Assessment of surface water quality parameters using multivariate analysis—A case study of Kurichi and big lakes in Coimbatore

Water quality deterioration due to industrialization and urbanization is a growing environmental concern, particularly in developing regions. This study assesses the surface water quality of Kurichi and Big Lakes in the Ukkadam area, Coimbatore, India, using multivariate statistical techniques to identify key pollution sources and evaluate contamination levels. Despite prior research on water quality in urban lakes, limited studies have systematically analyzed multiple contaminants using advanced statistical approaches. A total of 12 water samples were collected between June 2023-June 2024 and analyzed for physicochemical, microbiological, and anionic parameters. Principal Component Analysis (PCA) and Factor Analysis (FA) revealed three dominant components explaining 68.42% and 42.81% of the total variance in Kurichi and Big Lakes, respectively. The Piper plot classified water types, while Cluster Analysis (CA) grouped sampling sites based on contamination levels. The Pearson correlation matrix determined pollutant interdependencies, and the Water Quality Index (WQI) categorized pollution severity against WHO and BIS standards. The results indicate that organic matter, industrial discharge, fertilizer runoff, and untreated wastewater are the primary contributors to water pollution. High pollution levels were detected near industrial zones, with Kurichi Lake exhibiting significantly poorer water quality than Big Lake. The findings highlight the urgent need for improved wastewater management and pollution control policies to safeguard aquatic ecosystems and public health. PRACTITIONER POINTS: Multivariate Statistical Analysis: Applied PCA, FA, Piper plot, CA, and Pearson correlation matrix to assess water quality. Water Quality Index (WQI) Classification: Identified pollution sources and categorized water quality based on WHO and BIS standards. Principal Component Analysis (PCA) Findings: Three major components explained 68.42% and 42.81% of the total variation in Kurichi and Big Lakes, respectively. Major Pollution Sources: Factor analysis identified organic compounds, human activity, fertilizers, chemical waste, and wastewater discharge as primary contaminants. Industrial Area Impact: CA and WQI results highlighted high pollution sensitivity near industrial zones.