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This work aimed to investigate the possible effect of 2 quenchers commonly used in H 2 O 2 -based advanced oxidation technologies (AOTs), i.e. catalase and sodium sulphite (Na 2 SO 3), on the analytical signal of 3 detectors coupled to liquid chromatography (LC): tandem mass spectrometry (LC-MS/MS), fluorescence detection (LC-FD) and LC-diode array detection (LC-DAD). The observation of analytical interferences for a group of compounds when studying the removal by continuous mode UV/H 2 O 2 of 26 micropollutants (MPs) from a spiked surface water (SW), for which the residual H 2 O 2 in the samples was quenched by Na 2 SO 3 , triggered the need of understanding these effects and thus catalase was used as comparative quencher. From the 26 MPs having a wide range of polarity and p K a , those monitored after electrospray ionization (ESI) under positive ionization (PI) mode and presenting a p K a higher than 5.9 revealed a great signal suppression, but only when using Na 2 SO 3 as H 2 O 2 quencher. In this sense, we further explored this effect by selecting 2 MPs, metoprolol and diclofenac, which had respectively signal suppression and no interference in the LC-MS/MS response. These MPs were analysed before and after addition of H 2 O 2 and catalase or Na 2 SO 3 in reaction vials, using: (i) different detectors coupled to LC, namely LC-MS/MS with ESI under PI and negative ionization (NI) modes, LC-FD and LC-DAD; (ii) different environmental matrices (SW, drinking water, wastewater) and ultrapure water; and (iii) different magnitude levels (0.1–10 mg L−1). The results demonstrated a remarkable signal suppression in LC-MS/MS analyses under PI mode for those compounds with p K a higher than 5.9, confirming the interfering effect of H 2 O 2 /Na 2 SO 3. To the best of our knowledge, the analytical interference in the LC-MS/MS analysis, after adding Na 2 SO 3 to quench H 2 O 2 in AOTs experiments was never reported before and the results presented herein support the recommendation to use catalase instead of Na 2 SO 3 as quencher in AOTs studies. Unlabelled Image • Sodium sulphite is not recommended as quencher in AOTs when using LC-MS/MS. • Catalase should be used as quencher of H 2 O 2 , when analysing by LC-MS/MS. • Matrix matched analytical validated methods are always recommended. • Analytical method validation must consider all the experimental steps of AOTs. [ABSTRACT FROM AUTHOR]

Abstract The presence of organic micropollutants (MPs) in the aquatic environment is strongly related to their difficult elimination by conventional water and wastewater treatment processes. Therefore, alternative treatment technologies are required to overcome this problem. In this domain, constructed wetlands (CWs) have gained increasing attention in the last years, mainly due to the low-cost, simple operation/maintenance and environmental friendliness of these systems. However, studies on the application of CWs to remove MPs from freshwater aquaculture effluents are still scarce. In this work, planted (Phragmites australis) vertical subsurface flow CWs, at microcosm scale, were investigated for the removal of MPs found in non-spiked freshwater aquaculture effluents, namely atrazine, isoproturon, perfluorooctanesulfonic acid (PFOS), clarithromycin, erythromycin, fluoxetine, norfluoxetine, and 2-ethylhexyl-4-methoxycinnamate (EHMC). A wider multi-component set of 36 MPs was also studied by adding these MPs at 100 ng L−1 to the same matrix (alachlor, atrazine, chlorfenvinphos, isoproturon, PFOS, azithromycin, clarithromycin, erythromycin, diclofenac, methiocarb, acetamiprid, clothianidin, thiacloprid, thiamethoxam, EHMC, simazine, atorvastatin, bezafibrate, carbamazepine, cephalexin, ceftiofur, citalopram, clindamycin, clofibric acid, diphenhydramine, enrofloxacin, fluoxetine, ketoprofen, metoprolol, norfluoxetine, ofloxacin, propranolol, tramadol, trimethoprim, venlafaxine, and warfarin). High weekly removal efficiencies (>87%) were observed for all MPs in both non-spiked and spiked experiments, with the exception of EHMC (removal rates between 0 and 86%). These results emphasize the potential of CWs to remove MPs from freshwater aquaculture effluents, but also the need to enhance the performance of these systems for the elimination of some recalcitrant MPs, such as EHMC, which was found at high concentrations in the studied effluents. Graphical abstract Unlabelled Image Highlights • Constructed wetland microcosms studied for the removal of organic micropollutants. • Spiked (36 micropollutants) and non-spiked aquaculture effluents were investigated. • Most micropollutants found in effluents were removed to below the detection limit. • Weekly removal efficiencies were higher than 87% for most spiked micropollutants. • The UV filter EHMC was the only recalcitrant micropollutant. [ABSTRACT FROM AUTHOR]

The presence of organic pollutants in the aquatic environment, usually found at trace concentrations (i.e., between ng L −1 and μg L −1 or even lower, known as micropollutants), has been highlighted in recent decades as a worldwide environmental concern due to their difficult elimination by conventional water and wastewater treatment processes. The relevant information on constructed wetlands (CWs) and their application for the removal of a specific group of pollutants, 41 organic priority substances/classes of substances (PSs) and 8 certain other substances with environmental quality standards (EQS) listed in Directive 2013/39/EU as well as 17 contaminants of emerging concern (CECs) of the Watch List of Decision 2015/495/EU, is herein reviewed. Studies were found for 24 PSs and 2 other substances with EQS: octylphenol, nonylphenol, perfluorooctane sulfonic acid, di(2-ethylhexyl)phthalate, trichloromethane, dichloromethane, 1,2-dichloroethane, pentachlorobenzene, benzene, polychlorinated dibenzo-p-dioxins, naphthalene, fluoranthene, trifluralin, alachlor, isoproturon, diuron, tributyltin compounds, simazine, atrazine, chlorpyrifos (chlorpyrifos-ethyl), chlorfenvinphos, hexachlorobenzene, pentachlorophenol, endosulfan, dichlorodiphenyltrichloroethane (or DDT) and dieldrin. A few reports were also published for 8 CECs: imidacloprid, erythromycin, clarithromycin, azithromycin, diclofenac, estrone, 17-beta-estradiol and 17-alpha-ethinylestradiol. No references were found for the other 17 PSs, 6 certain other substances with EQS and 9 CECs listed in EU legislation. [ABSTRACT FROM AUTHOR]