JAPAN: Drawing on research to counter radiation panic

The Japanese government is reaching out to academics to combat growing public agitation over the detection of higher levels of radioactive contamination from damaged nuclear reactors at the Fukushima Daiichi plant after the massive 11 March earthquake and tsunami.

The country's many years of medical research into victims of the atomic bomb blasts at Hiroshima and Nagasaki 66 years ago are also being tapped for clues to the risks of higher radiation levels as confusion reigns over differing responses to the nuclear crisis.

The United States, for example, issued an advisory for its citizens to leave Japan for safety reasons. Some Asian countries are considering banning imports of spinach and milk products after the Japanese authorities reported radioactive substances discovered in leafy vegetables and milk products from Fukushima.

The authorities are being accused of not being transparent enough. Last week Yukiyya Amano, head of the International Atomic Energy Agency, took the unprecedented step of asking Prime Minister Naoto Kan to release more information.

In a bid to stem rising anxiety, the authorities are disseminating independent research from leading Japanese experts.

Professor Shunichi Yamashita, chairman of the department of international health and radiation research at the Atomic Bomb Disease Institute at Nagasaki University, has conducted research on hundreds of victims of radiation from the atomic bombing of Nagasaki in 1945.

He has also observed survivors of the Chernobyl nuclear power plant disaster in the Soviet Union.

Recently appointed health risk management advisor for the Fukushima prefectural government, Yamashita told reporters last week that the threat of radiation exposure from the nuclear crisis was mostly faced by people living within the 20 kilometre zone close to the crippled nuclear power plant and workers in the reactors who are facing high contamination.

The government has demarcated 30 kilometres around the plant as a risk site. "Even in that area, the risk is small and is aimed at children who are more vulnerable to carrying radiation for longer periods of time during which cancer can develop," he said.

Yamashita said the nuclear leak did not pose a danger to the population 20 kilometres from the stricken plant where the current levels of radiation exposure is less than 100 milisieverts or mSv per year according to official figures, putting it below the 'uncertainty level' in expert terminology of having almost no impact on human health.

"As long as the amount of radioactive materials are small (10-50 mSv) then there should not be a problem," he explained.

Research, Yamashita added, indicated that radiation is only one factor in the risk impact for cancer. Others include smoking and genetic susceptibility.

"Such research evidence is what makes it all the more important to judge Fukusima radiation levels more calmly," said Yamashita, who is also a director of the WHO Collaboration Center for Research on Radiation Emergency Medicine.

His view was backed by Dr Kenji Kamiya, Director of the Hiroshima-based Research Institute of Radioactive Biology of Medicine.

Kamiya explained that the Hiroshima nuclear bomb explosion over the city could not be compared to this month's accident at the nuclear plant in terms of the amount of radiation exposure. In the case of the bomb blasts, exposure was instant and at high level.

But he pointed out that over 50 years of research on the Hiroshima tragedy could help in the management of risk and in developing measures to prevent contamination.

"We have the basic data of radiation effects so we can apply and assess the risk faced today. I would put the risk of cancer from exposure to a 10 kilometre area and mostly for young children," Kamiya said

Nonethless, the Japanese government has stopped production and halted the sale of vegetables such as spinach. The Tokyo Metropolitan government has begun distributing bottled water to families with young children who live in Tokyo and five neighbouring cities.

On Wednesday, the Japanese government called on people in Tokyo to be calm when bottled water containers were swept from supermarket shelves after the metropolitan office reported radioactive iodine exceeded the limit for infants' intake in water at a purification plant, apparently because of the nuclear accident 250 kilometres from the capital.