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Fukushima and Radioactivity in Seafood

The majority of radioactive fallout from the Fukushima nuclear power plant tragedy was absorbed by the Pacific Ocean. What does that mean for seafood safety?

June 17, 2013 |
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Supplementary Info

Sources Cited

A. Kelecom, R. de Cássia dos Santos Gouvea. Increase of 210Po levels in human semen fluid after mussel ingestion. J. Environ. Radioact. 2011 102(5):443 - 447

G. Collodel, S. Capitani, A. Pammolli, V. Giannerini, M. Geminiani, E. Moretti. Semen quality of male idiopathic infertile smokers and nonsmokers: An ultrastructural study. J. Androl. 2010 31(2):108 - 113

G. A. Wetherbee, D. A. Gay, T. M. Debey, C. M. B. Lehmann, M. A. Nilles. Wet deposition of fission-product isotopes to North America from the Fukushima Dai-ichi incident, March 2011. Environ. Sci. Technol. 2012 46(5):2574 - 2582

P. Thakur, S. Ballard, R. Nelson. Radioactive fallout in the United States due to the Fukushima nuclear plant accident. J. Environ. Monit. 2012 14(5):1317 - 1324

D. J. Madigan, Z. Baumann, N. S. Fisher. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proc. Natl. Acad. Sci. USA 2012 109(24):9483 - 9486

S. W. Fowler. 210Po in the marine environment with emphasis on its behaviour within the biosphere. J. Environ. Radioact. 2011 102(5):448 - 461

H. S. Karagueuzian, C. White, J. Sayre, A. Norman. Cigarette smoke radioactivity and lung cancer risk. Nicotine Tob. Res. 2012 14(1):79 - 90

R. B. McFee, J. B. Leikin. Death by polonium-210: Lessons learned from the murder of former Soviet spy Alexander Litvinenko. Semin Diagn Pathol 2009 26(1):61 - 67

H. Sugiyama, H. Terada, K. Isomura, I. Iijima, J. Kobayashi, K. Kitamura. Internal exposure to 210Po and 40K from ingestion of cooked daily foodstuffs for adults in Japanese cities . J. Toxicol. Sci. 2009 34(4):417-425

A. Aarkrog, M.S. Baxter, A.O. Bettencourt, R. Bojanowski, A. Bologa, S. Charmasson, I. Cunha, R. Delfanti, E. Duran, E. Holm, R. Jeffree, H.D. Livingston, S. Mahapanyawong, H. Nies, I. Osvath, Li Pingyu, P.P. Povinec, A. Sanchez, J.N. Smith, D. Swift. A Comparison of Doses from 137Cs and 210Po in Marine Food: A Major International Study . J. Environ. Radioact. 1997 34(1):69-90

J. J. Mangano, J. D. Sherman. An unexpected mortality increase in the United States follows arrival of the radioactive plume from Fukushima: Is there a correlation? Int J Health Serv. 2012 42(3):557-559

J. J. Mangano, J. D. Sherman. Fukushima update: Radioactive fallout and mortality increases in the United States: Is there a correlation? . Int J Health Serv. 2012 42(3):561­-570



With prevailing westerly winds over Japan, radioactive fallout from the Fukushima nuclear power plant tragedy was detected throughout North America at levels comparable to those seen 25 years earlier from Chernobyl, the only other category 7 nuclear events in history.

The highest levels of radioactive iodine in rain water was found in Boise, Idaho and the highest levels in milk were found in San Francisco at levels ten times higher than the federal maximum allowed in drinking water, but below that which would be expected to pose a direct threat to U.S. public health. 

A controversial paper in the International Journal of Health Sciences suggested the radioactive plume from the nuclear meltdowns in Fukushima may be responsible for the subsequenta bump in U.S. mortality similar to what we saw after Chernobel, though the authors themselves underscore their research shows merely a correlation, and potential evidence of a causal link, and that more research is necessary.

Of all the radiation released, only a tiny fraction of the fallout reached U.S. shores—most was absorbed by the Pacific Ocean. What does that mean for seafood safety? 

