Assessment of Radioactivity of Some Surface Soils in Gboko Local Government Area of Benue State and Health Implications, North Central Nigeria

The activity concentrations of some radionuclides in soil samples were collected from10 locations in Gboko local government of Benue State have been determined using the Gamma ray Spectroscopy？ (Model No: 3M3/3). The soil activity ranges from 58.88 to 64.49Bq/Kg for 40K, 3.33 to 5.31Bq/Kg for 238U and 4.66 to 8.25Bq/Kg for 232Th respectively for the urban areas. In the rural areas, the activity concentration ranges from 55.42 to 66.26Bq/Kg for 40K, 3.77 to 5.55Bq/Kg for 238U and 4.21 to 10.02Bq/Kg for 232Th respectively. The mean absorbed dose rate in air ranges from 6.78nGy/h in Gboko – East to 9.37nGy/h in Mkar - Hill while the annual effective dose for the same areas varied from 0.01mSv/y in three sites to 0.01mSv/y in Mkar - Hill. The estimated absorbed dose rate in air varied from 6.73nGy/h in BCC to 10.28nGy/h in Gboko – Poly with annual absorbed dose of 0.01mSv/y in BCC to 0.03mSv/y in Ape - Inumbu. The results showed that, the annual effective dose rate is much lower than 0.1mSv/y maximum permissible limit recommended for humans by WHO, (2009). It is also lower than the safe limit of 0.07mSv/y permitted by UNSCEAR,( 2009) for individual members of the public. This reach work indicated that the samples soil may have not been impacted radio logically.