今月初東京世田谷區一些位置有高放射量(下)

Recently the NHK News reported the following:

東京・世田谷区で検出された１時間当たり２．７マイクロシーベルトという放射線量は、文部科学省が積算の放射線量を計算する際に用いている、１日のうち、屋外で８時間、屋内で１６時間過ごすという条件で計算すると、１日の被ばく量が３８．８８マイクロシーベルト、１年間にすると１４．２ミリシーベルトになります。これは国が避難の目安としている年間の放射線量の２０ミリシーベルトを下回っています。計画的避難区域に指定されている福島県の飯舘村役場では、１２日、移動式のモニタリングポストを使って計測された放射線量が１時間当たり２．１マイクロシーベルトで、世田谷区の値はこれよりもやや高くなっています。首都圏では、比較的高い茨城県の北茨城市で、１２日、０．１４マイクロシーベルトが計測されています。放射線影響研究所の長瀧重信元理事長は「文部科学省などによる上空からの測定では、世田谷区では放射線量の高い場所は確認されなかったので、このような値が出たことに驚いている。ただ、地形や天候の関係で局地的に高い線量になることはあり得ると思う。周辺の土壌や草木などから放射性物質の種類を調べたり、どこから放射線が出ているのか調べて原因を突きとめるとともに、ほかにもこうした場所がないか調査する必要がある」と話しています。
(試譯文)
Based on the radiation dosage of of 2.7-micro sievert per hour detected in the Setagaya-district of Tokyo, if it was used to calculate the condition of spending 8 hours outdoor, 16 hours indoor in one day as adopted by the Ministry of Education, Culture, Sports, Science and Technology, it was calculated that the radiation dosage of total exposure for one day would be 38.88-micro sievert, and in one year would become a 14.2-mm sievert. This was less than the 20-mm sievert of the annual dose of radiation which the country set in the refuge standard. In the Iitate village office in Fukushima Prefecture that had been specified as the planned refuge zone, the radiation dosage measured using the portable monitoring post on the 12th was 2.1-micro sievert per hour, in comparation Setagya-district had a little higher dosage. In the metropolitan area, on the 12th, 0.14-micro sievert was measured in the comparatively high location of Kita-Ibaraki in Ibaraki Prefecture. Nagataki Shigenobu the former chairman of the board of directors of Radiation Effects Research Foundation said "based on the measurement collected from the sky by the Ministry of Education, Culture, Sports, Science and Technology etc., the high radio-active value came out of Setagaya-district could not be checked. The high radiation dosage that came out was surprising. However, I think that there can be high dosages in certain locations due to the relationship between geographical feature and the weather. While investigating the kind of radioactive material from surrounding soil, plants, etc., or investigating where radiation has come from and tracing the cause, it is also necessary to investigate whether there is any other such place."

So, it is true that some locations in Tokyo are emitting radiation with a dosage higher than expected. For public safety reasons, I hope the local authorities could handle the matter urgently.