"Behavior of radionuclides in uranium series and associated trace elements for some phosphate rocks"

Abstract

Studies of natural environmental radiation and radioactivity are of great importance and interest for the environment as well as many other disciplines. Environmental radiation originates from a number of naturally occurring and human-made sources .The estimation of exposure to ionizing radiation is an important goal of regulatory authorities and radiation protection scientists. Thus knowledge of the background radiation level is of paramount importance (Drek et al., 2010).The distribution of radionuclides varies from area to another due to many reasons like the geological localities and natural chemical reactions as well as man activities. Study of natural radioactivity is usually done in order to gain information about the present levels of harmful pollutants discharged to the environment itself or in the living creatures. Phosphate ores of sedimentary origin have higher concentrations of radionuclides of the uranium family, the uranium concentration in the sampling region is more dependent upon the climatic effects, seasonal variability and the effects of evapotranspiration. Phosphate ores are present in the chemical form of calcium phosphates Ca3(PO4)2 which are very old marine deposits associated with fossils. This form represents 85% of the worldwide production. The second type of phosphate materials is apatite that is igneous origin (El- Bahiet et al ., 2017). Phosphates are used extensively, as a source of phosphorous for fertilizers and for manufacturing phosphoric acid and gypsum. The use of phosphate fertilizers in agriculture and of gypsum in building materials is a further source of possible exposure to the public (Gaafar et al ., 2016 ). Elevated radon exposure to the public can further be expected in sites being developed for housing (Vandenhove, 2000). The relative activities or abundance of a parent and daughter radioactive nuclei provide basic information about the type of equilibria and enrichment/ depletion processes like the measured ratios of 234U/238U, 226Ra/238U, 230Th/238U, 230Th/234U and 226Ra/230Th. The phosphate deposits in Egypt are exposed in three major areas named: the Western Desert, the Nile Valley and along the Red Sea between Safaga and Quesir. These deposits yield ore containing 90% phosphate and from 25 to 100 ppm uranium. Lesser importance are phosphate deposits in the Sinai Peninsula, which are of