The Biology of Bioavailability: The Role of Functional Ecology in Exposure Processes
ER-1750
Objective
Contaminant bioaccumulation through benthos to fish, wildlife, and humans is the exposure pathway responsible for the risks driving most cleanup decisions for contaminated sediments at Department of Defense (DoD) sites. Improved approaches for quantifying contaminant bioavailability and exposures within the sediment bed are key to reducing uncertainties in descriptions of risks to benthos and fish that feed on benthos. More accurate exposure characterizations are also necessary to support the challenges of designing, implementing, and monitoring the performance of cost-effective in situ remedies for contaminated sediments. Approaches that explicitly consider the functional ecology of the diverse array of species comprising benthos will produce more accurate and certain exposure assessments and predictions for remedial decision making.
The objective of this project is to increase the accuracy of exposure assessments for contaminated sediment by developing a more complete understanding of exposure variation among benthic species that is caused by functional differences in how organisms interact with sediment particles, pore water, and overlying water.
Technical Approach
Benthic species vary in terms of their position within the sediment column (shallow versus deep), their relation to sediment particles and pore water (tube building versus free burrowing), and feeding behavior (filter feeding versus deposit feeding), all of which contribute to differences in contaminant exposure and the notion of contaminant bioavailability. Manipulative experiments conducted during the course of this project will result in a quantitative understanding that relates the functional ecology of a receptor with its realized exposure. This understanding will be incorporated into improved exposure models, which will provide for more credible risk assessments and better predictions about remedy performance.
Benefits
This project will reduce the uncertainty associated with current exposure assessments and predictions that are used in remedy selection and design. This outcome will reduce the need for using conservative safety factors in calculating exposure point estimates and will provide a mechanistic basis for designing in situ remedies that are targeted to reduce exposures to benthos and fish that consume benthos. Incorporating the predictive algorithms within RECOVERY, which is used to evaluate in situ remedies, will greatly facilitate technology infusion. (Anticipated Project Completion - 2013)
Points of Contact
Principal Investigator
Dr. Todd Bridges
U.S. Army Engineer Research and Development Center (ERDC)
Phone: 601-634-3626
Fax: 601-634-3528
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.