Statistical analysis of terrestrial gamma radiation dose rates in relation to different geological formations and soil types of Katsina State, Nigeria

Terrestrial gamma radiation is the major source of outdoor radiation exposure to human being. Because of the variation of underlying geological characteristics of surface soil, the terrestrial gamma radiation dose (TGRD) rates vary significantly with the soil type. This work performed in situ measurements of the TGRD rate for a range of geological formation and soils of Katsina State, Nigeria by using a portable hand-held radiation survey metre, RADOS. The TGRD rates ranged between 45 and 271 nGyh(-1) with an overall mean value of 116 nGyh(-1), which is two times higher than the world average value of 59 nGyh(-1). Geological formation (Silicified sheared rock) was found to have the highest mean TGRD value of 163 nGyh(-1). Likewise, soil type (lithosols, ferruginous crusts and ferruginous tropical soils) appeared to have the highest mean TGRD value of 134 nGyh(-1). One-way ANOVA was used to investigate the variation of the significant difference between the geological formations and soil types with TGRD, which shows the influence of geological formation and soil types on the measured TGRD values of the study area. Measured data could further be used to evaluate the public radiation exposure and in formulating safety standards and radiological guidelines.