Nipra Sharma¹, Priyanka Kumari², Amarjeet Kaur^2,

Groundwater (GW) is a major source of drinking water in many parts of the National Capital Region (NCT) Delhi including the southwest part of the city. To assess the GW quality in the study area total 52 GW samples were collected for both pre and post monsoon season for two consecutive years (2019-20) from 13 sampling locations. These samples were then analyzed for 16 physical and chemical water quality parameters including pH, Temperature, EC, Salinity, TDS, alkalinity, TH, NO₃^-, PO₄^2-, SO₄^2-, F^-, Cl^-, Ca²⁺, Mg²⁺, Na⁺ and K⁺. Descriptive analysis and normality check was executed before subjected to multivariate analysis. Pearson correlation explained, positively high correlation coefficient(r) for both pre and post monsoon seasons between TDS and Cl^- (r=0.97(pre) and 0.93(post)); salinity and EC(r=0.82(pre) and 0.82(post)); TDS and TH(r=0.86(pre)and 0.83(post)); Na⁺ and Mg²⁺ (r=0.80(pre) and 0.81(post)). Factor Analysis depicted TDS, alkalinity, TH, SO₄^2-, F^-, Cl^-, Ca²⁺ were significantly loaded components for both the seasons, contributing for 77.84% (pre monsoon) and 82.31% (post monsoon) of component loading respectively. Degradation of water quality is majorly due to growing population and human interventions adding to the diversity of topography and the geology. The interpolation maps generated depict high concentration of alkalinity, salinity, total dissolved solids (TDS), and electrical conductivity (EC) across the study area’.

groundwater quality, Delhi, principal component analysis, Pearson correlation, seasonal variation