Hydrogeochemical characterization and seawater intrusion assessment in coastal aquifers of SW Bangladesh.
- 2026-04-16
- Environmental geochemistry and health 48(7)
- PubMed: 41989487
- DOI: 10.1007/s10653-026-03162-3
Study Design
- Methods
- Hydro-chemical and statistical analysis, including Piper and Gibbs diagrams, Pearson correlation, Wilcox plot, spatial analysis, heat map and seawater fraction (f_sw)
- Funding
- Unclear
Seawater intrusion poses a significant threat to groundwater resources worldwide, particularly in the coastal regions of Bangladesh. The research evaluated the seawater intrusion (SWI) and groundwater salinization in the coastal aquifers of Khulna and Shatkhira districts, Bangladesh to overcome the knowledge gap on the integrated hydrochemical and spatial assessment of seawater intrusion in the coastal areas. Hydro-chemical and statistical analysis, including Piper and Gibbs diagrams, Pearson correlation, Wilcox plot, spatial analysis, heat map and seawater fraction (fsw) were generated to depict lateral extent of SWI in the southwestern part of Bangladesh. The results revealed significant levels of salinity intrusion in coastal aquifers. Groundwater exhibited high TDS and EC contents with Na+, Ca2+, Mg2+, K+, Cl- and F- concentrations which exceeded WHO standards. Approximately 87.5% of water samples were unsuitable for drinking purposes based on EC classification, while 50% showed unsuitability for irrigation. Salinity in the groundwater ranged widely from 0.04516 to 5.11458 ppt. Piper diagrams identified predominant hydro-chemical facies as Na+ + Cl- type, with chloride concentrations ranging from 25 to 2831.13 mg/L, indicating salinity intrusion. Gibbs diagrams confirmed rock-water interaction and seawater mixing. An increasing fsw trend seaward indicated more influence of SWI over GW aquifers closed to shoreline and inverse Simpson ratio highlighted slightly to injuriously saline categories, with significant chloride concentrations indicating potential salinity risks. The study concluded that the seawater intrusion is occurring in the coastal aquifers of Khulna and Satkhira districts of Bangladesh while significantly reducing the suitability of groundwater for drinking and irrigation purposes. Our findings recommend governments' intervention for sustainable groundwater monitoring and management along with policy advancement to protect coastal aquifers under climate change and anthropogenic pressures.
Research Insights
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