Radon Dynamics and Equivalent Dose Calculations in Groundwater and Aquifer Materials Around Maiganga Coal Mine and Environs, North-Eastern, Nigeria

This study primarily focused on soil (aquifer materials) enrichment by radon and its dispersion into groundwater sources. The population of the Maiganga mining community relied entirely on groundwater for drinking and other domestic uses. Dissolved radon in water and excessive concentration in aquifer materials caused non-smoking cancer of the lungs, which is on the increase in Nigeria. Radon spatial distribution in aquifer materials and groundwater were evaluated in an active mining area (experimental zone) and a location further away from the mines (control point). Highly sensitive radon detector RAD7 was employed in radon measurement to depict radon hazard spatially. The exhalation rate ranges from 7.43-7.43 kBq m-3 with a mean of 25.62 kBq m3 in aquifer materials. While concentration in groundwater ranges from 0.15-77.90 BqL-1 with a mean of 1.35 BqL-1. The estimated effective dose due to radon inhalation ranges surface water, and dust particles at experimental points range from 0.367-1.844 μSv, μSv year -1 with arithmetic mean of 38.302 μSv year -1. While at control points, it varies from 1.484-196.38 μSv year -1 with arithmetic mean of 34.639 μSv year -1. The corresponding annual effective dose because of ingestion in the experimental position ranges from 0.0307-184.464 μSv year -1with an average of 19653.86 μSv year -1. At control points, the annual effective dose due to ingestion ranges from 0.233.1-16.359 μSv year -1 with an arithmetic mean of 3.047 μSv year -1 respectively. Computed values of ingestion and inhalation of radon exhaled in the community showed that over 62% of the total effective dose exceeds the reference values recommended by World Health Organisation and International Commission on Radiological Protection, respectively. Its noteworthy excessive contamination of groundwater by radon is enhance by leaching of the aquifer materials derived from the host rock. Consumption of the contaminated water increases the carcinogenic effects on the lungs. (author)