Articles | Volume 6, issue 3
Research article
08 Jul 2015
Research article |  | 08 Jul 2015

Assessment of environmental soil quality around Sonepur Bazari mine of Raniganj coalfield, India

R. E. Masto, S. Sheik, G. Nehru, V. A. Selvi, J. George, and L. C. Ram

Abstract. Assessment of soil quality is one of the key parameters for evaluation of environmental contamination in the mining ecosystem. To investigate the effect of coal mining on soil quality, opencast and underground mining sites were selected in the Raniganj coalfield area, India. The physical, chemical, and biological parameters of the soils, and trace metals and PAHs (polycyclic aromatic hydrocarbons) in the soils were evaluated. Soil dehydrogenase (+79 %) and fluorescein (+32 %) activities were significantly higher in underground mine (UGM) soil, whereas peroxidase activity (+57 %) was higher in opencast mine (OCM) soil. Content of As, Be, Co, Cr, Cu, Mn, Ni, and Pb was significantly higher in OCM soil, whereas Cd was higher in UGM. In general, the PAHs contents were higher in UGM soils, probably due to the natural coal burning at these sites. The observed values for the above properties were converted into a unitless score (0–1.00) and the scores were integrated into an environmental soil quality index (ESQI). In the unscreened index (ESQI-1) all the soil parameters were included and the results showed that the quality of the soil was better for UGM (0.539) than the OCM (0.511) soils. Principal component analysis was employed to derive ESQI-2 and accordingly, total PAHs, loss on ignition, bulk density, Be, Co, Cr, Ni, Pb, and microbial quotient (respiration: microbial biomass ratio) were found to be the most critical properties. The ESQI-2 was also higher for soils near UGM (+10.1 %). The observed indicators and the ESQI results revealed that soil quality assessment for these coal mining soils is largely depended on soil PAHs and potentially toxic trace metals. The proposed ESQI may be further refined by incorporating specific parameters related to human exposure risks and exposure pathways.

Short summary
Impact of coal mining on soil was assessed through an integrated environmental soil quality index (ESQI). Biological activity was higher in underground mine (UGM) soil. As, Be, Co, Cr, Cu, Mn, Ni, and Pb were higher in opencast mine (OCM) soil, whereas Cd was higher in UGM. Polycyclic aromatic hydrocarbons (PAHs) were higher in UGM soil. Calculated ESQI, based on total PAHs, loss on ignition, bulk density, Be, Co, Cr, Ni, Pb, and microbial quotient, was higher for UGM (+10.1%) than OCM soils.