Risk‐based approach in the revised European Union drinking water legislation: Opportunities for bioanalytical tools

Abstract

A plethora of in vitro bioassays are developed in the context of chemical risk assessment and clinical diagnostics to test effects on different biological processes. Such assays can also be implemented in effect-based monitoring (EBM) of (drinking) water quality alongside chemical analyses. Effects-based monitoring can provide insight into risks for the environment and human health associated with exposure to (unknown) complex, low-level mixtures of micropollutants, which fits in the risk-based approach that was recently introduced in the European Drinking Water Directive. Some challenges remain, in particular those related to selection and interpretation of bioassays. For water quality assessment, carcinogenesis, adverse effects on reproduction and development, effects on xenobiotic metabolism, modulation of hormone systems, DNA reactivity, and adaptive stress responses are considered the most relevant toxicological endpoints. An evaluation procedure of the applicability and performance of in vitro bioassays for water quality monitoring, based on existing information, has been developed, which can be expanded with guidelines for experimental evaluations. In addition, a methodology for the interpretation of in vitro monitoring data is required, because the sensitivity of specific in vitro bioassays in combination with sample concentration may lead to responses of chemicals (far) below exposure concentrations that are relevant for human health effects. Different approaches are proposed to derive effect-based trigger values (EBTs), including EBTs based on (1) relative ecotoxicity potency, (2) health-based threshold values for chronic exposure in humans and kinetics of reference chemicals, and (3) read-across from (drinking) water guideline values. Effects-based trigger values need to be chosen carefully in order to be sufficiently but not overly conservative to indicate potential health effects. Consensus on the crucial steps in the selection and interpretation of in vitro bioassay data will facilitate implementation and legal embedding in the context of water quality monitoring of such assays in EBM strategies. Integr Environ Assess Manag 2018;00:000-000. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

“…Both advancements in microbial analytical methods and a move towards risk-based methods (as opposed to the traditional travel time-based methods) in drinking water management require a closer integration of hydrology with hydrogeochemistry and microbiology (e.g. Mayer et al 2018, Dingemans et al 2019.…”

“…Second, new topics seem to emerge where hydrology can play a more important role such as contaminants of emerging concern, microbial pathogens, or, more generally, the topic of water and health (e.g. Mayer et al 2018, Dingemans et al 2019, as well as spatial problems such as the interaction of migration and water issues. Third, the questions are broadened in terms of their spatial scales.…”

Glass-bottled drinking water: a time capsule to study the historic presence of hazardous chemicals using effect-based methods

“…Current drinking water regulation regarding chemical contaminants is in most countries, including the European Union, based on defined maximum concentration levels of a very limited number of chemicals or groups of chemicals [2]. There is, however, a substantial body of scientific literature showing that these well-known environmental pollutants can only explain a relatively small proportion of the observed toxicity in water samples, especially for toxicity endpoints such as reactive toxicity, xenobiotic metabolism and oxidative stress [3][4][5][6][7]. For some of these endpoints, the well-known environmental pollutants can only explain as little as 0.1-5% of the observed toxicity, implying that up to 99.9% of the toxicity is caused by unknown chemicals or mixture effects [3,4].…”

Responsible Water Reuse Needs an Interdisciplinary Approach to Balance Risks and Benefits

“…It is expected that a risk-based monitoring workflow for water reuse for irrigation can be based on the available technologies currently in use for drinking water purposes [47,54]. These can be complemented with bioanalytical tools that give information on the integrated effect of mixtures of chemicals related to a specific health effect [55,56]. By referring to a list of EU legislations on microbial and chemical risks from which requirements and obligations are also to be taken into account, many additional water quality requirements are indirectly included in the proposed regulation.…”