Natural radiation environment in China

摘要

The Ministry of Health, China conducted national survey of natural radiation level in 1980s. The following items are included in the nationwide survey. Cosmic radiation―outdoor average absorbed dose rate from cosmic radiation is 37.4 nGy/h. The highest average absorbed dose rate from cosmic radiation―116.2 nGy/h is found in Tibet. Terrestrial gamma radiation―outdoor average absorbed dose rate from terrestrial gamma radiation is 81.5 nGy/h in China. The highest average absorbed dose rate ―188.0 nGy/h is found in Xunwu County, Jiangxi Province. Radionuclide content in soil―average contents of ~(238)U, ~(226)Ra, ~(232)Th and ~(40)K in Chinese soil are 38.5, 37.6, 54.6 and 584 Bq/kg, respectively. Yangjiang County of Guangdong Province has the highest average radionuclide contents in soil for ~(238)U, ~(226)Ra and ~(232)Th. Radon level in air―average indoor radon level in China is 26.2 Bq/m~3. Average outdoor radon level is 13.5 Bq/m~3. Radon content in water ? drinking water in some cities―9.04 kBq/m~3; surface water―1.26 kBq/m~3; well water―16.7 kBq/m~3; deep well water―34.9 kBq/m~3; hot spring water―278.9 kBq/m~3. There are some special areas in China, in which natural background radiation is obviously higher than in neighboring regions. Some epidemiological studies are going on in those areas. We hope to have more cooperation with other scientists in these areas.