Strontium-90 activity in bones of the A-bomb exposed in Hiroshima and exhumed on Ninoshima island

Sr-90 activity was determined in the bone samples exhumed in 1955 and 1971 on Ninoshima, an island south of Hiroshima City. The bone samples were from those who died during approximately three weeks after exposure to the atomic bomb on August 6, 1945. Detectable concentrations up to 42 mBq (gCa)-1 were found in 3 femora, 3 tibiae, 3 humeri, 2 ribs and 4 vertebrae out of 21 samples analyzed. Distribution of 90Sr in the femur and tibia was examined. Although effects of exchange of this nuclide between bone and soil and loss of its activity by leaching are not well known, contamination due to the soil was estimated to be relatively small. From the results, possible existence of internally deposited 90Sr was suspected. (author)