Evolving Science and Practice of Risk Assessment

Abstract

Managing public health risks from environmental contaminants has historically relied on a risk assessment process defined by the regulatory context in which these risks are assessed. Risk assessment guidance follows a straightforward, chemical‐by‐chemical approach to inform regulatory decisions around the question “what is the risk‐based concentration protective of human and ecological health outcomes?” Here we briefly summarize regulatory risk assessment in the context of innovative risk assessment approaches based on an evolving understanding of the underlying scientific disciplines that support risk analysis more broadly. We discuss scientific versus regulatory tensions in the application of these approaches for future risk assessments, and challenges in translating our improved understanding of the underlying scientific complexity to the regulatory landscape to better inform decision making that extends beyond conventional regulatory mandates.

A Systematic Framework for Collecting Site-Specific Sampling and Survey Data to Support Analyses of Health Impacts from Land-Based Pollution in Low- and Middle-Income Countries

“…The state of the science continues to evolve and is moving at a faster pace than regulatory guidelines developed to evaluate public health risks [ 13 ]. For example, biomonitoring is a rapidly expanding field with improvements in molecular techniques leading to the identification of novel biomarkers, including oncogenes, tumor suppressor genes, microRNAs and long non-coding RNAs, DNA methylation and others [ 97 , 98 , 99 , 100 , 101 ].…”

“…CSMs describe qualitative linkages between contaminant sources and releases and exposures and health outcomes in a population (i.e., source to receptor) by showing how contaminants of concern (CoCs) that are released or discharged from specific activities can migrate through the environment, and the pathways and routes by which individuals in the population can be exposed to those contaminants and experience subsequent health effects [ 13 , 14 , 17 ]. The CSM captures essential relationships across key components of the analyses and provides a roadmap for quantifying these relationships based on the data collection efforts that are the focus of the systematic framework.…”

“…While environmental monitoring provides data on exposure concentrations, household surveys provide information on intake rates and exposure factors, which, when combined, can be used to quantify potential exposure pathways and routes in a population [ 13 , 14 ]. On the other hand, biomonitoring data provides a measure of internal dose of a contaminant or its metabolite from all sources and exposure pathways [ 25 , 26 , 27 ].…”

“…Risk assessment approaches can be used to predict the likelihood of adverse health effects based on measured or modeled exposure concentrations and exposure factors combined with toxicity data [ 13 ]. However, these methods lack a direct linkage to measurable health outcomes in communities and typically rely on animal toxicity data and uncertainty or “safety” factors that do not reflect the complexity or level of actual environmental exposures or population susceptibilities, particularly among populations facing multiple co-morbidities [ 14 ].…”

Toward Property-Based Regulation

“…It is also supported by the elucidation that fundamental chemical properties determine the inherent hazard of a chemical, − which enables a path to hazard prediction across distinct chemical classes. Notably, while the US EPA conducts extensive SAR modeling using chemical analogs to evaluate the potential exposure and toxicity concerns for new chemicals submitted for premanufacture review and approval, limited precedent exists for regulating classes of chemicals . The United States Food and Drug Administration’s recent regulatory action on per- and polyfluoroalkyl substances (PFAS), however, moves from a chemical-by-chemical approach toward class-based (or property-based) regulation, where groups of chemicals can be identified as sharing properties and risks and are thus evaluated and regulated together .…”