March 20 (Bloomberg) -- Japan should expand its testing for cases of cancer from the Fukushima nuclear disaster beyond the thyroid screenings that have yielded 75 potential instances so far, a United Nations rights investigator said.
The thyroid cancer tests being conducted in Fukushima prefecture are based on a narrow understanding of the health effects of radiation, Anand Grover, a UN special rapporteur who surveyed the events surrounding the March 11, 2011 disaster, said today in Tokyo.
Data from victims of the bombing of Hiroshima in 1945 show broader cancer consequences than would be detected by the thyroid tests, said Grover, who didn’t specify potential types of cancer.
The earthquake and tsunami in March 2011 caused the meltdown of three reactors at Tokyo Electric Power Co.’s Fukushima Dai-Ichi atomic plant, the worst civilian atomic disaster since Chernobyl in 1986. About 160,000 people were forced to evacuate because of radiation fallout.
A report on the disaster by the World Health Organization in February last year estimated increased cancer risk for those in the most contaminated areas around the plant, but not elsewhere in Japan. The report also noted that better understanding of the effects of low-dose radiation may alter risk expectations from the Fukushima accident.
“Why don’t we have a urine analysis, why don’t we have a blood analysis?” said Grover, who also recommended that the tests be expanded to a broader geographical area. “Let’s err on the side of caution.”
Expanded testing would also bring emotional relief to parents worried that their children may have illnesses that are going undetected, said Grover, a New Delhi-based civil rights attorney.
Health officials in Fukushima prefecture have tested 254,000 residents aged 18 or under at the time of the disaster and have detected 75 with definitive or suspected thyroid cancer as of Feb. 7, the Asahi Shimbun reported.
Hokuto Hoshi, a doctor involved in the prefectural survey, said the cases aren’t thought to be connected to the Fukushima meltdowns because not enough time has elapsed since the accident for the cancer to develop, according to the Asahi.
Grover also said that the Japanese government should bring radiation levels down to the 1 millisievert per year recommended for public exposure by the International Commission on Radiological Protection.
Japan’s government is preparing to lift evacuation orders in areas with radiation levels as high as 20 millisieverts per year, according to a Feb. 18 presentation by Masako Ogawa, an environment ministry director.
The 20 millisievert per year level is consistent with what is routinely permitted for occupational exposure outside the U.S. and under the 50 millisievert per year level allowed within the U.S., according to Kathryn Higley, who heads the nuclear engineering and radiation health physics department at Oregon State University in Corvallis.
“We can’t really measure radiation impacts (using epidemiological tools) at exposures less than about 100 millisieverts,” Higley said in an e-mail. “That’s what makes it such a difficult conversation to have. If it’s unlikely that you’ll never be able to detect an increased risk, why shouldn’t you be allowed to go home?”
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