Antibiotics as Emerging Environmental Pollutants : Mechanisms of Interactions with Soil Particles
Event details
| Date | 09.03.2009 |
| Hour | 16:15 |
| Speaker | Ludmilla Aristilde, LGIT, Grenoble, France |
| Location |
GR B30
|
| Category | Conferences - Seminars |
The extensive use of antibiotics in both human and veterinary medicine has led to the application of antibiotic-containing wastes to agricultural soils and continuous discharge of antibiotics in receiving waters. Concerns about antibiotics as “emerging” environmental contaminants include their potential inhibition of important soil microbial processes and adverse effects on sensitive aquatic organisms as they are known to resist biodegradation, to adsorb strongly to soil particles, and to persist in aquatic sediments. Much still remains unknown about the specific mechanisms influencing the fate of antibiotics in natural soils, knowledge that is prerequisite to the comprehensive risk assessment of antibiotics in the environment. The focus of the current studies was to employ a combination of experimental and modeling techniques to elucidate the molecular-scale interactions of 1. Ciprofloxacin (Cipro), a fluoroquinolone antibiotic with humic substances (HS) and 2. Oxytetracycline (Oxy), a tetracycline antibiotic with a smectite clay. For the Cipro-HS systems, the sorption capacity of HS of different chemical composition was determined via fluorescence quenching spectroscopy and molecular modeling of Cipro-metal-HS adsorbates indicated the potential chemical interactions important for their stable conformations. For the Oxy-clay systems, the functional groups involved in the binding were examined via NMR and IR spectroscopic analyses and the conformations of the clay-metal-antibiotic complex were determined by monitoring mixed layer structures in recorded X-ray diffraction patterns and performing molecular simulations of stable configurations. The obtained results led to a mechanistic depiction of the sequestration of antibiotics within soil particles and provided for a better prediction of the environmental fate of antibiotics.
Practical information
- General public
- Free
Contact
- A. Berne