Evaluation of Shallow Ground Water Quality: A Case Study for a Coal Mining Environment (East Bokaro Coalfield) of Damodar Valley, India

Abstract

Thirty shallow ground water (Dug well) samples were collected from a coal mining environment to assess the water quality status for drinking suitability. The pH, electrical conductivity, total dissolved solids, turbidity, total hardness, dissolved silica and total alkalinity in the ground water samples ranged from 6.91 to 8.44, 318 to 2408 µS/cm, 223 to 1710 mg/L, 0.3 to 7.9 NTU, 42 to 553 mg/L, 8.5 to 19 mg/L and 52 to 656 mg/L, respectively. The major anions such as F⁻, Cl⁻, NO₃⁻, SO₄²⁻and HCO₃⁻ ranged from 0.28 to 1.5 mg/L, 8.9 to 198 mg/L, 0.8 to 106.2 mg/L, 9.9 to 140.2 mg/L and 42.8 to 517.5 mg/L, respectively. The major cations such as Ca²⁺, Mg²⁺, K⁺ and Na⁺ were analyzed and found within the desirable limits, except for Mg²⁺ and Ca²⁺. The overall study showed that the higher values found in some of the samples were mainly due to the higher values of total dissolved solids, HCO₃⁻, total hardness, Mg²⁺ and total alkalinity. The other parameters are all within the maximum permissible limit of the Bureau of Indian Standards (BIS) and World Health Organization (WHO) drinking water standards. Moreover, the Water Quality Index (WQI) was calculated to provide a better understanding of the overall water quality for the coal mining environment. The WQI ranged from 44.6 to 127.4, which indicated good to very poor status of water quality.