桂林甑皮岩遗址地下水水化学特征及成因分析

发布时间：2018-01-27 03:32

本文关键词： 甑皮岩地下水污染水化学硫氧同位素　出处：《西南大学》2017年硕士论文　论文类型：学位论文

【摘要】：地下水作为水资源的一个重要组成部分,其分布广泛,储量丰富,水质良好,便于开采,被作为世界上普遍的饮用水供水水源。地下水不仅可以作为居民的生活供水水源,同时也是工农业的主要供水来源,因此,地下水对经济的发展以及人类生产生活至关重要。但是人类长期关注经济发展而忽视了环境保护,地下水的水质不断受到人类生产生活所带来挑战,居民用水常常受到威胁。而岩溶系统作为一种脆弱的陆地生态系统,其发育广泛,由于岩溶区特殊的地表、地下双层结构,土壤层稀薄,造成基岩的大片裸露,由于缺少土壤的防护作用,各种地表和大气污染物通过落水洞、竖井、漏斗、塌陷和溶蚀裂痕等通道进入岩溶地下水系统。岩溶地区受岩溶环境的制约,不当的土地利用会使岩溶环境失衡,其中岩溶地下水水化学组分的变化以及污染就是最为严重的环境问题之一。水污染导致的水质恶化等方面水质安全问题已经严重影响着人民的生活质量和社会经济的发展。其中结合硫氧同位素示踪地下水中硫酸盐的污染来源,提高结果的科学性。可以解决单一δ34SSO_4结果中值域的重叠现象。本文以甑皮岩及其附近地下水区域为研究对象,将硫氧同位素与传统水化学方法相结合,分析地下水的物质组成以及地下水水化学的时空变化趋势,分析研究区地下水中SO_4~(2-)等污染物的降解,吸收,吸附作用规律以及污染物的持久性。根据硫同位素数据结果分析研究区硫污染来源。通过数据分析得出如下结论:甑皮岩地区地下水水化学类型主要为HCO3-Ca和HCO3-Ca+Mg型,在不同月份和不同采样点还表现为HCO3+SO_4-Ca+Mg,HCO3+SO_4-Ca型,2014年HCO3+SO_4-Ca+Mg型水较多,Ca2+、Mg2+、HCO3-主要来自于甑皮岩主要含水岩组融县组灰岩及桂林组白云质灰岩,这三种离子与岩溶作用联系紧密。其水化学特征反映了碳酸盐岩的风化溶解主要控制着区域地下水的物质组成,同时,相对偏高的SO_4~(2-)反映出地下水可能受到人类活动的影响。受季风性气候的影响,降雨集中,地下水中各离子浓度雨季降低,旱季增大,与冬季相比,夏季各离子受到不同程度的稀释作用。由于岩溶介质的非均质性和岩溶水的高度敏感性,岩溶水的水动力条件以及地球化学环境的不同,也就会形成水化学曲线的差异,主要表现为稀释效应和污染物淋滤效应。污染物持久效应可以通过衰减率和衰减速率来表现。阳离子中Na+的衰减率最大,K+的含量在溶洞水和管道水中主要呈现上涨趋势,衰减率大多为20%~35%,只有在Y3呈现衰减。Ca2+和Mg+无明显规律。阴离子中Cl-衰减率较大,多为20%~60%,裂隙水SO_4~(2-)和NO3-的衰减率波动范围大于管道水,溶洞水与管道水中SO_4~(2-)的衰减率很低并且部分为正,裂隙水中各采样点的变化幅度较大。除zk14出现增长外,NO3-在溶洞水和管道水的衰减率相似,为20%~30%,裂隙水的衰减率相比溶洞水和管道水略微偏高。研究区地下水主径流带衰减速率在各段以及丰水期和枯水期各不相同,阳离子中Ca2+的衰减速率最快,K+的速率最慢,阴离子中SO_4~(2-)变化速率较大在丰水期,SO_4~(2-)主要表现为从上游到下游为负的衰减速率,在枯水期则表现为从上游到下游正的衰减速率。甑皮岩地区附近地下水的δ~(34)SSO_4值的变化范围在-4.14~8.13‰之间,均值为-0.91‰,除了zk10显著偏正外,其它采样点分布较为集中,δ18OSO_4值的变化范围在-3.25~9.74‰之间,除了zk10,zk16,y1这三个点之外,其它采样点分布比较集中,将研究区硫酸盐主要可能来源端元进行投影,可以看出,甑皮岩地区地下水和地表水的硫氧同位素组成相对集中在大气降水和无机硫氧化产物之间,这与之间的判断较为相符,说明甑皮岩地区地下水硫酸盐来自于大气降水、煤渣的共同贡献。
[Abstract]:Groundwater is an important part of water resources, which are widely distributed, rich reserves, good quality, easy to mine, known as the world's common drinking water. Groundwater can not only be used as living water supply of residents, the main source of water supply, but also the industry and agriculture therefore, groundwater on economic development and human production life is very important. But the human long-term focus on economic development while ignoring environmental protection, groundwater quality has been the production of human life brought challenges, the residents of water are often threatened. And the karst system as a fragile terrestrial ecosystem, which developed widely, because the surface of karst area, underground double structure, thin soil layer a large, exposed bedrock, due to lack of protective effect of soil, surface and air pollutants through sinkholes, shaft, collapse and funnel. Corrosion cracks and other channel into the karst groundwater system. Karst area is restricted by the karst environment, improper land use will make the karst environment imbalance, which changes the karst groundwater water chemical component and pollution is one of the most serious environmental problems. The water quality deterioration of water quality safety problems caused by water pollution has seriously affected the development of the quality of people's life and social economy. The combined pollution sources of sulfate sulfur oxygen isotope tracer in groundwater, improve scientific results. Can solve the single Delta 34SSO_4 results in the range overlap phenomenon. This paper takes the zhenpiyan groundwater and its nearby region as the research object, combining the traditional sulfur oxygen isotope and water chemistry method for analysis of groundwater composition