stone-forming salts exceeds their saturation point in the urine [ 91 ]. Thus, it is commonly suggested that dehydration may lead to the development of kidney stones, and that consumption of fluid may decrease the risk of kidney stones. Findings consistently suggest that increased fluid intake resulting in increased urine output is related to reduced risk of kidney stone development or recurrence rate, although data are limited. For example, a recent meta-analysis that included two intervention and seven observational studies reported a significant association between high fluid intake and a lower risk of incident kidney stones [ 27 ]. The observational studies were of moderately high quality, however, the two intervention studies were of low quality [ 27 ]. Further, limitations in the current literature include differences in diagnostic methodology of kidney stones, as well as inconsistent definitions of stone occurrence and recurrence. Overall, kidney stone occurrence is likely dependent on hydration and additional intervention studies are needed to confirm this relationship.

Another important kidney function is the removal of a wide variety of potentially toxic xenobiotics, xenobiotic metabolites, as well as metabolic wastes from the body. Elimination of unwanted substances via the urine depends on several variables that are, in turn, highly dependent on hydration status. These include renal blood flow, the glomerular filtration rate, the capacity of the kidney to reabsorb or to secrete drug molecules across the tubular epithelium, urine flow, and urine pH [ 92 ]. Because of this, detoxification is commonly associated with fluid intake or hydration. In conventional medicine, toxins generally refer to drugs and alcohol, and ‘detox’ is the process of weaning patients off these addictive substances. Commercially (and among laypersons), “detox” often refers to the removal of substances that may include, but are not limited to pollutants, synthetic chemicals, heavy metals, and other potentially harmful products of modern life. Little, if any, evidence exists to support the use of commercial detox diets for toxin elimination [ 93 ].

Increased fiber and fluid consumption are typical dietary-based therapeutic approaches to functional constipation [ 94 , 95 ]. Results from epidemiological studies suggest a possible relationship between low fluid intake and intestinal constipation occurrence. However, clinical trials currently do not support the use of increased fluid intake in the treatment of functional constipation. A comprehensive review of hydration and constipation in children and adolescents reported that fluid intake was ineffective in treating constipation [ 28 ]. Of the intervention studies we identified, one was in adults with chronic constipation and the rest were in healthy adults. Increased water intake by adults with chronic constipation increased stool frequency and decreased laxative use, while additional water consumption by healthy adults did not affect stool outcomes, suggesting a possible effect of increased hydration and improvements in stool output only in those with existing constipation. Further studies are necessary to better understand the role of water and fluids in the etiology and treatment of intestinal constipation, and study designs should include standardized evaluation tools for constipation outcomes (e.g., stool consistency, frequency of bowel movement), control for confounding dietary and lifestyle factors (e.g., fiber intake, physical activity), and measurements of hydration status and fluid intake. Additionally, published studies investigating the effect of hydration on normal functions of the gastrointestinal tract in healthy humans are lacking. Studies on dehydration and gastrointestinal function have mainly focused on exercise or gastrointestinal disorders [ 77 ].

A majority of the studies on fluid intake and weight management focused on the replacement of caloric beverages with non-caloric beverages and this has consistently resulted in lower overall energy intake [ 29 ]. However, consumption of hypoosmotic solutions such as water may contribute to weight loss by increasing lipolysis, fat oxidation, and thermogenesis, independent of changes in caloric intake as suggested by animal studies [ 96 ]. Only a handful of studies have investigated the influence of fluid intake (specifically water intake) on changes in body weight and/or body composition, independent of changes in energy intake. Existing data in adults suggest that increased water intake contributes to reductions in body fat and/or weight loss in obese adults, with or without a hypocaloric diet. Data in children/adolescents are less clear, possibly due to the smaller difference in water consumption between control and intervention groups in these studies (~350 mL/day) compared to the studies in adults (>800 mL/day). Adherence to the hydration regimen is a common problem reported by intervention studies in children/adolescents. Additionally, background diets were not collected in these studies, with the authors citing limitations in collecting dietary records in children/adolescent as the reason. While existing evidence show promising results for hydration and weight management, more studies are needed to confirm and clarify the effect of water intake on body weight and composition in adults and children.

Overall, assessing the totality of the hydration evidence is challenging due to the diversity in population, interventions, and trial designs across the studies. While many studies were conducted using a dehydration-rehydration design, variations in dehydration protocols (e.g., passive or active dehydration, type of exercise and environment, length of passive dehydration, extent of dehydration) and rehydration strategies (e.g., amount and timing of fluid intake) were observed. Outcome assessment tools, particularly for cognition, varied greatly, making it difficult to obtain enough evidence to clearly determine the impact of hydration on specific cognition subdomains. One of the biggest challenges with hydration studies is achieving consistency in the way hydration, dehydration, and overhydration is defined and measured. This is further complicated by the current lack of widely accepted screening tools or gold standard tests that allow for easily performable and replicable measurements of fluid balance and fluid intake. Another challenge for hydration studies is the difficulty in blinding subjects to the intervention. Possible solutions include providing intravenous fluid instead of oral hydration, although this bypasses the body’s normal indicators of hydration status such as thirst and oropharyngeal reflexes, which may play a role in the effect of hydration on various outcomes. Therefore, it is even more important that future studies ensure blinded assessment of study outcomes.

An important gap in knowledge is the effect of small variations in hydration on health in the general population. The point at which dehydration (or rehydration) affects health indicators is not easily determined from the current body of literature. Understanding the effect of different levels of mild dehydration on health is important as a substantial number of the general US population, especially older adults, drink less than the Adequate Intake for water that was established by the IOM [ 87 , 88 , 97 ]. Another gap in knowledge is the influence of sex on the effects of hydration on health as only a minority of the studies found considered both males and females. Additionally, there is also a need to consider the stage of the menstrual cycle as female sex hormones (estrogen and progesterone) are known to influence body fluid regulation [ 98 , 99 ]. These are particularly important considerations for studies in which outcomes are also known to be influenced by hormones, such as cognition and mood. Finally, understanding how hydration affects health in older adults and children is also important. Many of the health outcomes discussed in this review such as weight loss, cognition, kidney stones, and constipation are highly relevant to older adults and children. Older adults are susceptible to dehydration [ 100 ] due to various physiological (blunted thirst response, decline in kidney function) and environmental (limited mobility, inadequate assistance in nursing homes or hospital stays) factors [ 14 ], which can then lead to increased morbidity [ 101 , 102 ]. Meanwhile, as reviewed here, dehydration in children may have a negative impact on cognitive development and school performance in addition to physical health.

The goal of this narrative review was to present the state of the science on hydration that is relevant to the general population. Although a systematic approach was used to identify the literature and the search was broad, the publications included may not represent all available studies and reviews on the effects of hydration and specific health areas, given only one database was used, non-English publications were excluded, and the possibility that the search terms did not reflect all relevant conditions. Finally, the studies were quite heterogeneous, making broad conclusions difficult.

5. Conclusions

Water is the largest single constituent of the human body, making up approximately 60% and 75% of the adult and child human bodies, respectively. Body water deficits challenge the ability to maintain homeostasis during perturbations (e.g., sickness, physical exercise, and environmental exposure) and can affect function and health. As shown in this review, hydration status is an important aspect for health maintenance; however, evidence on the specific effects of hydration relevant to the generally healthy population is scarce and mostly inconsistent. The relationships between hydration and cognition, kidney stone risk, and weight management in generally healthy individuals are perhaps the most promising, although additional research is needed to confirm and clarify existing findings. Additional high-quality studies are needed to fill current gaps in knowledge and enable us to understand the specifics on the role of hydration in promoting health, as well as to help inform public health recommendations.

