Vertical profiles of Iodine-131 and Cesium-137 in soils in Fukushima Prefecture related to the Fukushima Daiichi Nuclear Power Station Accident

Vertical profiles of iodine-131 and cesium-137 emitted from the Fukushima Daiichi Nuclear Power Station were determined in soil core samples collected in Fukushima prefecture. The profiles showed that more than 76% of the radionuclides were retained within 5 cm of the surface. Leaching experiments showed that cesium was strongly bound to soil particles which could not be leached with 2 M HCl, while more than 40% of iodine was incorporated into humic substances.