【英语国际】东京横滨两地发现放射性热点

Japanese researchers discovered high levels of radioactive material in concentrated areas in Tokyo and Yokohama, more than 241 kilometers away from the Fukushima Daiichi nuclear plant, as increasingly thorough tests provide a clearer picture of just how far contamination has spread and accumulated after the March disaster.

In Tokyo, a sidewalk in Setagaya ward, in the western part of the city, recorded radiation levels of 2.707 microsieverts per hour, about 50 times higher than another location in Setagaya where the ward regularly monitors radiation levels.

'What's puzzling is that the levels detected on other parts of the same sidewalk were very low,' said Ken Hatanaka, head of the ward's section in charge of radiation monitoring said.

The ward is consulting experts to figure out what to do with the highly contaminated spot, Hatanaka said, noting rainwater and sediments containing radioactive fallout may have been more likely to accumulate in such spots.

Still, officials said the discoveries didn't indicate any immediate danger for residents of Japan's largest cities. Overall levels of radiation in those areas remain very low, even near the sites where the new contamination was found.

In Yokohama, the local government said last month that it detected 40,200 becquerels of radioactive cesium per kilogram of sediments collected from one part of a roadside ditch. By comparison, the Japanese government has banned cultivation of rice in fields found to have more than 5,000 becquerels of cesium per kilogram of soil.

The discoveries come as Japanese researchers, local governments, and residents are stepping up their monitoring.

Juro Osawa

日本研究人员在距福岛第一核电站(Fukushima Daiichi) 241公里之外的东京和横滨两地的人口密集区发现高浓度放射性物质。由于日本采取了更加细致的监测手段，人们对3月份事故发生后核污染传播的距离和累积情况有了更清晰的了解。

在东京西部世田谷区(Setagaya)的人行道附近测出最高1小时2.70微希的辐射量，比世田谷区另外一个定期对辐射水平进行监测的地点的辐射量高出近50倍。

负责监测该区辐射水平的Ken Hatanaka说，让人感到不解的是，在该人行道其他部分检出的辐射水平非常低。

Reuters9月29日，工作人员在位于东京北部的茂木赛车场检测放射性水平。这里即将举办世界摩托车锦标赛日本大奖赛。Hatanaka说，该区正在咨询专家，试图找出是什么原因导致这一地点如此高浓度的污染。Hatanaka 同时还说，这样的地点很容易聚积包含放射性尘埃的雨水和沉淀物。

不过，官方声称上述发现并不意味着日本大城市的居民面临着急迫的危险。那些地区（甚至包括发现新的污染地点附近的地区）的放射性水平依旧保持在很低的水平。

横滨地方政府称，上个月在从路边排水沟的堆积物中检测出放射性铯的浓度达每公斤40,200贝克勒尔。相比之下，日本政府已经禁止在土壤放射性物质铯含量超过每公斤5,000贝克勒尔的水田中栽种水稻。

上述发现是在日本的研究人员、地方政府和居民加大监测力度后做出的。

Juro Osawa


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