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Organochlorine Contaminants in blubber samples from stranded marine mammals collected from the Oregon and Washington coasts; implications for re-introducing California condors in Oregon

16 November 2010


The re-introduction of California condors into Oregon is currently being considered, but there are concerns about the safety of the potential food sources of this species. Condors are opportunistic feeders and a largely available food source for this species will be the carcasses of stranded marine mammals. Organochlorine contaminants are of particular concern due to the life history and trophic status of most marine species found stranded on local beaches in Oregon and Washington. The objectives of this study was to monitor blubber samples from stranded marine mammals off of the Oregon and Washington coasts for 18 chlorinated pesticides, and 16 PCB congeners (PCB Group 1a, 1b, and 2), measured using GC-ECD, to determine if consumption of the carcasses pose a potential risk for re-introduced condors. In addition, this study will evaluate if any relationship exists between pesticide levels in mammal blubber samples and some of the post-mortem parameters recorded for each specimen (length, blubber thickness, the presence of disease, and sex). We analyzed multiple blubber samples from 7 different marine mammal species (California sea lions n = 6, harbor seals n = 3, Steller sea lions n = 6, harbor porpoises n = 3), collected from the Oregon and Southern Washington coasts. We also looked at single blubber samples from a sperm whale, elephant seal, and Dall's porpoise. DDE was the most prevalent organochlorine contaminant making up more than 77% of the total organochlorine concentration measured. Mean DDE concentrations ranged from 3.58 + 1.36 ppm for harbor seals to 12.00 + 12.00 ppm for California sea lions (lipid weight). Total PCBs ranged from 2.44 + 3.39 ppm for Stellar sea lions to 12.79 + 8.29 ppm for harbor porpoises (lipid weight). Implication for raptors feeding on these contaminated carcasses and potential health effects of these contaminants on the beached mammals are discussed.


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