College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, PR China; Shenzhen Research Institute of Guangdong Ocean University, Shenzhen 518108, PR China.
College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, PR China.
Sci Total Environ. 2023 Jul 10;881:163410. doi: 10.1016/j.scitotenv.2023.163410. Epub 2023 Apr 12.
Tetracycline pollution is common in Chinese arable soils, and vermicomposting is an effective approach to accelerate tetracycline bioremediation. However, current studies mainly focus on the impacts of soil physicochemical properties, microbial degraders and responsive degradation/resistance genes on tetracycline degradation efficiencies, and limited information is known about tetracycline speciation in vermicomposting. This study explored the roles of epigeic E. fetida and endogeic A. robustus in altering tetracycline speciation and accelerating tetracycline degradation in a laterite soil. Both earthworms significantly affected tetracycline profiles in soils by decreasing exchangeable and bound tetracycline but increasing water soluble tetracycline, thereby facilitating tetracycline degradation efficiencies. Although earthworms increased soil cation exchange capacity and enhanced tetracycline adsorption on soil particles, the significantly elevated soil pH and dissolved organic carbon benefited faster tetracycline degradation, attributing to the consumption of soil organic matter and humus by earthworms. Different from endogeic A. robustus which promoted both abiotic and biotic degradation of tetracycline, epigeic E. foetida preferently accelerated abiotic tetracyline degradation. Our findings described the change of tetracycline speciation during vermicompsiting process, unraveled the mechanisms of different earthworm types in tetracycline speciation and metabolisms, and offered clues for effective vermiremediation application at tetracycline contaminated sites.
在中国农田土壤中，四环素污染很常见，而蚯蚓堆肥是加速四环素生物修复的有效方法。然而，目前的研究主要集中在土壤物理化学性质、微生物降解菌和响应降解/抗性基因对四环素降解效率的影响上，对于蚯蚓堆肥中四环素的形态变化知之甚少。本研究探讨了表栖型赤子爱胜蚓（Eisenia fetida）和内栖型威廉环毛蚓（Pheretima guillelmi）在改变红壤中四环素形态和加速四环素降解中的作用。这两种蚯蚓都通过降低可交换态和结合态四环素，增加水溶性四环素，从而显著影响土壤中四环素的形态，促进四环素的降解效率。尽管蚯蚓增加了土壤阳离子交换能力，并增强了四环素在土壤颗粒上的吸附，但显著升高的土壤 pH 值和溶解有机碳有利于更快地降解四环素，这归因于蚯蚓对土壤有机质和腐殖质的消耗。与促进四环素非生物和生物降解的内栖型威廉环毛蚓不同，表栖型赤子爱胜蚓更优先促进四环素的非生物降解。本研究描述了四环素在蚯蚓堆肥过程中的形态变化，揭示了不同蚯蚓类型在四环素形态和代谢中的作用机制，为四环素污染场地的有效蚯蚓修复应用提供了线索。