Acknowledgments

The authors would like to thank Deena Wang for assistance with the literature search and screening.

Author Contributions

Conceptualization, D.L., T.B.; systematic search, screening, and data extraction, D.L., E.M.; original draft preparation, D.L., E.M.; review and editing, D.L., E.M., L.B.B., P.L.B., T.B., L.L.S.; approval of final version, D.L., E.M., L.B.B., P.L.B., T.B., L.L.S.

Eunice Mah and DeAnn Liska received funding from PepsiCo to conduct the literature review.

Conflicts of Interest

Authors Tristin Brisbois, Pamela L. Barrios, and Lindsay B. Baker are employed by PepsiCo, Inc. The views expressed in this work are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc.

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Recycled Water for Drinking: An Overview

• Recycled water (also called reused or reclaimed water) is water that has already been used—for example from sinks or showers—and then is cleaned (treated) so it can be reused for other purposes, such as for drinking.
• No matter how dirty water starts out, it can be treated to make it safe to drink.
• Water utilities must make sure recycled water meant for drinking meets safe drinking water standards.

Water that has already been used can be treated and reused for a variety of purposes—for example, for drinking, watering plants, or firefighting.

Communities are using recycled water to better prepare for local climate change impacts, such as water shortages and floods. For example, recycled water can be a steady source of water during droughts.

How recycled water is treated will depend on the initial quality of the original source water and how the water will be used. In the United States, water utilities must treat tap water to meet federal safe drinking water standards no matter the source.

All water has been used before‎

How it works: treating recycled water for drinking, recycled water is purified during several treatment steps to make it safe to drink:.

• A wastewater treatment plant removes trash, many harmful germs, and solids from the water.
• Next, an advanced water treatment plant removes additional germs and harmful chemicals.
• Then, a drinking water treatment plant treats and disinfects the water.
• Finally, the treatment plant staff tests the water to make sure it meets federal and state drinking water standards before they pipe it to homes and businesses.

Recycled water must meet water quality standards

Recycled water that is used for drinking must meet the same water quality standards as drinking water from any other source. For example, recycled water must meet existing federal regulations for limits of germs and chemicals in drinking water.

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• Published: 11 April 2022

Water quality assessment and evaluation of human health risk of drinking water from source to point of use at Thulamela municipality, Limpopo Province

• N. Luvhimbi 1 ,
• T. G. Tshitangano 1 ,
• J. T. Mabunda 1 ,
• F. C. Olaniyi 1 &
• J. N. Edokpayi 2  

Scientific Reports volume  12 , Article number:  6059 ( 2022 ) Cite this article

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• Environmental sciences
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Water quality has been linked to health outcomes across the world. This study evaluated the physico-chemical and bacteriological quality of drinking water supplied by the municipality from source to the point of use at Thulamela municipality, Limpopo Province, South Africa; assessed the community practices regarding collection and storage of water and determined the human health risks associated with consumption of the water. Assessment of water quality was carried out on 114 samples. Questionnaires were used to determine the community’s practices of water transportation from source to the point-of-use and storage activities. Many of the households reported constant water supply interruptions and the majority (92.2%) do not treat their water before use. While E. coli and total coliform were not detected in the water samples at source (dam), most of the samples from the street taps and at the point of use (household storage containers) were found to be contaminated with high levels of E. coli and total coliform. The levels of E. coli and total coliform detected during the wet season were higher than the levels detected during the dry season. Trace metals’ levels in the drinking water samples were within permissible range of both the South African National Standards and World Health Organisation. The calculated non-carcinogenic effects using hazard quotient toxicity potential and cumulative hazard index of drinking water through ingestion and dermal pathways were less than unity, implying that consumption of the water could pose no significant non-carcinogenic health risk. Intermittent interruption in municipal water supply and certain water transportation and storage practices by community members increase the risk of water contamination. We recommend a more consistent supply of treated municipal water in Limpopo province and training of residents on hygienic practices of transportation and storage of drinking water from the source to the point of use.

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Introduction.

Water is among the major essential resources for the sustenance of humans, agriculture and industry. Social and economic progress are based and sustained upon this pre-eminent resource 1 . Availability and easy access to safe and quality water is a fundamental human right 2 and availability of clean water and sanitation for all has been listed as one of the goals to be achieved by the year 2030 for sustainable development by the United Nations General Assembly (UNGA) 3 .

The physical, chemical, biological and aesthetic properties of water are the parameters used to describe its quality and determine its capability for a variety of uses including the protection of human health and the aquatic ecosystem. Most of these properties are influenced by constituents that are either dissolved or suspended in water and water quality can be influenced by both natural processes and human activities 4 , 5 . The capacity of a population to safeguard sustainable access to adequate quantities and acceptable quality of water for sustaining livelihoods of human well-being and socioeconomic growth; as well as ensuring protection against pollution and water related disasters; and for conserving ecosystems in a climate of peace and political balance is regarded to as water security 6 .

Although the world’s multitudes have access to water, in numerous places, the available water is seldom safe for human drinking and not obtainable in sufficient quantities to meet basic health needs 7 . The World Health Organization (WHO) estimated that about 1.1 billion people globally drink unsafe water and most diarrheal diseases in the world (88%) is attributed to unsafe water, poor sanitation and unhygienic practices. In addition, the water supply sector is facing enormous challenges due to climate change, global warming and urbanization. Insufficient quantity and poor quality of water have serious impact on sustainable development, especially in developing countries 8 .

The quality of water supplied by the municipality is to be measured against the national standards for drinking water developed by the federal governments and other relevant bodies 9 . These standards considered some attributes to be of primary importance to the quality of drinking water, while others are considered to be of secondary importance. Generally, the guidelines for drinking water quality recommend that faecal indicator bacteria (FIB), especially Escherichia coli ( E. coli ) or thermo tolerant coliform (TTC), should not be found in any 100 mL of drinking water sample 8 .

Despite the availability of these standards and guidelines, numerous WHO and United Nations International Children Emergency Fund (UNICEF) reports have documented faecal contamination of drinking water sources, including enhanced sources of drinking water like the pipe water, especially in low-income countries 10 . Water-related diseases remain the primary cause of a high mortality rate for children under the age of five years worldwide. These problems are specifically seen in rural areas of developing countries. In addition, emerging contaminants and disinfection by-products have been associated with chronic health problems for people in both developed and developing countries 11 . Efforts by governmental and non-governmental organizations to ensure water security and safety in recent years have failed in many areas due to a lack of sustainability of water supply infrastructures 12 .

Water quality, especially regarding the microbiological content, can be compromised during collection, transport, and home storage. Possible sources of drinking water contamination are open field defecation, animal wastes, economic activities (agricultural, industrial and businesses), wastes from residential areas as well as flooding. Any water source, especially is vulnerable to such contamination 13 . Thus, access to a safe source alone does not ensure the quality of water that is consumed, and a good water source alone does not automatically translate to full health benefits in the absence of improved water storage and sanitation 14 . In developing countries, it has been observed that drinking-water frequently becomes re-contaminated following its collection and during storage in homes 15 .

Previous studies in developing countries have identified a progressive contamination of drinking water samples with E. coli and total coliforms from source to the point of use in the households, especially as a result of using dirty containers for collection and storage processes 16 , 17 , 18 . Also, the type of water treatment method employed at household levels, the type of container used to store drinking water, the number of days of water storage, inadequate knowledge and a lack of personal and domestic hygiene have all been linked with levels of water contamination in households 19 , 20 .

