Characterization Of Selected Inorganic Fertilizers By Atomic Absorption Spectroscopy: Possible Carryover Of Heavy Metals From Phosphate Rock

Fertilizers are important in increasing and sustaining soil fertility resulting in increased productivity and hunger reduction. The excessive use of inorganic fertilizers on croplands may contaminate the soil with heavy metals and naturally occurring radioactive materials. Seven elements (Cd, Cu, Fe, Ni, Mn, Pb, and Zn) in six randomly selected Nitrogen- Phosphorous- Potassium fertilizers, two Single Super Phosphate and one Diammonium Phosphate fertilizers purchased from Zaria, Kaduna State, Nigeria and two Phosphate rock samples obtained from Institute for Agricultural Research , Ahmadu Bello University, Zaria were characterized using Atomic Absorption Spectroscopic technique. The results showed that, the highest concentration of Cd 15.9mg/kg recorded by DAP fertilizer sample was lower than in Sokoto and Togo Phosphate rock samples but was higher than the concentration in agricultural soils.. The concentration of Copper in Sambuka four corner vital NPK (15-15-15) and DAP was 13.0 mg/kg and 32.0 mg/kg respectively these were higher than the copper concentration in Sokoto rock phosphate sample, 11.2mg/kg. The NPK fertilizers have a range of Fe concentrations 12,63mg/kg-99.24mg/kg which is lower than the concentration in Sokoto rock phosphate sample160,28mg/kg.The fertilizers(crp6,crp8and crp9) have Fe concentration one and half times higher than Togo rock phosphate sample. However, CRP4, CRP5 and CRP6 of the NPK fertilizer samples had Fe concentration three times higher than Togo Phosphate rock. Diammonium phosphate fertilizer has the highest concentrations 3900mg/kg of Zinc. The average concentration of the seven elements analyzed was within the ranges in agricultural soils. The samples showed appreciable concentration of Mn, and Zn which are beneficial to plant growth.of lead is insignificant.