As the situation at the Fukushima nuclear plants has begun to stabilize, a new threat to the economic recovery of Japan and the livelihood of Japanese farmers and exporters has begun to rear its ugly head. Reports are now surfacing of food testing positive for radioisotopes traced to the core venting at Fukushima.
Japan’s radioactive food found in major local producer
The disclosure Saturday by Japanese authorities that milk and spinach have shown higher-than-normal levels of radiation contamination has raised concerns about food safety and supplies in one of Japan’s most heavily populated regions.
Tainted milk was found 30 kilometers (18 1/2 miles) from the Fukushima Daiichi nuclear plant and spinach was collected as far as 100 kilometers (65 miles) to the south, almost halfway to Tokyo. The plant was badly damaged after a 9.0 earthquake and subsequent tsunami hit the coast on March 11.
But Chief Cabinet Secretary Yukio Edano stressed to reporters Saturday afternoon that the levels were not extremely high: A person who consumed these products continuously for a year, he said, would take in the same amount of radiation as that of a single CT scan.
The U.S. Food and Drug Administration said that equates to 7 millisieverts, more than double the 3 millisieverts that a person in an industrialized country is typically exposed to in a year.
Health effects would become more evident, he said, if such products were taken in daily for a lifetime. Edano said high radiation levels were not systemic for all spinach and milk tested, and that more data would be collected and analyzed under the Japanese health ministry’s watch to help determine what steps to take next.
The Fukushima prefecture, or province, is just to the northeast of Tokyo. According to the prefecture’s website, Fukushima plays an important role in supplying food, not only to Tokyo, but also to the nation. The prefecture is Japan’s fourth-largest farmland area and ranks among the top producer of fruits, vegetables, rice, tobacco and raw silk. The favorable climate lends itself to an active agricultural industry that includes livestock farming.
The website also states that the prefecture’s 159 kilometer-long coastline is home to a thriving fishing and seafood processing industry, and the area’s haul of fish is among Japan’s largest.
Neighboring Ibaraki prefecture supplies Tokyo with a significant amount of fruits and vegetables. Ibaraki is the largest producer of Andes melons in Japan, according to the prefecture’s website, as well as the country’s third-largest producer of pork.
Most information available is fairly vague about both the type of radioisotope found in foods and the total amount. That said, current measurements may not be entirely reliable, since levels tend to vary quite widely and a small number of samples may not provide a reliable reflection of the actual levels in the overall food supply.
Based on official statements that eating such foods for a year would result in the same level of radiation exposure as a single CT scan, it appears that the levels of radioactivity are extremely low. While this would indeed result in a greater dose than most people get in a year, this is only if you ate exclusively the spinach and milk every day for breakfast, lunch and dinner for 365 days. Of course this would never happen in the real world, where a person might drink a glass or two of milk a day (not all of which generally comes from one source) and, at most, may have a couple of servings of spinach per week. In that circumstance, the worst reasonable dose anyone could be expected to receive is extremely low.
Further press reports have indicated that the radioisotope which has been detected in many of the foods is iodine-131. This isotope is considered dangerous because of the potential to cause thyroid cancer, although it seems levels detected thus far are very low and thus such concerns are not warranted.
Cabinet secretary Yukio Edano said spinach and milk were the only products from nearby farms found with abnormally high radiation levels. But many farms have not yet been tested amid the overwhelming crisis.
Inspectors said milk had five times the safe level of iodine-131 and spinach was more than seven times higher.
This is in fact very good news when it comes to the long term safety of Japanese food supplies. It is known that low levels of iodine-131 were present in the steam vented from the Fukushima nuclear plant. Iodine can exist as a gas and tends to be fairly mobile in the enviornment. The fact that this is the only isotope mentioned means that the incident at Fukushima does not appear to have released significant quantities of less volatile but more persistent isotopes.
Because iodine-131 has a very short half-life, it is not normally found in the enviornment in any measurable concentration. The iodine-131 produced by nuclear tests in the 1950′s has long decayed away. Therefore, even the tiniest concentration of iodine-131 will stand out when tested for, and modern testing methods, such as liquid scintillation spectroscopy are extremely sensitive to even the tiniest traces of such isotopes.
Although the current concentrations may, in some cases, exceed the extremely conservative standards for iodine-131 in foods, this does not mean that the foods are dangerous at all. However, even if the levels are high enough to preclude their sale, they also do not need to be thrown away. Since iodine-131 has a half-life of about eight days, foods found to be containing it can simply be diverted to use in processed food products, such as canned spinach, ice cream, evaporated milk, frozen dinners and so on. Such products typically are kept in storage for some time before making it to consumers anyway, and canned foods may be stored for months. This provides ample time for all the iodine-131 to decay away. Furthermore, the short half-life of iodine-131 means that the levels present in Japanese foods will be down to approximately zero within a few weeks.
The greater concern is not the health effects but the panic and bad press that this has generated. Some countries are already stating that they will be inspecting Japanese food imports for radioactivity. Considering the toll that the earthquake and tsunami has taken on the Japanese economy, the country can’t afford to see another crisis develop over irrational fears. The livelihood of Japanese farmers and exporters may depend on a rational response to this non-issue.
This entry was posted on Sunday, March 20th, 2011 at 10:09 am and is filed under Agriculture, Bad Science, Enviornment, media, Nuclear, Politics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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