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. The research was carried out at Kwara State University (Kwara State) and Afe Babalola University (Ekiti State) research laboratory. A total of twenty-four (24) samples were collected in the frame of this preliminary study within the month of August and September 2021. 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 was 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. Notwithstanding, the small number of samples with detectable residues suggests that there is a necessity to increase monitoring of pesticides in grains, educating farmers, and raising their awareness of the dangers associated with the unauthorized use of pesticides that are only allowed in agriculture and can damage the reputation of the sector as a whole. In order to check and restrict its unauthorized importation, sale, and use, the National Agency for Food and Drug Administration and restrict (NAFDAC), nongovernmental organizations (NGOs), and other pertinent entities must boost surveillance.