Distribution of Sulfonamide Antibiotics and Resistance Genes and Their Correlation with Water Quality in Urban Rivers (Changchun City, China) in Autumn and Winter

With the extensive use of antibiotics, antibiotics, and antibiotic resistance genes (ARGs), contamination in the water environment is becoming severe in recent years. This study examined the distribution characteristics of sulfonamide antibiotics and resistance genes in the urban section of the Yitong River in autumn and winter. In addition, the correlation between them and water quality parameters was analyzed using Pearson correlation analysis. The surface water from the Yitong River was sampled in September and November for this experiment. The results of 32 samples showed that seven sulfonamides were detected in the surface water and sediments of this reach, and the concentrations were generally at the levels of ng/L and ng/g. The total concentration range was 11–161 ng/L and ND-85.7 ng/g. The concentrations of different antibiotics were similar in autumn and winter, and the concentration of sulfamethoxazole (SMX) was higher than that of other antibiotics. The results of the Risk Quotients (RQs) showed that SMX and sulfadiazine (SDZ) had moderate acute risk to the corresponding sensitive species in river water, sulfapyridine (SPD) and sulfisoxazole (SIZ) had low acute risk, while the rest had no risk. The total bacterial abundance in surface water and sediment was in the range of 10 4 –10 5 copies/mL and 10 8 –10 11 copies/g, respectively. The detection rates of three sulfonamide resistance genes were 100%; the relative abundance was in the range of 10 −3 –10 −1 copies/16S rRNA, and sul1 was the primary resistance gene. The results of correlation analysis showed that there was a significant positive correlation between sulfamethazine (SMZ), sulfathiazole (STZ), and SIZ and water quality indexes such as total nitrogen (TN) and total phosphorus (TP), ammonia nitrogen (NH 3 -N) and chlorophyll a (Chl-a). The river‘s change of water quality environment could significantly affect the antibiotics’ spatial distribution characteristics and content. The higher the level of nutrients, the higher the concentration of antibiotics. The abundance of sulfa resistance genes was positively correlated with the concentration of sulfa antibiotics. Frequent human activities can increase antibiotic concentration, leading to the production of more resistance genes induced by antibiotics, but the main reason for the formation of resistance genes was not apparent. Therefore, exploring the occurrence and pollution characteristics of antibiotics and ARGs in the environment of the Yitong River Basin in Changchun City and analyzing their sources, transmission, and ecological risks in the environment provided an essential scientific basis for pollution prevention and ecological protection of urban rivers in northern China.