More still needs to be learned regards the relative contamination of heavy metals and pesticide residues, particularly those found in widely consumed Nigerian food crops like cereals, vegetables, and tubers. In this current study, the heavy metals and pesticide residues detectable in widely consumed Nigerian food crops were respectively quantified using atomic absorption spectroscopy (AAS) and gas chromatography (GC). Specifically, the widely consumed Nigerian food crops included cereals (rice, millet, and maize), legume (soybean), tubers (yam and cassava), as well as leaf (fluted pumpkin, Amaranthus leaf, waterleaf, and scent leaf) and fruit vegetables (okro, cucumber, carrot, and watermelon). Results showed that the detected heavy metals included arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), and nickel (Ni), whereas the pesticide residues included Aldrin, Carbofuran, g-chlordane, Chlorpyrifos, DichloroBiphenyl, Dichlorodiphenyldichloroethane (DDD), Dichlorodiphenyltrichloroethane (DDT), Dichlorvos, Endosulfan, Heptachlor, Hexachlorobenzene (HCB), Isopropylamine, Lindane, t-nonachlor, and Profenofos. Across the studied food crops, the concentrations of heavy metals and pesticides were varied, with different trends as they largely fell below the established maximum permissible limits, and with some exceptions. Our findings suggest there could be a somewhat gradual decline in the concentration of the heavy metals and pesticide residues of these studied food crops when compared to previously published reports specific to Nigeria. To help substantiate this observation and supplement existing information, further investigations are required into the concentration of these heavy metals and pesticide residues specific to these studied food crops at other parts of the country.
Keywords: cereals; chemical toxic contaminants; consumer food safety; maximum permissible limits; tubers; vegetables.