Occurrence of polycyclic aromatic hydrocarbons in the estuarine sediments of the Taihu Lake and their associated toxic effects on aquatic organisms

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous toxic organic pollutants in the natural environment that are strongly associated with socioeconomic activities. Exploring the distribution, sources, and ecological toxicity of PAHs is essential to abate their pollution and biological risks. The 16 priority PAHs in different lakeside city estuarine sediments in the northern Taihu Lake in China were determined using gas chromatography-mass spectrometry. Results showed that total concentrations of PAHs (ΣPAHs) ranged from 672.07 to 5 858.34 ng g^?1, with a mean value of 2 121.37 ng g^?1. High-molecular-weight PAHs (4–6 rings) were dominant, accounting for 85% of the ΣPAHs detected. Due to the barrier of gate/dam in the estuarine area, the concentrations of PAHs in the sediments were significantly different between the river mouth and lake side. Changes in total organic carbon (TOC) content and the spatial distribution of PAHs in the sediments were consistent. Sediment pollution assessment explored using the fuzzy evaluation model indicated 75% of slight PAH pollution. Some estuarine sediments (22%) concentrated in the east of the Wuli Lake in the Meiliang bay of the Taihu Lake were moderately or heavily polluted. The PAHs may lead to occasional detrimental biological consequences in the area. Diagnostic ratios and principal component analysis-multiple linear regression suggested vehicle emission and natural gas combustion as the primary PAH contributors (81%).