Assessment of the hydrogeochemistry of shallow water aquifers using corrosion indices and geospatial techniques in the regions of the Brahmaputra river basin, India

The present study was conducted to assess the groundwater hydrogeochemistry of the Majuli River Island in the Brahmaputra river basin. Forty-three groundwater samples were collected from shallow aquifers from different sites in the Majuli River basin, and various physicochemical parameters of the samples were analyzed. The study showed that nearly 27%, 79.06%, 88.37%, and 74.41% of groundwater samples had higher nitrate, total hardness, iron, and manganese content, respectively, than the acceptable limits of the Bureau of Indian Standards (BIS) for drinking water. The water quality index revealed that 72% of samples were not at all suitable for human drinking purpose. The piper trilinear plot showed that the groundwater could be classified as mixed water, i.e., Ca–HCO₃, Ca–Mg–HCO₃ and Mg–Ca–HCO₃, based on the cation and anion concentration. For analyzing the corrosiveness and scaling potential of the groundwater, the Langelier saturation index (LSI), Ryznar stability (RSI), Puckorius scaling (PSI), Larson Skold index (LaI), and chloride sulphate mass ratio (CSMR) were computed. The Ryznar index value of 70% collected groundwater samples was found to be more than 7.0, depicting significant corrosion towards the groundwater. Similarly, 90.69% samples had PSI value >6.5, representing a tendency for corrosion. A total of 70% and 95.34% of the groundwater samples were corrosive in nature based on the LaI and CSMR index values, respectively. Therefore, the indices revealed that that majority of groundwater samples of the Majuli River Island were corrosive in nature due to its non-alkaline characteristic and high iron content in the groundwater. The groundwater of the Majuli River Island may cause a detrimental impact on the domestic and industrial water quality and water distribution systems.