基于多元统计的沱江支流釜溪城镇河流污染特征解析

Analysis of urban river pollution characteristics of Fuxi River,a tributary of Tuojiang River by multivari⁃ate statistical model

小城镇河流具有污染来源复杂、水质污染程度较高和水文监测资料缺乏等问题,精准解析污染源对流域水污染治理具有重要意义。本研究以沱江一级支流釜溪河为研究区域,基于2018—2020年各监测断面的水质监测数据,分别采用内梅罗污染指数法和多元统计模型对该河流进行水质污染综合评价和污染源解析。结果表明,2018年釜溪河流域以中度污染为主,2019年和2020年流域以轻⁃中度污染为主;流域在丰水期和平水期以轻⁃中度污染为主,枯水期流域属于中度污染,流域干流水质优于支流。流域主要污染源为农业⁃畜禽养殖混合源、生活⁃畜禽养殖混合源、自然源和有机污染源,其中对化学需氧量(CODMn)和总磷贡献较大的污染源为农业⁃畜禽养殖混合源,分别为7.8%和11.8%,对氨氮和总氮贡献较大的污染源为生活⁃畜禽养殖混合源,分别为59.4%和23.8%,对五日生化需氧量贡献较大的污染源为有机污染源,达到12.1%。本研究提出的基于多元统计技术的流域污染特征解析框架能够快速准确地解析水文数据缺乏和污染来源复杂的河流流域污染源及其贡献率,可为沱江流域支流水环境管理提供科学依据,也为类似沱江流域支流的小城镇河流水质污染特征和污染来源解析提供方法借鉴。

Small sized rivers in towns are facing the problems such as complex pollution sources,serious water pol⁃lution,and lack of hydrological monitoring data.It is thus of great significance to accurately analyze pollution source for watershed water pollution control.Based on water quality monitoring data of each monitoring section of the Fuxi River,a primary tributary of Tuojiang River from 2018 to 2020,we comprehensively evaluated water pollution using the Nemerow pollution index and analyzed pollution sources using the absolute principal component score⁃multiple linear regression model.Results showed that water quality of Fuxi River basin was mainly in moderate pollution level in 2018,while in mild⁃moderate pollution level in 2019 and 2020.Water quality of the basin was mainly in light to moderate pollution level in wet season and normal season,while in moderate pollution level in dry season.Water quality of the main stream was better than that of the tributaries.Agricultural⁃livestock and poultry breeding mixed sources,domestic⁃livestock and poultry breeding mixed sources,natural sources,and organic pollutant sources were main pollution sources in the basin.The agricultural⁃livestock and poultry breeding mixed sources contributed greatly to chemical oxygen demand(CODMn)and total phosphorus concentrations,with a contribution rate of 7.8%and 11.8%,respectively.As for ammonia and total nitrogen,the main pollution sources were domestic⁃livestock and poultry breeding mixed sources,with a contribution rate of 59.4%and 23.8%,respectively.For five⁃day bio⁃chemical oxygen demand,the main contributor was organic pollutants,with a contribution rate of 12.1%.The framework of watershed pollution analysis based on multivariate statistical technology proposed in this study can be used to quickly and accurately analyze the pollution sources and their contribution rates in river basins with hydro⁃logical data lacking and complex pollution sources,which provides a scientific basis for water environmental man⁃agement in tributaries of Tuojiang River basin and a reference for the analysis of water pollution characteristics and pollution sources in other rivers with small towns similar to the tributaries of Tuojiang River basin.