I've been reading a lot about nuclear power plants in general and nuclear disasters in particular, namely, Chernobyl, Three-Mile Island, and UK's Windscale disasters, and will soon read about the one in Russia in 1957.
I alternate the news and other information sites, but always include both the Japanese media, American or other news outlet:
- NHK (Japanese broadcaster)
- Japan Today
- Yahoo (AP)
- CNN
- Reuters
- NPR
- BBC
- NY Times
I have started reading scientific journals and information from health organizations, like the World Health Organization, like these: Science/health Organizations/Publications:
- MIT Nuclear Science and Engineering (NSE) Nuclear Information Hub
- Scientific American
- U.S. Nuclear Regulatory Commission (NRC)'s website
- World Health Organization (WHO)'s website
- US Embassy in Japan's website
- UK Embassy in Japan's website
So...I don't think I'm really kept in the dark by the Japanese media/government, which, as many people believe, is likely trying to downplay the gravity of the situation and to avoid conveying just how much (or how little, as the case may be) control they have over the situation.
Still, I think that American media outlets have blown things way out of proportion. One indication was its reporting on the "panic" that residents of Tokyo felt, "evidenced" by the shortages of food and other necessities at local supermarkets.
Sure, around last Sunday/Monday, convenience stores and supermarkets sold out of convenience foods (ready-to-eat foods like bread, easily cooked foods such as eggs and instant noodles and soups, and essentials like rice).
But there was still plenty of produce, potatoes, meat, fish, etc at the two big supermarkets near me (Queen's Isetan and Peacock). So...is that really a food shortage?
I think that people were buying up convenience foods because of the rolling blackouts and they weren't sure if it would affect them. So, given a choice between being able to have food ready in 5 minutes or 50, it made sense which to choose.
Following the American media's inaccurate portrayal of the food situation, I feel somewhat skeptical about their grasp of the situation here regarding worst-case scenarios for the nuclear plant.
Many of the fears now in and about Japan have to do with the radiation that is coming out of the nuclear reactors in Fukushima being released into the air. However, we are exposed to radiation on a daily basis.
I am not saying that because of this daily exposure, what is happening up north is no big deal and that we can safely ignore it. I am also not saying that the continued and pervasive use of radioactive material is necessarily positive or healthy.
But I do think that before we all start freaking out (oops, too late, it seems, in the case of the US, Italy, China, etc), I think it's important to understand the baseline or normal levels of radiation before we can fully understand the effects that Fukushima would have.
According to the U.S. Nuclear Regulatory Commission, we are exposed to radiation on a daily basis as such:
Cosmic Radiation
The sun and stars send a constant stream of
cosmic radiation to Earth, much like a steady drizzle of rain. Differences in elevation, atmospheric conditions, and the Earth's magnetic field can change the amount (or
dose) of cosmic radiation that we receive.
Terrestrial Radiation
The Earth itself is a source of
terrestrial radiation. Radioactive materials (including
uranium, thorium, and
radium) exist naturally in soil and rock. Essentially all air contains
radon, which is responsible for most of the dose that Americans receive each year from natural background sources. In addition, water contains small amounts of dissolved uranium and thorium, and all organic matter (both plant and animal) contains radioactive carbon and potassium. Some of these materials are ingested with food and water, while others (such as radon) are inhaled. The
dose from terrestrial sources varies in different parts of the world, but locations with higher soil concentrations of uranium and thorium generally have higher doses.
Internal Radiation
All people have internal radiation, mainly from radioactive potassium-40 and carbon-14 inside their bodies from birth and, therefore, are sources of exposure to others. The variation in
dose from one person to another is not as great as that associated with cosmic and terrestrial sources.
