The Yomiuri Shimbun
The government recommendation that people voluntarily evacuate from homes located 20 kilometers to 30 kilometers from the crippled Fukushima No. 1 nuclear power plant came after a nuclear watchdog released forecasts on the spread of radiation.
The radiation forecasts by the Cabinet Office's Nuclear Safety Commission were based on the government's System for Prediction of Environmental Emergency Dose Information (SPEEDI). The measurements are based on the premise that a person was outdoors continually over a certain period.
The data released by the NSC on Wednesday brought to light the fact that there are considerable differences in radiation levels between areas, even within 30 kilometers of the troubled nuclear power plant in Fukushima Prefecture.
Significantly high radiation readings were recorded in some areas outside the 30-kilometer zone, according to the commission, as the spread of radioactive substances depends heavily on geography and wind direction.
"These SPEEDI radiation forecasts point to some radiation diffusion," NSC Chairman Haruki Madarame said at a press conference Wednesday. "Although the government has so far used circular regions to determine evacuation areas, it seems it's time to change how the areas are designated. They should be more detailed."
The Yomiuri Shimbun calculated radiation doses based on data from the Fukushima prefectural government. These calculations were made under the premise a person was outdoors continually from March 14 to 4 p.m. March 24.
The estimates showed a person would have absorbed 620 microsieverts of radiation in Minami-Soma, about 24 kilometers from the nuclear plant, over that period. But the number reached 4,000 microsieverts in Iitatemura, about 40 kilometers northwest of the troubled plant.
Four thousand microsieverts far exceeds the 1,500 microsieverts an average person in Japan is exposed to naturally in a normal year.
These estimates on the spread of radiation correspond closely to the SPEEDI forecasts.
"Lopsided radiation levels at different monitoring points were also reported in the 1986 Chernobyl nuclear disaster," said Prof. Hirotada Hirose of Tokyo Women's Christian University, an expert in disaster prevention and risk psychology.
"The government should've announced the SPEEDI findings earlier than Wednesday," he said. "Deciding on a circular evacuation area and then gradually expanding it can hardly be called scientific."
Radiation exposure specialist Ikuro Anzai, a professor emeritus at Ritsumeikan University, said, "When the government encourages people to leave voluntarily, the socially disadvantaged tend to get left behind."
"Instead of doing things halfway, the government--if it considers evacuation to be necessary--should evacuate residents resolutely," Anzai said. "The government should tell people in advance about probable wind directions and other related information, just like weather forecasts. Evacuation instructions should be issued specifically to areas where significant radiation increases are anticipated."
Another expert called for the government to take disaster victims' quality of life more into consideration.
"For elderly people, health risks caused by the stress of moving out of where they live and the difficulties of life at shelters are often far greater than the risk of developing cancer due to radiation," said Prof. Michiaki Kai of Oita University of Nursing and Health Sciences.
"The central and local authorities should provide disaster victims with assistance appropriate to their needs, which will differ from person to person," he said.
(Mar. 27, 2011)
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