Wang, F;
Zhao, D;
Zhang, S;
Feng, T;
Wang, H;
Guo, Z;
Ma, L;
(2023)
Gas-particle partitioning and air-water exchange of polycyclic aromatic hydrocarbons in the Three Gorges Reservoir, southwest China.
Atmospheric Environment
, 299
, Article 119646. 10.1016/j.atmosenv.2023.119646.
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Abstract
A 30 m vertical drawdown water level fluctuation zone (WLFZ) was formed annually due to seasonal water impoundment in the Three Gorges Reservoir (TGR) in Southwest China. In this study, a super site in downstream of WLFZ, ∼200 km off the Three Gorges Dam, was used to investigate the seasonally gas-particle partitioning and air-water exchange of USEPA 16 polycyclic aromatic hydrocarbons (16 PAHs). The average concentrations of 16 PAHs in the particle phase were 66.63 ± 9.15 ng/m3 in winter and 8.43 ± 2.95 ng/m3 in summer. In the gas phase, they were 28.47 ± 4.79 ng/m3 in winter and 10.57 ± 1.51 ng/m3 in summer. In the dissolved phase of surface water, they were 38.65 ± 6.37 ng/L in winter and 56.53 ± 8.86 ng/L in summer. The logarithmic gas-particle partitioning coefficient (lgKp) was negatively correlated with the logarithmic subcooled liquid vapor pressure (lgPL0). While the lgKp was positively correlated with logarithmic octanol-air distribution coefficient (lgKOA). These two regressions both indicated un-equilibrium of gas-particle partitioning of PAHs in the atmosphere. Applying “Whitman two-film resistance model” to our datasets shows that 3-ring PAHs had a net volatilization from water to air (2.74–6.43 ng/m2/d), and 4 ∼ 5-ring PAHs favored deposition from air to water (−0.614 to −0.413 ng/m2/d). The water as a potential ‘source’ for 3-ring and a ‘sink’ for 4 ∼ 5-ring PAHs was thereby revealed. The results of this study are crucial for understanding atmospheric gas-particle partitioning of PAHs and for revealing the factors and mechanisms governing their geochemical cycling at air and water interfaces.
| Type: | Article |
|---|---|
| Title: | Gas-particle partitioning and air-water exchange of polycyclic aromatic hydrocarbons in the Three Gorges Reservoir, southwest China |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.atmosenv.2023.119646 |
| Publisher version: | https://doi.org/10.1016/j.atmosenv.2023.119646 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | PAHs; gas-particle partitioning; air-water exchange; Three Gorges Reservoir region (TGRR) |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10167016 |
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