作为一种全球污染物,汞在水体、底泥、土壤、大气等介质中以各种不同形态存在.各种汞形态具有不同的理化特性及毒性.汞形态的转化对于汞的迁移、毒性、食物链富集放大效应等具有重要影响.光照在汞的形态转化中起着重要作用,主要涉及光氧化、光还原、甲基汞的光降解以及无机汞的光化学甲基化等四个方面.本文对不同环境介质中汞的光化学转化过程研究进展进行了总结,并提出了以后研究重点的建议.
As an important global pollutant,mercury presents in various environmental media in different species,mainly as Hg2+,Hg0,and monomethylmercury.Speciation of mercury plays an important role in not only exposure,toxicity and accumulation of mercury to organisms,but also the fate,transport,and cycling of mercury in the environment.The transformation of mercury is greatly determined by biotic and abiotic environmental factors.Photo-induced transformations were recently recognized as important processes in environmental chemistry of mercury,including reduction of Hg2+,oxidation of Hg0,methylation,and degradation of monomethylmercury.The research progress on the environmental photo-chemistry of mercury is reviewed and future prospects in this field are discussed.Also highlighted in this review is the mercury isotope mass-independent fractionation,which could become a powerful tool in the study of mercury photo-transformation.