Environmental Contaminants in Tern Eggs from Monomoy National Wildlife Refuge and Seal Island National Wildlife Refuge
Steven E. Mierzykowski
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Six non-viable common tern (Sterna hirundo) and three roseate tern (Sterna dougallii) eggs were collected from Monomoy National Wildlife Refuge (NWR) in Massachusetts and Seal Island NWR in Maine. Eggs were formed into three 3-egg species-specific composites – one common tern sample and one roseate tern sample from Monomoy NWR, and one common tern sample from Seal Island NWR. All composite samples were analyzed for 26 organochlorine compounds and 19 trace elements. At Monomoy NWR, Total Polychlorinated Biphenyl (PCB) concentrations in common tern and roseate tern composite egg samples were 0.67 and 1.13 µg/g, fresh wet weight, respectively. Total PCB in the common tern composite egg sample from Seal Island NWR was 0.34 µg/g. DDE, a metabolite of the pesticide DDT, was found at 0.03 µg/g in both the common and roseate tern samples from Monomoy NWR, and at 0.05 µg/g in the common tern sample from Seal Island NWR. Concentrations of Total PCB and DDE were below suggested toxic effect threshold levels. Twenty-four other organochlorine compounds were below detection limits or in the low ng/g (ppb) range. Mercury was detected at 0.14 µg/g and 0.11 µg/g in roseate tern and common tern egg samples from Monomoy NWR, respectively. At Seal Island NWR, the common tern egg composite sample had a mercury concentration of 0.09 µg/g. Concentrations in all three samples were well below a suggested avian reproductive effect threshold for mercury (0.80 µg/g). Of the eighteen other trace elements in the analytical scan, ten were below detection in all samples. Although detected in all samples, levels of arsenic, copper, iron, magnesium, manganese, selenium, strontium, and zinc were not elevated compared to other regional tern studies and to suggested threshold effect levels.
U.S. Fish and Wildlife Service
http://www.fws.gov/northeast/mainecontaminants/pdf/Monomoy_Seal_Final_Report.pdf, 2 MB
Maine Field Office Environmental Contaminants Program