Geochemical processes and groundwater quality assessment in the Yamuna-Hindon interfluve region of Bagpat district, Western Uttar Pradesh, India

The present research work aims to understand the geochemistry of groundwater resources of the Yamuna—Hindon interfluve region of Bagpat district, Western Uttar Pradesh, India. The region is a part of Indo-Gangetic belt, one of the world's most fertile and intensely farmed areas. To investigate the geochemical processes governing groundwater quality, a total of 105 groundwater samples were collected during pre-monsoon season and analyzed for various physico-chemical parameters, namely, pH, electrical conductivity (EC), total dissolved solid (TDS), total hardness (TH), turbidity, major anions (HCO₃⁻, SO₄²⁻, F⁻, Cl⁻, NO₃⁻)_, cations (Ca²⁺, Mg²⁺, Na⁺, K⁺) following the methods outlined in the American Public Health Association (APHA). The dissolved heavy metals (Fe, Mn, Zn, Pb, Cu, Cr, Ni, As, Se, Co, Cd and Al) in groundwater were analyzed by ICP-MS following the instrument manual. The analysis results revealed that the groundwater is pre-dominantly neutral to mildly alkaline in nature. The major cation chemistry majorly followed the occurrence pattern of Na⁺ > Mg²⁺ > Ca²⁺ > K⁺, while for anions it was HCO₃⁻ > Cl⁻ > SO₄²⁻ > NO₃⁻ > F⁻. The data plotted on Piper triangular diagram indicated that Ca²⁺-Mg²⁺-HCO₃⁻ and Na⁺-K⁺-HCO₃⁻-Cl⁻ were major hydrogeochemical facies. Weathering of rock-forming minerals mainly governed the groundwater geochemistry in this region, although part of the cations associated with Cl⁻, F⁻ and NO₃⁻ may originate from anthropogenic sources. TDS, TH, turbidity and F⁻ were identified as the major parameters that violated the prescribed limits for drinking water. Most of the heavy metals were found within the drinking water prescribed limits except for Fe, Mn, Al and Se. Elevated salinity, %Na, and magnesium hazard (MH) at certain sites limit its suitability for agricultural use. The assessment of selected organochlorine and organophosphorus pesticides in five samples indicated presence of lindane, β-endosulfan and DDT isomers in few samples. However, a detailed investigation of possible pesticide contamination in this intensive agriculture area is required before drawing any final conclusions.