In South Africa, many communities have access to treated water supplied by the government. However, the water is more likely to be piped into individual households in the urban than rural areas. In many rural communities, the water is provided through the street taps and residents have to collect from those taps and transport the water to their households. Also, water supply interruptions are frequently experienced in rural communities, hence, the need for long-term water storage. A previous study of water quality in South Africa reported better quality of water at source than the water samples obtained from the household storage containers, showing that water could be contaminated in the process of transporting it from source to the point of use 21 .

This study was conducted in a rural community at Thulamela Municipality, Limpopo province, South Africa, to describe the community’s drinking water handling practices from source to the point of use in the households and evaluate the quality of the water from source (the reservoir), main distribution systems (street taps), yard connections (household taps) and at the point of use (household storage containers). Water quality assessment was done by assessing the microbial contamination and trace metal concentrations, and the possible health risks due to exposure of humans to the harmful pathogens and trace metals in the drinking water were determined.

The study was conducted at Lufule village in Thulamela municipality, Limpopo Province, South Africa. The municipality is situated in the eastern subtropical region of the province. The province is generally hot and humid and it receives much of its rainfall during summer (October–March) 22 . Lufule village is made up of 386 households and a total population of 1, 617 residents 23 . The study area includes Nandoni Dam (main reservoir) which acquires its raw water from Luvuvhu river that flows through Mutoti and Ha-Budeli villages just a few kilometers away from Thohoyandou town. Nandoni dam is where purification process takes place to ensure that the water meets the standards set for drinking water. This dam is the main source of water around the municipality, and it is the one which supplies water to selected areas around the dam, including Lufule village. Water samples for analysis were collected from the dam (D), street taps (ST), household taps (HT) and household storage containers (HSC) (Fig.  1 ).

Map of the study area showing water samples’ collection areas.

Research design

This study adopted a quantitative design comprising of field survey and water analysis.

Field survey

The survey was done to identify the selected households and their shared source of drinking water (street taps). The village was divided into 10 quadrants for sampling purposes. From each quadrant, 6 households were randomly selected where questionnaires were distributed and household water samples were also collected for analysis.

Quantitative data collection

A structured interviewer-administered questionnaire was employed for data collection in the selected households. The population of Lufule village residents aged 15–69 years is 1, 026 (Census, 2011). About 10% of the adult population (~ 103) was selected to complete the questionnaires to represent the entire population. However, a total of 120 questionnaires were distributed, to take care of those which might be lacking vital information and therefore would not qualify to be analysed. Adults between the ages of 18 and 69 years were randomly selected to complete the questionnaire which includes questions concerning demographic and socio-economic statuses of the respondents, water use practices, sanitation, hygiene practices as well as perception of water quality and health. The face validity of the instrument was ensured by experts in the Department of Public Health, University of Venda, who reviewed questionnaire and confirmed that the items measure the concepts of interest relevant to the study 24 . Respondents were given time to go through the questionnaire and the researcher was present to clear any misunderstanding that may arise.

Water sampling

Permission to collect water samples from the reservoir tank at the Nandoni water treatment plant and households was obtained from the plant manager and the households’ heads respectively. Two sampling sites were identified at the dam, from where a water sample each was collected during the dry and the wet season. Similarly, 8 sampling sites were identified from the street and household taps, while 60 sampling sites were targeted for the household storage containers. However, only 39 household sites were accessible for sample collection, due to unavailability of the residents at the times of the researcher’s visit. Thus, water samples were collected from a total of 57 sites. Samples were collected from each of the sites during the dry (12th–20th April, 2019) and wet seasons (9th–12th December, 2019) between the hours of 08h00 and 14h30. A total of 114 samples were collected during the sampling period: 4 from the reservoir, 16 from street taps, 16 from household taps and 78 from households’ storage systems. Water samples were collected in 500 mL sterile polyethylene bottles. After collection, the containers were transported to the laboratory on ice in a cooler box. Each of the samples was tested for physico-chemical parameters, microbial parameters and trace metals’ concentration.

Physicochemical parameters’ analysis

Onsite analysis of temperature, pH, Electrical conductivity (EC) and Total Dissolved Solids (TDS) were performed immediately after sampling using a multimeter (model HI “HANNA” instruments), following the standards protocols and methods of American Public Health Association (APHA) 25 . The instrument was calibrated in accordance with the manufacturer’s guideline before taking the measurements. The value of each sample was taken after submerging the probe in the water and held for a couple of minutes to achieve a reliable reading. After measurement of each sample, the probe was rinsed with de-ionized water to avoid cross contamination among different samples.

ICP-OES and ICP-MS analyses of major and trace elements

An inductively coupled plasma optical emission spectrophotometer (ICP-OES) was used to analyse the major metals (Calcium (Ca), Sodium (Na), Potassium (K) and Magnesium (Mg)) in the water samples while inductively coupled plasma mass spectrophotometer (ICP-MS) was used to analyze the trace metals. The instrument was standardized with a multi-element calibration standard IV for ICP for Copper (Cu), Manganese (Mn), Iron (Fe), Chromium (Cr), Cadmium (Cd), Arsenic (As), Nickel (Ni), Zinc (Zn), Lead (Pb) and Cobalt (Co) and analytical precision was checked by frequently analysing the standards as well as blanks. ICP multi Standard solution of 1000 ppm for K, Ca, Mg and Na was prepared with NH 4 OAC for analysis to verify the accuracy of the calibration of the instrument and quantification of selected metals before sample analysis, as well as throughout the analysis to monitor drift.

Microbiological water quality analysis

Analysis of microbial parameters was conducted within 6 h of collection as recommended by APHA 25 . Viable Total coliform and E. coli were quantified in each sample using the IDEXX technique approved by the United States Environmental Protection Agency (USEPA). Colilert media was added to 100 mL sample and mixed until dissolved completely. The solution was poured into an IDEXX Quanti-Tray/2000 and sealed using the Quanti-Tray sealer 26 . The samples were incubated at 35 °C for 24 h. Trays were scanned using a fluorescent UV lamp to count fluorescent wells positive for E. coli concentration and counted with the most probable number (MPN) table provided by the manufacturer 27 .

Health risk assessment

Risk assessment have been estimated for ingestion and dermal pathways. Exposure pathway to water for ingestion and dermal routes are calculated using Eqs. ( 1 ) and ( 2 ) below:

where Exp ing : exposure dose through ingestion of water (mg/kg/day); BW: average body weight (70 kg for adults; 15 kg for children); Exp derm : exposure dose through dermal absorption (mg/kg/day); C water : average concentration of the estimated metals in water (μg/L); IR: ingestion rate in this study (2.0 L/day for adults; 1.0 L/day for children); ED: exposure duration (70 years for adults; and 6 years for children);AT: averaging time (25,550 days for an adult; 2190 days for a child); EF: exposure frequency (365 days/year) SA: exposed skin area (18.000 cm 2 for adults; 6600 cm 2 for children); K p : dermal permeability coefficient in water, (cm/h), 0.001 for Cu, Mn, Fe and Cd, while 0.0006 for Zn; 0.002 for Cr and 0.004 for Pb; ET: exposure time (0.58 h/ day for adults; 1 h/day for children) and CF: unit conversion factor (0.001 L/cm 3 ) 28 .

The hazard quotient (HQ) of non-carcinogenic risk by ingestion pathway can be determined by Eq. ( 3 )

where RfD ing is ingestion toxicity reference dose (mg/kg/day). An HQ under 1 is assumed to be safe and taken as significant non-carcinogenic, but HQ value above 1 may indicate a major potential health concern associated with over-exposure of humans to the contaminants 28 .

