基于主成分分析及水质标识指数法的南通海门区浅层地下水水质评价

Water quality evaluation of Gaoyou Lake based on principal component analysis and water quality identification index method

为了充分掌握南通海门区浅层地下水水质分布特征,根据2020年12月份-2021年3月份采集的水质检测数据,运用SPSS软件进行主成分分析,并采用水质标识指数法进行定性和定量评价。主成分分析将11个水质指标综合为3个主成分进行解释,解释率为77.062%。水质标识指数法中单因子指数将水质划分为Ⅲ、Ⅳ及Ⅴ类,综合指数评价水质Ⅲ类标准达标率为48%,指数大小排序基本一致。分析结果表明:超标严重的指标(NO_(3)^(-)、Fe)易掩盖其他水质指标信息,对水质类别判定影响较大;主成分分析法和水质标识指数法对于主要污染指标的评价结论基本吻合,点位污染指数次序一致性较好;水质污染程度整体表现为:城镇工业区>农业种植、养殖区>其他地区,说明城镇化进程及工业生产以及农业种植、畜禽养殖是海门区浅层地下水水质污染的重要因素。采用两种评价方法相结合,既能筛选出水质污染指标,又能在水质优劣排序基础上填补水质类别信息,使评价结果更加详实、可信。

In order to fully grasp the distribution characteristics of shallow groundwater quality in Haimen District,Nantong,based on the water quality testing data collected from December 2020 to March 2021,SPSS software was used for principal component analysis,and the water quality identification index method was used for qualitative and quantitative evaluation.Principal component analysis combined 11 water quality indicators into 3 principal components for interpretation,with an explanatory rate of 77.062%.In the water quality identification index method,the single factor index divides water quality into Class III,IV,and V.The comprehensive index evaluates the compliance rate of Class III water quality standards at 48%,and the ranking of index sizes is basically consistent.The analysis results indicate that indicators with severe exceeding standards(NO_(3)^(-),Fe)are prone to masking information from other water quality indicators and have a significant impact on the determination of water quality categories;The evaluation conclusions of the principal component analysis method and the water quality identification index method for the main pollution indicators are basically consistent,and the consistency of the order of point pollution indices is good;The overall degree of water pollution is as follows:urban industrial zone>agricultural planting and breeding zone>other areas,indicating that the urbanization process,industrial production,agricultural planting and animal husbandry are important factors for shallow groundwater water pollution in Haimen District.The combination of two evaluation methods can not only screen out water pollution indicators,but also fill in water quality category information based on water quality ranking,making the evaluation results more detailed and reliable.