Application of chemometric analysis for identifying pollution sources: a case study on the River Adyar, India

The various factors responsible for the chemical budget and pollution of river water have been evaluated and characterised using various statistical tools. The potential sources of pollution that alter the chemical composition of River Adyar water have been identified and quantified. Thirty-three samples were collected from the River Adyar and basic chemical parameters and heavy metals were interpreted by the systematic application of statistical techniques. The relationships among the various ions were examined and the sources of origin were evaluated using correlation studies. An R-mode factor analysis revealed that the chemistry of the river water largely depends on anthropogenic activities, rock–water interaction and saline water intrusion. A cluster analysis was applied and the major and minor clusters for pre-monsoon and post-monsoon seasons were classified. This classification was found to be in line with the results of the R-mode factor analysis. Seasonal variation in the chemistry and pollution level of the river water was clearly indicated by both cluster and factor analyses. Factor scores, which give vital information on the variation of the factors by station, were successfully applied. The contributing factors and any seasonal effect on the stations were evaluated and interpreted.