EESS talk on "Photochemical fate of lampricides in tributaries of the Great Lakes"
Event details
| Date | 26.03.2019 |
| Hour | 12:15 › 13:00 |
| Speaker |
Dr Christy Remucal, Associate professor, Aquatic Chemistry group, Civil & Environmental Engineering, College of Engineering, University of Wisconsin-Madison, USA - visiting professor LTQE née Christina Renée Keenan, leads the Aquatic Chemistry group at the University of Wisconsin, Madison and is the Director of the Water Science and Engineering Laboratory. She is a faculty member in the Department of Civil & Environmental Engineering, the Environmental Chemistry & Technology Program, and the Limnology & Marine Science Program. She holds an MS (2004) and a PhD (2009) in Civil & Environmental Engineering from the University of California, Berkeley, and a BS (2003) in Environmental Engineering Science from Massachusetts Institute of Technology. Before joining the UW faculty, Christy completed a post-doc in the Institute for Biogeochemistry and Pollutant Dynamics at the Swiss Federal Institute of Technology. |
| Location | |
| Category | Conferences - Seminars |
Abstract:
The lampricides, 3-triflouromethyl-4-nitrophenol (TFM) and 5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydrobenzamide (niclosamide) have been intentionally added to tributaries of the Great Lakes since the 1950’s to kill the invasive parasitic sea lamprey. In contrast to legacy contaminants and many chemicals of emerging concern, lampricides are directly added to the Great Lakes ecosystem. Despite their widespread and intentional use, the fate of TFM and niclosamide in the environment is still poorly understood. We performed laboratory experiments to assess the susceptibility of both compounds to direct and indirect photochemical degradation. While the direct photodegradation rates of TFM are orders of magnitude faster than those of niclosamide, both compounds eventually undergo dehalogenation during direct photolysis. The presence of dissolved organic matter increases the photodegradation rate of niclosamide through the production of a series of reactive oxidants. In contrast, TFM is not susceptible to indirect photolysis. In addition, we conducted two field campaigns to quantify TFM photolysis during lampricide applications in 2015 and 2016. From these two field campaigns we illustrate that TFM in both small and large systems may enter the Great Lakes with minimal photodegradation, which has important implications for Great Lakes ecosystems.
The lampricides, 3-triflouromethyl-4-nitrophenol (TFM) and 5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydrobenzamide (niclosamide) have been intentionally added to tributaries of the Great Lakes since the 1950’s to kill the invasive parasitic sea lamprey. In contrast to legacy contaminants and many chemicals of emerging concern, lampricides are directly added to the Great Lakes ecosystem. Despite their widespread and intentional use, the fate of TFM and niclosamide in the environment is still poorly understood. We performed laboratory experiments to assess the susceptibility of both compounds to direct and indirect photochemical degradation. While the direct photodegradation rates of TFM are orders of magnitude faster than those of niclosamide, both compounds eventually undergo dehalogenation during direct photolysis. The presence of dissolved organic matter increases the photodegradation rate of niclosamide through the production of a series of reactive oxidants. In contrast, TFM is not susceptible to indirect photolysis. In addition, we conducted two field campaigns to quantify TFM photolysis during lampricide applications in 2015 and 2016. From these two field campaigns we illustrate that TFM in both small and large systems may enter the Great Lakes with minimal photodegradation, which has important implications for Great Lakes ecosystems.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Urs von Gunten, LTQE-EPFL and Drinking Water Chemistry Group @EAWAG