Radon Risk Assessment and Correlation Study of Indoor Radon, Radium-226, and Radon in Soil at the Cobalt-Nickel Bearing Area of Lomie, Eastern Cameroon

摘要

This study focuses on the measurement of the concentrations of radon (~(222)Rn) indoors and in the soil as well as their ambient dose equivalent rate in the cobalt-nickel bearing area of Lomie in the Eastern region of Cameroon. A total of 98 radon track detectors (commercially RADTRAK2?, Rado-nova Laboratories AB, Uppsala, Sweden) were used for indoor ~(222)Rn measurement. A soil radon detector (MARKUS 10) and a pocket survey meter (RadEye PRD-ER, Thermo Scientific) were used for radon in soil and ambient dose equivalent rate measurements, respectively. Activity concentrations of ~(226)Ra were measured using a high purity germanium detector (HPGe). Annual inhalation and external exposure doses, building materials characteristics, and correlations between indoor ~(222)Rn, ~(222)Rn, and ~(226)Ra in soil were evaluated. Indoor radon concentrations varied from 30 to 300 Bq m~(-3) with the arithmetic mean of 58 Bq m~(-3). All values of indoor radon concentrations were above the world average value of 30 Bq m~(-3) given by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Radon concentrations in soil varied from 3.6 to 63.2 kBq m~(-3) with the arithmetic mean of 25.8 kBq m~(-3). Annual external effective dose varied from 0.23 to 0.72 mSv with the arithmetic mean of 0.41 mSv. These annual external effective dose values were all below the world average value of 0.9 mSv. ~(222)Rn and ~(226)Ra in soil were moderately correlated with R~2 value of 0.69. The excess lifetime cancer risk (ELCR) varied from 1.5 to 16.7 with a mean value of 3.6. This mean is about three times the action level of 1.3 recommended by the United States Environmental Protection Agency (USEPA).