To understand the characteristics of stable isotopes and trace elements in groundwater of Thirumanimuttar sub-basin, Tamil Nadu, India

Thirumanimuttar River is the only ephemeral stream passing through the heart of the Salemcity and flows towards southwest and joins river Cauvery in the southern region of Kuduthurai at near Paramathi Vellur forms the spinal cord for urban development. A number of industrial units including dyeing/bleaching and sago industries were located within the core zone. The industrial effluent and sewage water disposal by conversion of natural streams and water bodies as sewer drains. An attempt has been made to study the characteristics of stable isotopes and trace elements in groundwater of Thirumanimuttar sub-basin. Hence, thirty-four groundwater samples were collected for stable isotope [Oxygen (18O), Hydrogen (2H or Deuterium)] and trace element studies. The study reveals that the groundwater samples undergone some evaporation prior to infiltration. The d-excess of the groundwater were varied between -4.89 to 10.08 ‰ indicating that the water undergone strong evaporation during recharge into the local groundwater system. The trace element study indicates that some trace metals such as Al, Ni and Pb exceeds the acceptable limit. The spatial distribution map shows higher concentration of Cr is increased from north to south due to the textile dyeing units were located around in the region

Hydrochemical characterization and quality appraisal of groundwater from Pungar sub basin, Tamilnadu, India

The Pungar sub basin is located in the central part of South India. The geology is mainly composed of Archean crystalline metamorphic complexes. Increased population and intensive agricultural activity make it imperative to assess the quality of the groundwater system to ensure long-term sustainability of the resources. A total of 87 groundwater samples were collected from bore wells for two different seasons, viz., Pre monsoon and Post monsoon and analyzed for major cations and anions. Semi-arid climate, high evaporation rate and nutrient enrichment are the key features for EC enrichment. HigherNO3- and Cl− were observed in groundwater samples. The sources of Ca2+, Mg2+, Na+ and K+ are from silicate weathering process. The facies demarcation suggests base exchanged hardened water. Gibbs plot suggests chemical weathering of rock forming minerals along with evaporation. The plot of (Ca2+ + Mg2+) versus (SO42-+HCO3-) suggests both ion exchange and reverse exchange processes. The plot of (Na++K+) versus TZ+ shows higher cations via silicate weathering, alkaline/saline soils and residence time. The disequilibrium index for carbonate minerals point out influence of evaporation and silicate minerals favor incongruent dissolution. Mineral stability diagrams signify groundwater equilibrium with Kaolinite, Muscovite and Chlorite minerals. Comparison of groundwater quality with drinking standards and irrigation suitability standards proves that majority of water samples are suitable for drinking purpose. In general, water chemistry is guided by complex weathering process, ion exchange and influence of agricultural and sewage impact

A study on hydrochemical elucidation of coastal groundwater in and around Kalpakkam region, Southern India

The chemical composition of 29 bore well water samples throughout the Kalpakkam region, South India, was determined to identify the major hydrogeochemical processes and the suitability of groundwater for domestic and irrigation purposes. The hydrochemical data were analyzed with reference to World Health Organization (WHO) standards and their hydrochemical facies were determined. The Piper plot shows that most of the groundwater samples fall in the field of mixed calcium–sodium–bicarbonate type followed by sodium–chloride, calcium–bicarbonate and mixed calcium–magnesium–chloride water types. The concentration of total dissolved solids exceeds the desirable limit in about 14% of samples; alkalinity values exceed the desirable limit in about 34% of the samples. The concentration of sulphate is well within the desirable limit at all the locations. The dominance of various heavy metals in the groundwater followed the sequence: Zn > Fe > Mn > Cu > Ni > Pb > Cr > Cd. Among the metal ions, the concentration of chromium and cadmium are within the permissible limit. Data are plotted on the US Salinity Laboratory diagram, which illustrates that most of the samples fall in the field of high salinity and low sodium hazard, which can be used to irrigate salt tolerant and semi-tolerant crops under favorable drainage conditions. Based on the analytical results, chemical indices like sodium adsorption ratio and residual sodium carbonate were calculated which show that most of the samples are good for irrigation

Major ion chemistry and identification of hydrogeochemical processes controlling groundwater in and around Neyveli Lignite Mines, Tamil Nadu, South India

Groundwater geochemistry was studied in and around the Neyveli lignite mining region of Tamil Nadu, India. Representative groundwater samples (168) were collected from bore wells during June 2004, October 2004, January 2005, and March 2005 to broadly cover seasonal variation. Higher electrical conductivity values were observed in the southeastern and southwestern part of the study area. During the southwest monsoon (June) and postmonsoon (January) seasons, bicarbonate + chloride dominated the anions, with few representations for sulphate. Sodium + potassium were the dominant cations in all the seasons except in summer (March). The data reveals that the region is a complex hydrogeochemical system with proportional interplay of ions from leaching of ions, ion exchange, agricultural return flow, and stagnant waters. The influence of mine waters and weathering of minerals varies according to the season and spatial distribution of the sources. The water quality can be used for drinking and irrigation, except in a few locations

Hydrogeochemistry Of Thirumanimuttar Basin: An Indication Of Weathering and Anthropogenic Impact

A total of 148 groundwater samples were collected from bore wells from Thirumanimuttar sub-basin for two seasons to identify major geochemical process activated to alter groundwater chemistry. The study revealed relationships with the lithology and anthropogenic process. Groundwater in the region was dominated by Na - Ca - Mg and Cl and HCO3 types. The (Ca +Mg) Versus TZ+ plot for both seasons reveals higher Ca and Mg due to leaching due to silicate mineral weathering from aquifer matrix of the study area. The plot for (Na + K) versus TZ+ indicates weathering process of both alkali and alkali earth from feldspars along with additional sources like contribution from alkali/saline soil and residence time. Saturation index of silicate, carbonate and fluoride minerals indicates oversaturation and equilibrium state and sulfate minerals were at undersaturated state during both the seasons. Lithology and Anthropogenic activity plays a significant role in controlling groundwater chemistry of the study area