Reserachers report unequivocal evidence that Pacific bluefin tuna have transported Fukushima-derived radioactive fallout across the entire North Pacific Ocean. Tuna actually migrate from Japan to California and appeared to have taken some radioactivity with them.

Even there was 10-fold spike in radioactive cesium levels in tuna, they put it in context by noting the baseline levels of radioactivy in fish even before Fukushima due to everything from thermonuclear weapons tests and sunken nuclear submarines to just the radioactive elements found naturally in the earth's crust. The levels in seawater of radioactive polonium are miniscule, but it strongly bioaccumulates up the food chain into fish.

This is the same polonium used in the horrific assassination of Russian dissident Litvinenko. That's the same polonium in fish. It's a by-product of uranium decay and frequently cited as one of the reasons that tobacco is so carcinogenic. Something the tobacco industry was well aware of and could have easily removed, but the process that could have removed the polonium affected the absorbability of nicotine and the loss of the nicotine “kick” sensation was found unacceptable by industry executives. And so they kept the polonium in.

The radioactive polonium in cigarettes has been specutively blamed for the link between smoking and male infertility, but most of human exposure comes from diet, mostly from fish and shellfish. And this was before Fukushima. So what then happens if you eat seafood? Researchers measured the increase in radioactive polonium levels in semen after a single seafood meal. It caused a 300% spike in levels. Probably not enough to cause infertility, but that was just one meal. Whether the kind of dose you can get from eating seafood would be enough to damage sperm enough still needs to be established. You may have to eat as much as a pound of seafood a month, before one might realize harmful effects of the radiation.

Interestingly, there's 8 times more polonium in cooked shrimp than in raw. Isn't that fascinating? They think it's because most of the polonium is in the shrimps' internal organs, which is released in to the boiling water and contaminates the muscle, so gutting crustaceans before cooking may decrease radiation exposure. 

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

Unfortunately our oceans have become humanity's sewers; everything eventually flows down into the sea. This has implications for other aspects of seafood safety: 

More on infertility in:

Cigarette manufacturers' protection of stockholders over the public is not unique to that sector. More industry hijinks in:

The greatest radiation exposure risk comes not from Fukishima fallout or the polonium naturally found in seafood, but from doctors. Stay tuned for my next video, Cancer Risk from CT Scan Radiation. If you sign up for daily, weekly, or monthly updates I'll email when new videos are released.

For more context check out my blogs: Top 10 Most Popular Videos from 2013, How Risky are CT Scans?Fukushima Radiation and Seafood, Are Dental X-Rays Safe?, Dealing with Air Travel Radiation Exposure, and Ginger & Lemon Balm for Radiation Exposure.

  • LumLum2500

    So what about seaWEED from Japan after Fukushima?

    • Amy P.

      Don’t eat it. Get it from Maine

  • Coacervate

    Do you ever feel like, i dont know, i just cant shake this overpowering urge to dig a big hole in the back yard and climb in.

    Obituary: Planet Earth, aged 4.5 billion years, finally died of a thousand cuts. Donations may be sent to the glow-in-the-dark roach foundation.

  • Noni

    What about swimming in the Pacific here in California?

  • elsie blanche

    A bunch of USA’s food is grown in California, lots of fruit and veggies and nuts and seeds…..wondering if that toxic air drifting over from Japan lends itself to the accumulation of this junk in our vegan staples?! What’s going to happen if/when one of California’s nuke reactors implodes due to an earthquake?

  • Merio

    This huge problem is brought to you by the Nuclear Industry that wants to play with forces that are far from being adequately understood…

    • b00mer

      The fission process and its risks are well understood. The problem is they don’t care.

  • Thea

    A “pound a month” would be extremely easy to meet, I would think. On more than one occasion, I have heard “experts” recommend eating fish at least once a week. Eat fish 4 times a month and one could easily hit a pound. While I understand that the science is not yet conclusive, if the suggested harmful limit of a pound a month is true, then bye, bye sperm for those males following mainstream nutrition advice.

