Levels of Heavy Metals and Their Risk Assessment in Kolanuts (Cola nitida Schott & Amp; Endl.) Collected from Cote d’Ivoire, West Africa

Abstract

Background: Kolanut represents a significant economic interest for this country as well as many African households and public authorities. Despite its obvious importance, the sector of the kolanut is facing a delicate sanitary quality of the marketed product. The majority of the production (90%) of kola is consumed daily fresh by people and could cause a serious health problem for consumers if the toxicity due to heavy metals were proven. Aims: This study aimed to determine the heavy metals levels in kolanuts and estimate the risks of nuts consumption on population health in Côte d'Ivoire. Study Design: Samples were collected from farmers, rural collectors, urban stores in districts (Mountains, Comoe, Lagoons, Down-Sassandra) and big storage centers of Anyama and Bouake. Methodology: Concentrations of 3 heavy metals were measured using Atomic Absorption Spectrophotometry. The analysis of lead and cadmium was performed in flame mode (Air / nitrogen), with an AAS type VARIAN SPECTRAA 110 provided the furnace GTA 110. While, the analysis of mercury was carried out in hydride mode with a SAA system equipped with a vaporization unit (VGA 77). Results: Results showed the presence of the 3 heavy metals in kolanuts samples, with concentrations ranging from 5.37 μg/kg to 11.21 μg/kg, 17.49 μg/kg to 51.01 μg/kg and 19.99 μg/kg to 40.35 μg/kg for lead, cadmium and mercury, respectively. Based on the concentrations and the daily consumption of kolanuts estimated at 0.6 g/person in Côte d'Ivoire, the intakes values estimated by heavy metals were 4.8.10-3 ± 4.9.10-4 µg/j, 1.3.10-2 ± 9.07.10-4 µg/j and 1.7.10-2 ± 1.99.10-3 µg/j for lead, cadmium and mercury, respectively. The exposure daily doses (EDD) are all lower than the toxicological reference values. Thus, the occurrence of a toxic effect from Pb (HQ = 1.94.10 -5 <1), Cd (HQ = 1.9.10 -4 <1) and Hg (HQ = 3.4.10 -4 < 1) after Kolanuts consumption is very unlikely since the HQ are all less than 1. Conclusion: Consumption of kolanuts from Côte d’Ivoire would not present any health risk for the consumer.