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

C D Aju; Achu A L; Mohammed Maharoof P; M C Raicy; Rajesh Reghunath; Girish Gopinath

doi:10.1016/j.chemosphere.2024.141964

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

Chemosphere. 2024 Apr 12:357:141964. doi: 10.1016/j.chemosphere.2024.141964. Online ahead of print.

Authors

C D Aju¹, Achu A L², Mohammed Maharoof P³, M C Raicy⁴, Rajesh Reghunath⁵, Girish Gopinath⁶

Affiliations

¹ Department of Geology, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala, 695581, India; Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India; Department of Climate Variability and Aquatic Ecosystems, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, India.
² Department of Climate Variability and Aquatic Ecosystems, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, India. Electronic address: achu.geomatics@gmail.com.
³ PG Department of Applied Geology, GEMS Arts and Science College, Kadungapuram P.O, Ramapuram, Malappuram, Kerala, 679 321, India.
⁴ Hydrology and Climatology Research Group, Centre for Water Resources Development and Management (CWRDM), Kozhikode, 673 571, India.
⁵ Department of Geology, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala, 695581, India; International and Inter-University Centre for Natural Resources Management (IIUCNRM), University of Kerala, Thiruvananthapuram, 695 581, Kerala, India.
⁶ Department of Climate Variability and Aquatic Ecosystems, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, India.

PMID: 38615956
DOI: 10.1016/j.chemosphere.2024.141964

Abstract

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 (HI_Total) 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.

Keywords: Groundwater quality; Hazard index; Human health risk; Kerala; Nitrate contamination.