Characterization and phytoavailability evaluation of micronutrients and contaminants in some Brazilian phosphate fertilizers

Brazilian fertilizer legislation considers the total concentration of micronutrients as being the guarantee of their presence in fertilizers. This fact allows the use industrial by-products as micronutrient source for fertilizers, which brings the risk of the presence of high amounts of toxic elements that may lead to soil contamination. The purpose of this study was to determine the micronutrient and contaminant contents in six Brazilian commercial phosphate fertilizers and to evaluate the phytoavailability of elements from soils treated with these fertilizers. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine the contents of the elements. As, Cd, Co, Cr, Fe, Mo, Na, Sb and Zn were detected in fertlizers. Concentrations in vegetal tissue were not modified by the treatments, except for Cd, which was increased due to fertilizers application.