Multivariate analysis and geochemical signatures of groundwater in the agricultural dominated taluks of Jalandhar district, Punjab, India

The present study is focused on the agriculturally dominated taluks of Nakodar, Shahkot and Phillaur in Jalandhar district, Punjab. Integrated multivariate technique along with geochemical signatures and vertical depth profiles of major ions were studied to assess the hydrogeochemical characteristics, processes influencing the aquifer chemistry and suitability appraisal for different uses. The analytical results revealed that the groundwater is hard to very hard in nature and their relative abundance of major ions are Na+ > Mg2+ > Ca2+ > K+ and HCO3– > SO42− > CO32– > Cl− > NO3− > F− > PO42− respectively. Elevated levels of NO3− (2 samples) in Phillaur taluk and F− (1 sample in every three taluks) were observed in shallow aquifer of the study area. The overall results of the water quality index show that a major part of the study area possesses good water quality. The taluk wise WQI results depict that certain pockets fall in poor (3 samples in Phillaur, 1 in Shahkot) to very poor (1 sample of Nakodar) water classes. The chemical compositions of the study area were predominantly Ca2+–Mg2+–HCO3– followed by Ca2+–Mg2+–Cl−–SO42−facies. Both Nakodar and Shahkot taluk shows Na+-Mg2+–HCO3– water type, while Phillaur taluk shows Mg2+–HCO3– water type. The water type of the shallow aquifer is complex in nature showing Na+-Mg2+–HCO3– type, further it changed to Na+–HCO3– in the intermediate zone. Interpretation of the geochemical signatures of the groundwater suggested that natural weathering and dissolution of silicate and carbonate minerals and ion exchange process are largely controlling the aquifer chemistry. Principal component analysis (PCA) extracts five principal components (PC's), where PC1, PC2 and PC4 are influenced by mixed factors i.e., lithogenic and anthropogenic inputs. PC3 is exclusively affected by anthropogenic factors like domestic sewage, fertilizer and irrigation return flow respectively and PC5 is mainly controlled by natural factors.