Trace Elements in Commercially Available Triple Super Phosphate Fertilizers in Sri Lanka

Abstract

This study tested the trace elements in commonly used Triple Super Phosphate (TSP) fertilizers in Sri Lanka. TSP samples collected from two Fertilizer Companies (A and B) were used. Six replicates of each company fertilizers were digested following the method of the Association of Official Agricultural Chemists. The concentration of eleven trace elements (Cr, Mn, Cu, Cd, Pb, Zn, Fe, Ni, Co, Mo and As) in each TSP fertilizers were determined by ICP-OES as an analytical technique. ICP-OES analysis revealed a group of non-lethal metal species, present as impurities. The highest average concentrations were, 4229.30 mg of Fe, 469.16 mg of Mn, 195.34 mg of Zn, 8.73 mg of Ni, 7.78 mg of Cu, 2.36 mg of Co and 1.39 mg of Mo per kg-1 of fertilizer. Considerable amount of hazardous elements such as Pb, Cr, As and Cd were detected with average concentrations of 53.93 mg of Pb, 25.56 mg of Cr, 3.19 mg of As, 1.05 mg of Cd per kg -1 of fertilizer, respectively. Trace metal concentrations of samples collected from two fertilizer companies were compared using two sample t–test (α = 0.05). It was observed that, Mn, Cu and Zn were significantly higher in company A fertilizer samples than those of the company B. Concentrations of Cr, Cd, Pb, Fe, Co and Mo were significantly lower in company A fertilizer samples compared to samples of company B. However, there was no significant difference in concentrations of Ni and As contents in fertilizer samples of company A and company B. This study suggests the future course of action for the quality of the TSP fertilizer imported and the protocol or an act to regulate the standard limits of metal impurities present in TSP fertilizers imported to Sri Lanka.