POLLUTION OF FERTILIZERS WITH HEAVY METALS

The aim of presented investigations was a comparison of heavy metal content in mineral fertilizers used in Poland and determining the sources of their origin in the fertilizers. The methods assumed as referential in fertilizer analysis were used to assess the contents of Cd, Cr, Cu, Hg, Ni, Pb and Zn in 44 samples of mineral fertilizers, including 29 fertilizers containing phosphorus (2 superphosphates and 27 multicomponent fertilizers), 14 nitrogen fertilizers and 1 potassium salt. Considerable amounts of heavy metals were determined only in phosphorous and multicomponent fertilizers. A small content of lead was assessed in nitrogen fertilizers and in potassium salt, whereas usually only trace amounts of the other metals were detected. In the group of phosphorus and multicomponent fertilizers zinc, chromium and nickel occur in the biggest quantities, whereas mercury and lead in the smallest ones. The potential main source of cadmium, chromium and zinc in fertilizers containing phosphorus is phosphorite raw material while the source of nickel in multicomponent fertilizers is admixtures of ground dolomite. The permissible content of cadmium (50 mg.kg(-1)), lead (140 mg.kg(-1)), or mercury (2 mg.kg(-1)) were exceeded in none of the analyzed fertilizers or mineral fertilizers not used for liming.