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]

The government falsely claims to have control of radiation levels of goods.

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.

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.

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.

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.

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]

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.

Government? Lying? Can't be! :D

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.

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?

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.

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.

Also it is exceedingly unlikely that any contamination would result in large increases in exposure compared to the background level.

You base this conclusion on what exactly?

 

[Drakkith]

Government? Lying? Can't be! :D

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

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?

Only in severe contamination.

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.

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.

You base this conclusion on what exactly?

Probability.

 

[nikkkom]

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

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?

Only in severe contamination.

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]

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.

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.htmlIbaragi 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/akita/news/20110907-OYT8T01135.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/nougi/hiryouhp/fuyoudo3.htmContaminated 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/20110316-866921/news/20110719-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]

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
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/20110316-866921/news/20110719-OYT1T00402.htm

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]

That's not a lot of additional exposure.

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 [STRIKE]waste[/STRIKE] food containing over 4000Bq per kg. And the cost was not only dollars or francs, there were people injured and killed.

http://www.europe1.fr/France/Explosion-radioactivite-tres-faible-au-sein-du-four-714153/ The content of the furnace that exploded was 4 tons of material with a 67,000 Bq total, or 17 Bq / kg.

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]

Fascinating that the French would spend millions or billions of dollars to process nuclear waste containing only 17Bq/kg

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]

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.

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]

That's not a lot of additional exposure.

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]

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

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]

I never claimed it was safe. I claimed it was not a lot of additional exposure. 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.

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.

 

[tsutsuji]

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.

SOCODEI processes "type FMA-VC and TFA" radioactive waste or short-lived* middle-low-activity materials and very-low-activity materials.

* Materials with a radioactive half-life not exceeding 30 years.
http://www.socodei.fr/en/waste-processing/

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.

All Becquerels are not equal. [STRIKE]The short-lived radioactive substances produce more harmful Becquerels than the long life ones.[/STRIKE] (*) The harm depends also on the exposure mode of the human body, whether through external exposure or through inhalation or ingestion. As the news report does not tell which substances were present in the furnace, it is not possible to elaborate much further. If the average radiation in the furnace is 17 Bq/kg, it could result of the mixing of 0.1% with 17,000 Bq/kg(*) with 99,9% with 0 Bq/kg. I guess in some cases only the surface of the materials processed is contaminated, while the inside is clean. Bq/kg is probably not a very useful unit when dealing with surface phenomenons.

(*) Socodei's upper limit for waste acceptance seems to be 0.37 GBq/kg (370,000,000 Bq/kg) (the legal upper limit for "FMA-VC" mentioned at http://www.laradioactivite.com/fr/site/pages/DechetsFMAVC.htm ) (the legal upper limit for TFA is 100,000 Bq/kg: http://www.laradioactivite.com/fr/site/pages/DechetsTFA.htm )

Two containment barriers separate radioactive material from the environment.

Building design provisions ensure that even in the event of a malfunction, exposure would never exceed 1 millliSievert (the annual exposure limit for people living within the vicinity of nuclear facilities).
http://www.socodei.fr/en/qse-management/centraco-a-clean-plant/

(*) edit: that part was wrong, as remarked below.

 

[Astronuc]

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.

I believe the "maximum of 100mrem per year whole body to a member of the public from licensed activities" applies to adults or folks 18 yrs and older. We had a cumulative dose number that started at 18. For those below 18, the cumulative dose was essentially zero.

Pregnant women (actually, the fetus), infants and children are much more sensitive to effects of radiation because of the higher rate of mitosis.

I'll try to find some better answers to swl's questions.

 

[Borek]

All Becquerels are not equal. The short-lived radioactive substances produce more harmful Becquerels than the long life ones.

While I agree Bq are not equivalent, as it depends on radiation type and energy, I don't see how it is related to the half life.

 

[daveb]

I believe the "maximum of 100mrem per year whole body to a member of the public from licensed activities" applies to adults or folks 18 yrs and older. We had a cumulative dose number that started at 18. For those below 18, the cumulative dose was essentially zero.

Pregnant women (actually, the fetus), infants and children are much more sensitive to effects of radiation because of the higher rate of mitosis.

I'll try to find some better answers to swl's questions.

The regulatory limits for WB are:

5000mrem/year to occupational workers over the age of 18
500mrem/year to occupational workers under the age of 18
500mrem to the fetus of a declared pregnant worker over the course of the pregnancy
100mrem/year to members of the public (regardless of age)

Plus the constraint rule on effluent emissions to the nearest probable member of the public of 10mrem/year.

Yours may have been an internal requirement, though I can't see how you could legitimately prove that your increased exposures to members of the public under age 18 were essentially zero.

 

[tsutsuji]

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?

The Japanese government's answer to the question in terms of weight of food　for infants (less than 1 year old) is

*）Provide guidance so that materials exceeding 100 Bq/kg are not used in milk supplied for use in powdered baby formula or for direct drinking to baby.
http://www.mhlw.go.jp/stf/houdou/2r9852000001558e-img/2r98520000015av4.pdf

This regulation is based on the "Manual for Measuring Radioactivity of Foods in Case of Emergency" dated May 9, 2002, which includes statistics about the food eaten by average Japanese people : 600 grams of milk per day for infants (table on http://www.mhlw.go.jp/stf/houdou/2r9852000001558e-img/2r98520000015cfn.pdf p.37 (pdf page number 38))

For a 2 year old child, the Japanese government limit is the same as that for adults.　The table on http://www.mhlw.go.jp/stf/houdou/2r9852000001558e-img/2r98520000015cfn.pdf p.37 (pdf page number 38) includes statistics for "幼児" (preschool children above 1 year old) : 178 g/day of milk and dairy products, 152 g/day of cereals, etc. Which shows they were taken into account when deciding the regulation.