and temporal spatial variation of groundwater chemical trend analysis SO_4~ ingroundwater (2-) and other pollutants reduction The solution, absorption, adsorption law and persistent pollutants. According to sources of sulfur pollution in the study area of sulfur isotope data. Through data analysis, draws the following conclusion: groundwater zhenpiyan area is mainly HCO3-Ca and HCO3-Ca+Mg, in different months and different sampling points are shown as HCO3+SO_4-Ca+Mg, HCO3+SO_4-Ca, HCO3+SO_4-Ca+Mg in 2014 water more, Ca2+, Mg2+, HCO3- mainly come from the zhenpiyan main aquifer Rongxian formation limestone and dolomitic limestone Guilin group, the three kinds of ions and karst closely. The hydrochemical characteristics reflect the carbonate rock weathering dissolution mainly control the regional groundwater composition, at the same time and the relatively high SO_4~ (2-) reflects the groundwater may be affected by human activities. Affected by the monsoon climate, rainfall, rainy season the ion concentration in groundwater decreased drought Ji Zengda, compared with the winter, summer is the ion dilution effect in different degree. Because of high sensitivity and heterogeneity of karst water in Karst medium, the hydrodynamic condition of karst water and different geochemical environments, the difference will also form a water chemistry curve, the main performance for the dilution effect and leaching effect of pollutants pollutants lasting. Effect can be achieved by the decay rate and decay rate. Cation decay rate of Na+, the content of K+ in karst water and water pipe are showing a rising trend, the decay rate is 20%~35%, only.Ca2+ and Mg+ attenuation at Y3 showed no obvious regularity. The anion decay rate of Cl- is large, multi 20%~60%, fissure water SO_4~ (2-) decay rate fluctuation range is more than NO3- and water pipes, water pipes and karst water SO_4~ (2-) the attenuation rate is very low and is positive, the fissure water sampling point change amplitude In addition to a greater degree. ZK14 growth, NO3- in karst water and water pipeline decay rate is similar to that of 20%~30%, the decay rate of fissure water and karst water pipe water compared to slightly higher. The groundwater Main Runoff zone decay rate in each section and the wet and dry seasons are different, Ca2+ cation in the fastest decay rate, the rate of K+ is the slowest, the SO_4~ ion (2-) change rate was larger in the wet season, SO_4~ (2-) is mainly from upstream to downstream for the decay rate of negative, in the dry season is from upstream to downstream is the decay rate of groundwater near the zhenpiyan area 8 ~ (34) SSO_4 values were in the range of -4.14~8.13%, average -0.91%, except zk10 significantly biased, the other sampling points distribution is more concentrated, the variation range of 18OSO_4 values at -3.25~9.74% between, in addition to zk10, zk16, Y1 these three points, the other sampling points distribution The study area is relatively concentrated, the main source of sulfate may element projection, can be seen that the sulfur isotope zhenpiyan area of groundwater and surface water composition is relatively concentrated in atmospheric precipitation and inorganic sulfur oxidation products, and this is consistent with the judgment between groundwater, sulfate zhenpiyan area from atmospheric precipitation, CO the contribution of the cinder.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P641.3;X523

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