基于随机森林的秦淮河流域水体汛期污染强度影响机制  

Influencing Mechanism of Precipitation Pollution Intensity in Qinhuai River Basin Based on Random Forest

作　　者：邓雅静 李一平[1] 潘泓哲 谢鑫苗 刘军 赵明明 严春敏 郑婉婷 金巧依 DENG Ya-jing;LI Yi-ping;PAN Hong-zhe;XIE Xin-miao;LIU Jun;ZHAO Ming-ming;YAN Chun-min;ZHENG Wan-ting;JIN Qiao-yi(College of Environment,Hohai University,Nanjing 210098,China;Nanjing Environmental Monitoring Center of Jiangsu Province,Nanjing 210098,China)

机构地区：[1]河海大学环境学院,南京210098 [2]江苏省南京环境监测中心,南京210098

出　　处：《环境科学》2025年第1期193-203,共11页Environmental Science

基　　金：国家重点研发计划项目(2023YFC3208900,2023YFC3208904);南京市环保科研课题资助项目(202214);中央高校建设世界一流大学(学科)和特色发展引导专项;江苏省南京环境监测中心自主立项科研项目;环境学院研究生科研与实践创新计划项目。

摘　　要：解析流域汛期污染强度分布特征,识别影响汛期污染强度的主要因素是实现面源污染精准治理的重要基础.基于收集的2021~2022年秦淮河流域干流河道4个典型断面地表水水质数据和降雨数据,计算流域汛期污染强度并解析其分布特征,选取具有代表性的自然和社会因素,构建基于随机森林算法的氨氮(NH_(4)^(+)-N)、高锰酸盐指数和总磷(TP)汛期污染强度模型,识别各指标汛期污染强度的主要驱动因素并分析其影响机制.结果表明,降雨是导致秦淮河流域断面水质超标的主要驱动因素,研究区域断面水质超标3 d内有降雨事件的占比在61.4%~97.4%之间.NH_(4)^(+)-N和TP汛期污染强度呈现由上游至下游逐渐增加的趋势,NH_(4)^(+)-N是中游七桥瓮断面和下游三汊河口断面的首要污染物,汛期污染强度分别为0.12~2.98和0.31~3.84,上游洋桥断面高锰酸盐指数汛期污染强度最大,为0.41~1.35,位于引江清水通道上的将军大道断面各指标汛期污染强度相较于其余3个断面均处于较低水平.引水量是NH_(4)^(+)-N和高锰酸盐指数汛期污染强度降低的重要影响因素(P<0.01),建成区面积占比与NH_(4)^(+)-N和TP汛期污染强度呈显著正相关,耕地面积占比与高锰酸盐指数汛期污染强度呈显著正相关,林地面积占比与这3个指标汛期污染强度呈显著负相关.在小雨、中雨和大雨情况下,场次降雨量与各指标汛期污染强度均呈显著正相关,暴雨情况下汛期污染强度维持在较高值.NH_(4)^(+)-N和TP雨后污染主要来源于研究区域中下游,受建成区面积占比和引水量等区域特征影响显著(P<0.01),高锰酸盐指数雨后污染主要来源于耕地面积分布较广的上游地区,受流量影响显著(P<0.01).Analyzing the distribution characteristics of precipitation pollution intensity in the basin and identifying the main factors affecting the precipitation pollution intensity are the important basis for realizing the accurate management of diffused pollution.Based on the surface water quality data from four typical sections of the main stream of Qinhuai River Basin and rainfall data collected from 2021 to 2022,the distribution characteristics of precipitation pollution intensity in the basin were analyzed,and representative natural and social factors were selected to construct models of the precipitation pollution intensity of ammonia nitrogen(NH_(4)^(+)-N),permanganate index,and total phosphorus(TP)based on random forest algorithm.Additionally,the main driving factors of precipitation pollution intensity were identified,and the influencing mechanism was analyzed.The results showed that rainfall was the main driving factor for the water quality exceeding the standard in the Qinhuai River Basin,and the proportion of rainfall events within 3 days of when the water quality of the sections in the study area exceeded the standard was between 61.4%and 97.4%.The precipitation pollution intensity of NH_(4)^(+)-N and TP showed a gradual increase from upstream to downstream.NH_(4)^(+)-N was the primary pollutant in the midstream Qiqiaoweng section and the downstream Sanchahekou section,with the precipitation pollution intensity ranging from 0.12 to 2.98 and from 0.31 to 3.84,respectively.The precipitation pollution intensity of permanganate index in the upstream Yangqiao section was the largest,ranging from 0.41 to 1.35,and the precipitation pollution intensity of the Jiangjundadao section,which is located on the channel of diverted water,was at a lower level compared with that of the other three sections.Water diversion was an important influencing factor for the reduction of precipitation pollution intensity of NH_(4)^(+)-N and permanganate index(P<0.01);the proportion of builtup area was significantly positively correlat

关 键 词：汛期污染强度 分布特征 影响因素 随机森林 秦淮河流域 

分 类 号：X522[环境科学与工程—环境工程]