Radiological dose and risk assessment from enhanced naturally occurring radioactive materials in selected high background radiation areas in Kenya

Mining and mineral processing activities enhance the physical, chemical, radiological properties and activity concentration of naturally occurring radioactive materials such that there exists a potential for redistribution and contamination of media; increased environmental mobility and leaching of radionuclides in soils and ground water; elevation of radionuclides in aerosols, food products and construction materials; and disposal challenges or use of disposal methods that could result in unnecessary and high exposure to individuals and population via environmental pathways and media. Minerals such as monazite, ilmenite, zircon, phosphates, columbite, niobium and rare earth minerals among others contain high activity concentrations of uranium and thorium. Studies have shown that persons living near areas where mining and mineral activities of these minerals tend to be exposed to about 100 times more that the normal background radiations. This research therefore seeks to: characterize and quantify the radionuclide in media; evaluate effective dose; model the radiation dose through different exposure pathways and thereafter model radiological risk resulting from mining and mineral processing activities in Kwale County.