【作者】 廖梦霞；

【导师】 汪??邓天龙；

【作者基本信息】 成都理工大学 ， 地球化学， 2005， 博士

【摘要】 环境污染问题是二十一世纪全球面临的重大问题之一。我国湖泊众多,以鄱阳湖最具代表性,是我国最大的淡水湖。在国家自然科学基金项目（编号:40103009）、教育部优秀青年教师基金项目（编号:20011766）联合资助下,以鄱阳湖为研究对象,首次开展了不同季节鄱阳湖沉积物——水界面砷、锑的环境地球化学行为研究。 主要研究内容:①建立痕量、超痕量元素砷的形态的高灵敏连续蠕动式氢化物原子荧光光谱分析方法;②不同季节鄱阳湖康山、瑞洪、湖口三地间隙水中As（Ⅲ）、As（Ⅴ）、As-org、Sb（Ⅲ）、Sb（Ⅴ）、Sb-org及Fe²⁺、Mn²⁺、S^2-、pH、总有机碳（TOC）的垂向分布;③不同季节三地沉积物中砷、锑总量（TAs,TSb）、吸附在Fe、Mn氧化物的砷、锑（As-oxal,Sb-oxal）、与有机物结合的砷锑（As-H₂O₂,Sb-H₂O₂）、吸附在硫化矿物上的砷锑（As-pyrite,Sb-pyrite）的相应浸提和垂向分布;④不同季节三地沉积物中总铁（TFe）、总锰（TMn）、Fe-oxal、Mn-oxal、Fe-H₂O₂、Mn-H₂O₂的垂向分布;⑤不同季节三地沉积物中总硫（TRS）、酸可挥发性硫（AVS）、黄铁矿中的硫（PS）、元素硫（ES）的垂向分布。 主要研究成果:①首次发现 8-羟基喹啉对五价砷具选择性掩蔽,并同时可消除共存离子对测定的干扰,成功地建立了砷[As（Ⅲ）、As（Ⅴ）、As-org]形态分析方法,具有砷赋存形态分析的分析地球化学方法创新性:②沉积物中砷主要以铁锰氧化物和硫化矿物结合为主,其迁移、循环受铁锰氧化还原电位、生物活动和硫的屏蔽作用等因素的控制,呈现沉积—溶解—扩散—再沉积特征,具有地球化学指示意义;③鄱阳湖间隙水中各形态砷的含量较高,沉积物环境变化,极易造成砷的二次污染;④鄱阳湖间隙水锑的各形态含量虽相对较低,其季节性特征仍显著,沉积物中锑受铁锰化合物、硫化矿物控制,但其迁移循环影响因素较复杂;⑤关于我国长江中下游湖泊沉积物——水界面痕量、超痕量元素砷、锑的赋存状态及其环境地球化学研究,目前国内外尚未见报导,本研究可填补相应空白,有力地推动了在水——沉积物界面砷、锑的环境地球化学新认识。更多还原

【Abstract】 Environmental pollution is one of vertical problems faced in 21 century. There are amounts of lakes located in China. Poyang Lake, which is the largest freshwater lake in China is the famous representation. Through the financial supports from The National Natural Science Foundation of China （Grant 20011766）, The Excellent Young Teachers Program of MOE, P R China （Grant 40103009） respectively, the environmental geochemistry on trace and ultra-trace elements of As and Sb in the sediment-water interface （SWI） of Poyang Lake was investigated into details.The researched contents are including: （1）a sensitive speciation analysis method was established to measure the trace and ultra-trace elements of arsenic in porewater samples of sediments; （2） vertical profiles on As（III）, As（V）, As-org, Sb（III）, Sb （V）, Sb-org and dissolved ions of iron, manganese, S2- and pH value, total organic carbon （TOC） in the series porewater samples in the areas of Kangshan, Ruihong and Hukou, Poyang Lake, China were measured; （3）total arsenic, total antimony （expressed as TAs, TSb） in sediments, arsenic and antimony absorbed onto oxyhydroxides of iron and manganese （expressed as As-oxal, Sb-oxal）, associated to organic matters （expressed as AS-H2O2, Sb-H2O₂）, and arsenic and antimony existed in the crystallized sulfides （expressed as As-pyrite, Sb-pyrite） in different seasons respectively were extracted by a sequential extracted procedures, and then were analyzed; （4）vertical distributions on TFe, TMn, Fe-oxal, Mn-oxaLFe-H2O2, Mn-H2O2 respectively were also done; （5）total sulfur, acid volatile sulfur, minerals of sulfide and elemental sulfur in sediment samples in the different seasons were extracted and analyzed.Solutions presented in the project can be summarized as follows: it is the first time to discover that the masking agent of 8-hydroxyquinoline was found to be an efficient agent to eliminate interference of transition metals in the determination of arsenic species, especially to eliminate As（V） emission with high selection in the matrix of As（III） and As（V） coexisted solution. A sensitive and interference-free procedure has been successfully established for the arsenic speciation on As（III）, As（V）, As-org in porewater samples using flowing injection hydride generation atomic fluorescence spectrometry （FI-HG-AFS）.We observed that the concentrations of arsenic species in porewaters were relatively high. With the change of the redox in sediments, it is easy to arose the second pollution in overlying waters for their diffusive upward. Arsenic is mainly absorbed onto iron and manganese oxyhydroxides in controlling the behavior of As. The effect factors of the transfer, cycle of arsenic are the redox condition at SWI, disturbance, and microbial action, etc. Arsenic has a directive signification of geochemistry characteristic in SWI because arsenic species are concentrated near the SWI and involved in a dynamic cycle with precipitation - dissolution - diffusion -reprecipitation of iron and manganese oxyhydroxides. Antimony was controlled by several factors and compounds, mainly with the dissolution of sulfide, sulfur complexation and microbials. Although the concentrations of Sb species were relatively much lower than arsenic, the seasonal changes are distinctness. The concentrations of inorganic and organic antimony were fearfully low because it is mainly controlled by sulfides in sediments. Although some new knowledge on geochemical behavior of antimony was achieved on the bases of antimony speciation analysis proposed in this supported projest, some uncertainties are still exised due to the effect factors are very complex located in SWI. The process and mechanism on antimony transfer and transport in SWI need to be further studied.更多还原