Annual effective dose associated with radioactivity in drinking water from tin mining areas in North-western Nigeria

Abstract

Mining of minerals increases the risk of exposure to natural radionuclides by exposing them to the outer surface of the earth. The risk increases when these radionuclides are migrated into the bodies of water that have been used for drinking purposes. This work was carried out to assess the radionuclides concentration in drinking water from tin mining areas in North-western Nigeria. Water samples were collected and the activity concentration of 40K, 232Th, 226Ra, and 222Ra were analyzed using a high-purity germanium detector and a liquid scintillation counter respectively. The mean activity concentrations were found to be 3.57 ± 2.1, 4.0 ± 2.2, 7.6 ± 3.7 and 5.8 ± 3.3, 4.4 ± 2.7, 6.2 ± 4.2 Bq/l in surface and groundwater for 226Ra, 232Th, 40K respectively. These values exceeded the recommended value of 1.00 Bq/l in drinking water set by the International Atomic Energy Agency. The activity concentrations of radon varied from 0.75 to 17.08 Bq/L with a mean value of 12.50 Bq/l. The obtained mean value exceeded the recommended value of 11 Bq/l set by the United State Environmental Protection Agency as the level of radon in drinking water. The calculated annual effective dose due to radon and 226Ra, 232Th 40K from the studied water are 2.66 μSv/y and 3.30 μSv/y respectively. These values are lower than the maximum allowable value of 100 μSv/y as a radiation dose received from drinking water set by the World Health Organisation and the United Nations Scientific Committee on the Effect of Atomic Radiations. Therefore, both the surface and groundwater from the study areas can be used for drinking and other domestic purposes as it could pose no significant radiological health hazards.