Magnesium in drinking water and liver cancer morbidity--a possible relation?

The paper presents results of a research on liver cancer morbidity in Opole province, Poland, in relation to magnesium exposure in drinking water. Based on the extensive empirical materials of cancer registry information and water quality, the well known statistical approach using BUGS software was applied in the study. The results support a hypothesis of a possible association between the deficiency of magnesium in drinking water and the increase of liver cancer morbidity in the population exposed. The outcomes were presented in a table and graphically in histograms, scatterplots and maps.     

Does perchlorate in drinking water affect thyroid function in newborns or school-age children?

Perchlorate is known to suppress thyroid function by inhibiting uptake of iodide by the human thyroid at doses of 200 mg/day or greater. A study was conducted to investigate the potential effects of perchlorate in drinking water on thyroid function in newborns and school-age children. A total of 162 school-age children and 9784 newborns were studied in three proximate cities in northern Chile that have different concentrations of perchlorate in drinking water: Taltal (100 to 120 micrograms/L), Cha?aral (5 to 7 micrograms/L), and Antofagasta (non-detectable: < 4 micrograms/L). Among schoolchildren, no difference was found in thyroid-stimulating hormone levels or goiter prevalence among lifelong residents of Taltal or Cha?aral compared with those of Antofagasta, after adjusting for age, sex, and urinary iodine. No presumptive cases of congenital hypothyroidism were detected in Taltal or Cha?aral; seven cases were detected in Antofagasta. Neonatal thyroid-stimulating hormone levels were significantly lower in Taltal compared with Antofagasta; this is opposite to the known pharmacological effect of perchlorate, and the magnitude of difference did not seem to be clinically significant. These findings do not support the hypothesis that perchlorate in drinking water at concentrations as high as 100 to 120 micrograms/L suppresses thyroid function in newborns or school-age children.     

Drug residues and endocrine disruptors in drinking water: risk for humans?

The presence of pharmaceuticals and endocrine disruptors in the environment raises many questions about risk to the environment and human health. Environmental exposure has been largely studied, providing to date a realistic picture of the degree of contamination of the environment by pharmaceuticals and hormones. Conversely, little information is available regarding human exposure. NSAIDS, carbamazepine, iodinated contrast media, β-blockers, antibiotics have been detected in drinking water, mostly in the range of ng/L. it is questioned if such concentrations may affect human health. Currently, no consensus among the scientific community exists on what risk, if any, pharmaceuticals and endocrine disruptors pose to human health. Future European research will focus, on one hand, on genotoxic and cytotoxic anti-cancer drugs and, on the other hand, on the induction of genetic resistance by antibiotics. This review does not aim to give a comprehensive overview of human health risk of drug residues and endocrine disruptors in drinking water but rather highlight important topics of discussion.     

Cancer incidence and pattern of arsenic concentration in drinking water wells in Córdoba, Argentina

Cancer occurrence is associated with Arsenic (As) in drinking water. In Argentina, there are high As concentrations in groundwater but there is no published evidence yet of an association between geographic patterns of cancer incidence and the distribution of As in groundwater supplies. The purpose of this study is to assess the association between cancer incidence patterns and As in Córdoba province's aquifers. Age standardized incidence rates (ASIRs) were obtained from Córdoba Cancer Registry (CCR), and As data from official reports of monitoring wells. A multilevel model was applied. Total ASIRs by aquifers for males/females were 191.01/249.22 (Rioja plain); 215.03/225.37 (Pampa hills); and 239.42/188.93 (Chaco-Pampa plain). As was associated with increased risk of colon cancer in women, and lung and bladder cancers in both sexes. It had no association with breast cancer. ASIRs were related to As, controlling for unobserved heterogeneity. An overlapping pattern of higher As and higher risks was evident for lung, bladder and female colon cancers.     

Occurrence of perfluorinated compounds (PFCs) in drinking water of North Rhine-Westphalia,Germany and new approach to assess drinking water contamination by shorter-chained C4–C7 PFCs

