Fish containing 258 times the legal limit of radioactive cesium have been found in waters off the crippled Fukushima No. 1 nuclear power plant, the plant operator, Tokyo Electric Power Co., said on Aug. 21.
The reading for two rock trout, caught about 20 kilometers to the north of the plant, showed 25,800 becquerels per kilogram, the highest yet detected in surveys conducted after last year’s nuclear accident.
Consuming 200 grams of the fish would amount to an internal radiation exposure of 0.08 millisievert for a human. The annual safety limit for radiation exposure from food products is 1 millisievert per person.
Fishermen currently do not fish in the waters in question, however, and no rock trout from the area have been distributed to the market.
Tetsu Nozaki, who heads the Fukushima Prefectural Federation of Fisheries Co-operative Associations, expressed concern about the finding.
“The reading was way beyond the levels recorded before,” he said. “It is worrying.”
The finding came after the federation resumed catches of some octopus and shellfish in waters off Soma, in the northern part of the prefecture, between June and early August on a trial basis. Those fish were distributed to markets, including Tokyo.
Nozaki said the federation will make a formal request for TEPCO to find out why such high levels of contamination were detected in the rock trout.
“We operate on the assumption that no additional contaminated water was leaked into the sea from the plant,” he said.
TEPCO officials said there could be so-called “hot spots” at the bottom of the sea where cesium is concentrated because rock trout usually live near the seabed. The company plans to study cesium levels of the crabs and the shrimp that rock trout feed on.
In a survey conducted in April last year, 14,400 becquerels per kilogram was detected for sand eel caught off the coast of the prefecture.
In March, landlocked salmon in the Niidagawa river near Iitate, a village to the northwest of the plant, measured 18,700 becquerels per kilogram.
