Determination of Pesticide Residues in Selected Cereal Crops Grown in Selected Farms from Gbako

Abstract

The study was conducted to determine the residues of organophosphorus and synthetic pyrethroids in composite samples of maize,millet, guinea corn and rice from selected farms in Gbako, Niger State, Nigeria. Modified QuEChERS (Quick,Easy, Cheap, Effective, Rugged and Safe) method was used for the extraction of the pesticide residues from the samples. pesticide residues: atrazine, chlorpyrifos, cypermethrine, lambda-cyhalothrin and profenofos were detected by gas chromatography-mass spectroscopy (GC-MS) machine model SHIMADZU(GC 17A) from the extracted samples of maize, millet, guinea corn and rice. The detected pesticides were extracted from the cereals grain samples using acetonitrile, anhydrous magnesium sulphate, chloroform and sodium chloride. Cleanup of the extract was done with activated charcoal. The concentrations of 0.039 and 0.027 mg/kg were obtained for atrazine in maize and millet respectively, while (0.044, 0.010 and 0.029) mg/kg were recorded for chlorpyrifos in maize, millet and rice. The concentration of 0.019 mg/kg for profenofos was found in maize sample only. The values of 0.044 and 0.111 mg/kg were obtained for cypermethrin in maize and millet samples respectively, while for the maize and millet samples, the lambda-cyhalothrin contents were 0.034 and 0.036 mg/kg respectively. All these recorded results were compared with Codex maximum residue levels. It was found that all the values were below the maximum residue limit(MRLs), an indication that the values may not pose any health risk to the consumers at the moment. Although, the use of these chemicals especially cypermethrin and chlorpyrifos for a long period of time could pose some environmental and health challenges since they are not biodegradable. Hence their use is suggested to be discouraged in favour of their alternatives