The total non-carcinogenic risk is represented by hazard index (HI). HI < 1 means the non-carcinogenic risk is acceptable, while HI > 1 indicates the risk is beyond the acceptable level 29 . The HI of a given pollutant through multiple pathways can be calculated by summing the hazard quotients by Eq. ( 4 ) below.

Carcinogenic risks for ingestion pathway is calculated by Eq. ( 5 ). For the selected metals in the study, carcinogenic risk (CR ing ) can be defined as the probability that an individual will develop cancer during his lifetime due to exposure under specific scenarios 30 .

where CRing is carcinogenic risk via ingestion route and SF ing is the carcinogenic slope factor.

Data analysis

Data obtained from the survey were analysed using Microsoft Excel and presented as descriptive statistics in the form of tables and graphs. The experimental data obtained was compared with the South African National Standards (SANS) 31 and Department of Water Affairs and Forestry (DWAF) 32 guidelines for domestic water use.

Ethics approval and consent to participate

The ethical clearance for this study was granted by the University of Venda Health, Safety and Research Ethics’ Committee (SHS/19/PH/14/1104). Permission to conduct the study was obtained from the Department of Water affairs, Limpopo province, Vhembe district Municipality and the selected households. Respondents were duly informed about the study and informed consent was obtained from all of them. The basic ethical principles of voluntary participation, informed consent, anonymity and confidentiality of respondents were duly complied with during data collection, analysis and reporting.

Consent for publication

Not applicable.

Socio-demographic characteristics of respondents

A total of 120 questionnaires were distributed but only 115 were completed, making a good response rate of 95%. The socio-demographic characteristics of the respondents are presented in Table 1 .

Household water supply

Many households (68.7%) had their primary water source from the municipality piped into their yards, but only 5.2% have the water flowing within their houses. The others have to fetch water at their neighbours’ yards or use the public taps on the streets. When the primary water supply is interrupted (i.e. when there is no water flowing through the pipes within the houses, yards or the public taps due to water rationing activities by the municipality, leakage of water distribution pipes, vandalization of pipes during road maintenance, etc.), the interruption usually lasts between a week or two, during which the respondents resort to other alternative sources. A return trip to the secondary source of water usually takes between 10 and 30 min for more than half of the respondents (53.0%) (Table 2 ).

Water storage and treatment practices at the household

Household water was most frequently stored in plastic buckets (n = 78, 67.8%), but ceramic vessels, metal buckets and other containers are also used for water storage (Fig.  2 ). Most households reported that their drinking water containers were covered (n = 111, 96.5%). More than half (53.9%) of the respondents used cups with handles to collect water from the storage containers whereas 37.4% used cups with no handles. Only 7.8% households reported that they treat their water before use mainly by boiling. Approximately 82.6% of respondent are of the opinion that one cannot get sick from drinking water and only 17.4% knew the risks that come with untreated water, and cited diarrhoea, schistosomiasis, cholera, fever, vomiting, ear infections, malnutrition, rash, flu and malaria as specific illnesses associated with water. Despite these perceptions, the majority (76.5%) were satisfied with their current water source. The few (23.5%) who were not satisfied cited poor quality, uncleanness, cloudiness, bad odour and taste in the water as reasons for their dissatisfaction (Table 3 ).

Examples of household water storage containers, some with lids and others without lids (photo from fieldwork).

Sanitation practices at the household level

More than half of the respondents (67%) use pit toilets, whereas only 26.1% use the flush to septic tank system, most of the toilets (93.9%) have a concrete floor. About 76.5% of households do not have designated place to wash their hands, however, all respondents indicated that they always wash their hands with soap or any of its other alternatives before preparing meals and after using the toilet (Table 4 ).

Water samples analysis

The water samples analyses comprise of microbial analysis, physico-chemical analysis and trace metals' parameters.

Microbial analysis

The samples from the reservoir during dry and wet season had 0 MPN/100 mL of total coliform and E. coli and were within the recommended limits of WHO and SANS for drinking water. During the wet season, seven out of the eight water samples collected from the street taps were contaminated with total coliform, while four of the samples taken from the same source were contaminated with total coliform during the dry season. Water samples from street taps 3 and 7 (ST 3 and ST7) were contaminated with total coliform during both seasons, however, the total coliform counts during the wet season were more than the counts during the dry season. None of the samples was contaminated with E. coli during the dry season, however, 2 samples from the street taps (ST3 & ST6) were found to be contaminated with E. coli during the wet season. Samples from household taps showed a similar trend with the street taps—with all samples being contaminated with total coliform during the wet season. Though 7 of the 8 samples taken from the household taps were contaminated with total coliform during the dry season, the samples from the same sources showed a higher level of total coliform in the wet season, with almost all the samples showing contamination at maximum detection levels of more than 2000 MPN/100 mL, except one sample (HT8) which showed a higher level of contamination with total coliform during the dry compared with the wet season. Only one sample (HT4) was found to be contaminated with E. coli during both dry and wet season. This shows that total coliform contamination levels are higher during the wet season than the dry season (Table 5 ).

Water samples from household storage containers (HSC) showed a higher level of total coliform during the wet season than the dry season and more samples were contaminated with E. coli during the wet season also (Table 6 ). A higher level of contamination was recorded for the HSCs compared to the street and household taps.

Physico-chemical analysis

In the reservoir samples, the pH value ranged from 8.37 to 8.45, EC ranged between 183 and 259 µS/cm whereas TDS varied between 118 and 168 mg/L. Similarly, in the street tap samples, pH value ranged from 7.28 and 9.33, EC ranged between 26 and 867 µS/cm whereas TDS varied between 16 and 562 mg/L (Fig.  3 ).

EC and TDS levels for the street taps and reservoir samples.

In the household taps, pH value ranged from 7.70–9.98, EC range between 28–895 µS/cm and TDS varied between 18 and 572 mg/L (Fig.  4 ).

EC and TDS levels for household taps.

In household storage container samples, the pH value ranges from 7.67–9.77, EC ranged between 19–903 µS/cm and TDS values ranged from 12–1148 mg/L (Fig.  5 ).

EC and TDS levels for household storage container samples.

Analysis of cations and trace metals in water

To detect the cations’ and trace metals’ concentrations in the water samples, representative samples from each of the sources were selected for analysis. The concentration of Calcium ranged between 2.14 and 31.65 mg/L, Potassium concentration ranged from 0.14 to 1.85 mg/L, Magnesium concentration varied from 1.32 to 16.59 mg/L, Sodium ranged from 0.18 to 12.96 mg/L (Table 7 ).

Trace metals’ analysis

The minimum and maximum concentrations of trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, As and Pb) present in water samples from selected street taps, household taps and household storage containers are presented in Table 8 .

Hazard quotient (HQ) and carcinogenic risk assessment

Table 9 presents the exposure dosage and hazard quotient (HQ) for ingestion and dermal pathway for metals. The HQ ing and HQ derm for all analyzed trace metals in both children and adults were less than one unit, indicating that there are no potential non-carcinogenic health risks associated with consumption of the water. Table 10 presents the total Hazard Quotient and Health risk index (HI) for trace metals in the water samples, showing that residents of the study area are not susceptible to non-cancer risks due to exposure to trace metals in drinking water. Table 11 presents the cancer risk associated with the levels of Ni, As and Pb in the drinking water samples. The table shows that only the maximum levels of lead had the highest chance of cancer risks for both adults and children.

This study provides information about the quality of drinking water in a selected rural community of Thulamela municipality of Limpopo province, South Africa, taking into consideration the physicochemical, microbiological and trace metals’ parameters of the treated water supplied to the village by the government, through the municipality. Many participants in the study have their primary source of water piped into their yards, while very few have water in their houses. This implies that getting water for household use would involve collecting the water from the yard and then into the storage containers. Those who do not have the taps in their yards have to collect water from the neighbours’ yards or the street taps. This observation is not restricted to the study area, as a similar situation has been observed in other rural communities of Limpopo Province 21 . This need to pass water through multiple containers before the point of use increases the risk of contamination.

