Concentrations of heavy metals in NPK fertilizers imported in Serbia

Abstract

Concentrations of Pb, Cd, Cu and Mn in sixteen NPK fertilizers imported and widely used in Serbia were determined by flame atomic absorption spectrometry (AAS). The results show that contents of heavy metals varied significantly in different fertilizers depending on N:P:K ratio and fertilizer origin. Pb and Cd contents in water solution of fertilizers occurred at low ranges: 2.0-3.1 and 0.03-1.56 mg/kg, respectively. An NPK (15:15:15) fertilizer from Romania was found to contain the highest concentration of Pb and Cd as impurities. Cu content, ranging from 7.1 to 974.7 mg/kg, was the highest in colored fertilizers from Hungary, the Netherlands and Greece. Mn value in a Hungarian NPK product (10:10:20) exceeds the average Mn value in soil. The data indicate variable contents of heavy metals in fertilizers, some of which are significantly higher than natural concentrations in soil, which suggests that they need to be continuously monitored.