Spatiotemporal variability and source apportionment of the ionic components of groundwater of a mineral-rich tribal belt in Bastar, India

This study illustrates the spatiotemporal variability pattern and source-routes of major ionic contaminants of groundwater in mineral-rich tribal belt of Bastar, India. Around 160 groundwater samples from 95 sampling sites were collected during the pre- and post-monsoon periods using a pooled study design. These samples were then chemically analyzed for pH, TDS, EC, TH, Mg²⁺, Ca²⁺, Na⁺, K⁺, HCO³⁻, F⁻, NO₃ ⁻, Cl⁻, and SO₄ ²⁻. Ionic species exhibited distinct spatial variability patterns at the temporal scale of pre- and post-monsoon periods. Two source apportionment modeling techniques (PCA and PMF 5.0), based on factor analysis, were applied to investigate the source-routes of ionic components in groundwater. Three major contributing source-routes were identified for the ionic components: 1) mineral dissolution (~25%), 2) agricultural activities (30–36%), and 3) rainwater percolation (40–45%). The suitability of groundwater for irrigation purposes was also evaluated by analyzing the electrical conductivity, sodium percentage, and sodium adsorption ratio. The study will serve as an important reference for understanding groundwater chemistry and improving sustainable groundwater management planning in the tribal belt of the Bastar region.