Residents of the study area, just like residents of other settlements in Thulamela Municipality 21 , store their drinking water in plastic buckets, ceramic vessels, jerry cans and other containers. Almost all the respondents (96.5%) claim that their water storage vessels are covered and that their drinking water usually stays for less than a week in the storage containers (87.8%). Covering of water storage containers reduces the risk of water contamination from dust or other airborne particles. However, intermittent interruption of municipal water supply lasting for a week or more in the study area and the consequent use of alternative sources of water predispose the residents to various health risks as intermittent interruption in water supply has been linked to higher chances of contamination in the distribution systems, compared with continuous supply; in addition, the alternative sources of water may not be of a good quality as the treated municipal water 33 , 34 , yet, more than half of the respondents in this study (53%) use water directly from source without any form of treatment. This is because many residents in rural communities of Limpopo province believe that the water they drink is of good quality and thus do not need any further treatment 21 . The few who treat their water before drinking mostly use the boiling method. While boiling and other home-based interventions like solar disinfection of water have been reported to improve the quality of drinking water; drinking vessels, like cups, have also been implicated in water re-contamination of treated water at the point of use 16 and most respondents (91.3%) in this study admittedly use cups to collect water from the storage containers. The risk of contamination is even increased when cups without handles are used, where there is a higher chance that the water collector would touch the water in the container with his/her fingers. The Centres for Disease Control and Prevention (CDC) recommends that containers for drinking water should be fitted with a small opening with a cover or a spigot, through which water can be collected while the container remains closed, without dipping any potentially contaminated object into the container 35 . However, it is noteworthy that all the respondents claim to always wash their hands with soap (or its equivalents) and water after using the toilets, a constant practice of hand washing after using the toilet has been associated with a reduced risk of water contamination with E. coli 19 .

Treated water from the dam tested negative for both total coliform and E. coli hence complied with regulatory standards of SANS 31 and WHO 8 . The results could probably be due to the use of chlorine as a disinfectant in the treatment plant. Using disinfectants, pathogenic bacteria from the water can be killed and water made safe for the user. Similar studies have also reported that treated water in urban water treatment plants contains no total coliforms and E. coli 36 . In contrast, treated water sources in rural areas have been reported to have considerable levels of total coliform and E. coli 37 . The reason alluded to this include lack of disinfectant, no residual chlorine in the treated water, high prevalence of open defecation and unhygienic practices in proximity to water sources 38 .

From the water samples collected from the street taps, 62.5% were found to be contaminated with total coliform during the dry season, while the percentage rose to 87.5% during the wet season. The street tap which is about 13 km from the reservoir recorded high levels of total coliform ranging from 1.0 -2000 MPN/100 mL with most of the sites exceeding the WHO guidelines of 10 MPN/100 mL 8 . In both seasons, all the samples tested negative for E. coli , this complies with the WHO guideline of 0 MPN/100 mL. While the water leaving the treatment plant met bacteriological standards, the detection of coliform bacteria in the distribution lines suggest that the water is contaminated in the distribution networks. This could be due to the adherence of bacteria onto biofilms or accidental point source contamination by broken pipes, installation and repair works 39 . Furthermore, the water samples from households’ storage containers were contaminated by total coliform (73% and 85%) and E. coli (10.4% and 13.2%) during the dry and wet season, respectively. Microbiological contamination of household water stored in containers could be due to unhygienic practices occurring between the collection point and the point-of-use 40 , 41 .

Generally, higher levels of contamination were recorded in the wet season than in the dry season. The wet season in Thulamela Municipality is often characterized with increased temperature which could lead to favourable condition for microbial growth. Also, the treatment plant usually makes use of the same amount of chlorine for water purification during both seasons, even though influent water would be of a higher turbidity during the wet season, hence reducing the levels of residual chlorine 42 .

The pH of the analyzed samples from the study area ranged from 7.15 to 9.92. Most of the samples were within the values recommended by SANS (5 to 9.7) and comparable to results from previous similar studies 31 , 43 . Also, the electrical conductivity of all water samples from this study ranged from 28 µS/cm to 903 µS/cm which complied with the recommended value of SANS: < 1700 µS/cm 31 . The presence of dissolved solids such as calcium, chloride, and magnesium in water samples is responsible for its electrical conductivity 44 .

Total dissolved solids are the inorganic salts and small amounts of organic substance, which are present as solution in water 45 . Water has the ability to dissolve a wide range of inorganic and some organic minerals or salts such as potassium, calcium, sodium, bicarbonates, chlorides, magnesium, sulphates, etc. These minerals produced unwanted taste and colour in water 46 . A high TDS value indicates that water is highly mineralised. The recommended TDS value set for drinking water quality is ≤ 1200 mg/L 31 . In this study, the TDS values ranged from 18 mg/L to 572 mg/L. Hence, the TDS of all the household’s storage samples complied with the guidelines and consistent with previous studies 47 .

The analysis of magnesium (1.32 to 16.59 mg/L) and calcium (2.14 to 31.65 mg/L) concentrations showed that they were within the permissible range recommended for drinking water by SANS 31 and WHO 8 . All living organisms depend on magnesium in all types of cells, body tissues and organs for variety of functions while calcium is very important for human cell physiology and bones. Similar studies in Ethiopia and Turkey also showed acceptable levels of these metals in drinking water 46 , 48 . Likewise, the levels of potassium (0.14 to 1.85 mg/L) and sodium (0.18 to 12.96 mg/L) were within the permissible limit of WHO and SANS and may not cause health related problems. Sodium is essential in humans for the regulation of body fluid and electrolytes, and for proper functioning of the nerves and muscles, however, excessive sodium in the body can increase the risk of developing a high blood pressure, cardiovascular diseases and kidney damage 49 , 50 . Potassium is very important for protein synthesis and carbohydrate metabolism, thus, it is very important for normal growth and body building in humans, but, excessive quantity of potassium in the body (hyperkalemia) is characterized with irritability, decreased urine production and cardiac arrest 51 .

Metals like copper (Cu), cobalt (Co) and zinc (Zn) are essential requirements for normal body growth and functions of living organisms, however, in high concentrations, they are considered highly toxic for human and aquatic life 42 . Elevated trace metal(loids) concentrations could deteriorate water quality and pose significant health risks to the public due to their toxicity, persistence, and bio accumulative nature 52 . In this study, the concentrations of Manganese, Cobalt, Nickel and Copper all complied with the recommended concentration by SANS for domestic water use.

Aluminum concentration in the drinking water samples ranged from 1.25—13.46 µg/L. All analysed samples complied with the recommended concentration of ≤ 300 µg/L for domestic water use 31 . The recorded levels of Al in water from this study should not pose any health risk. At a high concentration, aluminium affects the nervous system, and it is linked to several diseases, such as Parkinson’s and Alzheimer’s diseases 53 . Iron (Fe) is an essential element for human health, required for the production of protein haemoglobin, which carries oxygen from our lungs to the other parts of the body. Insufficient or excess levels of iron can have negative effect on body functions 54 . The recommended concentration of iron in drinking water is ≤ 2000 µg/L 31 . In this study, the concentration of iron in the samples ranged from 0.96 to 73.53 µg/L. Similar results were reported by Jamshaid et al. in Khyber Pakhtunkhwa province 55 . A high concentration of Fe in water can give water a metallic taste, even though it is still safe to drink 56 .

