Isotope Effects as New Proxies for Organic Pollutant Transformation
Thomas B. Hofstetter,
Jakov Bolotin,
Sarah G. Pati,
Marita Skarpeli-Liati,
Stephanie Spahr,
Reto S. Wijker
Affiliations
Thomas B. Hofstetter
Eawag, Swiss Federal Institute of Aquatic Science & Technology Department of Environmental Chemistry Überlandstr. 133 CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland. [email protected]
Jakov Bolotin
Eawag, Swiss Federal Institute of Aquatic Science & Technology Department of Environmental Chemistry Überlandstr. 133 CH-8600 Dübendorf, Switzerland
Sarah G. Pati
Eawag, Swiss Federal Institute of Aquatic Science & Technology Department of Environmental Chemistry Überlandstr. 133 CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland
Marita Skarpeli-Liati
Eawag, Swiss Federal Institute of Aquatic Science & Technology Department of Environmental Chemistry Überlandstr. 133 CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland
Stephanie Spahr
Eawag, Swiss Federal Institute of Aquatic Science & Technology Department of Environmental Chemistry Überlandstr. 133 CH-8600 Dübendorf, Switzerland; Institute of Environmental Engineering, EPF Lausanne, Switzerland
Reto S. Wijker
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland
Assessing the pathways and rates of organic pollutant transformation in the environment is a major challenge due to co-occurring transport and degradation processes. Measuring changes of stable isotope ratios (e.g. 13C/12C, 2H/1H, 15N/14N) in individual organic compounds by compound-specific isotope analysis (CSIA) makes it possible to identify degradation pathways without the explicit need to quantify pollutant concentration dynamics. The so-called isotope fractionation observed in an organic pollutant is related to isotope effects of (bio)chemical reactions and enables one to characterize pollutant degradation even if multiple processes take place simultaneously. Here, we illustrate some principles of CSIA using benzotriazole, a frequently observed aquatic micropollutant, as example. We show subsequently how the combined C and N isotope fractionation analysis of nitroaromatic compounds reveals kinetics and mechanisms of reductive and oxidative reactions as well as their (bio)degradation pathways in the environment.
