An integrated approach for the characterization of groundwater quality using multivariate statistical techniques and spatial analysis

Ground water accessed via wells in areas of Tiruvallur district of the southern Indian state of Tamil Nadu has been a subject to increase sea-water intrusion. The present study highlights the potable water crisis in the northern district evaluated using GIS-assisted determination of water quality parameters across fifty sampling sites. The most informative parameters evaluated within this study were TDS, EC, TH, Na+, Mg2+, Ca2+, Cl- and SO42- while parameters such as pH, CO32-, etc. had limited correlated significance to water quality. The total dissolved solids (TDS) and electrical conductivity (EC) determined in the study area indicated significantly elevated levels across the sampling sites. Weighted arithmetical indexing (WAI) of the water quality parameters indicated 30 out of 50 water sources meet the tolerance limits for both drinking and irrigation. Based on BIS standards, only 13 sites met acceptable limits for safe drinking water. Principal component analysis and piper plot analysis revealed a significant involvement of Mg2+, Na+, Cl- and SO42- in the impairment of water quality, particularly in the coastal zones. Spatial hydro-chemical profiles developed in this study reveal ‘hot-spots’ of sea-water tainted water sources, and the hydro-chemical dominance of alkali earth components. Altogether, the study findings indicate a widening water crisis on top of over-exploited water resources and discuss possible factors and remedial steps in addressing the situation. KEY WORDS: Ground water, Principal component analysis, Piper Plot, Water quality index, Irrigation suitability Bull. Chem. Soc. Ethiop. 2022, 36(2), 241-260. DOI: https://dx.doi.org/10.4314/bcse.v36i2.1 &nbsp