渭河西咸段水质时空变异特征分析

为查明西咸新区地表水环境质量状况,对其范围内的三条河流进行了连续两年的水质监测,并运用层次聚类、判别分析、主成分分析等多元统计方法对污染物的时空分布差异进行了分析。结果表明:研究河段整体氮磷污染严重,总氮(TN)超过地表水Ⅳ类水质标准7.62倍,总磷(TP)超标3.60倍,氨氮(NH3-N)超标1.89倍。聚类分析结果表明,水质在时间尺度上按水质优劣可分为丰水期、平水期、枯水期三类;在空间尺度上,渭河、沣河水质分为一类,新河为一类。研究区水质污染受上游来水水质的影响较大,上游的生活污水、工业废水排放以及农业面源污染是渭河干流的主要污染源,沣河主要为农业面源污染,而新河是以人为污染为主。

Spatiotemporal characteristics analysis of water pollutants in Xixian New Area in Weihe River basin

To find out the surface water quality in Xi-xian New Area, we monitored the water quality in three rivers in this area for two years. And we used cluster analysis, discriminant analysis, and factor analysis to examine the spatial and temporal distributions of pollutants and their variations in the study area, along with an analysis of the pollution sources. The results show that the nitrogen and phosphorus pollution is severe in the monitored river sections, with the total nitrogen (TN) exceeding the Class IV surface water quality standard level by 7.62 times, total phosphorus (TP) by 3.60 times, and ammoniacal nitrogen (NH3-N) by 1.89 times. Cluster analysis shows the water quality falls into three categories in different seasons: wet season of June through October, normal season of March through May, and dry season of November through February. Spatially, it falls into two categories, one cluster for the water quality in the Weihe River and the Fenghe River, and the other for the Xinhe River. Water pollution in the monitored river sections is greatly influenced by the quality of their upstream inflow. In the mainstream Weihe, the major pollution sources are the domestic sewage, industrial wastewater, and agricultural non-point pollutants discharged in its upstream regions; Fenghe’s major pollution source is agricultural pollutants; Xinhe’s pollutants largely come from anthropogenic pollution.