Kim Moon-Kyung, Zoh Kyung-Duk
Department of Environmental Health, Seoul National University School of Public Health, Seoul, Korea.
J Prev Med Public Health. 2012 Nov;45(6):335-43. doi: 10.3961/jpmph.2012.45.6.335. Epub 2012 Nov 29.
Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg(0)) and divalent (Hg(2+)) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg(2+), can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.
汞从各种自然和人为来源排放到大气中，并且在环境中难以降解。汞以多种形态存在，在空气和水中主要取决于其氧化态，主要为元素汞（Hg(0)）和二价汞（Hg(2+)）。排放到大气中的汞可通过湿沉降和干沉降沉积到水环境中，有些还会再次排放到大气中。沉积的汞形态主要是Hg(2+)，可通过硫酸盐还原菌介导的生物反应以及阳光光解介导的非生物反应，与水和沉积物中的各种有机化合物发生反应，从而转化为有机汞，如甲基汞（MeHg）。甲基汞可通过生态系统中的食物网进行生物累积，最终使食用鱼类的人类受到暴露。为了更好地理解人类如何在环境中接触汞，本文综述总结了汞的排放、归宿与迁移、形态化学、生物累积、环境介质中的污染水平以及最终人类暴露评估的机制。
