The Weight‐of‐Evidence Approach and the Need for Greater International Acceptance of Its Use in Tackling Questions of Chemical Harm to the Environment

Abstract

As we attempt to manage chemicals in the environment we need to be sure that our research efforts are being directed at the substances of greatest threat. All too often we focus on a chemical of concern and then cast around for evidence of its effects in an unstructured way. Risk assessment based on laboratory ecotoxicity studies, combined with field chemical measurements, can only take us so far. Uncertainty about the range and sufficiency of evidence required to take restorative action often puts policymakers in a difficult situation. We review this conundrum and reflect on how the “Hill criteria,” used widely by epidemiologists, have been applied to a weight‐of‐evidence approach (a term sometimes used interchangeably with ecoepidemiology) to build a case for causation. While using a set of such criteria to address sites of local environmental distress has been embraced by the US Environmental Protection Agency, we urge a wider adoption of weight‐of‐evidence approaches by policymakers, regulators, and scientists worldwide. A simplified series of criteria is offered. Progress will require a sustained commitment to long‐term wildlife and chemical monitoring over a sufficient geographic spread. Development of a comprehensive monitoring network, coupled with assembling evidence of harm in a structured manner, should be the foundation for protecting our ecosystems and human health. This will enable us to not only judge the success or failure of our efforts but also diagnose underlying causes. Environ Toxicol Chem 2021;40:2968–2977. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Renewing and Improving the Environmental Risk Assessment of Chemicals

“…Finally, a word of caution is probably appropriate. Any new ERA process is unlikely to be perfect, just as the current process isn't (Johnson et al, 2021). One issue that could be particularly problematic is the toxicity not of the parent chemicals, but of any transformation products formed from them in the environment.…”

“…There is now a widespread view that the current processes involved in the regulation of chemicals may be insufficiently protective of the environment, and hence they need to be improved (reviewed in Johnson et al, 2021;Wang et al, 2021). Yet, surprisingly, relatively little appears to have been written in the open scientific literature on how the current ERA process could be improved (some suggestions on specific aspects of the ERA can be found in, for example, Kortenkamp and Faust, 2018;LaLone et al, 2021;Syberg and Hansen, 2016;van Dijk et al, 2021).…”

Study of the Pollution Generated by Wastewater from the Refining of Vegetable Oils

“…Due to the toxicity of phenolic pollutants and detergents used in developing countries, industrial units increasingly use high-performance techniques to comply with Moroccan legislation, including the optimal consumption of these products, awareness, prevention, and wastewater treatment. In addition, the increase in the consumption of detergents (often nonbiodegradable) by the population and the industrial environment poses serious environmental problems and challenges [17,19,58]. Moreover, phenols and detergents significantly impact humans in the short and long term [13,59].…”

Environmental Assessors Should Use State‐of‐Practice Weight‐of‐Evidence Processes

“…As a longtime proponent of inference by weight of evidence (WoE), I was pleased to see the ET&C paper by Johnson et al (2021) advocating for WoE. I was also pleased to see the acknowledgment of my work on WoE, particularly at the US Environmental Protection Agency (USEPA) with Susan Cormier and Sue Norton.…”