Recommended updates to the USEPA Framework for Metals Risk Assessment: Aquatic ecosystems

• Published in: Integrated environmental assessment and management Vol. 20; no. 4; pp. 924 - 951
• Main Authors: Adams, William J., Garman, Emily R.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.07.2024
• Subjects: Aquatic ecosystems; Bioavailability; Biovailability; Chemistry; Ecosystem; Ecosystems; Environmental assessment; Environmental Impact Assessment; Environmental management; Environmental Monitoring - methods; Environmental risk; Freshwater; Freshwater ecosystems; Geologic Sediments - chemistry; Heavy metals; Human performance; Inland water environment; Integrated environmental assessment; Jurisdiction; Metal concentrations; Metal models; Metals; Metals - analysis; Metals - toxicity; Metals framework; Nickel; Rapid loss; Regression models; Risk assessment; Risk Assessment - methods; Sediment; Sediments; Toxicity; Toxicology; United States; United States Environmental Protection Agency; Water chemistry; Water Pollutants, Chemical - analysis; Water quality; United States; Metal models; Sediment; Metals framework; Biovailability; Rapid loss
• ISSN: 1551-3777; 1551-3793; 1551-3793
• DOI: 10.1002/ieam.4827

In 2007, the USEPA issued its “Framework for Metals Risk Assessment.” The framework provides technical guidance to risk assessors and regulators when performing human health and environmental risk assessments of metals. This article focuses on advances in the science including assessing bioavailability in aquatic ecosystems, short‐ and long‐term fate of metals in aquatic ecosystems, and advances in risk assessment of metals in sediments. Notable advances have occurred in the development of bioavailability models for assessing toxicity as a function of water chemistry in freshwater ecosystems. The biotic ligand model (BLM), the multiple linear regression model, and multimetal BLM now exist for most of the common mono‐ and divalent metals. Species sensitivity distributions for many metals exist, making it possible for many jurisdictions to develop or update their water quality criteria or guidelines. The understanding of the fate of metals in the environment has undergone significant scrutiny over the past 20 years. Transport and toxicity models have evolved including the Unit World Model allowing for estimation of concentrations of metals in various compartments as a function of loading and time. There has been significant focus on the transformation of metals in sediments into forms that are less bioavailable and on understanding conditions that result in resolubilization or redistribution of metals in and from sediments. Methods for spiking sediments have advanced such that the resulting chemistry in the laboratory mimics that in natural systems. Sediment bioavailability models are emerging including models that allow for prediction of toxicity in sediments for copper and nickel. Biodynamic models have been developed for several organisms and many metals. The models allow for estimates of transport of metals from sediments to organisms via their diet as well as their water exposure. All these advances expand the tool set available to risk assessors. Integr Environ Assess Manag 2024;20:924–951. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points Models for measuring bioavailability of common metals in freshwater on a chronic basis are now available. Multiple linear regression models for bioavailability assessment of metals in freshwater have become available. Tools to measure rate of loss of metals from the water column have been developed and are available for risk assessment and metal classification. Models to assess metal bioavailability in sediments are available for copper and nickel and are emerging for other metals.