Samples from an entire 300 km stretch of seafloor off the Fukushima coast indicate radioactivity 50-100 times higher than normal

As far as 30 kilometers out

Perhaps MEXT realized that Greenpeace was making them look bad by being so conscientious about testing sea life near Dai-ichi, so they conducted their own measurements of the seabed off the coast of Fukushima. From NHK:

Japan's science ministry has detected extraordinarily high levels of radioactive cesium in seafloor samples collected off Miyagi and Ibaraki Prefectures.

Experts say monitoring should be stepped up over a larger area to determine how fish and shell fish are being affected.

The ministry collected samples from 12 locations along a 300-kilometer stretch off Fukushima prefecture's Pacific coast between May 9th and 14th. It hoped to get an idea about the spread of nuclear contamination caused by the accident at the Fukushima Daiichi nuclear power plant.

Radioactive substances were found in all locations, including those off Miyagi and Ibaraki Prefectures, which had not been previously investigated.

Radioactive cesium 137, measuring 110 becquerels per kilogram or about 100 times the normal level, was found in samples collected from the seabed 30 kilometers off Sendai City and 45 meters beneath the surface.

Samples collected from the seabed 10 kilometers off Mito City and 49 meters beneath the surface measured 50 becquerels or about 50 times the normal level.

Professor Takashi Ishimaru of the Tokyo University of Marine Science and Technology says plankton most probably absorbed the radioactive substances carried by the current near the sea surface, and then sank to the seabed.

He said monitoring must be stepped up over a larger area, as radioactive materials in the seabed do not dissolve quickly, and can accumulate in the bodies of larger fish that eat shrimp and crabs that live on the seafloor.

Saturday, May 28, 2011 22:21 +0900 (JST)

In light of those findings, the combination of radioactivity in seawater and high tides will pose problems for Miyagi and Ibaraki

Shinomaki, Miyagi, Japan. (Asahi Shimbun via Getty Images)

I haven't heard any reporting on it yet, but aren't higher concentrations of isotope in ocean water a cause for concern in Miyagi, Ibaraki and other port areas around Fukushima?  Twice a day, every day, the high tide brings in fish and debris right up to the front doorsteps of residents homes.

I would imagine this as a potential health hazard and cause for evacuation.  Since they haven't done so yet, maybe they should start investigating amounts of radioactivity in water at high tide.  These people tread through it everyday. These communities will face permanent, regular flooding because the Japan earthquake shifted the local geography.  Miyagi is 1.2 meters lower than it used to be.