A Landscape View into Legacy Polychlorinated Biphenyls (PCBs) Occurrence, Spatial Distribution, and Health Risk Assessment in Environmental Components of Shueib and Kafrein Dams

This study provides the first comprehensive assessment of dioxin-like polychlorinated biphenyls (DL-PCBs) contamination in the Shueib and Kafrein dams within the Jordan Valley catchment, aiming to support the sustainable management of Jordan’s limited water resources. Twelve PCB congeners were quantified in sediments, water, and vegetation using gas chromatography with electroncapture detection (GC-ECD), with compound identities verified by GC-EI/MS. Across both dams, total PCBs concentrations followed the order sediments > vegetation > water. Sediments showed the highest accumulation, with Shueib Dam registering a total average concentration of 5.23 ± 1.11 ng/g (d.w.), notably higher than Kafrein Dam’s 2.21 ± 0.46 ng/g (d.w.). PCB-77, PCB-114, and PCB-118 were the dominant congeners in sediments, while PCB-77 and PCB-118 were most prevalent in water samples, which recorded total average concentrations of 13.59 ± 2.30 ng/L in Shueib and 14.94 ± 2.67 ng/L in Kafrein. PCBs levels in sediments correlated positively with organic matter content and, in water, with pH. Spatial analysis revealed increasing PCBs concentrations toward upstream areas of Kafrein Dam, whereas Shueib Dam showed peak contamination in its midsection. Principle component analysis (PCA) indicated that sediments are dominated with penta-PCBs, hexa-PCBs, and hepta-PCBs but enriched with tetra-PCBs (PCB-77). Health risk assessment identified significant non-carcinogenic risks (ingestion as primary exposure route) particularly for children (Hazard Index 1.89–26.8), alongside potential carcinogenic risks for few locations. PCB contamination also poses ecological threats, including impacts on wildlife and bird reproduction. As the first detailed evaluation of PCBs’ distribution in these dams, this study establishes critical baseline data and underscores the need for targeted monitoring, strengthened regulatory measures, and sediment remediation to protect public health and ensure long-term water security in Jordan.