College of Resources and Environment, Southwest University, Chongqing, 400716, PR China; School of Agriculture and Biotechnology, Shenzhen Campus of SunYat-sen University, Shenzhen, 518107, PR China.
College of Resources and Environment, Southwest University, Chongqing, 400716, PR China.
Water Res. 2024 Dec 1;267:122508. doi: 10.1016/j.watres.2024.122508. Epub 2024 Sep 24.
The vertical migration and leaching behavior of antibiotic resistance genes (ARGs) during rainfall in soils subjected to long-term fertilization remain largely unclear. In this study, ARGs in vertical profiles (0-60 cm) and leachates from three soils (acidic, neutral, and calcareous) in a long-term (13 years) field fertilization experiment were monitored by high-throughput quantitative PCR after each rainfall event throughout an entire year. The results showed that, compared with unfertilized soils, long-term manure fertilization mainly promoted the vertical migration and leaching of aminoglycoside, beta-lactam, and multidrug resistance genes in the soil profiles. As a result, the annual cumulative loads of ARGs in leachates from the three soils with long-term manure fertilization were significantly increased compared to the controls and were in the order of acidic soil > neutral soil > calcareous soil. SourceTracker analyses revealed that manured soil was the predominant source of the ARGs in the soil leachate samples. Pseudomonas, Anaeromyxobacter, IMCC26256, and MND1 were identified as the dominant potential hosts responsible for the vertical migration and leaching of ARGs in the three soils. PiecewiseSEM analysis further showed that long-term manure fertilization affected the vertical migration of ARGs during rainfall mainly by altering soil properties (i.e., pH, soil organic carbon, and sand). Our results suggest that the ARGs in soils with long-term manure fertilization are a significant potential source of ARG pollution in groundwater, and the measures should be taken to mitigate the vertical migration and leaching of ARGs during rainfall.
在长期施肥的土壤中，抗生素抗性基因（ARGs）在降雨期间的垂直迁移和淋溶行为仍很大程度上不清楚。在这项研究中，通过高通量定量 PCR 监测了经过 13 年田间施肥试验的三种土壤（酸性、中性和石灰性）的垂直剖面（0-60 cm）和淋出液中的 ARGs，每次降雨后全年进行监测。结果表明，与未施肥土壤相比，长期粪肥施肥主要促进了土壤剖面中氨基糖苷类、β-内酰胺类和多药抗性基因的垂直迁移和淋溶。因此，长期粪肥施肥的三种土壤中淋出液中 ARG 的年累积负荷明显高于对照，顺序为酸性土壤>中性土壤>石灰性土壤。SourceTracker 分析表明，粪肥土壤是土壤淋出液中 ARG 的主要来源。假单胞菌、厌氧杆菌、IMCC26256 和 MND1 被鉴定为三种土壤中 ARGs 垂直迁移和淋溶的主要潜在宿主。分段 SEM 分析进一步表明，长期粪肥施肥主要通过改变土壤性质（即 pH 值、土壤有机碳和砂）来影响降雨期间 ARGs 的垂直迁移。我们的研究结果表明，长期粪肥施肥土壤中的 ARGs 是地下水 ARG 污染的一个重要潜在来源，应采取措施减轻降雨期间 ARGs 的垂直迁移和淋溶。
