Assessment of Ground Water Qualities of Some Areas of Imphal West District of Manipur during Pre-Monsoon – 4th Phase

Fifteen ground water samples (S-1 to S-15) were collected from 12 hand pumps and 3 dug wells of Imphal West district of Manipur during pre-monsoon period(May) of 2015. They were analyzed for physicochemical parameters such as temperature, p_H, TDS (total dissolved solids), electrical conductivity (EC), total alkalinity (TA) (and hence CO^2-₃ and HCO^-₃), total hardness (TH), Ca²⁺, Mg²⁺, Na⁺, K⁺ and Cl^-. Ground waters represented by S-1,S-2,S-10,S-11 and S-13 to S-15 are found to be fit for drinking purpose from physicochemical analysis point of view. But TDS values for S-3 and S-4, total alkalinity values for S-3 to S-9 andS-12, total harness value for S-8, concentration of Mg²⁺ for S-8, and concentrations of Na⁺ for S-3 and S-4 are above their corresponding acceptable limits but below the permissible limits of BIS standard for drinking water and threshold limit of WHO (in case of Na⁺). So, some suitable treatments are necessary so as to keep the values/concentrations of the above mentioned parameters below their corresponding acceptable limits/threshold limit of BIS standard for drinking water and that of WHO. However, ground waters represented by S-3 to S-9 and S-12 are fit for drinking in absence of alternate sources. All the ground waters (S-1 to S-15) are fit for other domestic and irrigation purposes.

Further correlation coefficient data reveals that TA shows strong positive correlations with HCO₃^-, Na⁺ and Mg²⁺ (r= 1, 0.892 and 0.649 respectively) but moderately strong positive correlation with Ca²⁺ (r=0.541) showing that the total alkalinity of such ground waters is due to the presence of NaHCO₃, CaHCO₃ and MgHCO₃. Strong positive correlations of TH (total hardness) with Ca²⁺, Mg²⁺ and HCO₃^- (r = 0.944, 0.970 and 0.629 respectively) show that total hardness for these different ground waters, is due to the presence of CaHCO₃ and MgHCO₃.