ABSTRACT

1-leavy metal pollution of agricultural soils and commonly consumed food crops: Orange (Citrus sinensis), Pawpaw (Carica papaya), Star apple (Chrysophyllum albidum), Fluted pumpkin (Telferia occidentalis), Waterleaf (Talinum triangulare), Bitterleaf ( Vernonia amygdalina), Coconut (Coco snucifera), Palm nut (Elaies guineensis), Kolanut (Cola acuminate), is one of the most severe ecological problems on a world scale. This study evaluated the potential carcinogenic and non- carcinogenic health risk to populace residing around the industrial local of Ezekwabor in Nnewi, Anambra State. Iron (Fe) was the most bio-accumulated heavy metal in virtually all analyzed samples. Mean Cu levels were below W.H.O detection limit. Across samples and locations heavy metal concentration in food crops was in the decreasing order Fe>Mn> Cu> Zn>Pb>Cd.  Mean Fe, Mn, Zn, Pb and to reasonable extent Cd levels in all samples were above the permissible limits set by international regulatory bodies. Comparatively, the combined concentration of heavy metals in food crops from Nnewi was in the range 32831.05mg/kg dry weight (dw), 997.26 mg/kgdw, 415.91 mg/kgdw, 222.35 mg/kgdw, 149.31 mg/kgdw, 2.64 mg/kgdw for Fe, Mn, Cu, Pb, Zn and Cd. While the concentration of heavy metals in samples from the commercial and residential area of Umudike was found to be 4,470.5 mg/kg, 845.4 mg/kgdw, 110.3 mg/kgdw, 7.10 mg/kgdw and 0.3 mg/kg dw for Fe, Mn, Cu, Zn, Pb, and Cd. Mean copper levels in control samples were below WHO detection limit of 0.0001 mg/kg. Results showed that people living in Nnewi and Umudike are ingesting high doses of Mn beyond the reference oral dose. THQ values obtained in this study were> 1 indicating potential health risk to the residents of Nnewi due to Pb and Fe intoxication. Cd, Zn and Cu gave THQ values <1 indicating no health risk due to their intake by the human populations understudy. Residents in the studied areas are exposed to carcinogenic risk due to Cd and Pb exposure with greater concern for Nnewi. Instances where Daily intake, THQ and CR values for which Umudike and Nnewi indicated health risk Nnewi showed greater levels of concern.