Liang Luyi, Qin Litang, Liu Yongan, Mo Lingyun, Dai Junfeng, Wang Dunqiu
College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China.
Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541006, China.
Toxics. 2024 Jul 19;12(7):521. doi: 10.3390/toxics12070521.
Antibiotics are considered as persistent emerging contaminants. The phenomenon of mixed exposure to the environment is a common occurrence causing serious harm to human health and the environment. Therefore, we employed enrofloxacin (ENR), chlortetracycline (CTC), methotrexate (TMP), chloramphenicol (CMP), and erythromycin (ETM) in this study. Nine treatments were designed using the uniform design concentration ratio (UDCR) method to systematically determine the toxicity of individual contaminants and their mixtures on sp.-Q67 through the time-dependent microplate toxicity assay. The combinatorial index (CI) method and the dose reduction index (DRI) were used to analyze the toxic interactions of the mixtures and the magnitude of the contribution of each component to the toxic interactions. The results showed that the toxicities of ENR, CTC, TMR, CMP, and ETM and their mixtures were time-dependent, with toxic effects being enhanced except when exposure time was prolonged. The types of toxic interactions in the ENR-CTC-TMR-CMP-ETM mixtures were found to be correlated with the proportion of each component's concentration, where the proportion of the components exerted the most significant influence. Through DRI extrapolation, it was determined that the primary components of the mixture exhibited a pronounced dependency on time. Specifically, at the 4 h mark, TMP emerged as the predominant component, gradually giving way to ENR as time advanced. Upon analyzing the frequency of mixture interactions under specified effects, the additive effect appeared most frequently (66.6%), while the antagonist effect appeared the least frequently (15.9%) among the nine rays.
抗生素被视为持久性新兴污染物。环境混合暴露现象屡见不鲜，对人类健康和环境造成严重危害。因此，本研究采用了恩诺沙星（ENR）、金霉素（CTC）、甲氧苄啶（TMP）、氯霉素（CMP）和红霉素（ETM）。采用均匀设计浓度比（UDCR）方法设计了九种处理，通过时间依赖性微孔板毒性试验系统地测定单一污染物及其混合物对sp.-Q67的毒性。采用组合指数（CI）法和剂量降低指数（DRI）分析混合物的毒性相互作用以及各组分对毒性相互作用贡献的大小。结果表明，ENR、CTC、TMR、CMP和ETM及其混合物的毒性具有时间依赖性，除暴露时间延长外，毒性作用均增强。发现ENR-CTC-TMR-CMP-ETM混合物中的毒性相互作用类型与各组分浓度比例相关，其中各组分比例影响最为显著。通过DRI外推法确定，混合物的主要成分对时间有明显的依赖性。具体而言，在4小时时，TMP成为主要成分，随着时间的推移逐渐被ENR取代。在分析特定效应下混合物相互作用的频率时，九种情况下加和效应出现的频率最高（66.6%），而拮抗效应出现的频率最低（15.9%）。
