Removal of typical sulfonamide resistance genes by ultraviolet/hydrogen peroxide advanced oxidation process in mariculture wastewater

Antibiotics are extensively used in the mariculture sector, leading to the emergence and dissemination of antibiotic resistance genes (ARGs) and posing a serious threat to public health. Therefore, it is urgent to remove and control of ARGs in the mariculture environment. In this study, in order to assess the efficiency and mechanism of ARGs removal, we employed the ultraviolet/hydrogen peroxide (UV/H2O2) advanced oxidation process (AOP) to treat mariculture wastewater containing prevalent sulfonamide resistance genes, namely sul1, sul2, and intl1. The results demonstrated that UV/H2O2 AOP effectively eliminated ARGs, achieving a significant reduction of 2.51–2.71 log for 16S rRNA, intl1, sul1, and sul2 genes after 10 min of treatment with a UV dose of 570 mJ·cm−2, 0.01 mol·L−1 H2O2, and pH 3. The removal of ARGs was influenced by the concentration of the oxidizing agent. Specifically, as the H2O2 concentration increased, the removal of ARGs initially increased and then decreased. Moreover, UV/H2O2 AOP exhibited different removal efficiencies for intracellular ARGs (iARGs) and extracellular ARGs (eARGs). The absolute abundance of iARGs gradually decreased, the eARGs were less impacted by the UV/H2O2 AOP treatment. Furthermore, the microbial community exhibited distinct sensitivities to UV/H2O2 AOP and UV treatment. Proteobacteria and Campylobacterota consistently appeared as dominant phyla, with Sulfurovum being the dominant genus. These findings shed light on the control of ARGs in mariculture wastewater and confirmed the promising prospects of UV/H2O2 AOP as an effective approach.