Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, China.
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
J Hazard Mater. 2022 Oct 5;439:129668. doi: 10.1016/j.jhazmat.2022.129668. Epub 2022 Jul 22.
The migration of extracellular antibiotic resistance genes (eARGs) in porous media is an important pathway for ARGs to spread to the subsoil and aquifer. Biochar (BC) has been widely used to reduce the mobility of soil contaminants, however, its effect on the mobility of eARGs in porous media and the mechanisms are largely unknown. Herein, the effects of BCs synthesized from wheat straw and corn straw at two pyrolysis temperatures (300 °C and 700 °C) on the transport of plasmids-carried eARGs in sand column were investigated. The BC amendments all significantly decreased the mobility of eARGs in the porous medium, but the mechanism varied with pyrolysis temperature. The higher temperature BCs had a stronger irreversible adsorption of plasmids and greatly enhanced the attachment and straining effects on plasmids during transport, thus more effectively inhibited the mobility of eARGs. The lower temperature BCs had weaker adsorption, attachment, and straining effects on plasmids, but induced generation of hydroxyl radicals in the porous medium and thereby fragmented the plasmids and hindered the amplification of eARGs. These findings are of fundamental significance for the potential application of BC in controlling the vertical spread of eARGs in soil and vadose zones.
胞外抗生素抗性基因（eARGs）在多孔介质中的迁移是 ARGs 传播到土壤下层和含水层的重要途径。生物炭（BC）已被广泛用于降低土壤污染物的迁移性，然而，其对多孔介质中 eARGs 迁移性的影响及其机制在很大程度上尚不清楚。在此，研究了在两种热解温度（300°C 和 700°C）下由小麦秸秆和玉米秸秆合成的生物炭对砂柱中携带质粒的 eARGs 迁移的影响。BC 添加剂均显著降低了 eARGs 在多孔介质中的迁移性，但机制随热解温度而异。较高温度的 BC 对质粒具有更强的不可逆吸附作用，并在运输过程中极大地增强了对质粒的附着和筛选作用，从而更有效地抑制了 eARGs 的迁移性。较低温度的 BC 对质粒的吸附、附着和筛选作用较弱，但在多孔介质中诱导产生了羟基自由基，从而使质粒碎片化，并阻碍了 eARGs 的扩增。这些发现对于 BC 在控制土壤和包气带中 eARGs 垂直传播的潜在应用具有重要意义。
