Comparison of Microbial and Geochemical Conditions of Lignite Coal Spoil and Overburden Areas and their Environmental Impact

Abstract

During the 20th century, Germany belonged to the world’s largest producers of lignite coal. Approaches for remediation of lignite spoil and overburden material were carried out since at least the last 50 years. Today, results of former remediation can be evaluated by their long-term effects. Coal spoil seepage waters can impact billions of m3 of ground water in involved areas for a very long time horizon (eternity impacts). In the last years our working group had studied especially lignite coal spoil sites in the Lusatia (East Germany) with sandy substrates and faster vertical mass transport processes. In new investigations, another coal spoil site in Middle Germany with more cohesive soil substrates and layers of drift clays was studied, and geochemical and microbial parameters were characterized. The investigated site partially had a remediated topsoil layer since 40 years, and since this time agricultural cultivation of different plants (grains, legumes, Pocaceae) was performed. In this paper, data of different microbial populations in the coal spoil substrate and geochemical background data are given, and they are compared with former data of microbial communities in sandy substrates and their impact to the environment. Finally, the success of long-term remediation of such sites, the influence onto microbial life and impact to the environments will be compared and discussed.