an evaluation of the equivalent dose due to natural radioactivity in the soil around the consolidated tin mine in baukuru-jos, plateau state of nigeria

background: the equivalent dose in the human body due to the natural gamma-emitting radionucides (238u, 232th and 40k) in the surface soil surrounding the consolidated tin mine site in bukuru-jos, nigeria has been determined in this study. materials and methods: measurements of the soil natural radioactivity were made using a multi-channel pulseheight analyzer (canberra series 10 plus) coupled to a 76 mm×76 mm nal (tl) scintillation detector. results: the mean concentrations obtained for each of the radionuclides is 35.4±17.6 bq/kg for 40k 776.0± 158.0 bq/kg for 238u and 2.72±0.58 kbq/kg for 232th. the mean absorbed dose rate due to natural radioactivity calculated at a height of 1.0 m above the ground is 2.16 µgy/hr which converts to an equivalent dose of 3.0 msv/y. conclusion: the results obtained in this study are far above the world average equivalent dose of 0.41 msv/y but lower than the annual limit of 20 msv/y for radiation workers but still represents a health risk to workers on the site.