After detection of perfluorooctanoate (PFOA) in drinking water at concentrations up to 0.64 μg/l in Arnsberg, Sauerland, Germany, the German Drinking Water Commission (TWK) assessed perfluorinated compounds (PFCs) in drinking water and set for the first time worldwide in June 2006 a health-based guide value for safe lifelong exposure at 0.3 μg/l (sum of PFOA and perfluorooctanesulfonate, PFOS). PFOA and PFOS can be effectively removed from drinking water by percolation over granular activated carbon. Additionally, recent EU-regulations require phasing out use of PFOS and ask to voluntarily reduce the one of PFOA. New and shorter-chained PFCs (C4–C7) and their mixtures are being introduced as replacements. We assume that some of these “new” compounds could be main contributors to total PFC levels in drinking water in future, especially since short-chained PFCs are difficult to remove from drinking water by common treatment techniques and also by filtration over activated carbon. The aims of the study were to summarize the data from the regularly measured PFC levels in drinking water and in the drinking water resources in North Rhine-Westphalia (NRW) for the sampling period 2008–2009, to give an overview on the general approach to assess PFC mixtures and to assess short-chained PFCs by using toxicokinetic instead of (sub)chronic data. No general increase of substitutes for PFOS and PFOA in wastewater and surface water was detected. Present findings of short-chained PFC in drinking waters in NRW were due to extended analysis and caused by other impacts. Additionally, several PFC contamination incidents in drinking water resources (groundwater and rivers) have been reported in NRW. The new approach to assess short-chained PFCs is based on a ranking of their estimated half-lives for elimination from the human body. Accordingly, we consider the following provisional health-related indication values (HRIV) as safe in drinking water for lifelong exposure: perfluorobutanoate (PFBA) 7 μg/l, perfluoropentanoate (PFPA) 3 μg/l, perfluorohexanoate (PFHxA) 1 μg/l, perfluoroheptanoate (PFHpA) 0.3 μg/l, perfluorobutanesulfonate (PFBS) 3 μg/l, perfluoropentanesulfonate (PFPS) 1 μg/l, perfluorohexanesulfonate (PFHxS) 0.3 μg/l and perfluoroheptanesulfonate (PFHpS) 0.3 μg/l. For all PFCs the long-term lowest maximal quality goal (general precautionary value, PV_g) in drinking water is set to −0.1 μg/l.     

How well does a telephone questionnaire measure drinking water intake?

BACKGROUND: Few studies have assessed the validity or reliability of drinking water intake estimations. In studies investigating potential waterborne disease, this is very important. METHODS: We carried out a validity and reliability study to evaluate water intake estimations. The validity part of the study compared a telephone questionnaire to a diary. The reliability part of the study compared two telephone questionnaires. RESULTS: 253 participants were recruited. The most commonly consumed water intake categories were plain and boiled tap water. For persons aged less than 12 years, the median volume of plain water consumption was 2.9 glasses/day according to the diary. For persons aged 12 years and over, the median volume of plain water consumption was 3.0 glasses/day and for boiled water 3.0 glasses/day according to the diary. There was negligible systematic over or under reporting by participants for the telephone questionnaire in comparison to the diary and for the comparison of both telephone questionnaires. Water intake estimates were converted to categorical variables and the per cent agreement and weighted kappa statistics were calculated. For both the validity and reliability parts of the study the per cent agreement was 57-78% and the weighted kappa was 0.57-0.81. CONCLUSION: Water intake estimates show only moderate levels of validity and reliability when using a telephone questionnaire in comparison to a diary. IMPLICATIONS: Investigators of potential waterborne disease or nutritional research should exercise some caution in drawing conclusions from minor differences in drinking water intake that are obtained from a telephone questionnaire.     

A critical evaluation of two point-of-use water treatment technologies: can they provide water that meets WHO drinking water guidelines?

Point-of-use (POU) technologies have been proposed as solutions for meeting the Millennium Development Goal (MDG) for safe water. They reduce the risk of contamination between the water source and the home, by providing treatment at the household level. This study examined two POU technologies commonly used around the world: BioSand and ceramic filters. While the health benefits in terms of diarrhoeal disease reduction have been fairly well documented for both technologies, little research has focused on the ability of these technologies to treat other contaminants that pose health concerns, including the potential for formation of contaminants as a result of POU treatment. These technologies have not been rigorously tested to see if they meet World Health Organization (WHO) drinking water guidelines. A study was developed to evaluate POU BioSand and ceramic filters in terms of microbiological and chemical quality of the treated water. The following parameters were monitored on filters in rural Cambodia over a six-month period: iron, manganese, fluoride, nitrate, nitrite and Escherichia coli. The results revealed that these technologies are not capable of consistently meeting all of the WHO drinking water guidelines for these parameters.     

Does ozonation of drinking water reduce the risk of bladder cancer?

