大河口水库氮污染特征及同位素源解析研究

发布时间：2018-01-04 05:18

本文关键词：大河口水库氮污染特征及同位素源解析研究　出处：《内蒙古农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：我国是人均水资源较为贫乏的国家,自然湖泊和人工水库在经济建设与社会发展中发挥着极其重要的作用。近几十年来,伴随着人口增长和经济的飞速发展,地表水污染日益严重,其中湖泊、水库污染更为严重。本文以地处沙源区大河口水库水体、上游水体、大气干湿沉降及周边典型地块作为研究对象,通过采集样品并测定硝态氮、亚硝态氮、氨态氮、总氮、化学需氧量以及δ15N-N03、δ180-N03等指标,运用SPSS统计分析软件和Arcgis绘图软件,分析水库及上游水体不同形态氮的污染状况和分布特征,应用稳定同位素技术解析大河口水库氮污染主要来源。得出主要结论如下:(1)水库枯水期氮污染化学特征主要以N03-N为主,局部水域浓度可达到1.61mg/L,平水期与丰水期氮污染化学形态主要以TN为主,最大值分别为14.10mg/L、10.52mg/L。受农业面源污染的影响,水库上游河道水体中NH3-N浓度在丰水期浓度最高,最大浓度1.63mg/L。(2)2016年水库上游河流输入TN污染负荷量为21.05t,占TN入库污染负荷总量的72.3%,大气沉降占TN污染负荷总量的27.7%。通过对入库河流径流和大气沉降两种外源氮输入进行污染负荷量估算和贡献率计算。结果表明,上游河流径流TN输入是引起水库氮污染的主要成因。(3)应用稳定同位素技术对入库河流源解析得出,冬季入库河流水体中有81.21%的样品δ15N-NO3与8180-NO3值落入生活污水与人畜粪便特征值域范围内,而在夏季受农业面源及降雨量等多重因素的影响,化学肥料、人畜粪便成为入库河流主要氮污染来源。(4)对水库大气干沉降氮污染源解析研究发现,春、秋、冬季节大气干沉降样品δ15N-N值落入可辨别沙地、耕地特征区间范围占总样本数的40%以上,证明沙地、耕地为水库大气干沉降氮污染的主要来源,结合水库周边土地利用类型以及气候特征等因素,可以判定夏季大气干沉降氮污染主要源于周边沙地。
[Abstract]:China is a country with relatively poor per capita water resources. Natural lakes and artificial reservoirs play an extremely important role in economic construction and social development. In recent decades, population growth and rapid economic development have been accompanied by. Surface water pollution is becoming more and more serious, especially lakes and reservoirs. This paper takes the water body of Dahekou Reservoir, upstream water body, dry and wet deposition of atmosphere and typical land block around as the research object. The samples were collected and the indexes such as nitrate nitrogen, nitrite nitrogen, ammonia nitrogen, total nitrogen, chemical oxygen demand and 未 15N-N03, 未 180-N03 were determined. The pollution status and distribution characteristics of different nitrogen forms in reservoirs and upstream waters were analyzed by using SPSS statistical analysis software and Arcgis drawing software. The main sources of nitrogen pollution in Dahekou reservoir are analyzed by using stable isotope technique. The main conclusions are as follows: (1) the chemical characteristics of nitrogen pollution in the dry season of the reservoir are mainly N03-N. Local water concentration can reach 1.61 mg 路L ~ (-1), nitrogen pollution chemical form is mainly TN in the normal and high water periods, the maximum value is 14.10 mg / L, respectively. Under the influence of agricultural non-point source pollution, the concentration of NH3-N in the upper reaches of the reservoir was the highest in the high water season. In 2016, the input TN pollution load of upstream river was 21.05 t, accounting for 72.3% of the total TN pollution load. Atmospheric deposition accounts for 27.7% of the total TN pollution load. The pollution load and the contribution rate of the two exogenous nitrogen inputs into the reservoir are estimated and calculated. TN input from upstream river runoff is the main cause of nitrogen pollution in reservoirs. In winter, 81.21% samples of 未 15N-NO _ 3 and 8180-no _ 3 fall into the characteristic range of domestic sewage and human and animal faeces. And in summer by agricultural non-point source and rainfall and other factors, chemical fertilizer, human and animal manure become the main source of nitrogen pollution into the reservoir river. In autumn and winter, the 未 15N-N value of atmospheric dry deposition samples fell into discernible sandy land, and the range of cultivated land characteristics accounted for more than 40% of the total samples, which proved that sandy land. Cultivated land is the main source of nitrogen pollution caused by dry deposition of the reservoir. Combined with the types of land use and climatic characteristics around the reservoir, it can be determined that nitrogen pollution of dry deposition of the atmosphere in summer mainly comes from the surrounding sandy land.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X524

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