Properties of mine soil and its affects on bioaccumulation of metals in tree species: case study from a large opencast coalmining project

Abstract

Opencast mining results in severe destruction of the landscape due to the formation of overburden dumps and voids at mining sites, increased erosion, altered aesthetics and an increased pollution load onto the surroundings. Reclamation of these mine dumps forms an integral part of environmental management plan for any mining project. An advance understanding of the properties of mine soil (e.g. rock geochemistry, rock depth profiling) is important in the preparation of reclamation and closure plans. The studies undertaken in the Central Coalfield Limited (CCL) KD Heslong opencast project, revealed that the bioavailability of toxic metals depends on the physico-chemical characteristics of mine soil, and that bioaccumulation of toxic metals varies among tree species. In the nutritionally poor mine soil, the plant species Dalbergia sissoo, Cassia seamea, Acacia mangium and Acacia auriculiformis were found growing satisfactorily. Addition of topsoil and liming in the plantation pits was found to be essential and, if possible, incorporation of acid neutralizing materials such as fly ash should be undertaken.

Keywords:

• Mine soil
• Reclamation
• Heavy metals
• Bioaccumulation
• Tree species

Acknowledgements

This research was funded by the Ministry of Environment and Forest, Government of India (J-15012/38/98-IA II (M). The author also thanks the KD Heslong authority and Environmental Officer, Mr Ranjan Samanta, for providing necessary help during the field study. Thanks also go to Prof. Joan Osborne (Department of Environmental Biology (Mine Rehabilitation Group), Curtin University of Technology, Perth, Australia) for meticulously correcting the English of the manuscript, updating statistical analysis of the data and thorough checking of plant names.