Copper isotopes help to decipher processes during Cu-ore heap leaching

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For the first time, copper isotopes (expressed as δ65Cu) wer used as indicators of reactions occurring during the Cu-ore heap leaching, an in situ technological process used for extraction of this strategic metal. In comparison with unleached ore (average δ65Cu  -1.47‰), leached ores exhibit lighter isotopic values (average δ65Cu -6.01‰) and enrichment of the leachate in heavier 65Cu isotope indicating a dissolution of primary Cu-bearing minerals along with an oxidation process. Our results, based on combined measurements of Cu isotopes and mineralogical investigation with geochemical modelling, can be used as analogy of Cu leaching in gossans. 

Sracek O., Ettler V., Mihaljevič M., Kříbek B., Mapani B., Penížek V., Zádorová T., Vaněk A. (2024): Identification of processes in Cu-ore heap leaching using Cu isotopes and leachate chemistry at Tschudi mine, northern Namibia. Hydrometallurgy 228, 106356. (DOI)

Congratulations Petra!

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On Thursday June 13, 2024, Petra Stubbe successfully defended her PhD thesis entitled “Effects of phosphate on the mobility of arsenic in contaminated areas”. Congratulations, Petra!

Petra with reviewers of the doctoral thesis, prof. Alexandra Courtin-Nomade (Université Paris-Saclay), prof. Edgar Hiller (Univerzita komenského v Bratislave), and her supervisor, Petr Drahota.

The Environmental Geochemistry Group is part of the OP JAK project „Geohazards“

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EGG is actively involved in the objective of the OP JAK project (Natural and anthropogenic georisks; project number: CZ.02.01.01/00/22_008/0004605). Within Work Package 5 (Geochemical risks and contaminations), our researchers will delve into following areas:

  • Examination of pollutant behavior in soils;
  • Analysis of mining and metallurgical wastes, particularly concerning their toxic properties and potentially significant economic elements;
  • Study of substance behaviors during natural fires.

The researchers contributing to this project include: Martin Mihaljevič, Vojtěch Ettler, Petr Drahota, Maria Vaňková, Filip Košek, Adam Culka, Marek Tuhý, Petr Fleissig, and Martin Lichovník. EGG is set to collaborate closely with the Czech University of Life Sciences (Department of Pedology and Soil Protection) and Masaryk University (Recetox). As part of our initiative, the project aims to enhance the infrastructure and laboratories, particularly focusing on ICP MS, XRD, and Raman spectrometry.

Dissolved phosphate decreases the stability of ferric arsenates

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The significant release of arsenic observed from ferric arsenate minerals in the presence of elevated phosphate levels underscores the complexity of their stability in natural environments. Our findings highlight the need to reconsider phosphate treatments in extraction procedures involving ferric arsenates, emphasizing the importance of cautious application in managing polymetallic mine wastes. For sustainable land management, minimizing long-term phosphate additions to arsenic-contaminated soils and mine tailings containing ferric arsenates is crucial to mitigate As(V) export into surface waters and groundwater.

Petra Stubbe (Venhauerova), Irena Matulková, Christian Mikutta, Petr Drahota (2024): Dissolved phosphate decreases the stability of amorphous ferric arsenate and nano-crystalline yukonite. Journal of Hazardous Materials 471, 134374. (DOI)

Welcome to our new PhD students

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Our new PhD students have just joined EGG. Petr Fleissig (left) will work on silver isotopes and Martin Lichovník (right) on speciation, extraction, and potential recovery of valuable metals from wastes. Welcome!

Marek Tuhý joined CSIRO

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Marek Tuhý became a visiting postdoctoral scientist in the National Bushfire Behaviour Research Laboratory, Land & Water Division, CSIRO. Thanks to his postdoctoral fellowship project from the Czech Science Foundation, he will spend 2 years in Canberra, Australia, working on the experiments simulating the effect of wildfires on remobilization and transformations of metal(loid)s.

Alda Vieira successfully completed PhD

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On Tuesday September 19, 2023, Alda M. D. Vieira successfully completed her PhD thesis entitled “Mercury dynamics in soil systems: A comprehensive study on natural and anthropogenic sources using elemental and isotopic analysis”. Congratulations, Alda, and good luck for your future job!
Alda with her supervisor, Dr. Maria Vaňková and referees, Drs. Barbora Doušová and Tomáš Navrátil.

Rafael Baieta completed his PhD

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On December 14, 2022, Rafael Baieta successfully defended his PhD thesis entitled “A study of the behavior of selected metals in affected environments using isotopic approach” completed under supervision of prof. Martin Mihaljevič. On the photo you find Rafael with the external reviewers Dr. Tomáš Navrátil (left) and Dr. Václav Tejnecký (right). Congratulations, Rafael!

Discharged phosphorus releases arsenic from streambed sediments

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Wastewater treatment plants are an important source of phosphorus to the environment. They are estimated to bring between 25 and 45 % of total phosphorus in freshwaters. This study describes how discharged phosphate releases arsenic from streambed sediments into freshwaters. After seven years, the concentration of total As in the streambed sediment below the wastewater treatment plant decreased by 25 % due competitive desorption of arsenate by phosphate.

Petra Venhauerova, Petr Drahota, Ladislav Strnad, Šárka Matoušková (2022): Effects of a point source of phosphorus on the arsenic mobility and transport in a small fluvial system. Environmental Pollution 315, 120477. (DOI)

Helena Jelenová and Magdaléna Peřestá defended their PhD

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On Thursday 22nd September 2022, Helena Jelenová (née Kindlová) and Magdaléna Peřestá (née Knappová) successfully defended their PhD theses entitled “Arsenic speciation in mining wastes – case studies in systems dominated by ferric sulfo-arsenates” and “Speciation of arsenic under reducing conditions of organic-rich soil”, respectively. Both theses were supervised by Dr. Petr Drahota. On the photos you will see both ladies with their supervisor and reviewers Dr. Michal Filippi (Geological Institute of the CAS), Dr. Ľubomír Jurkovič (Comenius University, Bratislava), Prof. Edgar Hiller (Comenius University, Bratislava) and Dr. Barbora Doušová (University of Chemistry and Technology Prague). It was a successful ARSENIC DAY. Congratulations!