陕西省不同生态类型区河流水质时空变化及其评价

发布时间：2018-04-28 08:59

  本文选题：河流水质 + 评价　； 参考：《中国科学院教育部水土保持与生态环境研究中心》2017年博士论文

【摘要】：陕西省位于内陆腹地,由北至南横跨干旱半干旱区、半湿润区、湿润区,境内有黄河、长江穿境而过。以北山和秦岭为界,陕西省自北向南可以分为陕北,关中和陕南三大自然区域。为较全面真实的反映该省省地表水水质状况,选取不同生态类型区的3条主要河流(渭河、延河和汉江)为研究对象,依据河流27断面水质监测资料,参照地面水环境质量标准(GB3838-2002),从溶解氧(DO)、高锰酸盐指数(COD_(MN))、生化需氧量(BOD5)、氨氮(NH_3-N)、挥发酚、石油、化学需氧量(COD)等7个评价指标出发,对延河流域5个断面、渭河流域13个断面、汉江流域9个断面的水体污染过程和控制进行了评价,从水体污染的角度出发分析了3条典型河流的污染源,提出系统切合实际的治理对策。取得如下主要结论:(1)典型河流水体水质呈现明显的时空变化特征。2001-2010年间,3条典型河流水质改善明显,27个监测断面中满足I~Ⅲ类水质水体功能的断面由11个增加到18个,达标断面率为66.7%,Ⅴ类水质断面9个,占33.0%。在空间尺度上,3条典型河流水质污染呈现较大的南北空间差异,位于秦岭以北的渭河干流污染严重,属重度污染,延河属轻度污染;位于秦岭以南的汉江水质十年均评价为优。(2)典型河流水体污染主要以有机型污染主。渭河流域石油类、NH_3-N、BOD5、DO、COD_(MN)浓度降低明显,延河流域COD、石油类污染因子污染浓度降低明显,汉江流域主要以NH_3-N污染为主,并呈现减低趋势。(3)典型河流水体污染程度与河流径流量密切相关。渭河DO浓度与径流量呈现正相关关系。延河流域BOD5浓度与年径流量呈显著负相关;输沙量与挥发酚浓度呈正相关趋势NH_3-N浓度与年径流量显著负相关。汉江径流与COD_(MN)浓度浓度呈负相关趋势,但相关性指数不明显,年输沙量和COD_(MN)浓度呈显著正相关,输沙量量越大,COD_(MN)越高,水质污染越严重。(4)陕西省不同区域典型河流水体污染呈现不同特征,陕南的汉江流域水体污染物主要来源于农业面源污染,因此进一步改善该流域农业种植模式与结构,控制化肥用量是提升汉江水质的主要措施;位于关中地区的渭河,污染物较为复杂多样,一方面需要控制该流域农业种植过程中化肥用量,另一方面需控制区域内城市各类污水的排放;位于陕北的延河流域以发展生态农业,防止水土流失是提升水质的有效措施。
[Abstract]:Shaanxi Province is located in the hinterland, from north to south across the arid and semi-arid, sub-humid, humid areas, the territory of the Yellow River, the Yangtze River across the border. From north to south, Shaanxi Province can be divided into three natural regions: northern Shaanxi, Guanzhong and southern Shaanxi. In order to reflect the surface water quality of the province, three main rivers (Weihe River, Yanhe River and Hanjiang River) in different ecological regions were selected as the research objects, and the monitoring data of water quality of river section 27 were used. Referring to the environmental quality standard of surface water (GB3838-2002U), this paper deals with 7 evaluation indexes, such as dissolved oxygen (DOA), permanganate index (CODX), BOD5, NH3-N, volatile phenol, petroleum, chemical oxygen demand (COD), and 13 sections in Weihe river basin, and 5 sections in Yanhe river basin, 13 sections in Weihe river basin, and so on, according to the environmental quality standard GB3838-2002.In this paper, seven evaluation indexes, such as NH3-NU, volatile phenol, petroleum and chemical oxygen demand (COD), are presented. The process and control of water pollution in nine sections of Hanjiang River basin were evaluated. The pollution sources of three typical rivers were analyzed from the point of view of water pollution. The main conclusions are as follows: (1) the water quality of typical rivers shows obvious temporal and spatial variation. During 2001-2010, the water quality of 3 typical rivers has improved obviously, and the number of sections satisfying the functions of I- 鈪，

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