Radiation levels in seawater off Japan plant spike to all-time highs 30 Mar 2011 The level of radiation in ocean waters off Japan's embattled Fukushima Daiichi plant has risen to new highs -- measuring 4,385 times the standard -- an official with Japan's nuclear and industrial safety agency said Thursday. The samples, taken Wednesday from a monitoring post 330 meters (361 yards) into the Pacific Ocean, marked a significant increase from the previous day's news that the same I-131 isotope was 3,355 times the regulatory limit. Just last Friday, the radiation levels were 104 times more than a typical level.