Distribution and Risk Assessment of Polychlorinated Biphenyls in Soil and Plants in Koko Town, Delta State, Nigeria

The distribution of Polychlorinated Biphenyls (PCBs) in Soils and Plants in Koko Town, Delta State, Nigeria, was studied using five soil samples and five edible plants collected from five industrial locations in the study area. Using Soxhlet apparatus and gas chromatography for the extraction of contaminants, and analysis, mean PCB concentrations were found to be significantly higher in plants (20.75mg/kg) than in soils (10.32mg/kg), exceeding the WHO safety thresholds. The sampled plants significantly accumulated PCBs in the following order; Pueraria phaseoloides  >  Ceiba pentandra  >  Chromolaena odorata > Vermonia amygdalina > Musa sapientum . Estimated daily intake of 0.000007mg/kg for adults and children and a hazard ratio of 1.0 as stipulated by USEPA, indicated substantial human health risks, especially among children. These findings underscore the ecological and toxicological urgency of controlling industrial PCB emissions in oil-producing regions.