Fossil Fuel-Derived Polycyclic Aromatic Hydrocarbons in the Taiwan Strait, China, and Fluxes across the Air-Water Interface

On the basis of the application of compound specific radiocarbon analysis (CSRA) and air-water exchange models, the contributions of fossil fuel and biomass burning derived polycyclic aromatic hydrocarbons (PAHs) as well as their air-water transport were elucidated. The results showed that fossil fuel-derived PAHs (an average contribution of 89%) presented the net volatilization process at the air-water interface of the Taiwan Strait in summer. Net volatile fluxes of the dominant fluorene and phenanthrene (>58% of the total PAHs) were 27 +/- 2.8 mu g m(-2) day(-1), significantly higher than the dry deposition fluxes (average 0.43 mu g m(-2) day(-1)). The Delta C-14 contents of selected PAHs (fluorene, phenanthrene plus anthracene, fluoranthene, and pyrene) determined by CSRA in the dissolved seawater ranged from -997 +/- 4 parts per thousand to -873 +/- 6 parts per thousand, indicating that 89-100% (95 +/- 4%) of PAHs were supplied by fossil fuels. The South China Sea warm current originating from the southwest China in summer (98%) and the Min-Zhe coastal current originating from the north China in winter (97%) input more fossil fuel PAHs than the Jiulong River estuary (90%) and Xiamen harbor water (93%). The more radioactive decayed C-14 of fluoranthene (a 4-ring PAH) than that of phenanthrene and anthracene (3-ring PAHs) represented a greater fossil fuel contribution to the former in dissolved seawater.