Japanese Nori type Seaweed testing by enviro reporter

Submitted by Anonymous on Sun, 2012-04-22 15:10

Berkeley Radiological Air and Water Monitoring Forum

http://www.enviroreporter.com/2012/04/japanese-seaweed-radiation-doubles/

Big thank you to enviro reporter for this exposé .Looks like some items are slipping through...

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self test

Submitted by Anonymous on Fri, 2013-03-01 00:05.

Can anyone walk into a Ranch 99 or Mitsuwa with a Geiger counter, and give some readings of the shelves with nori?

Is it a blip, or is all this nonsense?

Is ash contaminated Tokyo Bay still a healthier environment overall than aqua-culture off the coast of China with industrial run off?

Won't work with a Geiger counter!!!

Submitted by Anonymous on Fri, 2013-03-01 08:24.

The above poster asks:
Can anyone walk into a Ranch 99 or Mitsuwa with a Geiger counter, and give some readings of the shelves with nori?

A Geiger counter would be USELESS for what you have in mind.

That's because the natural radioactivity of the nori is many times larger than any contamination from Fukushima. All the Geiger counter would see is the natural radioactivity. So you would get the SAME Geiger counter reading whether or not the nori was actually contaminated. You need a system that can do spectroscopy like the Germanium detectors that BRAWM uses.

Mark of BRAWM explained this in this post:

http://www.nuc.berkeley.edu/forum/218/brawm-question-testing-food-geiger...

Geiger counters are rather blunt instruments; they can detect radioactivity but they cannot tell you which isotope is responsible for it. One might detect radioactivity using one of these instruments, but there is plenty of benign natural radiation out there (e.g., where does the 38 CPM of the background test come from?). A Geiger counter would really only be useful for finding contamination in northeast Japan and nowhere else in the world.

Testing

Submitted by Anonymous on Tue, 2012-04-24 20:46.

I'm wondering if BRAWM would consider testing imported products like this nori. Or local seaweeds which have shown contamination.
Thank you

Erroneous measurement. They

Submitted by Anonymous on Mon, 2012-04-23 22:28.

Erroneous measurement. They have no background sample of seaweed. They consider background air to be equivalent, that is comparing apples to oranges.

Seaweed tested right

Submitted by Anonymous on Tue, 2012-04-24 17:08.

Actually, seaweed is recommended by the government and numerous health sources as one of the most effective ways to *detoxify* from radiation exposure, as explained at http://www.healthiertalk.com/seaweed-protection-against-radiation-3581 therefore isn't exactly a plant known for being nuked already. It, normally, has NO ionizing radiation in it. This specious argument also flies in the face of what the California Highway Patrol considers the tripping point for a hazardous materials situation: anything over 3 times background. That would be the ambient air's background in many cases. Once again, the pro-nukers on this site dismiss out of hand yet another important piece of evidence of Fukushima's ongoing and increasing contamination of North America. Next, you'll mimic BRAWN saying 'it's no worse than a plane flight,' which of course is wrong because ingesting alpha and beta radiation is far more harmful than exposure to gamma in flight. It would be a better world if this kind of pompous twaddle were relegated to the dustbin once and for all.

Suggesting someone eat

Submitted by Anonymous on Wed, 2012-06-13 09:15.

Suggesting someone eat seaweed to detoxify does not mean that seaweed that contains harmful materials is in any way safe to eat. It could just as easily be said that eating oatmeal will detoxify you (it is actually far better) but suppose that oatmeal were grown on soil that contained a high level of radioactive materials? It would now be a good accumulator of radioactive materials from the soil and the oatmeal you cook from it will contain high levels as a result.
Foods that have high levels of water soluble fiber in them are the foods that 'detoxify'. What that means is matter in the intestines will be held in suspension in this fiber and will pass through and out. The soluble fiber forms a gel as it travel through the intestines trapping substances such as cholesterols and this gelatinous liquid is the reason for the detoxifying effects.
But suppose Cesium is present in the seaweed or oatmeal? Then that cesium will be assimilated by the body anyway just as if it were a nutrient. The liquids in the fibrous mass are what the intestines draw nutrients from, not the solids, and cesium is mistaken for potassium by our bodies. So it draws the cesium in as if it were potassium and deposits it where it needs potassium.
In order for any detoxifying agent to be effective it must be free of any harmful materials. Seaweed will help ONLY if it is uncontaminated.
On a side note, seaweed can be helpful but the Japanese diet, as rich as it appears to be in seaweed, is not sufficient to do the job because they consume large amounts of rice with the seaweed and this negates any benefits.
Were someone to eat a large amount of seaweed with each meal then it will become effective.
A bowl of oatmeal in the morning or an apple, raw baked, or stewed will be far more effective.
The old saying, 'an apple a day keeps the doctor away' is a truism based on the extremely high amounts of soluble fibers in an apple, perhaps the perfect food to provide these fibers with oatmeal as the second choice.
Any food high in soluble fibers would be excellent to eat for 'detoxification' if you ate a sufficient amount every day (and with every meal!)
But it all depends on them being free of harmful materials to begin with!

