On January 6 the Asahi Shimbun reported on wild mushrooms in Aomori Prefecture, 350 kilometers north of Fukushima Daiichi, have radioactive Cesium levels above the 100 Becquerels per kilogram national standard which could not have come from the nuclear accident. The Cesium is only isotope 137, and there is no isotope 134. If it had come from F. Daiichi both isotopes would be present, says Gakishuin University professor and researcher Yasuyuki Muramatsu. His research on the mushrooms leads him to conclude the Cesium came from other sources more than 20 years ago. If the Cesium had come from F. Daiichi, the two isotopes would have been in roughly equal concentrations. “The fact that no cesium-134 has been detected proves that the contamination happened prior to the Fukushima nuclear accident,’’ Muramatsu, 62, said. “It is from nuclear weapons tests conducted by the Soviet Union and China from the late 1940s to the late 1960s, and from the Chernobyl accident in 1986.” In the 1990s, he and his team studied the effects of tiny levels of Cesium that floated in from Chernobyl. They found some mushrooms had more than 100 Bq/kg at the time, but there were no legal limits worthy of making their findings public. No one would have cared 20 years ago.
When Aomori Prefecture’s wild mushroom Cesium levels were found to be 120 Bq/kg in April, a ban was placed on their sale and consumption. Later, domestically-grown mushrooms grown in Aomori City were tested at 107 Bq/kg, so all of the prefecture’s mushrooms were added to the government’s ban on consumption and sales. In all, ten Prefectures have suffered the same government restrictions. An Aomori restaurant owner was forced to stop using Aomori mushrooms in her establishment due to the ban, but she questioned what was happening, “How can the mushrooms be contaminated when the city is so far away from the nuclear power plant?” She has been using more expensive ones shipped in from other parts of Japan that have no mushroom bans. Now, she doesn’t know what to do. Professor Muramatsu says that mushrooms grown in the vicinity of F. Daiichi will surely have accident-spawned Cesium, but he wonders how many other Prefectures like Aomori have restrictions because of levels of non-Fukushima Cesium above the new standards. The Health Ministry says, “We need to observe changes over the long term, and we want to work with relevant organizations to study (this issue).”
They should not only look at Muramatsu’s research, but also seriously reconsider the new national standards on radiological content in foods. Numerous prestigious international research organizations like the IAEA and UNSCEAR recommend the limits on radioactive Cesium levels be 1000 Bq/kg. Before the Fukushima accident, Japan generally followed the international guidelines. Because of public radiation fears broadcast in the Press after the accident, Japan cut the limit in half hoping it would have a calming influence. But the level of fear remained high, so Tokyo lowered the limits to one-tenth of the international standards. One might ask how safe are the international standards? All regulatory limits for radiation exposure are set at least 10 times lower than the hypothetical level at which negative health effects might occur, and this includes internal doses from ingestion of food and drink. The international limits are very safe. Regardless, in the hope of making their politically-vocal radiophobic demographic feel safe, Japan lowered their standards by an additional order of magnitude.
This writer has gone on record saying that Japan’s new radiation standards are unrealistically restrictive. They were not based on scientific evidence. They were created out of perceived political expediency by the regime that was summarily voted out of office last month. Thus, they are flatly arbitrary. Suddenly, we find their limits are below the levels that have safely been the case in Aomori Prefecture for at least two decades…if not considerably longer. I am convinced that as time passes, more and more evidence revealing the ridiculous nature of these too-low limits will be uncovered, not only in food contamination levels but also with their 1 millisievert per year whole body limit unnecessarily keeping Fukushima evacuees from their undamaged homes. Japan has never run a comprehensive natural background study, so they don’t know what is normal for their country and what isn’t. Whole body exposure limits, both internal and external, might be better based on the highest natural background levels where historically-healthy Japanese people have lived healthy lives for decades…centuries…in some cases millennia. The contamination levels in foodstuffs should reflect this naturally-occurring-in-Japan whole body limit. It will take considerable time and effort because they will be starting from zero, if you will, but doing anything less is disrespectful to the Japanese people.
But, what should be done in the while this research is performed? Tokyo’s former political regime went too far and allowed political expediency to confound reason. The new administration should tell the people of Japan that the old governmental regime made a horrible mistake. Japan should raise its food contamination standards back to the 500 Bq/kg level invoked soon after the Fukushima accident, at the very least. They say we should learn from our mistakes. Japan’s new government should learn from this mistake made by their political forerunners.