Characterisation of Groundwater Chemistry in an Eastern Coastal Area of Cuddalore District, Tamil Nadu

Abstract

The groundwater quality detoriation due to various geochemical processes like saline water intrusion, evaporation and interaction of groundwater with brines is a serious problem in coastal environments. Understanding the geochemical evolution is important for sustainable development of water resources. A detailed investigation was carried out to evaluate the geochemical processes regulating groundwater quality in Cuddalore district of Tamilnadu, India. The area is entirely underlined by sedimentary formations, which include sandstone, clay, alluvium, and small patches of laterite soils of tertiary and quaternary age. Groundwater samples were collected from the study area and analyzed for major ions. The electrical conductivity (EC) value ranged from 962 to 11,824 µS/cm, with a mean of 2802 µS/cm. The hydrogeochemical evolution of groundwater in the study area starts from Mg–HCO3 type to Na–Cl type indicating the cation exchange reaction along with seawater intrusion. The Br/Cl ratio indicates the evaporation source for the ion. The Na/Cl ratios indicate groundwater is probably controlled by water-rock interaction, most likely by derived from the weathering of calcium–magnesium silicates. The plot of (Ca+Mg) versus HCO3 suggests ions derived from sediment weathering. The plot of Na+K over Cl reflects silicate weathering along with precipitation. Gibbs plot indicates the dominant control of rock weathering. Factor analysis indicates dominance of salt water intrusion, cation-exchange and anthropogenic phenomenon in the study.

Geochemical signatures of groundwater in the coastal aquifers of Thiruvallur district, south India

“…Sodium and chloride show a good correlation (Fig. 7), indicating groundwater is probably controlled by water-rock interaction, most likely derived from the weathering of calcium-magnesium silicates, chiefly from calcite, plagioclase, gypsum and feldspar (Srinivasamoorthy et al 2011).However, increased concentration of HCO 3 compared to Na concentration (Fig. 8) in groundwater suggests that silicate weathering also occurs (Fisher and Mullican 1997).…”

“…Seawater intrusion is one of the most common problems in almost all coastal aquifers around the globe Goldenberg 1997, 1998;Sivakumar and Elango 2008;Chidambaram et al 2009;Mondal et al 2010Mondal et al , 2011Srinivasamoorthy et al 2011). This phenomenon can be explained by a variety of conditions such as gentle coastal hydraulic gradients, tidal and estuarine activity, sea level rises, low infiltration, excessive withdrawal and local hydrogeological conditions (Sarma et al 1982;Longe et al 1987;Rajmohan et al 2000;Barret et al 2002;Saxena et al 2004;Kacimov et al 2009).…”

Chemistry and quality of groundwater in a coastal region of Andhra Pradesh, India

“…Mondal et al (2011) described hydrochemical characteristics of the coastal aquifer from Tuticorin, Tamil Nadu. Srinivasamoorthy et al (2011) found rock-weathering, ion-exchange and anthropogenic processes as dominant factors on groundwater quality in an eastern coastal area of Cuddalore district. Sarath Prasanth et al (2012) evaluated groundwater quality and its suitability for drinking and agricultural use in the coastal stretch of Alappuzha District.…”

Geochemical evolution of groundwater in the Western Delta region of River Godavari, Andhra Pradesh, India

“…in the groundwater due to input from the weathering of Ca-Mg minerals (calcite, gypsum and plagioclase feldspar present in the sediments (Cerling et al 1989;Fisher and Mullican 1997;Srinivasamoorthy et al 2011). The remaining water samples (4 %) fall above the uniline (1:1) ions is caused by reverse ion exchange process.…”