BACKGROUND: Epidemiologic studies of drinking water disinfection byproducts have focused primarily on the carcinogenic potential of chlorination byproducts. Because drinking water has been ozonated in France for decades, we were able to assess the carcinogenic risk of the disinfection byproducts generated by both ozonation and chlorination. METHODS: We used data from a case-control study of bladder cancer conducted between 1985 and 1987 in 7 French hospitals. We compared 281 cases and 272 controls for whom we could reconstruct at least 70% of the residential exposure to drinking water contaminants over a 30-year period. RESULTS: When we took potential confounders and exposure to chlorination byproducts into account, the risk of bladder cancer decreased as duration of exposure to ozonated water increased (OR = 0.60 [95% CI = 0.3-1.3] for 1-9 years; OR = 0.31 [0.1-0.7] for 10 years or more). Simultaneously, the risk of bladder cancer increased with duration of exposure to chlorinated surface water and with the estimated trihalomethane content of the water. Our data suggest that ozonation reduces the risk associated with the chlorination of surface water and that ozonation alone could have an independent beneficial effect on bladder cancer risk. CONCLUSIONS: Our results are consistent with experimental evidence that ozonation in combination with chlorination decreases the concentration of trihalomethane in treated water and eliminates some of the mutagenicity of raw water.     

Detection of Helicobacter pylori in drinking water treatment plants in Bogotá, Colombia,using cultural and molecular techniques

Helicobacter pylori is one of the most common causes of chronic bacterial infection in humans, and a predisposing factor for peptic ulcer and gastric cancer. The infection has been consistently associated with lack of access to clean water and proper sanitation. H. pylori has been detected in surface water, wastewater and drinking water. However, its ability to survive in an infectious state in the environment is hindered because it rapidly loses its cultivability. The aim of this study was to determine the presence of cultivable and therefore viable H. pylori in influent and effluent water from drinking water treatment plants (DWTP). A total of 310 influent and effluent water samples were collected from three drinking water treatment plants located at Bogotá city, Colombia. Specific detection of H. pylori was achieved by culture, qPCR and FISH techniques. Fifty-six positive H. pylori cultures were obtained from the water samples. Characteristic colonies were covered by the growth of a large number of other bacteria present in the water samples, making isolation difficult to perform. Thus, the mixed cultures were submitted to Fluorescent in situ Hybridization (FISH) and qPCR analysis, followed by sequencing of the amplicons for confirmation. By qPCR, 77 water samples, both from the influent and the effluent, were positive for the presence of H. pylori. The results of our study demonstrate that viable H. pylori cells were present in both, influent and effluent water samples obtained from drinking water treatment plants in Bogotá and provide further evidence that contaminated water may act as a transmission vehicle for H. pylori. Moreover, FISH and qPCR methods result rapid and specific techniques to identify H. pylori from complex environmental samples such as influent water.     

How can the UK statutory Cryptosporidium monitoring be used for Quantitative Risk Assessment of Cryptosporidium in drinking water?

Quantitative Microbiological Risk Assessment (QMRA) is increasingly being used to complement traditional verification of drinking water safety through the absence of indicator bacteria. However, the full benefit of QMRA is often not achieved because of a lack of appropriate data on the fate and behaviour of pathogens. In the UK, statutory monitoring for Cryptosporidium has provided a unique dataset of pathogens directly measured in large volumes of treated drinking water. Using this data a QMRA was performed to determine the benefits and limitations of such state-of-the-art monitoring for risk assessment. Estimates of the risk of infection at the 216 assessed treatment sites ranged from 10(-6.5) to 10(-2.5) person(-1) d(-1). In addition, Cryptosporidium monitoring data in source water was collected at eight treatment sites to determine how Cryptosporidium removal could be quantified for QMRA purposes. Cryptosporidium removal varied from 1.8 to 5.2 log units and appeared to be related to source water Cryptosporidium concentration. Application of general removal credits can either over- or underestimate Cryptosporidium removal by full-scale sedimentation and filtration. State-of-the-art pathogen monitoring can identify poorly performing systems, although it is ineffective to verify drinking water safety to the level of 10(-4) infections person(-1) yr(-1).     

Does the risk of childhood diabetes mellitus require revision of the guideline values for nitrate in drinking water?

