PO-210 AND PB-210 IN EDIBLE MOLLUSKS FROM NEAR THE CAPE-OF-GOOD-HOPE - SOURCES OF VARIABILITY IN PO-210 CONCENTRATIONS

Measurements of the natural radionuclides Po-210 and Pb-210 in mussels, squid and oysters from near the Cape of Good Hope are reported and compared with previously published Po-210 and Pb-210 data from Northern Hemisphere organisms in the same taxa. Emphasis is laid on discussing the causes of variability in the concentrations of Po-210 in marine organisms. No systematic evidence is found for a 'latitude' effect, but allometric effects, intertaxon differences, change of diet with animal size and regional effects are all significant for Po-210. The consequences for human radiation dose calculations of variability of Po-210 levels in seafoods are discussed briefly; particular reference is made to the case of a Stone Age mussel-eating community in South Africa.