On March 21, 2011, we conducted sampling, as a part of monitoring of
surrounding environments, and detected radioactive materials in the
seawater around the water discharge canal (of the south side) of Fukushima
Daiichi Nuclear Power Station, which was damaged by
the Tohoku-Taiheiyou-Oki Earthquake. Therefore, we informed Nuclear and
Industrial Safety Agency (NISA) and the government of Fukushima Prefecture
of the results. 
Since March 22, we have conducted seawater sampling surveys at four points
off the shore of Fukushima Daiichi Nuclear Power Station (twice a day at
two points out of such four points since March 26). 

Since April 17, we have also conducted sampling surveys at four points (2
points have been added since April 26, another 3 points since April 30,
and another 1 point since May 5, 10 points in total) of 3 km off the shore
of Fukushima Daiichi Nuclear Power Station, two points of 8 km off the
shore of the Power Station and 6 points of 15 km off the shore of the
Power Station and informed them of evaluation results.
Also, we added another 4 points off the shore since May 27 and 3 points
off the shore since June 2.

The data of three detected nuclides (Iodine-131, Cesium-134 and
Cesium-137) will be reported as fixed data. Other nuclide figures are to
be re-evaluated. 
                                                    (Previously announced)

On August 3, 2011, we conducted sampling to evaluate the spread of
radioactive materials to the ocean which were detected at Fukushima
Daiichi Nuclear Power Station. As a result, radioactive materials were
detected as shown in the attachment. Since we conducted closure works by
steel sheet pile around the south area of open channels of Units 1 to 4
yesterday, we increased frequency of sampling in order to monitor
environmental impacts of the work.  
Also we analyzed Strontium in the seawater sampled on July 14, 2011, and
total alpha and total beta rays in the seawater sampled on June 13 and 14,
and as a result  Strontium-89, 90 and total beta rays were detected as
described in the attachment. 
We have already summarized the results and reported them to NISA and the
government of Fukushima Prefecture. 
We will continuously conduct the similar sampling. 

attachment1: Results of Nuclide Analysis of Seawater(PDF 73.7KB) 
attachment2: Radioactivity Density of Seawater(PDF 77.8KB)