Four commonly consumed leafy vegetables, obtained from four major cities in southern Nigeria, were analysed for their polycyclic hydrocarbon (PAH) content using gas chromatography coupled with mass spectrometry (GC-MS). The estimated daily intake (EDI), margin of exposure (MOE), hazard index (HI) and total cancer risk (TCR); principal component analysis (PCA) and diagnostic ratios (DRs) were respectively used for risk evaluation and source identification of the detected PAHs. The results showed that the mean concentration (µg kg-1) of ∑16 PAHs in the vegetables ranged from 532 to 2261. The EDI values ranged from 459 to 4876, 1809 to 8378, 2733 to 13,036 and 4143 to 12,568 ng kg-1 bw day-1 for benzo[a]pyrene (BaP), PAH2, PAH4, and PAH8 for children exposure respectively, and from 115 to 1219, 452 to 2095, 683 to 3259 and 1036 to 3142 ng kg-1 bw day-1 for adult exposure respectively. The estimated MOE values were < 10,000, indicating that the vegetables were unsuitable for consumption. The HI values were < 1, suggesting that there were no potential non-carcinogenic risks, but the total cancer risk values (> 1 × 10-6) designated carcinogenic risk of PAHs with consumption of these vegetables. The DR and PCA result showed that PAHs originated from high-temperature pyrogenic processes and vehicular emissions.
Keywords: Daily intake; Hazard index; Margin of exposure; PAHs; Total cancer risk.