Open-Cast Coal Mining Operations Endanger Water Quality in India

Strategic Insights -

Research conducted in the South Indian peninsular region has found that open-cast coal mining operations significantly endanger water quality by introducing pollutants through mine drainage, airborne particles, and mining-related disturbances. The study, published in the Journal of Environmental Geochemistry and Health, evaluated the health hazards linked to potentially toxic elements (PTEs) contamination in water collected from lakes and discharge points adjacent to the Sathupalli open-cast coal mines in Telangana, India.

Key Takeaways:

  • The study found that the pH levels of the collected water samples from the study area varied, with Sathupalli centre mine water (SCW) exhibiting highly acidic conditions (2.2-4.9) with a mean value of 3.8, and other sites ranging from slightly acidic to alkaline (5.6-7.3) with a mean value of 6.6.
  • Potentially toxic elements (PTEs) such as Cr, Cd, As, Hg, and Pb were found in high concentrations, often exceeding BIS (Indian standard) permissible limits, particularly in SCW and Rajaria cheruvu (RC-Lake).
  • Geospatial analysis identified contamination hotspots, with indices like Heavy metal pollution index (HPI), Nemerov pollution index (NPI) and Heavy metal evaluation index (HEI) indicating severe pollution, and ecological risk index (ERI) values confirming high ecological impact across sites, especially SCW and RC.
  • The study found that SCW and RC exhibited the highest non-carcinogenic (HI 1) and carcinogenic (ILCR 1 x 10 ) risks, particularly for children via dermal and ingestion pathways.
  • Statistical methods such as Positive Matrix Factorization (PMF), correlation coefficients, and Principal Component Analysis (PCA) identified coal mining, especially acidic wastewater discharge, as the primary source of heavy metal pollution, with urban runoff and atmospheric deposition also contributing to contamination.

Statistics:

  • The pH levels of the collected water samples from the study area ranged from 2.2 to 7.3.
  • Potentially toxic elements (PTEs) such as Cr, Cd, As, Hg, and Pb were found in high concentrations, often exceeding BIS (Indian standard) permissible limits.
  • The Heavy metal pollution index (HPI), Nemerov pollution index (NPI) and Heavy metal evaluation index (HEI) values indicated severe pollution, with ecological risk index (ERI) values confirming high ecological impact across sites.
  • The study found that SCW and RC exhibited the highest non-carcinogenic (HI 1) and carcinogenic (ILCR 1 x 10 ) risks, particularly for children via dermal and ingestion pathways.

Sources:

  • Distribution and probabilistic human health and ecological risk assessment of potentially toxic elements in water, sediments and aquatic plants: a comprehensive study to understand the impacts of active coal mine on the lentic ecosystem. Environmental Geochemistry and Health, 2025;47(7):286.
  • Springer. Environmental Geochemistry and Health. www.springer.com; www.springerlink.com/content/0269-4042/