Distribution of Cs-137 and inventories of Pu-238, Pu-239/240, Am-241 and Cs-137 in Irish Sea intertidal sediments

Estimated total inventories of 41 TBq Cs-137, 19 TBq Am-241, 13 TBq Pu-239/ 240 and ? TBq Pu-238 were calculated for the intertidal sediments of the ea stern Irish Sea to a depth of 50 cm. These estimates should be more accurat e than previous inventory figures since they are based on a much greater nu mber of observations: most earlier estimates were based on extrapolation fr om analysis of small numbers of samples. However, they will almost certainl y be underestimates, by up to an order of magnitude, since full account has not been taken of the vertical distribution of radionudides in the sedimen ts and because there are almost certainly significant quantities of radionu clides at depths greater than 50 cm. The inventories were obtained from fie ld and laboratory studies of the distribution of gamma-emitting radionuclid es (principally Cs-137) in the sediments with data for the actinides being derived by establishing their relationships to Cs-137 through analysis of s ediment samples by gamma and alpha spectrometry. (C) 1999 Natural Environme nt Research Council. Published by Elsevier Science Ltd. All rights reserved .