Advancing exposure assessment approaches to improve wildlife risk assessment.

The exposure assessment component of a Wildlife Ecological Risk Assessment involves estimating or measuring the magnitude, frequency, and duration of exposure to a chemical or environmental contaminant, along with characteristics of the exposed population. This can be challenging in wildlife as there is often high uncertainty and bias caused by broad-based interspecific extrapolation and assumptions often because of a lack of data. Both the United States Environmental Protection Agency (US EPA) and European Food Safety Authority (EFSA) have broadly directed exposure assessments to include estimates of the quantity (dose or concentration), frequency and duration of exposure to a contaminant of interest while considering "all relevant factors". This ambiguity in the inclusion or exclusion of specific factors (e.g., individual and species-specific biology, proportion time in treated or contaminated area) can significantly influence the overall risk characterization. In this review, we identify four major categories of complexity that should comprise an exposure assessment - chemical, environmental, organismal and ecological. These may require more data, but a degree of inclusion at all stages of the risk assessment is critical to moving beyond screening-level methods that have a high degree of uncertainty and suffer from conservatism and a lack of realism. We demonstrate that there are many existing and emerging scientific tools and cross-cutting solutions for tackling exposure complexity. To foster greater application of these methods into wildlife exposure assessments, we present a new framework for risk assessors to construct an "exposure matrix". Using three case studies, we illustrate how the matrix can better inform, integrate, and more transparently communicate, the important elements of complexity and realism in exposure assessments for wildlife. Modernizing wildlife exposure assessments is long overdue and will require improved collaboration, data sharing, application of standardized exposure scenarios, better communication of assumptions and uncertainty, and post regulatory tracking. This article is protected by copyright. All rights reserved. Integr Environ Assess Manag 2023;00:0-0. © 2023 SETAC.