Evaluation of Groundwater Quality by Water Quality Index During Successive Periodic Intervals in the Selected Villages of Gara Mandal of Srikakulam District in Andhra Pradesh

The quality of groundwater is assessed using the Water Quality Index method and it is pertinently helpful to transfer the complex data into usable data. In this research study the WQI values have been estimated for each water sample (in total, 66 samples have been collected) based on 9 water quality parameters at periodic intervals in May 2015, 2016 and 2017 in the villages of Gara Mandal of Srikakulam District in Andhra Pradesh. The overall results disclosed that 50-54% of the groundwater samples (WQI lies between 100-200) showed poor quality and 10-13% of water samples (WQI lies between 200-300) showed very poor quality in successive periodic intervals. An assessment of measured physicochemical parameters of 66 sample sites has shown that the majority of the groundwater samples have a high concentration of calcium, magnesium, sodium, chloride and sulfate ions beyond the desirable limits of BIS and WHO standards. Correlation matrix show a strong positive correlation existing between the calcium, magnesium, sodium, chloride and sulfate ions pointing out that groundwater in this region has been contaminated more by these components due to anthropogenic activities and over-exploitation. Hence, in the study region, suitable treatment of water is necessary before consumption, this is because maximum parts of the sampling points have a high WQI value.