汞在SPAC-人体系统中的转递及主要影响因素

汞（Hg）是环境中一种具有高度毒性的重金属元素，且具有较高挥发性，因而作为一种全球性的污染物而备受关注。汞在SPAC系统中的迁移转化，是全球汞循环的重要环节，与人类的建康密切相关。汞通过食物链进入人体并在体内蓄积受多种因素影响，主要包括3个方面：土壤性质（如土壤汞含量、pH、有机质、粘土矿物等），植物特性（植物类型、种类和生育期等），大气状况（如光照强度、气温和大气湿度等）。此外，锌、硒和抗氧化剂等的存在也有较大影响。综述了汞在SPAC-人体系统中的迁移积累及其调控机理。

Transfer of mercury through soil-plant-atmosphere-human continuum and influence factors

Soil-plant-atmosphere-continuum(SPAC) tends to be regarded as system applied to the dynamics of soil water circulation.Based on the fact that mercury(Hg) is a liquid metal at ambient temperatures and pressures and some forms of mercury give rise to a vapor,the process of mercury transfer in SPAC also can be analyzed and discussed similar to soil water.Mercury(Hg)is non-essential for plants and animals and is known as one of the five most toxic environment pollutants.It can be absorbed readily by crops and accumulated in human body through food chains.Mercury pollution has been widely recognized as a global environmental problem because of its volatility and toxicity.The fate and behavior of Hg in soil-plant-atmosphere continuum,which influences human health,is an important link of Hg global cycle.Over the past several decades,the accumulation and transport of Hg in aquatic ecosystems have been extensively and intensively studied.however,there was not substantial interest in the potential transfer of Hg contaminants in terrestrial ecosystem until 1990s,largely stemming from the recognition of the significance of dietary exposure as a major route for metal bioaccumulation in human beings.Food chain is a key pathway,through which Hg in the environment enters human beings(especially in liver,kidney,brain,and muscle) and affects human health.Accumulation of Hg in the bodies of human beings causes renal dysfunction and other diseases,which has been reported in many countries,including Japan and China.There are many factors influencing Hg transfer through food chain to human beings.They mainly include:(1) the availability of Hg in soils,including total Hg,soil clay and organic matter contents,pH,etc.;(2) plant characteristics such as plant species,genotypes and stages of growth and development,etc.;and(3) climate conditions:rainfall,light intensity,temperature,and humidity.The objective of this review is to summarize and update the current understanding of recent advancements in research on Hg transfer and the major factors that influence the transfer of Hg in the soil-plant-atmosphere-human being continuum.Special attention is paid to the kinetics,mechanisms and implications of the reactions interconverting Hg.Finally,future research needs to better understand the transformations of mercury are recommended.