Modeling multimedia fate and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the coastal regions of the Bohai and Yellow Seas

Abstract

Using an improved multimedia fate model, this study simulated the spatial distributions, partitioning behaviors, and mass exchanges of PAH16 (16 species with priority by the USEPA) in multiple environmental compartments in the coastal regions of the Bohai and Yellow Seas, Northern China. The model predictions generally matched well with the measured results, as the deviations of most points were within one order of magnitude in the air, freshwater, and 3 soil compartments. The estimated concentrations of ΣPAH16 in the northern part were higher than those in the southern part, which was consistent with the emissions of each part. Approximately 97.6% of the ΣPAH16 mass was distributed in soils; therefore, soils served as the dominant sink of PAH16. The estimated net flux of ΣPAH16 from air to soil ranged from 0.4 to 10.7 mg/m2/year (an average of 3.2 mg/m2/year), and the estimated flux of deposition from air to soil fell in the range of 0.4–10.8 mg/m2/year (an average of 3.2 mg/m2/year), which served as the dominant process at the air-soil interface. The estimated net flux of ΣPAH16 from air to freshwater ranged from −15.3 to 9.4 mg/m2/year (an average of −0.3 mg/m2/year), and the reversed volatilization flux from freshwater to air ranged from 0.01 to 21.1 mg/m2/year (an average of 3.7 mg/m2/year). This situation indicated notable spatial variations and volatilization as the main process affecting the direction of net flux at the air-freshwater interface. Deterministic risk assessment and probabilistic risk assessment were conducted. The overall health risks of the studied regions were acceptable, while the excess lifetime cancer risk (ELCR) by air inhalation was greater than that by soil ingestion. CapsuleMultimedia fate model-predicted distributions and compositions of PAH16 in different compartments, compartmental exchange fluxes and directions, and deterministic and probabilistic ELCR via different exposure pathways were assessed.