TY  - THES
AU  - Unold, Myriam
TI  - Experiments and numerical studies on transport of sulfadiazine in soil columns
VL  - 81
SN  - 1866-1793
PB  - Universität Bonn
VL  - Dr.
CY  - Jülich
M1  - PreJuSER-11708
SN  - 978-3-89336-663-7
T2  - Schriften des Forschungszentrums Jülich : Energie & Umwelt / Energy & Environment
SP  - XVI, 115 S.
PY  - 2010
N1  - Record converted from JUWEL: 18.07.2013
N1  - Univ. Bonn, Diss., 2010
AB  - Veterinary antibiotics like sulfadiazine (SDZ) are used in large amounts worldwide. Excreted as parent compounds or in the form of metabolites they reach agricultural soils mainly via spreading of manure or sewage sludge and may be transported to the groundwater. Recently, antibiotics have been detected in several environmental compartments leading to an increasing concern about their hazardous effects. To asses the leaching potential of SDZ from soils into groundwater, knowledge on its transport processes in soils is necessary. Also the transport of its metabolites as well as possible transformation processes have to be considered. In this work transport experiments at the column scale were performed. Therefore, SDZ and pig manure were used to analyze the governing processes that affect the transport of SDZ in disturbed and undisturbed soil columns of a loamy sand and a silty loam. For this purpose the Hydrus model (Šimůnek et al., 2008) has been adapted and applied to the observed BTCs and resident concentrations. The occurrence of transformation products in the outflow of repacked soil columns of both soils was investigated in experiments with a SDZ-solution. For the prediction of the $^{14}$C-distribution in the repacked soil columns, empirical approaches to describe irreversible sorption were tested. Furthermore the influence of flow rate and concentration/applied mass on SDZ transport was investigated and the respective experiments were simultaneously described with a common set of parameters. In transport experiments with pig manure, the effect of pig manure on the transport of SDZ as well as the transport behavior of the main metabolites of SDZ present in pig manure, N-Ac-SDZ and 4-OH-SDZ, were investigated. Without considering a known photo-degradation product transformation was very low in both investigated soils. In soil columns where most of the $^{14}$C was found near the soil surface, the prediction of the $^{14}$C-concentration profiles was improved by applying two empirical models other than first-order to predict irreversible sorption. The application of SDZ at a higher flow rate led to higher eluted masses and concentrations compared to experiments conducted at a lower flow rate. The simultaneous fitting process with a three site attachment/detachment model revealed that although the same sorption mechanisms seem to occur in all experiments, their characteristic time scales were different, especially under transient flow conditions. As the main difference between experiments with manure and SDZ-solution an accumulation of $^{14}$C in the upper soil layer was found in the experiments with manure. The modeling process revealed a high mobility of both SDZ and its transformation products. While the transformation of N-Ac-SDZ into SDZ was fast and no extended tailing of N-Ac-SDZ was observed, the transport behavior of 4-OH-SDZ was similar to SDZ.
LB  - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3
UR  - https://juser.fz-juelich.de/record/11708
ER  -