Cesium and cobalt-60 in US Pacific coast seaweed.

SimplyInfo has a new item about radioactive contamination of seaweed off Washington state:

New testing done by Worcester Polytechnic Institute, Dept. of Civil and Environmental Engineering found Fukushima cesium in US Pacific sea weed. The samples were standardized against a known amount of cesium 137 and cobalt 60. The finding of cesium 134 would indicate this is at least partially from the Fukushima nuclear disaster.

“Washington State Pacific coast eel weed sample contained 0.22 pCi/g of Cs134 and 0.24 pCi/g of Cs137. It also contained 0.1 pCi/g of Co60”
These values converted to the more common bq/kg are:
Cesium 134: 8.14 Bq/Kg
Cesium 137: 8.88 Bq/Kg
Cobalt 60: 3.7 Bq/Kg

I have not been able to get more information as to when the sample was collected and tested, only that this is a “new” test.

The significant thing about this measurement is that the amount of cesium-134 is 92% of the amount of cesium-137. This corresponds approximately to the ratio of 134 to 137 that was found in March 2011. Values of samples collected today contaminated with March 2011 fallout only would indicate 134 levels to be less than half of 137. Therefore this is new fallout.

Caesium-134 has a half-life of 2.0652 years. It is produced both directly (at a very small yield because 134Xe is stable) as a fission product and via neutron capture from nonradioactive Cs-133 (neutron capture cross section 29 barns), which is a common fission product. Caesium 134 is not produced via beta decay of other fission product nuclides of mass 134 since beta decay stops at stable 134Xe. It is also not produced by nuclear weapons because 133Cs is created by beta decay of original fission products only long after the nuclear explosion is over. (Wikipedia)

This would indicate that the seaweed sample has undergone atmospheric contamination from a recently emitted plume, that originated as a result of fission or a criticality.

The presence of cobalt-60 implies a criticality has occurred:

Cobalt-60, 60Co, is a synthetic radioactive isotope of cobalt with a half-life of 5.27 years. It is produced artificially by neutron activation of the isotope 59Co. (Wikipedia)

Cobalt-60 is an activation product which is produced from activation of cobalt-59 by free neutrons.

Again, I do not know the provenance of this result, so take this for what it is worth.

11 thoughts on “Cesium and cobalt-60 in US Pacific coast seaweed.

  1. In utero exposure to cobalt radiation has been extensively studied in animal species, and may elicit substantial effects across many organ systems of the developing organism. Organs known to be affected include the brain, eyes, hair, kidney, liver, ovaries, pituitary, skeleton (including cleft palate, shortened digits, fused digits, and other gross abnormalities), spleen, teeth, testes, and thyroid. 60 Co radiation in utero has also shown to cause functional alterations, including
    postnatal growth retardation, neurobehavioral changes, hormonal production, alterations in hepatic enzymes, and diabetes mellitus. In utero irradiation with cobalt also leads to increased tumor incidence later in life.


  2. I was not able to find out how much cobalt is used in alloys, but common sense tells me it should be a small portion. These numbers of cobalt comparable to Cs are somewhat strange for me.Could this be the explanation:
    “In the marine environment cobalt is needed by blue-green algae (cyanobacteria) and other nitrogen fixing organisms”
    or it is just too much? The same questions torture me about Cs134/ Cs137. Isn`t Sc134 too much in Fukushima, compared with Chernobyl?

    • Fukushima is so much worse than Chernobyl, that it has become meaningless to compare them (in terms of severity). The only thing to compare it to is the atmospheric nuclear tests of the 50s and 60s. The only single bomb you can compare Fuku to is the Castle Bravo blast of 1954, which released 7 times more radionuclides than the Tsar Bomba (biggest nuke blast of all time).

  3. I have been posting for weeks On outside sites your article, sorry if it bring some trolls ! but they are so dumb sometimes they make me laugh lol

  4. I’m curious to know why any info concerning isotopic iodine are neglected.

    Where’s the original press release from WPI?
    Note that the story on simplyinfo has no apparent linked origin.


    Where’s the beef?

    I cannot add my comment to their site without Gravatar’s javascript disabled. They are the one’s that track one’s image associated with username on fukudiary, here, simplyinfo, et al. Note that any post made on fuku-diary has a “snowflake”-like image associated that never changes – that’s Gravatar.

    • Really, wouldn’t radio-iodine be more concernng to those that know the half-life length of I-129?
      Also, would not any I-131 detections be thought-provoking?

      I feel that we have all been robbed of vital data.

      • That’s why I was hedging… at any rate, whenever this detection occurred, cobalt-60 was found. This isotope is nasty, and I haven’t heard about it before in the US.

        • Very true. I am grateful that you have brought this forth.

          It has not been heard of before likely because damn few test for it, and even fewer release candid results.

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