Influence of open cast mining on radiological health risk of agricultural soils around Adudu lead-zinc mine, Nasarawa State, Nigeria

Various fields of science have focused on the level of natural radionuclides in the environment since they are responsible for terrestrial background radiation exposure to members of the public. Gamma ray spectrometry with high purity germanium (HPGe) detector was used to measure the activity concentrations of natural radionuclides {U-238 (Ra-226), Th-232 and K-40} in one hundred and ten (110) composite soil samples collected from eleven (11) studied sites around lead (Pb)-zinc (Zn) mine. Result showed that the mean activities of U-238 (Ra-226), Th-232 and K-40 in the investigated soils varied between 28.49 +/- 2.93-72.95 +/- 7.07, 33.97 +/- 4.09-105.78 +/- 9.91 and 27.37 +/- 1.87-853.16 +/- 45.95 Bq/kg respectively. The activity concentrations of the analyzed natural radionuclides and their evaluated radiological health hazard parameters for soils around the mine, were above global average values and higher than those of control soil. The levels of U-238 (Ra-226), Th-232 and K-40 and the values of assessed radiological health hazard parameters for the control soil, were all lower than the global average values. This research showed that open cast mining of Pb-Zn in Adudu significantly increased the radiological health risk posed to the mine workers and community dwellers.