Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China.
Environ Geochem Health. 2018 Oct;40(5):1941-1953. doi: 10.1007/s10653-017-9969-7. Epub 2017 May 5.
PAHs could be transported to Tibetan Plateau in accompany with atmospheric circulation. The forest regions were found be an important sink for PAHs, while their distributions and migrations in forest are still uncertain. In this study, soil profile samples were collected in southeastern Tibet and the concentrations, distributions, and migration of PAHs in forest region were investigated. The PAHs levels in the forest soils were at the low end of remote sites, ranged from 27.4 to 120.3 ng g on a dry weight based. Due to low ambient temperature and high organic carbon content, enrichment of PAHs was found in higher altitude on north side. According to the soil profiles, the vertical distributions of PAHs in organic layers were mainly influenced by pedogenesis, while the vertical distributions in mineral layers were dominated by downward leaching effect. Enrich factor (EF) of PAHs was estimated, and the values in organic layers were positively correlated with the octanol-air partition coefficients (K ), but EFs in mineral layers decreased with the K values. PAHs in the surface soils on the north side of forest were relatively stable, while the migration of PAHs on the south sides and other clearing sites was more active. The leaching rates of PAHs in clearing site ranged between 1.42 and 29.3%. The results from this study are valuable on the characterization of PAHs in Tibetan Plateau.
多环芳烃可能会伴随大气环流被输送到青藏高原。森林地区被发现是多环芳烃的一个重要汇，但它们在森林中的分布和迁移仍不确定。在这项研究中，采集了藏东南的土壤剖面样品，研究了森林地区多环芳烃的浓度、分布和迁移。森林土壤中的多环芳烃水平处于偏远地区的低端，基于干重的范围从 27.4 到 120.3ng/g。由于环境温度低和有机碳含量高，高海拔的北坡多环芳烃含量较高。根据土壤剖面，有机层中多环芳烃的垂直分布主要受成土作用的影响，而矿物质层中的垂直分布则主要受向下淋溶作用的影响。多环芳烃的富集因子（EF）进行了估计，有机层中的值与辛醇-空气分配系数（Kow）呈正相关，但矿物质层中的 EF 值随着 Kow 值的降低而降低。森林北坡表层土壤中的多环芳烃相对稳定，而森林南坡和其他清理点的多环芳烃迁移则更为活跃。清理点多环芳烃的淋溶率在 1.42 到 29.3%之间。本研究的结果对青藏高原多环芳烃的特征描述具有重要价值。
