Scientists found traces of radiation in bluefin tuna caught off the coast of California, months after the Fukushima nuclear disaster in Japan. The levels of radioactivity were still well below United States and Japanese safety limits.
According to a study published Monday in the Proceedings of the National Academy of Sciences Journal, small amounts of radioactive cesium isotopes were detected in 15 Pacific bluefin caught near San Diego last summer. The fish showed levels of cesium-137 and cesium-134 that were 10 times higher than in tuna caught previously in the same area.
According to the BBC, the detection gave a "clear indication that it originated from the Fukishima accident, less than five months before the fish were caught. The leak at the nuclear power plant released radioactive material into the Pacific Ocean, which fish can pick up from the water they swim in and the food they eat. In turn, predators that eat contaminated fish accumulated a higher concentration of cesium because of an effect known as biomagnification.
The study's co-author, Nicholas Fisher of Stony Brook University, said the research team expects the radiation to decline gradually. They plan to conduct a follow-up study later this year.