摘要

       这项研究评估了多次排放处理后的废水对密西西比河上游抗生素抗性基因 (ARG) 的数量。 2012 年夏季，在 4 天的三个不同时期沿密西西比河收集了地表水和处理过的废水样本，并使用定量实时 PCR (qPCR) 枚举了几个 ARG 和相关目标。尽管废水流出物中 ARGs 的含量比河水高 75 到 831 倍，但密西西比河中 ARGs 的数量并没有随着下游距离的增加而增加。来自不相容组 A/C 的质粒在废水流出物中检测到的含量很低，但在河水中未检测到；在废水流出物或河流样本中均未检测到来自克隆载体的含有氨苄青霉素抗性基因 (bla) 的合成 DNA。一个简单的一维模型表明，废水排放对 ARG 水平影响较小的主要原因是与废水排放相比，密西西比河的流速较大。此外，该模型通常高估了密西西比河中的 ARG 水平，表明河流中发生了大量损失机制（例如，腐烂或沉积）。

       This study evaluated multiple discharges of treated wastewater on the quantities of antibiotic resistance genes (ARGs) in the Upper Mississippi River. Surface water and treated wastewater samples were collected along the Mississippi River during three different periods of 4 days during the summer of 2012, and quantitative real-time PCR (qPCR) was used to enumerate several ARGs and related targets. Even though the wastewater effluents contained 75- to 831-fold higher levels of ARGs than the river water, the quantities of ARGs in the Mississippi River did not increase with downstream distance. Plasmids from the incompatibility group A/C were detected at low levels in the wastewater effluents but not in the river water; synthetic DNA containing an ampicillin resistance gene (bla) from cloning vectors was not detected in either the wastewater effluent or river samples. A simple 1D model suggested that the primary reason for the small impact of the wastewater discharges on ARG levels was the large flow rate of the Mississippi River compared to that of the wastewater discharges. Furthermore, this model generally overpredicted the ARG levels in the Mississippi River, suggesting that substantial loss mechanisms (e.g., decay or deposition) were occurring in the river.

https://pubs.acs.org/doi/abs/10.1021/acs.est.5b02803