Chemometrics in assessment of seasonal variation of water quality in fresh water systems.

The chemometric techniques were applied for evaluation of the seasonal variation of water qualities at 17 stations along a stretch of the Bagmati river of Nepal for 23 water quality parameters measured during 1999-2003. The application of discriminant analysis confirmed the classification of the water quality measurements into three seasons: pre-monsoon, monsoon, and post-monsoon affording 93.8% correct classification. Factor analysis and box-whisker plots facilitated to investigate the seasonal variation of water quality and the pattern of pollution sources. Application of FA revealed that the influence of water quality parameters changes from season to season. A parameter that is most important in contributing to water quality variation for one season may not be important for another season. Comparison of the discriminant analysis and factor analysis helped to identify the most important water quality parameters, as water temperature, DO, EC, COD, CL, Ca, alkalinity, PO(4)P, and TP, that are most important for seasonal variation and play a significant role in establishment of water quality control strategy.