大安灌区农业活动影响下的地下水水质评价及健康风险研究

发布时间：2018-01-01 16:27

本文关键词：大安灌区农业活动影响下的地下水水质评价及健康风险研究　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：大安灌区位于吉林省西部大安市东半部,属于半干旱半湿润大陆季风气候区。其蕴藏丰富石油、天然气、地下水资源,是我国重要的农牧业基地。该区存在土壤盐碱化、荒漠化等问题,为解决该问题,吉林省政府于2007年拟定引嫩江水建立大安灌区规划,改变部分旱地为水田。随着旱改水的进行,起到一定的经济效果,然而由于该区存在蒸发强烈的气候特征,灌区运行时抬高地下水位,形成了大面积的盐碱土沉积,而且该区旱改水后,通过增加施肥量以获取高产,因此,加大了地下水污染的危险。针对以上由土地利用变化引起的地下水水质变差等诸多问题,本文进行研究,确定大安灌区农业活动条件下影响地下水的主要因素。本文简述了大安灌区自然地理、地形地貌、水文地质条件。采用SPSS软件进行三层地下水水化学因子的相关性进行分析,应用Mapgis专业制图软件以及Aquachem软件制作piper三线图、schoeller图、Gibbs图、箱图以及等值线图,据此分析地下水水化学成因、类型及其基本特征;运用数理统计方法分析大安灌区“三氮”存在形式、分布及影响因素;通过地下水测试数据分析大安灌区地下水水质等级,确定影响地下水水质等级变化的原因。在此基础上,对灌区潜水中NO3-与NH4+进行健康风险评价。研究结论表征:(1)大安灌区三层地下水中均以Na-HCO3型水为主,并伴随有Ca、Mg、Cl离子零星组合的水化学类型。三层地下水由浅入深TDS逐渐变小,pH值变化不大。三层水的水化学作用主要以溶滤作用为主,第四系潜水中伴随有蒸发浓缩作用,阳离子交替吸附作用主要发生在地下水由上至下越流补给过程。(2)灌区地下水中“三氮”整体含量显示,NO3-远高于NO2-和NH4+;水平方向上,第四系潜水中NO3-分布广泛,NO2-规律性不强,NH4+主要分布在灌区的施肥作业区,竖直方向上,NO3-与NH4+含量在地下水埋深3-5米处,含量达到峰值;第四系潜水中各离子与“三氮”的相关性均未超过0.5,其中NO3-与HCO3-的相关性最大,NO2-与耗氧量的相关性最大,NH4+与Mn的相关性最大。(3)水质评价结果显示,由上至下各指标评价结果总体上呈现变好的趋势,三层水采样点水质均以Ⅳ类水为主,伴随出现Ⅲ类水、Ⅴ类水,导致第四系潜水水质等级现状的主要因子为原生环境下的Fe、Mn、F-、As等,以及农业活动产生的“三氮”;影响第四系承压水与新近系承压水水质因素主要为Fe、Mn、F-、As。(4)健康风险评价中,NH4+的高风险区占总研究区面积的80%左右,主要分布在研究区东部、中部、北部的大部分地区。
[Abstract]:Daan District is located at the west of Jilin province Da'an City East half, belongs to semi arid and semi humid continental monsoon climate zone. Its rich in oil, natural gas, groundwater resources, is an important agricultural base in China. The area of soil salinization, desertification and other issues, in order to solve this problem, the government of Jilin province in 2007 to establish Nenjiang River Daan irrigation planning, upland paddy field. With the change of cropping system, have certain economic effect, however, due to the presence of strong evaporation climate characteristics of the area, irrigation operation elevation groundwater level, forming a large area of saline alkali soil deposition, and the measured area, through the increase the amount of fertilizer to obtain high yield, therefore, increase the risk of groundwater pollution. The groundwater quality by land use change caused many problems such as variable, this paper determined, Daan irrigation agricultural activities The main factors affecting the groundwater conditions. This paper describes Daan irrigation natural geography, topography, hydrological and geological conditions. The relationship between water chemical factor three groundwater by using the SPSS software to carry on the analysis, three production line graph, Piper Mapgis professional graphics software and Aquachem software Schoeller map, Gibbs map, contour map and map box analysis of groundwater chemical causes, accordingly, types and basic characteristics; using the method of mathematical statistics analysis of Da'an irrigation district "three nitrogen" form, distribution and influencing factors of groundwater; through the test data analysis of Da'an Irrigation District groundwater quality, groundwater level changes determine the cause effect. Based on this, the health risk assessment of NO3- and NH4+ irrigation diving. Conclusion characterization: (1) three layer of groundwater in Da'an Irrigation District in Na-HCO3 water mainly with Ca, Mg, Cl ions Hydrochemical types of sporadic combinations. Three layers of groundwater from the shallower to the deeper TDS became smaller and pH value had little change. The water chemistry of three layer water mainly by leaching, accompanied by Quaternary phreatic evaporation, cation exchange adsorption mainly occurs in groundwater from top to bottom leakage process (2). The underground water irrigation area of "three nitrogen" overall showed that the content of NO3- is much higher than that of NO2- and NH4+; the horizontal direction, the Quaternary diving NO3- are widely distributed, NO2- law is not strong, NH4+ is mainly distributed in the area of irrigation fertilization, vertical direction, NO3- and NH4+ content in the groundwater depth of 3-5 meters, the content reached the peak the correlation of the ionic quaternary phreatic water; and "three nitrogen" were not more than 0.5, the correlation between NO3- and HCO3-, NO2- and the correlation between oxygen consumption, NH4+ and Mn (3). The correlation between the water quality evaluation results show that by The overall evaluation results of each index to the good trend, three water quality sampling points to IV water, with the emergence of class III water, V water, main factor lead to the present situation of phreatic water quality grade for the Quaternary native environment of Fe, Mn, F-, As, and agricultural industry the "three nitrogen"; influence of confined water and Neogene quaternary confined water quality factors are mainly Fe, Mn, F-, As. (4) in health risk assessment, the high risk region of NH4+ accounted for about 80% of total area, mainly distributed in the study area in the Middle East, mostly in the north.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S273.4

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