沉积物再悬浮-重金属释放机制研究进展

水-沉积物界面重金属迁移和转化行为已成为水环境质量研究的热点。因自然、生物、人为活动等驱动的沉积物再悬浮使得沉积物颗粒吸附和结合的重金属可能通过吸附-解吸平衡和氧化还原反应而释放进入上覆水体。随着外在污染源输入逐步得到控制,沉积物再悬浮释放重金属将成为水体重要的内在污染源而对水环境质量和水生生物产生影响。本文综述了最近几年的相关研究文献,对沉积物再悬浮的动力来源及发生机制、再悬浮-重金属释放机制及主要影响因素进行了阐述,探讨了该领域未来可能的研究方向。相关研究发现,当干扰切应力大于沉积物的临界切应力值时,沉积物再悬浮发生,且再悬浮颗粒量随干扰切应力的增强而增大;再悬浮使还原态沉积物暴露于有氧环境,有机质和硫化物的氧化是沉积物结合态重金属释放的主要机理,而沉积物颗粒电性吸附的重金属则通过解吸进入水体;切应力大小、再悬浮水体理化性质、沉积物理化性质以及微生物活性等因素调控着沉积物吸附态或结合态重金属的释放。本文指出再悬浮沉积物释放重金属的去向（再分配机理）以及再悬浮-重金属释放的动力学过程、沉积物悬浮-重金属释放复合预测模型的建立、沉积物悬浮-释放重金属的生物可利用性及生物毒害评价将是本领域需要进一步研究的重点。

Perspectives on the release of heavy metals via sediment resuspension

Transport and transformation of heavy metals across the water-sediment interface is significant to water quality.In an aquatic ecosystem,sediment-bound heavy metals may be released into the overlying water via sediment resuspension,driven by natural,biological or anthropogenic disturbances.While exogenous inputs of heavy metals are mandatorily reduced by efficient en-vironmental management,endogenous sources of heavy metals released from sediment resuspension can have a major impact on surface water quality and aquatic organisms.This review of studies from the past decade summarizes the driving forces and occur-rences of sediment resuspension,release mechanisms of heavy metals via sediment resuspension,and possible influencing factors.When disturbance exceeds the critical shearing force,sediment resuspension occurs and increases with the disturbance.Organi-cally-bound and sulfide-bound heavy metals suspend into oxic overlying water and are released via oxidation reactions of organic matter and sulfide,while heavy metals adsorbed by sediment particles are released via desorption.Factors,including shearing force,overlying water and sediment physiochemical properties,and microbial activity in sediment,affect heavy metal releases during sediment resuspension.We propose that future studies should improve our understanding of the dynamics and fate of heavy metals from resuspension-release and their toxicity to exposed aquatic organisms.Furthermore,process-based modeling of heavy metals in frequently-resuspended waters is needed for understanding these resuspension-release processes.