Hydrogeochemical processes and influence of seawater intrusion in coastal aquifers south of Chennai, Tamil Nadu, India

• Published in: Environmental science and pollution research international 2018-03, Vol.25 (9), p.8989-9011
• Main Authors: Kanagaraj, G., Elango, L., Sridhar, S. G. D., Gowrisankar, G.
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Aquatic Pollution; Aquifers; Atmospheric Protection/Air Quality Control/Air Pollution; Backwaters; Barriers; Chemical analysis; Coastal aquifers; Coastal zone; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental impact; Environmental Monitoring - methods; Environmental science; Fresh Water - analysis; Geochemistry; Geophysics; Groundwater; Groundwater - analysis; Gypsum; Halites; Human influences; Hydrogeochemistry; India; Intrusion; Ions - chemistry; Isotopes; Isotopes - chemistry; Minerals; Monsoons; Research Article; Saline water intrusion; Salinity; Salinization; Salt flats; Saturation index; Seawater; Stable isotopes; Sulfates; Waste Water Technology; Water analysis; Water Management; Water Pollution Control; Water sampling; Water Wells; Weathering
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-0910-5

Seawater intrusion promotes the salinity of groundwater, and it poses a great environmental impact on a global scale. The present study was carried out to determine the hydrogeochemical processes and influence of seawater intrusion in the coastal aquifers using geophysical, geochemical, and stable isotope techniques. The true resistivity value ranges from 0.5 to 8008.5 Ω-m which has been measured using vertical electrical sounding (VES) based on the Schlumberger method. About 33 groundwater samples were collected during post-monsoon (POM) (January 2012) and pre-monsoon (PRM) (June 2012) seasons from open and bore wells and were analyzed for major ions and stable isotopes. EC, Na + , and Cl − were high in groundwater of wells near salt pan, the Buckingham Canal, and backwater regions. Around 45% of the groundwater of this study area is of Na + -Cl − type due to salinisation. Reverse ion exchange and silicate weathering are the dominant processes controlling the geochemistry of groundwater. Saturation indexes (SI) of halite (SI halite ) and gypsum (SI gypsum ) versus sulfate show an increasing trend line from > 0 to