Strontium-90 and cesium-137 in sea water from July, 1981, to January, 1982

Sea water was collected at fixed stations where the effect of terrestrial fresh water from rivers was expected to be negligibly small. Weather conditions were also considered, and the sampling was carried out after a few days in which rain did not fall. Attention was paid to avoid the contamination in sampling and storing. The sample was stored in 20 l polyethylene containers in the acidified state of pH lower than 3. 200 ml of sea water was also collected at the same stations for the determination of chlorinity. The radiochemical separation of strontium-90 and cesium-137 was performed, and the mounted precipitates were counted for activity using low background beta counters normally for 60 min. Net sample counting rates were corrected to obtain the content of strontium-90 and cesium-137 radioactivity per sample aliquot, and concentrations of these nuclides in the original sample were calculated. The maximum values obtained were 0.16 pCi/l of Sr-90 in Osaka-bay and 0.17 pCi/l of Cs-137 in Mutsu-bay in August, 1981. (Kako, I.)