Assessment of Quality of Groundwater in Parts of North-West Mandals of Krishna District, Andhra Pradesh, India

Abstract

Aims: To study the quality of groundwater in the selected mandals of Krishna district of Andhra Pradesh, India, in terms of drinking water quality parameters and to express the same in the form of water quality index that can be understood easily by the public. Study Design: The study includes i) collection of 20 groundwater samples from 5 different mandals, ii) Determination of 9 most significant quality parameters for all the water samples collected iii) Calculation of water quality index by incorporating data of multiple water quality parameters into a mathematical equation and iv) Assessment of water quality based on the water quality indices. Place and Duration of Study: Research Laboratory, Department of Chemistry, V. R. Siddhartha Engineering College, Vijayawada, Andhra Pradesh, India, during winter season between November and December 2015. Methodology: Water samples were collected from the sampling sites and nine quality parameters were determined based on the well-known standard procedures. Taking the drinking water quality standards proposed by Indian Council for Medical Research (ICMR) into consideration, the subindex values were calculated, from which the overall water quality indices were obtained. Results: Results revealed that pH ranged from 7.45 to 8.30, dissolved oxygen from 7.0 to 8.7 and turbidity from 0.01 to 0.92. These three parameters are found to be within the permissible limits in case of all the twenty samples. Further, concentration of chloride is within the permissible value of 250 ppm for 15 samples. The other parameters (alkalinity, hardness, TDS, EC and fluoride) exceeded the permissible limits in many locations. The total hardness values were found to be within the limit at eleven stations, while the excess values were obtained at remaining nine stations. Total hardness is below the permissible limit for all the four stations belonging to Vatsavai mandal. The sample from Mullapadu of Penuganchiprolu mandal exhibited highest values of chlorides, hardness, TDS and EC. The water quality index corresponding to the water from this station is found to be 36, the highest among all the twenty samples. Conclusion: The water quality index (WQI) values range from 5.4 to 36.0 in the present study. The acceptable limit of WQI is ≤ 50.0. Hence, it is concluded that groundwater from all the twenty stations is safe for domestic purpose. However, the sample from Mullapadu of Penuganchiprolu mandal exhibited the highest water quality index of 36 due to very high values of certain quality parameters.