Seaweed is naturally radioactive

Submitted by bandstra on Thu, 2012-04-26 13:05.

You said:

It [seaweed], normally, has NO ionizing radiation in it.

That is untrue. All foods are radioactive. Foods contain potassium, which means they contain the primordial radioactive isotope ⁴⁰K. Foods can also contain ²²⁶Ra and other ²³⁸U and ²³²Th decay products. This means food naturally has alpha, beta, and gamma emissions. As a reference, please see the UNSCEAR Report 2008, Annex B, particularly paragraphs 86, 87, 95, and 96; and Table 12.

Taking one company's roasted nori nutritional facts, we find that roasted nori has about 50 milligrams of potassium in each 2.1 gram sheet. Using this to calculate the activity of ⁴⁰K in the sheet, we get 1.6 decays per second per sheet, or about 740 decays per second per kilogram (Bq/kg). This is about the same amount of ⁴⁰K activity that we detected in the dried nori that we tested from the Northern California coast last May — on the order of 1,000 Bq/kg. At the same time, using gamma-ray spectroscopy we were able to identify the activity of the isotope ⁴⁰K and rule out radioactive isotopes from Fukushima to a very low level.

It is not clear how many sheets of nori were tested by that website, but one could easily stack up enough sheets to detect betas and gammas from ⁴⁰K at levels well above background.

To see how radioactive potassium is, please see my simple measurement of a canister of potassium chloride purchased at a grocery store — that canister comes in at 14 times background. It is not a radiological hazard, and it is not radioactive because of Fukushima.

Also, the "detoxifying" effect from seaweed is based on the iodine content of seaweed. Taking iodine supplements (e.g., in the form of seaweed or KI) can decrease the uptake of ¹³¹I by the thyroid if one is being exposed to dangerous amounts. It has no effect on any other radioactive isotopes such as ¹³⁷Cs.

Mark [BRAWM Team Member]

Seaweed absorbs all

Submitted by Anonymous on Fri, 2012-06-15 08:43.

Seaweed absorbs all radioactive elements, not just iodine, very easily and stores them. Japan has ordered the burning of the tsunami debris and it is known to be contaminated with Cesium, etc from Fukushima. also the Japanese Govt has ordered the dumping of the ashes of this debris into Tokyo Bay in order to get rid of it. This started many months ago and is ongoing. Most people are not aware that the overwhelming majority of seaweeds used in cooking, (including at sushi bars around the world) are grown commercially in TOKYO BAY!
Detoxification from seaweed refers to its absorptive qualtities, not from the iodine in it. seaweed forms a gelatinous substance, that holds waste solids, bacterias, etc and allows them to be evacuated readily when you move your bowels. However, we absorb our nutrients from this mass as well and, if it contains things like cesium, we will take them in.
Iodine does not detoxify, but it is needed for our health. making sure that the iodine supplement you choose contains safe iodine, not one of the harmful iodines, such as iodine-129 which is known to have been leaking from the reactors at Fukushima. If you do not have sufficient iodine in your diet then your body takes it from wherever it can and, if that source is a radioactive one, you will take it in and the distinct possibility of a thyroid cancer developing occurs. So you need iodine from a known, good source. Japanese seaweed is no longer a valid source.
A good detoxifying agent is one that is free of harmful matter to begin with and in high in soluble fibers. Normally, I would recommend seaweed but not under the circumstances that exist for the Japanese (or anyone, anywhere, that wonders about using seaweeds from japan.
America = eat apples! :)

I have Nori that can serve as a background sample.

