Assessment of Heavy Metal Contents, and Probable Health Risks of Some Staple Vegetables in Enugu Metropolis

Abstract

Heavy metals naturally are non-biodegradable constituents of the earth’s crust that accumulate and persist indefinitely in the ecosystem as a result of both human and natural activities. Their contamination of vegetables remains an issue of public health interest due to the frequency, and quantity of consumption. The over exposure to these heavy metals continues to pose serious health threat globally. This study was aimed to assess the heavy metal contents of staple vegetables [Telfairia occidentalis, Amaranthus hybridus and Ocimum gratissimum] within Enugu metropolis; the leaves were screened for heavy metals [Arsenic As, Lead Pb, Cadmium Cd, Nickel Ni, Chromium Cr and Cobalt Co], by atomic absorption spectroscopy (AAS). Results (Mean±SD,  mgkg-1 ) showed that Amaranthus hybridus: contained [Pb-0.109±0.350, Cr -0.161±0.004]; Ocimum gratissimum: [Ni-0.179±0.028, Cd-0.033±0.006, Cr-0.176±0.036], and Telfairia occidentalis: [Pb-0.153±0.139, Co-0.198±0.148]; of which some values were slightly above WHO/FAO standards. Although, the estimated daily intakes (EDIs) were below referenced tolerable daily intakes (TDIs). The hazard quotients (HQs) were below 1 (HQ<1), but As and Cd, were exceptions; while the hazard index (HI) values were all above 1 (HI>1). The slightly above standard references of some of these heavy metals, and HI>1 values in this study are a concern, as potential health risks may arise amidst the population over a period of time, therefore, there is need to eliminate the likely sources of the latent contamination.