In recent years, several studies have addressed a possible relationship between nitrate exposure and childhood type 1 insulin-dependent diabetes mellitus. The present ecologic study describes a possible relation between the incidence of type 1 diabetes and nitrate levels in drinking water in The Netherlands, and evaluates whether the World Health Organization and the European Commission standard for nitrate in drinking water (50 mg/L) is adequate to prevent risk of this disease. During 1993-1995 in The Netherlands, 1,104 cases of type 1 diabetes were diagnosed in children 0-14 years of age. We were able to use 1,064 of these cases in a total of 2,829,020 children in this analysis. We classified mean nitrate levels in drinking water in 3,932 postal code areas in The Netherlands in 1991-1995 into two exposure categories. One category was based on equal numbers of children exposed to different nitrate levels (0.25-2.08, 2.10-6.42, and 6.44-41.19 mg/L nitrate); the other was based on cut-off values of 10 and 25 mg/L nitrate. We determined standardized incidence ratios (SIRs) for type 1 diabetes in subgroups of the 2,829,020 children with respect to both nitrate exposure categories, sex, and age and as compared in univariate analysis using the chi-square test for trend. We compared the incidence rate ratios (IRRs) by multivariate analysis in a Poisson regression model. We found an effect of increasing age of the children on incidence of type 1 diabetes, but we did not find an effect of sex or of nitrate concentration in drinking water using the two exposure categories. For nitrate levels > 25 mg/L, an increased SIR and an increased IRR of 1.46 were observed; however, this increase was not statistically significant, probably because of the small number of cases (15 of 1,064). We concluded that there is no convincing evidence that nitrate in drinking water at current exposure levels is a risk factor for childhood type 1 diabetes mellitus in The Netherlands, although a threshold value > 25 mg/L for the occurrence of this disease can not be excluded.     

Does drinking really decrease in bad times?

This paper investigates the relationship between macroeconomic conditions and drinking using individual-level data from 1987 to 1999 interview years of the "behavioral risk factor surveillance system" (BRFSS). We confirm the procyclical variation in overall drinking identified in previous research using aggregate sales data and show that this largely results from changes in consumption by existing drinkers, rather than movements into or out of drinking. Moreover, the decrease occurring during bad economic times is concentrated among heavy consumers, with light drinking actually rising. We also find no evidence that the decline in overall alcohol use masks a rise for persons becoming unemployed during contractions. These results suggest that any stress-induced increases in drinking during bad economic times are more than offset by declines resulting from changes in economic factors such as lower incomes.     

Is fecal contamination of drinking water after collection associated with household water handling and hygiene practices? A study of urban slum households in Hyderabad, India

Water-borne illness, primarily caused by fecal contamination of drinking water, is a major health burden in the state of Andhra Pradesh, India. Currently drinking water is treated at the reservoir level and supplied on alternate days, necessitating storage in households for up to 48 hrs. We hypothesized that fecal contamination occurs principally during storage due to poor water handling. In this study we tested for coliform bacteria in water samples collected at distribution points as household storage containers were filled, and then tested containers in the same households 24-36 hours after collection. We also conducted an observational survey to make an assessment of water handling and hygiene. Ninety-two percent (47/51) of samples tested at supply points were adequately chlorinated and bacterial contamination was found in two samples with no residual chlorine. Samples collected from household storage containers showed an increase in contamination in 18/50 houses (36%). Households with contaminated stored samples did not show significant differences in demographics, water handling, hygiene practices, or sanitation. Nevertheless, the dramatic increase in contamination after collection indicates that until an uninterrupted water supply is possible, the point at which the biggest health impact can be made is at the household level.     

Is fecal contamination of drinking water after collection associated with household water handling and hygiene practices? A study of urban slum households in Hyderabad, India

Water-borne illness, primarily caused by fecal contamination of drinking water, is a major health burden in the state of Andhra Pradesh, India. Currently drinking water is treated at the reservoir level and supplied on alternate days, necessitating storage in households for up to 48 hrs. We hypothesized that fecal contamination occurs principally during storage due to poor water handling. In this study we tested for coliform bacteria in water samples collected at distribution points as household storage containers were filled, and then tested containers in the same households 24–36 hours after collection. We also conducted an observational survey to make an assessment of water handling and hygiene. Ninety-two percent (47/51) of samples tested at supply points were adequately chlorinated and bacterial contamination was found in two samples with no residual chlorine. Samples collected from household storage containers showed an increase in contamination in 18/50 houses (36%). Households with contaminated stored samples did not show significant differences in demographics, water handling, hygiene practices, or sanitation. Nevertheless, the dramatic increase in contamination after collection indicates that until an uninterrupted water supply is possible, the point at which the biggest health impact can be made is at the household level.     

Contents of radon 222Rn in drinking water of Sweradów Zdrój and Czerniawa Zdrój

Radon-222 concentration in surface water, wells and tap water in Swieradów Zdrój and in Czerniawa Zdrój has been quantitative determined. The measurements were performed using the alpha liquid scintillation counting method. Radon arithmetic mean for water of individual wells in Swieradów Zdrój was found to be 438.5 Bq/l within the range between 42 Bq/ and 1095 Bq/l. The appropriate mean value for water of individual wells Czerniawa Zdrój was 165 Bq/l within the range from 25.8 Bq/l and 402.4 Bq/l. Waterworks in Czerniawa Zdrój is supplied with the surface water in which the radon concentration is low (about 2 Bq/l). Water works in Swieradów Zdrój is supplied with the mixed water consisting from the surface water, which main characteristic is low radon concentration (below 11 Bq/l), and from artesian well and mine gallery water with the radon concentration from 321 Bq/l to 464 Bq/l in it. This water is mixed in various ratios and therefore the radon concentration in it was within 4 Bq/l and 79 Bq/l.     

