Nuclide, metal and non metal levels in percolated water from soils fertilized with phosphogypsum

Systematic generation of residues is more and more worrying in today.s world; adequate storage and reutilization are of great importance. Since generation of residues has become impossible to avoid, the possibility of reuse must be studied and researched. An example of these residues is phosphogypsum, which is generated in phosphoric acid production at the rate of around 4.8 tons for each ton of phosphoric acid produced. Many studies seek to reuse phosphogypsum in agriculture as a source of calcium and sulfur, potassium or aluminum, especially in soils from Brazil's cerrado regions. Though phosphogypsum is mainly composed of dehydrated calcium sulfate, it can have high levels of heavy metals, non metals (As and Se), fluorides and natural radionuclides. Thus, its uncontrolled use as a soil conditioner can lead to contamination of underground water. (author)