Search

Background: Trihalomethanes (THMs) are widespread disinfection by-products (DBPs) in drinking water, and long-term exposure has been consistently associated with increased bladder cancer risk., Objective: We assessed THM levels in drinking water in the European Union as a marker of DBP exposure and estimated the attributable burden of bladder cancer., Methods: We collected recent annual mean THM levels in municipal drinking water in 28 European countries (EU28) from routine monitoring records. We estimated a linear exposure-response function for average residential THM levels and bladder cancer by pooling data from studies included in the largest international pooled analysis published to date in order to estimate odds ratios (ORs) for bladder cancer associated with the mean THM level in each country (relative to no exposure), population-attributable fraction (PAF), and number of attributable bladder cancer cases in different scenarios using incidence rates and population from the Global Burden of Disease study of 2016., Results: We obtained 2005-2018 THM data from EU26, covering 75% of the population. Data coverage and accuracy were heterogeneous among countries. The estimated population-weighted mean THM level was 11.7 μ g / L [standard deviation (SD) of 11.2]. The estimated bladder cancer PAF was 4.9% [95% confidence interval (CI): 2.5, 7.1] overall (range: 0-23%), accounting for 6,561 (95% CI: 3,389, 9,537) bladder cancer cases per year. Denmark and the Netherlands had the lowest PAF (0.0% each), while Cyprus (23.2%), Malta (17.9%), and Ireland (17.2%) had the highest among EU26. In the scenario where no country would exceed the current EU mean, 2,868 (95% CI: 1,522, 4,060; 43%) annual attributable bladder cancer cases could potentially be avoided., Discussion: Efforts have been made to reduce THM levels in the European Union. However, assuming a causal association, current levels in certain countries still could lead to a considerable burden of bladder cancer that could potentially be avoided by optimizing water treatment, disinfection, and distribution practices, among other possible measures. https://doi.org/10.1289/EHP4495.

Background: Evidence on the association between colorectal cancer and exposure to disinfection by-products in drinking water is inconsistent., Objectives: We assessed long-term exposure to trihalomethanes (THMs), the most prevalent group of chlorination by-products, to evaluate the association with colorectal cancer., Methods: A multicenter case-control study was conducted in Spain and Italy in 2008-2013. Hospital-based incident cases and population-based (Spain) and hospital-based (Italy) controls were interviewed to ascertain residential histories, type of water consumed in each residence, frequency and duration of showering/bathing, and major recognized risk factors for colorectal cancer. We estimated adjusted odds ratios (OR) for colorectal cancer in association with quartiles of estimated average lifetime THM concentrations in each participant's residential tap water (micrograms/liter; from age 18 to 2 years before the interview) and estimated average lifetime THM ingestion from drinking residential tap water (micrograms/day)., Results: We analyzed 2,047 cases and 3,718 controls. Median values (ranges) for average lifetime residential tap water concentrations of total THMs, chloroform, and brominated THMs were 30 (0-174), 17 (0-63), and 9 (0-145) μg/L, respectively. Total THM concentration in residential tap water was not associated with colorectal cancer (OR = 0.92, 95% CI: 0.66, 1.28 for highest vs. lowest quartile), but chloroform concentrations were inversely associated (OR = 0.31, 95% CI: 0.24, 0.41 for highest vs. lowest quartile). Brominated THM concentrations showed a positive association among men in the highest versus the lowest quartile (OR = 1.43, 95% CI: 0.83, 2.46). Patterns of association were similar for estimated average THM ingestion through residential water consumption., Conclusions: We did not find clear evidence of an association between detailed estimates of lifetime total THM exposure and colorectal cancer in our large case-control study population. Negative associations with chloroform concentrations and ingestion suggest differences among specific THMs, but these findings should be confirmed in other study populations. Citation: Villanueva CM, Gracia-Lavedan E, Bosetti C, Righi E, Molina AJ, Martín V, Boldo E, Aragonés N, Perez-Gomez B, Pollan M, Gomez Acebo I, Altzibar JM, Jiménez Zabala A, Ardanaz E, Peiró R, Tardón A, Chirlaque MD, Tavani A, Polesel J, Serraino D, Pisa F, Castaño-Vinyals G, Espinosa A, Espejo-Herrera N, Palau M, Moreno V, La Vecchia C, Aggazzotti G, Nieuwenhuijsen MJ, Kogevinas M. 2017. Colorectal cancer and long-term exposure to trihalomethanes in drinking water: a multicenter case---control study in Spain and Italy. Environ Health Perspect 125:56-65; http://dx.doi.org/10.1289/EHP155., Competing Interests: The authors declare they have no actual or potential competing financial interests.

There appears to be very good epidemiological evidence for a relationship between chlorination by-products, as measured by trihalomethanes (THMs), in drinking water and bladder cancer, but the evidence for other cancers, including colorectal cancer appears to be inconclusive and inconsistent. There appears to be some evidence for a relationship between chlorination by-products, as measured by THMs, and small for gestational age (SGA)/intrauterine growth retardation (IUGR) and preterm delivery, but evidence for other outcomes such as low birth weight (LBW), stillbirth, congenital anomalies and semen quality appears to be inconclusive and inconsistent.The overall aim of the HIWATE study is to investigate potential human health risks (e.g. bladder and colorectal cancer, premature births, SGA, semen quality, stillbirth, congenital anomalies) associated with long-term exposure to low levels of disinfectants (such as chlorine) and DBPs occurring in water for human consumption and use in the food industry. The study will comprise risk-benefit analyses including quantitative assessments of risk associated with microbial contamination of drinking water versus chemical risk and will compare alternative treatment options. The outcome will be improved risk assessment and better information for risk management. The work is divided into different topics (exposure assessment, epidemiology, risk assessment and management) and studies.

