Drinking Water Quality and Human Health

The quality of drinking water is paramount for public health. Despite important improvements in the last decades, access to safe drinking water is not universal. The World Health Organization estimates that almost 10% of the population in the world do not have access to improved drinking water sources. Among other diseases, waterborne infections cause diarrhea, which kills nearly one million people every year, mostly children under 5 years of age. On the other hand, chemical pollution is a concern in high-income countries and an increasing problem in low- and middle-income countries. Exposure to chemicals in drinking water may lead to a range of chronic non-communicable diseases (e.g., cancer, cardiovascular disease), adverse reproductive outcomes, and effects on children’s health (e.g., neurodevelopment), among other health effects. Although drinking water quality is regulated and monitored in many countries, increasing knowledge leads to the need for reviewing standards and guidelines on a nearly permanent basis, both for regulated and newly identified contaminants. Drinking water standards are mostly based on animal toxicity data, and more robust epidemiologic studies with accurate exposure assessment are needed. The current risk assessment paradigm dealing mostly with one-by-one chemicals dismisses the potential synergisms or interactions from exposures to mixtures of contaminants, particularly at the low-exposure range. Thus, evidence is needed on exposure and health effects of mixtures of contaminants in drinking water. Finally, water stress and water quality problems are expected to increase in the coming years due to climate change and increasing water demand by population growth, and new evidence is needed to design appropriate adaptation policies.This Special Issue of International Journal of Environmental Research and Public Health (IJERPH) focuses on the current state of knowledge on the links between drinking water quality and human health

