The diffusive gradients in thin films (DGT) technique is an excellent method for investigating the dynamic processes of antibiotics in soils. However, whether it is applicable in antibiotic bioavailability assessment is yet to be disclosed. This study employed DGT to determine the antibiotic bioavailability in soil, and compared the results with plant uptake, soil solutions, and solvent extraction methods. DGT exhibited predictive capability for plant taking in antibiotics proved by the significant linear relationship between the DGT based concentration (C_DGT) and antibiotic concentration in roots and shoots. Although the performance of soil solution was acceptable based on linear relationship analysis, its stability was weaker than DGT. The results based on plant uptake and DGT indicated the bioavailable antibiotic contents in different soils were inconsistent because of the distinct mobility and resupply of sulphonamides and trimethoprim in different soils, as represented by K_d and R_ds, which were affected by soil properties. Plant species played an important role in antibiotic uptake and translocation. Antibiotic uptake by plants depends on antibiotic, plant and soil. These results confirmed the capability of DGT in determining antibiotic bioavailability for the first time. This work provided a simple and powerful tool for environmental risk evaluation of antibiotics in soils.

薄膜扩散梯度 (DGT) 技术是研究土壤中抗生素动态过程的绝佳方法。然而，它是否适用于抗生素生物利用度评估尚未公开。本研究采用 DGT 测定土壤中抗生素的生物利用度，并将结果与​​植物吸收、土壤溶液和溶剂提取方法进行比较。DGT 表现出对植物吸收抗生素的预测能力，这由基于 DGT 的浓度 ( C _DGT) 和根和芽中的抗生素浓度。虽然基于线性关系分析，土壤溶液的性能是可以接受的，但其稳定性弱于DGT。基于植物吸收和 DGT 的结果表明，由于不同土壤中磺胺类药物和甲氧苄氨嘧啶的不同流动性和再供给，不同土壤中生物可利用的抗生素含量不一致，如 K d_和R ds_所示, 受土壤性质的影响。植物种类在抗生素摄取和转运中起着重要作用。植物对抗生素的吸收取决于抗生素、植物和土壤。这些结果首次证实了 DGT 在确定抗生素生物利用度方面的能力。这项工作为土壤中抗生素的环境风险评估提供了一个简单而强大的工具。