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Extrapolation of Biota-sediment Accumulation Factors
Citation:
BURKHARD, L. P., P. M. COOK, AND M. T. LUKASEWYCZ. Extrapolation of Biota-sediment Accumulation Factors. Presented at Battelle Fifth International Conference on Remediation of Contaminated Sediments, Jacksonville, FL, February 02 - 05, 2009.
Impact/Purpose:
By performing some type of extrapolation where BSAFs are ultimately derived for the species and location of interest from existing BSAF data, one can address the data limitations when assessing risks at sites with contaminated sediments.
Description:
When assessing risks at sites with contaminated sediments, risk assessors need to estimate residues in fish and other aquatic biota based upon the levels of contaminants in the sediments. Unfortunately, risk assessors are often challenged by data limitations, i.e., i) contaminant data for the sediments only (i.e., no contaminant data for biota), ii) incomplete data such that biota-sediment accumulation factors (BSAFs) can not be developed because of temporal and/or spatial differences between the sediment and tissue data, and iii) BSAF data limited to select locations and/or species for a site. One approach to address these limitations is to perform some type of extrapolation where BSAFs are ultimately derived for the species and location of interest from existing BSAF data. Using a data set of approximately 18,000 BSAFs, techniques for extrapolating BSAF data across locations, species, and/or sites are evaluated. The extrapolation techniques evaluated range from direct application of measured BSAFs to other locations and/or species to application of measured BSAFs with adjustments for differences like trophic level, sediment-water chemical disequilibria, and diet between the location and species of the measured BSAFs and the location and species of interest. Preliminary results suggest extrapolations can be performed with relatively small differences. For example, if one applies measured BSAFs from one location within a site for a specific species to other locations within the site for that species, the median differences between the estimated and actual BSAFs are 2.6 for fish, 2.8 for mussel, and 3.7 for decapoda (e.g., lobster, crayfish, shrimp, and blue crab) species groups. A series of data limited situations commonly faced by risk assessors and other users of BSAF data will be covered in the presentation.