APCS-MLR结合PMF模型的塔里木河上游沉积物重金属源解析与风险评估

APCS-MLR combined with PMF model for sediment heavy metal source analysis and risk assessment in the upper Tarim River Basin

为探究塔里木河上游沉积物中重金属的污染来源及潜在生态风险,选取上游阿拉尔—沙雅段表层沉积物为研究对象,测定Cu、Fe、Zn、Pb、As、Cr、Cd、Mn和Ni等9种重金属的含量,分析其污染及空间分布特征.结合相关性分析、聚类分析、绝对主成分-多元线性回归(APCS-MLR)和正定矩阵因子分析(PMF)等解析污染来源及其贡献,运用富集系数法、地质累积指数法、沉积物污染指数法和沉积物质量基准法(SQG)对重金属进行了风险评估.结果表明,除As外,Cu、Fe、Zn、Pb、Cr、Cd、Mn和Ni的平均含量均超过背景值;空间上重金属含量较高的采样点基本都出现在河流汇合处及人类活动的密集区.相关性分析、聚类分析和PCA/APCS分析表明,塔里木河上游沉积物的重金属来源主要有3类,第Ⅰ类中Cu、Fe、Zn、Pb、Mn和Ni可能代表禽类粪便和自然来源;第Ⅱ类中As、Cd和Ni可能代表农业活动源;第Ⅲ类中Pb和Cr可能代表交通活动源.APCS-MLR和PMF模型表明,源贡献率最高的是农业活动源,贡献率分别为63.20%和52.36%;养殖和自然来源、交通活动源是解析出的其他2个源,APCS-MLR和PMF解析得到的贡献率分别为10.80%、26.00%和36.09%、11.55%.风险评估方法均表明Cd和Ni处于轻度污染,偶尔会产生生物毒性效应;Zn无污染,生物毒性效应很少发生;塔里木河上游沉积物整体为自然-低风险水平,但样点TH1、TH4和TH7可能存在潜在生态风险.

In order to explore the pollution sources and potential ecological risks of heavy metals in sediments in the upper Tarim River Basin,the surface sediments of the Aral-Shaya section of the upper reaches were selected as the research objects,and the contents of nine heavy metals elements,including Cu,Fe,Zn,Pb,As,Cr,Cd,Mn,and Ni,were determined,and their pollution and spatial distribution characteristics were analyzed.Combined with correlation analysis,cluster analysis,Absolute Principal Component Score-Multiple Linear Regression(APCS-MLR)and Positive Matrix Factorization(PMF)to analyze pollution sources and their contributions,the risk assessment of heavy metals was carried out by cluster analysis,geological cumulative index,sediment pollution index method and environmental quality standard for sediments(SQG).The results showed that except As,the average contents of Cu,Fe,Zn,Pb,Cr,Cd,Mn and Ni exceeded the background value;The sampling points with high spatial heavy metal content are basically found at river confluences and areas with dense human activities.Correlation analysis,cluster analysis and PCA/APCS analysis showed that the sources of heavy metals in sediments in the upper Tarim River Basin were divided into three categories,and the first category was Cu,Fe,Zn,Pb,Mn and Ni,which may represent poultry manure and natural sources.Category 2 are As,Cd and Ni,which may represent sources of agricultural activity;Class 3 are Pb and Cr,which may represent sources of traffic activity.The APCS-MLR and PMF models showed that the highest contribution rate of the source was from agricultural activities,with the contribution rate of 63.2%and 52.36%,respectively.The contribution rates of APCS-MLR and PMF analysis of aquaculture sources,natural sources and transportation activity sources were 10.8%,26.0%,36.09%and 11.55%,respectively.Risk assessment methods all showed that Cd and Ni were mildly contaminated and occasionally had biotoxic effects;Zn is pollution-free,and biological toxicity effects rarely occur;The sediments in the upper Tarim River are naturally natural-low risk levels overall,but there may be potential ecological risks at the sites TH1,TH4 and TH7.