Antibiotic resistance genes in treated wastewater and in the receiving water bodies: A pan-European survey of urban settings

There is increasing public concern regarding the fate of antibiotic resistance genes (ARGs) during wastewater treatment, their persistence during the treatment process and their potential impacts on the receiving water bodies. In this study, we used quantitative PCR (qPCR) to determine the abundance of nine ARGs and a class 1 integron associated integrase gene in 16 wastewater treatment plant (WWTP) effluents from ten different European countries. In order to assess the impact on the receiving water bodies, gene abundances in the latter were also analysed.Six out of the nine ARGs analysed were detected in all effluent and river water samples. Among the quantified genes, intI1 and sul1 were the most abundant. Our results demonstrate that European WWTP contribute to the enrichment of the resistome in the receiving water bodies with the particular impact being dependent on the effluent load and local hydrological conditions. The ARGs concentrations in WWTP effluents were found to be inversely correlated to the number of implemented biological treatment steps, indicating a possible option for WWTP management.Furthermore, this study has identified blaOXA-58 as a possible resistance gene for future studies investigating the impact of WWTPs on their receiving water.COST ActionTekirdag Namık Kemal University-Corlu Faculty of Engineering3203301

Heterogeneous photocatalytic degradation, mineralization and detoxification of ampicillin under varying pH and incident photon flux conditions

<p>Most antibiotics have been demonstrated to be low biodegradable in biological treatment systems, thus advanced oxidation processes, particularly solar photocatalytic oxidation also known as a green process, have gained an essential attraction for their effective removal from effluents. However, so far there has been a very limited number of studies on ampicillin (AMP) removal that focused on one initial concentration of AMP and fixed photon energy. Therefore, this study was designed to investigate the effect of varying pH and incident photon fluxes on heterogeneous photocatalytic AMP removal at two AMP initial concentrations (50 and 100 mg L⁻¹) using 0.5 g L⁻¹ TiO₂ dose under UV-A (315–400 nm wavelengths) irradiation. Photocatalytic experiments were run in a vessel with 200-mL effective sample volume. Process efficiency was monitored by degradation (UV–vis, LC-MS/MS), mineralization (TOC), and acute toxicity to <i>Daphnia magna</i> during 24–48 h exposure times to evaluate possible toxic effect of oxidation by-products. Toxicity results and TOC removal (30–60 min) indicated simultaneous mineralization and degradation of both initial AMP concentrations. Lower ratio of TiO₂/AMP, as one of the key factors affecting the oxidation efficiency, promoted increasing formation of by-products that interacted with surface chemistry on TiO₂ nanoparticles leading to a process efficiency decrease at 100 mg L⁻¹ AMP initial concentration. When photon energy was increased, it enhanced the removal of AMP. A preliminary cost evaluation showed that a 3.62 mW cm⁻² energy flux was satisfying to obtain over 50% of TOC removal and a nearly complete detoxification of 50 mg L⁻¹ AMP.</p