Natural environmental radioactivity arises mainly from natural radionuclides, such as 40K and the nuclides from the 238U and 235U series and their decay products which occur at trace levels in all ground formations due to their origins. The fission product 137Cs is strongly adsorbed and retained by the soil particles, like the natural radionuclides which are found randomly distributed at different depths of soil. The subject of radioactive contamination has gained considerable public importance because of the Chernobyl accident. Over the last few the uses of phosphate fertilizers have been...