Gedala Rupakumari, G.V.R. Srinivasa Rao and B. Kalyanaramu
Abstract
Groundwater is a critical freshwater resource sustaining domestic supply, agriculture, and ecological balance in semi-arid regions of India. In the Denkada region of Vizianagaram District, Andhra Pradesh, groundwater constitutes the primary source of potable water, necessitating a systematic assessment of its hydro-chemical characteristics and environmental suitability. This study evaluates groundwater quality using Comprehensive hydro-chemical analysis to determine its drinking suitability and to understand the governing geochemical processes influencing aquifer systems. A total of 792 groundwater samples were collected from twentytwo locations during pre-monsoon, post-monsoon and monsoon seasons (November 2018â October 2021). Fifteen physicochemical parameters were analyzed following APHA (2017) standard methods and comparedwith drinking water guidelines of the Bureau of Indian Standards (IS 10500:2012). Groundwater is slightly alkaline (pH 7.01â7.9), with TDS ranging from 275 to 3980 mg/l. Approximately 63.6% of samples exceeddesirable drinking water limits, indicating moderate to high salinity in several locations. Elevated hardness and magnesium concentrations further restrict potable suitability. Hydro-chemical facies identified using the Piper diagram indicate mixed CaâNaâHCO3 facies constitute 41% of the samples, followed by Ca-HCO3 facies (36%) and NaâCl facies (23%) water types, dominance of cation Na+ > Ca²+ > Mg²+ > K+ and anion HCO3â > Clâ > SO4 2â suggesting carbonate weathering and ion exchange as primary controlling processes. The observed spatial variability highlights concerns regarding groundwater salinisation. This study provides a scientific baseline for sustainable groundwater management, ecological protection, and long-term monitoring strategies to ensure safe drinking water supply in coastal aquifer systems of South India.