Comparative Study of Groundwater Quality for Drinking and Irrigation Purposes in Selected Villages of Manipur, India

Abstract

A comparative study was done to monitor the groundwater qualities, both for drinking as well as irrigation purposes in some villages of Imphal East district, Manipur, in the period of pre-monsoon and monsoon of 2021. Totally, fifteen (15) groundwater samples were collected and examined for some important parameters like temperature, pH, TDS, TH, TA, Mg2+, K+, HCO3-, Ca2+, CO32-, Na+, Cl-, NO3- and SO42-. The results revealed that all the groundwaters were slightly alkaline in nature and fall under freshwater category. In both the seasons, majority of the parameters for various groundwaters have found their values/ concentrations below its acceptable limits, as given by BIS and WHO. In pre-monsoon, 73.33% of groundwaters were found as ‘moderately hard water’ and 26.67% (hard water) whereas in monsoon, 60% (moderately hard water) and 40% (hard water). Dominant ions in both seasons were Na+ (sodium) and HCO3- (bicarbonate) for cations and anions respectively. In most of the samples of monsoon, values and concentrations of the studied parameters were observed to be greater/higher as compared to that of pre-monsoon. It was mainly due to the leaching out of the soluble salts in the earth’s crust by rainwaters and finally mingled with the groundwater bodies in the aquifers in monsoon season. WQI values showed that in pre-monsoon, 26.67% of groundwaters were found as excellent water, 66.67% (good) and 6.66% (poor) while in monsoon, 60% (good) and 40% (poor). For irrigation water qualities, the indices (RSC, SAR, %Na, PI and KR) were examined. In the overall, all the samples can be utilized for irrigation (agriculture) purposes in both seasons. Correlation co-efficient (r) values showed that in both the seasons, the TH of various groundwaters was mainly because of dissolved sulphates of Ca2+ along with Mg2+.