Raum: Geo III, Raum 211
I am interested in improving our understanding of biogeochemical processes that control the fate, bioavailability and mobilization of trace elements in soils and sediments. Much of my work has focused on the mobility of toxic metal(loids) in contaminated soils, in particular with regard to changes in redox conditions as induced by flooding or waterlogging. In my current project, I explore how sulfide generation and iron(II)-catalyzed mineral (trans)formations – two key processes in wetland soils – impact speciation and mobility of toxic antimony and arsenic. This reseach is important for reliable risk assessments of poorly-drained contaminated sites and the design of appropriate management strategies.
In a second project, I use geochemical methods such as extractions, SEM-EDX and synchrotron-based speciation analysis, to explore the risk of antimony leaching from synthetic baby clothes into the human body. Antimony trioxide, which was classified as a possible human carcinogen, is used as a catalyst during the manufacture of polyester fibres. Remnant antimony present in synthetic clothing fibers may enter the human body via various exposure routes, for example during sucking or by dermal absorption, and thus pose a risk to babies.
I am always interested in exchanging scientific insights and building new collaborations, particularly when it is related to my favorite element antimony.
EDUCATION AND POSTDOCTORAL TRAINING
Since 11/2017: Research Fellow (including maternity leave for my second son)
"Outstanding Female Scholars for the University of Bayreuth". Grant program by the Female Professor Programme of Germany's Federal Ministry of Education and Research.
Environmental Geochemistry Group (Prof. Britta Planer-Friedrich), University of Bayreuth, Germany
2015 – 2017: Postdoctoral Researcher
Southern Cross GeoScience (Prof. Edward Burton), Southern Cross University, Australia
2009 – 2015: Research Associate and PhD studies - Dr. sc. ETH Zurich (including maternity leave for my first son)
Institute of Terrestrial Ecosystems, ETH Zurich, Switzerland.
Thesis title: "Antimony leaching from contaminated soil under changing redox conditions".
2002 – 2008: MSc and BSc studies (Diplom) of Geoecology
Technische Universität Braunschweig Germany
MSc thesis project at the Swedish University of Agriculture, Uppsala: "Effects of non-equilibrium and non-ideal transport and transformation processes on pesticide leaching in a structured clay soil at Brimstone Farm (UK)"
BSc student research project project (5 months) at the German Development Service in Dumaguete, Philippines: "Assessment of a dumpsite in Dumaguete/Philippines with emphasis on groundwater quality"
- ISTEB Early Career Researcher Award: 1,300 € travel grant for the ICOBTE Zurich (2017)
- ETH Medal Award for outstanding Doctoral Thesis (2015).
- Environmental Chemistry student award for the best oral presentation (12th International Conference on Biogeochemistry of Trace Elements in the Environment ICOBTE, Athens, Georgia, USA, 2013).
- Environmental Chemistry student award for the best oral presentation (2nd International Workshop on Antimony in the Environment, Jena, Germany, 2011).
- Diplom (M.Sc.) faculty award (2008) for excellence in studies of Geoecology.
- Scholarship from the German National Academic Foundation (Studienstiftung des Deutschen Volkes) for studies of Geoecology (2005 – 2008).
- Vordiplom (B.Sc.) university award (2005) for excellent studies.