Man-Made Sources
Although all living things are exposed to natural background radiation, exposure to man-made radiation sources differs for the following groups:
In general, the following man-made sources expose the public to radiation (the significant radioactive isotopes are indicated in parentheses):
- Medical Sources (by far, the most significant man-made source)
- Nuclear medicine procedures (iodine-131, cesium-137, and others)
- Consumer Products
- Building and road construction materials
- Combustible fuels, including gas and coal
- X-ray security systems
- Televisions
- Fluorescent lamp starters
- Smoke detectors (americium)
- Luminous watches (tritium)
- Lantern mantles (thorium)
- Tobacco (polonium-210)
- Ophthalmic glass used in eyeglasses
- Some ceramics
To a lesser degree, the public is also exposed to radiation from the nuclear fuel cycle, from uranium mining and milling to disposal of used (spent) fuel. In addition, the public receives some minimal exposure from the transportation of radioactive materials and fallout from nuclear weapons testing and reactor accidents (such as Chernobyl). For that reason, the U.S. Nuclear Regulatory Commission (NRC) requires its licensees to limit the maximum radiation exposure to individual members of the public to 100 mrem (1 mSv) per year. The related NRC regulations and radiation exposure limits are contained in Title 10, Part 20, of the
Code of Federal Regulations (
10 CFR Part 20).
Occupationally Exposed Individuals
In general, occupationally exposed individuals work in the following areas:
Such individuals are exposed to varying amounts of radiation, depending on their specific jobs and the sources with which they work (including cobalt-60, cesium-137, americium-241, and other isotopes). For that reason, the NRC requires its licensees to limit occupational exposure to adults working with radioactive material to 5,000 mrem (50 mSv) per year. The related NRC regulations and radiation exposure limits are contained in
10 CFR Part 20. Toward that end, employers carefully monitor the exposure of these individuals using instruments called
dosimeters.
Now the fear has grown to include radiation in food up to 90 miles away (according to the NYT) and tap water up to 150 miles away in Tokyo, both areas well outside Japan's established 20-km (12.4-mile) and the US's recommended 50-mile radius safe zone.
The NYT article:
Dr. Harold M. Swartz, a professor of medicine at Dartmouth who studies radiation exposure in people, said that the contamination levels were low and that the government’s advice was “probably reasonable.” But, he added, because people are so afraid of radiation, they are likely to avoid these foods altogether.
Another expert, David J. Brenner, director of the Center for Radiological Research at
Columbia University, said it “seems unnecessary to eat these” foods.
“I wouldn’t,” Dr. Brenner said.
NPR today
reported:
"...a couple of pounds of spinach grown in the open air near the city of Hitachi, about 60 miles south of the Fukushima power plant, was found to contain 54,000 becquerels of iodine-131. The allowable government limit is 2,000 — or 27 times lower.
The cesium-137 level in Hitachi spinach was about 2,000 becquerels, four times the safety threshold.
Milk from the region has also tested positive for radioactive iodine, though the levels are unclear. Milk from 37 farms in Fukushima prefecture is being withheld from the market....
Experts and post-mortem review of the Chernobyl disaster conclude that almost all its public health effects were due to the ingestion of contaminated milk and leafy vegetables for weeks after the facility spewed radioactive particles into the atmosphere....
The main result, largely attributed to tainted milk, has been an epidemic of more than 6,000 thyroid cancers, nearly all among people who were children or adolescents at the time of the Chernobyl catastrophe. Of these, 15 had proved fatal by 2005.
But I wonder what general rate of thyroid cancer is among the subjects' cohorts. Yes, there were more than 6,000 cases, but how many people were children or adolescents were there in total in the areas affected by Chernobyl?
[3/27/11 Edit: See
On Media Portrayal of Nuclear "Safety" for more details, but there were 600,000 clean-up workers, including 300,000 exposed to relatively high levels of radiation; an additional 600 workers on-site the day of the explosion; and an unknown number of people who were children at the time. However, both the World Health Organization (WHO) and the International Atomic Energy Agency (IAEA) have stated that the numbers of children with cancer were above normal.]
From what I understand, eating leafy vegetables contributed to these cancers because such vegetables are larger surface areas on which the radioactive particles fell. And the milk became carcinogenic because the particles fell on the grass, the cows ate the grass growing in the now-contaminated soil, and produced tainted milk.
This is something I want to read more about.
According to nuclear scientists interviewed by NPR and the BBC, the danger posed by radioactive iodine is not in its airborne form, since something like 80-95% of it is washed away when you take a shower and wash your hair after exposure. (The amount and duration of exposure has to be factored in, of course.) They said that the read danger is when radioactive matter enters into the food and water supply.
