title: Polycyclic aromatic hydrocarbons in soils of Beijing and Tianjin region: vertical distribution, correlation with TOC and transport mechanism.
abstract: The contents and distribution of 20 polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic hydrocarbons (HAHs) were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs (HMWPAHs) and the correlation between total organic carbon (TOC) and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil (< 40 cm), with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.
authors.affiliation: PetroChina Changqing Oilfield Company, Oil Production Plant No. 1, Yanan 716000, China. hefengpeng612726@163.com
authors.forename: Fengpeng
authors.initials: F
authors.lastname: He
authors.forename: Zhihuan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yunyang
authors.initials: Y
authors.lastname: Wan
authors.forename: Song
authors.initials: S
authors.lastname: Lu
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Bu
mesh_terms: D002681:China; D008401:Gas Chromatography-Mass Spectrometry; D011083:Polycyclic Compounds / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D011083:Polycyclic Compounds; D012989:Soil Pollutants