Subproductes de la desinfecció de l'aigua potable i càncer de bufeta urinària

Consultable des del TDXTítol obtingut de la portada digitalitzadaAntecedents: La cloració de l'aigua genera trihalometans (THM) i altres subproductes de la desinfecció (DBP) amb propietats carcinògenes. L'exposició a llarg termini a aquests compostos s'ha associat amb un increment del risc de càncer de bufeta, però les evidències no són concloents. Objectius: -Determinar l'exposició a THM com a indicadors del total de DBP en la població d'estudi. -Estimar el risc de càncer de bufeta per exposició a THM. Metodologia: (1) Meta-anàlisi d'estudis sobre consum individual d'aigua clorada i càncer de bufeta. Es va fer una cerca bibliogràfica i es van seleccionar estudis que avaluaven càncer de bufeta i consum individual d'aigua clorada a llarg termini, tot incloent sis estudis cas-control (6084 casos de càncer de bufeta, 10816 controls), i dos estudis cohort (121 casos) que complien els criteris d'inclusió. Es van extreure les odds ratios (OR) o els riscs relatius (RR), més els intervals de confiança al 95% (95%CI) per sexe i categoria d'exposició. Es va fer una meta-anàlisi per les diferents categories d'exposició. (2) Anàlisi de dades combinades (pooled analysis) de sis estudis cas-control de càncer de bufeta, que proporcionaven dades quantitatives sobre nivells d'exposició a THM i consum individual d'aigua. S'han inclòs dos estudis dels EEUU, i un de Canadà, França, Itàlia, i Finlàndia respectivament. Es van extreure de les bases de dades originals variables d'exposició i covariables, combinant-se tot seguint definicions comunes. L'anàlisi inclou 2806 casos i 5254 controls. Es va calcular l'exposició acumulada a THM (mg). Les OR i 95%CI es van estimar a través de regressió logística tot ajustant per estudi i factors confusors potencials. (3) Estudi multicèntric cas-control de càncer de bufeta. La població d'estudi prové de 18 hospitals participants a Astúries, Alacant, Barcelona i Tenerife. S'ha avaluat l'exposició a THM de la població d'estudi a través d'entrevistes personals a 1226 casos i 1271 controls, determinacions de THM a mostres d'aigua, i recull de dades retrospectives de THM a través de qüestionaris a empreses d'aigua i ajuntaments. Es calculen les OR i 95%CI a través de regressió logística per categories d'exposició a THM tot ajustant per àrea i factors de confusió potencials. L'anàlisi es limita als individus amb informació d'exposició ≥70% de la finestra d'exposició, tot excloent-se individus amb qualitat global de l'entrevista qüestionable o insatisfactòria. Resultats: (1) Haver consumit alguna vegada aigua clorada s'associa amb un increment del risc de càncer de bufeta en homes (OR combinada=1.4, 95%CI=1.1-1.9) i dones (OR combinada=1.2, 95%CI=0.7-1.8). (2) Les OR ajustades en homes exposats a >15 mg THM, comparats amb els exposats a 1000 mg (p trend 35 mg/dia en relació a 0 mg/dia era de 1.55, 95%CI=1.02-2.35. Els homes que han estat a la piscina >630 hores al llarg de la vida tenen una OR de 2.08 (95%CI=1.06-4.09) respecte els que mai havien nedat. Conclusions principals: 1. Algunes poblacions espanyoles estan altament exposades als subproductes de la cloració, tant en l'actualitat com en el passat 2. Els resultats conjunts reforcen la hipòtesi que l'exposició a THM a llarg termini, a nivells que s'observen en molts països industrialitzats, s'associa amb un increment del risc de càncer de bufeta. 3. El gènere resulta ser modificador de l'efecte, amb una major associació observada en homes. 4. Trobem una associació entre assistència a piscines i risc de càncer de bufeta. Aquests resultats s'han d'interpretar amb precaució donat que és el primer estudi que avalua aquestes vies d'exposició i calen estudis confirmatius.Background: Chlorination of drinking water generates trihalomethanes (THM) and other carcinogenic disinfection by-products (DBP). Long-term exposure to these compounds has been associated with an increased bladder cancer risk, although evidence is not conclusive yet. Objectives: -Assess the THM exposure in the study population, as a marker of total DBP level. -Estimate the bladder cancer risk associated to THM exposure. Methodology: (1) Meta-analysis of studies on chlorinated drinking water consumption and bladder cancer. We did a bibliographic search and selected studies evaluating individual long-term patterns of chlorinated drinking water consumption and bladder cancer. Six case-control studies were included (6.084 bladder cancer cases, 10.816 controls) and two cohort studies (124 cases) fulfilling the inclusion criteria. Odds ratios (OR) or relative risks (RR) plus 95% confidence intervals (95% CI) by sex and exposure category were extracted. We performed meta-analysis for the different exposure categories. (2) Pooled analysis of six case-control studies on bladder cancer and chlorination by-products, providing quantitative data about THM exposure levels and individual water consumption. Two studies were included from the USA, and one each from Canada, France, Italy and Finland. We extracted from the original databases exposure variables and covariates, combined using common definitions. The analysis included 2806 cases and 5254 controls. We calculated cumulative THM exposure (mg). OR and 95%CI were estimated using logistical regression adjusting by study and potential confounders. (3) Spanish case-control study of bladder cancer. Study subjects come from the 18 participating hospitals in Asturias, Alacant, Barcelona and Tenerife. THM exposure in the study population was assessed through personal interviews to 1226 cases and 1271 controls, THM measurements in 105 water samples from the study areas, and collection of retrospective THM levels through questionnaires to water companies and local authorities. OR and 95%CI were calculated using logistic regression adjusting by area and potential confounders. Analysis was limited to those subjects with exposure information ≥70% from the exposure window and subjects with unsatisfactory or questionable overall quality of interview were excluded. Results: (1) Ever consumption of chlorinated drinking water was associated with an increased bladder cancer risk in men (combined OR=1.4, 95%CI=1.1-1.9) and women (combined OR=1.2, 95%CI=0.7-1.8). (2) The adjusted odds ratio (OR) in men exposed >15 mg/l THM, compared to those with lower or no exposure, was 1.31 (95%CI=1.15-1.50). A monotonic increase in risk with increasing exposure was observed with an OR of 1.51 (95%CI=1.23-1.84) for exposure >1000 mg/l (p trend35 mg/day related to 0 mg/day was 1.55, 95% CI= 1.02-2.35 (p trend=0.030). Those men swimming in the pool >630 hours in their lifetime had an OR of 2.08 (95% CI=1.06-4.09) in relation to those who had never swam. Main Conclusions: 1. Some Spanish areas are highly exposed to chlorination by-products, both currently and in the past. 2. The combined results strengthen the hypothesis that long-term exposure to THM at levels currently observed in many industrialized countries are associated with an increased bladder cancer risk. 3. Gender acts as an effect modifier, with a higher association observed among men 4. We find an association between swimming pool attendance and an increased bladder cancer risk. These results should be cautiously interpreted, since it's the first study assessing these exposure routs and there's a need for specific studies to confirm these results

