摘要
植被富集环境中持久性有机污染物(POPs)的途径有多种,其中以植物叶片富集大气POPs为主要的途径。因此,植被(地衣、苔藓、草地、松针和树皮)被广泛用作被动采样器,以动态地监测不同时间和空间尺度上大气POPs的污染水平与特征。大气—植物的气体交换过程影响着POPs的大气传输,进而影响POPs在区域甚至全球尺度上的空间分布。研究发现,植被是POPs全球循环的"汇区"。植物富集的POPs会进入陆生食物链,并随食物链营养级的升高而产生生物放大效应,对人体健康产生潜在的威胁。本文简要介绍了植被对POPs富集的研究进展,综述了地衣、苔藓和草地作为被动采样器监测大气POPs时空分布的研究,并指出了目前研究中亟待解决的问题及未来可能的研究方向。
Plants can absorb persistent organic pollutants （POPs） from air and soil. Roots sorption is one of uptake processes, while evidence showed that POPs absorbed by roots was hardly transferred to the aerial tissues of the plant. The POPs re-volatilized from soil may only influence the parts of plants near the surface of the ground. Compared to the absorption from soil, the absorption of atmospheric POPs by foliage raised more concern. The airborne POPs can be accumulated by plant leaves by wet and dry deposition, which is the main pathway of the atmospheric POPs entering the aerial parts of plants. Air-plant exchange equilibrium is an important state that determines the direction of gas exchange between air and plant. The airbome POPs partition onto plant and approach plant gas-phase equilibrium rather rapidly, within less than 6 days of exposure. Besides exposure time, other environmental factors （temperature, wind speed, humidity, etc.） and the shape, areas and life time of the leaves have impacts on the air-plant exchange equilibrium of POPs. Through the air-plant exchange the airborne POPs were fixed by the plants and finally transferred into soil by falling off the leaves. Therefore, the air-plant exchange of POPs will influence the long-range atmospheric transport and the regional, even global distribution of POPs. Plants such as lichens, mosses, grass and forest have been used as passive samplers to monitor the levels of atmospheric POPs on different time scales and reflect the spatial distribution of POPs. Lichens and mosses are extensively used in environmental pollution studies especially in the polar region, since their collection is relatively easy. For grass, different species have the same ability to absorb the airborne POPs, which was used as bioonitor to compare the POPs in different regions over the world. Numerous studies indicated that plants act as a ＂sink＂ for global cycling of POPs. The POPs absorbed by plants will enter the terrestrial food chains through the consumption of plants by animals and will be transported from one trophic level to a higher one, which will result in bio-concentration and even pose potential threat to the health of humans. However, there are a few studies focusing on the bio-concentration of POPs in the terrestrial food chains currently and most of them utilize models to simulate the bio-concentration process. In this paper, the research progress on the accumulation of POPs by plants including the ways of POPs entering the plants and the air-plant exchange of the airborne POPs were reviewed; the advantage and disadvantage of vegetation passive samplers （lichens, mosses and grass） were discussed. We also pointed out the problems needed to be solved in further studies.
出处
《地理科学进展》
CSCD
北大核心
2013年第10期1555-1566,共12页
Progress in Geography
基金
国家自然科学基金项目(41222010
41071321
41201489)
