engleski

Radioactive contamination of soil close to phosphogypsum disposal pond

Natural radioactivity is a part of our natural surrounding and concentrations of natural radionuclides in the environment increase with the development of technologies. It has become clear that the rapidly growing world population must depend increasingly upon commercial fertilizers for its food and fiber. Phosphate materials used for production of phosphate fertilizers contain a minor quantity of radioactive material, mainly various members of the uranium and thorium series, and radiopotassium. In Republic of Croatia, the annual use of phosphate fertilizers is low. Specific activity of uranium is from 600 to 1400 Bqkg-1, of potassium about 3000 Bqkg-1. Thorium content is neglected. The basic phosphate material used to produce phosphate fertilizers unfortunately is very insoluble. For that reason, drastic chemical treatment with strong acid is necessary to produce soluble phosphate products. The result of classical process is precipitation of gypsum (termed phosphogypsum). The aim of the present work was to define the level of some natural radionuclides in soil samples collected from uncultivated surfaces close to phosphogypsum disposal pond at phosphate fertilizer plant in Republic of Croatia. The specific activities of uranium (238U) and thorium (232Th) decay series, as well as radiopotassium (40K) have been determined gammaspectrometrically.

radioactivity; phosphogypsum; soil; phosphate fertilizers

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