Thesis
The effects of soil properties on the sorption of selected cephalosporin antibiotics
Washington State University
Master of Science (MS), Washington State University
2009
Handle:
https://hdl.handle.net/2376/100960
Abstract
Cephalosporin antibiotics are widely used and could be a reason for the development of antibiotic resistance in certain strains of pathogenic bacteria. This threat of cephalosporin antibiotics to the environment depends on their transport and bioavailability in soil and water environments, for which their sorption to soil is a key factor. Laboratory sorption experiments have not yet been conducted for the wide range of cephalosporins, including cephalothin, cefoxitin, and ceftriaxone. This study examined the sorption of these three antibiotics to soils exhibiting distinct physicochemical properties, such as organic carbon content, clay content, cation exchange capacity and pH. Batch equilibrium experiments were conducted to determine sorption properties for the three antibiotics each interacting with the three types of soil. Linear sorption coefficients (Kd) were obtained for each cephalosporin and soil combination. Cefoxitin was weakly sorbed to all soils, as its estimated Kd values ranged from 0.495 to 1.530 L/kg and were not highly affected by the soil properties examined. In contrast, ceftriaxone sorption to soil was affected by the soil properties; the estimated Kd values for ceftriaxone varied from 1.57 to 1,103.4 L/kg. This large range of Kd values between the three soils may result from the highly ionizable nature of ceftriaxone which would lead to an increased number of sorption mechanisms. Of all the antibiotics tested, cephalothin had the highest sorption propensity, with a Kd value of 7.442 L/kg for the soil with the lowest organic and clay content; complete sorption was observed for the other soils. The high sorption of cephalothin and ceftriaxone to soil suggests that these antibiotics are unlikely to leach to groundwater, but could undergo overland transport to surface waters as soilbound contaminants during erosion processes. On the other hand, cefoxitin would more readily leach due to poor sorption characteristics. Hence this study underlines the importance of collecting sorption data for individual antibiotics in order to better predict their fate and bioavailability in aqueous and terrestrial environments.
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Details
- Title
- The effects of soil properties on the sorption of selected cephalosporin antibiotics
- Creators
- Reuven Miropolskiy
- Contributors
- Jeffrey L. Ullman (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525292101842
- Language
- English
- Resource Type
- Thesis