Modeling DDE and PCB bioaccumulation in marine mammals and birds of the California Channel Islands
- HydroQual, Inc., Mahwah, NJ (United States)
An area of sediment on the Palos Verdes Shelf off Los Angeles, CA is contaminated with DDE and PCBs as a result of discharges since the 1950s. Elevated concentrations of these contaminants have been found in fish living in the vicinity of the sediment, as well as in birds and California sea lions from the Channel Islands, some of which are located more than 100 km from the contaminated sediments. It was the purpose of this study to determine if the contamination in the Channel Island animals was derived from the Palos Verdes sediments. This was necessary in order to estimate the improvement to be expected should the sediment contamination decline through natural processes or remediation efforts. Time variable, age dependent, physiologically-based toxicokinetic models of California sea lions, bald eagles, peregrine falcons and double-crested cormorants were developed. Mass and energy balance equations describe the uptake and loss of contaminants. The contaminants are pardoned among multiple body compartments, including lipid and non-lipid body tissue, and, for female sea lions, milk. Contaminants are distributed into a fetus or eggs of females. Physiological and toxicokinetic data were used to establish rates of growth, respiration and reproduction, internal partitioning of DDE and PCBs, efficiencies of DDE and PCB uptake and rates of DDE and PCB excretion. Field-measured dietary composition and prey contaminant levels were used to calculate potential exposure to DDE and PCBs. The models were then used to evaluate whether the animals could have obtained their contaminant burdens from prey not impacted by the Palos Verdes sediment plume. In all cases, background contaminant levels were insufficient and association with the more highly contaminated prey of the Southern California Bight was the probable source.
- OSTI ID:
- 197567
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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