A Japanese research center that has studied atomic bomb survivors for 35 years will send scientists to investigate the health effects of radiation from the Fukushima power plant north of Tokyo.
Two doctors from the Radiation Effects Research Foundation may leave this week for the Tokyo Electric Power Co. atomic plant, said Evan Douple, the center’s associate chief of research. Additional people may follow to help measure radiation levels and work with local health officials to better understand the effects of exposure, he said.
Japanese Prime Minister Naoto Kan said the risk of further radiation leaks is rising after a third explosion rocked the Dai-Ichi plant, and he warned people living within 30 kilometers to stay indoors. Scientists from Douple’s center may be called upon to test people for genetic defects.
“We need to know what kind of dose levels are expected” as a consequence of the explosion, Douple said in a telephone interview yesterday. Studies from survivors of the atomic bombs dropped on Hiroshima and Nagasaki 65 years ago suggest “substantial doses” are needed to increase the risk of cancer, he said.
The foundation, established in 1975 two miles from the epicenter of the Hiroshima blast, runs the world’s largest and longest scientific investigation of a population exposed to radiation. Its research has helped set international guidelines for the International Committee on Radiological Protection.
The radioactivity measured at a building housing the reactor was less than 2 percent of the level known to be harmful, Hidehiko Nishiyama, deputy director-general Japan’s Nuclear and Industrial Safety Agency, said yesterday.
“From the radiation released so far, the public health risk appears to be quite small,” said Gregory Hartl, a spokesman for the World Health Organization in Geneva.
Authorities in Japan earlier ordered people within a 20- kilometer radius to evacuate as a precaution.
Radiation is measured in sieverts. Radioactivity around the reactor building was about 0.00002 sieverts per hour, Nishiyama said.
A typical chest X-ray yields 0.0001 sievert and a full-body CT scan a dose of 0.045 sievert, according to the Health Physics Society at the University of Michigan. Levels above 0.1 sievert have been linked with increased cancer risk, Douple said.
“We are not really anywhere near that, according to the numbers we’ve seen,” Douple said.
Exposure to 1 sievert of radiation can cause hemorrhaging, 4 sieverts can cause death within two months, and 2,000 sieverts can cause loss of consciousness within minutes and death within hours, according to the U.S. Environmental Protection Agency.
Doctors at the Radiation Effects Research Foundation found atomic-bomb survivors in Japan had a 45 percent higher death rate from leukemia and an 8 percent higher death rate from cancerous tumors than the general Japanese population.
The rate experienced by Hiroshima and Nagasaki survivors is about 0.08 fatal cancers per 1 sievert of dose, according to the book “Nuclear Wastelands: A Global Guide to Nuclear Weapons Production and Its Health and Environmental Effects.”
Staff members from the Radiation Effects Research Foundation will probably work in the vicinity of the explosion site, recording ambient radiation levels. They may also look for chromosomal damage in tissue samples taken from people who may have been exposed to radiation, Douple said.
Data on radiation levels may be ready in the next few days, helping authorities gauge the number of people who may have been affected, he said.
“We’ll need to know what populations are at risk, and the number,” Douple said.
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