Abstract

Radioactivity level in six soil samples from different boreholes in Zaria, Nigeria was assessed. The presence of ⁴⁰K, ²²⁶Ra and ²³²Th were analyzed using γ -ray spectrometry with sodium iodide thallium, {NaI(Tl)} detector. Mean specific activity of 1020.4 ± 12.4, 123.1 ± 2.3 and 25.7 ± 2.0Bq/kg for ⁴⁰K, ²²⁶Ra and ²³²Th, respectively were obtained. The radioactivity level for each location was calculated to ascertain the risk involved in using these boreholes. This radiation index revealed that all the locations are safe except two locations having radioactivity level of approximately 1.02 and 1.30 Bqkg^-1,respectively, which are well above the world quoted value of unity. This shows that the concentration levels for these two areas are high and it is therefore recommended that none of these boreholes’ water be consumed in order to avoid unnecessary exposure and absorption of dosage of radiation that will be threatening to life.

Key words: Radioactivity level, borehole-soil, γ-ray.