The quantitative study of urban-rural gradients for persistent organic pollutants (POPs) is extremely important to understand the behavior of POPs as well as for ecological risk assessment and management. In this study, a practical urban-rural gradient model (URGM) was developed using atmospheric point source diffusion combined with a fugacity approach to test potential mathematical relationships among urban and rural soils. The mean value of polycyclic aromatic hydrocarbons (PAHs) for urban soils (0–2-km sites) was 570.80 ng/g, and was approximately 3.5 times higher than rural soils (30–50 km sites). Significant linear correlations were found between the amounts of PAHs in the surface soil and the city population and between the soil concentration and artificial surface area. Urban-rural PAH concentrations were simulated by the URGM and calibrated by city population and land-cover data, with average relative errors of 12.84%. The results showed that the URGM was suitable for simulating urban-rural PAH concentrations at a regional scale. The combustion of fossil fuels, biomass, and coal was the main source of soil PAHs in the study area, and the characteristic ratios of PAHs indicated a transition trend from pyrogenic to petrogenic sources along the urban-rural transects. This study thus provides a combined method for quantifying urban-rural gradients of PAHs and can thereby promote quantitative research on coupling among land cover, socio-economic data, and POP concentrations.
This is the author’s version of a work that was accepted for publication in Journal of Environmental Management. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Management, 249, 2019 DOI: 10.1016/j.jenvman.2019.109406
