摘要

       大量的抗生素抗性基因 (ARG) 与处理过的残留城市废水固体一起排放，随后应用于土壤。这项工作的目的是确定经过处理的废水固体的模拟土地应用后 ARG 和 1 类整合子的衰减率。在两个独立的实验中，将来自两个全面处理厂的处理过的残留固体应用于三份土壤微观世界。实验 1 研究了 20、40 和 100 g kg-1 残留固体向沙质土壤的加载率，而实验 2 研究了 40 g kg-1 加载到粉质壤土的加载率。五个 ARG（erm(B)、sul1、tet(A)、tet(W) 和 tet(X)）、1 类整合子的整合酶 (intI1)、16S rRNA 基因、所有拟杆菌属的 16S rRNA 基因，和人类特异性拟杆菌属的 16S rRNA 基因。使用实时聚合酶链反应进行定量。在大多数微观世界中，ARG 和 intI1 数量下降，具有统计学显着性 (P < 0.05) 半衰期在 13 天（erm(B)，实验 1，100 g kg–1）和 81 天（intI1，实验 1，40 g）之间变化公斤-1）。这些动力学速率比先前报道的用于处理废水固体（例如厌氧消化）的单元操作要慢得多。这项研究表明，以减少 ARGs 排放为明确目标的市政污水处理设施的设计和运营应侧重于在处理设施内使用技术，而不是依赖于土地应用后的衰减。

       Substantial quantities of antibiotic resistance genes (ARGs) are discharged with treated residual municipal wastewater solids and subsequently applied to soil. The objective of this work was to determine the decay rates for ARGs and class 1 integrons following simulated land application of treated wastewater solids. Treated residual solids from two full-scale treatment plants were applied to sets of triplicate soil microcosms in two independent experiments. Experiment 1 investigated loading rates of 20, 40, and 100 g kg–1 of residual solids to a sandy soil, while experiment 2 investigated a loading rate of 40 g kg–1 to a silty-loamy soil. Five ARGs (erm(B), sul1, tet(A), tet(W), and tet(X)), the integrase of class 1 integrons (intI1), 16S rRNA genes, 16S rRNA genes of all Bacteroides spp., and 16S rRNA genes of human-specific Bacteroides spp. were quantified using real-time polymerase chain reaction. ARGs and intI1 quantities declined in most microcosms, with statistically significant (P < 0.05) half-lives varying between 13 d (erm(B), experiment 1, 100 g kg–1) and 81 d (intI1, experiment 1, 40 g kg–1). These kinetic rates were much slower than have been previously reported for unit operations used to treat wastewater solids (e.g., anaerobic digestion). This research suggests that the design and operation of municipal wastewater treatment facilities with the explicit goal of mitigating the release of ARGs should focus on using technologies within the treatment facility, rather than depending on attenuation subsequent to land application.

https://pubs.acs.org/doi/abs/10.1021/es501098g