Sarkar et al. (2025) Characterizing seawater intrusion and groundwater vulnerability to salinization along the east coast of India

Identification

• Journal: Journal of Contaminant Hydrology
• Year: 2025
• Date: 2025-12-26
• Authors: Biplab Sarkar, Aznarul Islam, Amit Kumar, Swapan Talukdar, Md Nawaj Sarif, Akanksha Pandey, Kaustubh Lahiri, Sutapa Mukherjee, Abdur Rahman, S.K. Mafizul Haque, Abujar Rahaman
• DOI: 10.1016/j.jconhyd.2025.104829

Research Groups

• Department of Geography, Dr. Kanailal Bhattacharya College, West Bengal, India.
• Department of Geography, Aliah University, West Bengal, India.
• Department of Geography, Institute of Science, Banaras Hindu University, Uttar Pradesh, India.
• Department of Geography, Asutosh College, West Bengal, India.
• Rashtriya Raksha University, Lucknow Campus, Uttar Pradesh, India.
• Department of Geography, University of Calcutta, West Bengal, India.

Short Summary

This study evaluates seawater intrusion (SWI) across 37 districts on India's east coast, revealing that over 55% of groundwater samples are affected by salinization. The research identifies excessive groundwater extraction and permeable lithological layers as the primary drivers of landward saline water movement.

Objective

• To characterize the extent of seawater intrusion and assess groundwater vulnerability to salinization along the eastern coastal corridor of India using hydrochemical, geological, and anthropogenic extraction data.

Study Configuration

• Spatial Scale: Regional; covering 37 coastal districts across the states of West Bengal, Odisha, Andhra Pradesh, and Tamil Nadu, India.
• Temporal Scale: Annual (based on annual groundwater draft data and hydrochemical sampling).

Methodology and Data

• Models and Indices used: Hydrochemical Facies Evolution Diagram (HFE-D), Seawater Mixing Index (SMI), and Hotspot Analysis.
• Data sources: 1228 groundwater samples (analyzing 10 hydrochemical parameters), 15 lithologs for stratigraphic analysis, and annual groundwater draft data for irrigation, industrial, and domestic sectors.

Main Results

• Salinization Extent: 39.09% of samples were recorded as saline via HFE-D, and 55.09% of samples exhibited an SMI > 1, indicating widespread seawater intrusion.
• Regional Variation: West Bengal showed the highest vulnerability with 67.91% of samples having SMI > 1, followed by Tamil Nadu (63.61%), Andhra Pradesh (56.10%), and Odisha (32.49%).
• Hotspots: Significant groundwater salinization hotspots were identified specifically in the coastal regions of Odisha, Andhra Pradesh, and Tamil Nadu.
• Anthropogenic Drivers: High annual groundwater extraction rates—up to 7.94 × 10⁸ m³ for irrigation, 1.878 × 10⁷ m³ for industry, and 2.029 × 10⁸ m³ for domestic use—shift the hydraulic gradient landward.
• Geological Pathways: Lithological profiles indicate that fine sand and silt layers facilitate direct seawater seepage into coastal aquifers.

Contributions

• The study provides a large-scale, multi-state synthesis of seawater intrusion along the entire eastern coast of India.
• It integrates hydrochemical indices with detailed lithological data and sector-specific water extraction volumes to map salinization pathways and identify regional hotspots, offering a framework for coastal groundwater management.

Funding

• Not specified in the provided text.

Citation

@article{Sarkar2025Characterizing,
  author = {Sarkar, Biplab and Islam, Aznarul and Kumar, Amit and Talukdar, Swapan and Sarif, Md Nawaj and Pandey, Akanksha and Lahiri, Kaustubh and Mukherjee, Sutapa and Rahman, Abdur and Haque, S.K. Mafizul and Rahaman, Abujar},
  title = {Characterizing seawater intrusion and groundwater vulnerability to salinization along the east coast of India},
  journal = {Journal of Contaminant Hydrology},
  year = {2025},
  doi = {10.1016/j.jconhyd.2025.104829},
  url = {https://doi.org/10.1016/j.jconhyd.2025.104829}
}

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