Some questions
I wonder if the effects can be limited by washing vegetables before eating and by avoiding dairy products from the region for awhile.
According to CNN:
Radioactive iodine (iodine-131) has a half-life of eight days, cesium-137's half-life is about 30 years.
Seawater radiation monitoring detected levels of iodine-131 that were 126.7 times higher than government-set standards, the electric company said on its website. Its monitors detected caesium-134, which has a half-life of about two years, about 24.8 times higher than the government standards. Cesium-137 was found to be 16.5 times higher than the standard.
Fukushima, northeast of Tokyo, has Japan's fourth-largest amount of farmland and ranks among its top producer of fruits, vegetables and rice. Ibaraki, south of Fukushima, supplies Tokyo with a significant amount of fruits and vegetables and is Japan's third-largest pork producer.
For radiation to be an issue for rice, the contamination would have to be more severe and prolonged [than] what has been seen so far, said McBride, the Cornell University professor [who studies crop and soil science].
Amidst more severe levels of radiation, radioactive particles that fall from the air could contaminate the soil, and the plant could take them in. Soil contamination was a huge issue around Chernobyl, but the radiation issue at Fukushima Daiichi isn't anywhere near that situation, he said.
"We're not at that stage; that's the scenario you have to consider if contamination gets severe enough," McBride said.
Hygiene expert Satoshi Takaya, who helped Japanese scientists prevent contaminated food from entering the country at that time, said the current situation is no Chernobyl -- but he said the current crisis is sure to affect Japanese farmers.
Short-term exposure to food contaminated by radiation from Japan's damaged Fukushima Daiichi nuclear plant poses no immediate health risk, a spokesman for the World Health Organization said Monday.
While the verdict is not yet out on
food irradiation and there are negative consequences for the food itself (lowered nutritional value) and possible health risks, "
In 1963, the Food and Drug Administration (FDA) found the irradiation of food to be safe. Irradiation of meat and poultry is done in a government-approved irradiation facility." This is done because to reduce "harmful bacteria that may be present in food, including E. coliO157:H7, Salmonella, and Campylobacter."
This is from a pro-irradiating website:
| Until recently only bulk dried spices were irradiated in the United States. Since January 1992 irradiated produce has been sold in some U.S. supermarkets. Starting in 1995, several thousand pounds of tropical fruits annually were irradiated and sold in Midwest and California markets. In July of 2000 a new facility in Hawaii permitted the transport of high quality tropical fruits previously banned for insect quarantine purposes. |
In May of 2000, irradiated frozen ground beef was first sold in Minneapolis and quick spread to adjacent states. In early 2001 over 20,000 supermarkets in more than 16 states offer irradiated patties by Huiskens. Colorado beef offers frozen patties from supermarkets. In the mail order arena, several providers including Omaha steaks and Schwan's offer irradiated ground beef. Frozen irradiated chicken breasts have been available in the Florida area since the late 1990's."
UK has been irradiating food too limited to spices now because of public uproar, though it allows for the import of irradiated food includes vegetables, fruit, cereal, tubers, fish and shellfish, and poultry.
Irradiated food in the US is supposed to have a certain logo on it, but I have never seen this logo anywhere (much like there is no labeling regarding genetically-modified corn or other products).
Still, this means that unless the food you've been eating since 1963 has come directly from a farmer or rancher or from an organic source, chances are, you've been ingesting irradiated food for quite some time.
Oh, and the UK uses
"gamma rays from the radionuclide caesium-137" as one of the ways to irradiate food."
(Hm...maybe that's why the UK still hasn't asked its citizen to leave Japan. They have been subjecting their citizens to Cs-137 for awhile now.)
From my readings of "Silent Spring" and other materials, I know that some toxins are water-soluble, so once you urinate, the toxins come out into the toilet. Other toxins, like mercury, are fat-soluble, so they can't be gotten rid of (unless you have 0% body fat, in which case, you'd die anyway). The mercury climbs the food chain ladder from smaller to bigger fish, and stays indefinitely in the bodies of whatever or whoever eats the mercury-containing fish, for example.
