A LABORATORY-STUDY AND FIELD-STUDY OF PO-210 DEPURATION BY EDIBLE WINKLES (LITTORINA-LITTOREA L) FROM THE CUMBRIAN COAST (NORTH-EASTERN IRISH SEA)

Edible winkles from Saltom Bay, Cumbria (north-eastern Irish Sea) had flesh Po-210 concentrations in excess of 200 Bq kg(-1) (wet). This cam e from liquid waste discharged under authorization from a chemical pla nt producing phosphoric acid. This labelling of the winkles under natu ral conditions was exploited to determine the Po-210 depuration rate a nd biological halftime. Winkles transferred to Lowestoft and depurated in flowing seawater had biological half-times ranging from 82 to 119 days depending on temperature. These values seem long from the few dat a available in the literature. Cadmium was also discharged in the liqu id waste and cadmium was measured in the depurating winkles, The hypot hesis is put forward that tire long half-times were due Po-210 binding to sob-cellular proteins induced by the presence of cadmium. After th e chemical plant was shut, changes in Saltom Bag winkle flesh contents of Po-210, Pb-210 and cadmium were followed by monthly samples. The b iological half-time in the environment for the decrease in Po-210 afte r the plant closed was estimated at about 92 days.