主成分分析法在河流水质评价中的应用

摘要

The river water pollution is a serious problem,so a simple and accurate evaluation method is needed for better understanding of the pollution factors.In this paper,principal component analy-sis is used.Along a urban river,8 monitoring sites are selected,7 pollution factors including NH 3-N,NO3-N,KMnO4 ,BOD5 ,DO,TP,TN are analyzed,and two principal components are selected to reflect the overall pollution factors.As a result,an equation is established to make a comprehen-sive evaluation of the chosen principal components,the result of which is compared with the origi-nal data.The conclusion shows that PCA is a reliable method for water pollution evaluation.%河流水质的污染物种类多且具有不同程度的相关性，在不损失初始水质数据所包含信息的前提下，利用主成分方法对某河流市内河段8个断面的氨氮、溶解氧、总磷等7项水质数据进行分析，从结果中提取数量较少且不具有统计相关性的主成分变量2个，第一主成分中高锰酸钾指数、总磷、总氮有相对较高荷载，第二主成分中溶解氧、硝酸盐氮有相对较高荷载，累计方差贡献率约92％且第一主成分远大于第二主成分，进而分析该河水质的主要影响污染物类型及其所占比重，并通过主成分综合评价函数对各断面水质综合污染情况排名，结论表明主成分方法的评价结果与实际情况相符合，并达到降维、简化数据和提高分析结果可靠性等目的。