Dep. of Soil and Water Science, Faculty of Agriculture, Food and Environment, The Hebrew Univ. of Jerusalem, Rehovot, Israel.
J Environ Qual. 2011 May-Jun;40(3):942-8. doi: 10.2134/jeq2010.0446.
Pharmaceutical compounds (PCs) and dissolved organic matter (DOM) are co-introduced into soils by irrigation with reclaimed wastewater. We targeted carbamazepine (CBZ) as a model compound to study the tertiary interactions between relatively polar PCs, DOM, and soil. Sorption-desorption behavior of CBZ was studied with bulk clay soil and the corresponding clay size fraction in the following systems: (i) without DOM, (ii) co-introduced with DOM, and (iii) pre-adsorption of DOM before CBZ introduction. Sorption of the DOM to both sorbents was irreversible and exhibited pronounced sorption-desorption hysteresis. Carbamazepine exhibited higher sorption affinity and nonlinearity, and a higher degree of desorption hysteresis with the bulk soil than the corresponding clay size fraction. This was probably due to specific interactions with polar soil organic matter fractions that are more common in the bulk soil. Co-introduction of CBZ and DOM to the soil did not significantly affect the sorption behavior of CBZ; however, following pre-adsorption of DOM by the bulk soil, an increase in sorption affinity and decrease in sorption linearity were observed. In this latter treatment, desorption hysteresis of CBZ was significantly increased for both sorbents. We hypothesize that this was due to either strong chemical interactions of CBZ with the adsorbed DOM or physical encapsulation of CBZ in DOM-clay complexes. Based on this study, we suggest that DOM facilitates stronger interactions of polar PCs with the solid surface. This mechanism can reduce PC desorption ability in soils.
药品化合物（PCs）和溶解有机物（DOM）通过再生废水灌溉共同引入土壤。我们以卡马西平（CBZ）为模型化合物，研究相对极性的 PCs、DOM 和土壤之间的三级相互作用。在以下系统中研究了 CBZ 的吸附-解吸行为：（i）没有 DOM，（ii）与 DOM 共同引入，（iii）在引入 CBZ 之前预吸附 DOM。DOM 在两种吸附剂上的吸附都是不可逆的，表现出明显的吸附-解吸滞后。与相应的粘土粒径部分相比，CBZ 在大土壤上表现出更高的吸附亲和力和非线性，以及更高程度的解吸滞后。这可能是由于与大土壤中更常见的极性土壤有机物质部分的特定相互作用所致。CBZ 和 DOM 共同引入土壤不会显著影响 CBZ 的吸附行为；然而，在大土壤预先吸附 DOM 后，观察到吸附亲和力增加，吸附线性度降低。在后一种处理中，两种吸附剂的 CBZ 解吸滞后都显著增加。我们假设这是由于 CBZ 与吸附的 DOM 之间的强化学相互作用或 CBZ 在 DOM-粘土复合物中的物理封装所致。基于这项研究，我们认为 DOM 促进了极性 PCs 与固体表面之间更强的相互作用。这种机制可以降低土壤中 PC 的解吸能力。
