Combined Approach Using Soil and Fly Ash Analysis to Understand the Environmental Consequences of Coal Combustion in Thermal Power Stations in the City

Energy production may lead to soil contamination. This study uses a combined approach to understand the environmental effect of fly ashes resulting from the activity of two thermal power stations (Siekierki and Żerań TPSs). Therefore, the metal(loid)s content and mobility of these elements in soils were evaluated. Furthermore, the effect of root exudates on two types of fly ashes (KKSL-fly ash from conventional coal combustion and KFZL-fly ash from fluidal coal combustion) was studied based on experiments of fly ashes with Artificial Root Exudates (AREs). The study shows that the studied soils are not contaminated according to Polish law. For example, the Cd, Cu, Pb, and Zn content in soils around the Siekierki TPS was up to 0.53, 30.3, 58.8, 138 mg kg^-1, respectively. The Cd, Cu, Pb, and Zn content in soils around the Żerań TPS was up to 1.24, 28.4, 131, and 374 mg kg^-1, respectively. Among investigated elements, the Cu, Cd, and Mn revealed the highest mobility in studied soils (up to 87.4% of Cu in soils around the Żerań TPS), which is controlled by many factors, i.e., Fe,Mn,Al-oxides and pH. The experiment simulating fly ashes weathering demonstrated that ashes are more prone to dissolution when exposed to root exudates relative to H₂O of the corresponding pH. The significant finding is that the KKSL is more susceptible to dissolution with AREs compared to the KFZL, probably due to the glass dissolution in the former one. Therefore, this study may contribute to developing remediation strategies for ash dumps.