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LINKING EFFECTS OF PERSISTENT BIOACCUMULATIVE TOXICANTS TO CHEMICAL EXPOSURES IN AQUATIC ECOSYSTEMS
Citation:
Burkhard, L P., B C. Butterworth, P. M. Cook, J D. Fernandez, AND M. K. Lukasewycz. LINKING EFFECTS OF PERSISTENT BIOACCUMULATIVE TOXICANTS TO CHEMICAL EXPOSURES IN AQUATIC ECOSYSTEMS. Presented at Eighteenth Annual Sigma Xi-Duluth Scientific Poster Exhibit, Atrium of University of Minnesota, Duluth, MN, February 18, 2002.
Description:
The critical step in characterization of ecological risks associated with exposures of fish and wildlife to persistent bioaccumulative toxicants (PBTs) is linking chemical residue based toxicological data to concentrations of PBTs in sediments, water, and biota. This is necessary in order to determine unsafe chemical loading rates to aquatic ecosystems. Bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) relate concentrations in biota associated with toxicity to concentrations in water and sediments, respectively. Using a hybrid food chain bioaccumulation modeling approach, we have identified five parameters as the primary determinants of BAFs and BSAFs. These are the ecosystem related conditions: food web composition (%benthic/pelagic), trophic level of the organism, and sediment-water column chemical concentration quotient and two key chemical properties: hydrophobicity (octanol-water partition coefficient) and degree/rate of metabolism.
Our on-going research involves high resolution gas chromatography/high resolution mass spectrometry analysis of Lake Michigan food web, sediment, and water samples to create a high quality bioaccumulation data set for advancing a variety of bioaccumulation prediction models. In addition to establishing a high quality reference set of BAFs and BSAFs for PBTs, we are attempting to measure rates of metabolism which are required for improvement of food chain models. The approach involves accounting for the metabolism effect on bioaccumulation differences between unmetabolized chemicals. The ultimate objective is to advance the capability for using chemical residue based toxicology data in probabilistic risk-based assessments of chemical loading conditions.
This abstract does not necessarily reflect EPA policy.