Formatted Title:

Guidelines for Selecting Bioaccumulation Models for Nonionic Organic Contaminants When Assessing Risk at Contaminated Sediment Sites

Background/Objectives:

Over the last 30 years, several models have been developed to predict bioaccumulation for assessing and managing the risks associated with contaminated sediment sites. These models include simple ratios of biota to sediment concentrations (i.e., biota-sediment accumulation factor [BSAF]), use of passive sampling polymers as a surrogate for organism lipid, and complex food web models that consider metabolic biotransformation and excretion as well as spatial and/or temporal changes. Bioaccumulation models have many applications including: (i) predicting concentrations of contaminants in organisms from concentrations in environmental media, (ii) developing site-specific conceptual models and risk assessments, (iii) back-calculating risk-based sediment remedial goals, and (iv) predicting past or future tissue concentrations before or after remediation. However, selecting which bioaccumulation model to use at a given site involves balancing several critical decision considerations including (1) investigation objectives such as which contaminants are being monitored and the nature of the decision being made, (2) the level of accuracy and precision needed for the modelled estimate(s), (3) the types of data available, and (4) resources available for applying a given model.

Approach/Activities:

The U.S. Environmental Protection Agency has developed guidelines that provide an overview of bioaccumulation models for nonionic organic contaminants and an approach for selecting the appropriate bioaccumulation model(s) for use at contaminated sediment sites. The document consists of the following primary sections: Consideration of Equilibrium and Steady State Conditions in Bioaccumulation Models, Bioaccumulation Models – Categories, Considerations and Assumptions, Case Studies and Examples, and Important Principles and Considerations in the Selection of Bioaccumulation Models.

Results/Lessons Learned:

This presentation and the document it describes will assist site managers and environmental scientists to consistently select the optimum model(s) for bioaccumulation-related applications at their contaminated sediment sites. The document is available at the following U.S. EPA website: https://www.epa.gov/land-research/ecological-risk-assessment-support-center-erasc.

Michael Kravitz

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(Group 1, Poster Board #20) Guidelines for Selecting Bioaccumulation Models for Nonionic Organic Contaminants When Assessing Risk at Contaminated Sediment Sites