作　　者： ; ;

机构地区： 贵州师范学院

出　　处： 《中国环境科学》 2016年第9期2730-2740,共11页

摘　　要： 用连续提取方法分析了黄壤中总硫、SO_4^(2-)、总还原态硫(TRS)和有机硫的硫同位素组成,探讨黄壤中硫的迁移转化过程及其环境效应.有机硫是主要的硫形态,SO_4^(2-)是主要的无机硫形态.TRS具有最低的δ^(34)S值,同时SO_4^(2-)和TRS的δ^(34)S值随剖面加深而平行地增大指示黄壤中存在SO_4^(2-)异化还原过程.黄壤剖面中总硫和有机硫的δ^(34)S值先增大后降低与有机硫矿化及有机硫组分的迁移和底层吸附有关.生物滞留后剩余SO_4^(2-)的吸附、解吸、淋溶迁移及深层吸附与累积导致剖面中SO_4^(2-)的δ^(34)S值先增大后明显降低.酸沉降下剖面中SO_4^(2-)的吸附、解吸和淋溶迁移可引起黄壤酸化.值得关注的是,酸沉降输入的SO_4^(2-)主要以有机硫和吸附态SO_4^(2-)滞留在黄壤中,则在硫的年沉降速率大幅降低后,在较长时期内,黄壤中有机硫矿化和吸附态SO_4^(2-)解吸可能释放大量SO_4^(2-)进入地表和地下水体,与之相关的土壤理化性质变化和水体化学组成改变等方面的环境效应值得关注. Sequential extraction method for soil sulfur was used to determine δ34S values of total sulfur, SO42-, totalreduced sulfur (TRS) and organic sulfur in yellow soil, aiming to discuss the transportation and transformation of sulfurand its environmental processes and effects in yellow soil. Organic sulfur was the major sulfur form in yellow soil. SO42-was the major inorganic sulfur form in yellow soil. Total reduced sulfur (TRS) had the lowest δ34S values; meanwhile theparallel increasing δ34S values of TRS and SO42- indicated the occurrence of a bacterial reduction process of sulfate inyellow soil. The δ34S values of total sulfur and organic sulfur firstly increased and then decreased with deepening of soilprofiles, which can be explained by mineralization of organic sulfur and the subsequent transportation and adsorption atbottom layers of organic sulfur fractions in yellow soil profiles. The residual SO42- after biological S retention was firstlyadsorbed and then desorbed; this desorbed SO42- can transport downward and was subsequently re-adsorbed andaccumulated at deep soil layers. This explained the increasing δ34S values of SO42- from surface layers to middle layersand the decreasing δ34S values of SO42- from middle layers to bottom layers in yellow soil profiles. Under acid deposition,the adsorption, desorption and transportation of SO42- can result in soil acidification of yellow soil. It is noted that thedeposited SO42- was retained as organic sulfur and adsorbed SO42- in yellow soil, then yellow soil may release more S intorivers by organic sulfur mineralization and desorption of the adsorbed SO42- in a long period after a large decrease inannual sulfur deposition rate. The environmental implications such as changes of soil properties and chemicalcompositions of river water in southwest China should be investigated in the future.

关 键 词： 喀斯特小流域 黄壤 硫同位素 环境过程和效应