Radiation in seawater at new high Radiation 4,385 times higher than the legal standard has been detected in seawater at a location 330 meters south of the troubled Fukushima Daiichi nuclear plant. Tokyo Electric Power Company says 180 becquerels per cubic centimeter of radioactive iodine-131 have been detected in seawater sampled on Wednesday afternoon. The figure is far above the 3,355-times level detected on Tuesday. Wednesday's sampling also revealed cesium-137, which has a half-life of 30 years, at a level 527 times higher than the legal standard. Japan's Nuclear and Industrial Safety Agency says no fishing is being carried out in waters within 20 kilometers of the plant, and the radiation is likely to be diluted significantly by the time humans take it in through seafood.