Risc i efectes a la salut de la desinfecció de l'aigua : una aproximació a la relació entre els subproductes de la cloració de l'aigua i el càncer colorectal

Aquest projecte es centra en l'estimació del risc ambiental que suposen els subproductes de la desinfecció de l'aigua (amb els trihalometans com a marcadors) per a la incidència de càncer colorectal. Això s'estudia mesurant les exposicions i usos de l'aigua d'un grup de casos i controls a diversos llocs de l'Estat Espanyol, comparant els nivells de trihalometans d'aquestes ciutats, estimant-ne l'absorció i, per últim, calculant-ne el risc mitjançant la odds ratio (probabilitat de patir la malaltia dividit per la probabilitat de no desenvolupar-la). Per assolir-ho és vital l'acurada estimació de l'exposició de la població a aquests productes, ja que, tot i que l'aigua de xarxa és una exposició ubiqua i, per tant, ambiental, hi ha persones més exposades que d'altres. Comparant els nivells de trihalometans arreu d'Espanya, la qualitat de l'aigua de consum varia molt als diferents llocs d'estudi, essent Barcelona la de pitjor qualitat ambiental i Guipúscoa la millor. La primera estimació al risc (l'estudi oficial, dut a terme pel Centre de Recerca en Epidemiologia Ambiental, no està conclòs) dóna positiu en la majoria d'exposicions, amb l'excepció de l'assistència a piscines durant l'hivern.This project is centered on the risk assessment related to desinfection by-products (using trihalomethanes as guide) and the incidence of colorectal cancer. This is approached comparing the uses of water in a case-control study held in different cities of Spain, measuring the levels of trihalomethanes in tap water, measuring the exposure and uptake of the participants and working out the odds ratio (chances of having the illness divided by the chances of not having it). To achieve this, it is very important to calculate the real exposure accurately, because, even though tap water is an ubiquitous factor, and, therefore, an environmental one, people's habits are an important factor as well. The concentration of trihalomethanes in water varies significantly in the different cities where the study was done, Barcelona's being that of worst quality and Guipuzcoa's, the best. The rough first approach to the risk assessment (the official study, by the Centre de Recerca d'Epidemiologia Ambiental, is still not closed) is positive in all expositions except the attendance to closed swimming pools

Weather and gastrointestinal disease in Spain: A retrospective time series regression study

