Blood and Urinary Levels of Polychlorinated Biphenyls in Occupationally Exposed Population in Akure City, Nigeria

Despite the age-long ban on the production of polychlorinated biphenyls (PCBs), exposure to humans continues because of the persistent nature of the chemical. This study is a baseline assessment of the exposure level of the blood and urine of auto-mechanics to PCB congeners in Akure metropolis, Nigeria. Exposure assessment was based on total PCBs in blood and urine of smoking and non-smoking auto-mechanics. PCB congeners were analyzed by high-resolution gas chromatography coupled with an electron capture detector (GC-ECD). Total PCB concentrations in blood and urine, computed as the sum of the 19 congeners ranged from 0.365 to 7.534 µg/L and 0.069 to 1.099 µg/L, respectively. The study showed no correlation between PCB concentrations in blood and urine. The study observed a significantly lower sum of non-dioxin-like PCBs (PCB-28, 52, 101, 118, 138, 153, and 180) in urine (0.021–0.267 µg/L) than those in blood (0.056–3.001 µg/L). On average, the dioxin-like PCBs constituted over 20% and 25% of the total PCBs in blood and urine, respectively. Six low-chlorinated PCB congeners (1, 31, 52, 66, 77, and 118) constituted on average 81% and 41% of the total average PCBs in blood and urine samples, respectively. Thus, they could serve as indicator PCBs in the blood and urine samples of artisans. Comparatively, the study recorded greater contributions of different dioxin-like PCBs to the total toxic equivalent quantity (TEQ) in smoking than in non-smoking auto-mechanics. Our findings showed PCBs and dioxin-like activity as potential biomarkers in the blood and urine samples of artisans. The study also suggests potential exposure to PCBs via occupational and domestic engagements.