Update, or rather, review: The numbers are much higher than what was found in the area inside the 10-kilometer radius (actually 2 kilometers from the plant, 68 becquerels/kilogram). The number for strontium-90 in Akogi in Namie-machi (250 becquerels/kilogram) is approaching the number found at Fukushima I Nuke Plant (570 becquerels/kilo).
Does it take that long to analyze the soil samples for strontium? (I know, I know...)
Asahi Shinbun reports that radioactive strontium was detected in soil as far away as 62 kilometers from the plant. The samples were taken between April 10 and May 19.
What's hilarious in the article is the so-called expert's comment, basically saying "Where there's cesium there's strontium. So of course we see strontium in the soil. But don't worry, if you don't eat much cesium, observing the government's provisional limit which may or may not stays the same, you're OK."
Well, he had been awfully quiet about that bit of information until asked by the Asahi reporter who wrote the piece. Disingenuous of Asahi Shinbun also; it is the first time that I remember, that any newspaper has said "where there's cesium, strontium is supposed to be there also." Asahi had a chance to say so from the day one, but didn't bother.
Non-government, non-experts like the rest of the Japanese already suspected it from long ago, particularly when they knew that strontium, plutonium, uranium, even americium, of Fukushima origin had been detected in the US.
From Asahi Shinbun (12:00AM JST 6/9/2011):
The Nuclear Safety Commission: "We knew that."
文部科学省は８日、放射性ストロンチウムが東京電力福島第一原子力発電所から６２キロ離れた福島市など、福島県内１１カ所の土壌で新たに検出されたこと を明らかにした。放射性セシウムが検出されたところでは、微量に見つかるとされており、それが証明された形だ。放射性ストロンチウムには半減期が長いもの があって、体に入ると長期間影響を及ぼす可能性があり、監視が必要だ。
The Ministry of Education and Science disclosed on June 8 that radioactive strontium had been detected at 11 locations in Fukushima Prefecture, including Fukushima City which is 62 kilometers away from Fukushima I Nuclear Power Plant. A small amount of strontium is supposed to be found where radioactive cesium is also found, and now it's been proven so. Some strontium radioisotopes have long half-life, and they could affect the body for long time if ingested.
Radioactive strontium was found from soil samples taken from April 10 to May 19. In Fukushima City, strontium-90 with half-life of 29 years was found in 77 becquerels per kilogram, and strontium-89 with half-life of 50 days was found in 54 becquerels per kilogram.
最も多かったのは浪江町赤宇木で、それぞれ２５０ベクレルと１５００ベクレル。北西部に３６キロ離れた飯舘村では１２０ベクレルと１１００ベクレルで、 これまでに２０キロ圏内で検出されていた値よりも高かった。ほかに田村市、広野町、川内村、南相馬市、二本松市でもストロンチウムが検出された。文科省は 採取した土壌をさらに細かく分析するという。
The highest numbers come from the Akogi district in Namie-machi, with 250 becquerels/kg strontium-90 and 1,500 becquerels/kg strontium-89. In Iitate-mura, 36 kilometers northwest of the plant, 120 becquerels/kg strontium-90 and 1,100 becquerels/kg strontium-89 were detected; these amounts were even higher than those that had been detected earlier within 20 kilometer radius from the plant. Radioactive strontium was also detected from the soil samples from Tamura City, Hirono-machi, Kawauchi-mura, Minami-Soma City, Nihonmatsu City. The Ministry of Education and Science will further analyze the soil samples.
Radioactive strontium melts at a higher temperature than cesium to be volatilized. The fact that strontium has been detected would mean that the reactor core started to melt from the early stage of the accident, and then radioactive materials were released.
ストロンチウムは人体に入ると、骨にたまる性質がある。原子力安全委事務局の加藤重治・内閣府審議官は「ストロンチウムはセシウムに対して一定の割合で 存在している。そのため、食べ物からの取り込み分はセシウムの規制値を守っていればストロンチウムについても影響はない。ただ、土壌から体内に取り込まな いよう注意すべきだ」と話している。
Once ingested, strontium tends to accumulate in bones. The Japanese government's Nuclear Safety Commission's spokesman Shigeharu Kato says, "Strontium exists at a certain ratio to cesium. Therefore, as long as the safety limit for cesium in food is observed, there is no ill effect from strontium. But caution is necessary not to ingest it from the soil."
I guess they didn't feel like announcing it.