Tuesday, March 22, 2011 18:13 JST  (05:13 am Tuesday March 22 ET) NHK reported that TEPCO has found abnormally high levels of radioactive substances in seawater as far as 16 kilometers from the Fukushima Daiichi nuclear power plant.  

330 meters south of plant

TEPCO sampled seawater 330 meters south of the plant’s drainage exit at 2:30 PM on Monday and found iodine-131 at a level 126.7 times the legal concentration. Cesium-134 was 24.8 times higher and cesium-137 was 16.5 times higher than the level set by law.  A sampling at the same location at 6:30 AM on Tuesday showed levels of iodine were 29.8 times higher, and those of cesium-134 and cesium-137 were 2.5 times and 1.7 times higher, respectively.

8 km south of plant

80.3 times the legal level of iodine-131

1.3 times that of cesium-134.

10 km south of plant

27.1 times the legal concentration Iodine -13

16 km south of plant

16.4 times higher than legal levels of Iodine-131

Risk

The Japan Chemical Analysis Center says there is no need to worry about iodine-131, as its radioactive half-life is just 8 days. Cesium has a much longer half-life and accumulates in marine life.  In addition to milk and leafy vegetables, fish and shellfish need to be continually examined to ensure they do not pose a health risk.

JAMSTEC to sample seawater

According to the IAEA the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) plans to measure radioactivity in the marine environment around the Fukushima Daiichi nuclear power plant March 22-23. Sea water sampling from eight locations will be sampled and analysed by the Japan Atomic Energy Agency (JAEA), and results will be provided on 24 March.