[Epidemiological survey in a high background radiation area in Yangjiang, China]

The results of the health survey in a high background radiation area (HBRA) from 1972 to 1990, in Yangjiang, China, are presented in this paper. Radiological measurements of the environmental and human bodies with different methods revealed that 330 mR/a in HBRA and 114 mR/a in the control area (CA) were the doses that annually an individual exposure to the external environmental gamma radiation and effective doses to whole body are 6.4 mSv in HBRA and 2.4 mSv in CA annually. The carcinogenic and mutagenic factors were surveyed. The Results showed that these factors in the two areas were similar. Up till now, no harmful impact induced by natural radiation, based on the data as: cancer mortality from 1,008,769 person-years in HBRA and 995,070 person-years in CA; hereditary diseases and congenial malformations from 13,425 subjects in HBRA and 13,087 subjects in CA; human chromosome aberrations, and immune function of the inhabitants, was found. In addition, in this paper the authors discussed the results of cancer mortality, of chromosome aberrations and of immune function, and analyzed the possible relationship among them. The carcinogenic risk induced by low dose radiation was also estimated and discussed.