暴雨前后河南北部河流水质分异特征及其污染源解析

Differential Characteristics and Source Identification of Water Quality of the Rivers in Northern Henan Before and After Rainstorm

为了探究暴雨前后河南北部河流水质分异特征并对其污染源进行识别,选取了暴雨前后6个监测断面和8个水质指标的监测数据,利用箱线图、相关性分析和绝对主成分-多元线性回归模型等方法分析了暴雨前后河南北部河流水质指标的差异性及其变化过程,并计算了污染源的绝对贡献率.结果表明,pH、DO、EC和TN的值暴雨后比暴雨前有所降低,而浊度、高锰酸盐指数、NH_(4)^(+)-N和TP的值暴雨后比暴雨前有所增加,其中TP的变化率最大为177.17%;DO、高锰酸盐指数、NH_(4)^(+)-N和TP暴雨后处于Ⅳ类及以上水质标准占比明显增加,增加幅度分别为65.12%、34.26%、15.29%和37.46%;各监测断面水质指标在暴雨前后均有不同程度的差异性,其中pH值的差异性最小,而浊度、NH_(4)^(+)-N和TP的差异性较大;暴雨后pH和DO与其他水质指标的相关性有所增加,而浊度、高锰酸盐指数、NH_(4)^(+)-N、TP和TN相互间的相关性在暴雨后有所减小;暴雨前河流水质指标受到气象因子和河流水体内源的影响较大,暴雨后城市污染源对TN的绝对贡献率最大为60.53%,气象因子对DO、NH_(4)^(+)-N和TP的绝对贡献率分别为43.03%、46.11%和42.22%,农业面源对高锰酸盐指数的绝对贡献率较大为65.60%,未识别污染源对pH的绝对贡献率最大为60.04%.

To explore the water quality differential characteristics and identify pollution sources of rivers in Northern Henan before and after rainstorms,the monitoring data of eight water quality indexes in six monitoring sections before and after a rainstorm were selected.The change characteristics,differences,and change process of river water quality indexes in Northern Henan before and after the rainstorm were analyzed by using a box diagram,correlation analysis,and an absolute principal components-multiple linear regression model(APCS-MLR),and the absolute contribution rates of pollution sources were calculated.The results showed that the values of pH,DO,EC,and TN after the rainstorm were lower than those before the rainstorm,whereas the values of turbidity,permanganate index,NH_(4)^(+)-N,and TP increased after the rainstorm,and the maximum change rate of TP was 177.17%.The proportions of DO,permanganate index,NH_(4)^(+)-N,and TP in class IV and above water quality standards increased significantly after the rainstorm,with increase rates of 65.12%,34.26%,15.29%,and 37.46%,respectively.The water quality indexes of each monitoring section were different before and after the rainstorm,and the difference in pH value was the smallest,whereas the differences in turbidity,NH_(4)^(+)-N,and TP were relatively larger.The correlations between pH and DO and other water quality indexes increased after the rainstorm,whereas the correlations between turbidity,permanganate index,NH_(4)^(+)-N,TP,and TN decreased significantly after the rainstorm.Before the rainstorm,the water quality indexes of the rivers were greatly affected by meteorological factors and those endogenous to the water body.After the rainstorm,the absolute contribution rate of urban pollution sources to TN was 60.53%;the absolute contribution rates of meteorological factors to DO,NH_(4)^(+)-N,and TP were 43.03%,46.11%,and 42.22%,respectively;the absolute contribution rate of agricultural non-point sources to the permanganate index was 65.60%;and the absolute contribution rate of unidentified pollution sources to pH was 60.04%.