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The purpose of this diary is to provide new information reported by a Canadian led effort to determine the timing of the arrival and the concentrations of Fukushima sourced radionuclides in ocean waters off North America.  Since 2011 measurements of Cesium(Cs)-137 (half-life ~30.1 yr) and Cs-134 (half-life ~2 yr) have been made in the north Pacific and Arctic Oceans.  Most recent measurements show that Fukushima derived Cs has reached the west coast as of June 2013 by ocean transport but that concentrations of Cs continue to be well below levels thought to pose environmental or public health threats.

There have been a number of popular press articles that have summarized the results of this program as reported in a presentation at the PICES – North Pacific Marine Sciences Consortium meeting held in Nanaimo, BC Canada in October 2013.  Most of these report the timing of the arrival of the radionuclides but offer no perspective on the actual levels and the associated risk to residents of the west coast (e.g. link).  The presentation is available online here and represents the work of Department of Fisheries and Oceans scientists working in the North Pacific and the Arctic Oceans. The raw data summarized here can be found in the presentation.

It is a useful exercise to first familiarize ourselves with some of the units that scientists use when discussing radioactivity. A commonly seen unit is the Becquerel (abbreviated as Bq), which represents an amount of radioactive material where one atom decays per second and has units of inverse time (per second). Another unit in common use is disintegrations per minute (dpm) where the number of atoms undergoing radioactive decay in one minute are counted (so 1 Bq = 60 dpm). When we talk about the radioactivity measured in seawater the measurements are reported normalized per litre of seawater (Bq/L).

In previous diaries I have presented a primer on the major contributors to radionuclide concentrations in average seawater and discussed other aspects of radionuclide behavior in the ocean.  About 93% of radioactivity in seawater results from the presence of primordial, naturally occurring potassium-40 (K-40) and rubidium-87 (Rb-87). The remaining 7% are radioactive elements deposited to the ocean from past atmospheric nuclear testing. The sum of these activities is about 14 Bq/L on average though there are regional differences that scale with ocean salinity.

Ongoing time series measurements are being carried out by the Department of Fisheries and Oceans to determine when and how much radioactivity from the Fukushima disaster will arrive along the west coast of North America.

Results of the Line P Time Series Program thus far can be summarized as follows:
1) Cs levels in June 2011 were consistent with pre-Fukushima levels present from atmospheric nuclear test fallout
2) In June 2012 surface waters ~1500 km offshore had detectable Cs-134 from Fukushima and associated Cs-137 of 0.0003 Bq/L or roughly 0.002% of naturally occurring background radiation
3) Fukushima derived Cs was detected all the way to the coast in June 2013 with the highest levels of Cs-137 farthest offshore (0.0009 Bq/L or roughly 0.006% of background radiation) and lower levels of 0.0003 Bq/L toward the coast.
4) The timing of the arrival of the plume agrees with the modeling study of Rossi et al. (2013) published in the peer-reviewed journal Deep-Sea Research (link) but the concentrations are lower than predicted

Ongoing monitoring will constrain the likely environmental and health risks posed by ocean transport of Fukushima derived radionuclides.  

Originally posted to MarineChemist on Sat Jan 04, 2014 at 02:14 PM PST.

Also republished by Koscadia and SciTech.

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Comment Preferences

  •  Thanks for your work (3+ / 0-)
    Recommended by:
    Roadbed Guy, thomask, Rogneid

    We are all doomed by the 0.006% increase.

  •  Just to ask.... what about the accumulation (7+ / 0-)

    effect in ocean life like with mercury?

    •  Hi My suncatchers (3+ / 0-)
      Recommended by:
      wilderness voice, Lujane, Wee Mama

      At these concentrations bioaccumulation of Cs will be quite small. Potentially significant levels are found in organisms seeing much higher concentrations proximate to the Fukushima site in the western Pacific.  See my earlier diaries for measurements of radionuclides in commercially important fish like Pacific bluefin tuna.

    •  A report from 2003... (5+ / 0-)

      Looked at bioaccumulation of cesium-137 off Norway, from krill and amphipods at the low end of the food chain to harbour dolphins at the top end.  They measured Bq per kilogram of animal compared to Bq per liter of seawater (which is about 1 kilogram in mass). A ratio of 1 meant that you were getting the same number of Becquerals out of the animals that you were getting out of a roughly equivalent mass of seawater.

      At the low end (krill and amphipods), the cesium was concentrated at levels 7 to 13 times that of seawater. At the upper end, it was about 160-170 times, so as a rule of thumb, you could assume that the upper end of the food chain would be 10 times more concentrated than the low end.

      At this point, before people start screaming in panic, the important question to ask is "concentrated compared to what?" As people keep pointing out, a hundred times a miniscule amount is still a very small amount.

