Analysis and human health evaluation of trace metals and polycyclic aromatic hydrocarbons in Ocimum basilicum and Vernonia amygdalina cultivated close to industrial markets in Owerri, Imo State

This study evaluated the presence of polycyclic aromatic hydrocarbons (PAHs) and trace metals in Vernonia amygdalina and Ocimum basilicum leaves grown near Ekeonunwa, Relief, and Toronto industrial markets in Owerri. High-performance liquid chromatography (HPLC) and Inductively Coupled Plasma Optical Emission Spectrophotometry (ICP-OES) were employed for analysis, with Cold Vapour Atomic Fluorescence Spectrophotometry (CV-AFS) specifically for mercury detection. PAH Concentrations (mg kg−1 PAHs): V. amygdalina: Ekeonunwa (5.56), Relief (8.99), Toronto (0.13) O. basilicum: Ekeonunwa (7.18), Relief (3.37), Toronto (0.17), while The average levels of metals in the soil samples ranked in descending order as follows: Fe > Mn > Zn > Cu > Al > Cd > Pb > Cr > Co > V > Li > Hg, while those in the vegetable samples followed the sequence: Fe > Mn > Zn > Cu > Al > Pb > Cd > Cr > V > Co > Li > Hg. Average metal concentrations were higher than FAO/WHO maximum permissible limits. Estimated Daily Intake (EDI) values for all metals were lower than their respective Reference Doses (RfD), Health Risk Index (HRI), Target Hazard Quotient (THQ), and Hazard Index (HI) values for both vegetables were significantly below 1, suggesting minimal risk from metal exposure. However, Target Cancer Risk (TCR) and Cumulative Target Cancer Risk (CTCR) assessments indicated a potential elevated cancer risk for individuals consuming these vegetables from areas where risk thresholds were surpassed. Preventative measures are recommended in these specific locations.