Determination of Uranium in Environmental Samples
Uranium is a naturally occurring element that is abundant in soil, plants, freshwater, and seawater and can also be found in various biota samples. Its concentration in soil and plants varies widely between geographical locations according to the composition of the minerals in the environment and in natural water sources. In addition to natural sources, incidental releases of uranium that originate from anthropogenic activities, mainly those involving the uranium nuclear fuel cycle, affect its abundance in the environment. The International Atomic Energy Agency (IAEA) has published a number of technical reports in which many facets of the behavior of uranium in the environment, particularly transfer factors between environmental media, were described and discussed (TECDOC-1616 2009; IAEA 2010). Anthropogenic activities that may cause discharge of uranium compounds include uranium mining (as well as secondary uranium deposits such as phosphate and gold mines), uranium conversion facilities and isotope enrichment plants, nuclear fuel fabrication, nuclear power plants, reprocessing facilities, and nuclear waste treatment processes and their repositories. A schematic presentation, from the inaugural lecture delivered by Dr. Frank Winde in South Africa, is shown in Figure 3.1 (Winde 2013). The release of uranium from natural and anthropogenic sources into the environment is followed by its transport through air, water, and soil that could lead to human exposure through the food chain, drinking water, and inhalation from air.