Organochlorine concentrations in prefledging common terns Sterna hirundo at three Rhode Island USA colonies

Concentrations of DDE, polychlorinated biphenyls (PCBs), and polychlorinated diphenyl ethers (PCDPEs) in carcasses of prefledging Common Terns (Sterna hirundo) at three Rhode Island colonies support the hypothesis that local contamination is responsible for among-colony differences observed in eggs in an earlier study. The highest concentrations of DDE and PCBs (mean=0.24 and 2.8 ppm wet weight) were found in prefledging terns from Providence, a highly industrialized area, and the lowest (DDE range=nd-0.11, PCBs mean=0.85) in terns from Price Neck, an undeveloped area 40 km to the south, PCDPEs were detected in 3 of 14 tern carcasses from Providence and were not detected in carcasses from 2 other colonies. The occurrence and concentrations of DDE and PCBs in killifish (Fundulus spp.), a major dietary item of Common Terns, qualitatively demonstrated the same trend among locations.