Determination of Polychlorinated Biphenyls Levels and Associated Risks in Soil-Derived Atmospheric Dust at a Mining Site in Oyo State, Nigeria

Abstract This study focused on polychlorinated biphenyls (PCBs), a group of persistent toxic compounds with significant environmental and health risks, particularly in mining-impacted regions. PCB contamination was investigated at a mining site in Ibadan, Nigeria, by analyzing the distribution, concentrations and interrelationships of 18 PCB congeners. The mean total PCB concentration across all samples was 186.42 ng g −1 , ranging from 42.35 ng g −1 at site G3 to 451.27 ng g −1 at site G1, indicating severe contamination hotspots. Correlation analysis showed strong positive relationships, such as PCB161 vs PCB183 (r = 0.87, p < 0.01) and PCB99 vs PCB206 (r = 0.94, p < 0.01), suggesting common anthropogenic sources, likely linked to historical mining activities. In contrast, significant negative correlations, such as PCB5 vs PCB99 (r = − 0.71, p < 0.05), implied distinct environmental degradation pathways. Communalities analysis revealed that most congeners had variance explanations above 70%, with PCB180 (82%) and PCB138 (79%) being highly influenced by shared factors, while PCB161 (42%) and PCB168 (39%) were affected by unique sources. Human health risk assessments indicated that ingestion contributed the highest incremental lifetime cancer risk (ILCR). For example, at site G1, ingestion ILCR was 2.12 × 10 −5 , compared to 1.40 × 10 −5 for dermal exposure and 1.21 × 10 −6 for inhalation. These results highlight the urgent need for targeted remediation strategies, especially in hotspots like G1 and G2, and demonstrate the importance of understanding both shared and unique contamination pathways when managing PCB pollution in mining environments. Graphical Abstract