Weight-of-evidence prioritization of contaminants detected in the Milwaukee Estuary Area of Concern

Full title: Weight-of-evidence prioritization of organic contaminants detected in the Milwaukee Estuary Area of Concern (Milwaukee, WI)

Presented on April 27, 2021, by Erin Maloney - Postdoctoral Associate at University of Minnesota Duluth / US EPA - at the 2021 Emerging Contaminants in the Environment Conference

Abstract: Anthropogenic activities including industrialization, urbanization, and agriculture have resulted in frequent detection of contaminants/mixtures across Great Lakes tributaries. Thus, there is a need to identify CECs of high and low ecotoxicological concern to help focus risk assessment and regulatory efforts. Here we present a weight-of-evidence framework developed to prioritize organic contaminants detected within the Milwaukee Estuary Area of Concern (AOC) (Milwaukee, WI). Chemical prioritization was carried out using experimental data (in vivo, in vitro, and analytical data) generated from 2017-2018 caged-fish studies, and chemical-specific data collated from USEPA databases (CompTox Chemicals Dashboard, ECOTOXicology Knowledgebase, ToxCast database) or estimated using quantitative structure-activity relationships. Overall prioritization was based on multiple lines of evidence: detection characteristics (spatial frequency, temporal frequency, environmental distribution), environmental fate (persistence, bioaccumulation, biomagnification), ecotoxicological potential (water quality, in vivo, and in vitro toxicity benchmarks), and effect covariance (covariance with effects in caged fish studies). Results indicated within the Milwaukee AOC, 19/83 detected CECs were high priority, 13/83 were low priority, and 19/83 were data limited, requiring further investigation for prioritization efforts. Overall, this study presents an effects-based weight-of-evidence strategy that can be employed for CEC prioritization, and highlights several chemicals of ecotoxicological interest within the Milwaukee Estuary AOC.