I'm not sure yet how radiation travels in the food system. If it gets into the soil, how does it affect the things growing in that soil? Are the root vegetables (like carrots, potatoes, etc) grown in that soil immediately harmful, or only harmful in the long run after accumulating radioactive particles through the soil over a period of time? If we avoid all food grown in a huge radius from Fukushima, what effects, if any, would radiation then have on the food supply in Tokyo?
What about the water supply?
[3/27/11 Edit: The day after the Japanese government announced that the radiation levels in the tap water were above those safe for infants, but within the limits safe for adults, it said that the levels were back to normal again. We are still using bottled carbonated water, just in case. Carbonated, because regular bottled water has been selling out like crazy.]
I had read a few days ago (before the discovery of radiation in the food and tap water) that the amount of radiation being emitted from the plants would blow out into sea, and that the particles would be so dispersed that it wouldn't have any effect on the fish and other sea animals that we'd eat there. What now?
[3/27/11 Edit: The government, and the IAEA as well, I believe, has said that it would start measuring radiation in the ocean at the shore, 10m from the shore, 20m, etc. We are avoiding fish from near Fukushima. But Japan is made up of many islands, so there are literally, many other fish in the sea. Besides, Japan also imports a lot of fish and seafood.]
The Iodine-131 and cesium-137 found in the food and water and being talked about in all media outlets are not the only radioactive by-products of a nuclear fission reaction. This is from the website of
MIT's Nuclear Science and Engineering Department:
| Yield | Fission Product | Half-life |
| 6.8% | cesium-134 | 2 years |
| 6.3% | iodine-135 / xenon-135 | 7 hours |
| 6.3% | zirconium-93 | 1.5 million years |
| 6.1% | cesium-137 | 30 years |
| 6.1% | molybdenum-99 / technetium-99 | 200,000 years |
| 5.8% | strontium-90 | 30 years |
| 2.8% | iodine-131 | 8 days |
| 2.3% | promethium-147 | 3 years |
| 1.1% | samarium-149 | not radioactive |
| 0.7% | iodine-129 | 15 million years |
| 0.4% | samarium-151 | 90 years |
| 0.4% | ruthenium-106 | 1 year |
| 0.3% | krypton-85 | 11 years |
| 0.2% | palladium-107 | 7 million years |
Note that longer half-lives do not necessarily mean more danger. Some fission products have extremely long half-lives but emit very little radiation at any given time, so they are not dangerous. Other fission products emit huge amounts of radiation but exist for such a short period of time that they are not dangerous. How harmful a given fission product is to humans is a complicated function of half-life, radiation intensity, and various human biology factors.
Of course, MIT NSE is very pro-nuclear, but again, we have to understand the science. Now the questions are...how harmful are these? Are only Iodine-131 and cesium-137 talked about because they are more dispersed (due to the weight of the particles) or because it's difficult to report on 14 different radioactive materials?
[3/27/11 Edit: From what I've read, it IS because the other particles are heavier that they don't disperse as much.]
The Center for Disease Control (CDC) mentions the use of Prussian Blue on its website as a means to decrease the half-life of radioactive cesium ("mainly Cs-137") by half and allow it to be passed through the bowels. But it also describes the half-life of cesium as roughly 110 days, which is markedly different from the 30 years described by MIT and the media.
So which is it? And how come the media has described potassium iodine and various governments have handed out the pills but no one's mentioned Prussian Blue? Is it because iodine-131 exists in greater quantities and is more dangerous?
[3/27/11 Edit: Cs-137 does have a half-life of 30 years, but because it's water soluble, its actual half-life in a person (or animal, etc), is only 110 days. I suppose Cs-137 is less dangerous since basically, you can "pee it out" of your system. But with iodine-131, it stays in the food chain, like I might have mentioned previously. So the radiation in the tiny fish that eats it will end up in the medium fish that eats that, and so on. The US government announced a few days ago that it's making potassium iodine pills available to American citizens here who want it, but is recommending that people NOT take it just yet, since the side effects are worse than the radiation risk *right now.* The US or Japanese government or IAEA will tell the public when "go time" is.]
