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SUMMARY:Understanding the influence of dissolved organic matter on the pho
 tochemical fate of the antibiotic sulfadimethoxine
DTSTART:20090914T161500
DTSTAMP:20260924T121054Z
UID:5ae0077e888b5258889f947e0381e93c4d0a3c4c4c178190e075ba30
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Jennifer Guerard \nSulfadimethoxine (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 degradati
 on in natural sunlit surface waters\, but the role dissolved organic matte
 r (DOM) plays in its\nphotodegradation is not well understood.\nOur result
 s show that SDM photodegradation is rapid in water from a eutrophic catfis
 h pond at the USDA facility in Stoneville\, Mississippi\, while no enhance
 ment of photodegradation was observed in a nearby stream (Deer Creek). We 
 attribute these disparate results to DOM composition\, whereby dissolved o
 rganic matter originating from highly eutrophic water bodies is a better S
 DM photosensitizer. Experiments conducted concurrently using respective mi
 crobially (Pony Lake\,\nAntarctica) and terrestrially (Suwannee River) der
 ived reference fulvic acids corroborate these findings. Photo‐derivative
 s assayed by mass spectrometry reveal the same major SDM photoproducts in 
 the presence and absence of DOM. Fulvic acids from both the catfish pond w
 aters\nand 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 t
 he DOM source continuum (microbial v. terrestrial).\nOverall\, the DOM sou
 rce composition may play a significant role in the photochemical fate of c
 ompounds in aquatic systems.
LOCATION:GR B3 30
STATUS:CONFIRMED
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