环境中的硫化汞及其生物可利用性

Mercuric Sulfide in Environment and Its Bioavailability

硫化汞(HgS)是最常见的汞形态,由于其较低的溶解度,常被认为是生物惰性的,但近些年的研究证明,HgS可被微生物甲基化,生成毒性较强并能在食物链中传递和蓄积的甲基汞(MeHg),对生态安全和人类健康造成潜在威胁。HgS主要存在于汞矿,人类对汞的长期开采利用导致HgS在自然界中也广泛分布,并以多种形式存在。文献证明HgS本身的理化性质以及多种物质和环境因素均可以影响HgS的环境行为,这些环境行为也是汞循环的重要环节。本文总结了HgS的分布、分析方法、生成、转化以及生物可利用性等方面的研究现状,希望能对进一步探究HgS在汞的地球化学循环过程中扮演的角色以及发展汞生态风险的评估技术有所帮助。

Mercuric sulfide(HgS)is one of the most common forms of mercury.It is generally considered biologically-inert due to its low solubility.However,recent studies have demonstrated that HgS can be converted into methylmercury(MeHg)by microorganisms in the soil.MeHg is highly toxic and can accumulate in the food chain,thus threatening ecologies and posing health risks to human beings.HgS is widely distributed in the environment,especially in mercury mines and some specific soils,due to long-term mining and wide utilization of mercury.It is well documented that the environmental behaviors of HgS can be substantially affected by many environmental factors(i.e.,DOM,microbes,pH)and the physicochemical properties of HgS itself,then contributing to global mercury cycling.This paper mainly summarized the research on the formation,distribution,transformation,and bioavailability of HgS,as well as the relative analytical methods.It should be beneficial for further understanding the role of HgS in global mercury cycling and give clues for scientific assessment of mercury toxicity in croplands and food chains.