The levels of Pb, As and Zn were in the range of 0.02–0.57 µg/L, 0.02–0.17 µg/L, and 2.54–194.96 µg/L, respectively whereas Cr was not detected in the samples collected. The levels recorded complied with the SANS 31 and WHO 8 guidelines for drinking water. Similar results were reported by Mohod and Dhote 57 . Lead is not desirable in drinking water because it is carcinogenic and can cause growth impairment in children 41 . Inorganic arsenic is a confirmed carcinogen and is the most significant chemical contaminant in drinking-water globally 44 . Zinc deficiency can cause loss of appetite, decreased sense of taste and smell, slow wound healing and skin sores 58 . Cr is desirable at low concentration but can be harmful if present in elevated levels.

The hazard quotient (HQ) takes into consideration the oral toxicity reference dose for a trace metal that humans can be exposed to 59 . Health related risk associated with the exposure through ingestion depends on the weight, age and volume of water consumed by an individual. HQ ing and HQ derm for all analyzed trace metals in both children and adults were less than one unit (Table 9 ), indicating that there are no potential non-carcinogenic health risks associated with the consumption of the water from the study area either by children or adults. The calculated average cumulative health risk index (HI) for children and adult was 3.88E-02 and 1.78E-02, respectively. HQ across metals serve as a conservative assessment tool to estimate high-end risk rather than low end-risk in order to protect the public. This served as a screen value to determine whether there is major significant health risk 60 . The results in this study signifies that the population of the investigated area are not susceptible to non-cancer risks due to exposure to trace metals in drinking water. Similar observation has been reported by Bamuwamye et al. after investigating human health risk assessment of trace metals in Kampala (Uganda) drinking water 61 . It should be noted that the hazard index values for children were higher than that of adult, suggesting that children were more susceptible to non-carcinogenic risk from the trace metals.

Drinking water with trace metals such as Pb, As, Cr and Cd could potentially enhance the risk of cancer in human beings 62 , 63 . Long term exposure to low amounts of toxic metals might, consequently, result in many types of cancers. Using As, Ni and Pb carcinogens, the total exposure risks of the residents in Table 11 . For trace metals, an acceptable carcinogenic risk value of less than 1 × 10 −6 is considered as insignificant and the cancer risk can be neglected; while an acceptable carcinogenic risk value of above 1 × 10 –4 is considered as harmful and the cancer risk is worrisome. Amongst the studied trace metals, only the maximum levels of lead for both adults and children had the highest chance of cancer risks (1.93E−03 and 4.46E−03) while Arsenic and Nickel have no chance of cancer risk with values of 3.34E−06; 7.72E−06 and 2.24E−05; 5.18E−05, in both adults and children respectively. The only cancer risk to residents of the studied area could be from the cumulative ingestion of lead in their drinking water. The levels of Pb recorded in this study complied to the SANS guideline value for safe drinking water. While the levels of Pb from the dam and the street pipes were relatively low, higher levels where recorded at household taps and storage containers and this may be due to the kind of storage containers and pipes used in those households. Generally, the water supply is of low Pb levels which should not pose any health risk to the consumers. However, the residents in rural areas should be properly educated on the kind of materials to be used for safe storage of water which should not pose an additional health burden. The likelihood of cancer risk was only associated with the consumption of the highest levels of Pb reported for a life time for adults (set at 70 years) and 6 years for children. Consistent consumption of water from the same source throughout an adult’s lifetime is unlikely as residents in those communities may change their locations at some points, hence reducing the possible risk associated with consistent exposure to the same levels of Pb.

Conclusions

The study shows that as distance increases from the treatment reservoir to distribution points, the cross-contamination rate also increases, therefore, good hygienic practices is required while transporting, storing and using water. Unhygienic handling practices at any point between collection and use contribute to the deterioration of drinking water quality.

The physicochemical, bacteriological quality and trace metals’ concentration of water samples from treated source, street taps and household storage containers were majorly within the permissible range of both WHO and SANS drinking water standards. HQ for both children and adults were less than unity, showing that the drinking water poses less significance health threat to both children and adults. Amongst the studied trace metals, only the maximum level of lead for both adults and children has the highest chance of cancer risks.

We recommend that appropriate measures should be taken to maintain residual free chlorine at the distribution points, supply of municipal treated water should be more consistent in all the rural communities of Thulamela municipality, Limpopo province and residents should be trained on hygienic practices of transportation and storage of drinking water from the source to the point of use.

Data availability

The datasets used and analysed during the current study are available from the first author on reasonable request.

Abbreviations

American Public Health Association

Centres for Disease Control and Prevention

Department of Water Affairs and Forestry

Electrical conductivity

Health risk index

Hazard quotient

Household storage containers

Household taps

Inductively coupled plasma mass spectrophotometer

Inductively coupled plasma optical emission spectrophotometer

Most probable number

South African National Standards

Street taps

Total Dissolved Solids

United Nations General Assembly

United Nations International Children Emergency Fund

United States Environmental Protection Agency

World Health Organization

Taiwo, A.M., Olujimi, O.O., Bamgbose, O. & Arowolo, T.A. Surface water quality monitoring in Nigeria: Situational analysis and future management strategy. In Water Quality Monitoring and Assessment (ed. Voudouris, K) 301–320 (IntechOpen, 2012).

Corcoran, E., et al. Sick water? The central role of wastewater management in sustainable development: A rapid response assessment. United Nations Enviromental Programme UN-HABITAT, GRID-Arendal. https://wedocs.unep.org/20.500.11822/9156 (2010).

United Nations, The 2030 Agenda and the Sustainable Development Goals: An opportunity for Latin America and the Caribbean (LC/G.2681-P/Rev.3), Santiago (2018).

Hubert, E. & Wolkersdorfer, C. Establishing a conversion factor between electrical conductivity and total dissolved solids in South African mine waters. Water S.A. 41 , 490–500 (2015).

Article   CAS   Google Scholar  

Department of Water Affairs (DWA). Groundwater Strategy. Department of Water Affairs: Pretoria, South Africa. 64 (2010).

Lu, Y., Nakicenovic, N., Visbeck, M. & Stevance, A. S. Policy: Five priorities for the UN sustainable development goals. Nature 520 , 432–433 (2015).

Article   ADS   PubMed   Google Scholar  

Shaheed, A., Orgil, J., Montgomery, M. A., Jeuland, M. A. & Brown, J. Why, “improved” water sources are not always safe. Bull. World Health Organ. 92 , 283–289 (2014).

Article   PubMed   PubMed Central   Google Scholar  

WHO. Guidelines for Drinking Water Quality 4th Edn (World Health Organization, Geneva, Switzerland, 2011). http://apps.who.int/iris/bitstream/10665/44584/1/9789241548151_eng.pdf .

Patil, P. N., Sawant, D. V. & Deshmukh, R. N. Physico-chemical parameters for testing of water—a review. Int. J. Environ. Sci. 3 , 1194–1207 (2012).

CAS   Google Scholar  

Bain, R. et al. Fecal contamination of drinking-water in low-and middle-income countries: A systematic review and meta-analysis. PLoS Med. 11 , e1001644 (2014).

Younos, T. & Grady, C.A. Potable water, emerging global problems and solutions. In The Handbook of Environmental Chemistry 30 (2014).

Tigabu, A. D., Nicholson, C. F., Collick, A. S. & Steenhuis, T. S. Determinants of household participation in the management of rural water supply systems: A case from Ethiopia. Water Policy. 15 , 985–1000 (2013).

Article   Google Scholar  

Oljira, G. Investigation of drinking water quality from source to point of distribution: The case of Gimbi Town, in Oromia Regional State of Ethiopia (2015).

