The most significance naturally occurring radionuclides are uranium (238U), thorium (232Th) and potassium (40K). Distinctive concentrations of these nuclides relate to geological and morphological features of specific locations. Igneous rock and regolith
originating from such rock typically has higher concentrations of naturally occurring radionuclides than sedimentary rock. Sedimentary phosphate and some shale are however exceptions to the rule. Sedimentary phosphate rocks that originated from marine environments are usually characterized by activity concentrations of uranium much higher than those of volcanic and biological rocks(Sahu et al., 2014). Sedimentary phosphate usually contains high amount of uranium with typically concentrations of 1500 Bq/kg(Harb et al., 2008). The mining and refinement of phosphate cantherefore potentially distribute and enhance uranium concentrations
in the environment. High levels of radioactive uranium consequently have an important impact on humans as well as the environment