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THE RELATIONSHIP OF BIOACCUMULATIVE CHEMICALS IN WATER AND SEDIMENT TO CHEMICAL RESIDUES IN FISH: A VISUALIZATION APPROACH
Citation:
Burkhard, L P., D. R. Mount, AND P. M. Cook. THE RELATIONSHIP OF BIOACCUMULATIVE CHEMICALS IN WATER AND SEDIMENT TO CHEMICAL RESIDUES IN FISH: A VISUALIZATION APPROACH. Presented at Ecological Risk Assessment Forum Meeting, Washington, DC, January 31, 2003.
Description:
An approach to viewing and evaluating bioaccumulation data by using water-sediment chemical concentration (XY) plots will be presented. One of the difficulties for those outside of the detailed study of PBTs is the relative importance and interrelationships among variables influencing the bioaccumulation of chemicals in aquatic organisms. The visualization approach captures and illustrates the relative importance and interrelationships using XY plots where the X-axis is the chemical concentration in water and the Y-axis is the chemical concentration in sediment. For any specific ecosystem, the chemical concentrations in the water and sediment define the bioaccumulation relationships, i.e., BAFs and BSAFs. The approach is based on five basic parameters that affect bioaccumulation of nonionic organic chemicals: 1) the distribution of chemical between sediment and water, 2) the hydrophobicity of the compound (expressed as the n-octanol/water partition coefficient, Kow), 3) the relationship of food chains to water and sediment, 4) the length of the food chains, and 5) the degree to which the chemical is metabolized.
The visualization approach serves two purposes. First, to teach those not intimately familiar with bioaccumulation processes the important parameters and their interrelationships upon the bioaccumulation occurring in aquatic food web. Second, for any chemical for any site, a bioaccumulation (XY) plot can be developed, and with the plot, appropriate "What if?" questions can be developed to assess the relative importance of the individual uncertainties associated with the data used in developing the plot. For example, what if the diet of the piscivorous fish in your ecosystem is poorly understood; i.e., the percentage of different forage fish consumed by the piscivorous fish. With the bioaccumulation (XY) plots, one could explore the effects of the differing diets by evaluating diets consisting of purely one species of forage fish for the piscivorous fish; one evaluation for each forage fish species. Plotting of the results from the different diets on the bioaccumulation (XY) plots would define the range of possible BAFs and BSAFs for the site, and would enable an appropriate evaluation of the importance of this individual uncertainty for the ecologicial risk assessment.