裂隙介质VOCs赋存迁移特征与场地修复难点

梳理了裂隙介质污染的研究方法，分析裂隙介质中VOCs的赋存迁移特征与修复技术原理，结合我国实际情形分析该类场地修复治理的难点并提出相关建议.裂隙介质场地中，对流弥散、吸附解吸、跨界输移的协同作用影响VOCs的环境行为与归趋.在理论层面，基于分离、化学氧化与生物转化过程的修复原理能够实现裂隙中VOCs的去除，但由于氧化还原产物堵塞、吸附态污染物反向扩散等原因，裂隙介质VOCs污染修复过程可能存在拖尾、修复后可能存在反弹的问题.与孔隙介质场地相比，不确定性是造成裂隙介质场地修复困难的主要原因，主要体现在场地调查阶段样品代表性差、修复治理过程中裂隙对污染物的阻滞作用所致传质受限、污染物易发生跨介质迁移风险等方面.后续研究亟需在充分认识裂隙污染物迁移转化机制的基础上，进一步探索适合我国修复与再利用实际情形的修复和风险管控模式.

VOCs in fractured aquifers: presence,migration characteristics,and difficulties for contaminated site remediation

This review summarizes experimental methods in this field, assesses migration characteristics of VOCs in fractures, and analyzes mechanisms involved in the remediation of fractured aquifers. Furthermore, implications for contaminated site remediation are proposed. Advection-dispersion, adsorption-desorption and cross-media migration affect the fate of VOCs in fractured aquifers. Both crack clogging by chemical oxidation products and back diffusion of trapped VOCs affect the remediation efficiency, leading to tailing and rebounding of the remedy project in fractured aquifers. Low representativeness of environmental samples, limited mass transfer rate of reagents and substrates, and cross-media transport are the major obstacles hindering fractured aquifer remediation, where future works must spare no effort to overcome.