Determination of heavy metal (zinc, Zn, Iron, Fe and Lead, Pb) concentrations in some selected food crops (yam, cassava, and potato)

Abstract

The analysis of heavy metals (Zn, Fe and Pb) concentration of selected food crops namely yam, cassava and potato sourced from Aluu market a close agrarian community to Port Harcourt in Rivers State was carried out. Samples were powdered before digesting with aqua ragia solution. Various filtrate from the digested samples were sent for instrumental analysis for cations using atomic absorption spectrophotometer (AAS). The results showed that the concentrations of zinc (Zn) in yam, cassava and potato were 92.39, 69.42 and 11.04mg/kg respectively. The concentrations of iron (Fe) in the same crops sample were 24.78, 30.50 and 33.87mg/kg. Lead (Pb) concentrations in the same crops sample were 2.57, 3.26 and 1.83mg/kg respectively. The variations in the concentrations of the metals ions in crops samples may be attributed to the nature of the soil, the use of fertilizers and closeness of the farmlands to areas having high industrial activities. The high zinc and iron concentrations in yam and cassava show that these plants can serve as good sources of these metals. The potato with the highest iron concentration could also be a better source of iron than sweet potato and cassava. However, the high lead concentrations in cassava and yam, which are above the levels recommended by WHO /NAFDAC, mean that although they are good sources of iron and zinc, they can also be dangerous to humans if these plants, which come from the same source, are consumed continuously.