Sequestration of veterinary medicines in soils

第一阶段的研究结果表明，长期(7个月)，SDZ及其羟基代谢物在土壤中的去向决定着土壤中SDZ及其代谢物的去向。有人假设这种隔离是由扩散控制的，因此应该是可逆的，而N-ac SDZ由于其快速降解和氨基的封闭而没有大量的隔离。到目前为止，所有的实验都是在没有植物的情况下使用均质土壤进行的。因此，第二阶段的目标是：(I)按照中央模型的要求，阐明SDZ代谢物对单个SDZ代谢物的吸附和封存；(Ii)评估导致土壤中残留部分形成的吸附/封存机制；(Iii)检验SDZ及其羟基代谢物可能从这些残留物中重新动员并由此在土壤中产生长期影响的假说；以及(Iv)阐明根际和田间条件对SDZ和DIF在中央中间层和田间实验中的封存动态的作用。

The results of the first phase suggested that there is a residual fraction which controls the sequestration and thus the fate of SDZ and its OH metabolite in soil in the long-term run (>7 months). It has been hypothesized that this sequestration is controlled by diffusion and should thus be reversible, whereas N-Ac SDZ is not sequestered in significant amount due to its fast degradation and blocking of the amino group. Up to now, all experiments have been performed using homogenized soil in the absence of plants. The objectives of this second phase are therefore (i) to elucidate the sorption and sequestration of the individual SDZ metabolites as required by the central model, (ii) to evaluate the sorption/sequestration mechanisms responsible for the formation of a residual fraction in soil, (iii) to test the hypothesis that SDZ and its OH-metabolite may be re-mobilized from this residual fraction and thus induce effects in soil in the long-term, and (iv) to elucidate the role of the rhizosphere and field conditions for the sequestration dynamics of both SDZ and DIF in the central mesocosm and field experiments.