Environmental Tracers in the Identification of the Groundwater Salinity—Case Studies from Northwest India

Abstract

In the face of the burgeoning climate crisis and ever-increasing human consumption demands, the disparate distribution of the water cycle is greatly amplified, resulting in frequent extreme events like drought and flooding. Groundwater is the essential component of this water cycle which interacts with all other parameters. Several large aquifers worldwide face huge water scarcity due to excessive groundwater pumping for agricultural and industrial demand, reduced infiltration capacity due to land-use changes, and human-induced climate crises. The sub-surface component and the stream discharge of major rivers, supporting massive civilizations, are on the verge of drying up due to decreased base flow. Groundwater has been largely used as a major source of irrigation water. Its excessive use and a change in cropping pattern have led to its declination in quantity and deterioration in quality (MacDonald et al. 2016; Siebert et al. 2010; Wada et al. 2014). In addition to the anthropogenic contaminants in groundwater such as nitrates, pesticides, feeds (Burow et al. 2008; Harter et al. 2012), and geogenic pollutants such as arsenic, uranium, fluoride (Jurgens et al. 2010; Ravenscroft et al. 2013; Smith et al. 2018) groundwater is also contaminated by total dissolved solids (TDS) occurring naturally or anthropogenically cause groundwater salinity (Triki et al. 2014). One significant impact of low water quantity is on surface–subsurface water quality. In conditions of low aquifer recharge, the incomplete dilution of dissolved solids in groundwater leads to a spike in TDS levels inside the aquifer.