Effect of Fukushima Daiichi Nuclear Power Plant accident on lakes in Fukushima Prefecture and Niigata City

The Fukushima Daiichi Nuclear Power Plant Accident happened in 12 - 15th March 2011. This accident caused to the radioactive contamination in the near area. In this work, some lake waters and the sediments were collected in Fukushima Prefecture and Niigata City to clarify the effect of the accident on the area contaminated. As to the collected lake water, an enrichment of 'the specific activity of tritium (T specific activity)' in each water collected was carried out by the solid polymer electrolyte (SPE) apparatus, and the T specific activity was measured by a liquid scintillation counter. Based on the T specific activity thus measured, the influence of the accident to the environment was investigated. At the same time, specific activities of radioactive caesiums in the lake sediments were also measured. Consequently, the influence of the Fukushima Daiichi Nuclear Power Plant Accident to the adjacent lakes (e.g., in Fukushima Prefecture and Niigata City) was quantitatively clarified. From the above-mentioned matters, it is found that the effect of the accident on Niigata City is so small, and the accident gradually decreases in Fukushima Prefecture. (author)