6 Mar (NucNet): Based on radiological data collected so far the radiation health effects of the March 2011 Fukushima-Daiichi nuclear accident should be “very minimal” for both the public and workers, radiation health experts told a meeting in the US.
Kathryn Higley, professor of radiation health physics in the department of nuclear engineering at Oregon State University, told an event hosted by the Health Physics Society that from a radiological perspective, “we expect the impact to be really, really minor”.
She said: “And the reason for that is we understand how radionuclides move through the environment, how they disperse and how people can be exposed. Because we understand that we are able to make decisions to block exposure.”
Ms Higley told the society, a scientific organisation of professionals that specialise in radiation safety, that prompt evacuations and food monitoring by the Japanese authorities had helped reduce the public’s exposure.
“Because of those actions, the Japanese government was able to effectively block a large component of exposure in this population,” she said.
Robert Gale, visiting professor at Imperial College London, pointed out that although approximately 20,000 people died from the 2011 Tohoku earthquake and subsequent tsunami, none of those deaths were attributable to radiation from the Fukushima-Daiichi accident.
Mr Gale presented preliminary data on the 10,000 inhabitants near the Fukushima-Daiichi plant thought to have received the highest doses of radiation showing that:
• 5,800 received doses less than 1 millisievert (mSv);
• 4,100 received doses between 1 and 10 mSv;
• 71 received doses between 10 mSv and 20 mSv;
• 2 received doses between 20 mSv and 23 mSv.
By comparison, he said, each year a resident of the US receives an average total dose from background radiation of about 3.1 mSv.
Mr Gale said it was important to translate these doses into something the general public could easily understand. These radiation doses indicate an “incredibly small” increase in risk of death from cancer of only 0.001 percent for a member of the Japanese public, he said. The increased risk of cancer incidence would be only 0.002 percent for a member of the Japanese public.
Such a small increase in the cancer rate would make it very hard to scientifically verify an increase in cancers that could be directly linked to the Fukushima-Daiichi accident.
John Boice, professor of medicine at Vanderbilt University School of Medicine and president nominee of the National Council on Radiation Protection and Measurements, said the exposure to the population is very, very low. “As such, there is no opportunity to conduct epidemiological studies that have any chance of detecting excess [cancer] risk. The doses are just too low.”
Despite this, the Japanese government is conducting various large-scale studies of the public’s exposure to radiation to “reduce anxiety and provide assurance to the population,” Mr Boice said.
See the society’s Fukushima-Daiichi information page: http://hps.org/fukushima