Caesium-137 alienation around the Chernobyl nuclear power plant. Together with caesium-134, iodine-131, and strontium-90, caesium-137 was among the isotopes distributed by the reactor explosion that constitute the greatest risk to health. The mean contamination of caesium-137 in Germany following the Chernobyl disaster was 2000 to 4000 Bq/m. This corresponds to a contamination of 1 mg/km of caesium-137, totaling about 500 grams deposited over all of Germany. In Scandinavia, some reindeer and sheep exceeded the Norwegian legal limit (3000 Bq/kg) 26 years after Chernobyl. As of 2016 the Chernobyl caesium-137 has decayed by half, but could have been locally concentrated by much
Radiation effects from the Fukushima Daiichi nuclear disaster just like caesium-137 as indicated on an earlier map. But I-131 was also found south of the plant at relatively high levels, even higher than those of caesium-137 in coastal areas south of the plant. According to the ministry, clouds moving southwards apparently caught large amounts of iodine-131 that were emitted at the time. The survey was done to determine the risks for thyroid cancer within the population. On 31 October the Japanese ministry of Education, Culture, Sports, Science and Technology released a map showing the contamination of radioactive tellurium-129m within a 100-kilometer radius around the Fukushima No. 1 nuclear