Wildfires and Hg remobilization

Mercury distribution in topsoils and vegetation samples and temperature-dependent Hg mobilization simulating wildfires have been investigated near a Cu smelter in semi-arid Namibia. The thermo-desorption experiments performed on the representative Hg-rich topsoils indicated that >91% of the Hg was released at ~340°C, which corresponds to the predominant grassland-fire conditions. Despite the installation of a sulfuric acid plant in the smelter in 2015 and a calculated drop in the estimated Hg emissions (from 1301 ± 457 kg/y for the period 2004-2015 to 67 ± 5 kg/y after 2015), the Hg legacy pool in the smelter surroundings will contribute to wildfire-driven Hg emissions until its complete burn-out. Using the Hg spatial distribution data in the area (184 km2), the estimates indicate that up to 303 kg and 1.3 kg can be remobilized from the topsoils and vegetation, respectively.

Tuhý M., Rohovec J., Matoušková Š., Mihaljevič M., Kříbek B., Vaněk A., Mapani B., Göttlicher J., Steininger R., Majzan J., Ettler V. (2020): The potential wildfire effects on mercury remobilization from topsoils and biomass in a smelter-polluted semi-arid area. Chemosphere 247, 125972. (DOI)

Lecture by Karen Hudson-Edwards

Karen Hudson-Edwards, Professor in Sustainable Mining at University of Exeter (UK), will give a lecture entitled „Environmental Minerals: Bacteria, Worms, Dusts, Toxins and the Human Body“ on Monday 13th January 2020 at 3 pm in Ložiskové sbírky (room no. 120, Albertov 6 building, Faculty of Science, Charles University). The lecture takes part of the European Association of Geochemistry Lecture Tour and is partly supported by Center for Geosphere Dynamics. You are cordially invited!

Second paper of arsenic sulfidation under the low-temperature conditions in the Geochimica et Cosmochimica Acta

This study investigated As-enriched wetland at the Smolotely-Líšnice Au district (Centra Bohemia) using the combination of geochemical (soil and pore water analyses, S isotopes), mineralogical (microprobe, Raman spectrometry) and biological (DNA extraction) method. In this paper, Magda and her co-authors identified a complex assemblage of As and Fe sulfides (realgar, bonazziite, pyrite, greigite) on the fragments of natural organic matter, which play an active role (very fast microbial sulfate reduction vs. slow transfer of solutes) in arsenic immobilization in polluted wetland systems.

Knappová M., Drahota P., Falteisek L., Culka A., Penížek V., Trubač J., Mihaljevič M., Matoušek T. (2019): Microbial sulfidogenesis of arsenic in naturally contaminated wetland soil. Geochimica et Cosmochimica Acta 267, 33-50. https://doi.org/10.1016/j.gca.2019.09.021

Metal mobility in contaminated semi-arid soils

We combined elemental and isotopic studies, leaching techniques and speciation modeling to describe Cu and Pb behavior in contaminated soil profiles of Kombat, Namibia. Tailings, soils and bedrock samples were analyzed. We described pollutants’ behavior in detail for different type of soils and concluded that migration is highly dependent on soil characteristics and element speciation shown by variations, or lack thereof, in concentrations, δ65Cu and 206Pb/207Pb values with depth.

Mihaljevič M., Baieta R., Ettler V., Vaněk A., Kříbek B., Penížek V., Drahota P., Trubač J., Sracek O., Chrastný V., Mapani B. S. (2019): Tracing the metal dynamics in semi-arid soils near mine tailings using stable Cu and Pb isotopes. Chemical Geology 515, 61-76. (DOI)

Dust from mining areas of Namibia

We used a multi-method approach for characterization of dust from mines and smelters in the northern Namibia. In vitro bioaccessibility testing in simulated gastric fluid (SGF) indicated that As, Pb (and also Cd to a lesser extent) exceeded tolerable daily intake limits for these contaminants in the case of slags and smelter dusts, but the exposure risk for local population is only important at the unfenced disposal sites.

The paper published in Environment International is open-accessEttler V., Cihlová M., Jarošíková A., Mihaljevič M., Drahota P., Kříbek B., Vaněk A., Penížek V., Sracek O., Klementová M., Engel Z., Kamona F., Mapani B. (2019): Oral bioaccessibility of metal(loid)s in dust materials from mining areas of Namibia. Environment International 124, 205-215. (DOI)

Thermodynamic properties of arsenates

A complete set of new thermodynamic data has been determined for three Al and Fe arsenate minerals: mansfieldite, angelellite and kamarizaite.

Majzlan J., Nielsen U.G., Dachs E., Benisek A., Drahota P., Kolitsch U., Herrmann J., Bolanz R., Števko M. (2018): Thermodynamic properties of mansfieldite (AlAsO4·2H2O), angelellite (Fe2(AsO4)2O3) and kamarizaite (Fe3(AsO4)2(OH)3·3H2O). Mineralogical Magazine 82, 1333-1354. (DOI)