Solid-phase distribution and mobilization of iron and manganese from sulfidic mine waste under neutral drainage conditions at Rudabánya mine, Hungary
Year: 2025
Type: article
Abstract: An examination was conducted to explore the connection between the mine waste deposited near Rudabánya town (Hungary) and the contamination of local stream with Fe and Mn. The investigation involved integrating mineralogical methods (XRD, SEM-EDS) with geochemical approaches (sequential extraction and modeling) mainly to evaluate the dominant forms of metals in the waste and their potential mobilization during weathering processes. The waste is primarily consisted of calcite, dolomite, siderite, with minor quartz, illite, goethite, maghemite, barite, and pyrite. Geochemical model calculations predicted the consistent dissolution of siderite, calcite, pyrite, and illite during the interaction between local rainwater and waste material, as well as the precipitation of gypsum and poorly crystalline Fe-Mn-Al (oxyhydr)oxides over the next 50 years. The dissolution of pyrite leads to the release of associated toxic metals (such as Fe, Co, Cd, As, and Hg) into the pore space. The acidity induced carbonate dissolution facilitates the mobilization of Mn and additional Fe. Sequential extraction results indicated that a significant portion of Fe (75%), Mn (75%), Cr (32%), Co (33%), Ni (38%), Cu (19%), Zn (55%), As (36%), Cd (41%), Pb (66%) were associated with the (oxyhydr)oxide, exchangeable, and water-soluble fractions, which are generally considered as environmentally available. Despite their high concentrations in the waste, these metals are effectively retained via sorption mechanisms to secondary precipitates at the elevated pH and oxidative conditions of the waste. In contrast, some fractions of Fe2+ and Mn2+ enter the local stream, exceeding multiple regulatory threshold values in their concentrations. This study highlights the role of mineralogy, element distributions, and environmental factors in both the mobilization and attenuation of metal contaminants in a seemingly non-acidic mine waste site. Our findings underscore the importance of implementing preventative measures for carbonate rich waste deposits to ensure sustainable waste and water management strategies.
Source: Journal of Hazardous Materials
Institution: Eötvös Loránd University
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,340
OpenAlex ID: W4407260773