主成分分析法在北方某市饮用水水质综合评价中的应用

Application of principal component analysis on the comprehensive evaluation of drinking water quality in a city of northern China

目的评价出厂水水质卫生状况,掌握影响水质的主要指标,探索主成分分析方法在水质综合评价中的应用,为更好地进行水质监测提供理论依据。方法采用主成分分析方法对北方某市2013-2014年集中式供水出厂水的水质进行综合评价。结果相关系数矩阵显示,溶解性总固体与氯化物和钠高度相关;总硬度与硝酸盐和耗氧量存在较高的相关性;氟化物与钠和pH存在较高的相关性;微生物指标之间高度相关。提取的6个主成分累积方差贡献率为86.159%,影响本市水质的主要指标分别为第一主成分中的硝酸盐、总硬度和耗氧量,第二主成分的菌落总数、总大肠菌群、耐热大肠菌群和大肠埃希菌,第三主成分的氟化物、pH和钼,第四主成分的氯化物和硼,第五主成分的氨氮,第六主成分的色度。主成分综合得分显示水厂41的出厂水水质最好,水厂33的出厂水水质相对较差。结论主成分分析方法是一种较好的水质综合评价的多元统计方法,相关部门应针对影响水质的主要指标和水质相对较差的水厂,采取有效措施,加强监测,加强监督管理,确保居民饮水卫生安全。

Objective To explore the application of principal component analysis （PCA） on the comprehensive evaluation of drinking water quality, and to provide theoretical basis for the monitoring of drinking water. Methods PCA was performed to evaluate the quality of drinking water in a city of northern China from 2013 to 2014. Results Correlation coefficient matrix showed that total soluble solid was highly relevant with chlo- ride and sodium; total hardness was highly relevant with nitrate and oxygen consumption; fluoride was highly relevant with sodium and pH, and high relevance existed among microbial indicators. The cumulative variance contribution rate of the extracted 6 principal factors was 86. 159 %. The major influencing indexes for drinking water quality were nitrate, total hardness and oxygen consumption in the first principal component, aerobic bacteria count, total coliform group, heat resisting coliform group and escherichia coli in the secondary princi- pal component, fluoride, pH and molybdenum in the third principal component, chloride and boron in the fourth principal component, ammonia nitrogen in the fifth principal component and chroma in the sixth princi- pal component, respectively. The comprehensive scores showed that the water quality was the highest in water plant 41 and the lowest in water plant 33. Conclusions PCA is considered to be a better multivariate statistical method for drinking water quality evaluation. In order to ensure the high quality of drinking water for local residents, effective measures should be taken to enhance the monitoring, supervision and management of drinking water.