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SUMMARY:Antibiotics as Emerging Environmental Pollutants : Mechanisms of I
 nteractions with Soil Particles
DTSTART:20090309T161500
DTSTAMP:20260610T154842Z
UID:6e904cbc64a7b7cae9b2f4050ab690db431d323400e2f3d48015e9c1
CATEGORIES:Conferences - Seminars
DESCRIPTION:Ludmilla Aristilde\, LGIT\, Grenoble\, France\nThe extensive u
 se of antibiotics in both human and veterinary medicine has led to the app
 lication of antibiotic-containing wastes to agricultural soils and continu
 ous discharge of antibiotics in receiving waters. Concerns about antibioti
 cs as “emerging” environmental contaminants include their potential in
 hibition of important soil microbial processes and adverse effects on sens
 itive aquatic organisms as they are known to resist biodegradation\, to ad
 sorb strongly to soil particles\, and to persist in aquatic sediments. Muc
 h still remains unknown about the specific mechanisms influencing the fate
  of antibiotics in natural soils\, knowledge that is prerequisite to the c
 omprehensive risk assessment of antibiotics in the environment. The focus 
 of the current studies was to employ a combination of experimental and mod
 eling techniques to elucidate the molecular-scale interactions of 1. Cipro
 floxacin (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 spectroscop
 y and molecular modeling of Cipro-metal-HS adsorbates indicated the potent
 ial chemical interactions important for their stable conformations. For th
 e Oxy-clay systems\, the functional groups involved in the binding were ex
 amined via NMR and IR spectroscopic analyses and the conformations of the 
 clay-metal-antibiotic complex were determined by monitoring mixed layer st
 ructures in recorded X-ray diffraction patterns and performing molecular s
 imulations of stable configurations. The obtained results led to a mechani
 stic depiction of the sequestration of antibiotics within soil particles a
 nd provided for a better prediction of the environmental fate of antibioti
 cs.  
LOCATION:GR B30
STATUS:CONFIRMED
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