The impact on food and food production in Japan will depend upon the types of radionuclides and the amount of radioactivity deposited or present where food is being produced or harvested. Although radioactive iodine in food is of immediate concern after nuclear emergencies, it has a relatively short half-life and will naturally decay over a short time frame.
Radioactive caesium has also been detected in food. In contrast to radioactive iodine, radioactive caesium can linger in the environment for many years and could continue to present a longer term problem for food, and food production, and a threat to human health. How do food products become radioactive?
Health effects of Japan's radiation crisis
Foods can become contaminated with radioactive materials when they are released as the result of a nuclear or radiological emergency. In these circumstances, radioactive material falling from the air or carried in rain water or snow, can deposit on the surface of foods like fruits and vegetables or animal feed. Also, over time, radioactivity can build up within food, as radionuclides are transferred through soil into crops or animals.
Radioactivity can also be washed into rivers, lakes and the sea where fish and seafood could take up the radionuclides. The severity of the risk depends on the radionuclide mix and the level of contaminant released. Radioactivity cannot contaminate food that is packaged; for example, tinned or plastic-wrapped food is protected from radioactivity as long as the food is sealed.
Why is food affected in areas beyond the evacuation zone? During a nuclear emergency, an evacuation zone is established to prevent people from being exposed to immediate and unacceptable levels of radiation posing a threat to human health. However, contamination of food can occur through uptake from soil to crops, or to animals through feed, even when levels of radioactive contamination are lower than those which might pose a direct threat to human health. The standards for acceptable limits for radioactivity in food are set at low levels in order to take into account the possibility of contaminated food being eaten over an extended period of time and resulting in a cumulative dose.
Are there rules for radioactivity in foods for international trade? There are internationally agreed Codex Guideline Levels GLs for radionuclide levels in internationally traded food following a nuclear or radiological emergency. When the Guideline Levels are exceeded, national governments shall decide whether and under what circumstances the food should be distributed within their territory or jurisdiction. National governments may wish to adopt different values for internal use within their own territories, where the assumptions concerning food distribution that have been made to derive the Guideline Levels may not apply, e.
In response to the nuclear accident in Japan, Japanese authorities have instituted monitoring of food products and have restricted the consumption and distribution of some products in certain prefectures, or areas found to contain radionuclides exceeding Japan's provisional regulation value. Findings from food monitoring in Japan and decisions related to the consumption and distribution of food products are published regularly on the Ministry of Health, Labour and Welfare web site.
Many countries have implemented food control measures to mirror actions taken within Japan. Other countries have suspended food imports from Japan. In addition, many countries have increased monitoring on foods imported from Japan. Japan Ministry of Health, Labour and Welfare What general advice can be given to food consumers and producers in the event of a nuclear emergency?
How Is Japan's Nuclear Disaster Different?
The response to an emergency involving radioactivity should be the same as the response to any emergency involving any hazardous material contaminating food. In the early stages of an emergency, and if it is safe to do so, it is possible to take immediate actions to prevent or minimize the contamination of food by radiological materials. Many other short-, medium- and long-term actions need to be considered in areas confirmed to be seriously contaminated, such as: avoid consumption of locally produced milk or vegetables; avoid slaughtering animals; avoid consumption and harvesting of aquatic animals and plants including fish, shellfish, and algae ; and avoid hunting or gathering mushrooms or other wild or collected foods.
Current risk Ionizing radiation Human exposure to ionizing radiation Travel advice Health effects Public health actions Personal protective measures during the early phase of a nuclear emergency Food safety Water contamination WHO's response. The Times initially reported that helicopters might be used to drop water on the pools of spent fuel that are too hot.
Later the idea was discounted. In short: follow the water. That's where the alarm bells went off on Monday evening U. EDT following a Japanese press conference in which a top official warned the situation was growing "very grave" and that there were new concerns about the release of radioactive materials that could pose human health risks.
The bulk of the plant's workers were evacuated because of the increased radiation and health risk, with a bare-bones crew of 50 left to continue heroic efforts to contain the ongoing crisis. It is of course the workers who are at greatest risk of short-term radiation sickness and long-term health effects. Beware of single reports of radiation level reports, since radiation levels can frequently fluctuate and it is not clear who is being exposed and for how long.
Public health after a nuclear disaster: beyond radiation risks
The International Atomic Energy Agency IAEA confirmed today that elevated radiation "dose rates up to millisieverts per hour" had been reported at the plant. Falling radiation levels were also reported. The degree of human health risk depends on several factors including: the type of radioactive material involved; the level of radiation in the environment; whether and how long individuals are exposed to the radiation; the cumulative amount or dose of radiation.
Some individuals are more vulnerable than others, particularly pregnant women, young children and seriously ill patients. Reliable measures of levels outside the plant have not been available and won't be for the foreseeable future some journalists and others are wearing radiation dosimeters which will keep track of their individual exposure.
Is enough being done to protect Japanese near Fukushima, and what about those who live farther away? In order to reduce the amount of exposure by residents, the government increased evacuation area around Fukushima to 20 kilometers and asked those living up to 30 kilometers away to stay indoors to further protect them from radiation. During the the Three Mile Island episode there wasn't a mass evacuation, but pregnant women and preschool children were urged to leave the area.
The TMI crisis was relatively short-lived the immediate danger subsided after three days and involved just one reactor.
How dangerous is the radiation from the damaged Japanese nuclear reactors?
The Japan crisis is far larger and will clearly last far longer. This is highly pertinent.
The wind direction, should there be a plume containing radioactive material, determines whether fallout will land on populated areas or in the sea. One bright spot here -- dare I say "new hope," at least temporarily? Because low-levels of airborne radiation dissipate over time and distance, officials have said they don't expect this to pose a significant health risk in Hawaii or the mainland U.
Should we believe the official sources of information? Frustration continues to grow in about the confusing, often contradictory, information emanating from the Japanese government and the company running Fukushima not to mention dueling experts in some of international media.
Concerns have inevitably surfaced that some of the key players may be downplaying the situation as was charged during TMI and some finger-pointing about the company's handling has begun. But the situation is still so serious that it seems unlikely it's being downplayed at the moment by those in power. How is the global media handling all of this? Coverage by American news outlets has steadily improved, with more in-depth, informative updates replacing the limited, confusing weekend reports.
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