 

[daveb]

While I agree Bq are not equivalent, as it depends on radiation type and energy, I don't see how it is related to the half life.

True. I'll take 37MBq of Tc-99m (140keV photon, 6.0 hr half-life, which is a typical nuclear medicine diagnotic dose) over the same activity of cobalt-60 (1.33 and 1.17 MeV photons, 5.26 year half-life).

 

[tsutsuji]

While I agree Bq are not equivalent, as it depends on radiation type and energy, I don't see how it is related to the half life.

Oops sorry. That was just plainly wrong. I withdraw that statement.

 

[Caniche]

Would it be fair to say that you could reduce your exposure to Fukushima fallout by avoiding consumption of anything caught or trawled from the north Pacific?

 

[daveb]

Would it be fair to say that you could reduce your exposure to Fukushima fallout by avoiding consumption of anything caught or trawled from the north Pacific?

Technically, that's possible, but I would imagine it isn't noticeable, especially now, since any contamination has had a chance to become diluted throughout the oceans. Remember, the solution to pollution is dilution!

 

[daveb]

I found some information from the http://www-pub.iaea.org/MTCD/publications/PDF/Pub996_EN.pdf" on page 181 that lists the doses from ingestion of various radionuclides. For Cs-137:

Age Dose (Sv/Bq)
1-2 1.2E-8
2-7 9.6E-9
7-12 1.0E-8
12-17 1.3E-8
17+ 1.3E-8

 

[swl]

Radioactive Used Car: 20.38 Microsieverts/Hr Car from Japan Destined for Kenya

Apparently the government is now allowing evacuees to go into the exclusion zone to get their contaminated cars. For some reason, some of them no longer want to drive these cars.
According to the government "That level of radiation does not have an immediate effect on the human body."

What a meaningless statement the government and nuclear industry keep repeating.
Even 5 Sieverts/hr has no immediate effect on the body.
Illness and death by radiation of any level are rarely immediate.

In this case the car shipment was stopped at the port in Kawasaki.
http://ex-skf.blogspot.com/2011/10/radioactive-used-car-2038.html

 

[Shinjukusam]

Radioactive Used Car: 20.38 Microsieverts/Hr Car from Japan Destined for Kenya

Apparently the government is now allowing evacuees to go into the exclusion zone to get their contaminated cars. For some reason, some of them no longer want to drive these cars.*
According to the government*"That level of radiation does not have an immediate effect on human body."

What a meaningless statement the government and nuclear industry keep repeating.*
It should be noted that 5 Sievert/hr has no immediate effect on the body.*
Illness and death by radiation of any level is rarely immediate.*
In this case the car shipment was stopped at the port in Kawasaki.*
http://ex-skf.blogspot.com/2011/10/radioactive-used-car-2038.html

Is there some special meaning for the * marks?

 

[swl]

Is there some special meaning for the * marks?

Sorry, no special meaning. Seems to be some sort of problem when I post from my iPhone.

 

[Shinjukusam]

Ah, gotcha. Thought you were trying to send links that weren't going through.

 

[daveb]

Radioactive Used Car: 20.38 Microsieverts/Hr Car from Japan Destined for Kenya

Apparently the government is now allowing evacuees to go into the exclusion zone to get their contaminated cars. For some reason, some of them no longer want to drive these cars.
According to the government "That level of radiation does not have an immediate effect on the human body."

What a meaningless statement the government and nuclear industry keep repeating.
Even 5 Sieverts/hr has no immediate effect on the body.
Illness and death by radiation of any level are rarely immediate.

In this case the car shipment was stopped at the port in Kawasaki.
http://ex-skf.blogspot.com/2011/10/radioactive-used-car-2038.html

I have to assume the translation from Japanese is accurate, but i doubt the credibility of the source itself since it's a blog and not any agency. 20 uSv/hr exceeds any IAEA, ICRP or NCRP recommendation (as well as NRC requirement) for unrestricted areas. As for "the government and nuclear industry" saying it has no immediate effect, no one with any sense of radiation science will make such an erroneous statement. The blog post mentioned Kawasaki City, so I doubt it was by anyone with any type of authority (and if it was, they have no idea what they're talking about - while it's true it has no "immediate effect" that's detectable, it can have long term stochastic effects).

 

[QuantumPion]

while it's true it has no "immediate effect" that's detectable, it can have long term stochastic effects).

Is there any scientific basis for this statement? I was unaware of any statistical analysis showing this to be the case. As far as I am aware, it is only assumed to be true for the purposes of worst-case scenario in risk analysis.

 

[QuantumPion]

Good article here: http://www.nature.com/news/2011/110405/full/news.2011.206.html

 

[daveb]

Low dose studies are very difficult to analyze, which is why I used the word "can", meaning, "possibly" in this case (not "can" as "will in some and won't in another" - the difficulty with multiple definitions).