Modelling of the Environmental Fate and Effects of Veterinary Medicines in Soil under Field Conditions

在第二阶段，我们模拟了SDZ及其主要代谢物在田间温度和水分条件下的去向和影响，可以解释大部分观测到的温度和瞬时水分影响的变化。对于这些模拟，使用了从恒定条件下的微观和介观实验中确定的所建立的模型结构和动力学速率常数。然而，相关过程的隐含不确定性阻碍了对SDZ在人工土壤中命运的先验预测，以及由此对硝化作用和抗性基因选择的影响。SDZ和4-OH-SDZ从残留物和生物终点的释放，如古生菌的氨氧化丰度和活性，似乎都受到土壤水分条件的影响，但其影响方式尚不清楚。在研究单元的第三阶段，我们将在野外条件下测试命运与效应耦合模型的有效性。在田间和温室试验的基础上，分析不同湿度和温度对SDZ转化和封存过程的影响，以及对硝化作用和抗性基因选择的影响。将在干燥和再湿循环下模拟命运和影响过程，并与静态湿度条件进行比较。将确定最敏感的过程和参数，并通过蒙特卡洛分析量化预测的不确定性。

In the 2nd phase, we simulated fate and effects of SDZ and its main metabolites under consideration of field temperature and moisture conditions and could explain a large part of the observed variability by temperature and instantaneously moisture effects. For these simulations, the established model structure and kinetic rate constants as determined from micro- and mesocosm experiments under constant conditions were used. However, implicit uncertainties of relevant processes prevent a priori predictions of SDZ fate in manured soil and resulting effects on nitrification and resistance gene selection. Both the release of SDZ and 4-OH-SDZ from the residual fraction and biotic endpoints such as abundance and activity of ammonium oxidizing archaea seems to be influenced by soil moisture conditions in a not yet well understood manner. In the 3rd phase of our Research Unit we will test the validity of the coupled fate and effect model under field conditions. The influence of variable moisture and temperature on transformation and sequestration processes of SDZ as well as on resulting effects on nitrification and resistance gene selection will be analysed based on field and greenhouse experiments. Fate and effect processes will be simulated under drying and re-wetting cycles and compared to static moisture conditions. Most sensitive processes and parameters will be identified and uncertainties of predictions quantified by Monte-Carlo analysis.