Clasen, T., Haller, L., Walker, D., Bartram, J. & Cairncross, S. Cost-effectiveness of water quality interventions for preventing diarrhoeal disease in developing countries. J. Water Health 5 , 599–608 (2007).

Article   PubMed   Google Scholar  

Too, J. K., Sang, W. K., Ng’ang’a, Z. & Ngayo, M. O. Fecal contamination of drinking water in Kericho District, Western Kenya: Role of source and household water handling and hygiene practices. J. Water Health 14 , 662–671 (2016).

Rufener, S., Mausezahl, D., Mosler, H. & Weingartner, R. Quality of drinking-water at source and point-of-consumption—drinking cup as a high potential recontamination risk: A field Study in Bolivia. J. Health Popul. Nutri. 28 , 34–41 (2010).

Google Scholar  

Nsubuga, F. N. W., Namutebi, E. N. & Nsubuga-ssenfuma, M. Water resources of Uganda: An assessment and review. Water Resour. Prot. 6 , 1297–1315 (2014).

Rawway, M., Kamel, M. S. & Abdul-raouf, U. M. Microbial and physico-chemical assessment of water quality of the river Nile at Assiut Governorate (Upper Egypt). J. Ecol. Health Environ. 4 , 7–14 (2016).

Agensi, A., Tibyangye, J., Tamale, A., Agwu, E. & Amongi C. Contamination potentials of household water handling and storage practices in Kirundo Subcounty, Kisoro District, Uganda. J. Environ. Public Health. Article ID 7932193, 8 pages (2019).

Mahmud, Z. H. et al. Occurrence of Escherichia coli and faecal coliforms in drinking water at source and household point-of-use in Rohingya camps, Bangladesh. Gut Pathog. 11 , 52. https://doi.org/10.1186/s13099-019-0333-6 (2019).

Edokpayi, J. N. et al. Challenges to sustainable safe drinking water: A case study of water quality and use across seasons in rural communities in Limpopo Province, South Africa. Water 10 , 159 (2018).

Article   PubMed   PubMed Central   CAS   Google Scholar  

Musyoki, A., Thifhulufhelwi, R. & Murungweni, F. M. The impact of and responses to flooding in Thulamela Municipality, Limpopo Province, South Africa, Jàmbá. J. Disaster Risk Stud. 8 , 1–10 (2016).

Census 2011. Main Place: Lufule. Accessed from Census 2011: Main Place: Lufule (adrianfrith.com) on 30/01/2022.

Bolarinwa, O. A. Principles and methods of validity and reliability testing of questionnaires used in social and health science researches. Niger. Postgrad. Med. J. 22 , 195–201 (2015).

Association, A. P. H. Standard Methods for the Examination of Water and Waste Water 16th edn. (American Public Health Association, Washington, 1992).

Bernardes, C., Bernardes, R., Zimmer, C. & Dorea, C. C. A simple off-grid incubator for microbiological water quality analysis. Water 12 , 240 (2020).

Rich CR, Sellers JM, Taylor HB, IDEXX Laboratories Inc. Chemical reagent test slide. U.S. Patent Application 29/218,589. (2006).

Naveedullah, et al. Concentrations and human health risk assessment of selected heavy metals in surface water of siling reservoir watershed in Zhejiang Province, China. Pol. J. Environ. Stud. 23 , 801–811 (2014).

Wu, J. & Sun, Z. Evaluation of shallow groundwater contamination and associated human health risk in an alluvial plain impacted by agricultural and industrial activities, mid-west China. Expos. Health. 8 , 311–329 (2016).

Wu, L., Zhang, X. & Ju, H. Amperometric glucose sensor based on catalytic reduction of dissolved oxygen at soluble carbon nanofiber. Biosens. Bioelectron. 23 , 479–484 (2007).

Article   PubMed   CAS   Google Scholar  

South African National Standard (SANS). 241-1: Drinking Water, Part 1: Microbiological, Physical, Aesthetic and Chemical Determinants. 241-2: 2015 Drinking Water, Part 2: Application of SANS 241-1 (2015).

Department of Water Affairs and Forestry (DWAF). South African Water Quality Guidelines (second edition). Volume 1: Domestic Use, (1996).

Drake, M.J. & Stimpfl, M. Water matters. In Lunar and Planetary Science Conference , Vol. 38, 1179 (2007).

Kumpel, E. & Nelson, K. L. Intermittent water supply: prevalence, practice, and microbial water quality. Environ. Sci. Technol. 50 , 542–553 (2016).

Article   ADS   CAS   PubMed   Google Scholar  

Centers for Disease Control and Prevention. The safe water system: Safe storage of drinking water. Accessed from CDC Fact Sheet on 30/01/2022 (2012).

Hashmi, I., Farooq, S. & Qaiser, S. Chlorination and water quality monitoring within a public drinking water supply in Rawalpindi Cantt (Westridge and Tench) area, Pakistan. Environ. Monit. Assess. 158 , 393–403 (2009).

Article   CAS   PubMed   Google Scholar  

Onyango, A. E., Okoth, M. W., Kunyanga, C. N. & Aliwa, B. O. Microbiological quality and contamination level of water sources in Isiolo country in Kenya. J. Environ. Public Health . 2018 , 2139867 (2018).

Gwimbi, P., George, M. & Ramphalile, M. Bacterial contamination of drinking water sources in rural villages of Mohale Basin, Lesotho: Exposures through neighbourhood sanitation and hygiene practices. Environ. Health Prev. Med. 24 , 33 (2019).

Karikari, A. Y. & Ampofo, J. A. Chlorine treatment effectiveness and physico-chemical and bacteriological characteristics of treated water supplies in distribution networks of Accra-Tema Metropolis, Ghana. Appl. Water Sci. 3 , 535–543 (2013).

Article   ADS   CAS   Google Scholar  

Thompson, T., Sobsey, M. & Bartram, J. Providing clean water, keeping water clean: An integrated approach. Int. J. Environ. Health Res. 13 , S89–S94 (2003).

Cronin, A. A., Breslin, N., Gibson, J. & Pedley, S. Monitoring source and domestic water quality in parallel with sanitary risk identification in Northern Mozambique to Prioritise protection interventions. J. Water Health 4 , 333–345 (2006).

Edokpayi, J. N., Enitan, A. M., Mutileni, N. & Odiyo, J. O. Evaluation of water quality and human risk assessment due to heavy metals in groundwater around Muledane area of Vhembe District, Limpopo Province, South Africa. Chem. Cent. J. 12 , 2 (2018).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Edimeh, P. O., Eneji, I. S., Oketunde, O. F. & Sha’Ato, R. Physico-chemical parameters and some heavy metals content of Rivers Inachalo and Niger in Idah, Kogi State. J. Chem. Soc. Nigeria 36 , 95–101 (2011).

Rahmanian, N., et al . Analysis of physiochemical parameters to evaluate the drinking water quality in the State of Perak, Malaysia. J. Chem. 1–10. Article ID 716125 (2015).

WHO/FAO. Diet, Nutrition, and the Prevention of Chronic Diseases (World Health Organisation, Geneva, 2003).

Meride, Y. & Ayenew, B. Drinking water quality assessment and its effects on resident’s health in Wondo genet campus, Ethiopia. Environ. Syst. Res. 5 , 1 (2016).

Mapoma, H. W. & Xie, X. Basement and alluvial aquifers of Malawi: An overview of groundwater quality and policies. Afr. J. Environ. Sci. Technol. 8 , 190–202 (2014).

Soylak, M., Aydin, F., Saracoglu, S., Elci, L. & Dogan, M. Chemical analysis of drinking water samples from Yozgat. Turkey Pol. J. Environ. Stud. 11 , 151–156 (2002).

