A five-year study of the incidence of disease among residents of radiation-contaminated buildings was recently completed, showing that the possibility of chromosome aberration -- damage to DNA -- was proportional to long-term exposure to low-dose radiation.
From November 1995 to June 2000, a research team at National Yang Ming University (陽明大學) kept track of more than 4,100 sample people who once lived in buildings that had been constructed in Taipei City between 1982 and 1983 using radioactive steel reinforcing bars.
A high incidence of diverse cancers was discovered among samples taken from the group.
The researchers said that cancer could be induced by various factors, including personal lifestyle and environmental and occupational conditions. Exposure to radiation exceeding safety limits is also a factor that deserves close attention, they said.
"We found that DNA damage and chromosome aberration was closely related to samples' long-term exposure to low-dose radiation," Chang Wu-shou (
The 4,100 sample patients, who have been receiving treatment at Taipei Municipal Jen-ai Hospital, are among some 7,800 residents recorded by the Taipei City Government as victims of radiation contamination.
Eighty-nine of the 4,100 samples were diagnosed with cancer, including cervical cancer, breast cancer, liver cancer, leukemia and thyroid cancer. Researchers said that high incidence of the disease might be attributed to chronic low-dose radiation exposure.
Over the course of the research period, 39 of the 89 cancer sufferers died.
Researchers said that the situation did not mean that the mortality from cancer in the group was higher than that in other population groups because there was no direct link between cancer and the patients' exposure to low-dose radiation.
Researchers, however, concluded that excessive radiation did have a negative impact on humans.
"For example, we discovered that the height of children who had been exposed to radiation [exceeding the safety limits] was generally below average," said Chang, an environmental health sciences professor. He also said that the incidence of cataracts (白內障) among children who lived in radiation-contaminated buildings was higher than the national level.
"We also concluded that radiation causes damage to white blood cells, weakening people's immune systems," Chang said.
Unpleasant reminder
Chang's study, supported by the National Health Research Institute (
Officials from the council contacted Chang several times, asserting that his research on low-level radiation would not result in any new scientific discoveries. They told him that a low dose of radiation has been demonstrated to be beneficial to humans.
Chang, however, said the council should be ashamed of itself for discouraging him from conducting his research because Taiwan was the only country which could provide such samples for medical research.
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