Assessment of Physicochemical Parameters of Groundwater in Various Districts of Tamil Nadu

Abstract

Groundwater is one of the most important sources of drinking water for human populations. Rapid urbanization, industrialization, and agricultural activities have significantly affected groundwater quality in many regions. This study focuses on the assessment of groundwater quality by evaluating various physicochemical parameters to determine its suitability for domestic and agricultural purposes. Groundwater contamination occurs when harmful substances such as industrial chemicals, fertilizers, pesticides, sewage, and landfill leachate enter underground aquifers. These pollutants alter the natural characteristics of water and reduce its quality. Once groundwater becomes polluted, it is very difficult to restore due to the slow movement of water beneath the Earth\'s surface. In this study, groundwater samples were collected from six different locations in Tamil Nadu. The collected samples were analyzed for physical and chemical parameters such as colour, odour, temperature, turbidity, total hardness, chloride, fluoride, and residual chlorine. These parameters help determine water quality and suitability for drinking purposes. The results showed variations in groundwater quality among sampling locations. Some samples showed higher hardness and chloride levels due to mineral dissolution and environmental conditions. However, most parameters were within acceptable limits. Regular monitoring of groundwater quality is necessary to ensure safe water supply and protect water resources for future generations.

Introduction

1. Overview

• Water pollution occurs when harmful substances contaminate water bodies, affecting physical, chemical, and biological quality.

• Major sources include domestic sewage, industrial effluents, agricultural runoff, solid waste, oil spills, mining, and atmospheric deposition.

• Polluted water can cause waterborne diseases (cholera, typhoid, dysentery), affect aquatic ecosystems, reduce dissolved oxygen, and lead to eutrophication from excess nutrients.

• Groundwater pollution is caused by contaminants seeping from natural minerals or human activities like agriculture, industrial waste, landfill leachate, and untreated sewage, posing long-term health risks.

2. Materials and Methods

• Sampling Locations: Groundwater collected from six districts of Tamil Nadu: Madurai, Thiruvannamalai, Coimbatore, Kodaikanal, Karur, and Sivagangai.

• Sample Collection: 1-litre samples collected in clean polyethylene bottles.

• Analysis:

  • Physical: Colour, odour, temperature, turbidity.

  • Chemical: Total hardness, chloride, fluoride, residual chlorine using standard laboratory methods.

Tests Conducted:

1. Total Hardness: EDTA titration to measure Ca²? and Mg²? ions; results expressed in mg/L as CaCO?.

2. Fluoride: Colour change method using Zirconium alizarin complex; compared against a standard chart.

3. Chloride: Titration with chloride reagents; concentration calculated in mg/L.

4. Residual Chlorine: Colour comparison using standard residual chlorine chart; indicates disinfection level.

3. Results

• Physical Examination: All samples were colourless and odourless; temperature varied slightly by location.

• Chemical Analysis:

  • Total Hardness: Samples 1–5 showed very high hardness (850–1100 mg/L), while Sample 6 was lower (~200 mg/L), likely due to dissolved calcium and magnesium from mineral-rich rocks.

  • Residual Chlorine: Only Sample 3 had detectable chlorine (~0.5 mg/L), indicating proper disinfection; others had nearly zero.

  • Chloride Content: Varied widely; Sample 1 highest (~250 mg/L), Sample 6 lowest (~50–60 mg/L). High levels may result from salt-rich soils, sewage, agricultural runoff, or industrial discharge.

  • Fluoride Content: Showed noticeable variation across samples, reflecting local geological and environmental factors.

Conclusion

The groundwater analysis study reveals that the quality of groundwater varies depending on geological formation, human activities, and environmental conditions. The quality of ground water samples collected from 6 different locations around Tamilnadu was analysed and studied. The physicochemical parameters such as pH , total hardness, chloride, residual chlorine, fluoride were analyzed . The results indicates that most of the parameters are within the acceptable range for domestic purposes, while a few samples show slight variations due to agricultural runoff, industrial discharge, or natural mineral dissolution. Increased hardness levels in some areas suggest the presence of dissolved salts and minerals. Overall, the groundwater in the study area is found to be suitable for irrigation purposes, with minor treatment recommended in areas where certain parameters exceed permissible limits. Continuous monitoring and proper groundwater management practices are essential to prevent further contamination and to ensure safe and sustainable use of groundwater resources.

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Copyright

Copyright © 2026 Anusuya Venkatachalam, Brindha Anandhan, Subashini Arockiyam. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.