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)
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!
We attended Goldschmidt 2019 conference in Barcelona, Spain. It was a week full of exciting geochemistry!
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.
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 re-measurement of mercury (Hg) concentrations in archived environmental samples (soils, peats) after several years of storage indicated that there is no statistical difference between new measurements and original data. As a result, archived samples can be used to evaluate historical soil mercury contamination.
As a part of a special issue of the university journal Forum dedicated to 670th anniversary of Charles University foundation, Jakub Trubač, EGG-member and head of Stable and Radiogenic Isotope Laboratory, was interviewed as a representative of Faculty of Science. He starts with the citation of one of his teachers, Dr. Fratišek V. Holub, who said: “Rocks are the only solid basis of our world”:-) Enjoy the interview on pages 52-53 of the electronic document (
A combination of multiple techniques including XAS and isotopes helped to decipher the mobility of Tl in mining-polluted desert soil in Namibia. Mechanical transport of fine particles of post-flotation tailings is probably responsible for Tl dispersion in soil profiles.
A first long-term (2 years) field experiment indicated how As and other metal(loid) contaminants can be released from As-rich copper smelter flue dust after deposition in contrasting soils. Up to 72% of As was leached out from the flue dust after incubation. The majority of As became highly mobile and could represent a risk for individual environmental compartments (soil, water).