Evaluation of physical and heavy metal contamination and their distribution in waters around Maddhapara Granite Mine, Bangladesh

Abstract

The Maddhapara Granite Mine is a significant contributor to Bangladesh's economy, causing considerable environmental concern due to the discharge of untreated mine water. This water presents possible hazards to local ecosystems, agriculture, and public health. For this investigation, we obtained water samples from 15 distinct places in the vicinity of the granite mine. A comprehensive analysis of the physicochemical properties was conducted including pH, turbidity, electrical conductivity (EC), total dissolved solids (TDS), and dissolved oxygen (DO) and an Atomic Absorption Spectrometer to quantify the heavy metals’ levels, specifically Ni, Zn, Fe, Pb, Cu, and Cr, following the requirements set by the World Health Organization (WHO), Food and Agriculture Organization (FAO), and Department of Energy (DoE) in Bangladesh. The study was carried out on various pollution indices i.e., Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), and Degree of Contamination (C_d). The pH of the samples varied from 6.27 to 8.86. Furthermore, the samples’ TDS and EC ranged from 36 mg/l to 392.56 mg/l and 102.78 μS/cm to 611.51 μS/cm, respectively. The HPI values exhibited substantial variation, with the highest HPI-a (WHO) measuring 52215.6, indicating a severe level of heavy metal contamination. Similarly, the HEI-a (WHO) reached a maximum value of 1252.45, while the highest contamination degree (C_d-a, WHO) was 1248.45 and these results are beyond the acceptable limits for human consumption and ecological balance. Immediate actions are required to develop treatment technologies and management strategies to prevent the potential health risks associated with using untreated mine wastewater.