Japan Discloses Ocean Soil Cesium Data off Fukushima

Tokyo, June 13 (Jiji Press)--Japan's Nuclear Regulation Authority on Friday disclosed the results of fiscal 2013 research on the concentrations of radioactive materials in ocean soil off Tokyo Electric Power Co.'s <9501> crippled Fukushima No. 1 power station. Soil collected some 6 kilometers from the power plant included up to 2,000 becquerels of cesium-137 per kilogram. The cesium's half-life period is about 30 years. The authority said it is difficult to give an assessment of the figure because there is no standard against which evaluations can be made. The NRA said it will continue its research. The power station in northeastern Japan had an unprecedented triple reactor meltdown in March 2011, polluting the environment with radioactive materials from the facility. On the seabed about 4 kilometers off the facility, soil containing 1,000 becquerels of cesium-137 was collected from about 20 locations, the authority said, noting that soil containing cesium tends to accumulate in depressed places. Distributions of cesium-137 on the seabed off the TEPCO power station confirmed in the latest research were roughly the same as seen in the outcome of similar research conducted by the Fisheries Agency in fiscal 2012, the authority said. Cesium-137 levels were particularly high in areas near the mouth of the Abukuma River which flows from Fukushima to Miyagi Prefectures. The highest reading was 2,700 becquerels detected from soil collected 2.5 kilometers east and 2.3 kilometers south of the river's mouth in Sendai Bay. But cesium concentrations in the areas did not fluctuate much during the year, the NRA said. The research, conducted by the University of Tokyo and the National Maritime Research Institute, covered a 1,000-square-kilometer offshore area near the Fukushima No. 1 plant as well as areas around the Abukuma River. END