Caesium out of the body relatively quickly in sweat and urine. The remaining 90% has a biological half-life between 50 and 150 days. Radiocaesium follows potassium and tends to accumulate in plant tissues, including fruits and vegetables. Plants vary widely in the absorption of caesium, sometimes displaying great resistance to it. It is also well-documented that mushrooms from contaminated forests accumulate radiocaesium (caesium-137) in the fungal sporocarps. Accumulation of caesium-137 in lakes has been a great concern after the Chernobyl disaster. Experiments with dogs showed that a single dose of 3.8 millicuries (140 MBq, 4.1 μg of caesium-137) per kilogram is
Radiation effects from the Fukushima Daiichi nuclear disaster from the Fukushima plant. Rain accumulated the caesium in the soil. Measured radioactivity per kilogram reached 250 becquerels in eastern Hokkaido, and 25 becquerels in the mountains of western Japan. According to the research group, these levels were not high enough to require decontamination. Professor Tetsuzo Yasunari of the University of Nagoya called for a national soil-testing program because of the nationwide spread of radioactive material, and suggested identified hotspots, places with high radiation levels, should be marked with warning signs. The first study concentrated on caesium-137. Around the nuclear plant, places were found containing up to 40.000 becquerels/kg, 8