PAHs in the Shallow Groundwater of Taihu Plain: Distribution and Sources Identification by Molecular Ratios and Statistical Techniques

摘要

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in shallow groundwater samples collected from 56 locations in Taihu Plain, Jiangsu, were analyzed. Hierarchical cluster analysis (HCA) and molecular ratios were used to characterize their possible pollution sources. Concentrations of total priority 16 PAHs in shallow groundwater samples ranged from below method detection limits (＜MDLs) to 32.45 μg/L with the average value of 4.42 μg/L, which was predominated by three and four-ring PAHs. High contents of PAHs were found in the vicinity of industrial areas. Ratios of specific PAH compounds including phenanthrene/anthracene (Phe/Ant), flnoranthene/pyrene (FL/Pyr), chrysene/benzo[a])/anthracene(Chr/BaA), low-molecular-weight PAH/high-molecular-weight PAH (LPAH/HPAH) were calculated to evaluate the possible sources of PAH contamination. These ratios reflect a mixed pattern of pyrolytic and petrogenic inputs of PAHs with different proportions in the shallow groundwater. Hierarchical cluster analysis (HCA) results revealed that the wells can be divided into 5, 5, 6 clusters with the three clusters I having the largest number wells in each city respectively. FL, AcPy, Acp, Phe and Bap in Changzbou, BP, BaA and Bap in Wuxi, and for AcPy and Flu in Suzhou had higher Pearson correlation, which means that those PAHs in each city might come from the same sources.