Identifying Salinization Using Isotopes and Ion Chemistry in Semi-Arid Region of Punjab, India

Abstract

The Semi-arid Southwest part of the Punjab has intense agricultural and industrial activity and this part is affected by groundwater salinity problems. To identify the groundwater salinity using isotopes (δ18O) and ion chemistry 22 random samples were collected from semi-arid region of South West Punjab i.e. Bhatinda district. The hydro-chemical analysis shows that the southern and western parts have high values of EC. Some areas in the district especially in north, central and small patches in south-western and eastern parts showing high values of fluoride exceeding the permissible limit of 1.5 mgL-1 for drinking water standards. The water belongs to the category of very hard water. The Na% in groundwater indicates that from 17 groundwater water sampling locations water can be used for irrigation leaving only 5 sampling locations which is found unsuitable for irrigation. The enriched δ18O values are found in the eastern and western parts of the district, while southern and northern parts are showing highly depleted values. The enriched values found between the canals Bhatinda branch and Kotla branch may be attributed to evaporation from shallow water table areas. The enriched δ18O values of groundwater are indicator of salinity. There is an increase in EC and enrichment in isotopic composition as observed in some samples due to the evaporation effect and in some samples the increase is EC is found but the isotopic composition remains constant indicating the increase in EC due to geogenic reasons. Therefore, the integrated data of ion chemistry and isotope is useful for identifying the salinity in semi-arid region.