Contaminant exposure and sublethal effects in a piscivorous seabird
Robinson, Gabrielle Leigh
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We measured mercury and polychlorinated biphenyls (PCBs) in least terns (Sternula antillarum) across coastal Georgia to determine concentrations and sublethal effects. We are the first to document the transport of Aroclor 1268, a PCB mixture that was released exclusively at the Linden Chemical Plant (LCP) Superfund site in Brunswick, GA, at least 70 km south and 110 km north of its point source. Mean mercury in chick feathers and sediment, as well as egg Aroclor 1268 concentrations, were highest at sites closest to LCP. Mercury exposure was associated with biomarkers of both developmental instability and immunosuppression. Primary feather and wing chord symmetry in chicks both decreased with increasing primary feather mercury concentration. Heterophil/lymphocyte ratios in chick blood decreased with increasing fecal mercury. Increased prevalence (2.9%, n =7) of teratogenic deformities in the Savannah River least tern colony was also associated with elevated mercury. We also found that predator management substantially increased least tern nest success.