    On one hand, I think, “so sad”. On the other hand, there are too many humans already ruining the oceans. …

    • Amy P.

      The “norm” for sperm count has gone from 80,000/in2 to 20,000/in2 in the last 10 years.

      • Thea


  • SheilaTS

    I saw seaweed was a biggest slice on the pie chart after seafood. I’m assuming that needs to be avoided too.

  • Sharynski

    Is Maine seaweed safe for consumption?

    • Amy P.

      Yes, so far.

  • Plantstrongdoc

    This is the biggest experiment of them all: How many years will it take for one species to destroy a planet. Within the last 100 – 200 years we have polluted the oceans with dioxin, mercury, nuclear waste and prescription drugs, polluted the air with dust, smoke and harmful gases from the burning of fossil fuels such as coal, oil, natural gas, and gasoline, not to mention the greenhouse effect, we have destroyed the ozone layer making it dangerous to get vitamin D from its original source – the sun, deforestation to produce livestock (which ironically turns out to kill us prematurely), species become extinct because of human behaviour, we process food so much that it does not look like food anymore, and then wonder why we get sick, we release GMO into the environment etc, etc…….Humans are great….

  • Coacervate

    Is there a forum for Dr Greger’s work or for the WF/PB community? I would be grateful for information, thanks.

  • Lisa

    Dr. Greger, You’ve done a number of videos on the health benefits of Green Tea. But what about radioactivity in Green Tea imported from Japan or China? How can we be sure the tea we’re drinking is safe?

    • Coacervate

      Good question. But radioactive muck is only one factor. Chinese rice is loaded with cadmium, but so is clean, green New Zealand produce and meat:

      “In New Zealand the group with the highest cadmuim levels are the vegetarians…”

      and the meat that is too poisonous to export?… cat and dog food.

      So how do we know our food is safe? We dont, we cant, We are powerless. I tried to make my own soil, but if the raw materials are loaded with heavy metal, then so is the compost.

      In the USA it is arsenic in rice. This is just the little icy tip of the berg we see/hear about. What behemoths are lurking beneath the surface?

      I know. Lets reproduce ourselves faster. 8, 9 10 billions. Vison that one. The teeming masses all working and praying together to make the Commons a paradise. la la la Technology will save us. Run Logan, Run!

      • preff

        “Clean, green New Zealand”?? Just do a search on pesticide use in NZ and you might want to rethink that.

        • Amy P.

          I think he was being sarcastic

    • LumLum2500

      I get organic green tea from EarthFare, made in the U.S.A.

      • shea

        Call them and ask how much fluoride is in the tea. Ask if they have even measured it. Organic or non-organic tea, apparently tea pulls a lot of fluoride from soil. Do you add lemon to tea? I’ve read that adding lemon to tea dramatically increases aluminum in the tea.

        • Amy P.

          BLACK tea already has high levels of AL in it. The lemon makes the absorption rate go up a bit.
          Herbal tea has much less AL in it.

    • Harriet Sugar Miller

      As for teas from Japan, you may want to look
      for teas grown in regions far south of Fukushima– especially the Kagoshima prefecture, the second largest tea-growing area and thousands of kilometres away. A windshift during a critical period brought radionuclides back onto some parts of the main island. Initially, some samples of teas from Shizuoka, Japan’s largest tea-growing region, showed evidence of Fukushima’s footprint; according to the Shizuoka prefecture,teas tested in 2012 and 2013 appeared to be safe.

      Still, Japan’s federal government says that
      tea leaves are among the “food items from which 1/2 of the
      maximum limits for radioactive cesium has been detected,” and monitoring is continuing. (That’s from a March 2014

      I’ve been reporting on the story for a while now. Mushrooms and seaweeds seem to soak up radionuclides like sponges. What’s really pissing me off is restaurants outside of Japan selling dishes made with potentially contaminated ingredients, including Japan’s fish.

      Japan’s system of monitoring leaves lots of power in the hands of the locals, not the feds. That, too, is disturbing.


