66-6 Factors Influencing Tetracycline Sorption by Smectite Clays from Water

Poster Number 15

See more from this Division: Joint Sessions
See more from this Session: Organic Contaminants in Water, Soil and Sediments: Sources, Interactions and Ecological Impacts (Posters)

Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E

Yunjie Ding1, Brian Teppen1, Stephen Boyd1 and Hui Li2, (1)Department of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI
(2)Department of Crop and Soil Sciences, Michigan State University, East Lansing, MI
Abstract:
Tetracyclines are a class of antimicrobials that have been extensively used to improve human and veterinary health. A large portion of tetracyclines used by humans and animals can be released into the environment, raising concerns regarding the potential risks to ecosystems and environmental quality. Sorption by soils is a determinant controlling transport, fate and hence exposure in the environment. Soil mineral fractions are the dominant sorptive domains for retaining these compounds. In this study, sorption of tetracycline by K+- and Ca2+-saturated smectite clays was measured using a batch equilibration method. Sorption manifested nonlinear isotherms, and was strongly suppressed by the presence of high levels of inorganic cations (e.g., K+ and Ca2+) in solution. Sorption of tetracycline by K-, and Ca-smectite was concomitant with the release of K+ and Ca2+ from the clays, suggesting that cation exchange process is responsible for the sorption of tetracycline. X-ray diffraction patterns showed that the interlayer distances of smectite clays increased as tetracycline sorption increased, and gradually approached a constant basal spacing of 17.5 to 18 Å. These results indicate that the clay-sorbed tetracyclines are intercalated in interlayer regions.

See more from this Division: Joint Sessions
See more from this Session: Organic Contaminants in Water, Soil and Sediments: Sources, Interactions and Ecological Impacts (Posters)