keywords: Cadmium, caffeine, Cola nitida, contaminants, farmers, pollutants
This study evaluated the residual pesticides and trace/toxic metal levels in a world-wide traded kolanut species, Cola nitida, using Gas Chromatography (GC) and Atomic Absorption Spectroscopy (AAS), respectively. Results indicated that all the kolanuts analysed in this study contained oximes, endosulfan, diazenon, diazepam, propoxur, chlordane, lindane, atropine, and alachlor in different concentrations. Kolanuts obtained from Oyingbo market had the highest loads of all the pesticides relative to the ones obtained from Mushin and Lagos Island markets. The pesticide that occurred in highest concentration in kolanuts across the markets was chlordane, followed by lindane and endosulfan. On the other hand, oxime, diazenon, and diazepam were present in relatively lower concentrations of between 0.02 mg/kg and 0.07 mg/kg of kolanut samples. Zinc, Cu, Pb, and Cd were present in all the kolanuts that were analysed. The highest mean Zn, Cu, Pb, and Cd concentrations of 5.14 ± 2.04, 4.46 ± 2.38, 0.52 ± 0.37, and 0.42 ± 0.29 mg/kg, respectively occurred in kolanuts obtained from Oyingbo market. The differences in pesticide and metal concentrations in kolanuts sampled from the three markets were not statistically significant (P > 0.05). Governments, regulatory bodies and agencies are called upon to institute collaborative programmes that would arrest the practice of preserving kolanuts with harmful pesticides.
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