Update on Fukushima: Should We Be Worried About Radioactive Seafood?

In March 2011, the Fukushima Daiichi nuclear power plant in Japan suffered major damage when it was hit by a powerful 9.0 earthquake and subsequent tsunami, resulting in the largest nuclear disaster since Chernobyl. Over two years later, the Tokyo Electric Power Company (Tepco) recently acknowledged that radioactive water from the plant continues to leak into the Pacific ocean at a rate of nearly 300 tons per day, causing global concern about contaminated seafood. 

Scientists have long suspected that radioactive water was still leaking into the ocean. Last October Ken Buesseler, a marine chemist from Woods Hole Oceanographic Institute, found that levels of radioactivity in samples taken from fish, shellfish, and algae around Fukushima were not declining with time. A new study published in the peer-reviewed journal Deep-Sea Research predicts that ocean water contaminated with radionuclides from Fukushima will reach Hawaii and the west coast of United States in early 2014.

Fears about the safety of seafood from the Pacific have prompted scientists to investigate some fish species for traces of radiation. To determine what effect the radiation is having on the marine food web further from Japan, another group of scientists from Stanford and Stony Brook Universities collected tissue samples from Pacific bluefin tuna caught off the coast of California. They found that all 15 tunas tested had trace amounts of radioisotopes from the Fukushima plant. 

Given all this disturbing news, should we avoid eating seafood from the Pacific ocean?

Not according to the marine scientists who published the studies described above. Physical oceanographers are more excited than fearful of the radiation plume heading for the west coast. By monitoring the plume’s spread across the Pacific, researchers can study long-term ocean circulation patterns and improve their models. Due to the rapid dilution of radiation in the Pacific Ocean currents, levels of radionuclides in the plume will be far below the U.S. Environmental Protection Agency’s safe limits for drinking water by the time it reaches our shores.

The majority of fish tested in waters near Fukushima had levels of radiation that were well below safe limits for consumption. The level of radiation found in the bluefin tuna off California was also considerably lower than radiation levels that are naturally found in the fish. In fact, the significance of the studies was not necessarily the implications for human health, but rather that scientists could use the signals from Fukushima to understand bluefin migration patterns across the Pacific.

Unfortunately the key results from these studies have been misrepresented in the media, and have led to the concern that seafood in the Pacific may be contaminated from the Fukushima plant and is unsafe to eat. While Japanese subsistence fishers may need to take extra caution, people eating seafood from the eastern Pacific do not need to spend too much time worrying. The latest report released by the Stony Brook University researchers assures us that, “although uncertainties remain regarding the assessment of cancer risk… the dose received from Pacific bluefin tuna consumption by subsistence fishermen can be estimated to result in two additional fatal cancer cases per 10,000,000 similarly exposed people.”

To learn more, visit Woods Hole Oceanographic Institute’s informative FAQ.