title: Competitive adsorption/desorption of tetracycline, oxytetracycline and chlortetracycline on two acid soils: Stirred flow chamber experiments.
abstract: The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred flow chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: David
authors.initials: D
authors.lastname: Fernández-Calviño
authors.affiliation: Soil Science and Agricultural Chemistry Area, Faculty of Sciences, Campus Univ. Ourense, University of Vigo, Galicia, Spain.
authors.forename: Alipio
authors.initials: A
authors.lastname: Bermúdez-Couso
authors.affiliation: Soil Science and Agricultural Chemistry Area, Faculty of Sciences, Campus Univ. Ourense, University of Vigo, Galicia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Arias-Estévez
authors.affiliation: Soil Science and Agricultural Chemistry Area, Faculty of Sciences, Campus Univ. Ourense, University of Vigo, Galicia, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Nóvoa-Muñoz
authors.affiliation: Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Campus Univ. Lugo, University of Santiago de Compostela, Galicia, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Fernández-Sanjurjo
authors.affiliation: Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Campus Univ. Lugo, University of Santiago de Compostela, Galicia, Spain.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Álvarez-Rodríguez
authors.affiliation: Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Campus Univ. Lugo, University of Santiago de Compostela, Galicia, Spain. Electronic address: avelino.nunez@usc.es.
authors.forename: Avelino
authors.initials: A
authors.lastname: Núñez-Delgado
mesh_terms: D000143:Acids; D000327:Adsorption; D000538:Aluminum Silicates; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry; D002751:Chlortetracycline / Q000032:analysis / Q000737:chemistry; D000077215:Clay; D007700:Kinetics; D008956:Models, Chemical; D010118:Oxytetracycline / Q000032:analysis / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013752:Tetracycline / Q000032:analysis / Q000737:chemistry*
chemical_list: D000143:Acids; D000538:Aluminum Silicates; D000900:Anti-Bacterial Agents; D012987:Soil; D012989:Soil Pollutants; D013752:Tetracycline; D000077215:Clay; D002751:Chlortetracycline; D010118:Oxytetracycline
keywords: Acid soils; Competitive adsorption/desorption; Environmental pollution; Stirred flow chamber; Tetracyclines