|October 25, 2012
In the immortal words of Bruce-the-shark from Finding Nemo: "Fish are friends, not food"; but in Fukushima, they are neither! As Bloomberg reports, radiation levels of fish caught off the coast of Northern Japan are as high as they were a year ago with contamination levels particularly high among bottom-dwellers. There remains a fishing ban on these bottom-dwelling fish as 40% are still above the limit for human consumption. As one scientist noted, "This means that even if these sources were to be shut off completely, the sediments would remain contaminated for decades to come." So, today's lesson is, Fukushima fish are neither friends nor food, but more like lava lamps we suspect.
Fish caught in waters off the coast of northern Japan, where an earthquake triggered a radiation leak at the Fukushima power plant, are still as contaminated today as a year ago, a study found.
Contamination levels were particularly high among species dwelling at the bottom of the ocean, as sinking radioactive materials tainted the seafood, the research showed. The findings, published today in the journal Science, suggest there is a continued source of radiation from the seafloor that will have a lasting impact, said Ken Buesseler, the study’s author.
“This means that even if these sources were to be shut off completely, the sediments would remain contaminated for decades to come,” said Buesseler, a senior scientist at Woods Hold Oceanographic Institution in Woods Hole, Massachusetts.
In waters off Fukushima, where there is a ban on fishing for bottom-dwelling species, 40 percent of fish are above the limit for human consumption based on Japanese regulatory limits, Buesseler said.
About 3,500 terabecquerels of radioactive cesium 134 and 3,600 terabecquerels of cesium 137 may have leaked into the sea between March 26 and Sept. 30 last year after a three-reactor meltdown at the Fukushima Dai-Ichi nuclear plant, operator Tokyo Electric Power Co. said in a statement in May.
More than 80 percent of the radioactivity from the nuclear plant was released offshore or into the ocean from waters used for cooling, according to the study.
Radioactive cesium levels in seafood haven’t dropped as of August, except perhaps in fish that live near the surface, Buesseler said. Two greenlings caught in August closer to shore off Fukushima contained more than 25,000 becquerels per kilogram, compared with the maximum permissible level of 100 bq/kg set by the Japanese government, the author said.