Dietary risk assessment of organophosphate and carbamate pesticide residues in commonly eaten food crops.

Abstract

This study seeks to quantify and assess the risk associated with the level of organophosphate and carbamate pesticide residue in many foods commonly grown and consumed in Nigeria. Cereals, pulses, vegetables and fruits were sampled from two major markets in Lagos, Nigeria. The pesticide residue were extracted and analyzed for organophosphate and carbamate pesticide residues on a Gas Chromatograph (Agilent 7890A) hyphenated to a Mass Spectrometer (GC–MS). The concentration of dichlorvos in the cereals and pulses were all below the limit of quantification (LOQ) of 0.26 ng/g while the concentration in sorghum and beans was found to be 2.00 ng/g in both food crops. The concentration of mocap in vegetables and fruits varied from <0.16 to 20 ng/g. Chlorpyrifos concentration in fruits and vegetables varied between <0.50 and 30 ng/g. The concentration range of tokuthion and guthion were <0.15 to 10 ng/g and 0.002 to 60 ng/g in vegetable and fruits respectively. Methiocarb and 3-hydroxylcarbofuran were present in all the vegetables and fruits at concentration of 1 to 30 ng/g and 2 to70 ng/g respectively. Of all the organophosphate pesticide residues analyzed in this study guthion had the highest concentration consistently while of the carbamates, 3‑hydroxyl carbofuran had the highest mean concentration values for vegetables and fruits. Generally, vegetables had more organophosphate pesticide residue followed by cereals and fruits. Grains had the least amount of pesticides residue in this study. The largest amount of carbamate pesticide residue was also associated with vegetables followed by fruits. Cereals and pulses had the lowest amount of carbamates pesticide residue. None of the organophophate and carbamate pesticide residue detected were above the maximum residue limits (MRLs). Dietary risk assessment of organophosphate pesticide residues in selected foods did not indicate any health threat. Continuous monitoring and control of pesticide residues in food commodities should still be carried out to sustain the level of compliance.