Emerging nitrate contamination in groundwater: Changing phase in a fast-growing state of India.

The consumption of nitrate-contaminated groundwater is often associated with potential health risks, particularly in children. This study aimed to assess the hydrochemistry and nitrate contamination in groundwater of Kerala state, India for the years 2010 and 2018 and evaluate the potential human health risks due to nitrate exposure in adults, and children through oral ingestion and dermal contact pathways. Nitrate-contaminated zones were identified by spatial mapping of nitrate concentration based on groundwater quality data of 324 wells. Groundwater is typically acidic to slightly alkaline, and the electrical conductivity (EC) varied from 33 to 1180 µS/cm in 2010 and 34.6-2500 mg/L in 2018 indicating a noticeable increase over the years. Most samples fall within low salt enrichment category. The nitrate concentration in groundwater varied from 0 to 173 mg/L with a mean of 15.4 mg/L during 2010 and 0 to 244 with a mean of 20.3 mg/L during 2018. Though nitrate concentrations show uneven spatial distributions due to both natural and anthropogenic sources, the spatial clustering of higher concentrations remains almost same in both periods. In 2010, non-carcinogenic risk, as measured by Health Index Total (HITotal) values in groundwater for the investigated region, ranged from 0.005 to 4.170 (mean of 0.349) for males, 0.005 to 4.928 (mean of 0.413) for females, and 0.008 to 7.243 (mean of 0.607) for children, while in 2018, the corresponding values varied from 0.001 to 5.881 (mean of 0.501) for males, 0.002 to 6.950 (mean of 0.592) for females, and 0.003 to 10.215 (mean of 0.870) for children, indicating a substantial increase in risk, for females and children. Greater health risk is observed in children during both the periods. The findings emphasize the need for proper water quality management, especially in regions with higher vulnerability to nitrate pollution, to safeguard human health and well-being.

An integrated groundwater resource management approach for sustainable development in a tropical river basin, southern India.

Evaluation of aquifer potential is essential, as the potable water demand has increased globally over the last few decades. The present study delineated different zones of groundwater potential and groundwater quality of the Kallada River basin (KRB) in southern India, using geo-environmental and hydrogeochemical parameters, respectively. Geo-environmental variables considered include relative relief, land use/land cover, drainage density, slope angle, geomorphology, and geology, while hydrogeochemical parameters include pH, electrical conductivity (EC), Cl-, Fe3+, and Al3+ concentrations. Analytical hierarchy process (AHP) was used for categorizing groundwater potential and quality zones. Nearly 50% of KRB is categorized as very high and high groundwater potential zones, occupying the western and midland regions. The central and west-central parts of KRB are characterized by excellent groundwater quality zones, while the eastern and western parts are characterized by good and poor groundwater quality zones, respectively. By integrating the groundwater potential and groundwater quality, sustainable groundwater management is observed to be necessary at about 54% of the basin, where site-specific groundwater management structures such as percolation ponds, injection wells, and roof water harvesting have been proposed using a rule-based approach. This integrated groundwater potential-groundwater quality approach helps policymakers to implement the most suitable management strategies with maximum performance.