Submitted by Anonymous on Thu, 2012-04-26 14:24.

Hi. Anticipating heavy Pacific contamination from the FDNPP crisis, I purchased quite a bit of nori last year, on the weekend following the explosions - on March 18 and March 20 to be exact, from a store in Phoenix. I still have several packages, and just ran a 10-minute count using the same instrument used by Enviroreporter, a MedCom produced Inspector Alert Nuclear Radiation Monitor that detects alpha, beta, gamma & xray.

My nori is Yamamotoyama brand, "Sushi Party," toasted seaweed (hand roll size). The best by date is August 24, 2011. As comparison to Mark's purchased nori, the listed potassium per 3 gram sheet is 40mg.

This is a newly opened package (still fresh and yummy - accolades to the manufacturer), and I used 5 stacked sheets on a paper plate, with the detector suspended approximately .25 - .5 inch above the samples for a 10 minute count.

I took 2 background counts - one immediately before and one immediately after the sample count. The 10-minute background counts were 375 and 382 counts for a 10-minute period. The samples were unshielded, so the counts would reflect all emitters - alpha, beta and gamma.

I took a 10-minunte count of the nori, which was 484. This is 102 counts (26.7%) over the higher background.

The manufacturer lists a 15% margin of error for the machine.

So, notwithstanding any anthropogenic radiation from pre-Fuk contamination that may be in this nori, this pre-Fuk nori certainly does contain radioactivity above the room/sampling location background. HOWEVER, the counts from this nori were significantly less than the Enviroreporter's samples, both of which were post-Fukushima.

So, yes - nori/seaweed does contain radioactivity in its natural state, and yes, Japanese seaweed is showing significantly higher than natural background radioactivity post-Fukushima, indicating contamination from the fall-out that went into the ocean and/or from the water releases.

Although I have not purchased anything from Japan post-Fukushima, in the interest of science I will (unhappily) pick up a package of this same brand of nori so we can have an apples to apples comparison. I'll run a fresh count on both and report back.

Incidentally, I've got photos of the product packaging, best-buy date and the date/time-stamped geiger counts. I've also got what I haven't eaten of the actual nori in hand still.

What happened here?

Submitted by Anonymous on Fri, 2012-10-19 15:31.

I was interested in this but there's been no update for a long while. Did this conversation move elsewhere?

Cheers,
The Internet

Yamomotamo seaweed

Submitted by Anonymous on Tue, 2012-06-19 16:27.

My sushi restaurant tells me Yamomotoyama brand, though Japanese, is actually harvested and processed in China. Based on that, I was feeling safe eating it. Any thoughts? What were you final findings about the radiation in the seaweed post-Fukushima?

Background CPM versus sample CPM - level of safety

Submitted by Anonymous on Tue, 2012-06-12 19:30.

MM,

If someone claims to have taken background samples of 38 CPM and tested food at 55 CPM, is that food safe?

I'm not an expert, and neither is he, but do you subtract test subject from background? (55 CPM minus 38 CPM to get 17 CPM in food sample). If so, would 17 CPM be safe or is any number above background unsafe?

At what level of CPM over background be cause for concern?

You see lots of stuff on the Internet and hear stuff from people. Thank you for your input.

-just curious

Excellent measurement work, MM

Submitted by bandstra on Thu, 2012-04-26 15:51.

Excellent measurement work, MM. Thanks for sharing.

The exact count rate that is measured will depend on how many sheets of nori are tested. In your case you tested five sheets, each weighing 1.5 grams each. You saw about 100 counts over background in 10 minutes, or about 10 counts per minute.

As far as I can tell, they measured an excess of about 37 counts per minute from their samples, but it is not clear how much seaweed they were testing. This is a very crucial detail. With more sheets, the excess countrate would increase nearly proportionally with the total mass of the sample (some betas will be stopped in the extra layers of material). I would also expect some variability in the potassium content of seaweed, so the measurements may not end up matching exactly even under nearly identical conditions.