THE DISTRIBUTION AND BEHAVIOR OF ARTIFICIAL RADIONUCLIDES IN SEDIMENTS OF THE NORTH WALES COAST, UK

The distribution of Cs-134, Cs-137 and Am-214 in surface and core sedi ments from areas in north Wales has been investigated. Coastal sites s how a predominance of Sellafield-derived material for all three radion uclides whereas estuarine sites show an increased proportion of Cherno byl-derived caesium present. By the use of the Cs-134/Cs-137 ratio, a mean proportion of Chernobyl-derived Cs-137 in surface sediments colle cted in 1991 fell from 34% at an estuarine site to 11% al a coastal si te. In deeper sections of cores representing sedimentation dales near the Chernobyl accident, up to 90% of Cs-137 at the estuarine site and 26% at the coastal sire can be attributed to Chernobyl. By using the p osition of the Chernobyl Cs-134 and Cs-137 peak in the cores, sediment ation rates of 0.7 mm . a(-1) were calculated.