Major ion chemistry and hydrochemical processes controlling water composition of Teesta River catchment, Sikkim Himalaya, India

The study determines the major ion chemistry of Teesta River catchment in Eastern Himalayan region and evaluates hydrochemical processes controlling water composition area. Water basin was neutral to alkaline condition. HCO3−, Ca2+, Na+, Mg2+ SO42- were identified as dominant ionic species Ca-Mg-HCO3 facies. Higher contribution (Ca2++Mg2+) HCO3− towards TZ+ TZ−, high ratios (Ca2++Mg2+)/(Na++K+), HCO3−/(Cl−+SO42-) low (Na++K+)/TZ+ ratio suggest carbonate weathering a contributor dissolved ions water. Under-saturation with respect both sulphate phase minerals suggests that can dissolve these during water-rock interaction. Concentration analysed quality parameters well below specified drinking irrigation limits.