Qingshu Yang

Characterizing the parent and alkyl polycyclic aromatic hydrocarbons in the Pearl River Estuary, Daya Bay and northern South China Sea: Influence of riverine input

Distributions of 31 parent polycyclic aromatic hydrocarbons (PAHs) and 29 alkyl PAHs in surface sediments of the Pearl River Estuary (PRE), Daya Bay (DYB) and northern South China Sea (SCS) were examined to study the influence of riverine input. It was found that the contributions of riverine input to sediment PAHs in PRE was much higher than other areas. However, higher proportion of alkyl PAHs and low molecular weight PAHs in DYB and the northern SCS was observed, indicating their different sources. Nevertheless, the sediment PAHs in PRE were heterogeneous and affected by the hydrodynamic conditions. The high molecular weight PAHs were dominant in PRE and enriched in the depositional area of suspended particular matter (SPM). Moreover, the concentration of PAHs in SPM was similar to those in surface sediments and dominated in water columns. Therefore, SPM played a very important role in transportation and distribution of PAHs in PRE.

Full automatic determination of chlorophenols in water using solid-phase microextraction/on-fiber derivatization and gas chromatography-mass spectrometry

A fully automated combination of solid-phase microextraction and on-fiber derivatization coupled with gas chromatography-mass spectrometry was developed to determine 17 chlorophenols in aqueous samples. Optimal parameters for the automated process, such as fiber coating (polyacrylate), derivatization reagent (N,O-bis(trimethylsilyl) trifluoroacetamide), extraction time (60 min), derivatization time (5 min), incubation temperature (35°C), sample pH (3), and ionic strength (300 g L(-1) of NaCl), as well as desorption time (5 min) and desorption temperature (270°C) were established. The whole procedure took only 90 min and was performed automatically. The shortcomings of silylation derivatives, like incompleteness and instability, were overcome by using solid-phase microextraction on-fiber silylation in this study. The results from both pure water and river water samples showed that the method had a good linearity (r(2) = 0.9993-1.0000), ranging from 0.01 to 100 μg L(-1). The related standard deviations were between 3.6 and 10.0%. The limits of detections and qualifications ranged from 0.03 to 3.11 ng L(-1) and 0.09 to 10.4 ng L(-1) for the CPs, respectively. The proposed method is superior to traditional solid phase extraction procedure.

Distribution and transportation of polycyclic aromatic hydrocarbons (PAHs) at the Humen river mouth in the Pearl River delta and their influencing factors.

Five different water samples were collected from the surface to the bottom layers at the Humen river mouth in the Pearl River delta during the flood and ebb tides in August 2011, respectively. Changes in the distribution and characteristics of polycyclic aromatic hydrocarbons (PAHs) were examined to explore their transportation process. More than 62 types of PAHs were detected in the water columns. The mean concentration of the total PAHs ranged from 849.33 to 1370.53 ng/l and from 629.21 to 2019.91 ng/l during the flood and ebb tides, respectively. Furthermore, 2-ring PAHs were the most abundant species, followed by 3-ring PAHs. There were different composition patterns of the PAHs during the flood and ebb tides. And the transportation process of PAHs was influenced by their sources and different estuarine hydrodynamics. Analysis of the sources of the PAHs indicated that the PAHs were derived from primarily petroleum and coal combustion sources.

Seasonal changes of polycyclic aromatic hydrocarbons in response to hydrology and anthropogenic activities in the Pearl River estuary, China

The behaviours of PAHs (containing 2-6 aromatic rings) in the Pearl River estuary were examined each month in 2011. This study was designed to investigate the abundance of 16 priority PAHs and their response to the seasonal dynamics of anthropogenic activities and hydrological cycles. Monthly mean concentrations of ∑16PAHs in water and suspended particulate matter (SPM) were 88.31ng/L and 252.31ng/L respectively, with higher concentrations in the wet season (April to September). Heavy precipitation in the wet season resulted in relatively increased PAH input via riverine discharges and atmospheric deposition. Seasonal variations in suspended sediment concentration (SSC), temperature and salinity have considerably affected the PAH phase association. Higher SSC in the wet season contributed to higher concentration of the PAHs in SPM, and higher temperature and lower salinity facilitated desorption from SPM. The PAH sources were largely attributed to vehicular emissions, coal combustion and coke ovens.

Recent changes in the sediment regime of the Pearl River (South China): Causes and implications for the Pearl River Delta

1 Institute of Estuarine and Coastal Research, School of Marine Sciences, Sun Yat‐sen University, Guangzhou 510275, China State‐province Joint Engineering Laboratory of Estuarine Hydraulic Technology, Guangzhou 510275, China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China Correspondence Huayang Cai, Institute of Estuarine and Coastal Research, School of Marine Sciences, Sun Yat‐sen University, Guangzhou 510275, China. Email: caihy7@mail.sysu.edu.cn Funding information National Key Research and Development Program of China, Grant/Award Number: 2016YFC0402602; National Natural Science Foundation of China, Grant/Award Number: 41706088; Guangdong Provincal Natural Science Foundation of China, Grant/Award Number: 2017A030310435; Water Resource Science and Technology Innovation Program of Guangdong Province, Grant/Award Number: 2016‐21

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

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.