Determination of some herbicides in foreign and local rice brands obtained from Makurdi, Benue, Nigeria

Abstract

Rice consumption has increased worldwide over recent decades, as it has become one of the most common foods. However, there is dearth of information regarding the analysis of pesticide residues in rice-grain. Thus, residues of some pesticides were determined in selected rice brands sold in three markets in Makurdi metropolis Benue State - Nigeria using gas chromatograpy mass spectrometry. Prior to the GC-MS technique analysis, Quick Easy Cheap Effective Rugged Safe (QuEChERS) method for extraction and clean-up was carried out. The results showed pesticides with most occurrences as; Dichloran, Heptachlor epoxide, Propyzamide, Chlorpyrifos, Diazinon, Endosulfan II, Methoxychlor and Mirex; followed by BHC, Aldrin, Trifluralin, Dieldrin, Endrin P, p – DDT, and Antrazine. Whereas, 2, 4 – D, Propanil, BHC and Trifluralin were not detected across all the samples. Occurrences of the residues in the rice samples were influenced more by pesticide type rather than rice brand. All cases of the detected pesticide residues were found to exceed the Maximum Residue Limits (MRLs) set by the European Union with Mirex having the highest concentration of 6.9255 mg/kg (which is 1385 times the MRLs) and heptachlor with the least concentration of 1.5831 mg/kg (which is like 158 times the MRLs).