The Influence of Road Maintenance Substances on the Growth of Graminaceous Plants

Abstract

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and elevation of the introduced bacterial strains throughout the experiment. Reference to this paper should be made as follows: Nõ lvak, H.; Truu, J.; Limane, B.; Truu, M.; Cepurnieks, G.; Bartkevičs, V.; Juhanson, J.; Muter, O. 2013. Microbial community changes in TNT spiked soil bioremediation trial using biostimulation, phytoremediation and bioaugmentation, Journal of Environmental Engineering and Landscape Management 21(3): 153Á162. http://dx.abstract. The article describes the experimental research on the effect of road maintenance materials on three species of graminaceous plants. The experiment was carried out using technical granular sodium chloride (NaCl) treated with potassium hexacyanoferrate -a road maintenance material most widely applied in wintertime in Lithuania. As an alternative, an organic material obtained on the basis of molasses, patented under the name of Safecote in Europe, was selected for the experiment. Three species of graminaceous plants, most frequently used for roadside planting in Lithuania when building new and reconstructing or renovating the existing motor roads, were analysed: perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), and common meadow-grass (Poa pratensis L.). The paper presents experimental findings regarding the effect of road maintenance materials on the parameters of graminaceous plants -the height of the above-ground part and phytomass.