A total of 0.1 percent of major food products from the 17 prefectures northeast of Shizuoka Prefecture registered radioactive contamination released in the Fukushima nuclear crisis in fiscal 2015, according to the Ministry of Agriculture, Forestry and Fisheries.
The government has been measuring radioactive contamination levels in the farm and marine products regularly since the meltdown at the Fukushima No. 1 nuclear plant. Immediately after the outbreak of the nuclear disaster in March 2011, radioactive cesium was detected in domesticated rice and beef. However, as the government has taken measures to reduce radiation levels in food items, cesium exceeding the government-set limit is now detected only in wild vegetables, game meat and the like, raising questions over whether to continue the intense inspection regime.
The upper limit for radioactive cesium in food items is 100 becquerels per kilogram. This level was set in April 20112 to satisfy the safety concerns of the public, but is in fact more than 10 times stricter than the European Union standard.
According to the agriculture ministry, 260,538 food items were inspected in fiscal 2015, and 99 percent of farm products had cesium of less than 25 becquerels per kilogram. The tests showed that 264 items, or 0.1 percent of the total, had cesium exceeding the upper limit. Of these, 259 -- or 98 percent -- were wild mushrooms, game meat, freshwater fish and other so-called "hard-to-control items."
The remaining five cases were farmed produce: two cases of rice (in Fukushima Prefecture); two cases of soybeans (in Fukushima Prefecture); and one case of buckwheat (in Iwate Prefecture). The rice happened to be cultivated for private use. The government has been checking all bags of rice grown in Fukushima Prefecture as part of efforts to respond to consumer concerns. Therefore, there have been no cases of rice exceeding the upper cesium limit being shipped.
The agriculture ministry says it is known that plenty of potassium fertilizer can help curb cesium absorption. It was found that the soybeans and buckwheat exceeded the upper limit because they were grown in places that had insufficient potassium fertilizer. None of those products was shipped to market. Besides these fresh foods, 15 processed food items such as dried persimmons had cesium exceeding the upper limit.
Meanwhile, consumers have great concern over ocean fish caught near Fukushima Prefecture partly because of the contaminated water leaking from the crippled Fukushima nuclear power station. The local fishery has voluntarily abstained from operating along the Fukushima Prefecture coast, but fish such as flounder and Pacific cod have been caught in waters off the coast.
Shortly after the outbreak of the nuclear crisis, 6 to 16 percent of the fish caught off the coast exceeded the upper limit, but none of the fish caught in the same area exceeded the limit last year. However, river fish such as mountain trout and Japanese daces continue to register cesium exceeding the upper limit, as radioactive materials in un-decontaminated mountain forests flow into the rivers when it rains. Up to 240 becquerels of cesium was detected last year in freshwater fish in five prefectures including Fukushima, Tochigi and Miyagi.
In the wake of the nuclear accident, there was a spate of cases in which beef cattle which ate rice straw contaminated with cesium had cesium exceeding the safety limit. As such, all beef cattle and beef have been inspected for cesium in the 17 prefectures for the past five years. However, no beef cattle have registered cesium over the legal limit in the past three.
Strontium-90, which is believed to be easily absorbed into bones and cause cancer, was detected in two items. But the density of the radioactive isotope in those items was 0.35 becquerels per kilogram and 0.05 becquerels per kilogram -- about the same as before the nuclear crisis.
The cumulative cost of inspections in the 17 prefectures is about 4 billion yen. An official of the agriculture ministry's Food Safety Policy Division told the Mainichi Shimbun, "The cesium levels of 99.99 percent of vegetables, tubers and roots have dropped below 25 becquerels. There must be farm products for which we can scale down inspections if cultivation management continues to be carried out properly as in the past."
The Consumer Affairs Agency and other organizations hosted a symposium in Tokyo earlier this month on ways of handling radioactive materials in food products and conducting inspections, and to discuss a future inspection system. While a consumer group called on the government to continue the inspection system as the results would help the public feel secure, some stated that the risk of cesium contamination was extremely low and that it would be better to use the funds for fighting disease-causing germs that pose a higher risk.
Unfavorable reputations hurting specific production areas were also reported at the symposium. Osamu Kimijima, a 65-year-old shiitake mushroom farmer from Yaita, Tochigi Prefecture, who joined the symposium as a panelist, said, "We are still suffering from groundless rumors." He cultivated shiitake mushrooms on about 100,000 logs before the nuclear meltdowns, but he abandoned all of them after the nuclear incident and bought new logs from Kyushu.
Kimijima currently uses about 50,000 logs and ships about 7 to 8 metric tons of shiitake mushrooms each year. Only about 5 becquerels of cesium are detected in his shiitake, but the problem is that gate prices are low. Kimijima called for understanding from consumers to dispel groundless rumors.
"The prices are about half of those from other production areas simply because they are produced in Tochigi Prefecture. We are trying to sell them on a negotiation basis at direct sales depots and the like as much as possible," he said.
Takeshi Yamasaki, head of the non-profit organization Science of Food Safety and Security and symposium attendee, said, "No matter how you look at it, it is excessive to inspect all cattle. Even if the scope of inspections is scaled down, there will be no change in risks involving beef." He emphasized that it will be enough to conduct monitoring specific to individual situations.
Apart from individual food products, what are radiation exposure levels of entire everyday meals? The Health, Labor and Welfare Ministry purchased 210 items such as rice, vegetables and fish at supermarkets in 13 prefectures including Tokyo, Fukushima and Iwate between September and October of 2015, and calculated the annual dosage of cesium individuals receive from each food product.
The results of the ministry's calculations were 0.0009 to 0.0015 millisieverts. Food products in other prefectures had 0.0006 to 0.0012 millisieverts. After all, there was little difference between them. The cesium dosages are about one-thousandth of the annual exposure of 1 millisievert -- the baseline for safety limits for food products. A health ministry official said, "The risk stemming from receiving cesium from meals as a whole is extremely small."