Natural radiation exposures for cave residents in China

Publisher Summary To understand the biological effects on human beings due to natural radiation exposures as a final goal, the following radiation measurements were preliminarily carried out in cave dwellings and their surrounding areas in China (Shanxi and Shaanxi provinces). There are many cave dwellings where the radon concentration seems to be high on the Chinese loess plateau. Since the residential mobility is low, this area will be suitable for conducting a case–control study on lung cancer risk and residential radon exposure. According to the careful strategy, natural radiation measurements were preliminarily made in Shanxi and Shaanxi provinces. The case–control study in Gansu province conducted by NCI has shown that the lung cancer risk increased with increasing radon level. According to survey results from the present study, however, the presence of thoron cannot be negligible. In fact, the radon concentration was much lower than that given by NCI. It seems that there are several problems to be solved and new findings to be of interest.