GRANTS AND SCHOLARSHIPS
15,573 €. Mobility grant from the Germany Academic Exchange Service (DAAD-PPP Australia): "Exploring antimony speciation and mobility in sulfidic soils and sediments." 2019-2020. (Lead investigator)
48 hrs. Australian Synchrotron Research Program (AS181/XAS/13073) "Resolving the impact of microbial iron(III) reduction on subsurface antimony mobility: 2. Iron K-edge XAS" 2017. (Lead investigator: Edward D. Burton)
72 hrs. Australian Synchrotron Research Program (AS181/XAS/13045) "Resolving the impact of microbial iron(III) reduction on subsurface antimony mobility: 1. Antimony K-edge XAS " 2017. (Lead investigator: Edward D. Burton)
62,400 €. "Outstanding Female Scholars for the University of Bayreuth". Grant program by the Female Professor Programme of Germany's Federal Ministry of Education and Research. 2017-2019. (Lead investigator)
3,300 €. Australian Synchrotron Access Program (AS/IA172/12797). “An XAS investigation of sulfur speciation during during abiotic sulfidization of antimony-rich ferrihydrite ” 2017. (Lead investigator)
48 hrs. Australian Synchrotron Research Program (AS173/XAS/12507) "Antimony speciation during the iron(II)-induced transformation of antimony(V)-bearing ferrihydrite." 2017. (Lead investigator: Edward D. Burton)
7,500 €. Southern Cross Research Seed Grant. "Unraveling the role of nanoparticulate iron minerals as sinks for antimony in the environment." 2017. (Lead investigator: Edward D. Burton)
72 hrs. National Synchrotron Radiation Research Centre (Taiwan). 2017-2-104-1: "An XAS K-edge investigation of iron and sulfur speciation during abiotic sulfidization of antimony-rich ferrihydrite." 2017. (Lead investigator)
72 hrs. Australian Synchrotron Research Program (AS171/XAS/11609) "Resolving electron transfer to As(V)-schwertmannite due to fires in seasonal wetlands" 2017. (Lead investigator: Scott G. Johnston)
120 hrs. Australian Synchrotron Research Program (AS171/XAS/11638) "An XAS investigation into the speciation of antimony during abiotic sulfidization of antimony-rich ferrihydrite" 2017. (Lead investigator)
48 hrs. Australian Synchrotron Research Program (AS162/XAS/10710) "Resolving the effect of seawater inundation and sulfate reduction on antimony mobility in a contaminated wetland" 2016. (Lead investigator: William W. Bennett)
72 hrs. Australian Synchrotron Research Program (AS162/XAS/10765) "Antimony mobility in sulfidic environments: an XAS study of antimony sorption to mackinawite (FeS) " 2016. (Lead investigator)
8,600 €. Southern Cross Research Seed Grant. Mineralogical controls on the mobility of Antimony in a tailings contaminated coastal wetland. 2015. (Lead investigator: Scott G. Johnston)
7,500 €. Southern Cross Research Seed Grant. New perspectives on antimony mobility in subsurface environments: resolving unexplored interactions with the sulfur cycle. 2015. (Lead investigator: Edward D. Burton)
95,500 € SNSF Early Postdoc.Mobility Fellowship (Grant P2EZP2_159106). „Exploring the coupling of antimony mobility to sulphur transformations in anoxic environments“. 2015-2017. (Lead investigator)
8,200 € armasuisse Immobilien, Eidgenössisches Departement für Verteidigung, Bevölkerungsschutz und Sport „Exploring seasonal effects in antimony and toxic metal leaching from acidic and calcareous shooting range soil“ 2014-2015. (Lead investigator)
31,700 €. armasuisse Immobilien, Eidgenössisches Departement für Verteidigung, Bevölkerungsschutz und Sport „Antimony and toxic metal leaching from shooting range soils under different soil management“ 2011-2013. (Lead investigator)
203,500 €. Swiss National Science Foundation (Grant 200021-13025). "Antimony leaching from contaminated soil under different water regimes" 2010-2013. (Project development and proposal writing; Lead applicant: R. Schulin)
18. Hockmann, K., Planer-Friedrich, B., Johnston, S.G., Burton, E.D., Release and immobilisation of antimony during sulfidisation of ferrihydrite. In preparation for publication in Geochimica et Cosmochimica Acta.
17. Karimian, N., Burton, E.D., Johnston, S.G., Hockmann, K., Chopalla, G. Antimony speciation and partitioning in iron- and humic acid-rich environments: Implications for antimony mobility. Submitted to Science of the Total Environment.
16. Burton, E.D., Chopalla, G., Vithana, C.L., Karimian, N., Hockmann, K., Johnston, S.G. Chromium(VI) formation via heating of Cr(III)-Fe(III)-(oxy)hydroxides: A pathway for fire-induced soil pollution. 2019. Chemosphere 222: 440-444.
15. Burton, E.D., Hockmann, K., Johnston, S.G., Karimian, N. Antimony mobility in reducing environments. 2019. The effect of microbial iron(III)-reduction and associated secondary mineralization. Geochimica et Cosmochimica Acta 245: 278-289.
