Ten sampling points were distributed approximately equidistantly in the Dajiuhu lake wetland, and soils from the depths 0-10 cm, 10-20 cm, and 20-30 cm were collected in April 2012. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the remote mountain wetland shallow soils, and 16 kinds of USEPA priority controlled polycyclic aromatic hydrocarbon (PAH) pollutants were identified. The ∑16PAHs content ranges of the shallow soils of this region were 48.55-984.73 ng·g-1, 14.36-806.47 ng·g-1, and 12.84-1191.53 ng·g-1 in the 0-10 cm, 10-20 cm, and 20-30 cm layers, with a mean of 302.94 ng·g-1, 142.98 ng·g-1, and 208.68 ng·g-1 in the three layers, respectively. The concentrations of seven carcinogenic PAHs ranged from 21.20-844.29 ng·g-1, 2.96-592.06 ng·g-1 and 0.66-964.70 ng·g-1 in the three soil layers, with means of 197.25 ng·g-1, 93.16 ng·g-1, and 147.16 ng·g-1 that accounted for 65.12%, 65.13%, and 69.08% of the total PAHs in the three soil layers, respectively. The concentrations of PAHs in the areas with peat were significantly higher than that in the soil. PAHs having 4-6 rings were the dominant ones. The ratios IcdP/(IcdP+BghiP) and Pyr/BaP showed that the PAHs in the shallow soil form the Dajiuhu lake wetland mainly came from burning fossil fuels and wood. In recent years, the entry of tourist vehicles has contributed significantly to the increase in PAHs. The regression analysis on peat surface layer single body PAH and total PAHs showed that Chr, BbF, IcdP, and BaA could be used as a signaling property of mountain wetland PAH pollution.
Keywords: Dajiuhu Lake; PAHs; composition characteristics; mountain wetland; source apportionment.