Wehrhan Anne, Kasteel Roy, Simunek Jirka, Groeneweg Joost, Vereecken Harry
Agrosphere, ICG IV, Forschungszentrum Jülich GmbH, Leo-Brandt Str, 52425 Jülich, Germany.
J Contam Hydrol. 2007 Jan 5;89(1-2):107-35. doi: 10.1016/j.jconhyd.2006.08.002. Epub 2006 Oct 6.
Antibiotics, such as sulfadiazine, reach agricultural soils directly through manure of grazing livestock or indirectly through the spreading of manure or sewage sludge on the field. Knowledge about the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to the groundwater. Transport of (14)C-labelled sulfadiazine was investigated in disturbed soil columns at a constant flow rate of 0.26 cm h(-1) near saturation. Sulfadiazine was applied in different concentrations for either a short or a long pulse duration. Breakthrough curves of sulfadiazine and the non-reactive tracer chloride were measured. At the end of the leaching period the soil concentration profiles were determined. The peak maxima of the breakthrough curves were delayed by a factor of 2 to 5 compared to chloride and the decreasing limbs are characterized by an extended tailing. However, the maximum relative concentrations differed as well as the eluted mass fractions, ranging from 18 to 83% after 500 h of leaching. To identify relevant sorption processes, breakthrough curves of sulfadiazine were fitted with a convective-dispersive transport model, considering different sorption concepts with one, two and three sorption sites. Breakthrough curves can be fitted best with a three-site sorption model, which includes two reversible kinetic and one irreversible sorption site. However, the simulated soil concentration profiles did not match the observations for all of the used models. Despite this incomplete process description, the obtained results have implications for the transport behavior of sulfadiazine in the field. Its leaching may be enhanced if it is frequently applied at higher concentrations.
抗生素，如磺胺嘧啶，可通过放牧牲畜的粪便直接进入农业土壤，或通过在田间施用粪便或污水污泥间接进入。了解抗生素在土壤中的归宿对于评估这些化合物的环境风险至关重要，包括其可能向地下水的迁移。在接近饱和状态下，以0.26 cm h⁻¹的恒定流速，在扰动土柱中研究了¹⁴C标记的磺胺嘧啶的迁移。磺胺嘧啶以不同浓度进行短时间或长时间脉冲施用。测量了磺胺嘧啶和非反应性示踪剂氯化物的穿透曲线。在淋溶期结束时，测定了土壤浓度剖面。与氯化物相比，穿透曲线的峰值最大值延迟了2至5倍，下降段的特征是有一个延长的拖尾。然而，最大相对浓度以及洗脱质量分数也有所不同，淋溶500小时后，洗脱质量分数在18%至83%之间。为了确定相关的吸附过程，采用对流 - 弥散传输模型对磺胺嘧啶的穿透曲线进行拟合，该模型考虑了具有一个、两个和三个吸附位点的不同吸附概念。穿透曲线用三位点吸附模型拟合效果最佳，该模型包括两个可逆动力学吸附位点和一个不可逆吸附位点。然而，对于所有使用的模型，模拟的土壤浓度剖面与观测结果并不匹配。尽管对过程的描述并不完整，但所获得的结果对磺胺嘧啶在田间的迁移行为具有启示意义。如果频繁以较高浓度施用，其淋溶可能会增强。