BACKGROUND: A few studies in high-income countries have investigated the relationship between ambient temperature and/or precipitation and the occurrence of gastroenteritis. In most of the cases, hot temperatures and heavy precipitation events have been related to increases in infections. This is of concern as climate change predictions indicate an increase of those extreme events. Our aim was to evaluate the association between meteorological variables and daily gastroenteritis hospitalizations in Spain for the period 1997-2013. METHODS: We obtained data on all hospitalizations which occurred in Spain for the study period from administrative databases and selected those with gastroenteritis as the main diagnosis. Meteorological data was obtained from the European Climate Assessment & Dataset. Daily counts of hospitalizations were linked to meteorological variables in a retrospective ecological time series study using quasi-Poisson regression models with overdispersion and applying the Distributed Lag Non-linear Model (DLNM) framework. RESULTS: Both high and cold temperatures increased the risk of gastroenteritis hospitalizations (relative risk (RR) = 1.21, 95% confidence interval (CI): 1.09, 1.34; and RR = 1.07, 95% CI: 1.00, 1.15, respectively), whereas heavy precipitation was found protective for those hospitalizations (RR = 0.74, 95% CI: 0.63, 0.86). Hot temperatures increased hospitalizations for gastroenteritis classified as foodborne or idiopathic but not those in the group of Others, which were composed mainly of infections by rotavirus and were associated with cold temperatures. CONCLUSIONS: Our findings suggest an important role of ambient temperatures, especially hot temperatures, in increasing gastroenteritis hospitalizations, while the exposure to heavy precipitation events pose opposite and unexpected effects on these infections

Non targeted screening of nitrogen containing disinfection by-products in formation potential tests of river water and subsequent monitoring in tap water samples

The generation of disinfection by-products during water chlorination is a major concern in water treatment, given the potential health risks that these substances may pose. In particular, nitrogen-containing DBPs are believed to have greater toxicological significance than carbon-based DBPs. Hence, high performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC-HRMS) in positive mode was employed to identify new non-volatile nitrogen containing disinfection by-products (DBPs) and to assess their presence in potable water. Nine water samples were taken in the Llobregat river, in the context of a water reuse trial, near the catchment of a drinking water treatment plant (DWTP) in 2019. River samples were disinfected with chlorine under controlled formation potential tests conditions and analysed with a non-target approach. The peak lists of raw and chlorinated samples were compared exhaustively, resulting in an extensive list of 495 DBPs that include bromine and/or chlorine atoms. 172 of these species were found frequently, in three or more chlorinated samples. The empirical formulae of these DBPs were unambiguously annotated on the basis of accurate m/z measurements, isotopic patterns and common heuristic rules. Most of the annotated species (310) contained bromide, which is consistent with the relatively high bromide content of the Llobregat basin (>0.3 mg/l). Drinking water samples were taken at the outlet of the DWTP during the same sampling period. According to their analysis, a large portion of the DBPs detected after the formation potential tests do not reach real-life drinking water, which suggests that the treatment train successfully removes a significant fraction of DBP precursors. However, 131 DBPs could still be detected in the final product water. A larger sampling was carried in the Barcelona water distribution network, during six consecutive weeks, and it revealed the presence of 78 halogenated DBPs in end-consumer water, most of which were nitrogen-containing. MS/MS fragmentation and retention times were employed to tentatively suggest molecular structure for these recalcitrant DBPs

Trihalomethane concentrations in tap water as determinant of bottled water use in the city of Barcelona

Bottled water consumption is increasing worldwide, despite its huge economic and environmental cost. We aim to describe personal and tap water quality determinants of bottled water use in the city of Barcelona. This cross-sectional study used data from the Health Survey of Barcelona in 2006 (N=5417 adults). The use of bottled water to drink and to cook was evaluated in relation to age, gender, educational level, district and levels of trihalomethanes (THMs), free chlorine, conductivity, chloride, sodium, pH, nitrate and aluminium in municipal tap water using Robust Poisson Regression. The prevalence of bottled water use to drink and cook was 53.9% and 6.7%, respectively. Chemical parameters in water had a large variability (interquartile range of THMs concentrations: 83.2-200.8μg/L) and were correlated between them, except aluminium. Drinking bottled water increased with educational level, while cooking with bottled water was higher among men than among women and decreased with age. After adjusting by these personal determinants, a dose-response relationship was found between concentrations of all chemicals except aluminium in tap water and bottled water use. The highest association was found for THMs, with a Prevalence Ratio of 2.00 (95%CI=1.86, 2.15) for drinking bottled water and 2.80 (95%CI=1.72, 4.58) for cooking with bottled water, among those with >150μg/L vs. <100μg/L THMs in tap water. CONCLUSION: More than half of Barcelona residents regularly drank bottled water, and the main determinant was the chemical composition of tap water, particularly THM level

