Distribution, Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Sediments from Zhushan Bay Littoral Zone, Lake Taihu

Surface sediment samples were collected from lakeside zone of Zhushan Bay, Lake Taihu, of which 10 samples were collected from the littoral zone and one sample was collected from the center of the lake. The concentrations of 16 US EPA-priority-controlled polycyclic aromatic hydrocarbons (PAHs) were analyzed by GC-MS. The results showed that PAHs content varied from 61.2 to 2 032.3 ng/g, and the mean value was 1 131.5 ng/g. The spectra of PAHs showed that 4 rings and 5-6 rings were predominant ones in littoral zone, accounting for 28.6% and 60.9%, respectively, while 2-3 rings PAHs were predominant in the center of the lake, accounting for 88.1%. The source of PAHs in littoral zone sediments was mainly attributed to high-temperature combustion of coal, oil and other fossil fuels, but that in center of the lake was mainly attributed to oil spill. No significant PAH ecological risk was found in littoral zone of Lake Taihu according to ecological risk assessment. However, some PAH concentrations exceeded the effects range low (ERL) in some sampling sites. Potential harmful effects on organisms might exist, and ecological risk should be prevented.