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

Abstract

Open-cast coal mining operations such as topsoil removal, coal extraction, and coal loading and transportation at site in the South Indian peninsular region significantly endanger water quality by introducing pollutants through mine drainage, airborne particles, and mining-related disturbances, impacting both surface and groundwater. This research evaluates 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 (SCCL-Singareni Collieries Company Limited) in Telangana, India. The results showed 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. PTEs such as Cr, Cd, As, Hg, and Pb were found in high concentrations, often exceeding BIS (Indian standard, Drinking water- specification -Second revision, In: IS: 10500. Bureau of Indian Standards, New Delhi, 2012) 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. SCW and RC exhibited the highest non-carcinogenic (HI > 1) and carcinogenic (ILCR > 1 × 10⁻⁴) risks, particularly for children via dermal and ingestion pathways. In contrast, Tamara Cheruvu (TC-Lake), Veshya Kanthala Cheruvu (VK-Lake), and Drain Discharge Water (DDW) showed lower but notable risks, emphasizing the urgent need for targeted mitigation in coal-impacted zones. 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. These results emphasize the importance for remediation efforts and continuous monitoring to mitigate environmental degradation and safeguard public health in mining-impacted regions.

Keywords: Chemometrics; Coal mine; Human and ecological risk; Pollution indices; Potentially toxic elements.