Tc-99 concentrations in soils collected in Japan, Chernobyl and Dolon

Technetium-99 (Tc-99) is a pure beta emitter (Emax=0.29keV) and its radiological half-life is 2.11 x 105 y. It is produced in the fissions of U-235 and Pu-239 at relatively high ratios of ca. 6%, which is similar to the values for Cs-137 and Sr-90. Tc-99 is widely distributed in the environment as a result of fallout from nuclear weapons testing and discharges from nuclear facilities. Tc is thought to be highly soluble and rarely adsorbed onto soil, however, its mobility under natural environment is not well known because its scarcity and low levels in environmental samples has limited the available data. In this study, therefore we determined the concentrations of Tc-99 in soil samples collected in agricultural fields in Japan, three forests near the Chernobyl (the Federal Office for Radiation Protection, Germany, assisted by Moscow State University, Russia, and the Research and Industrial Association \u27Pripyat\u27, Ukraine), and samples collected at Dolon (provided by Dr. Imanaka, Kyoto University, and Dr. Hoshi, Hiroshima University) to understand the distribution.14th Hiroshima International Symposium -Semipalatinsk and related studies