Assessment of heavy metals concentration and health hazard indices in soil and plants from Kokona Local Government Area of Nasarawa State, Nigeria

Human dependence, on the plants grown on soil and the threat posed by contaminated soil to the ecosystem and general public has become a source of concern. The health risks caused by heavy metals concentration to the study area were evaluated. Fifteen (15) plant samples and soil samples each from the study area were collected and analyzed using an Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) for Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Copper (Cu), and Zinc (Zn). The Measured concentrations of these heavy metals were in the order of Cd>Ni>Cu>Zn>Pb>Cr for the plant samples and Cr>Cd>Ni>Cu>Pb for soil samples with Cd and Cr as the highest contributors to cancer risk in term of the carcinogenic risk estimate. The Health Hazard Index value for all pathways were found to be 7.34 x 10-1 making non-carcinogenic risk component less significant to the adult population and in case of children, the Hazard Index value was 1.21, a value greater than unity (1), which present a severe non-carcinogenic risk component to children living in the study area. The carcinogenic risk was found to be 8.68 x 10-6 implying that 1 person in every 5882 adults may be affected and 1 in 2725 children may be affected (9.6 x 10-5) These carcinogenic risk values were both higher than acceptable values.