Characteristics Of Polycyclic Aromatic Hydrocarbons In The Air-sea Interface In Xiamen Sea Areas

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants (POPs) which are known to be present worldwide in coastal waters. The levels and distributions of PAHs in the air-sea interface can affect the exchange direction and flux of vapor PAHs, and the biogeochemical behavior of PAHs in the marine environment.The surface microlayer and surface layer seawater samples from 13 sites around Xiamen Island were collected using stainless mesh and acryl glass sampler and analyzed for 16 priority PAHs, to characterize the spatial variations and partition between the dissolved and suspended particulate phases in the local marine environment. The results showed that PAHs concentrations in the dissolved fraction (61.97～341.87 ng/L) were much higher than those in suspended particulate phase (24.16～115.44 ng/L) for both microlayer and surface seawater samples. The PAHs concentrations in microlayer seawater in Xiamen Western Sea (151.58～341.87 ng/L and 41.69～115.44 ng/L for dissolved and particulate phase, respectively), due to the semi-enclosed water body and the sink of industrial and steamboat discharge, were much higher than those in the Eastern and South area (61.97～72.00 ng/L and 31.44～41.62 ng/L for dissolved and particulate phase, respectively). There was no dependency relation among the concentrations, partition of PAHs, tidal current, salinity, SPM and POC. The Marine Environmental Monitoring Station near Gulang Island was choosed to monitor the diurnal and seasonal variation of PAHs in the air-sea interface in summer and winter. PAHs concentrations in the dissolved fraction in summer were higher than those in winter due to the direct wet deposition and run-off due to the frequent precipitation in summer. The dissolved PAHs concentrations in the microlayer seawater in summer were higher than that in surface seawater while no significant difference was observed in winter. The diurnal variations of dissolved and particulate PAHs concentrations were influenced by the irritation, microbiologic reaction and atmospheric deposition. An intensive sampling program for PM10 aerosols was undertaken at Gulang Island during the water sampling time in both winter and summer. Significant differences of PAHs profile between the winter and summer samples and similar patterns in seawater and PM10 were found, indicating that a significant source of PAHs was from the sewage effluents and atmospheric deposition. The PAHs profile and diagnostic ratios showed that PAHs was from traffic-sources in winter. The solid-phase micro-extraction was used to analyze gas-phase PAHs, and only seven compounds of two- to four-ring were detected. The gas PAHs at night was much lower than that in the day due to the...