持久性有机污染物在森林生态系统中的环境行为研究

持久性有机污染物(POPs)具有环境持久性和半挥发性, 可以在区域及全球范围内传输和分布。森林植被和林下土壤富含有机质, 森林生态系统因此成为POPs主要的储存库之一。植被叶片可快速吸附大气POPs, 并通过叶片凋落、雨水冲刷和干沉降等过程加强或加速大气POPs 向地面的沉降, 并使森林土壤成为POPs 的“汇”, 从而形成所谓的“森林过滤效应”, 进而影响POPs 在全球的分布。进入森林的POPs 在森林生态系统中将经历一系列的环境过程。本文简要介绍了森林过滤效应的特征和影响因素, 综述了叶片对大气POPs 的吸附、叶片凋落和干湿沉降、POPs 在土壤中的迁移和损失等3 个主要环境过程的研究进展, 报道了松针、树皮和苔藓作为被动采样器反映的森林POPs空间分布趋势。最后, 提出了森林POPs研究中亟待解决的科学问题, 并指出未来中国森林POPs研究的可能方向。

Environmental behaviors of the persistent organic pollutants in forest ecosystem

Persistent organic pollutants (POPs) are a series of persistent, semi-volatile compounds that are found throughout the global environment. Forest plays an important role in the environmental fate of POPs. Because of its high organic content, forest is regarded as a sink for POPs. The primary effect of forest is pumping chemicals from the atmosphere to the forest soil, which is called the "forest filter effect". POPs are exposed to various processes in forest, including adsorption in leaves, leaf litter and dry and wet deposition, and leaching or loss in soil. Some vegetation tissues, for example, pine needles, mosses and tree barks, are observed to accumulate POPs, and have been employed for monitoring regional and global distribution of POPs. This paper reviewed the progress on the above-mentioned scientific topics and discussed the overlooked topics in current researches. In addition, we pointed out the work needed for further studies on POPs, especially in forest of China.