      For more on tea, see

      Could somebody tell me how to create hyperlinks in these comments?

  • Darryl

    I’m not convinced by the Mangano & Sherman paper ( economic factors like foreclosures were hitting hard in the U.S. at the time ).

    As xenobiotic hormesis appears to be an important mechanism for disease prevention by whole plant based diets, I think its worth perusing the extensive literature on its academic predecessor radiation hormesis ( ), as a number of cellular mechanisms are shared. A worthwhile summary presentation: As its a difficult argument I don’t expect hormesis to appear in mainstream sources in the near-term, but I believe I’m far from the first health oriented vegan to find the subject fascinating.

    • Coacervate

      iS your brother named Darryl?

  • LumLum2500

    I worry more about the cosmic radiation Dr. Greger is exposed to during all his plane trips!

  • Pandabonium

    The “study” you cited about infant deaths is more than controversial, it is downright shamefullly bad science. As Michael Moyer pointed out in Scientific American, if they had not just compared deaths in the four weeks prior to the Fukushima Daiichi accident and rather had gone back to the beginning of the year, they would have discovered that infant mortality had actually declined. Not saying that the accident wasn’t bad or dangerous (I live only 100 miles from the damned thing!) but that study was not at all scientific and IMHO does not deserve to be referenced here.

  • LynnCS

    I was going to ask about seaweed and other Japanese foods too. I like a lot of the macrobiotics type foods from Japan.

  • Osher

    When I was a child, my mother would take me to Buster Brown Shoes. Back in those days, I climbed up on this boxy thing and had my feet x-rayed. 65 years later, I’m wondering whether I’m going to get cancer of the feet.

    • hahahehe

      that’s the funniest comment i’ve read for a long time anywhere. I remember standing in line at a school and being given a pink sugar cube of polio vaccine, we all thought it was so wonderful. And we all had a huge scar on our upper arm near the shoulder from the ugly small pox caused by those immunizations. My scar is still visible.

  • Ji Kang

    Hi Dr. Greger, first of all I like to thank you and your staff for doing such a wonderful job informing the public on nutritional health.I’ve got a question and wondering if you have any opinion or answers to them, your time is greatly appreciated. I’ve noticed you’ve placed a great deal of emphasis on eating and incorporating green leafies in our diet for optimal health, however with the recent years fukushima catastrophe, could you give us any real information on how safe consuming these broad leaf vegetables really are, especially if you’re near the west coast, there seems to be so much misinformation out on the internet there is much confusion. I try to adopt healthy eating habits for my family, and I spread the vegan gospel, whenever I can, to my friends and community alike, but I’m particularly concerned for children bc they’re more vulnerable due to their growth development. Thank you

  • Arjan den Hollander

    LOL 120 – 138 lung cancer deaths per year per 1000 smokers!

    Not a single person would smoke and not a single siggarette would be sold if it were anywhere near those numbers. That’s just a complete fabrication those numbers.

    I would be dead 3 times over as would half the people who smoked for 4 years. This is clearly not true as most smokers only start showing irreversable debillitating signs of damage after decades of smoking.

    I got a lot of respect for you Dr. Greger after watching numerous usefull video’s, problem is always that reputation is lost faster than it is gained.

    This just shreds your reputation quoting obvious nonsense, you should remove this video or at least the quoted smokers research bit. Since its clearly fuzzy math and done or written by chimps.

    I’ll be watching out for disinformation in your video’s a lot more keenly from now on, as you are degraded from guru to meer mortal :)

    Regards, Arjan den Hollander.

  • Harriet Sugar Miller

    In that table on polonium concentration in surface seawater, to what degree do the differences in numbers matter?

  • Greg

    Dear Dr. Greger,

    I am concerned about the Fukushima radiation effecting California farms. Most of the berries and vegetables my family consumes are grown in California, near the Pacific Ocean. I would like to know if our foods contaminated by radiation? Organic or not aren’t all farms exposed? Are there any studies on matter?

    I haven’t found any solid evidence but there are alarming articles online about the situaiton: