Abstract
The in-situ static box method was used to conduct a comparative experiment on sludge treatment wetlands (STWs). STW1 had ventilation structure, without reeds and STW2 had ventilation and was planted with reeds. The absolute abundance of sulfonamide, tetracycline and macrolide antibiotic resistance genes (ARGs) in the two STWs were analyzed, and the paper discussed pollution characteristics of typical antibiotic resistance genes in the two STWs. The results showed that three ARGs, sul1 (sulfonamides), tetC (tetracyclines), ermf (macrolides), were detected in STW1 and STW2. The concentration of arginine was sul1 > tetC > ermf. The concentration level of AGRS in STW1 and STW2 was lower in bottom layer than that of surface layer sludge. The removal efficiency of ARGs in the same system was tetC > sul1 > ermf, and the removal efficiency of surface sludge and bottom sludge in different systems was STW2 > STW1. Planting wetland plants in the STW can promote the removal of ARGs.
Highlights
As a new type of pollutant, antibiotic resistance genes (ARGs) is persistent in environmental media, and can be transferred and transmitted among different bacterial populations through gene level transfer [1]
Three kinds of ARGs were detected in STW1, STW2 surface sludge and bottom sludge, among the ARGs, sul1 showed the highest concentrations, followed
In the surface and bottom sludge of STW1 and STW2, the removal rate of tetracycline resistance gene was the highest, followed by sulfonamide resistance gene to macrolide resistance gene was the lowest. This is similar to Cristina et al's study on the removal of antagonistic genes in two vertical flow wetlands, which showed that the average removal rates of sul2 and ermB are 33-97% and 9-99% respectively [13]
Summary
As a new type of pollutant, antibiotic resistance genes (ARGs) is persistent in environmental media, and can be transferred and transmitted among different bacterial populations through gene level transfer [1]. The main sources and pathways of resistance genes in soil environment are shown in Fig.. The wastewater from medical treatment, industry, aquaculture and daily life is the main medium for the transmission of resistance genes in the environment. Some resistance genes enter the sewage treatment plant in the form of parent or metabolites and transfer to the soil environment with the way of sludge farming, and some are directly discharged into the environment. The removal of resistance genes in existing sludge treatment processes and sewage treatment technologies is limited, and the vast majority of resistance genes enter the soil environment through agricultural utilization, causing pollution to plants. A large number of resistance genes in the environment pose a threat to human health through enrichment and amplification of the food chain
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