Staff

Thomas Hofstetter

PD Dr. Thomas Hofstetter

Senior Scientist, Group Leader

Department Environmental Chemistry

About Me

Thomas B. Hofstetter is a senior scientist at Eawag's Department of Environmental Chemistry and leads the Environmental Chemistry Stable Isotope Lab. His primary interest is to understand how degradation and formation reactions organic pollutants work.


Even in Environmental Chemistry "little things can make a big difference". Our preferred level of study is therefore the molecular scale. The know-how obtained from talking to molecules, atoms, and a few sub-atomic particles enables us assess quantitatively the numerous processes that ultimately determine the fate of organic pollutants behave in aquatic environments. Thomas Hofstetter and his research group apply a variety of approaches to achieve their research goals.

  1. We study of reaction mechanisms in (laboratory) model systems for enzyme- and mineral-catalyzed redox reactions, water disinfection processes, and photochemical transformations.
  2. With compound-specific stable isotope analysis, we have an excellent tool at hand for studying (bio)chemical reactions. Tiny variations of isotope ratios found at natural isotopic abundances reveal, on the one hand, the origin of an element or molecule. On the other hand, the systematic variation of isotope ratios reflect isotope effects of chemical reactions and physical processes and are, therefore powerful proxies for reactive processes on very different time scales.
  3. Finally, we aim at understanding the biogeochemical context, in which reactions of organic and inorganic pollutants happen. To this end, we study the redox properties of iron-bearing minerals, specifically, phyllosilicates and iron oxides from their availability as terminal electron acceptors to the quantification of fundamental redox parameters.
None of these goals would be achieved without the fruitful collaboration with and advice from numerous colleagues and friends of good (environmental and chemical) sciences.

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Projects

N-nitrosamines such as N-nitrosodimethylamine (NDMA) are of public and regulatory concern because these potent carcinogens can be formed as unintented by-products during drinking and waste water disinfection/oxidation.
Nitroaromatic explosives persist in the subsurface in different phases (e.g., bound to soil or sediment matrix or as solid-phase residues) and it is extremely challenging to assess biotic and mineral-catalyzed degradation. With the combined analysis of C, N, and H isotope fractionation, we can quantify transformation, even if it takes place via several potentially competing pathways over time-scales of decades.
A new approach for the CSIA of aquatic micropollutants in the sub-microgram/liter range

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Curriculum Vitae

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Publications

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Melsbach, A.; Torrentó, C.; Ponsin, V.; Bolotin, J.; Lachat, L.; Prasuhn, V.; Hofstetter, T. B.; Hunkeler, D.; Elsner, M. (2020) Dual-element isotope analysis of desphenylchloridazon to investigate its environmental fate in a systematic field study: a long-term lysimeter experiment, Environmental Science and Technology, 54(7), 3929-3939, doi:10.1021/acs.est.9b04606, Institutional Repository
Chen, G.; Hofstetter, T. B.; Gorski, C. A. (2020) Role of carbonate in thermodynamic relationships describing pollutant reduction kinetics by iron oxide-bound Fe2, Environmental Science and Technology, 54(16), 10109-10117, doi:10.1021/acs.est.0c02959, Institutional Repository
Bopp, C. E.; Kohler, H. P. E.; Hofstetter, T. B. (2020) Enzyme kinetics of organic contaminant oxygenations, Chimia, 74(3), 108-114, doi:10.2533/chimia.2020.108, Institutional Repository
Berens, M. J.; Hofstetter, T. B.; Bolotin, J.; Arnold, W. A. (2020) Assessment of 2,4-dinitroanisole transformation using compound-specific isotope analysis after in situ chemical reduction of iron oxides, Environmental Science and Technology, 54(9), 5520-5531, doi:10.1021/acs.est.9b07616, Institutional Repository
Aeppli, M.; Vranic, S.; Kaegi, R.; Kretzschmar, R.; Brown, A. R.; Voegelin, A.; Hofstetter, T. B.; Sander, M. (2019) Decreases in iron oxide reducibility during microbial reductive dissolution and transformation of ferrihydrite, Environmental Science and Technology, 53(15), 8736-8746, doi:10.1021/acs.est.9b01299, Institutional Repository
Sander, M.; Hofstetter, T. B.; Gorski, C. A. (2015) Electrochemical analyses of redox-active iron minerals: A review of nonmediated and mediated approaches, Environmental Science and Technology, 49(10), 5862-5878, doi:10.1021/acs.est.5b00006, Institutional Repository
Schwarzenbach, R. P.; Egli, T.; Hofstetter, T. B.; von Gunten, U.; Wehrli, B. (2010) Global water pollution and human health, Annual Review of Environment and Resources, 35, 109-136, doi:10.1146/annurev-environ-100809-125342, Institutional Repository
Elsner, M.; Jochmann, M. A.; Hofstetter, T. B.; Hunkeler, D.; Bernstein, A.; Schmidt, T. C.; Schimmelmann, A. (2012) Current challenges in compound-specific stable isotope analysis of environmental organic contaminants, Analytical and Bioanalytical Chemistry, 403(9), 2471-2491, doi:10.1007/s00216-011-5683-y, Institutional Repository

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Address

E-Mail: thomas.hofstetter@eawag.ch
Phone: +41 58 765 5076
Fax: +41 58 765 5802
Address: Eawag
Überlandstrasse 133
8600 Dübendorf
Office: BU E13

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Expert of

isotopes, micropollutants

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