主成分分析法在城市河流水质评价中的应用

Application of Principal Component Analysis in Analyzing Water Quality of Urban Rivers

采用多元统计主成分分析方法对城市河流,即伊犁河8个监测断面的高锰酸盐指数、化学需氧量、生物需氧量、溶解氧等13个水质指标进行分析计算。结果表明:从原始数据中提取占总方差88.277%的3个因子来反映水体的污染程度,经分析识别出影响伊犁河的3个主成分因子:①以氮盐、化学需氧量、生物需氧量和溶解氧等有机污染因子控制;②悬浮物和酸碱性控制;③石油类、氨氮和生物需氧量控制。主成分分析方法能真实、准确分析出城市河流各水质指标的内在关系。

In this paper, the Principal Component Analysis is used to analyze the 13 factors （such as COD, BOD, and DO） reflecting the stream water quality at the 8 monitoring sections along the Yili River. The analyzed results reveal that stream water of the Yili River is slightly polluted at 4 sections and moderately polluted at 1 section, and the stream water quality of the Yili River is generally fine, especially in the upper and lower reaches; stream water is seriously polluted at section 5, 7 and 4 ; industrial waste and domestic sewage pollute stream water of the Yili River to some extent. The results show that the 3 principal components derived from the original data, accounting for 88. 277% of total variance, can reflect the situation of stream water pollution of the Yili River. One is the control of organic pollution factors, such as nitrogen, COD, BOD and DO; the second is the control of suspended substances, acidity and alkalinity; and the third is the control of oils. The study results also reveal that the Principal Component Analysis can be used to factually and exactly analyze the internal relations between various factors affecting the stream water quality of the Yili River.