Ononugbo C.P, Avwiri G.O and Agbalagba, E.O
Keywords: River State, radioactivity, health impacts, soil and water land filling, spectrometer
Abstract: The objective of present study was to evaluate the activity concentrations of 238U, 232Th and 40K and excess lifetime cancer risk due to gamma exposure of soil and ground water around open landfills in Rivers State, Nigeria. A total of 21 soil and 17 ground water samples were collected around Aluu and Rumuolumeni landfills. Soil and water samples were analyzed using a well calibrated gamma-ray spectrometry (NaI (Tl)) detector system after they have reached radiogenic equilibrium. The mean specific activity concentration of 238U, 232Th and 40K for soil samples were 48.44± 4.08 Bqkg-1, 39.68±2.48Bqkg-1 and 416.48±11.23Bqkg-1 in Aluu landfill and 22.99± 1.04Bqkg-1, 12.94± 0.84Bqkg-1 and 169.11±5.46Bqkg-1 in the Rumuolumeni landfill respectively, while in water they were 10.58± 1.09Bql-1, 10.30±1.02 Bql-1 and 173. 78±21.32Bql-1 in Aluu landfill and 11.01±3.44Bql-1, 16.26± 3.77Bql-1 and 225.88± 36.10Bql-1in Rumuolumeni landfill respectively. The mean activity concentration of 238U, 232Th and 40K around Aluu landfill were higher than the permissible values. The radiation hazard indices calculated for the soil samples around Aluu landfill were higher than their permissible values. All other radiation hazard indices calculated in all the samples (soil and ground water) from both Aluu and Rumuolumeni landfill were below unity. Based on our present study, we concluded that activity concentration of 238U, 232Th and 40K in soil and ground water samples were high and Excess lifetime cancer risk calculated for all the samples analyzed were higher than the safe limits, therefore long term radiation exposure of the residents around Aluu and Rumuolumeni landfill will pose significant health threat, thus the ground water from these study areas should be treated for radionuclide before ingestion to reduce the radiation risk
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