Type of alcoholic beverage and high-risk drinking: how risky is beer drinking in Korea?

AIMS: To examine the association of beverage type with high-risk drinking in Korea. METHODS: Data were analysed from the Korea's 1997 behavioural risk factor surveillance system survey collected by a stratified random sampling method (n = 1045). After alcohol consumption per drinking day was categorized into three risk levels for short-term or 'acute' harm on the basis of the World Health Organization's guidelines, logistic regression analysis adjusting for socio-demographic factors was performed for each beverage type. RESULTS: Using beer drinkers as the reference, those who drank soju (the most widely consumed traditional beverage in Korea) showed an adjusted odds ratio (OR) of 3.62 [95% confidence interval (CI) = 2.28-5.76] for high and very high risk from drinking and those who drank spirits had adjusted OR of 10.65 (95%CI = 4.32-26.27). CONCLUSIONS: In Korea, unlike in many western countries, beer is not the highest risk beverage. The relatively high price of beer in Korea is likely to be one influence. It is concluded that country-specific differences are important in studies on associations between alcoholic beverage types and high risk drinking.     

A study of the association between children’s access to drinking water in primary schools and their fluid intake: can water be ‘cool’ in school?

BACKGROUND: Water is essential for health. The 'Water is Cool in School' campaign promoted improved drinking water access in UK schools. Implementation has been patchy, and impact has not been studied. The aim of this study is to determine whether fluid intake and frequency of toilet visits are associated with children's access to drinking water in the classroom. METHODS: A total of 145 schoolchildren in Year 2 (aged 6-7 years) and 153 in Year 5 (aged 9-10 years) classes were studied in six Southampton schools. Total fluid intake and toilet visits were recorded during one school day. Schools were recruited according to drinking policy: 'prohibited access' = water prohibited in classroom; 'limited access' = water allowed in classroom but not on the desk; and 'free access' = water bottle encouraged on the desk. Data were analysed on an intention-to-treat basis. RESULTS: In total, 120 children in prohibited access, 91 in limited access and 87 in free access settings were recruited. Total fluid intake was significantly higher in Year 2 free access schools (geometric mean 293, range 104-953 mL) compared with prohibited access schools (geometric mean 189, range 0-735 mL, P=0.046), in Year 5 free access schools (geometric mean 489, range 88-1200 mL) compared with prohibited access schools (geometric mean 206, range 0-953 mL, P=0.001), and in free access versus limited access schools (geometric mean 219, range 0-812 mL, P=0.003). A total of 81% and 80% of children in prohibited and limited access schools, respectively, consumed below the minimum recommended amount of total fluid at school, compared with 46.5% in the free access schools. In total, 34.6% of children did not use the toilets at all during the school day. There was no trend observed between water access and frequency of toilet visits (median of 1 trip for each group, P=0.605). CONCLUSION: Most children have an inadequate fluid intake in school. Free access to drinking water in class is associated with improved total fluid intake. Primary schools should promote water drinking in class.     

Invited commentary: biomarkers of exposure to drinking water disinfection by-products--are we ready yet?

Studies of the relation between exposure to drinking water disinfection by-products and pregnancy outcomes have been limited by the complexity of the exposure itself (consisting of hundreds of different chemicals), the diverse pathways contributing to exposure, and the difficulty in assessing behavioral determinants of exposure. Therefore, exposure biomarkers offer great promise of enhancing exposure assessment, the limiting factor in the quality and conclusiveness of epidemiologic studies. However, there are significant conceptual and logistical challenges in developing biomarkers for the various constituents of concern that are sensitive to typical variation in exposure, reflective of the time periods of interest, not susceptible to interference from exposures other than water, not subject to reverse causality by correlates of adverse pregnancy outcomes, reflective of the chemicals of interest, and feasible for large-scale epidemiologic studies. Urinary trichloroacetic acid has been the leading candidate exposure biomarker for over a decade, and the first attempt to incorporate it into an epidemiologic study (Am J Epidemiol. 2012;175(4):263-275) is notable-the considerable limitations notwithstanding. In future efforts, investigators need to combine biomarker development with substantive epidemiologic studies to improve on this initial effort and prepare for more definitive research.