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

Abstract

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 μg m day, significantly higher than the dry deposition fluxes (average 0.43 μg m day). The ΔC contents of selected PAHs (fluorene, phenanthrene plus anthracene, fluoranthene, and pyrene) determined by CSRA in the dissolved seawater ranged from -997 ± 4‰ to -873 ± 6‰, 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 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.

Distribution of Freely Dissolved Polycyclic Aromatic Hydrocarbons in the Yellow Sea: Application of Improved Passive Sampling Technique

“…The dissolved PAH levels were similar to those detected from 2004 to 2007 (range 5.3-46; mean 8.0 ng/L) and in 2019 (range 12-17; mean 13 ng/L) in the Yellow Sea (MOE 2008;Jang et al 2021) and in the northern South China Sea (range 0.98-13; mean 4.7 ng/L) (Cai et al 2018). In some marginal seas of China including the northern South China Sea, the East China Sea, and the Yellow Sea, PAH concentrations were relatively higher, by a factor of 4, than those in our study (Ya et al 2017a(Ya et al , 2018. This is because these studies were conducted not only in marginal seas but also in coastal areas with high levels of PAHs.…”

Triple Isotopes (δ13C, δ2H, and Δ14C) Compositions and Source Apportionment of Atmospheric Naphthalene: A Key Surrogate of Intermediate-Volatility Organic Compounds (IVOCs)

“…Top-down constraints with the intrinsic isotopic compositions of the specific compounds can help to narrow the uncertainties in source analyses. Stable carbon isotope (δ 13 C) analysis on specific compounds has been widely used to study the origins and sinks of contaminants. − Meanwhile, the stable hydrogen isotope (δ 2 H), in comparison with δ 13 C, could be a more powerful tool for source apportionment because δ 2 H values of some compounds emitted from different sources or produced through different conversion processes have a much greater degree of differentiation. − In addition to these stable isotopes, compound-specific radiocarbon analysis (CSRA) can distinguish sources of target compounds between fossil fuel (void of 14 C) and nonfossil (contemporary 14 C) sources unambiguously. , Bosch et al applied a triple-isotope system (δ 13 C, Δ 14 C, and δ 2 H) to elucidate the relative contributions of four major sources of PAHs (not including Nap) in central European forest soils. As far as we know, there are still no reports about the triple-isotope composition of atmospheric two-ring PAHs.…”

“…18−22 In addition to these stable isotopes, compound-specific radiocarbon analysis (CSRA) can distinguish sources of target compounds between fossil fuel (void of 14 C) and nonfossil (contemporary 14 C) sources unambiguously. 23,24 Bosch et al 25 applied a triple-isotope system (δ 13 C, Δ 14 C, and δ 2 H) to elucidate the relative contributions of four major sources of PAHs (not including Nap) in central European forest soils. As far as we know, there are still no reports about the triple-isotope composition of atmospheric two-ring PAHs.…”

Method Development for Low-Concentration PAHs Analysis in Seawater to Evaluate the Impact of Ship Scrubber Washwater Effluents

“…It is slightly lower than the adjacent seas such as the South China Sea (4.7 ng/L) [23] and the south eastern Japan Sea (6.0 ± 1.8 ng/L) [27]. However, it is lower than the Gulf of Mexico (35.5 ± 9.0 ng/L) [28], the Xiamen coast, China (62 ng/L) [29], the Hainan Island coast, China (104 ± 38 ng/L) [30], and the Taiwan Strait (62 ± 8.3 ng/L) [31]. The distribution of PAHs concentrations in seawater in different regions of the world shows that nearshore seas with anthropogenic influence are higher than the adjacent sea and oceanic areas.…”