Multi-pollutant dynamics in an industrial benthic ecosystem: Linking source apportionment, bioaccumulation, and...

Industrial benthic systems are major reservoirs of hydrophobic organic contaminants (HOCs) derived from industrial discharges, urban runoff, wastewater effluents, and maritime activities. This study quantified polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs), and alkylphenols (APs) in sediments and benthic crustaceans from Kaohsiung Harbor, Taiwan, and evaluated the factors controlling their distribution, bioaccumulation, and associated risks. Outside-harbor sediments exhibited ΣPAH, ΣPAE, and ΣAP concentrations ranging from 2.27 to 230, 25.4 to 340, and 1.40 to 72.8 ng g⁻¹ dw, respectively, whereas harbor sediments showed elevated concentrations of ΣPAHs (72.5-918 ng g⁻¹ dw), ΣPAEs (101-1406 ng g⁻¹ dw), and ΣAPs (34.5-603 ng g⁻¹ dw). PAHs were primarily controlled by total organic carbon (TOC), explaining up to 67% of the variance, while PAEs and APs were influenced by spatial variability and seasonal inputs. PAEs were enriched during the wet season due to runoff and wastewater transport, whereas APs accumulated during the dry season under reduced dilution and flushing conditions. Diagnostic ratios and Positive Matrix Factorization indicated predominantly pyrogenic PAH sources, with stronger wet-season petrogenic influence near harbor entrances and marine outfalls. Crustacean contaminant concentrations reflected sediment contamination patterns (PAEs > APs > PAHs), while compound-specific biota-sediment accumulation factor (BSAF) demonstrated that bioaccumulation was regulated by sediment bioavailability, contaminant partitioning, and species-specific exposure pathways. Risk assessments revealed episodic carcinogenic risks for PAHs, with incremental lifetime cancer risk (ILCR) values exceeding 10⁻⁵, whereas PAEs and APs posed persistent ecological risks. These findings highlight the importance of integrating source apportionment, bioaccumulation, and ecological risk assessment in harbor pollution management.