The whole world is currently facing a serious health threat resulting from the multi-environmental spreading of antibiotic resistance genes (ARGs), which is a new type of high-profile pollutant. Especially in highly urbanized regions, human activities produce pollution and discharge into the water environment and atmosphere, leading to ARGs pollution. These ARGs may infiltrate into soil and leach into groundwater caused by hydrodynamic process of rainfall. However, the dynamic behavior of ARGs in soil during or after the rain was still not revealed, due to multi-factors and the complex biochemical process. The objectives of this study included 16S rRNA gene, intI1 gene and 4 ARGs, and it was aimed to characterize the vertical transport of targeted ARGs (sul1, tetA, tetM, tetQ) following different rainfall intensity. Based on the soil column experiments, the correlation between ARGs and rainfall intensities was discussed, suggesting that simulated rainfall increase the abundance of ARGs in the soil. Moreover, the vertical profiles of ARGs’ abundance in the soil changed significantly after the simulated rainfall, and there was a very high possibility that ARGs could migrated to deep soil. These results described the vertical migration of ARG in soil under rainfall conditions, which can provide useful information for the prevention and control of the ARG migration towards deep soil and groundwater.
As an emerging contaminant in the environment, antibiotic resistance genes (ARGs) can harbor in bacteria, especially pathogenic bacteria, which have raised the concerns to the environment and human health (Cui, 2018; Ezzariai, 2018; Berendonk, 2015; Pruden, 2006). One of the important transmission pathways for ARGs in the environment occurs at the air-soil interface and spreads towards subsurface soil (Christou, 2017; Frey, 2015; Szekeres, 2018). Environmental factors such as precipitation and rainfall intensity play a crucial role in ARGs’ proliferation during this vertical transmission (Chen, 2017; Li, 2018). In rainy seasons, ARGs can be washed downward to soil layers affected by the rainfall, and migrate into the vadose soil (Sun, 2019), which would result in the enrichment of ARGs in the soil and increase the environmental risk (Qiu, 2021).
