摘要

       最近，人工湿地中抗生素和抗生素抗性基因（ARG）的命运受到了更多关注。本研究旨在评估水力流动方向（下流或上流）和基质类型（砖瓦砾或牡蛎壳）对从猪废水中去除抗生素和 ARG 的影响。对于抗生素的去除，所有处理在两个手术阶段都可以去除84%以上的土霉素和二氟沙星。由于砖的特性，砖基柱具有更强的抗生素去除能力，包括大孔隙率和微孔尺寸以及 32% 的 Fe2O3。表层土壤往往比二氟沙星吸附更多的土霉素，这与砖和牡蛎壳相反。对于 ARGs 去除，1 类整合子的四环素抗性基因 (tet) 和整合酶基因的去除效率为 33.2% 至 99.1%，处理之间没有显着差异（p > 0.05）。然而，上流处理出水的 ∑tet 相对丰度大多高于进水，这表明存在向环境中释放与细菌总数成比例的相对较多的抗生素抗性细菌的风险。与抗生素浓度显着相关，表层土壤中 ARGs 的相对丰度随着所有处理时间的推移而增加。我们的结果表明，使用人工湿地去除抗生素受基质类型的影响很大，而污水和土壤中 ARG 相对丰度的变化取决于水流方向。

       The fate of antibiotics and antibiotic resistance genes (ARGs) in constructed wetlands has received more concerns recently. This study aimed to assess the influence of hydraulic flow direction (down-flow or up-flow) and substrate type (brick rubble or oyster shell) on removal of antibiotics and ARGs from swine wastewater. For antibiotic removal, all of treatments can remove more than 84% of oxytetracycline and difloxacin during two stages of operation. Brick-based columns had stronger antibiotic removal capacity due to properties of brick, including large porosity and micropore size and 32% of Fe2O3. The surface soils tended to adsorb much more oxytetracycline than difloxacin, as was opposite to brick and oyster shell. For ARGs removal, the removal efficiencies of tetracycline-resistance genes (tet) and integrase gene of Class 1 integrons ranged from 33.2 to 99.1%, without significant difference among treatments (p > 0.05). However, most of ∑tet relative abundances in effluents of up-flow treatments were higher than those in influents, which indicated a risk to release relatively more antibiotic-resistant bacteria in proportion to total bacteria into environment. Significantly correlated with antibiotic concentrations, ARGs relative abundances in surface soils increased as the time progressed for all the treatments. Our results demonstrate that antibiotic removal using constructed wetlands is greatly affected by substrate type, whereas variation of ARG relative abundances in effluents and soils are determined by hydraulic flow direction.

https://www.sciencedirect.com/science/article/abs/pii/S1385894716313535