Comparison of Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Different Environmental Media in the Urban Area of Daqing City

Abstract

In order to investigate the various pollution characteristics and sources of polycyclic aromatic hydrocarbons (PAHs) in different environmental media, 23 street dust samples and four soil samples were collected in October 2012 in Daqing City. After extraction by Dionex ASE300 and purification, the content of the US EPA priority pollutants[16 individual PAH and total PAHs (ΣPAHs)] was determined by using gas chromatography-mass spectrometry (GC/MS). The results showed that the range of ΣPAHs content in street dust was 579.5-4656.7 ng·g-1, and the average content was 1839.7 ng·g-1. The mass percentage of PAHs in the street dust in different functional areas in Daqing showed a similar mass ratio range, with the average mass percentage of low ring (2-3 rings) PAHs of 37.9%, medium ring (4 rings) PAHs of 37.3%, and high ring (5-6 rings) PAHs of 24.8%. However, low ring PAHs, with mass ratios of 69.3%-99.97%, overwhelmingly dominated the Daqing soil, Daqing lake sediment, Daqing lakes, and Daqing ponds (data from literature). The distribution of ΣPAHs content was not significant among different functional areas and was closely related to the type of the plants around the sampling sites. The isomer ratio method confirmed that the sources of PAHs in the street dust in the study area were mixed sources, including oil spills, fuel oil combustion, and coal/biomass burning. Positive matrix factorization (PMF) results showed that the PAHs in the street dust in the center of Daqing originated from coal combustion, oil spill sources, industrial sources, and traffic sources, with contribution rates of 30.1%, 26.9%, 23.6%, and 19.3%, respectively, which were not exactly the same trend as that in other media.