Sunday, October 16, 2011

Fallout from Fukushima, hot spots in Tokyo

Yesterday, the NYTimes reported very disturbing news from Tokyo: radiation 'hot spots' have been detected by citizen monitors in locations around the city.

Some Tokyo residents bought dosimeters. The Tokyo citizens’ group, the Radiation Defense Project, which grew out of a Facebook discussion page, decided to be more proactive. In consultation with the Yokohama-based Isotope Research Institute, members collected soil samples from near their own homes and submitted them for testing. Some of the results were shocking: the sample that Mr. Hayashida collected under shrubs near his neighborhood baseball field in the Edogawa ward measured nearly 138,000 becquerels per square meter of radioactive cesium 137, which can damage cells and lead to an increased risk of cancer.
Of the 132 areas tested, 22 were above 37,000 becquerels per square meter, the level at which zones were considered contaminated at Chernobyl.
Edwin Lyman, a physicist at the Union of Concerned Scientists in Washington, said most residents near Chernobyl were undoubtedly much worse off, surrounded by widespread contamination rather than isolated hot spots. But he said the 37,000 figure remained a good reference point for mandatory cleanup because regular exposure to such contamination could result in a dosage of more than one millisievert per year, the maximum recommended for the public by the International Commission on Radiological Protection.
The most contaminated spot in the Radiation Defense survey, near a church, was well above the level of the 1.5 million becquerels per square meter that required mandatory resettlement at Chernobyl. The level is so much higher than other results in the study that it raises the possibility of testing error, but micro hot spots are not unheard of after nuclear disasters.

The International Business Times reports that radium stored in a local building, not Fukushima fallout,was responsible for the high radiation readings.

Radioactive element radium-226 is responsible for radiation hotspots in Tokyo, not the Fukushima Daiichi reactor, according to experts.
Local officials, on Thursday, reported that although the Setagaya ward is actually very near the Fukushima reactor,(??---it is??? the great goddess google tells me it is 133 miles) radiation levels (which saw a spike recently) were caused by bottles of radium-226 stored in a wooden house in Tsurumaki 5-chrome.
As published in the official blog of Setagaya Ward Mayor Nobuto Hosaka, the investigating team with the resident's permission entered the house and found one spot with high radiation level. "We The investigating team, according to the official blog of Mayor Nobuto Hosaka, of the Setagaya ward, entered the building (with the resident's permission) and found one spot with particularly high levels and later confirmed that the radiation appeared to be coming from what seemed to be bottles inside a cardboard box underneath the floor.
According to experts, residents of the house - a 90-year-old lady and her daughter - were exposed to the radiation levels approximately 30 times above permissible limits. The residents, however, are clueless about how the bottles containing radium got under the floors of their house.
(italicized comment mine)
However, the IBT story is misleading, generalizing from a single case, already mentioned and discounted as a false alarm in the NYTimes story.

(There was also one false alarm this week when sky-high readings were reported in the Setagaya ward in Tokyo; the government later said they were probably caused by bottles of radium, once widely used to make paint.)
Sadly, these hot spots are predictable (as is the stonewalling by government officials in Japan). Where fall out ends up depends on wind and rain patterns, so a landscape dotted with randomly distributed radioactive spots would be the result. The Japanese people will be enduring radiation exposure from these hot spots for generations to come, since there is no realistic way to evacuate Toyko. The best (though still lousy) option is for the government to confront the problem head on and work with radiation experts to mitigate the damage.

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