Investigating Landfill Leachate Influence on Soil Microbial Biodiversity and Its Cytotoxicity

Abstract

The most important problem related to the collection of waste in landfills is the presence of harmful substances contained in leachate resulting from the flow of atmospheric precipitation through the deposited waste, which may end up in the soil. As a result, the soil’s chemical degradation occurs, which may result in a change in the structure and activity of microorganisms. In addition, leachate can end up in groundwater that may be hazardous to human health. The aim of the study was to determine the effect of landfill leachate on selected physicochemical, biological and biochemical properties of soils. The cytotoxicity of soil filtrates (SF) in human cell lines and their effect on apoptosis were also analyzed. In the pot experiment, leachate was added to the soil in two doses: 50LL (50% of the N dose) and 100LL (100% of the N dose). Selected physicochemical properties, activity of enzymes, diversity of bacteria and fungi by the T-RFLP approach were determined in soil samples. As a result of the analyses, it was found that LL causes an increase in the activity of dehydrogenases and a decrease in β-glucosidase. In the soils treated with LL, bacterial T-RF (144) bp, (179) bp and (413) bp were specific, while fungal were T-RF (390) bp, (441) bp and (595) bp. Potentially cytotoxic effects of SF and reduction in apoptosis in neoplastic cells were found in in vitro tests. LL and SF are complex matrices with a variable composition, which means that their impact on the soil environment must be constantly monitored.