Baseline Study and Statistical Analysis of Natural Radioactivity, Radon, and Soil Properties in Proposed Underground Mine in Prestea Huni-Valley Municipality of Western Region, Ghana

Abstract

The study aims to establish a natural radioactivity and radon gas baseline for the proposed concession for an underground gold mine in the Bonteboni within the Prestea Hun-Valley Municipality of the Western Region, Ghana. The CR-39 and HPGe detectors were used to determine radon gas and 226Ra, 232Th, and 40K concentrations with sieving and weighing methods to determine the porosity and composition of soils, in sixty (60) soil samples and one hundred twenty (120) dwellings. The studied data for dwellings were found to range from 82.9 to 165.8 Bq/m3 (131.0 ± 12.7 Bq/m3). The radionuclides of 226Ra, 232Th, and 40K and soil radon gas were in the range of 12.5–35.9 Bq/kg (23.3 ± 0.9 Bq/kg), 35.8–134.7 Bq/kg (83.2 ± 3.7 Bq/kg), 30.4–324.6 Bq/kg (143.2 ± 11.3 Bq/kg) and 8.0–19.3 (14.7 ± 0.4 µBqm−2 h−1), respectively. Indoor radon gas was found in increasing order in dwelling types as clay > sandcrete > wooden while the natural radionuclides were also found to follow the order 40K > 232Th > 226Ra. Sixty-three dwellings obtained indoor radon levels above the World Health Organization’s recommended limit of 100 Bq/m3. Fifteen locations had levels of the radionuclides 226Ra and 232Th exceeding guidelines set by the UNSCEAR. The effective doses due to natural radionuclides were found to be less than 1 mSv/yr with thirty-five locations having values greater than the ICRP’s lower recommended limit of 3 mSv/yr. The ventilation systems were found to have a greater influence on the indoor radon concentration in different dwellings. The linkage and composition analysis between the porosity and soil particles indicated a direct impact on natural radionuclides and radon levels, thereby influencing the amount of radiation exposure to the public and environment.