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Wednesday, May 30, 2012

What the radioactive Fuku tuna really mean to us

Here's a good take on the significance of the story we linked to the other day, about radioactivity in tuna being caught off San Diego -- the source of which is unmistakably the triple nuclear meltdown at Fukushima. Bureaucrats in places like Salem will tell you there's no need to worry, but perhaps you should think for yourself:

The various media accounts of the study have included some confusing statements. Statements that the findings are "below limits" or "totally safe" are misleading and confusing as they don’t give a clear understanding of what was found. The US FDA level of contamination... before action is taken is 1200 bq/kg, considerably higher than the Japanese level of 100 bq/kg.... [The fish were back calculated to confirm they originally had cesium concentrations that matched those of bluefin tuna found off Japan that had a rate of 61–168 bq/kg....] While the findings in the paper are low it doesn't mean there is no risk. Eating a piece of tuna from the study won't make someone drop dead at the sushi bar, but it does add to your internal contamination level of a man-made radioactive substance that takes 110 days for half of it to clear your body. Internal contamination is worse than external contamination. If someone is continually eating contaminated food from one or many sources every day it does add up quickly....

Other confusing statements [have been] made in relation to the bluefin tuna paper such as comparing it to an airplane flight or an X-ray. Both of these are external exposures, this is not the same as internal exposure one would receive from eating contaminated tuna. Others have tried comparing exposure to a nuclear accident to eating a banana or Brazil nuts, two foods that contain naturally occurring potassium 40. Potassium 40′s natural abundance is quite low. It also clears the body at a half life of 30 days compared to 110 days for cesium. The specific activity of potassium 40 is 0.0000071 (Ci/g) compared to 1,300 for cesium 134 and 88 for cesium 137. Potassium 40′s radiation energy is 0.52 MeV for beta and 0.16 MeV for gamma. Cesium 134 has a radiation energy level of 0.16 MeV for beta and 1.6 for gamma. Cesium 137 has a radiation energy of 0.19 MeV for beta but also decays into barium 137m that has a gamma energy of 0.60 MeV. Cesium 134 and 137 are not naturally occurring isotopes and have a much different energy and composition than potassium 40. Comparing the cesium found in these tuna to the potassium 40 in a banana is just not an accurate comparison....

These media statements are made to try to shorthand the risk level for the public but they do a horrible job of explaining the risk of food contamination or exposure after a nuclear accident. The study isn't really cause for immediate panic. It does show that contamination higher on the food chain happened much faster than anyone including the researchers had assumed. It also shows the ability for migratory sea life to become contaminated in one location, then travel vast distances to be landed as food. The recently published study by Woods Hole researchers that looked for radiation contamination patterns in the Pacific also resulted in some unexpected findings. Both studies concluded that more testing is necessary to fully understand the impact the Fukushima disaster has had on the Pacific.

The State of Washington is now testing returning salmon for radioactivity. Apparently Oregon is not.

Comments (10)

Gosh you'd think our healthcare-for-all governor would be trying to make sure we know what kind of invisible foe we are up against.

Now we got Polar Bears getting sick:

"Biologists have found Polar Bears in the Beaufort Sea with hair loss and skin lesions. Those are the same symptoms that have sickened ice seals and walruses in the arctic since last summer and led the federal government to declare the incident an unusual mortality event. Scientists are just beginning an investigation into whether polar bears are suffering from the same thing."

Apparently Oregon is not.

Was ich nicht weiß, macht mich nicht heiß.

And this is a problem - why? Apparently, the new tuna cooks itself, so we don't have to use evil "fossil" fuels or "non-renewable" hydro-power to do that. It's Green! It's Sustainable!

Are we making light just for fun or do we really not care?

And what does the German phrase mean above? Unfortunately German is not one of my languages.

I worry about radiation because of its undetectability. This makes it easy, and common, to ignore and cover up.

Then people are sick, kids are born with birth defects, dogs start talking, etc...

I guess if your cat is hyper-thyroid you could feed it some of the tuna, and give it an I-131 treatment for free? I'm not worried all tuna has a little I-131 contamination, and always has - naturally, I just don't know how much. I'm more interested in the activity per serving, the concentration, or volume, or dose, being ingested, rather than the the contamination measurement. In other words, assay the tuna, before we get all excited. This is much ado about nothing.

As far as our salmon goes, does it migrate near Japan, and how long does it take it to get here?

I gotta tell ya Mark. It doesn't matter, or soon won't matter, where they migrate. The food chain is weird and complex. Osmosis and vicinity to Fukushima are not controlling factors. The radiation will pool in the food chain is surprising areas. For example radioactive tuna surprised 'experts'. Same with polar bears.

Do polar bears migrate near Japan?

After Chernobyl, and to this day, the radiation has concentrated itself in wild pigs. I can't find the article but I remember it vividly (while reading about the wild pig explosion in the US...)

Can someone tell me why every time humans screw up polar bears get the shaft?

Sooo is this going to affect my weekly pregnancy splurge at Subway of the tuna sandwich and turn my baby into an X-Men?

Can someone tell me why every time humans screw up polar bears get the shaft?

I assume you're aware of the fact that there are more polar bears today than at any time in recorded history?

Jo - I specialize in radiation measurement instrumentation, and I haven't the faintest idea what you are talking about? I-131 collects and occurs naturally in the Ocean. Here in Portland we have a huge concentrations of Radon Gas that occurs naturally and accumulates in our basements throughout East Portland yet we have no measurable negative effects of increased cancer here in town.

Now if the Tuna, and Salmon have Cesium contamination, then I'm worried. We don't have any contaminated fish in the Columbia with increased levels of Strontium, Cesium, or Iodine from Hanford. I doubt the tuna are an ongoing problem that won't eventually take care of itself.

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