Many fish caught off the coast of Fukushima are still showing high levels of radioactive cesium. This indicates that, since the catastrophic earthquake and tsunami that caused the nuclear disaster on 11 March 2011, the seafloor or leakage from the damaged reactors must still be contaminating the area – something that could affect fisheries for decades, a researcher warned.
According to data collected by Japan's Ministry of Agriculture, Fisheries and Forestry (MAFF), 40 per cent of bottom-dwelling fish such as cod, flounder and halibut are above the limit of cesium-134 and cesium-137, Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution (WHOI) in Massachusetts informed in an article published this week in the journal Science.
Buesseler looked at a year’s worth of the government’s data and found that the levels of contamination in almost all kinds of fish are still not falling, BBC reports.
"The (radioactivity) numbers aren't going down. Oceans usually cause the concentrations to decrease if the spigot is turned off," Buesseler clarified, The Associated Press reports. "There has to be somewhere they're picking up the cesium."
"Option one is the seafloor is the source of the continued contamination. The other source could be the reactors themselves," he said.
Most fish and seafood from along the Fukushima coast are banned from the domestic market and export. Although in June, authorities lifted bans on octopus and sea snails that showed very low levels of radiation, the most contaminated fish were caught in August 2012 -- the two greenlings, which are bottom-feeders, had cesium levels of more than 25,000 Bq per kg, 250 times the level the Japanese Government considers safe.
A government fisheries official, Chikara Takase, at that point said that the high numbers were detected only in certain kinds of fish sampled in the restricted waters closest to the nuclear plant.
Plant operator Tokyo Electric Power Co admitted that some radioactive water used to cool the Fukushima reactors leaked into the ocean, most recently last April.
"Given the 30-year half-life of cesium-137, this means that even if these sources (of contamination) were to be shut off completely, the sediments would remain contaminated for decades to come," Buesseler wrote.
Hideo Yamazaki, a marine biologist at Kinki University, also thinks that the cesium is leaking from the plant and that it will contaminate seafood for more than 10 years. He believes the plant will continue to leak until cracks and other damage are repaired, and it remains unclear how and when that work will be completed, as radiation levels in the reactors are too high for humans and robots.
Buesseler said predicting patterns of contamination requires careful study of the ocean waters and sediments to determine how quickly the ecosystem will recover.
EC Reviews Measures on Imports from Japan
Experts meeting in the European Commission's Standing Committee on the Food Chain and Animal Health (SCoFCAH) endorsed a Commission proposal to revise rules on import conditions of food and feed originating from Japan following the Fukushima nuclear accident.
Existing restrictions for food and feed imports coming from the prefecture Fukushima are maintained whereas control measures have been eased for several other prefectures.
For the prefecture Fukushima, the existing measures applying to all food and feed, with the exception of alcoholic beverages, are maintained until 31 March 2014.
Based on over 40,000 samples of products harvested in the second growing season after the nuclear accident, the restrictive measures in place have been eased for 11 prefectures (Yamanashi, Shizuoka, Gunma, Ibaraki, Tochigi, Miyagi, Saitama, Tokyo, Iwate, Chiba and Kanagawa).
An interim review is foreseen before 31 March 2013 for crops where samples of products for the second growing season (March-November) were not available in time for this review.
For the control at import, a reduction of the frequency of controls to five per cent will apply. Based on the monitoring results from the 2013 growing season, it is foreseen to undertake a review of these measures shortly before 31 March 2014.
The measures will be published at the end of this month following the adoption of the proposal by the Commission and are foreseen to enter into force on 1 November 2012.