Assessment of water quality and identification of pollution sources of plateau lakes

The plateau lakes of Vunnan are important both ecologically and economically in China. Nevertheless, the human impact on water qual-ity in these lakes has become increasingly highlighted. The water quality of 10 plateau lakes was monitored regularly over the period of 200(0 through 2004 for 24 parameters. Multivariate statistical tech-niques, including cluster analysis (CA), factor analysis (FA), and prin-cipal component analysis (PCA), were employed to better interpret information about the water quality and its pollution sources. No obvious data reduction from CA/FA was found because three principal conp)onents (PCs) needed 14 variables to explain 85.01 % of the total variance. However, three latent factors accounted for pollution mainly from the following sources: agricultural activities, residential activities and anthropogenic-toxic pollution from industrial effluents, or other special activities. Box-whiskers plots were employed to visually in