废旧汽车拆解区土壤中多环芳烃垂向分布特性

Vertical Distribution of Polycyclic Aromatic Hydrocarbons in Abandoned Vehicles Dismantling Area Soil

研究分析了废旧汽车拆解区土壤剖面的美国EPA优控的16种多环芳烃的纵向分布.结果表明,表层土壤中16种多环芳烃总含量达到了17 323 ng·g-1,其中芘（Pyr）、苯并[a]蒽（BaA）、芴（Flu）含量最高,分别达到11 820、1 234和1 083 ng·g-1.汽车拆解区表面和土壤深度为10 cm的土壤均达到了重度污染级别;深度在50~350 cm之间的土壤为轻度至中度污染,当土壤深度超过400 cm,土壤基本未受到污染.但是,7种致癌性PAHs（Chr、BaA、BbF、BkF、BaP、DahA、IcdP）总量在土壤深度达到850 cm时仍有34.15 ng·g-1.随着土壤深度的增大,多环芳烃含量急剧降低,当土壤深度超过300 cm,三环的菲（Phe）、荧蒽（Fl）和二氢苊（Ace）成为优势组分.土壤剖面菲（Phe）/蒽（Ant）比值和荧蒽（Fla）/芘（Pyr）、Fluo/Pyr、BaA/（BaA＋Chr）等参数表明,土壤表面的多环芳烃主要来源于石油污染.

In order to study the contamination by the U. S. EPA 16 priority polycyclic aromatic hydrocarbons （PAHs） in the soil of the end-of-life vehicle dismantling area, soil samples with vertical depth of 0-1000 cm were collected and analyzed. The concentrations of EPA 16 priority PAHs were determined in soils samples. The results showed that total concentrations of PAHs were 991 ng.g-1 in surfieial samples, with the highest concentrations detected for pyrene, benzo[ a] anthracene and fluorine, reaching 11 820, 1 234 and 1 083 ng.g-1 , respectively. The soils with the depth range of 0-10 cm were heavily polluted by PAHs, and the soils in the depth range of 50-350 cm were moderately or slightly polluted by PAHs. It seems that there was no PAHs pollution when the soil depth was over 400 cm. However, it was noted that the total concentration of 7 carcinogenic PAHs including chrysene （Chr） , benzo[ a] anthracene （BaA） , Benzene and （b） fluoranthene（BbF） , Benzene and （k） fluoranthene （BkF） , Benzo [ a] pyrene （BaP） , Diphenyl and [ a, hi anthracene（DahA） , Indene and [1,2,3-CD] pyrene （IedP） was still as high as 34.15 ng.g-~ in soil with a depth of 850 era. The contents of PAHs decreased sharply with the increase in vertical depth. Low-ring PAHs such as phenanthrene, Fluoranthene and acenaphthene became the priority compounds when the depth was over 300 cm. The ratios of Phe/Ant and Fla/Pyr demonstrated that the PAHs in the soil profiles could be primarily sourced from petroleum pollution.