Understanding the influence of dissolved organic matter on the photochemical fate of the antibiotic sulfadimethoxine
Event details
| Date | 14.09.2009 |
| Hour | 16:15 |
| Speaker | Dr Jennifer Guerard |
| Location |
GR B3 30
|
| Category | Conferences - Seminars |
Sulfadimethoxine (SDM) is an antibiotic often used in combination with ormetoprim to prevent the spread of disease in freshwater aquaculture. It is known to undergo photochemical degradation in natural sunlit surface waters, but the role dissolved organic matter (DOM) plays in its
photodegradation is not well understood.
Our results show that SDM photodegradation is rapid in water from a eutrophic catfish pond at the USDA facility in Stoneville, Mississippi, while no enhancement of photodegradation was observed in a nearby stream (Deer Creek). We attribute these disparate results to DOM composition, whereby dissolved organic matter originating from highly eutrophic water bodies is a better SDM photosensitizer. Experiments conducted concurrently using respective microbially (Pony Lake, Antarctica) and terrestrially (Suwannee River) derived reference fulvic acids corroborate these findings. Photo‐derivatives assayed by mass spectrometry reveal the same major SDM photoproducts in the presence and absence of DOM. Fulvic acids from both the catfish pond waters and Deer Creek were isolated and characterized. While these waters are located in very close proximity to each other, their fulvic isolates show characteristics similar to IHSS reference samples as end members of the DOM source continuum (microbial v. terrestrial).
Overall, the DOM source composition may play a significant role in the photochemical fate of compounds in aquatic systems.
Our results show that SDM photodegradation is rapid in water from a eutrophic catfish pond at the USDA facility in Stoneville, Mississippi, while no enhancement of photodegradation was observed in a nearby stream (Deer Creek). We attribute these disparate results to DOM composition, whereby dissolved organic matter originating from highly eutrophic water bodies is a better SDM photosensitizer. Experiments conducted concurrently using respective microbially (Pony Lake, Antarctica) and terrestrially (Suwannee River) derived reference fulvic acids corroborate these findings. Photo‐derivatives assayed by mass spectrometry reveal the same major SDM photoproducts in the presence and absence of DOM. Fulvic acids from both the catfish pond waters and Deer Creek were isolated and characterized. While these waters are located in very close proximity to each other, their fulvic isolates show characteristics similar to IHSS reference samples as end members of the DOM source continuum (microbial v. terrestrial).
Overall, the DOM source composition may play a significant role in the photochemical fate of compounds in aquatic systems.
Practical information
- General public
- Free
Contact
- M. Sudki