title: The radiation exposure of black-headed gulls (Larus ridibundus) in the Ravenglass Estuary, Cumbria, U.K.: a preliminary assessment.
abstract: A variety of fission-product and transuranic radionuclides originating from the marine discharges from the fuel reprocessing plant at Sellafield, Cumbria are detectable in the bodies of black-headed gulls and their environment in the Ravenglass Estuary approximately 10 km to the south-west of the plant. The maximum concentrations of 95Nb, 137Cs and 239/240Pu detected in body tissues lie in the range 2 X 10(-3) to 1.5 X 10(-2) Bqg-1 wet weight. Many more radionuclides are detected in the regurgitated pellets and faeces produced by the gulls and have higher concentrations in the range 7 X 10(-3) to 1.7 Bqg-1 wet weight. The radionuclide contamination of the sediment produces a source of enhanced external gamma-ray exposure which can be measured directly. The available data on distributions and concentrations of radionuclides have been combined with simple dosimetry models to provide estimates of the radiation exposure of the birds. The total whole body dose rate to the adult birds from the contaminant radionuclides is approximately ten times that from the natural radiation background, while that to the developing eggs is approximately four times the natural background. The potential radiation exposure of the cells lining the alimentary tract could be much higher when contaminated food is in transit, but the long-term average exposure in this case is subject to uncertainty. The limited data on the effects of radiation exposure on birds do not indicate any response at dose rates below one hundred times that from the natural radiation background.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001717:Birds; D004739:England; D004781:Environmental Exposure; D005243:Feces / Q000032:analysis; D005260:Female; D011868:Radioisotopes / Q000032:analysis*; D014873:Water Pollutants; D014875:Water Pollutants, Radioactive
chemical_list: D011868:Radioisotopes; D014873:Water Pollutants; D014875:Water Pollutants, Radioactive