Risc i efectes a la salut de la desinfecció de l'aigua : una aproximació a la relació entre els subproductes de la cloració de l'aigua i el càncer colorectal

Aquest projecte es centra en l'estimació del risc ambiental que suposen els subproductes de la desinfecció de l'aigua (amb els trihalometans com a marcadors) per a la incidència de càncer colorectal. Això s'estudia mesurant les exposicions i usos de l'aigua d'un grup de casos i controls a diversos llocs de l'Estat Espanyol, comparant els nivells de trihalometans d'aquestes ciutats, estimant-ne l'absorció i, per últim, calculant-ne el risc mitjançant la odds ratio (probabilitat de patir la malaltia dividit per la probabilitat de no desenvolupar-la). Per assolir-ho és vital l'acurada estimació de l'exposició de la població a aquests productes, ja que, tot i que l'aigua de xarxa és una exposició ubiqua i, per tant, ambiental, hi ha persones més exposades que d'altres. Comparant els nivells de trihalometans arreu d'Espanya, la qualitat de l'aigua de consum varia molt als diferents llocs d'estudi, essent Barcelona la de pitjor qualitat ambiental i Guipúscoa la millor. La primera estimació al risc (l'estudi oficial, dut a terme pel Centre de Recerca en Epidemiologia Ambiental, no està conclòs) dóna positiu en la majoria d'exposicions, amb l'excepció de l'assistència a piscines durant l'hivern.This project is centered on the risk assessment related to desinfection by-products (using trihalomethanes as guide) and the incidence of colorectal cancer. This is approached comparing the uses of water in a case-control study held in different cities of Spain, measuring the levels of trihalomethanes in tap water, measuring the exposure and uptake of the participants and working out the odds ratio (chances of having the illness divided by the chances of not having it). To achieve this, it is very important to calculate the real exposure accurately, because, even though tap water is an ubiquitous factor, and, therefore, an environmental one, people's habits are an important factor as well. The concentration of trihalomethanes in water varies significantly in the different cities where the study was done, Barcelona's being that of worst quality and Guipuzcoa's, the best. The rough first approach to the risk assessment (the official study, by the Centre de Recerca d'Epidemiologia Ambiental, is still not closed) is positive in all expositions except the attendance to closed swimming pools

Weather and gastrointestinal disease in Spain: A retrospective time series regression study

BACKGROUND: A few studies in high-income countries have investigated the relationship between ambient temperature and/or precipitation and the occurrence of gastroenteritis. In most of the cases, hot temperatures and heavy precipitation events have been related to increases in infections. This is of concern as climate change predictions indicate an increase of those extreme events. Our aim was to evaluate the association between meteorological variables and daily gastroenteritis hospitalizations in Spain for the period 1997-2013. METHODS: We obtained data on all hospitalizations which occurred in Spain for the study period from administrative databases and selected those with gastroenteritis as the main diagnosis. Meteorological data was obtained from the European Climate Assessment & Dataset. Daily counts of hospitalizations were linked to meteorological variables in a retrospective ecological time series study using quasi-Poisson regression models with overdispersion and applying the Distributed Lag Non-linear Model (DLNM) framework. RESULTS: Both high and cold temperatures increased the risk of gastroenteritis hospitalizations (relative risk (RR) = 1.21, 95% confidence interval (CI): 1.09, 1.34; and RR = 1.07, 95% CI: 1.00, 1.15, respectively), whereas heavy precipitation was found protective for those hospitalizations (RR = 0.74, 95% CI: 0.63, 0.86). Hot temperatures increased hospitalizations for gastroenteritis classified as foodborne or idiopathic but not those in the group of Others, which were composed mainly of infections by rotavirus and were associated with cold temperatures. CONCLUSIONS: Our findings suggest an important role of ambient temperatures, especially hot temperatures, in increasing gastroenteritis hospitalizations, while the exposure to heavy precipitation events pose opposite and unexpected effects on these infections

Ingested Nitrate and Breast Cancer in the Spanish Multicase-Control Study on Cancer (MCC-Spain).

