受污染水环境中抗生素和抗生素抗性基因的分布规律及影响因子研究

Many urban areas in China are facing heavier environmental pressures, since traditional contaminants have been interlaced with emerging ones. As the important drugs in modern medical system, antibiotics, which are overused, mismanaged, and lacking in specialized treatment technology, become a kind of emerging contaminants after being discharged, and then transporting and transforming in environments. The biggest concern about antibiotics is the emergence and spread of antibiotic resistant bacteria originally induced by antibiotics. Also antibiotic resistance genes (ARGs) held by the resistant bacteria are regarded as a new type of contaminants. In academia, by now there are multiple knowledge gaps in the environmental distribution, the occurrence and development mechanism, and the interaction between antibiotics and ARGs. The proposed project selects typical coastal areas of East China Sea, where highly urbanized and industrialized, as the research targets. We plan to use environmental monitoring technologies, molecular ecological tools, and mathematical and statistical methods to fulfill the following tasks: 1) investigate the distribution of antibiotics and ARGs from the pollution sources to the coastal environments, and identify the key physicochemical factors and microbiological factors that impact on antibiotics and ARGs; 2) elucidate the main sources of antibiotics, explore the interaction between antibiotics and ARGs, and propose the spread pathways and mechanism of ARGs in the target areas; and 3) evaluate the ecological and health risks of antibiotics and ARGs in the polluted coastal environments. We will reveal the distribution rules of antibiotics and ARGs in the human-interfered water environments, and the outputs of the project will provide scientific basis for the effective management of pollution sources.

我国城镇地区传统污染与新兴污染复合交织，面临严峻的环境压力。作为现代医疗重要药物的抗生素，因过度使用、管理失措和缺乏专门处理技术，排入环境后经迁移转化成为一类新兴污染物，诱发抗生素抗性菌的出现与蔓延，抗性菌携带的抗生素抗性基因（ARGs）也被视为一种新型污染物。目前抗生素与ARGs的环境分布规律、发生发展机制、二者相互关系尚存在诸多空白。本项目选择我国高度城市化和工业化的东部沿海区域作为研究对象，使用环境监测、分子生态技术及数理统计方法，将从污染源至近岸海域全面考察抗生素和ARGs的分布特征，识别影响抗生素和ARGs的重要理化因子和微生物因子；解析目标海域中抗生素主要来源，探究抗生素与ARGs的相互关系，提出ARGs的传播途径和机制；评估该受污染水环境中抗生素和ARGs的生态与健康风险。研究将揭示受人类活动影响的水环境中抗生素和抗性基因的分布规律，为有效开展污染源控制提供科学依据。

随着沿海地区工业化和城市化发展，我国近海面临严峻的环境压力，抗生素和抗生素抗性基因（ARGs）等新兴污染物的排放和累积又带来了潜在的生态与健康风险。项目选择我国东部沿海的杭州湾（HB）、象山湾（XB）和台州湾（TB）为研究区域，系统解析了从陆地污水处理厂（WWTPs）到近岸海域中的抗生素和ARGs分布特征，识别了影响二者的重要环境因子，并评估其生态与健康风险，为有效开展陆地污染源控制提供了科学依据。研究主要结论为：.(1) 针对各类样品，建立了高效的抗生素富集提取方法和UPLC-MS/MS分析方法以及ARGs的PCR和qPCR检测方法。.(2) 在HB区域，WWTPs排水中抗生素浓度排序为：制药废水>综合工业源废水>综合生活源排水；喹诺酮在处理流程的水相与泥相中均为主要抗生素。.(3) 近岸海水和沉积物中总抗生素浓度分别为30.8~2106.1 ng/L和2.2~99.9 ng/g，且在水相中呈距离衰减趋势；CLIN和ETM分别在水和沉积物中含量最高；COD、油类和重金属与抗生素的分布呈显著正相关关系。.(4) 6种抗生素在水相中具有明显生态风险，9种抗生素在沉积物中呈现低或中等慢性毒性；HB和TB水相抗生素风险较大，XB沉积物抗生素风险较大。.(5) 基于检出频次、浓度和生态风险3个约束条件，构建优先控制抗生素的筛选框架，并筛选出HB中优先监测和控制的抗生素种类。.(6) 污水处理厂排水中较高丰度的ARGs对近岸海域具有潜在风险。TB沉积物中总ARGs丰度显著高于HB与XB；sulI、tetW和dfrA13基因在三个海湾中占主导；重金属、营养盐和有机物的共同作用影响着ARGs分布。.(7) 多重耐药类ARGs在近岸海域的沉积物中占据主导地位；纳污区的ARGs主要来源于污水处理厂，部分浓度高、生态风险较高的抗生素显著影响了ARGs组成；噬菌体和质粒等MGEs在ARGs的水平转移过程中起到关键作用。