Munteanu, C. & Iliuta, A. The role of sodium in the body. Balneo Res. J. 2 , 70–74 (2011).

Strazzullo, P. & Leclercq, C. Sodium. Adv. Nutr. 5 , 188–190 (2014).

Pohl, H. R., Wheeler, J. S. & Murray, H. E. Sodium and potassium in health and disease. Met. Ions Life Sci. 13 , 29–47 (2013).

Muhammad, S., Shah, M. T. & Khan, S. Health risk assessment of heavy metals and their source apportionment in drinking water of Kohistan region, northern Pakistan. Microchem. J. 98 , 334–343 (2011).

Inan-Eroglu, E. & Ayaz, A. Is aluminum exposure a risk factor for neurological disorders?. J. Res. Med. Sci. 23 , 51 (2018).

Milman, N. Prepartum anaemia: Prevention and treatment. Ann. Hematol. 87 , 949–959 (2008).

Jamshaid, M., Khan, A. A., Ahmed, K. & Saleem, M. Heavy metal in drinking water its effect on human health and its treatment techniques—a review. Int. J. Biosci. 12 , 223–240 (2018).

Tagliabue, A., Aumont, O. & Bopp, L. The impact of different external sources of iron on the global carbon cycle. Geophys. Res. Lett. 41 , 920–926 (2014).

Mohod, C. V. & Dhote, J. Review of heavy metals in drinking water and their effect on human health. Int. J. Innov. Res. Technol. Sci. Eng. 2 , 2992–2996 (2013).

Bhowmik, D., Chiranjib, K. P. & Kumar, S. A potential medicinal importance of zinc in human health and chronic. Int. J. Pharm. 1 , 05–11 (2010).

Mahmud, M. A. et al. Low temperature processed ZnO thin film as electron transport layer for efficient perovskite solar cells. Sol. Energy Mater. Sol. Cells. 159 , 251–264 (2017).

Rajan, S. & Ishak, N. S. Estimation of target hazard quotients and potential health risks for metals by consumption of shrimp ( Litopenaeus vannamei ) in Selangor, Malaysia. Sains Malays. 46 , 1825–1830 (2017).

Bamuwamye, M. et al. Human health risk assessment of heavy metals in Kampala (Uganda) drinking water. J. Food Res. 6 , 6–16 (2017).

Saleh, H. N. et al. Carcinogenic and non-carcinogenic risk assessment of heavy metals in groundwater wells in Neyshabur Plain, Iran. Biol. Trace Elem. Res. 190 , 251–261 (2019).

Tani, F. H. & Barrington, S. Zinc and copper uptake by plants under two transpiration rates Part II Buckwheat ( Fagopyrum esculentum L.). Environ. Pollut. 138 , 548–558 (2005).

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Acknowledgements

The authors wish to thank the University of Venda Health, Safety and Research Ethics’ Committee, the Department of Water affairs, Limpopo province and Vhembe district Municipality for granting the permission to conduct this study. We also thank all the respondents from the selected households in Lufule community.

The study was funded by the Research and Publication Committee of the University of Venda (Grant number: SHS/19/PH/14/1104).

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L.N. and J.N.E. conceptualized the study, L.N. collected and analysed the data, T.G.T., J.T. M., and J.N.E. supervised the data collection and analysis. F.C.O. drafted the original manuscript, J.N.E. reviewed and edited the original manuscript. All authors approved the final manuscript.

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Luvhimbi, N., Tshitangano, T.G., Mabunda, J.T. et al. Water quality assessment and evaluation of human health risk of drinking water from source to point of use at Thulamela municipality, Limpopo Province. Sci Rep 12 , 6059 (2022). https://doi.org/10.1038/s41598-022-10092-4

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EPA Awards $1M in Research Funding to Implement Drinking Water Treatment for Manganese in Small Communities

September 13, 2024

WASHINGTON – Today, September 13, the U.S. Environmental Protection Agency announced $1,000,000 in research grant funding to Cornwell Research Group in Newport News, Virginia, to evaluate the effectiveness of common manganese treatment technologies. This will provide states, Tribes and small utilities with an improved ability to adopt and implement these treatment technologies in small drinking water systems.

“The funding announced today will help our small drinking water systems meet public health requirements with fewer resources,” said Assistant Administrator for EPA’s Office of Research and Development Chris Frey . “This research will help identify and find treatment solutions that address unique challenges that small communities face when providing clean drinking water.”

Manganese, an essential element in the human diet, is naturally occurring in the environment and prevalent throughout the United States in groundwater and surface water. However, higher concentrations have been found to potentially lead to negative neurological health impacts in vulnerable populations. Small public water systems (serving 10,000 or fewer customers) frequently lack the resources and capacity to adopt and maintain manganese treatment systems. Supporting the development of affordable, efficient, and user-friendly manganese treatment technologies will better enable small, rural, and Tribal systems to address health concerns.

The research team at Cornwell Research Group will evaluate manganese treatment costs and performance of small water systems to determine the most appropriate treatment solutions for multiple site scenarios. Recommendations will be made available to stakeholders through site visits, workshops, webinars, and a website. This work is expected to help small utilities implement and maintain manganese treatment for their drinking water.

Learn more about the funded recipient and learn more about EPA research grants .

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Why drinking water won’t cure your hangover: new research.

There’s a persistent belief that chugging water after a night of drinking can counteract the effects of too much booze, but experts say it does little to prevent the fresh hell of a hangover.

Using data from three studies, researchers from Utrecht University in the Netherlands concluded that dehydration is not the sole cause of a hangover — meaning that drinking water has a limited effect on the body’s recovery.

The review tracked the hangover symptoms of boozers who drank water before bed versus those who didn’t. Results showed that those who drank water felt less dehydrated but experienced the same degree of pain, nausea, and exhaustion as those who chose to forgo the H 2 O.

Researchers concluded that ­consuming water during or directly after a drinking session is ineffective in preventing hangovers. Further, drinking water after the hangover had set in was not shown to alleviate the severity of symptoms.

Dr. Johnny Parvani, REVIV founder and chief medical officer, previously told  The Post , “A hangover is a clinical condition that is characterized by a combination of effects from alcohol metabolism and dehydration,” supporting the claim that a hangover includes but is not limited to dehydration.

According to the review, dehydration is caused by the loss of water and electrolytes due to the activation of the hormone system that regulates blood pressure, fluid, and electrolyte balance. Meanwhile, the hallmark effects of an alcohol hangover are the result of oxidative stress and the body’s inflammatory response to alcohol consumption.

Dehydration triggers thirst, a common symptom of the morning after, but studies show that thirst and dehydration are relatively short-lived. However, the other pains associated with drinking tend to persist throughout the day.

According to lead author Dr Joris Verster from Utrecht University, the relationship between drinking and punishment is straightforward, “The more you drink, the more likely you are to get a hangover. Drinking water may help against thirst and a dry mouth, but it will not take away the misery, the headache and the nausea.”

The review concludes “that hangovers and dehydration are two co-occurring but independent consequences of alcohol consumption.”

Anecdotal evidence suggests that  hangovers worsen over time .

Research shows  that as we age, our liver function declines, our bodies have less water, and we lose muscle mass. This may mean a higher concentration of alcohol remains in our bloodstream, and a mightier hangover awaits us the morning after.

Despite a clear demand and consumers’ serious needs, there is currently no commercially available, scientifically proven hangover treatment.

While abstaining from alcohol is your best defense against its crippling consequences, a dietician recently offered her go-to foods and drinks to offset the effects of over-imbibing.

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