title: Transformation and sorption of the veterinary antibiotic sulfadiazine in two soils: a short-term batch study.
abstract: The worldwide use of veterinary antibiotics poses a continuous threat to the environment. There is, however, a lack of mechanistic studies on sorption and transformation processes for environmental assessment in soils. Two-week batch sorption experiments were performed with the antibiotic sulfadiazine (SDZ) in the plow layer and the subsoil of a loamy sand and a silty loam. The sorption and transformation parameters of SDZ and its main transformation products N1-2-(4-hydroxypyrimidinyl) benzenesulfanilamide (4-OH-SDZ) and 4-(2-iminopyrimidin-1(2H)-yl)aniline (An-SDZ) were estimated using a global optimization algorithm. A two-stage, one-rate sorption model combined with a first-order transformation model adequately described the batch data. Sorption of SDZ was nonlinear, time-dependent, and affected by pH, with a higher sorption capacity for the loamy sand. Transformation of SDZ into 4-OH-SDZ occurred only in the liquid phase, with half-life values of 1 month in the plow layers and 6 months in the subsoils. Under the exclusion of light, An-SDZ was formed in substantial amounts in the silty loam only, with liquid phase half-life values of 2 to 3 weeks. Despite the rather large parameter uncertainties, which may be reduced using additional information obtained from sequential solid phase extraction, the proposed method provides a framework to assess the fate of antibiotics in soils.
authors.affiliation: Agrosphere Institute, ICG 4, Forschungszentrum Julich GmbH, Leo Brandtstrasse, D-52425 Julich, Germany. r.kasteel@fz-juelich.de
authors.forename: Roy
authors.initials: R
authors.lastname: Kasteel
authors.forename: Cho Miltin
authors.initials: CM
authors.lastname: Mboh
authors.forename: Myriam
authors.initials: M
authors.lastname: Unold
authors.forename: Joost
authors.initials: J
authors.lastname: Groeneweg
authors.forename: Jan
authors.initials: J
authors.lastname: Vanderborght
authors.forename: Harry
authors.initials: H
authors.lastname: Vereecken
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D001711:Biotransformation; D002250:Carbon Radioisotopes; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D008956:Models, Chemical; D012987:Soil / Q000032:analysis*; D013411:Sulfadiazine / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013997:Time Factors; D019155:Veterinary Drugs / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D012987:Soil; D019155:Veterinary Drugs; D013411:Sulfadiazine