The Brazilian semiarid region is subjected to irregular rainfall, prolonged droughts, and high temperatures, hampering the surface water accumulation. The water access is restricted to the alluvium in the valleys, which are used for cattle and poultry livestock development. These activities trigger the excessive use of veterinary antibiotics, which are not fully metabolized by animal's organisms. For this reason, antibiotics reach sediment surfaces and promote deterioration of groundwater quality. This work aims to evaluate the sorption potential of Sulfadiazine (SDZ) and to understand the dynamics of water transfer processes in a typical alluvial deposit of the Capibaribe River, in the Agreste of Pernambuco. The sedimentological characterization was performed by Miall's Code, defining four lithofacies (Scm, Scm,b, Gcm,o, Scm,o). According to the particle size distribution curve, the Scm lithofacies had the highest number of fine particles and organic matter. Kinetics and isotherms experiments allowed the analyses of SDZ sorption. Kinetics sorption showed an equilibrium tendency after 40 h and was better described by a second-order model, while sorption isotherms better fitted the Freundlich model. SDZ sorption was low, being slightly higher in the Scm lithofacies because organic matter and clay contents affected the SDZ interaction in sediments. Consequently, SDZ offers a real risk of groundwater contamination due to its low sorption. The structural heterogeneity of the alluvial deposit influenced the spatial distribution of water storage under unsaturated conditions and provided the emergence of preferential flows. The solute dynamic might follow a similar behavior of the water flow, due to the low retention of Sulfadiazine in the soil. The influence of preferential flows in the transport of contaminants will require several experimental and numerical actions in future research.

巴西半干旱地区遭受不规则降雨、长期干旱和高温，阻碍了地表水的积累。取水仅限于山谷中的冲积层，这些冲积层用于牛和家禽畜牧业的发展。这些活动引发了兽用抗生素的过度使用，而兽用抗生素并未完全被动物生物体代谢。出于这个原因，抗生素会到达沉积物表面并促进地下水质量的恶化。这项工作旨在评估磺胺嘧啶 (SDZ) 的吸附潜力，并了解伯南布哥州阿格雷斯特的 Capibaribe 河典型冲积沉积物中的输水过程动力学。沉积学特征由 Miall's Code 执行，定义了四种岩相（Scm、Scm、b、Gcm、o、Scm，o）。根据粒度分布曲线，Scm岩相中细颗粒和有机质数量最多。动力学和等温线实验允许对 SDZ 吸附进行分析。动力学吸附在 40 小时后显示出平衡趋势，可以用二阶模型更好地描述，而吸附等温线更符合 Freundlich 模型。SDZ 吸附较低，在 Scm 岩相中略高，因为有机质和粘土含量影响沉积物中 SDZ 的相互作用。因此，由于其低吸附性，SDZ 存在地下水污染的真正风险。冲积矿床的结构异质性影响了非饱和条件下储水的空间分布，并提供了优先流的出现。由于磺胺嘧啶在土壤中的保留率低，溶质动力学可能遵循类似的水流行为。在未来的研究中，优先流对污染物传输的影响将需要进行一些实验和数值操作。