Speciation of Metals and Risk Assessment in Selected Food Crop Samples Grown in Ohaji/Egbema LGA, Imo State, Nigeria

Abstract

Ohaji Egbema is known for its oil production and exploration activities and so crops grown in this area could be contaminated. Chemical speciation was carried out on four commonly grown food crops in the area so as to determine the level of metal contamination. The samples were analyzed sequentially and the metal species in the extract determined by ASS. Results revealed that mean concentrations of all studied metals to fall within the WHO/FAO permissible limits. Significant bioavailability was observed for Pb in Okoro (0.67) and Orange (0.7). Zn showed the highest concentration and its bioavailability was highest for Okoro (12.6)>Pawpaw (7.9)>Orange (5.5)>Cassava (0.28). The sum of EDI for both adult and children exhibited similar trend with Cassava having the least value in both adult and children. Though metals showed low values of EDI, excessive consumption can have adverse effect in humans due to bioaccumulation in living system. Hazard Quotient (HQ) was highest for Pb (3.524) in Pawpaw for children while Fe (0.705) was highest in Pawpaw for adult. Generally, HQ was found to be highest in children for all the metals indicating great health risk for children. Risk associated with consuming these four fruit crops in terms of summation of RAC revealed the order of decrease to be: Okoro (1620)>Pawpaw (1021)>Orange (861)>Cassava (178). This study has shown that the consumption of these fruit crops could be a great health risk for children.