Buried bottle determined to be radiation source

Japan's science ministry has determined that high radiation readings taken near a supermarket in Tokyo were caused by radium in a buried bottle.

On Wednesday, workers removed the reagent bottle along with some contaminated underground soil from the parking lot of a supermarket in Hachimanyama, Setagaya Ward.

After the removal, radiation in the area dropped to 25 microsieverts per hour, which is one-1,600th the previously observed level. The ministry says the source of the radiation was the radium 226 in the bottle.
The radioactive substance is used in cancer treatments and to make fluorescent paint.

Last week, the ministry reported detecting radiation of up to 170 microsieverts per hour at a height of 1 meter above the ground at 2 spots, one at an asphalt parking lot and the other at a sidewalk.

Officials say that during a survey on Wednesday, they found 15 other spots in the same area emitting relatively high radiation. The highest reading was 12 microsieverts per hour. They say all 15 spots registered far less radiation when measured at a height of 1 meter.

The science ministry decided to pile up sandbags at some of the spots to block the radiation.

In the middle of last month, radiation of up to 2,707 microsieverts per hour was observed at another spot in Setagaya Ward. Officials determined that the source of the radiation was some jars in a wooden box under the floor of a vacant house. An analysis indicates that the radioactive material may be radium 226.

Friday, November 04, 2011 10:41 +0900 (JST)