Aspects of the uptake of radionuclides by sheep grazing on an estuarine saltmarsh. 2. Radionuclides in sheep tissues

The transfer 137Cs, 238Pu, 239/240Pu and 241Am to sheep which graze a saltmarsh in the Esk estuary, 7 km south of the sellafield reprocessing plant in west Cumbria (UK), has been estimated. The concentrations of gamma-emitting radionuclides and of 238Pu, 239/240Pu and 241Am were measured in liver, lung, muscle, kidney and bone from saltmarsh ewes and lambs. 137Cs concentrations in the soft tissues were similar in liver, lung and muscle but were consistently higher in kidney and much lower in bone. The highest concentration of the transuranics was found in liver. Transfer coefficients and concentration factors were calculated for both ewes and lambs. The concentration of 137Cs in the tissues of 5-month old lambs was higher than in those of their mothers. Therefore, a higher transfer coefficient was obtained for lamb muscle (1·8 × 10−1 d kg−1) than for ewe muscle (6·4 × 10−2 d kg−1). Concentration factors were consistently higher for 137Cs than for the transuranics.