Hydrogeochemical characteristics and groundwater contamination in the rapid urban development areas of Coimbatore, India

The Singanallur Sub-basin is one of the major waterways and it supplies water to the Coimbatore city. Currently, it is vulnerable to pollution due to an increase of unplanned urban developments, industrial, and agricultural activities that compromise both the quality and quantity. In the present study three major hydrochemical facies were identified (mixed Ca-Mg-Cl, Ca-Cl, and Ca-HCO3). Irrigation suitability indexes are specifies that the groundwater in the areas has very high salinity hazard and low to medium alkali hazard. The mechanism controlling groundwater chemistry originally regulated by the evaporation process is dominated by reason of arid condition and anthropogenic activities existing throughout the region. The multivariate statistical analysis (Correlation analysis (CA), principal component analysis (PCA) and Hierarchical cluster analysis (HCA)) indicates, most of the variations are elucidated by the anthropogenic pollutant predominantly due to population growth, industrial effluents, and irrigation water return flow. This study demonstrates enhanced information of evolution of groundwater quality by integrating hydrochemical data and multivariate statistical methods are used to understand the factors influencing contamination due to natural and anthropogenic impacts.