– Japan/korea sea contaminated as much as Tokyo bay (Fukushima Diary, Sep 11, 2012):
Tokyo bay is known to be becoming a sea hotspot. (cf. Tokyo bay becoming a hot spot)
In this January, Fukushima Diary introduced the opinion of Mr. Hirose Takashi, a science writer that river carries cesium to Japan/Korea sea. [Link]
However, it had already happened in August of 2011.
Prof. Yamazaki from Kinki university analyzed cesium in sea ground of offshore Niigata prefecture.
He took samples around the mouth of Shinano river. The samples are from the sea ground of 15m, 20m, and 30m deep in the sea. He analyzed it in every 1cm deep in the ground.
The highest reading was 460 Bq/Kg, which was 2~3cm deep in the sea ground. The ground is 30m deep in the sea.
He measured 400~500 Bq/Kg of cesium from Tokyo bay in August of 2011 as well. It was near the mouth of Arakawa river. (cf. Contamination level is increasing in Tokyo Bay)
Japan/Korea sea is as much contaminated as Tokyo day by last summer.