A few epidemiologic studies have suggested that consumption of drinking water with high trihalomethane content increases the risk of cancer. We investigated the mortality of a cohort of 5144 residents in Guastalla, northern Italy, who were supplied tap water with high chloroform and trihalomethane content between 1965 and 1987. Using death rates of a nearby community as reference rates, the standardized mortality ratio from all cancers between 1987 and 1999 was slightly increased for both males (1.2, 95% confidence interval 1.1-1.4) and females (1.1, 95% confidence interval 1.0-1.3). This was mainly due to a higher mortality from stomach, liver, lung, prostate and bladder cancer in males and from stomach, pancreas, breast and ovarian cancer and lymphocytic leukemia in females. We also noted excess mortality from melanoma in both males and females. Overall, our findings were consistent with an association between trihalomethane exposure and increased cancer risk at some sites. However, the point estimates were statistically imprecise, due to the limited number of deaths for some site-specific cancers. In addition, we were unable to rule out the possibility of confounding due to smoking and other life-style factors with regard to some of the excess rates.

Subjects attending indoor swimming pools are exposed to disinfection by-products (DBPs) by inhalation, dermal contact and/or ingestion, as a consequence of water disinfection treatments with chlorine and related compounds. The occurrence of trihalomethanes (THMs) in pool waters has been well documented, while information about other DBPs, including bromate, chlorite, chlorate and haloacetic acids (HAAs), is very limited even though some of these substances are potentially dangerous for human health. The aim of this study was to investigate the occurrence of bromate, chlorite, chlorate, HAAs and THMs both in pool and in source water of 24 public indoor swimming pools in Emilia Romagna Region, Northern Italy. THMs were evaluated with a standardized method involving the head-space gas-chromatographic technique, while HAAs, bromate, chlorite, and chlorate were detected by Ion Chromatography with Mass Spectrometry. THMs were measured in all the pool water samples (mean value: 36.9±28.2μg/l), while they were detectable in less than 50% of source waters and always at very low levels (mean value: 2.0±4.1μg/l), as a consequence of drinking water disinfection with chlorine dioxide, a widespread disinfection method in Italy. Bromate was always absent in source water samples, and it was detected in 3 samples of pool water only (range: 10–48μg/l). HAAs were scarcely detected in source waters (3 positive samples, maximum level observed: 21μg/l), while in pool water they were always present at detectable levels and showed high concentrations (range: 11–403μg/l, mean value of 164±108μg/l). Chlorite was present in 22 water supply samples (mean value: 149±122μg/l) but only in one pool water. Chlorate, on the contrary, resulted as the most prevalent DBP both in source (range: 2–499μg/l) and in pool waters, where it showed the highest levels, with a mean value of 3661μg/l and a maximum value of 19537μg/l. Such environmental levels could result in an important human exposure, mainly by ingestion and/or dermal contact, to non volatile DBPs different than THMs. Exposure to those DBPs, therefore, needs to be further investigated and strategies aimed at minimizing it should be identified and undertaken. Attention should be paid, above all, to chlorate: this substance appears really widespread in swimming pool water and, according to the most recent toxicological studies, its potential human health effects could be relevant. [ABSTRACT FROM AUTHOR]

Background: Epidemiological evidence of an association between disinfection by-products (DBPs) exposure via drinking water and reproductive outcomes is still inconclusive. Objective: The aim of this study was to investigate the association between trihalomethanes (THMs), chlorite and chlorate exposure and congenital anomalies. Methods: A case-control study was carried out in Emilia-Romagna Region (Italy). Data on 1917 different congenital anomalies (neural tube, cardiac, diaphragm and abdominal wall, oesophagus, cleft lip and palate, respiratory, urinary tract and chromosomal anomalies) observed in the period 2002–2005 were extracted from the Regional Malformation Registry. Four controls (newborns without anomalies) were randomly selected form the Regional Birth Register and frequency matched to cases according to pregnancy period. The network supplying water during the first trimester of pregnancy was identified on the basis of mother's address: DBPs data, technical and structural information were linked to each subject. Results: Overall, THMs exposure was very low (mean: 3.8±3.6μg/l), and no risk excess was observed. Chlorite and chlorate values were fairly high (mean: 427±184μg/l and 283±79μg/l, respectively). Women exposed to chlorite level >700μg/l were at higher risk of newborns with renal defects (OR: 3.30; 95% IC: 1.35–8.09), abdominal wall defects (OR: 6.88; 95% IC: 1.67–28.33) and cleft palate (OR: 4.1; 95% IC: 0.98–16.8); women exposed to chlorate level >200μg/l were at higher risk of newborns with obstructive urinary defects (OR: 2.88; 95% IC: 1.09–7.63), cleft palate (OR: 9.60; 95% IC:1.04–88.9) and spina bifida (OR: 4.94; 95% IC:1.10–22). Conclusions: This was the first study showing an excess risk of different congenital anomalies related to chlorite and chlorate exposure via drinking water: further research is needed to confirm the observed relationships in large datasets, specifically for chlorate, an unregulated DBP. [Copyright &y& Elsevier]