Trihalomethanes in Drinking Water and Bladder Cancer Burden in the European Union

Abstract

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 lg=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.

Identifying Novel Causes of Cancers to Enhance Cancer Prevention: New Strategies Are Needed

“…Much concern has been raised about the possible carcinogenic effect of environmental factors occurring at low levels although in a ubiquitous fashion across populations. Examples include nutritional contaminants such as pesticides, low-level electromagnetic radiation, or water pollutants such as trihalomethanes or per- and polyfluoroalkyl substances ( 41 , 42 ). Accurate measurements over the life course is challenging for such exposures.…”

Potential spreading risks and disinfection challenges of medical wastewater by the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA in septic tanks of Fangcang Hospital

“…More than 600 kinds of DBPs have been observed (Richardson, 2011), such as trihalomethanes (THMs), haloacetic acids (HAAs), halogen acetonitriles (HANs), halonitromethanes (HNMs) and haloacetamides (HAcAms) (Ding et al, 2020;Kozari et al, 2020;Luo et al, 2020;Zhai et al, 2014). Some of them are reported attributable for bladder cancer (Evlampidou et al, 2020;Li and Mitch, 2018) and adverse reproductive outcomes (Nieuwenhuijsen et al, 2000). For effective centralized disinfection, World Health Organization (WHO) has suggested free chlorine ≥0.5 mg/L after at least 30 min of contact time at pHb8.0 (WHO, 2020b).…”

Association of blood trihalomethane concentrations with asthma in US adolescents: nationally representative cross-sectional study

“…The drinking water concentrations of TTHMs (median 25.3 μg·L −1 ) in the NHANES population were among the medium environmental exposure levels measured in previous studies from the UK (mean 26.5 μg·L −1 ), Spain (median 23.5 μg·L −1 ), Italy (median 1.5 μg·L −1 ), Greece (mean 29.8 μg·L −1 ) and China (median 10.53 μg·L −1 ) [ 37 , 38 ]. In this study, the excess risk of asthma due to high blood DBCM and Br-THM concentrations and tobacco smoke exposure was higher than the summed risk associated with each individual factor, suggesting that the previously well-established associations of tobacco smoke exposure with asthma could be further exacerbated by high blood BDCM and DBCM concentrations.…”