R4 AM Occurrence and Fate of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in Ballroom 4

(BEL-1117-810385) Partitioning of ciprofloxacin in aquatic systems.

Belden, J¹, Maul, J¹, Lydy, M¹, ¹ Southern Illinois University, Carbondale, IL, USA

ABSTRACT- Fluoroquinolone antibiotics are of environmental concern due to wide usage, low degradability by microorganisms, and detection in stream and river water. This class of antibiotics has high water-soil partitioning coefficients, high water solubility, and is highly photodegradable; however, little else is known about the fate of these chemicals in aquatic environments. The objective of this research was to study the partitioning of a model fluoroquinolone, ciprofloxacin, in aquatic systems. Specifically, partitioning of ¹⁴C-ciprofloxacin (cipro) was measured between water and several other matrices that may be present within aquatic systems including sediment, fresh leaf material, degraded leaf material, algae, and particulate matter. Cipro accumulated on each matrix tested with varying magnitudes of accumulation. For example, cipro accumulated on fresh leaf material with concentrations on the leaf 300 times that found in the water while for degraded leaf material, concentrations were nearly 20,000 times the concentration of surrounding water indicating that specific microbial niches may be of greater risk of impact than others. The desorption potential also varied widely between matices. For instance, desorption from sediment was nearly negligible while desorption from leaf material was clearly demonstrated with comparatively little hysteresis. Thus, accumulation in some matrices may serve as a sink allowing little bioavailability, while absorption to other matrices may result in greater potential environmental impact.

Key words: antibiotic, fate, ciprofloxacin