Elevated Radiation Level in the Center of Tokyo, in Ginza

An elementary school located in Ginza, Chuo-ku, Tokyo was found with a 0.80 microsievert/hour radiation spot, and a kindergarten, also in Chuo-ku, was found with 0.56 microsievert/hour spot. So-called "decontamination" effort using a power washer achieved only a modest success in lowering the radiation levels.

In both cases, the asphalt surface resisted decontamination effort, indicating radioactive materials are no longer on the surface after more than 7 months since the Fukushima I Nuclear Power Plant accident started.

From Tokyo Shinbun Tokyo local edition (10/25/2011):

中央区は二十四日、区立泰明小学校（銀座五）と中央幼稚園（湊二）の敷地内の排水溝などで放射線量を測ったところ、国が除染を行う基準としている毎時〇・二三マイクロシーベルト（一マイクロはミリの千分の一）を超える場所が見つかり、除染作業を実施したと発表した。

Chuo-ku announced on October 24 that Taimei Elementary School (located in 5 Ginza) and Chuo Kindergarten (2 Minato) had high radiation spots that exceeded the level that the national government uses as standard for doing decontamination (0.23 microsievert/hour). It also said the decontamination was carried out.

　区によると、二十一日に同小グラウンドの排水溝の一部で、毎時〇・三一マイクロシーベルトを測定。二十二日に高圧洗浄による除染をした結果、同〇・二二マイクロシーベルトに下がった。しかし、その脇のアスファルト部分で同〇・八〇マイクロシーベルトを検出。再度除染したが、同〇・五六マイクロシーベルトまでしか下がらなかった。

According to Chuo-ku, 0.31 microsievert/hour radiation was measured on October 21 in part of the drain on the school yard of Taimei Elementary. Decontamination was carried out on October 22 using a high pressure washer, and the radiation level dropped to 0.22 microsievert/hour. However, the asphalt surface next to the drain measured 0.80 microsievert/hour, and despite the decontamination it only dropped to 0.56 microsievert/hour.

　同幼稚園でも二十一日に雨どいの下二カ所で、同〇・五六マイクロシーベルトと同〇・四二マイクロシーベルトを検出。除染の結果、一カ所は同〇・二二マイクロシーベルトに下がったが、もう一カ所のアスファルト部分は同〇・四六マイクロシーベルトまでしか下がらなかった。

At Chuo Kindergarten, two locations under the rain gutter were found with 0.56 microsievert/hour and 0.42 microsievert/hour respectively on October 21. After decontamination, one location dropped to 0.22 microsievert/hour, but the other location, asphalt surface, remained high at 0.46 microsievert/hour.

　区は児童らが立ち入らないようにしたほか、今後アスファルトの入れ替えを予定している。

The city carried out measures to keep pupils out of the area, and is planning to replace the asphalt surface.

　区は各地で局所的に高い放射線量が検出されている問題を受け、二十一日から学校や公園で排水溝や植え込みなどの調査を始めたところだった。

In response to the reports of high radiation spots being discovered, the city started on October 21 to measure radiation levels in the drains and shrubs in schools and parks.

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