      Five hundred (500) Bq/kg has generally been considered the limit allowable for food under regulations used all over the world (Japan has since dropped it to 100, mostly for PR reasons, to be honest). In the Norwegian study, even the highest end of the food chain was under 1 Bq/kilo.

      So if you assume the upper end of the food chain (sharks, whales, tuna) will concentrate cesium, to be liberal, at 200 times its level in seawater (based on the results of the aforementioned study), and using the high levels of 0.0009 Bq/L mentioned, that means the tuna will be at 0.18 Bq/kg more than what they'd have otherwise. Or 0.18% of the limit under the Japanese regulations and 0.036% of the limits generally used in other places.

      Not exactly "Ohmigod we're all gonna die and the Pacific Coast is going to turn into a post-apocalyptic radioactive wasteland!" levels we're talking about.

      •  Given the choice between cesium laced fish (1+ / 0-)
        Recommended by:

        And clean fish.

        I bet dollars to donuts the great majority would choose the clean fish.

      •  Minuscule amounts of exposure have been shown (3+ / 0-)
        Recommended by:
        Duckmg, Lujane, Creosote

        to be a risk to health and life. Not a guarantee of damage, but certainly a risk. As of today there is no known safe level of exposure to radioactivity, and all the official 'safety limits' are statistical-based guesses of risk in light of wanting to make money on one thing or another. (Personally, I think it unlikely that money and power doesn't influence what assumptions are made in many 'scientific' studies. There's a long and rich history on that topic.)

        Moreover, a unique risk of damage occurs with each exposure. Eat the minuscule-risk fish, and have the famous banana for desert, and do it on an airplane, after you cleaned out your 'normal background level' basement, and left your neighborhood with the emitting reactor ... well, how many times do you pull the trigger and the chamber is empty?

        Again, C-137 is only one of the radioactive elements in play.

        I imagine the true test of Fukushima's impact will be if we start seeing massive instances of sea life species presenting symptoms of radiation poisoning.

        Actual Democrats: the surest, quickest, route to More Democrats. And actually addressing our various emergencies.

        by Jim P on Sat Jan 04, 2014 at 06:21:24 PM PST

        [ Parent ]

        •  I love that meaningless expression (1+ / 0-)
          Recommended by:
          joseph rainmound

          "there is no known safe level of exposure to radioactivity"

          Well, you know what? Life bloody well evolved in radiation, radiation surrounds us everyday from 100% natural sources, so the idea that there's "no safe level level of exposure" is about as useful a statement as saying "There's no guarantee you won't be struck dead by a random event in the next 30 seconds."

          Do you spend your life in a constant panic because in the next 30 seconds a plane could crash into your house, a rabid wolf could attack you, you could get hit by a bullet fired a mile away by an errant shooter at a gun range, or any number of other highly improbable events which demonstrably have happened to people?

  •  I'm looking for stuff like this (1+ / 0-)
    Recommended by:
    Wee Mama

    Check your messages for a private message.

    © Tomtech! My comments may not be used without my permission outside of the post which it is posted in..

    by Tomtech on Sat Jan 04, 2014 at 03:33:41 PM PST

  •  Thanks. Measures of Strontium, Plutonium, (4+ / 0-)
    Recommended by:
    Bisbonian, Joieau, Lujane, Creosote

    and the other radioactive elements released from Fukushima are still forthcoming, I presume.

    Do these studies also account for wind-borne radiation which reaches North America's West Coast?

    Has any research been done on bio-accumulation in sea life on this scale yet? It seems bigger fish live from 10-30 years, so I guess it'll be awhile before we know. From what I can find, there doesn't seem to have been much study on how radiation affects sea life in terms of their health. Might you know of any extensive studies on that topic?

    And given the half-life of the isotopes, what might the figures of Cs-137, Plutonium, etc be in the optimistic scenario of Fukushima remaining a source of new pollution for only another 30 or 40 years?

    Finally, just an observation: humanity has added 7% radioactivity to an Ocean after only 60 years or so! It took nature the life-span of earth to contribute 13 parts, and we've added 1 part in just my lifetime. Quite an amazing feat, when you consider it.

    Note that it's likely not just atmospheric testing of bombs which contribute to that 7%, as it seems everybody with a reactor has been dumping waste into the waters of the earth. Or have those not yet broken through their steel containers?

    Actual Democrats: the surest, quickest, route to More Democrats. And actually addressing our various emergencies.

    by Jim P on Sat Jan 04, 2014 at 04:16:51 PM PST

    •  Hi Jim P (8+ / 0-)

      Based on measurements of their release at the reactor sites the concentration of Sr-90 is expected to be ~3% of Cs-137 (Casacuberta et al. 2013 Biogeosciences). Estimates based on isotope ratios of Pu in the environment following the disaster suggest that between 0.00002-0.002% of ~6kg of Pu in the reactors was released to the environment (Schneider et al. 2013 Nature).  Their concentrations will likely be near detection limits in the eastern Pacific. Measurements of Sr-90 and Pu are more analytically challenging than Cs isotopes and take more time to process especially at these levels.  

