Decadal Shifts in Groundwater Chemistry and Associated Health Risks in the Most Fertile Land of Central India

Abstract

This study investigates spatiotemporal groundwater quality dynamics in the Malwa region (the most fertile land of Central India) of Madhya Pradesh and Rajasthan, India, using modified Mann-Kendall (MMK) trend analyses and Sen's slope on a comprehensive data set spanning 2000-2021. Hierarchical cluster analysis revealed distinct hydrogeochemical zones, with Piper and Wilcox diagrams indicating a predominance of calcium-magnesium-bicarbonate (Ca2+-Mg2+-HCO3-) water type and increasing salinity risks over time. MMK tests have identified statistically significant trends for various pollutants across the study area, at 95% confidence limit, across several districts. Meanwhile, the major ions have demonstrated spatial variability in the trends, which can be attributed to hydrogeological heterogeneity and anthropogenic influences. Human health risk (HHR) assessments revealed concerning noncarcinogenic risks, with 35.3% and 88.2% of districts exceeding hazard index thresholds for adults and children, respectively, by 2021. Ingestion contributed 98.4%-99.1% of the total risk, with nitrate posing a significantly higher hazard than fluoride. The study has detailed the causes of pollution, trends, long-term effects, and possible methods of groundwater treatment. Geospatial analysis has revealed significant correlations between groundwater contamination and factors such as population density, fertilizer consumption, and deforestation, which emphasizes the need for integrated water resource management. The study highlights the urgent need for targeted interventions, sustainable agricultural practices, and conservation measures to mitigate the decline in groundwater quality within the Malwa region. � 2026 American Society of Civil Engineers.