Vol.:(0123456789) 1 3 International Journal of Energy and Water Resources https://doi.org/10.1007/s42108-022-00223-y ORIGINAL ARTICLE Assessment of groundwater suitability in Tiruchirappalli district, Tamil Nadu, India, based on Water Quality Index (WQI) D. Shanthi 1  · K. Kalaivanan 2  · K. Sankar 2 Received: 7 March 2022 / Accepted: 10 November 2022 © The Author(s), under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University 2022 Abstract In Tamil Nadu, India, the Tiruchirappalli district is located in the central part of the region. Hard rock formations from the Archaean to sedimentary formations from the Quaternary era are found within Tiruchirappalli district. The entire study area can determine hard rock and sedimentary rock regions. The groundwater system must be assessed for sustainability in response to population growth and agriculture intensifcation. During the Southwest Monsoon (SWM) season, 90 groundwater samples were collected and analyzed for major cations and anions. In the study area, the cation abundance of groundwater samples is arranged as Na 2+ > Ca 2+ > Mg 2+ > K + and major anions in this research region are distributed in the following order of relative abundance: HCO 3 − > SO 4 2− > Cl − > NO 3 − . Water facies on the Piper plot include Ca–HCO3, Ca–Cl, Na–Cl, Na–HCO 3 , mixed Ca, Na–HCO 3 , and mixed Ca, Mg–Cl groundwater samples. The Durov diagram represents underground water's hydro-geochemical mechanisms and chemical exchange processes. Reverse ion exchange mechanisms and human origin mixture via rainfall recharge are represented in the research region. The plot of Gibbs implies that a rock dominance process precedes weathering of rock-forming components. Drinking and irrigation guidelines show that most water evaluated is safe for human consumption. Ion exchange, agricultural runof, and human waste all infuence water chemistry. Most Water Quality Index (WQI) samples fall into the excellent-to-good water category. Keywords Hydro-geochemistry · Drinking · Irrigation utility · WQI Introduction Water is crucial to the survival of all species in the ecosystem. Shallow groundwater quality is affected by human activity. The water quality of rivers, lakes, coastal lagoons, etc., is deteriorating due to human activities, climate change, and rising health concerns. Water quality must be monitored to preserve the environment, ensure sustainability, and predict environmental changes. Human activities and geological activity generally influence groundwater quality (Adimalla & Qian, 2019; Chaurasia et al., 2021; Sunitha et al., 2022; Sutradhar & Mondal, 2021). Due to human activities, particularly those associated with the industrial and green revolutions, the biological balance has been disrupted, resulting in an increase in pollution from untreated industrial efuents and agricultural wastes (Rao et al., 2021; Roy et al., 2018; Sargazi et al., 2021; Silva et al., 2021). The quality of groundwater is also afected by various geogenic processes. The quality can vary in short distances within the area under study due to highly localized factors like topography and lithology (Chen et al., 2019; Coyte et al., 2019; Kawo & Karuppannan, 2018; Subba Rao & Chaudhary, 2019). Several factors afect the amount, including rainfall, groundwater movement, ion content, ion exchange, environment, and the recharge and discharge cycle variation. The following factors determine the groundwater geochemistry: (i) rock composition and soil type (ii) Water is abundant in the summer months, but it is scarce during the monsoon (iii) Aquifer interchange caused by diferential pressures due to continuous withdrawals (iv) surface water contamination contaminating groundwater (v) Poorly designed wells that allow fowing water to enter directly and (vi) the degree to which water is being used. * K. Kalaivanan kalai.geo87@gmail.com D. Shanthi roshanthidr@gmail.com 1 Department of Geography Government Arts College, Trichy, Tamil Nadu 620 022, India 2 Department of Industrial and Earth Sciences, Tamil University, Thanjavur, Tamil Nadu 613 010, India