      A good place for information on actinides and other radionuclides in marine organisms is Dr. Nick Fisher's website and research group at SUNY-Stony Brook (link). There is a wealth of information about how concentrations and uptake of isotopes affect the growth and metabolism of marine organisms.

      If you read some of the articles in this very well put together, open-access edition of Biogeosciences on Fukushima (link) you will find numbers as to the contribution of waste dumping and fuel reprocessing to the 7% anthropogenic load.  Table 1 in Povinec et al. 2013 provides the following information:

      Cs-137 Total fallout in ocean/waste discharge = 15
      Sr-90   Total fallout in ocean/waste discharge = 54

      Cs-137 Fallout present in 2010/waste discharge = 6.5
      Sr-90   Fallout present in 2010/waste discharge = 35

      Many fold more background Cs and Sr radioisotopes are present in the ocean from atmospheric testing than is present from fuel reprocessing and waste discharge.

  •  Thanks, MarineChemist (4+ / 0-)
    Recommended by:
    Kasoru, Lujane, Wee Mama, alx9090

    Thank you for this thoughtful, non-alarmist presentation.

  •  There is also this: (0+ / 0-)
    At 0:30 in

    Beverly Thompson, Host: These numbers are just staggering.

    At 1:15 in

    Gordon Edwards, Court-qualified nuclear expert and president of the Canadian Coalition for Nuclear Responsibility: The average concentration in the fish, the average concentration of radioactive cesium has gone up considerably.

    At 4:00 in

    Edwards: Canadian authorities and the global authorities are really doing us all a disservice by not following and monitoring this much more closely. They’re treating this as though it’s kind of a ho-hum situation, but in fact, it’s a major event worldwide and it should be studies very carefully [...]

    Thompson: They are certainly staggering numbers.

    •  8 cancers per one thousand people exposed (1+ / 0-)
      Recommended by:

      Over a seventy year period.

      •  Hi Duckmg (3+ / 0-)

        Here is the link to the article that they discuss on CTV news (link).  It is a piece by Alex Roslin published in a local paper called The Georgia Straight. It appears that Roslin used an online cancer rate formula provided by the EPA but there are no details provided.  In fact the portion of the story where the 1 in 8000 figure might be is missing from the online version:

        But the radiation detected can still cause cancer, according to the U.S. Environmental Protection Agency’s cancer-risk formula, a leading international standard for forecasting cancer risks from radiation. The

        What’s more, the EPA formula underestimates cancer impacts because it doesn’t fully include all research on radiation impacts, in the estimate of Daniel Hirsch, a UC Santa Cruz nuclear expert.

        It is really difficult to determine where that number comes from and how useful it is.  Tuna with similar levels of Cs-137, consumed at dietary intakes greater than North American average would lead to a increase in cancer rates of 2 in 10,000,000 according to Fisher et al. 2013 PNAS.  This assumes a excess relative risk of fatal cancer of ~5% per Sv of radiation dose.
    •  Hi Duckmg (0+ / 0-)

      There are high Cs-137 levels in fish in the western Pacific as this interview with Gordon Edwards reports.  Fish with 18 Bq/kg Cs-137 would still expose consumers to 100's of times more radiation from naturally occurring Po-210. I will have to track down the study where they calculate 8 in 1000 cancers in those exposed.  Do you have the link?  It seems rather high.  I wonder what consumption rates they estimate for example.

      The concentrations of Cs-137 in waters expected here on the west coast will no likely not result in concentrations approaching 18 Bq/kg in commercial fish.  The levels offshore and inshore are 10,000 to 33,000 times lower than the drinking water allowable levels of 10 Bq/L Cs-137 (Drinking Water Standards - Canada).

  •  Thank you (0+ / 0-)

    for dispelling much of the junk science surrounding this extremely important on-going issue. The alarmist crap is worse than 'aliens among us' but not quite as bad as 'chemtrails'

    Please keep writing.

  •  Do they serve North Pacific fish (1+ / 0-)
    Recommended by:
    Friend of the court

    at the Japanese PMs residence?

  •  Update on Fukushima Radionuclides (0+ / 0-)

    Once again Jay Cullen is comparing external sources of radiation like x-rays to internal sources of radiation which have a very different effect on the body.  This is an argument and line that is s consistently being peddled by those whom I believe,  are using a false analogy of external radiation sources and comparing it to internal ingested radiation.  They also falsely employ comparisons of bananas to to cesium.  While bananas leave the human body, cesium stays within the muscles of the human body.  In my opinion this comprises tortured science.

    A Japanese professor answers these arguments in a long letter he wrote urging parents not to send exchange students to Japan because of the widespread nature of food contamination there.

