Source apportionment and fate simulation of polycyclic aromatic hydrocarbons (PAHs) in typical coastal port sediments: combining PMF-based and fugacity-based fate models

Introduction Coastal ports are typical hotspots for polycyclic aromatic hydrocarbons (PAHs) accumulation. The complex pollution sources and constrained hydrodynamic conditions present significant challenges to the quantitative source tracing and fate simulation of PAHs. Methods This study used Qingdao Port (Jiaozhou Bay) as the research object, collecting 24 surface sediment samples. A positive matrix factorization (PMF) model was used to identify and quantify four main pollution sources. Using the emission rates of each source as input parameters, a Level III steady-state non-equilibrium fugacity model was constructed to simulate the migration flux and steady-state distribution of Σ16PAHs in four media: atmosphere, seawater, sediment, and biota. Results The results showed that the average concentration of Σ16PAHs in the studied port was 178 ± 94 ng/g dw, with the highest average concentration at the bulk cargo terminal (256 ± 84 ng/g dw), placing it at a moderate pollution level compared to other ports globally. PMF analysis identified four sources: coal/biomass combustion (35.2%), ship exhaust (28.5%), oil/fuel spills (21.8%), and road traffic (14.5%). The bootstrap confidence intervals for each factor were within ±5%. Fugacity model validation returned a coefficient of determination R 2 = 0.92 and a Nash–Sutcliffe efficiency NSE = 0.86 on log-transformed simulated–measured pairs, with sediment constituting the primary sink for PAHs in the port and accounting for an estimated 72%–85% of the total mass. Normalized sensitivity coefficient (NSC) analysis revealed that log K ow (NSC = +1.85) and Henry’s law constant H (NSC = −1.52) were the most critical parameters affecting the concentration of PAHs in sediment. Σ16PAH concentrations exceeded the CCME ISQG benchmark (100 ng/g dw) at all bulk cargo terminal stations and at 75% of container terminal stations, indicating elevated ecological risk within these functional zones. The lifetime intradermal carcinogenic risk (ILCR) for adults via dermal contact was below the acceptable level of 10 –4 at most stations. Conclusions The “source-fate-risk” integrated framework constructed in this study provides methodological support for the refined management of PAHs in port sediments.