土壤中单一及复合抗生素的降解及微生物响应

基于LC-MS/MS、MicroRESP^TM等技术，对比了磺胺二甲嘧啶（SM2）和强力霉素（DOX）在单一和共存条件下，在青紫泥和小粉土中的短期降解及土壤微生物代谢特征.结果表明，单一条件下，小粉土中SM2和DOX的3d和7d降解率总体高于青紫泥，SM2和DOX共存条件下可对土壤中二者的短期降解产生一定抑制，这种抑制作用在小粉土中更为明显.抗生素对土壤微生物代谢的影响与其赋存时间及土壤类型有关.在供试浓度10~20mg/kg下，SM2和DOX在单一和复合条件下总体是促进土壤微生物代谢，但影响随赋存时间增加而减弱.青紫泥中，SM2和DOX共存下的土壤微生物代谢多样性高于二者单一存在，且青紫泥中DOX浓度与土壤代谢活性和微生物群落代谢多样性呈显著正相关，而小粉土中无类似的现象，但SM2与DOX复合污染对土壤微生物代谢的影响总体源于DOX的作用.

Behavior and ecotoxicity of single and mixed antibiotics in soils: Degradation and changes in microbial community

This work studied the short-term degradation of antibiotics in a purple clay and a silt soil after individual and combined application of sulfadimidine (SM2) and doxycycline (DOX);the responses of soil microbial community metabolism to different antibiotics perturbation were also compared;Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and MicroRESP^TM technology were used herein.Results indicated that the degradation rates of both SM2 and DOX on the 3^rd and 7^th day in the silt soil were higher than that in the purple clay.Compared with that in single antibiotic pollution systems,co-existence of DOX and SM2 in combined antibiotics pollution system inhibited the short-term degradation of both antibiotic types in the two soil types;this inhibition was stronger in the silt soil.Both the single and mixed antibiotics in this work enhanced the metabolisms of soil microbial community with antibiotic exposure concentration from 10mg/kg to 20mg/kg,whereas the impacts of antibiotics decreased as the exposure time of the antibiotic increased.In the purple clay,the mixed antibiotic treatment showed significantly higher metabolic diversity of soil microbial community than all the single antibiotic treatments;its metabolic activity and diversity of soil microbial community correlated positively and significantly with the DOX concentration.However,similar phenomena were not seen in the silt soil.Meanwhile,the effect of mixed antibiotic on soil microbial community metabolism was mainly due to the function of DOX herein.