Source Apportionment of Polycyclic Aromatic Hydrocarbons in Agricultural Soils of Yanqing County in Beijing, China

Abstract

Guanting Reservoir in Yanqing County is a strategic drinking-water resource for Beijing, China. The agricultural soil samples (0 cm to 20 cm) were collected to determine the concentration, compositional profiles, and sources of polycyclic aromatic hydrocarbons (PAHs) surrounding the reservoir. The average measured PAH concentration was 140 ± 85.7 μg kg−1 (CV = 0.45) (dry weight or dw; n = 48; shown as arithmetic mean and standard deviation), which is lower than most of the results reported in literature. The PAH compositional profiles were dominated by 3- and 4-ring compounds, particularly phenanthrene (PHE), fluoranthene (FLA), fluorene (FLO), and pyrene (PYR). The PAH sources were estimated by analyzing the corrected ratios of isomeric PAH species derived using the multimedia fugacity model and principal component analysis/multiple linear regression (PCA/MLR). The corrected isomeric ratios of FLA/(FLA+PYR) and anthracene (ANT)/(ANT+PHE) indicate that combustion processes are the major sources of PAHs in the soil. Three principal components were identified as main sources, representing coal burning and traffic exhaust, biomass combustion and coking, and a source labeled “other,” which contribute 54%, 40%, and 6% of the total PAH, respectively (α = 0.05). Moreover, except those from local biomass burning, other PAHs were primarily deposited in the soil from distant sources via atmospheric transportation.