DETERMINATION OF SELECTED HEAVY METALS (Cu, Pb, Zn, Cd, Cr, Ni and Fe) IN NON-LEAFY VEGETABLES SOLD IN MAJOR MARKETS IN AKURE, NIGERIA

Abstract

The present study was carried out to assess the concentration levels of seven heavy metals (Cu, Pb, Zn, Cd, Cr, Ni, Fe) in eight different non-leafy vegetables namely; Cyanne pepper (Capsicum frutescens), Bell pepper (Capsicum annum), Habanero pepper (Capsicum annum), Okro (Abelmuscusesculentum), Carrot (Daucuscarota), Cucumber (Cucumissativus), Garden-egg (Solanummelongena) and Sweet potato (Ipomoea batatas) collected from four different markets (Oja-oba, Shasha, Isikan and Odopetu) in Akure, Ondo State. Heavy metal concentration was determined using Atomic Absorption Spectrometer (AAS, VGP210). The results showed that in all the samples, the highest concentrations were observed for Cu (3.02 mg/100g) in Cyanne pepper at Oja-oba market, Pb (0.80 mg/100g) in Habanero pepper at Isikan market, Zn (7.53 mg/100g) in Okro at Oja-oba market, Cd (0.30 mg/100g) in Cyanne pepper and Bell pepper at Odopetu market, Cr (0.40 mg/100g) in Habanero pepper at Isikan market, Ni (2.70 mg/100g) in Carrot at Shasha market and Fe (32.20 mg/100g) in Cyanne pepper at Isikan, respectively. Also, the results showed that the mean concentrations of all the metals analyzed in the non-leafy vegetables were in the following order; Fe>Zn>Cu>Ni>Pb>Cr>Cd.It was observed that Pb, Cr and Cd levels exceeded the maximum permissible limits set by FAO/WHO, but the levels of Cu, Zn, Ni, and Fe were within the limits. Associated risk assessment of consumer’s exposure to heavy metals was assessed. However, the Daily Intake of Metal (DIM) and Health Risk Index (HRI) of these metals through consumption of vegetables from these market locations posed no risk to human health through the provisional tolerable daily intake (PTDI). The Hazard Index (HI) of all studied heavy metals further indicated that all the vegetables were safe with no risk to human health.However, proper monitoring plan and health risk assessment are necessary to evaluate the levels of metal concentration in vegetables in order to develop the proper measures for reducing excessive build-up of these metals in the food chain.