Tritium is a radioactive isotope of hydrogen which occurs in precipitation. In groundwater studies tritium measurements give information on the time of recharge to the system; the tritium content of precipitation being used to estimate the input of tritium to the groundwater system. At Yola, the tritium contents in precipitation and groundwater samples from boreholes were measured during the rainy season for 2 consecutive years. In the precipitation it was found to be 9.8 ± 0.8 TU. In the groundwater the tritium content ranges from 3.0 to 9.0 ± 0.8 TU. These values indicate that the groundwater systems around Yola contain a mixture of old recharge and recent recharge i.e. water younger than 50 years.

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The Vertical Electrical Sounding (VES) technique was used to investigate the sub-surface layering in some selected villages in Chikun LGA of Kaduna State with the aim of determining the configuration of the aquifer underlying the region. The result of the interpreted VES data suggests that the area is underlain by three to five layers. The geologic sections derived from the analyzed geoelectric section suggest that the alluvial deposits of sand, silt and sandy clay as well as the weathered and fractured basement rocks constitute the aquifer in the areas. The average thickness of the aquifer was found to be 25m. The geoelectric section generated also suggest that the resistively values of the aquifer components range from 100 Ωm to 250 Ωm for the alluvial deposits to an average of 50 Ωm to 350 Ωm for the weathered/fractured basement formations. Results obtained for the pumping tests and transmissivity values of boreholes drilled shows that the area's aquifer are capable of producing at least 0.75l/s i.e. 2.7m 3 /hr of portable water.

This study assessed gamma radiation from 232Th, 226Ra and 40K. Twelve soil samples collected from the study area were analyzed using Nal (TI) detector. Mean concentration for 40K, 232Th and 226Ra were found to be 483.97±7.32 Bq/kg, 28.43±5.30 Bq/kgS and 66.84±2.02 Bq/kg respectively. Absorbed Dose Rate ranged from 44.85 nGy/h to 90.71 nGy/h with a mean of 73.68 nGy/h. Effective Dose Rate ranged from 0.055 to 0.111 msv/yr with a mean of 0.090 mSv/y. The Internal and External Hazard Indices ranged from 0.271 to 0.533 Bq/kg with the mean of 0.435 Bq/kg and 0.289 to 0.675 Bq/kg with the mean of 0.512 Bq/kg respectively. It can thus be concluded that the radiation dose of the study area is minimal and seems to have low exposure for the inhabitants in and around the contaminated areas. It is therefore recommended that regular radiation monitoring exercises should be conducted on the processing sites to prevent the inhabitants of the area from high radiation exposure due to direct inhalation of finely divided particulates and dust comprised of the above-mentioned radionuclides.

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