EESS talk on "Unravelling the environmental fate of organic micropollutants using stable isotope methods"
Event details
Date | 13.11.2018 |
Hour | 12:15 › 13:15 |
Speaker |
Dr Daniel Hunkeler, Professor of Hydrogeology, Director of CHYN (Centre of Hydrogeology et de Geothermics), University of Neuchâtel, CH He is a professor of the Centre for Hydrogeology and Geothermics (CHYN) of the University of Neuchâtel. He directs the hydrochemistry and contaminants laboratory. His research focusses on the behavior of organic contaminants in the subsurface with an emphasis on new laboratory and computational method to quantify reactive processes. |
Location | |
Category | Conferences - Seminars |
Abstract:
Compound-specific isotope analysis (CSIA) is a powerful method to track the fate of contaminants in the aquatic systems, so far mainly applied to legacy contaminants, such as chlorinated and petroleum hydrocarbons. There is growing interest to apply the method also to polar organic micropollutants, such as pesticides, pharmaceuticals and consumer care products, which are of increasing concern for human and ecosystem health. CSIA of polar organic micropollutants is demanding because they tend to occur at low concentrations, are challenging to extract from water, more difficult to transform to the IRMS measurement gas and are transformed by numerous mechanisms, whose isotope effects are not known yet. In the presentation, the main findings from a collaborative research program to extent CSIA to organic micropollutants are presented.
Thanks to the successful development of large-volume (up to 40L) pre-concentration and clean-up methods, it was possible to perform CSIA at environmentally relevant concentrations (as low as 0.2 µg/L) even if matrix to analyte ratios were highly unfavorable. Using a combination of LC-IRMS, GC-IRMS combined with new derivatization methods, and GC-qMS, multi-element (C, N and Cl) CSIA became feasible for frequently detected pesticides, their metabolites and consumer care products. The methods were field-tested in a three-year lysimeter experiment and at waste water treatment plants. While pesticide/metabolite concentrations strongly fluctuated in the lysimeter study due to the highly transient hydrological conditions, CSIA data show a steady enrichment of heavy isotopes for some compounds, even if injected below the root zone. These results highlight the potential of multi-element CSIA to demonstrate transformation of polar organic micropollutants under transient environmental conditions, which is difficult to achieve with other methods.
Compound-specific isotope analysis (CSIA) is a powerful method to track the fate of contaminants in the aquatic systems, so far mainly applied to legacy contaminants, such as chlorinated and petroleum hydrocarbons. There is growing interest to apply the method also to polar organic micropollutants, such as pesticides, pharmaceuticals and consumer care products, which are of increasing concern for human and ecosystem health. CSIA of polar organic micropollutants is demanding because they tend to occur at low concentrations, are challenging to extract from water, more difficult to transform to the IRMS measurement gas and are transformed by numerous mechanisms, whose isotope effects are not known yet. In the presentation, the main findings from a collaborative research program to extent CSIA to organic micropollutants are presented.
Thanks to the successful development of large-volume (up to 40L) pre-concentration and clean-up methods, it was possible to perform CSIA at environmentally relevant concentrations (as low as 0.2 µg/L) even if matrix to analyte ratios were highly unfavorable. Using a combination of LC-IRMS, GC-IRMS combined with new derivatization methods, and GC-qMS, multi-element (C, N and Cl) CSIA became feasible for frequently detected pesticides, their metabolites and consumer care products. The methods were field-tested in a three-year lysimeter experiment and at waste water treatment plants. While pesticide/metabolite concentrations strongly fluctuated in the lysimeter study due to the highly transient hydrological conditions, CSIA data show a steady enrichment of heavy isotopes for some compounds, even if injected below the root zone. These results highlight the potential of multi-element CSIA to demonstrate transformation of polar organic micropollutants under transient environmental conditions, which is difficult to achieve with other methods.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Dr Florian Breider and Prof. Urs von Gunten, LTQE