From the July 2009 Scientific American Magazine.
Did China's Nuclear Tests Kill Thousands and Doom Future Generations?Radioactive clouds hung over villagers as China detonated nuclear bombs in the air for four decades
By Zeeya Merali
Enver Tohti remembers the week that it rained dust. That summer of 1973 he was in elementary school in Xinjiang Province, China’s westernmost region, which is inhabited mostly by Uygurs, one of the country’s minority ethnic groups. “There were three days that earth fell from the sky, without wind or any sort of storm. The sky was deadly silent—no sun, no moon,” he recalls. When the kids asked what was happening, the teacher told them that there was a storm on Saturn (its Chinese name translates into “soil planet”). Tohti believed her. It was only years later that he realized it was radioactive dust raised by the test detonation of a nuclear bomb within the province.
Three decades on, Tohti, now a medical doctor, is launching an investigation into the toll still being taken—and one that the Chinese government steadfastly refuses to acknowledge. A few hundred thousand people may have died as a result of radiation from at least 40 nuclear explosions carried out between 1964 and 1996 at the Lop Nur site in Xinjiang, which lies on the Silk Road. Almost 20 million people reside in Xinjiang, and Tohti believes that they offer unique insight into the long-term impact of radiation, including the relatively little studied genetic effects that may be handed down over generations. He is establishing the Lop Nur project at Sapporo Medical University in Japan with physicist Jun Takada to evaluate these consequences.
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In the early 1990s Takada, who studied radiation effects from tests conducted by the U.S., the former Soviet Union and France, was invited by scientists in Kazakhstan, which borders Xinjiang, to evaluate the hazard from Chinese tests. He devised a computer model to estimate fallout patterns using Soviet records of detonation size and wind velocity as well as radiation levels measured in Kazakhstan from 1995 to 2002. Takada was not allowed into China, so he extrapolated his model and used information about the population density in Xinjiang to estimate that 194,000 people would have died as a result of acute radiation exposure. Around 1.2 million received doses high enough to induce leukemia, solid cancers and fetal damage. “My estimate is a conservative minimum,” Takada says.
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Tohti and Tanaka’s Lop Nur project could fill in many gaps left open by analyses of other mass radiation poisonings. In studying the Chernobyl aftermath, Møller and his colleagues found that animal populations in the area still show a significant decline in numbers and an increase in genetic mutations, in contrast to earlier reports of recovering wildlife.
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