Radioactive materials in concentration that was up to several hundreds of times the normal level were detected from the soil on the ocean floor in the 300-kilometer strip along the coast from Kesennuma City in Miyagi Prefecture to Choshi City in Chiba Prefecture.
Oh what a surprise. Who could have known?
The Ministry of Education and Science, who did the survey, even goes to contradict the oft-repeated statement by the chief cabinet secretary and says "the marine products may be affected."
Chief Cabinet Secretary Edano's favorite refrain whenever a new leak was found at Fukushima I Nuke Plant was: "It will have no immediate effect" on health, on environment, on anything. (These days, he is busy trying to "qualify" his use of "immediate". Quite funny if the situation is not this dire.)
No word on other nuclides like plutonium, uranium, and strontium.
I'm trying to locate the original survey data at the Ministry's site.
From Mainichi Shinbun Japanese (1:15AM JST 5/27/2011):
文部科学省は２７日、宮城県気仙沼市沖から千葉県銚子市沖まで南北約３００キロにわたる海底の土から、最高で通常の数百倍に当たる濃度の放射性物 質を検出したと発表した。文科省は「海産物に影響が及ぶ恐れがある」としている。東京電力福島第１原発から海に流出した汚染水に含まれた放射性物質が、広 範囲に拡散していることが裏付けられた。
The Ministry of Education and Science disclosed on May 27 that radioactive materials in concentration that was up to several hundreds of times the normal level were detected from the soil on the ocean floor in the 300-kilometer strip along the coast from Kesennuma City in Miyagi Prefecture to Choshi City in Chiba Prefecture. The Ministry says "the marine products may be affected". It is now confirmed that the radioactive materials in the contaminated water released [both intentionally and unintentionally] from TEPCO's Fukushima I Nuclear Power Plant into the ocean have spread far and wide.
The soil samples were taken from May 9 to May 14 at 12 locations about 15 to 50 kilometers off the coast. Radioactive materials were detected in all samples. The highest concentration of radioactive materials was detected from the sample taken from the ocean floor, 126 meters deep, 30 kilometers off the coast of Fukushima I Nuke Plant. Cesium-134 was 260 becquerels/kilogram, and cesium-137 was 320 becquerels/kilogram.
In comparison, in the survey done in 2009 in the approximately the same location, cesium-134 was not detected, and cesium-137 was 1 becquerel/kilogram.
Iodine-131, whose half life is short and was not detected at all in the 2009 survey, was found at 1.6 to 6.1 becquerels/kilogram.
The spread of cesium was more concentrated north of Fukushima I Nuke Plant. Cesium-137 at a location off the coast of Kesennuma City in Miyagi Prefecture, 70 kilometers north of the plant, was 110 becquerels/kilogram, whereas at a location off Kita-Ibaraki City in Ibaraki Prefecture, 70 kilometers south of the plant, it was 12 becquerels/kilogram.
According to the Ministry, "There's a variation in the amount of radioactive materials due to the variation in ocean floor topography and the effect of the ocean current."