Cesium-137 Concentration in Human Urine and Estimation of Cesium-137 Body Burden Due to World-wide Fallout

抄録

To evaluate hazards of environmental contamination due to fission products from nuclear weapon test explosions, determination of body burden of the radionuclides taken in human body is essential. Because urine analysis is one of the practical methods to estimate body burden, Cs-137 concentration in human urine has been surveyed in Osaka and Ishikawa Prefectures since the fall of 1959. From the results of analyses, time variation of Cs-137 concentration and difference between two sampling sites were discussed with respect to the fallout rate. Cs-137 body burden was estimated from the analytical results by assuming the exponential equation for continuous exposure : In November 1959 the values were 8.4 mμc in Ishikawa and 6.0 mμc in Osaka respectively. And they decreased to 3 mμc in October 1961 in both areas. These values were consistent with the results obtained by other methods. Cs-137 gonad dose could be calculated with these values assuming uniform distribution of Cs-137 in a human body. Gonad dose rate due to internally deposited Cs-137 at present is about 0.7 mrad/y, and gonad dose up to the present is in the range of 5 to 8 mrad.