Soil is the most important LEE011 for PAHs in the environment (Yin et al., 2008). This is because PAHs are sparingly soluble, readily adsorbed by soil particles, and resist degradation (Tang et al., 2005). It has been estimated that approximately 90% of total residues remain in the soil (Hu et al., 2013). Urban areas are very populated and are accompanied by an increased production of industrial waste, traffic pollution, and household garbage, which produce many PAHs and other pollutants that migrate into urban soils through dry and wet atmospheric deposition. Generally, the concentration of PAHs in urban areas is significantly higher than in suburban or rural areas (Zhang et al., 2006, Wang et al., 2007a and Wang et al., 2007b). Consequently, the soil system is a major reservoir and a good indicator of environmental pollution and environment risk for human exposure (Jiang et al., 2009). However, the health risk of exposure to PAHs from urban soils is not well understood.
In this study, we investigated the PAH concentrations in urban soils of Nanjing. The specific objectives were as follows: (1) to measure the concentrations of PAHs from urban to rural soils in Nanjing, (2) to identify the possible sources of PAHs by positive matrix factorization (PMF), (3) to analyze the spatial distribution of PAHs by using Kriging interpolation, and (4) to evaluate the human health risk of PAHs in Nanjing soils.