Assessing the human health impacts of exposure to disinfection by-products — A critical review of concepts and methods

Abstract

Understanding the public health implications of chemical contamination of drinking water is important for societies and their decision-makers. The possible population health impacts associated with exposure to disinfection by-products (DBPs) are of particular interest due to their potential carcinogenicity and their widespread occurrence as a result of treatments employed to control waterborne infectious disease. We searched the literature for studies that have attempted quantitatively to assess population health impacts and health risks associated with exposure to DBPs in drinking water. We summarised and evaluated these assessments in terms of their objectives, methods, treatment of uncertainties, and interpretation and communication of results. In total we identified 40 studies matching our search criteria. The vast majority of studies presented estimates of generic cancer and non-cancer risks based on toxicological data and methods that were designed with regulatory, health-protective purposes in mind, and therefore presented imprecise and biased estimates of health impacts. Many studies insufficiently addressed the numerous challenges to DBP risk assessment, failing to evaluate the evidence for a causal relationship, not appropriately addressing the complex nature of DBP occurrence as a mixture of chemicals, not adequately characterising exposure in space and time, not defining specific health outcomes, not accounting for characteristics of target populations, and not balancing potential risks of DBPs against the health benefits related with drinking water disinfection. Uncertainties were often poorly explained or insufficiently accounted for, and important limitations of data and methods frequently not discussed. Grave conceptual and methodological limitations in study design, as well as erroneous use of available dose-response data, seriously impede the extent to which many of these assessments contribute to understanding the public health implications of exposure to DBPs. In some cases, assessment results may cause unwarranted alarm among the public and potentially lead to poor decisions being made in sourcing, treatment, and provision of drinking water. We recommend that the assessment of public health impacts of DBPs should be viewed as a means of answering real world policy questions relating to drinking water quality, including microbial contaminants; that they should be conducted using the most appropriate and up-to-date data and methods, and that associated uncertainties and limitations should be accounted for using quantitative methods where appropriate.

Inactivation of pathogenic microorganisms in freshwater using HSO5−/UV-A LED and HSO5−/Mn+/UV-A LED oxidation processes

“…DBPs are associated with public health risks via ingestion, inhalation, and skin absorption (Doederer et al, 2014). The majority of DBPs are a consequence of the chlorination of naturally occurring organic precursors such as humic substances (WHO, 2008;Grellier et al, 2015). Consequently, finding alternative effective mean of water disinfection which simultaneously avoid the generation of disinfection by-products has attracted the attention of many investigators (Venieri et al, 2015;Ferro et al, 2015;Giannakis et al, 2015).…”

Do disinfection byproducts in drinking water have an effect on human cancer risk worldwide? A meta‐analysis

“…Evidence shows that THMs are the most common DBPs, and they are 6,000 times more toxic than other DBPs (McDonald & Komulainen, ; Richardson, Plewa, Wagner, Schoeny, & DeMarini, ). Several epidemiological studies have been carried out on the association of DBPs in drinking water with various human cancers (Bull et al., ; Grellier, Rushton, Briggs, & Nieuwenhuijsen, ; Hrudey et al., ; King, Marrett, & Woolcott, ; Nieuwenhuijsen et al., ). Among the various types of reported cancers, kidney, lung, rectal, colon, esophageal, breast, pancreatic, urinary bladder, brain, leukemia, and melanoma are the cancers reported at the highest frequencies (Siegel et al., ; Torre et al., ).…”

Validação de método analítico por ELL-CG-EM para detecção de trialometanos decorrentes da cloração de águas contendo Microcystis

“…Os limites em águas para fins de abastecimento público variam em cada país: União Europeia (100 μg.L -1 ), França (100 μg.L -1 ), Estados Unidos (80 μg.L -1 ), Brasil (100 μg.L -1 ) e Canadá (100 μg.L -1 ) (COMUNIDAD EUROPEA, 1998;USEPA, 1998;BRASIL, 2017a;HEALTH CANADA, 2017), sendo o triclorometano (TCM), o bromodiclorometano (BDCM), o dibromoclorometano (DBCM) e o tribromometano (TBM) os de monitoramento exigido nos mencionados padrões de potabilidade. Os TAM são substâncias classificadas pelas agências internacionais como agentes carcinogênicos em seres humanos, o que torna extremamente relevante a realização de trabalhos de avaliação de risco (LEGAY et al, 2010;FLORENTIN;HAUTEMANIÈRE;HARTEMANN, 2011;USEPA, 2012;GRELLIER et al, 2015). Outros SOH potencialmente prejudiciais à saúde humana decorrentes da cloração da água também são relatados na literatura, como os ácidos haloacéticos (AHA), os haloaldeídos (HAD), as halocetonas (HK), os halofenóis (HF), as halopicrinas (HP) e o tricloronitrometano (TCNM) (LEGAY et al, 2010;BUTIÃO, 2011;GAN et al, 2013;CARDADOR;SALGUERO;GALLEGO, 2015).…”