Determination of Organophosphorus Pesticide Residues in Pepper and Soil from Edozhigi, Gbako LGA, Niger State

Abstract

This study was carried out to determine the concentration of organophosphorus pesticide residues in composite samples of scotch bonnet pepper and soil from Edozhigi, Gbako Local Government, Niger State. Modified QuEchERS method was used for the extraction. The concentrations of the pesticides were determined by gas chromatography-mass spectroscopy (GC-MS). The concentration of 0.060, 0.011, 0.004, 0.044, 0.022, 0.006, 0.255, 0.062, 0.096 mg/kg were obtained for Diazinon, Chlorpyrifos-Methyl, Pirimiphos – Methyl, Fenitrothion, Chlorpyrifos, Chlorfenvifos, Fenamiphos, Triazophos, and Azinfos - Methyl respectively. While for the soil the values obtained were 0.035, 0.046, 0.099, 0.016, 0.053, 0.061, 0.081 mg/kg for Dimethoate, Fenitrothion, Malathion, Chlorpyrifos, Ethion, Triazophos, Azinfos – Methyl respectively. The obtained values when compared with Codex Maximum Residue levels, were found to be below the Maximum Residue Limits (MRLs). The concentration of the detected pesticides in pepper were observed to be below the FAO/WHO maximum residue permissible limits of Diazinon (0.10 mg/kg), Chlorpyrifos-Methyl (0.30 mg/kg), Pirimiphos – Methyl (0.05 mg/kg), Fenitrothion (0.80 mg/kg), Chlorpyrifos (0.30 mg/kg), Chlorfenvifos (0.30 mg/kg), and Azinfos – Methyl (1.00mg/kg), except for Fenamiphos (0.03 mg/kg) and Triazophos (0.05 mg/kg), whose values are slightly above the stated permissible limits for the pesticides. Although, there is an indication that the pepper from the farms is safe for consumption and therefore may pause little or no health threat to humans but there is need for strict adherence to good agricultural practices (GAP), to avoid bioaccumulation and in the long run it’s negative effects on living things. However, periodic monitoring of the pesticide’s application and the determination of the chemical residue is recommended Key Words: organophosphorus, pepper, soil, transfer factor