Goods contamination by radiation

East River

Hello,

Since the Fukushima incident I have wondered if goods manufactured in Japan could be contaminated by radiation. Before posting this thread I have found scattered mentions to this subject in Fukushima threads but I didn't find any clear conclusion on this. I hope not to question about something already discussed.

I would like to know the chances that exports could be contaminated. I'm not talking about food, I'm considering also cars, watches, electronics, etc... is metal more likely to be contaminated? Are there radiation level controls on goods? are they reliable?

Sorry about my ignorance on this subject...

Thanks a lot,

East River

swl

The government falsely claims to have control of radiation levels of goods.
Other than used car shipments being stopped in Russia, the only news I've read is in regard to contaminated agricultural produce.
There are certainly many used cars contaminated with radiation, and I expect that, whole or in pieces, most of them will be exported.

Geiger counters are cheap. Maybe you can stipulate 'no radioactive contamination' in your sales contracts.

Drakkith

Do you have reliable references? I have a difficult time believing this. While no one can control 100% of radiation levels, claiming that the government has no control is flat out wrong.

I feel compelled to point out the fact that we are surrounded by natural radiation every day of our lives. As such, there is effectively no way to enforce this "no radioactive contamination" policy, as a sensetive enough device will always detect some sort of radiation. Given the fact that different types of particles emit different types of radiation, I also don't believe a simple geiger counter would even be effective in the first place in detecting all contamination. Also it is exceedingly unlikely that any contamination would result in large increases in exposure compared to the background level.

Many of these articles claiming to detect radiation in agriculture products are detecting levels so low that you can exceed those levels by flying in an aircraft.

nikkkom

Government? Lying? Can't be! :D

But it's kinda easy to detect that something is wrong when said device starts showing that gamma levels are increased by an order of magnitude near some goods, isn't it?

Caesium is the most easily dispersed contamination, and it *is* a strong gamma emitter, so yes, "simple geiger counter" is a fairly effective at detecting contamination: anything contaminated with Sr-90 (pure beta), plutonium (alpha), etc will be surely also contaminated by Caesium and therefore will emit lots of gammas.

You base this conclusion on what exactly?

Drakkith

I could claim the reverse. Government telling mostly the truth?! Can't be!

Only in severe contamination.

Even if it is effective, the average person has absolutely no clue how to use a geiger counter correctly and would probably panic at any reading. I simply don't think that it would be an effective tool for the OP.

Probability.

nikkkom

x10 background level is not a *severe* contamination.

IIRC, the *natural* variability of background radiation from place to place is about x3. The most naturally radioactive place on Earth in Ramsar, Iran, has natural background radiation one hundred times higher than average.

nikkkom

Well, you might be right about it, as average person is, unfortunately, dumb.

But one doesn't have to be a genius to be able to notice that counter usually shows N counts per minute, but when you bring it close to this particular Japanese car, it starts to show 10*N counts per minute.

swl

Keep in mind that sampling of miniscule amounts of produce can only detect a miniscule amount of contaminated goods. The government claims it is too expensive and that they don’t have enough equipment for testing all of the food. In that case, I suppose even a statistically insignificant sampling plan is better than nothing.

All links are in Japanese. I'm not aware of these issues being reported in the English MSM. Use google for a poor machine translation if you don't read Japanese.


Radioactive beef eaten by children in school lunches at 296 schools over 12 prefectures of Japan. The sale and consumption of contaminated products is not limited to adult plant workers at dai ichi. Samples of the meat tested after consumption was suspended tested over 1200Bq/kg. The government claims that the amount of contamination is small and won’t affect the health of the children. FYI, at most public schools in Japan, consumption of entire school lunch is mandatory, and children are not permitted to bring their lunch from home.
http://www.asahi.com/special/10005/TKY201108100664.html


Ibaragi prefecture, located south of Fukushima prefecture, was contaminated by fallout from the meltdowns. An operation (farm?) in Ibaragi prefecture that grows sod (grass turf) sold their contaminated sod to a nursery school located in Akita prefecture. Neither the governments of Akita, Ibaragi nor Fukushima were able to prevent the shipment and planting of this contaminated sod at a distant nursery school. The silver lining to this radioactive cloud is that they were able to reduce radiation levels at the nursery school by digging up the contaminated sod and removing it.
http://www.yomiuri.co.jp/e-japan/aki...YT8T01135.htm?


