Guidelines for Selecting the Appropriate Bioaccumulation Model(s) for Nonionic Organic Contaminants When Assessing Risk and Remedial Effectiveness at Contaminated Sediment Sites
The U.S. EPA’s Ecological Risk Assessment Support Center (ERASC) within the Office of Research and Development has prepared guidelines providing 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.
This guidelines document assists site managers and environmental scientists to consistently select the optimum model(s) for bioaccumulation-related applications (e.g., assess risk and remedial effectiveness) at their contaminated sediment sites. The objectives of this document are to provide an overview of bioaccumulation models for nonionic hydrophobic organic contaminants (NOCs), and the parameters that should be considered when selecting bioaccumulation models for use in assessing risk or remedial effectiveness at contaminated sediment sites. However, selecting which bioaccumulation model to use at a specific site is not trivial and involves balancing several critical parameters including:
This guidelines document assists site managers and environmental scientists to consistently select the optimum model(s) for bioaccumulation-related applications (e.g., assess risk and remedial effectiveness) at their contaminated sediment sites. The objectives of this document are to provide an overview of bioaccumulation models for nonionic hydrophobic organic contaminants (NOCs), and the parameters that should be considered when selecting bioaccumulation models for use in assessing risk or remedial effectiveness at contaminated sediment sites. However, selecting which bioaccumulation model to use at a specific site is not trivial and involves balancing several critical parameters including:
- the objectives of the study, as well as which contaminants are being investigated and the purpose of the decision being made based on the modeled estimate, which will influence the level of accuracy and precision needed for the estimate(s) generated by the model.
- the type of data available or site-specific data which can be collected, and
- the resources available for applying a given model (i.e., level of effort, funding) to make an estimate.
Background
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), use of passive sampling polymers to estimate freely dissolved concentrations (Cfree) of contaminants and 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 accessible for applying a given model.Impact/Purpose
The use of bioaccumulation models at contaminated sediment sites is an important approach for making scientifically informed decisions; however, guidelines for selecting which type of model to use has been limited. As a result, ERASC was requested by Region 4 to provide guidelines for selecting the appropriate bioaccumulation model(s) to apply at contaminated sediment sites to successively assess risk and remedial effectiveness.Status
This is the final report.Citation
U.S. EPA. Guidelines for Selecting the Appropriate Bioaccumulation Model(s) for Nonionic Organic Contaminants When Assessing Risk and Remedial Effectiveness at Contaminated Sediment Sites. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-24/086, 2024.History/Chronology
| Date | Description |
|---|---|
| 01- Aug 2024 | EPA published the final report incorporating the external peer review comments. |
| 02- May 2024 | Reviews were completed and comments were addressed to produce the external review draft, Guidelines for Selecting the Appropriate Bioaccumulation Model(s) for Nonionic Organic Contaminants when Assessing Risk and Remedial Effectiveness at Contaminated Sediment Sites. |
| 03- Feb 2024 | An internal review draft was completed. |
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This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.