    The same thing that holds true in Japan holds true elsewhere as  Russian scientist recently warned.  You cannot test and check entire catches of fish.  And fish is coming from all over the ocean.  Heavy elements and metals deposit in ocean sediment.  These fish and shellfish can have higher levels of cesium, strontium 90 and other heavy elements and metals like zinc.

    Another issue  Cullen bypasses altogether is strontium 90, plutonium and other radioactive  elements that have been released into the ocean for which there have been no studies done.    It is very difficult to check  for strontinum 90.  The Japanese have reported it takes a month to do an entire test so they don't do it as often on their fish catches. But yet much of the leak material flowing into the ocean is now strontinum 90 although it is a lower amount than cesium and could t ake much longer to reach the West Coast.

    Also, the amount of radioactivity in seawater is not necessarily a measurement of the amount of radioactivity in either ocean sediment or ocean fish. I'dlike to know the specific places that seawater was checked and if other checks were made as well and ocean sediment and varoius kinds of bottom dwelling fish.  

    Jay Cullen is a marine scientist, he is not a physician or medical  doctor.  I don't believe he can prescribe what is or what is not say, he can only offer an opinion. Meanwhile, the EPA and FDA have both acknowledged that there is no safe level of radiation.

    More recently, a very large epidemological study of thousands of radiation studies was done by a Cambridge researcher and reported in Science News Daily.  This research concluded there is no safe threshold of radiation.  This research follows other large epidemological studies now being made.

    Jay Cullen quotes Nicholas Fisher in a previous statement he submitted to a newspaper in British Columbia which did  not print various letters to the editor which were submitted in rebuttal.  Nicholas Fisher, too, is worried about the "alarmist nature" of the press he states in a research article he published last year. In this article Fisher holds out t he Health Physics Society as an organization which states we shouldn't be concerned about radiation. The new President of the Health Physics Society is an individual who worked at the Pacific Northwest Laboratory, a DOE lab on the Hanford radiation studies commissioned by the Center for Disease Control. This study was commissioned to study thyroid disease and other illness of  the Hanford and Washington victims of the goverments secret  release of readioactive iodine C131 done in the Cold War period when the Human Radiation studies were secretly conducted.  The study concluded there was no real link between the thyroid cancer found in the victims and the government's release of iodine.  The President of the Health Physics Society worked in the lab that produced this report.  There was a huge hue and cry over the report which was withdrawn and had to be redone after it was critiqued for having underestimated the amount of radioactive iodine released by 3 times.  The report cost us $14 million.  Other scientific results which disagreed with the conclusion were burried in the report and the research had to be  redone by the CDC.  Meanwhile, they found many participants in the study who they later contacted had died at a level of 20% higher than the general p population.

    All these researchers are tied together in my opinion from what I have seen  by politics.   Their positions and arguments are not free of their political beliefs.  If a person takes the time to investigate more closely, you sometimes find they are linked directly to the Defence policy of the US government and the political  line of the present US administration which is pushing nuclear power heavily.  No surprises as the nuclear industry was oneBarack Obama's biggest campaign supporter.   Obama continues the policy only interrupted briefly by the Clinton administration,  not to release studies about the effects of radiation on humans. That is why most of the secret Human Radiation studies done by higher universities as well as the CIA, remain classified for decades still.

    •  Hi torturedscience (0+ / 0-)

      This is a very aggressive post. I stick to reporting the data being collected in the ocean and marine organisms.  I compare this data to established public health guidelines, for example drinking water standards, to gauge what health risks the people living on the west coast might face. I have never presented myself as a medical doctor so I am not sure why you mention that in your post (my handle is MarineChemist which I think makes my training rather obvious). My goal is to report what we know about radionuclides from Fukushima in the marine environment and to help put the risk in perspective.

      You can see where all of the data mentioned in this post was collected and all the other references I provide by following the links and reading them.

      Can you tell me what "low levels" of radiation led to the negative health impacts in the Cambridge study you cite? The paper in question is Moller and Mousseau 2013 Biological Reviews as reported on by Science Daily News.  You say

      More recently, a very large epidemological study of thousands of radiation studies was done by a Cambridge researcher and reported in Science News Daily.  This research concluded there is no safe threshold of radiation.  This research follows other large epidemological studies now being made.
      If you read the paper they actually consider 46 studies and not thousands. They are detecting effects using meta-analysis at exposures of 0.01-0.1 Sv.  These levels are orders of magnitude higher than a North American would be exposed to by choosing to consume ~25 kg of contaminated tuna in a year.  That is internalizing fish with ~10 Bq/kg Cs-137.

      I can't speak to any of your theories of conspiracy or political meddling in science and science funding.  You should really lobby your government to support high quality work like Buesseler's and to provide a solid monitoring program so that we know what is happening along our shared coast.

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