14. Arsic, M., Teasdale, P.R., Welsh, D.T., Johnston, S.G., Burton, E.D., Hockmann, K., Bennett, W.W. 2018. Diffusive gradients in thin films (DGT) methods reveal antimony and arsenic mobility differs in a contaminated wetland sediment during an oxic-anoxic transition. Environmental Science and Technology 52: 1118–1127.
13. Tandy, S., Hockmann, K., Keller, M., Studer, B., Papritz, A., Schulin, R., 2018. Antimony mobility during prolonged waterlogging and reoxidation of shooting range soil: a field experiment. Science of the Total Environment 624: 838-844
12. Hockmann, K., Tandy, S., Studer, B., Evangelou, M.W.H., Schulin, R., 2018. Plant uptake and availability of antimony, lead, copper and zinc in oxic and reduced shooting range soil. Environmental Pollution: 238, 255-262.
11. Johnston, S.G., Bennet, W.W., E.D. Burton, Hockmann, K., Dawson, N., Karimian, N., 2018 Rapid arsenic (V)-reduction by fire in schwertmannite-rich soil enhances arsenic mobilisation. Geochimica et Cosmochimica Acta 227:1-18.
10. Bennett, W.W., Hockmann, K., Johnston, S.G., Burton, E.D., 2017. Synchrotron X-ray absorption spectroscopy reveals antimony sequestration by reduced sulfur in a freshwater wetland sediment. Environmental Chemistry 14:345-349.
9. Rajpert, L., Kolvenbach, B.A., Ammann, E.M., Hockmann, K., Nachtegaal,M., Eiche, E., Schaeffer, A., Corvini, p. F.-X., Sklodowska,A., and M. Lenz. 2016. Arsenic mobilization from historically contaminated mining soils in a continuously operated bioreactor: Implications for risk assessment. Environmental Science and Technology 50: 9124–9132
8. Hockmann, K., Lenz, M., Tandy, S., Schulin, R., 2015. Antimony retention and release from drained and waterlogged shooting range soil under field conditions. Chemosphere 134: 536–543.
7. Cui, X.-D., Wang, Y.-J., Hockmann, K., Zhou, D.-M., 2015. Effect of iron plaque on antimony uptake by rice (Oryza sativa L.). Environmental Pollution 204: 133-140.
6. Hockmann, K., Tandy, S., Lenz, M., Schulin, R., 2014. Leaching of antimony from contaminated soil under manganese- and iron-reducing conditions: column experiments. Environmental Chemistry 11: 624–631.
5. Hockmann, K., Lenz, M., Tandy, S., Nachtegaal, M., Janousch, M., Schulin, R., 2014. Release of antimony from contaminated soil induced by redox changes. Journal of Hazardous Materials 275: 215–221.
4. Wan, X.-m., Tandy, S., Hockmann, K., Schulin, R., 2013. Changes in Sb speciation with waterlogging of shooting range soils and impacts on plant uptake. Environmental Pollution 172: 53-60.
3. Wan, X.-m., Tandy, S., Hockmann, K., Schulin, R., 2013. Effects of waterlogging on the solubility and redox state of Sb in a shooting range soil and its uptake by grasses: a tank experiment. Plant and Soil 371: 155-166.
2. Evangelou, M.W.H., Hockmann, K., Pokharel, R., Jakob, A., Schulin, R., 2012. Accumulation of Sb, Pb, Cu, Zn and Cd by various plants species on two different relocated military shooting range soils. Journal of Environmental Management 108: 102-107.
1. Conesa, H.M., Wieser, M., Gasser, M., Hockmann, K., Evangelou, M.W.H.,Studer, B., Schulin, R. 2010. Effects of three amendments on extractability and fractionation of Pb, Cu, Ni and Sb in two shooting range soils. Journal of Hazardous Materials 181: 845-850.
1. Hockmann, K. and Schulin, R., 2013. Leaching of antimony from contaminated soils. In: Selim, H.M. (Ed.), Competitive sorption and transport of heavy metals in soils. Boca Raton. CRC Press. Taylor & Francis Group, pp. 119-145.
>> Persönliche Homepage
>> Betreute Abschlussarbeiten