摘要
为了预防和控制流域地表水氮污染,以渭河流域关中段作为研究对象,运用水化学和氮同位素方法研究地表水硝酸盐氮(NO3^--N)污染特征,揭示地表水NO3^--N的主要来源。结果表明,地表水NO3^--N质量浓度为1.3~35.7 mg/L,平均质量浓度为8.6 mg/L,与GB 5749-2006《生活饮用水卫生标准》中规定的硝酸盐氮限值相比,超标率为32.4%,超标样品中δ15N值在+8.3‰^+27.0‰。地表水NO3^--N污染存在明显的空间异质性特征,干流污染大于支流,干流中宝鸡段、渭南段及支流中千河、北洛河、石头河、罗纹河NO3^--N污染较为严重。渭河流域关中段NO3^--N污染受人为活动的影响显著,各条河流沿途接纳来自各城市的生活污水。干流上游NO3^--N污染来源主要为工业污水;下游咸阳段、西安段、渭南段等地区地表水NO3^--N污染来源转变为以粪便和生活污水为主。
Collected surface water samples from Guanzhong area,Shaanxi,in the Weihe River Basin so as to prevent and control the nitrate nitrogen(NO3^--N) pollution of the surface water in the watershed.For this purpose,we have done the hydrochemical assessment and nitrogen isotopic measurement to determine the pollution levels of nitrate by identifying its main pollution sources on the water surface.The results of our assessment indicate that the NO3^--N concentration in the surface water ranges from 1.3 mg/L to 35.7 mg/L,with the mean value of 8.6 mg/L.Actually,about 32.4% of the surface water samples has been found NO3^--N(10 mg/L),which is above the drinking water standard(GB 5749-2006).For example,the average NO3^--N concentration rate of the northern and southern tributaries of the main stream of the River have been found equal to 10.5 mg/L,7.9 mg/L and 7.7 mg/L,respectively,that is,about 70%,16.6%,16.6% of the surface water samples from the above mentioned two tributaries of the river.What is more,from the point view of the spatial distribution of nitrate nitrogen distribution in the basin,the nitrate nitrogen concentration rates in the different regions of the river reach vary greatly.For instance,the said rates in the main stream of Weihe River have been discovered obviously much higher than those in its tributaries.The actual nitrate nitrogen pollution in Weihe River main stream in Baoji section and Weinan section,Qianhe River,Beiluo River,Shitou River and Luowen River have been found more serious than that in other counterparts.For instance,the constituent composition rates of the nitrogen isotope value turn to range from + 8.3‰ to+ 27.0‰,with the mean percentage of 13.0‰,though not any significant effect of denitrification has been detected on the shift in the nitrogen isotopic values in the surface water.Thus,the results of hydrochemistry and nitrogen isotopic composition indicate that the nitrate nitrogen pollution in the Weihe River Basin ought to have been significantly affected by the human activities,for the river system has received large amounts of municipal sewage in its water current covering directions.Specifically speaking,the main source of the nitrate nitrogen pollution in Baoji section of Weihe River stream belongs to the industrial sewage,whereas that in Xianyang section,Xi'an section and Weinan section should be categorized mainly into the agro-manure and domestic sewage.
作者
张妍
张鑫
毕直磊
李楠
ZHANG Yan;ZHANG Xin;BI Zhi-lei;LI Nan(Shaanxi Key Laboratory of Earth Surface System Environmental Carrying Capacity,College of Urban and Environmental Sciences, Northwest University,Xi'an 710127,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2018年第6期2395-2400,共6页
Journal of Safety and Environment
基金
国家自然科学基金项目(41601017)
中国博士后基金项目(2015M572591)
陕西省自然科学基础研究项目(2017JQ4001,2018JQ5151)
关键词
环境学
地表水
渭河流域
硝酸盐氮
氮同位素
来源
environmentalology
surface water
Weihe River Basin
nitrate nitrogen
nitrogen isotope
source