Leaf compost sold by Cainz Home centers found with contamination over 14,000Bq/kg. The contaminated compost was sold to customers in Nagano prefecture and also used by children for planting flowers at public schools.
http://www.pref.nagano.jp/nousei/nou...p/fuyoudo3.htm


Contaminated beef exceeding 500Bq/kg was sold in 21 prefectures. Beef sold in Osaka measured as high as 4350Bq/kg and beef sold to, and stored in the home freezer of, a customer in Kochi prefecture measured 2710Bq/kg. Kochi and Osaka are both quite far from the Fukushima plant where the triple meltdowns occurred.
http://www.yomiuri.co.jp/feature/201...OYT1T00402.htm

There are plenty of other news reports regarding radioactive contamination in Japan. I encourage you to do your own research and let us know what news you find.

daveb

Keep in mind the Annual Limit of Intake (ALI) for Cs-137 is 100uCi (3.7 million Bq). This is the amount of radioactivity that would result in 1 year 5000mrem whole body or 50000mrem organ dose (whichever is more restrictive), so (after doing the math) a 1/4 pound hanburger has about 500Bq of Cs-137 (using the 4350 Bq/kg), which is about 700 urem WB or 7mrem organ dose - this is the accumulated dose over a whole year! That's not a lot of additional exposure.

swl

Thanks for letting me know that the food is safe with over 4000Bq/kg of cesium.
Fascinating that the French would spend millions or billions of dollars to process nuclear waste containing only 17Bq/kg, when it's OK to eat waste food containing over 4000Bq per kg. And the cost was not only dollars or francs, there were people injured and killed.

Please share your expert guidance of what level of cesium contamination is acceptable, for the food I'm feeding my toddlers, in Bq/kg. My smallest boy weighs about 13kg.

Thanks again for letting me know my family is safe. My wife and I had been worried.

Borek

I don't remember reading they were processing nuclear waste. Yes, the explosion happened in the waste processing facility, yes, the were processing something - but calling it a waste doesn't automatically follow.

17Bq/kg is less than the level of natural ⁴⁰K radiation in the human body (activity of natural potassium in the 30Bq/g range, amount of potassium in the body in the 0.2% range, so 1 kg contains 2g of potassium, giving something like 60Bq/kg).

My understanding is that what happened in France was just an industrial accident, not different from hundreds of others happening each year.

nikkkom

I'm not an expert, but anyway.

Human body naturally has about 50Bq per kg of activity. Natural variability of background radiation is so that in some places people have higher levels. I would guess activity of 200Bq/kg is not very rare, and ~5000 Bq/kg is the highest naturally occurring level.

Therefore:

Occasionally eating food with 5000 Bq/kg is not something which will kill me. Eating such food often should be avoided, though.

I would consider food with activity 200 Bq/kg or below as "not contaminated".

swl

But wait a minute, you only included the contamination from beef in your calculations. How much room does that leave for other goods such as vegetables, grains, and dairy products that are contaminated?

Or even better, please tell me how many Becquerels you advise is safe to eat on a daily basis?

Drakkith

Hrmmm, why do I sense much sarcasm in your posts?

daveb

I never claimed it was safe. I claimed it was not a lot of additional exposure. The position of the NCRP. ICRP and regulatory agencies is that no additional exposure is 100% safe. However, the regulatory agencies do hold that the additional risk from a certain level of exposure is an acceptable risk.

Please do not accuse of syaing things I did not say.

swl

Please forgive me for misunderstand your assertion 4000Bq/kg is "not a lot of additional exposure" to mean safe. I hope you understand how a simple layman, such as myself, might misunderstand "not a lot" to be safe.

Now that we've established that 4,000Bq/kg (weight of food) is not safe, can I ask a more important question?

How many Bequerels per kg of body weight of Cesium is an "acceptable risk" to eat every day, for the life of a two year old child?

daveb

From a regulatory standpoint, "acceptable risk" allows for a maximum of 100mrem per year whole body to a member of the public from licensed activities. In addition, doses to members of the public must be kept ALARA (As Low As reasonably Achievable). Note that this does not mean as low as possible. Generally (and very general), the NRC has previously said that any cost less than $1000 per person per rem per year is reasonable.

This would equate to 2uCi. This is from internal deposition. Note that this is also the activity that is exempt from licensing, that is, you or I could buy it without a radioactive materials license.

Again, there are some people who hold the opinion that no risk is acceptable.