– 3,000,000 Bq/m2 of cesium from the dam in Fukushima (Fukushima Diary, Mar 13, 2012):
Ministry of Education, Culture, Sports, Science and Technology found out high level of cesium is concentrated in the bottom of the lake called Horai dam. This dam is to generate electricity, located in Nihonmatsu (60km North west to Fukushima plants), where is in Abukuma river.
Prof. Onda from Tsukuba university reported the mud sample taken in 20 cm deep underground of the bottom of the lake contained 3,000,000 Bq/m2 of cesium, where other samples taken in 4 other reservoirs around Horai lake showed 200,000~400,000 Bq/m2 of cesium.(July and August in 2011) 3,000,000 Bq/m2 is as contaminated as soil of 20km area.
Prof. Onda explains, cesium doesn’t melt into the water. Water of downstream is not harmful to drink.
However, they also found out that when the soil is highly contaminated, water of the downstream river is also highly contaminated, which proves Prof. Onda is wrong. Cesium was attached to the small swimming sand, which is smaller than 0.1mm diameter.
Ministry of Land, Infrastructure, Transport and Tourism states there is the risk of the contaminated mud to flow into the downstream in flood, but there is no plan of decontamination at the moment.
Other nuclides such as strontium or plutonium were not tested.
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