基于多种方法的长江上游小流域水质综合评价

Comprehensive Evaluation of Water Quality in Small Watershed of Upper Yangtze River Based on Multiple Methods

选取大河和巴关河流域2018—2022年水质监测数据,运用单因子评价法、Spearman秩相关系数法、综合污染指数法和主成分分析法,对流域水质状况、变化趋势及主要污染物特征进行综合评价分析。结果表明:2018—2022年,大河流域水质未达到地表水Ⅲ类标准;流域整体综合污染指数超过了1,为重污染,下游污染程度较重;营养指标和有机污染物指标存在显著正相关。巴关河流域水质达到了地表水Ⅲ类标准;流域整体综合污染指数未超过1,为中污染,上游污染程度较重;营养指标、有机污染物指标和重金属指标等均呈现出不同程度的相关性。巴关河流域水质总体优于大河流域。TP、NH_(3)-N、COD_(Mn)、COD_(Cr)和BOD_(5)是影响大河流域和巴关河流域水质的主要因子,均属于有机型及富营养化污染指标,主要来自生活源和农业源。建议选择适宜的评价方法开展系统性小流域污染溯源,分河段有针对性地开展小流域水环境治理。

The water quality monitoring data of the Dahe River Basin and the Baguan River Basin from 2018 to 2022 were selected,and the single factor evaluation method,Spearman rank correlation coefficient method,comprehensive pollution index method and principal component analysis method were used to comprehensively evaluate and analyze its water quality status,change trend and main pollutant characteristics.The results showed that from 2018 to 2022 the water quality of the Dahe River Basin did not meet the ClassⅢstandard of surface water.The comprehensive pollution index exceeded 1,which was heavy pollution.The downstream pollution was serious.There was a significant positive correlation between nutrition index and organic pollutant index.The water quality of the Baguan River Basin reached the surface water classⅢstandard.The comprehensive pollution index did not exceed 1,which was medium pollution.The pollution degree in the upper reaches was heavy.The nutrition index,organic pollutant index and heavy metal related index all showed different degrees of correlation.The water quality of the Baguan River Basin was generally better than that of the Dahe River Basin.The main factors affecting the water quality of the Dahe River Basin and the Baguan River Basin were TP,NH_(3)-N、COD_(Mn)、COD_(Cr),BOD_(5),which belong to organic and eutrophic pollution index,mainly from domestic sources and agricultural sources.It was recommended to select appropriate evaluation methods,carry out systematic pollution traceability of small watersheds,and carry out targeted water environment management of small watersheds by river reaches.