Pathways of major ion chemistry and evaluation of contaminants in the River Ajay, India

ABSTRACT Hydro-geochemical studies of water quality and identification of polluting agents present in the river system are important for the sustainable utilization of water resources. This study focuses on the evaluation and interpretation of major ion chemistry, hydro-geochemical processes, and the suitability of water quality in domestic and agricultural usage areas. The water quality parameters, total dissolved solids (TDS), electrical conductivity (EC) and NO3− have wide variations along the sampling sites. The river has Ca2+, Mg2+ and NO3− dominant ions. The chemistry of water is largely determined by rock weathering and ion exchange processes with low contribution from anthropogenic sources. The water of the Ajay River is not suitable for drinking and irrigation purposes due to high levels of TDS, EC, NO3−, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total coliform (TC) and fecal coliform (FC). Principal component analysis (PCA) suggests that rock weathering, atmospheric deposition and anthropogenic activities together influence the water quality/chemistry. The Water Quality Index (WQI) indicated that 78% of water falls under medium, 15.7% under bad and only 5.2% of water falls under good category. Thus, this study illustrates the identification of pollution sources and interpretation of the complex data of the Ajay River that will be helpful for river water quality management for this river in particular and other river systems of the globe in general.