Update on the Fukushima Nuclear Power Plant: What you need to know about radiation in Pacific Seafood

Created on Tuesday, 17 December 2013

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. On July 22, 2013, over two years later, the Tokyo Electric Power Company (Tepco) 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. There are concerns about the local effects of the radiation to Japanese seafood, but radiation from Fukushima rapidly dilutes in concentration as currents carry it across the Pacific, making the risk of human health impacts from contamination along the West Coast extremely low. Scientists predict that waters contaminated with radionuclides from Fukushima will reach the northwestern American coast by early 2014 (Rossi et al 2013). However, this should not be cause for alarm. On December 5, 2013, the chairwoman of the U.S. Nuclear Regulatory Commission announced that the highest amount of radiation that will reach the U.S. coast is 100 times lower than the drinking water standard. 

There are several different radionuclides that are entering the ocean near the leaking power plant. Until the Fukushima plant meltdown, the primary source of cesium-137 to the ocean was from weapons testing in the 1960s and from Chernobyl fallout, to a lesser extent (Cs-134 was also released but has long since decayed). Because both cesium isotopes (Cs-134 and Cs-137) rapidly disperse in seawater and Cs-134 has a short half-life, any Cs-134 detected in fish samples can be traced back to the Fukushima power plant (Madigan et al 2013). Strontium-90 is another radionuclide leaking from the plant in small amounts. As of November 2013, the levels of strontium-90 found in fish near the nuclear power plant were far lower than that of cesium isotopes.    

radioactive-bluefin-imageScientists from around the world are testing organisms near the power plant for levels of radiation to determine if there is a risk to human health. A study conducted by scientists from Woods Hole Oceanographic Institution tested fish for radiation in waters near the power plant and found that the median concentration of Cesium-137 was about 150 times below the Japanese legal limit (Buesseler et al 2012). The researchers’ conclusion from the study was that, even within 30 kilometers of the leaking nuclear power plant, seafood is safe for human consumption. Radiation risks from Cesium-134 and -137 to humans consuming seafood are well below those from radionuclides that occur naturally in seawater, which include potassium, polonium, and even uranium  (Buesseler et al 2012). 

Along the west coast of the United States, low levels of cesium radioisotopes from Fukushima have been found in Pacific bluefin (Madigan et al. 2012) and albacore tunas. Again, this should not cause alarm to seafood lovers, as the levels of those radioisotopes were far lower than naturally occurring radioisotopes (Fisher et al 2013). In both studies, the researchers involved were more excited about the ability to use radiation from Fukushima to learn about the seasonal migration patterns of tuna than the radioactivity of the fish. Scientists cannot say that there is no health risk from eating Pacific seafood with traces of radiation from Fukushima, but they do agree that the risk is extremely low. Personal assessment of the risks associated with consuming fish that potentially carry Fukushima-derived radiation should be evaluated in the context that almost all foods, including produce and fish, carry (and have always carried) radioactive material from natural sources in the earth.

The U.S. National Oceanographic and Atmospheric Administration (NOAA) is responsible for testing marine debris from Japan for radiation contamination. The plume of water from Fukushima is predicted to reach the northwestern American coast by early 2014 (Rossi et al 2013). As of November 2013, detectable levels of radiation from Fukushima have not been found in any marine debris that has made it to the west coast.  

The Food and Drug Administration (FDA), Environmental Protection Agency (EPA), and the National Oceanographic and Atmospheric Administration in United States are monitoring radiation from Fukushima. As of June 20, 2012, the FDA has tested 1,313 samples for radionuclide contamination. One sample has been found to have detectable levels of radiation from the nuclear power plant, but it was still well below the safety threshold.   

There is no question that there are major concerns regarding the effects of radiation from the damaged Fukushima Daiichi Nuclear Power Plant on human health and the environment. However, the key results from these studies and from the government tests have been misrepresented in the media and have led to the concern that seafood in the Pacific is contaminated from the Fukushima plant and unsafe to eat. While Japanese subsistence fishers may need to take caution, people eating seafood from the eastern Pacific do not need to spend too much time worrying. Based on the scientific information available, consuming Pacific seafood is safe. We will update our research on this situation as new information becomes available. 

Buesseler, K.O., S.R. Jayne, N.S. Fisher et al. (2012). Fukushima-derived radionuclides in the ocean and marine biota off Japan. Proceedings of the National Academy of Sciences. 109(16): 5984-5988.

Fisher, N.S., K. Beaugelin-Seiller, T.G. Hinton, Z. Baumann, D.M. Madigan, J.Garnier-Laplace. (2013). Evaluation of radiation doses and associated risk from the Fukushima nuclear accident to marine biota and human consumers of seafood. Proceedings of the National Academy of Sciences. 110(26): 10670-10675.  

Madigan, D.J., Z. Baumann, N.S. Fisher. (2012). Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proceedings of the National Academy of Sciences. 109(24): 9483-9486. 

Madigan, D.J., Z. Baumann, O.E. Snodgrass, H.A. Ergül, H. Dewar, N.S. Fisher. (2013). Radiocesium in Pacific bluefin tuna Thunnus orientalis in 2012 validates new tracer technique. Environmental Science & Technology. 47(5): 2287-2294. 

Rossi, V., E. Van Sebille, A.S. Gupta, V. Garçon, M.H. England. (2013). Multi-decadal projections of surface and interior pathways of the Fukushima Cesium-137 radioactive plume. Deep-Sea Research I. 80(2013): 37-46.