TEPCO has been forced to take drastic measures to deal with the continual contamination of the Pacific Ocean from the crippled Fukushima Daiichi nuclear power plant. To quell the transfer of contaminated marine soil, the utility worked to cover the ocean floor in the port with concrete. They later discovered that the fish life in the port was highly radioactive, which forced them to seal the entrance of the port to prevent as much fish from escaping as possible.
In July of 2012, TEPCO workers sampled marine soil inside of the port entrance of the facility. This week, TEPCO announced that it had detected Plutonium 238, Plutonium 239, and Plutonium 240 in the marine soil in the port at Fukushima Daiichi near the Unit 1 water intake canal.
The report showed that levels of Plutonium 238 had been measured at 0.21 becquerels per kilogram, where before levels had remained either Non-Detect, or under 0.06 becquerels per kilogram according to date from the Ministry of Education, Culture, Sports, Science, and Technology. Prior to the Fukushima Daiichi nuclear disaster, Plutonium 238 had not been detected off short of the nuclear power plant, and the densities of Plutonium 239 and Plutonium 240 were over double what they were before. Plutonium 239 and Plutonium 240 were found to be around 1.2 becquerels per kilogram, significantly greater than previous measurement values in the sea near Fukushima Daiichi (0.17-0.56 becquerels per kilogram).