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 radioactive caesium. In addition to the large releases of contaminated water (520 tons and 4.7 PBq) believed to have leaked from unit 2 from mid-March until early April, another release of radioactive water is believed to have contaminated the sea from unit 3, because on 16 May TEPCO announced seawater measurements of 200 Bq per cubic centimeter of caesium-134, 220 Bq per cubic centimeter of caesium-137, and unspecified high levels of iodine shortly after discovering a unit-3 leak. At two locations 20 kilometers north and south and 3 kilometers from the coast, TEPCO found strontium-89 and strontium-90 in the seabed