中文摘要：

硒是一种对环境具有灵敏指示意义的元素，在表生环境中存在诸多形态，如 Se （Ⅳ）, Se （Ⅵ）, Se （0）, Se （-Ⅱ）、Org-Se，每种形态都有独特的化学、生物化学性质（控制元素的可溶性、毒性、营养功能、环境行为）．在综合分析近年来国内外表生环境硒形态研究的基础上，作者分别对岩石（矿物）、土壤和沉积物、生物体、各种水体、大气中硒自然形态的分布进行了综述，并初步建立了不同体系之间硒在积累、迁移过程中形态迁移转化的地球化学模型；最后指出了硒形态研究方面有可能的前景．

英文摘要：

Selenium is one of the elements that are sensitive to environmental change. There are some species of selenium in nature, such as Se （Ⅳ）, Se （Ⅵ）, Se （0）, Se （-Ⅱ） and Org-Se. Every species of selenium has different chemical and biochemical characteristics （solubility, toxicity, the function of nutrition, environmental behavior, etc.）. The authors analyzed synthetically the speciation of selenium in the supergene environment at home and abroad. On this basis, the distribution of selenium species in different systems （rock, soil, sediment, water, biomass） was described synthetically. Then, a primary geochemical model of transformation of selenium species was established for the supergene environment. The authors pointed out the prospective of research on selenium speciation.