Japan Experts: Contamination from Fukushima “is almost irreversible” in coastal sediments

Published: November 17th, 2012 at 12:56 pm ET
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Title: Sedimentation and remobilization of radiocesium in the coastal area of Ibaraki, 70 km south of the Fukushima Dai-ichi Nuclear Power Plant
Authors: Shigeyoshi Otosaka and Takuya Kobayashi, Research Group for Environmental Science, Japan Atomic Energy Agency
Date: 13 November 2012

[...] it can be inferred that dissolved radiocesium advected southward from the region adjacent to the 1FNPP and was deposited to the sediment of the study area in the early stage after the accident. The incorporation of radiocesium into sediments was almost irreversible, and higher concentrations of 137Cs were obtained from the finer-grained fraction of sediments. [...]

137Cs levels in sediment decreased considerably between June and August, and then remained at the same level until January 2012. This trend indicates that the initial deposition of 137Cs to the sediment had almost ceased by August, and that the incorporation of 137Cs into sediments was almost irreversible. [...]

In conclusion [...] it can also be inferred that the remarkable decrease in 137Cs level between June and August 2011 (Table 3) was not caused by dissolution of labile 137Cs but by a physical transport (export) of irreversibly bound 137Cs.

[...] Most of radiocesium in the coastal sediments is incorporated into lithogenic fractions, and this incorporation is almost irreversible. Accordingly, the biological availability of sedimentary radiocesium is relatively low, but continuous monitoring of radiocesium inmarine biota is highly recommended because significant amounts of radiocesium have been accumulated in the sediment.

Published: November 17th, 2012 at 12:56 pm ET
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22 comments

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22 comments to Japan Experts: Contamination from Fukushima “is almost irreversible” in coastal sediments

  • Heart of the Rose Heart of the Rose

    "is almost irrevesible'.
    I have the greatest empathy for those that have to tell these truths..and can barely make the words come from their mouths.
    But..
    The JAEA should say it clearly.

    'Irreversible'
    They need to stick to that word..let them wrap their heads around it..


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  • Jebus Jebus

    H2O and Time causes everything, to eventualy be, at the bottom of the sea…
    The tiny bits, get there faster…


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  • Sickputer

    Otosaka and Kobayashi write: …"Most of radiocesium in the coastal sediments is incorporated into lithogenic fractions, and this incorporation is almost irreversible."

    SP: Rock of Ages… Calcified chunks of cesium that will indeed be irreversible. Leaching poison into the ocean and gaining more daily from fresh leaching deposits surging from the Terrible Triplets (Blobzilla coriums).

    Anybody eating seafood from the east coast or inland waters better keep their wills updated. Or they risk dying intestate.


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  • Anthony Anthony

    Could have also wrote:
    Contamination from Fukushima “is almost irreversible” in North American coastal settlements.


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  • AGreenRoad AGreenRoad

    Meanwhile, the disaster continues around the world, spreading invisible clouds of death and disease for free, to BILLIONS of people

    La Hague; France's Nuclear Waste Nightmare; via A Green Road http://agreenroad.blogspot.com/2012/03/la-hague-nuclear-waste-nightmare.html

    UK Sellafield Nuclear Reprocessing Plant Loses $1.2 Billion Pounds, Then Closes; via A Green Road
    http://agreenroad.blogspot.com/2012/06/uk-sellafield-nuclear-reprocessing.html


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  • There is something a little misleading about the claims made in the article:

    Claim: 137Cs levels in sediment decreased considerably between June and August, and then remained at the same level until January 2012. This trend indicates that the initial deposition of 137Cs to the sediment had almost ceased by August, and that the incorporation of 137Cs into sediments was almost irreversible. [...]

    Problem: No drop in cesium level – contamination continuing:
    Cesium levels in fish off Fukushima not dropping. Aashi Shimbun. Oct 26, 2012
    http://ajw.asahi.com/article/0311disaster/fukushima/AJ201210260047

    [Excerpted] "The (radioactivity) numbers aren't going down. Oceans usually cause the concentrations to decrease if the spigot is turned off," Buesseler told The Associated Press in an interview.

    "There has to be somewhere they're picking up the cesium."

    "Option one is the seafloor is the source of the continued contamination. The other source could be the reactors themselves," he said.

    …Hideo Yamazaki, a marine biologist at Kinki University, agrees with Buesseler's theory that the cesium is leaking from the Fukushima nuclear plant and that it will contaminate seafood for more than a decade.


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    • razzz razzz

      The way I read it, what radioactive sediment doesn't settle and become part of geological recorded history in a (new) radioactive strata layer (to be found by drilling cores or digging through in the future), migrates elsewhere.

      In other words, if they expected to find large amounts of fallout on the ocean floor nearby the Fukushima plant site, and did not find those amounts, it moved elsewhere i.e. floated, storm driven, tidal driven, etc.

      What radioactive amounts they did find are now becoming one with the local ocean floor (concretion).


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    • Radio VicFromOregon

      majia, you are right in that in totality, C137 hasn't gone down and did not drop from June to August. But, in their specific study area, in that particular location, there was a change. They believe that they can extrapolate their findings to the general area. But, as you know so well and have, with others, helped us all to understand, radiation doesn't spread evenly anywhere. It accumulates or carries in varying quantities under varying conditions. I'm not familiar enough with Japan and of where this study was conducted to even guess if it was a good site to choose for making such a generalization as these researchers have. Good catch! Thx.


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  • AGreenRoad AGreenRoad

    the contamination continues from multiple sources;

    fuel fragments thrown out by explosion from #3

    leaking basement water

    coriums underground, interacting with groundwater that flows to ocean

    spills from operations above ground… remember the 60 leaks last winter?


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  • AGreenRoad AGreenRoad

    And some people believe that TEPCO dumped a lot of contaminated stuff and possibly fuel rods in the ocean, just because it is easier and cheaper that way, as they clean up the grounds, SFP's, etc.

    Those huge cranes can swing wide and toss stuff quite a ways..

    It is obvious that no one cares what they do on the site, and there is no one watching up close and personal. Inspectors came and did a dog and pony show and then left.

    The only people who seem to REALLY care are the observers of the webcams


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  • How ignorant have they been in the past?…could be they're using the bad news day of Fuku to bury stuff from other plants?….


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  • kintaman kintaman

    This is not true. It is COMPLETELY reversible. Japan can once again come back to its former pristine state but it will take 250,000-500,000 years to do so. Will we all wait for that time? Will Japan even exist at this time? Will humans still exist on Earth?


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