Organochlorine Pesticides and Polychlorinated Biphenyls in American Oystercatchers Nesting along the Texas Gulf Coast

The American Oystercatcher (Haematopus palliatus palliatus) is an important breeding species along the Texas Gulf Coast, particularly between Galveston Bay and Corpus Christi, Texas, USA. American Oystercatchers are considered a species of greatest conservation need and are on the priority list for conservation by the National Fish and Wildlife Foundation. American Oystercatchers feed mainly on oysters (Ostreidae) and other bivalves, which are known to accumulate significant amounts of pollutants. We determined accumulation and potential effects of environmental contaminants, particularly organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) in blood of American Oystercatchers nesting along the Texas Gulf Coast, USA during 2012 and 2013. Plasma concentrations of OCs and PCBs were low. The most commonly detected OC pesticides were HCB, HCH, alpha chlordane, endosulfan, methoxychlor, p,p'-DDD, and p,p'-DDE. Total p,p'-DDE concentrations ranged from 2-10 ng/mL ww and total PCB concentrations ranged from 2-54 ng/mL ww. Mean p,p'-DDE concentrations were similar among regions; however, total PCBs were significantly greater (P = 0.0056) in blood from adult birds from West Galveston Bay, Texas, USA in 2013 than in blood from young collected in 2012, mostly also from West Galveston Bay. Overall, concentrations of OC pesticides in plasma were low; however, some PCB concentrations were above the NOAEC levels that have been associated with normal reproduction in other bird species.