Masaharu Tsubokura, M.D., of the University of Tokyo, and colleagues conducted a study to gauge the level of radiation exposure to residents of the city of Minamisoma, located 14 miles north of the Fukushima Daiichi nuclear plant. “Release of radioactive material into the air, water, and soil raised concern about internal radiation exposure and the long-term risk of cancer in nearby residents,” they write.
Many residents were evacuated after the meltdown, but by August 2011, approximately half had returned. A voluntary screening program for levels of cesium, known to be representative of total internal radiation exposure, was conducted between September 2011 and March 2012 for all residents ages 6 years or older. Total cesium exposure was converted into committed effective dose (sievert, Sv). Common dose-limit recommendations for the public are 1 mSv or less. A total of 9,498 residents enrolled in the study, 24 percent of the registered population on August 15, 2011. The sample consisted of 1,432 children and 8,066 adults. A total of 3,286 individuals (34.6 percent) had detectable levels of cesium, including 235 children (16.4 percent) and 3,051 adults (37.8 percent). Committed effective doses were less than 1 mSv in all but 1 resident (1.07 mSv).
“To our knowledge, this is the first report on internal exposure to cesium radiation after the Fukushima Daiichi nuclear plant incident. In this sample, exposure levels were low in most adults and children tested and much lower than those reported in studies years after the Chernobyl incident. Even the highest levels of contamination observed are below the thresholds for the administration of Prussian blue [an antidote used in the treatment of cesium poisoning],” the authors write.
Read the rest of the story: Health consequences of meltdown, damage to Fukushima nuclear power plants in Japan.