江苏省代表性水源地抗生素及抗性基因赋存现状

抗生素和抗生素抗性基因（antibiotic resistance genes，ARGs）是环境中重要的新兴污染物，为探明江苏省代表性水源地多种环境介质中抗生素和ARGs的污染水平及影响因素，于2018年12月和2019年6月采集苏北、苏中和苏南的5处代表性集中式饮用水水源地取水口处水体、表层沉积物和石相附着生物膜样品，对3种介质中10种代表性抗生素浓度、1类整合子酶基因intl1和7种代表性ARGs的绝对丰度进行检测分析.结果表明，5处水源地中目标抗生素和ARGs处于较低赋存水平.磺胺类抗生素在水体、表层沉积物和附着生物膜中的赋存量分别为NF（未检出）~37.4 ng·L^-1，NF~47.3 ng·g^-1和NF~3759.1 ng·g^-1.喹诺酮类抗生素在3种介质中的浓度和含量分别为NF~5.3 ng·L^-1、0.4~32.5 ng·g^-1和NF~4220.9 ng·g^-1.目的ARGs中，sul1、sul2、tetW和tetQ的检出率为100%，其中磺胺类抗生素ARGs，即sul1和sul2基因丰度最高.表层沉积物和附着生物膜中的ARGs丰度相当，高于水体中ARGs的丰度.网络分析结果表明，所属拟杆菌门、变形菌门、厚壁菌门、疣微菌门和放线菌门的细菌最有可能成为代表性水源地中ARGs的潜在宿主，在ARGs的扩散和转移过程中起重要作用.研究结果对于江苏省集中式饮用水源地水环境质量状况评估和水质安全保障具有一定的科学指导意义.

Occurrence of Antibiotics and Antibiotic Resistance Genes in Representative Drinking Water Resources in Jiangsu Province

Emerging contaminants including antibiotics and antibiotic resistance genes (ARGs) have been frequently detected in drinking water resources. In this study, the occurrence of antibiotics and ARGs in various environmental matrices in representative drinking water sources in Jiangsu Province and their influencing factors were explored. Five representative drinking water sources in northern, central, and southern Jiangsu were selected. Water, surface sediment, and epilithic biofilm samples were harvested near the water intakes of each water resource in December 2018 and June 2019. The concentrations and abundances of ten antibiotics, one integrase gene intl1, and seven common ARGs were measured. The results suggest that the concentrations of the target antibiotics and ARGs are relatively low compared to previously reported data in China and elsewhere in the world. The target antibiotics were detected in all of the water sources. The concentrations of sulfonamides in the water, surface sediment, and epilithic biofilm ranged from not found (NF) to 37.4 ng·L^-1, NF to 47.3 ng·g^-1, and NF to 3759.1 ng·g^-1, respectively; the concentrations of quinolones in three matrices were NF-5.3 ng·L^-1, 0.4-32.5 ng·g^-1, and NF-4220.9 ng·g^-1, respectively. The detection rates of the ARGs including sul 1, sul2, tetW, and tetQ were 100%, among which the sulfonamides sul1 and sul2 showed the highest abundance. The absolute abundances of sul1 in the three matrices were 2.48×10⁶ copies·L^-1, 3.54×10⁷ copies·g^-1, and 1.44×10⁹ copies·g^-1, respectively. The abundances of ARGs in the sediments and epilithic biofilms were comparable, and were much higher than in the water body. The phyla Bacteroidetes, Proteobacteris, Firmicutes, Verrucobacteria, and Actinomycetes have proven potential hosts for ARGs and might play an important role in the transmission and diffusion of resistance genes. This study offers baseline information on the presence of antibiotics and ARGs in the drinking water sources of Jiangsu Province, providing a significant theoretical basis for ARGs pollution control and safety guidelines for drinking water resources.