Radon, lung cancer risk and environmental geology in Gejiu area

Abstract

The incidence of lung cancer in the Gejiu area of Yunnan Province ranks the first in the world. The radon level (indoor, soil) was measured in the Gejiu area by the SSNTD method from 1990 to 1996. The result indicates an extensive high-level of indoor radon in that area though U and Th are lower in local limestones. The indoor radon level of houses located in the geologic fault zone is 6 times high that 2 km far from the fault zone. The reason probably is that the radon level of soil in the fault is 6–8 times high that 1 km far from the faults. Our data indicate that a lower range of radon levels, 0–100 Bq·m⁻³, exists in healthy families. However, a higher radon level, over 800 Bq·m⁻³, is often found corresponding to that of cancer patients’ homes (the house-owners are suffering from either lung cancer or leukaemia or liver cancer). Obviously, an increase in lung cancer incidence follows an increase in indoor radon level. The risk of cancer induced by indoor radon is no longer an inference, but a fact.