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.

Since April 17, we have also conducted sampling surveys at 4 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 2 points each 5 and 30 km off the shore since May 27, and 1
point each 5, 15 and 30 km off the shore since June 2. (We stopped 1 point
15km off the shore and 3 points 30km off the shore since September 1.)

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.

We have conducted an action to lower a detection limit level of the
radioactivity concentration and extended the time for analysis from
October 24, so we will report the data of sampling analysis at offshore
points on the day after next of the collected day.
                                                    (Previously announced)

On December 5 and 6, 2011, we conducted sampling surveys 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.

We reported the above results to NISA as well as to the government of
Fukushima Prefecture today.

Due to the bad weather condition, we conducted sampling survey at 8
location off-coast which had been planned at 9 locations yesterday.

We will continuously conduct the same sampling surveys. 

attachment1: Nuclide Analysis Results of Seawater (PDF 42.2KB) 
attachment2: Radioactivity Density of Seawater (PDF 97.1KB)