Aquifer salinization: A groundwater appraisal of northeast coast of Odisha using water quality index (WQI) and geospatial interpretation

Abstract

Groundwater is an important source of drinking water supply in the northeast coastal tract of Odisha. Salinization of aquifer is one of the major problems in the coastal aquifers. An attempt has been made to analyze the hydro-geochemistry of groundwater and its suitability through statistical and geospatial data interpretation. A total 60 water samples are collected from coastal villages of Balasore Sadar and Remuna block of the Balasore district of Odisha during pre-monsoon period and analyzed. The water quality parameters like pH, electrical conductivity, total dissolved solid, carbonate, bicarbonate, calcium, magnesium, potassium, sulphate, chloride, fluoride was analyzed using standard analytical procedure (APHA, 2012) for determination of salinity and groundwater facies. The analytical results are compared with WHO and BIS drinking water quality standard. The hydro chemical facies of the study area are determined based on Schoeller's Plot and Langelier-Ludwig diagrams. Scholler's diagram revealed the dominance of Na + cation as well as Clanion along the coastal tract. And dominance of Ca 2+ , Mg 2+ and HCO -3 in other localities. Stiff diagrams' results are consistent with Schoeller's plot and Langelier-Ludwig diagram showing three types of groundwater. The result reveals that, Ca 2+ -HCO 3 type gradually changes to Na + -Cltype through Ca 2+ -Mg 2+ -Cltype mixed waters, which might be an indication of change of hydrogeological conditions. The Stiff diagram shows that the water type along the coast is sodium-chloride, which suggests the intrusion of saline water into the deeper aquifer from adjacent seawater. The classification of water based on water quality index (WQI) results majority of the water samples falling under good category and suitable for drinking except samples of Rupsa, Hasanpur, Haldipada bazar, Chakulia (Baharde), Parikhi, Remunabasant market-2, Majhikia and Mala which show poor WQI. Fluoride concentrations also found in some samples above the permissible limit. Iso-concentration maps represent the spatial distribution of concentration of different parameters throughout the study area.