BACKGROUND: Ingested nitrate leads to endogenous formation of N-nitroso compounds that are breast carcinogens in animals, but human evidence is limited. OBJECTIVE: We evaluated ingested nitrate as a risk factor for breast cancer (BC) in a multicase-control study. METHODS: Hospital-based incident BC cases and population-based controls were recruited in eight Spanish regions in 2008-2013; participants provided residential and water consumption from 18 years of age and information on known BC risk factors. Long-term nitrate levels (1940-2010) were estimated and linked with residential histories and water consumption to calculate waterborne ingested nitrate (milligrams/day). Dietary ingested nitrate (milligrams/day) was calculated using food frequency questionnaires and published dietary nitrate contents. Interactions with endogenous nitrosation factors and other variables were evaluated. A total of 1,245 cases and 1,520 controls were included in the statistical analysis. RESULTS: Among the study regions, average ± SD waterborne ingested nitrate ranged from 2.9 ± 1.9 to 13.5 ± 7.5 mg/day, and dietary ingested nitrate ranged from 88.5 ± 48.7 to 154 ± 87.8 mg/day. Waterborne ingested nitrate was not associated with BC overall, but among postmenopausal women, those with both high nitrate (> 6 vs. < 2.6 mg/day) and high red meat intake (≥ 20 vs. < 20 g/day) were more likely to be cases than women with low nitrate and low red meat intake (adjusted odds ratio = 1.64; 95% confidence interval: 1.08, 2.49; overall interaction p-value = 0.17). No association was found with dietary nitrate. CONCLUSIONS: Waterborne ingested nitrate was associated with BC only among postmenopausal women with high red meat consumption. Dietary nitrate was not associated with BC regardless of the animal or vegetable source or of menopausal status.This study was funded by the “Acción Transversal del Cáncer del Consejo de Ministros del 11/10/2007” from the “Instituto de Salud Carlos III-FEDER” (PI08/1770, PI08/0533, PI11/00226), ISCIII FIS grants. N.E.H. received financial support for the Ph.D. program from the “Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR FI-DGR 2013) Generalitat de Cataluña.

Risks and benefits of green spaces for children: A cross-sectional study of associations with sedentary behavior, obesity, asthma, and allergy

Background: Green spaces have been associated with both health benefits and risks in children; however, available evidence simultaneously investigating these conflicting influences, especially in association with different types of greenness, is scarce. Objectives: We aimed to simultaneously evaluate health benefits and risks associated with different types of greenness in children, in terms of sedentary behavior (represented by excessive screen time), obesity, current asthma, and allergic rhinoconjunctivitis. Methods: We conducted a cross-sectional study of a population-based sample of 3,178 schoolchildren (9–12 years old) in Sabadell, Spain, in 2006. Information on outcomes and covariates was obtained by questionnaire. We measured residential surrounding greenness as the average of satellite-derived Normalized Difference Vegetation Index (NDVI) in buffers of 100 m, 250 m, 500 m, and 1,000 m around each home address. Residential proximity to green spaces was defined as living within 300 m of a forest or a park, as separate variables. We used logistic regression models to estimate associations separately for each exposure–outcome pair, adjusted for relevant covariates. Results: An interquartile range increase in residential surrounding greenness was associated with 11–19% lower relative prevalence of overweight/obesity and excessive screen time, but was not associated with current asthma and allergic rhinoconjunctivitis. Similarly, residential proximity to forests was associated with 39% and 25% lower relative prevalence of excessive screen time and overweight/obesity, respectively, but was not associated with current asthma. In contrast, living close to parks was associated with a 60% higher relative prevalence of current asthma, but had only weak negative associations with obesity/overweight or excessive screen time. Conclusion: We observed two separable patterns of estimated health benefits and risks associated with different types of greenness