ENVR 171 |
| Fluoroquinolone antibiotics are an emerging class of contaminants that have been detected in surface waters worldwide. Concern about their toxicological effects stems from past evidence of the widespread environmental impact of pesticides and hormones on non-targeted organisms. However, little is known about the chemical transformations and toxicological impacts of antibiotics in aquatic systems. We focused on the common fluoroquinolone antibiotic, ciprofloxacin, in an effort to understand its aquatic chemistry and its toxicological impact on photosynthetic aquatic organisms. The main objectives of our research were to quantify interactions with dissolved natural organic matter and effects on photosynthesis, including its role as a quinone-site inhibitor. Fluorescence quenching of ciprofloxacin was used to quantify its sorption equilibira and kinetics with different types of dissolved humic substances. Molecular dynamic simulations of its interactions with natural organic matter were performed to identify the functional groups important to these interactions. To identify the molecular target of photosynthetic inhibition by ciprofloxacin, isolated chloroplasts were investigated to assess which part of the photosystem is affected, while structure-activity analysis with known quinone-site inhibitors was performed to investigate a similar action by ciprofloxacin. These studies will contribute to a science-based assessment of the risk posed by ciprofloxacin to aquatic environments.
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General Papers
6:00 PM-8:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Environmental Chemistry |