摘要

       一些国家的城市河流受到严重污染，水变得又黑又臭。然而，只有少数研究报告了在经过和未经修复的城市河流中出现黑臭水体的抗生素及其相应的抗生素抗性基因（ARGs）。本研究对华南广州6条城市河流的水体和沉积物中的9种抗生素（磺胺类、四环素类、喹诺酮类和大环内酯类）及其相应的ARGs进行了分析，研究了它们的空间分布和水体修复的影响。个别抗生素在地表水和沉积物中的浓度分别从 ND（不可检测）到 2702ng/L 和 ND 到 449μg/kg。诺氟沙星的平均浓度最高，其次是环丙沙星。喹诺酮抗性基因 qnrA（~103 ARGs/16S rRNA）的相对丰度最高，其次是四环素抗性基因 tetC（~10-2 ARGs/16S rRNA）。不同河流沉积物中抗生素和ARGs呈现出明显的空间分布，从上游到下游变化较大。一般而言，受工业和生活污水影响的城市河流中含有黑臭水的城市河流中抗生素和四环素抗性基因（tetA、tetC 和 tetM）的水平高于修复后的城市河流中的抗生素和四环素抗性基因（tetA、tetC 和 tetM）。仅在 tetA（或 tetC）的相对丰度与某些抗生素（例如，环丙沙星和诺氟沙星）的浓度之间观察到显着的正相关。 TetA 还与沉积物中 Ni、Cr 和 As 的浓度呈显着正相关。该研究发现，通过疏浚修复城市河流可能会降低沉积物中的抗生素水平，但某些 ARG（例如 tetB、qnrA）的相对丰度可能仍然存在。

       Urban rivers in some countries have been heavily polluted and the water became black and odor. Nevertheless, only few studies reported the occurrence of antibiotics and their corresponding antibiotic resistant genes (ARGs) in urban rivers with black-odor water with and without remediation. In this study, nine antibiotics (belonging to sulfonamides, tetracyclines, quinolones, and macrolides) and their corresponding ARGs in water and sediments of six urban rivers in Guangzhou, South China were analyzed to investigate their spatial distribution and the influence of water remediation. The concentrations of individual antibiotics varied from ND (not detectable) to 2702 ng/L and ND to 449 μg/kg in surface water and sediments, respectively. Norfloxacin displayed the highest average concentrations, followed by ciprofloxacin. The relative abundance of quinolone-resistance gene qnrA (~103 ARGs/16S rRNA) was the highest, followed by tetracyclines-resistance genes tetC (~10−2 ARGs/16S rRNA). The antibiotics and ARGs in sediments from various rivers exhibited distinct spatial distribution with large variation from upstream to downstream. Generally, levels of antibiotics and tetracyclines-resistance genes (tetA, tetC and tetM) in urban rivers with black-odor water (affected by industrial and domestic sewage) were higher than those in remediated urban rivers. Significant positive correlations were observed only between the relative abundances of tetA (or tetC) with the concentrations of some antibiotics (e.g., ciprofloxacin and norfloxacin). TetA was also significantly positively correlated with the concentrations of Ni, Cr, and As in sediments. This study found that urban rivers remediated with dredging might lower antibiotic levels in sediment, but high relative abundance of certain ARGs (e.g., tetB, qnrA) may still exist.

https://www.sciencedirect.com/science/article/abs/pii/S0048969719311568