State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Chemosphere. 2019 Sep;231:571-578. doi: 10.1016/j.chemosphere.2019.05.181. Epub 2019 May 23.
Previous work documented that forest plays an important role in the deposition of persistent organic pollutants (POPs) in the southeast Tibetan Plateau (TP) due to the "forest filter effect". However, forest types in the southeast TP are entirely different and the influence on POPs fate and forest filter effect by different forests remains unclear. This study focused on the distribution and transfer of organochlorine pesticides (OCPs) in soil of different forest types (quercus, birch, fir, and spruce dominated forests) in Mt. Shergyla, southeast TP under similar environmental and meteorological conditions. Total levels of ∑HCHs, ∑DDTs and HCB in soils ranged from < LOD to 2.25 ng/g dry weight (dw), < LOD-10.2 ng/g dw, and < LOD-0.95 ng/g dw, respectively. Concentrations of OCPs in humus layers were significantly higher than those in mineral layers in the four forest types. Relatively higher ∑DDTs concentrations were found in soil profile of broadleaved birch forest, while higher concentrations of ∑HCHs and HCB were found in soil profile of coniferous fir forest, and the same trend was observed in fresh leaf samples. Air-to-ground fluxes and mobility of OCPs in the four forest types were also evaluated. Relatively higher fluxes were found in fir forests than in other forest types, suggesting that fir forest could be more effective to transfer OCPs from the air into soil in the southeast TP. The findings in this study would be helpful for improving model simulation of POPs fate in different forest ecosystem.
先前的研究表明，由于“森林过滤效应”，森林在藏东南高原（TP）持久性有机污染物（POPs）的沉积中起着重要作用。然而，藏东南TP 的森林类型完全不同，不同森林对 POPs 归宿和森林过滤效应的影响尚不清楚。本研究主要关注在相似的环境和气象条件下，藏东南色季拉山不同森林类型（栎木林、桦木林、冷杉林和云杉林）土壤中有机氯农药（OCPs）的分布和迁移。土壤中∑HCHs、∑DDTs 和 HCB 的总浓度范围为 < LOD-2.25ng/g 干重（dw）、< LOD-10.2ng/g dw 和 < LOD-0.95ng/g dw。四种森林类型中，腐殖质层中 OCPs 的浓度明显高于矿物质层。阔叶桦木林中∑DDTs 的浓度相对较高，而在针叶冷杉林中∑HCHs 和 HCB 的浓度较高，在新鲜叶片样本中也观察到相同的趋势。还评估了四种森林类型中 OCPs 的气-地通量和迁移能力。冷杉林中的通量相对较高，表明在藏东南地区，冷杉林可能更有效地将 OCPs 从空气中转移到土壤中。本研究的结果有助于改进不同森林生态系统中 POPs 归宿的模型模拟。
