Concentrations of Pesticides Residues in Grain Sold at Selected Markets of Southwest Nigeria

Abstract

The objective of this work is to determine the concentration of the identified pesticide in grains commonly used by farmers, and which are available directly from the open markets in the Nigerian market. Pesticide residues were quantified through a multiresidue method using a varian 3800/4000 Gas Chromatograph Mass Spectrometer (GC/MS). The simultaneous measurement of four classes of pesticides by gas chromatography-mass spectrometry (GC/MS) approach using sample preparation on QuEChERS-citrate, was developed and validated. The results frequently showed high specific contamination, which makes sense given the target market and dietary diversity in the area. This study found that grains purchased from particular markets in southwest Nigeria contained numerous pesticide residues. The MRLs set by the EU or FAO/WHO or both were surpassed by 17 out of the total 27 pesticides reported in this work in at least one grain, despite the fact that there were no published codex MRLs for some pesticide residues in some grains. These residues were classified among the four pesticides classes: carbamates, organophosphates, organochlorines, and pyrethroids. In actuality, 90% of the mainly banned organochlorine pesticides exceeded MRLs. Thus, this study revealed higher concentration levels of organo-chloride pesticides and organo-phosphate pesticides in grain samples drawn from selected markets in southwest Nigeria. Consumers seeking high-quality food in Nigeria should take note of these facts.