北京北部水源地水化学特征及硫同位素变化

【作者】 邢鑫；

【导师】 季宏兵；

【作者基本信息】 首都师范大学 ， 环境工程， 2011， 硕士

【摘要】 本文选取北京北部水源地(密云水库库区及其上游两大主要支流潮河、白河)作为研究对象,对照野鸭湖湿地、温榆河和北运河,利用该地区的水化学特征和硫同位素组成的变化来分析河水中溶解质的来源,计算岩石风化对硫元素的相对贡献率,以期反映该地区受自然和人为因素的影响,进而反映北京北部水源地对全球环境变化在一定时期内的响应。本文对研究区分丰水期和枯水期(2009年)进行水化学特征和硫同位素组成变化的分析后,可以得到如下主要结论：1、北京北部水源地水体的主要离子组成中,Ca2+和HCO3-是占绝对优势的离子,分别占阳离子和阴离子总量的52.2%和86.3%,其次是Mg2+和SO42-,分别占阳离子和阴离子总量的23.7%和7.7%。2、北京北部水源地水体主要阴离子和阳离子Piper图和Ca2++Mg2与HCO3-的当量曲线图都显示出北京该地区主离子组成主要受碳酸盐岩化学风化作用影响。3、根据Gibbs图分析,北京北部水源地水体属于“岩石风化类型”,有向“蒸发-浓缩类型”过渡的趋势。该流域离子组成受岩石风化作用的影响十分强烈而受大气降水的输入和蒸发-浓缩作用的影响相对较少。4、根据质量守恒原理,计算出大气输入对本研究区河水主要离子的直接贡献率分别为：Na+的10.63%,K+的46.76%,Mg2+的3.05%,Ca2+的7.76%,SO42-的35.77%。5、研究区丰水期δ34S特征值在4.9～10.7‰之间,平均值为7.9‰,其中密云水库库区及潮河、白河的δ34S特征值平均值分别为8.7‰、6.0‰、8.2‰,库区的δ34S特征值最高,潮河干流的δ34S特征值最小。根据质量守恒原理,计算出硫元素来源于硫酸盐岩的溶解比例为30.72%～42.47%；来源于硫化物氧化的比例为21.74%～33.49%；来源于大气输入的为35.77%。更多还原

【Abstract】 In this paper we choose the water source area (Miyun Reservoir and its two tributary rivers of Chao River and Bai River) of northern Beijing as the research object,controlled with Yeyahu Lake Wetland,Wenyuhe River and Beiyunhe River,according to the hydro-chemistry characteristics of the research area and changes of sulfur isotopic composition characteristic values,we analyze the dissolved load sources, then calculate the rocks weathering and the relative contribution to sulfur, in order to reflect natural and regional effects on the research area, furtherly, to explain Miyun Reservoir’s response to the global environmental change during a certain period of time. For time being of 2009, hydro-chemical and sulfur isotopic characteristics of wet and dry seasons are analysed to draw the conclusions below:1 Ca2+ and HCO3- are the dominant ions in northern Beijing’s water source area, accounting for 52.2% and 86.3% of total cations and anions, following with Mg2+ and SO42- occupying 23.7% and 7.7% respectively.2.Piper diagram of anions and cations and equivalent curves of Ca2+ + Mg+ and HCO3- in the water source area of northern Beijing’s water supply show that primary ions in the region is mainly affected by chemical weathering of carbonate rocks.3.According to Gibbs chart, the surface water in Beijing’s water source area is "the type of rock weathering",it shows a transition trend to turn to "evaporate-concentrated type". Ionic composition of the river basin is effected by the weathering of rocks strongly and on the other hand, the effects of the input by precipitation and evaporation are relatively small.4.According to mass conservation principle, the direct contributions to the major ions in the river from the atmospheric input in the study area are Na+:10.63%;K+:46.76%;Mg2+ 3.05%; Ca2+:7.76%; SO42-:35.77%.5. Values of 834S ranged from 4.9‰to 10.7‰, with an average of 7.9‰in wet period..Average values ofδ34S in the study area,Chao River and Bai River are 8.7‰,6.0‰and 8.2‰,respectively. Miyun Reservoir has the highestδ34S values, while Chao River has the lowestδ34S values.According to the mass conservation principle, we know that 30.72% 42.47% sulfur comes form the sulfate dissolved rock,and 21.74%～33.49% sulfur comes from sulfide oxidation; 35.77% sulfur comes from the atmosphere input.更多还原