Abstract:

Based on the 6 greening tree species in the 4 functional areas of Fuxin City, Picea asperata, Pinus tabuliformis, Ulmus pumila, Syringa oblata, Prunus cerasifera and Ginkgo biloba were the test material, determining the amount of dust retention per unit area of leaves by elution. The mass concentration of heavy metals Cd, Cr, Cu, Ni and Pb was determined by using inductively coupled plasma mass spectrometry (ICP-MS). Explored the retention capacity of the leaves of different greening tree species to atmospheric particulate matter and heavy metals, and analyzed the correlation and possible sources of heavy metals in the leaf dust. The results showed that: (1) The amount of dust retention in the leaves of the six greening tree species has obvious differences due to seasonal changes or different functional areas. During the sampling period, the average dust retention capacity of the tree species was ranked as follows: Picea asperata>Ulmus pumila>Pinus tabuliformis>Syringa oblata>Prunus cerasifera>Ginkgo biloba. Among them, the evergreen coniferous Picea asperata and Pinus tabuliformis had higher dust retention in spring and winter than summer and autumn, and the annual average dust retention per unit leaf of Picea asperata is 1.77 times that of Pinus tabuliformis. The dust retention of deciduous broad-leaved Ulmus pumila in summer and autumn is 3.37 and 3.66 times that of Ginkgo biloba, respectively. (2) The ability of the leaves of greening tree species to retain heavy metals was closely related to the season and functional area. In spring and winter, Picea asperata had a strong retention capacity for 5 heavy metals. In summer and autumn, Ulmus pumila and Prunus cerasifera had better retention effects. The heavy metals in the leaves of tree species that contain the most dust from the environmental protection bureau, the main campus of Liaoning Technical University, and the north campus of Liaoning Technical University were Pb, Cr and Cu, respectively, the open-pit mines were Cd and Ni. (3) Correlation analysis of heavy metals in leaf dust of greening tree species showed that Cd-Ni, Cd-Pb, and Ni-Pb all showed a significant positive correlation, indicated that Cd, Ni and Pb had strong homology. The principal component analysis showed that the heavy metals in the leaf dust of greening tree species in Fuxin mainly come from coal combustion in power plants and heating and thermal power plants, exhaust emissions from urban motor vehicles and industrial smoke from tanning. The conclusions of this study will provide a scientific basis for the optimal selection of greening tree species and the prevention and control of air particulate pollution in Fuxin.

Key words: atmospheric particulate matter, greening tree species, retention capacity, heavy metal, correlation, source

摘要：

以阜新市4个功能区6种绿化树种云杉（Picea asperata）、油松（Pinus tabuliformis）、金叶榆（Ulmus pumila）、紫丁香（Syringa oblata）、紫叶李（Prunus cerasifera）和银杏（Ginkgo biloba）为试材,采用洗脱法测定叶片单位面积滞尘量,使用电感耦合等离子质谱法（ICP-MS）测定重金属Cd、Cr、Cu、Ni及Pb的质量浓度,探究了不同绿化树种叶片对大气颗粒物及重金属的滞留能力,并分析了叶面尘中重金属相关性及可能来源。结果表明,（1）6种绿化树种叶片滞尘能力因季节变化或功能区不同而产生明显差异。采样期间,阜新市绿化树种滞尘能力排序为：云杉>金叶榆>油松>紫丁香>紫叶李>银杏,其中,常青针叶类的云杉和油松在春、冬季的滞尘量高于夏、秋季,且云杉年平均单位叶片滞尘量是油松的1.77倍;落叶阔叶类的金叶榆在夏、秋两季的滞尘量分别是银杏的3.37、3.66倍。（2）绿化树种叶片滞留重金属的能力与季节、功能区密切相关。春、冬季,云杉对5种重金属的滞留能力均较强;夏、秋季,则金叶榆和紫叶李的滞留效果较好;环保局、辽工大主校区、辽工大北校区树种叶片滞尘中含量最多的重金属分别为Pb、Cr、Cu,露天矿最多的则为Cd和Ni。（3）绿化树种叶面滞尘中重金属相关性分析表明Ni-Pb、Cd-Ni、Cd-Pb之间均呈现显著正相关性,表明Cd、Ni、Pb同源性很强;主成分分析得出阜新市绿化树种叶面滞尘中重金属主要来源于电厂与采暖热电厂煤炭燃烧、城市机动车尾气排放及鞣革等重点工业排烟。该研究结论可为阜新市绿化树种优化筛选和大气颗粒物污染防控提供科学依据。

关键词: 大气颗粒物, 绿化树种, 滞留能力, 重金属, 相关性, 来源