Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing 210023, China.
Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA.
Sci Total Environ. 2016 Dec 15;573:1630-1637. doi: 10.1016/j.scitotenv.2016.09.164. Epub 2016 Sep 29.
Understanding the fate and transport of antibiotics in porous media can help reduce their contamination risks to soil and groundwater systems. In this work, batch and column experiments were conducted to determine the interactions between two representative antibiotics, sulfacetamide (SA) and levofloxacin (LEV), and sand porous media under various solution pH, humic acid (HA) concentration, grain size, and moisture content conditions. Batch sorption experimental results indicated that the sand had relatively strong bonding affinity to LEV, but little sorption of SA under different pH, HA concentration, grain size conditions. Results from the packed sand column experiments showed that SA had extremely high mobility in the porous media for all combinations of pH, HA concentration, grain size, and moisture content. The mass recovery of SA was higher than 98.5% in all the columns with the exception of the one packed with fine sand (97.2%). The retention of LEV in the columns was much higher and the recovery rates ranged from 0% to 71.1%. Decreases in solution pH, HA concentration, grain size, or moisture content reduced the mobility of LEV in the columns under the tested conditions. These results indicated that type of antibiotics and environmental conditions also played an important role in controlling their fate and transport in porous media. Mathematical models were applied to simulate and interpret experimental data, and model simulations described the interactions between the two antibiotics and sand porous media very well. Findings from this study elucidated the key factors and processes controlling the fate of SA and LEV in porous media, which can inform the prediction and assessment of the environmental risks of antibiotics.
了解抗生素在多孔介质中的归趋和迁移转化规律有助于降低其对土壤和地下水系统的污染风险。本工作通过批实验和柱实验研究了两种典型抗生素（磺胺醋酰和左氧氟沙星）在不同溶液 pH 值、腐殖酸（HA）浓度、粒径和含水量条件下与沙质多孔介质的相互作用。批吸附实验结果表明，在不同 pH 值、HA 浓度和粒径条件下，沙质多孔介质对 LEV 具有较强的结合亲和力，而对 SA 的吸附作用较小。填砂柱实验结果表明，在所有 pH 值、HA 浓度、粒径和含水量组合条件下，SA 在多孔介质中具有极高的迁移性。除了细砂（97.2%）填充的柱子外，所有柱子中 SA 的质量回收率均高于 98.5%。LEV 在柱子中的保留率较高，回收率范围为 0%至 71.1%。在测试条件下，溶液 pH 值、HA 浓度、粒径或含水量的降低均会降低 LEV 在柱子中的迁移性。这些结果表明，抗生素的类型和环境条件也在控制其在多孔介质中的归趋和迁移转化中起着重要作用。应用数学模型对实验数据进行模拟和解释，模型模拟很好地描述了两种抗生素与沙质多孔介质之间的相互作用。本研究结果阐明了控制 SA 和 LEV 在多孔介质中命运的关键因素和过程，可为抗生素的环境风险预测和评估提供信息。
