Nature Environment and Pollution Technology

G. Vennila ¹, T. Subramani ², L. Elango ³

Affiliations
1 Deptt. of Civil Engineering, K. S. Rangasamy College of Technology, Tiruchengode-637 215, T. N., IN
2 Department of Civil Engineering, Government College of Engineering, Salem-636 011, T.N., IN
3 Department of Geology, Anna University, Chennai-600 025, T.N., IN

Abstract

A detailed GIS based study on hydrochemistry of groundwater in Vattamalaikarai Basin, Tamil Nadu, India has been carried out to assess the quality of groundwater for determining its suitability for drinking purpose. Further, the spatial variation of various groundwater quality parameters over the basin has also been studied for January 2008. The area is underlained by crystalline rocks of peninsular gneissic complex, comprising of hornblende-biotite-gneiss and charnokite. Black, alluvial, and calcareous soils are major soil types in this region. Fifty nine groundwater samples spread over the basin have been collected from open and tube wells during January 2008. The physicochemical parameters have been compared with the standard guideline values as recommended by the WHO for drinking and public health. The abundance of major ions in groundwater is in the following order: Na⁺ > Mg²⁺ > Ca²⁺ > K⁺ = Cl^- > SO₄^2- > HCO₃^- > NO₃^- > CO₃^2-. TDS widely varied from 124 to 4270 mg/L with an average value of 1422 mg/L, and at 24 locations it exceeds the maximum allowable limit of 1500 mg/L leading to unsuitability of groundwater in nearly 40% of the total basin area. TDS exhibits good positive correlation with Na⁺, Mg²⁺ and Cl^-. Groundwater of the basin belongs to hard to very hard water category since the total hardness (TH) exceeds the permissible limit of 500 mg/L prescribed for drinking water. Nitrate concentration in groundwater also widely varies from 0 mg/l to 647 mg/L with an average value of 125 mg/L. Forty four well samples out of 59 exceed the maximum allowable limit of 45 mg/L (60% of the total basin area). Fluoride is also high (> 1.5 mg/L) in groundwater at 17 locations, which may cause dental fluorosis.

Keywords

Vattamalaikarai Basin, Groundwater Quality, Hydrochemistry, Drinking Water, Spatial Variation, GIS.

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S. Anandakumar ¹, T. Subramani ², L. Elango ³

Affiliations
1 Department of Civil Engineering, Kongu Engineering College, Erode-638 052, T. N., IN
2 Department of Civil Engineering, Government College of Engineering, Salem-636 011, T. N., IN
3 Department of Geology, Anna University, Chennai-600 025, T. N., IN

Abstract

The paper deals with the spatial variation of various groundwater quality parameters and their interrelationship in lower Bhavani River basin, Tamil Nadu, India. Biotite hornblende gneiss and charnockite are the basement rocks in this region. Groundwater occurs under water table conditions in the weathered mantle of crystalline rocks. Interpretation of the analytical results of fifteen groundwater samples spread over the basin indicates that groundwater of the area is mainly alkaline and hard in nature. Magnesium is the second dominant cation next to sodium, which is highly responsible for the higher total hardness in groundwater. Higher concentrations of geochemical parameters are noticed in the eastern part of the basin. Concentrations of geochemical parameters exceed the maximum allowable limits for drinking at few locations. Thus, it is suggested that groundwater of these locations need to be treated before using for drinking purposes. Groundwater of the area is, however, suitable for irrigation.

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