Impacts of estuarine mixing on vertical dispersion of polycyclic aromatic hydrocarbons (PAHs) in a tide-dominated estuary

• Published in: Marine pollution bulletin Vol. 131; no. Pt A; pp. 276 - 283
• Main Authors: Liu, Feng, Hu, Shuai, Guo, Xiaojuan, Niu, Lixia, Cai, Huayang, Yang, Qingshu
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-06-2018; Elsevier BV
• Subjects: Aromatic compounds; Aromatic hydrocarbons; Brackishwater environment; China; Composition; Density stratification; Dispersion; Distribution; Dynamic mechanism; Environmental Monitoring - methods; Estuaries; Estuarine dynamics; Estuarine environments; Estuarine mixing; Marine pollution; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; River mouth; River mouths; Rivers; Salinity; Salinity effects; Salinity stratification; Seasonal variation; Seasonal variations; Seasons; Stratification; Surface layers; Tide-dominated estuary; Tides; Vertical dispersion; Vertical distribution; Water Pollutants, Chemical - analysis; Pearl River Estuary; Estuarine mixing; Polycyclic aromatic hydrocarbons; Vertical dispersion; Dynamic mechanism; Tide-dominated estuary
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2018.04.036

To examine the impacts of estuarine mixing on the dispersion of polycyclic aromatic hydrocarbons (PAHs), seasonal variations in the vertical distribution of dissolved PAHs in the Humen River mouth of the Pearl River Estuary, which is a tide-dominated estuary, were thoroughly examined. An analysis of the vertical distribution of the concentration, composition and sources of PAHs indicates enhanced mixing of PAHs in January relative to June, which is strongly related to seasonal variations in the magnitude of estuarine mixing. Furthermore, the vertical distribution of PAHs initially indicated an increase and then a decrease from the surface layer to the bottom layer. In general, estuarine mixing promotes the vertical dispersion of PAHs, causing a more even PAHs distribution, while salinity stratification can trap PAHs, resulting in higher PAHs concentrations. Our study indicates that salinity variability stimulates significant dynamic effects regarding the dispersion of PAHs within estuarine environments.
•Estuarine mixing controlled vertical dispersion of PAHs in the water column.•Highly estuarine mixing promoted the vertical dispersion of PAHs.•Salinity stratification inhibited the vertical dispersion of PAHs.•PAH trapping caused by salinity stratification was detected.