LC-QTOF MS screening of more than 1,000 licit and illicit drugs and their metabolites in wastewater and surface waters from the area of Bogotá, Colombia

A large screening of around 1,000 emerging contaminants, focused on licit and illicit drugs and their metabolites, has been made in urban wastewaters (both influent and effluent) and surface waters from the area of Bogotá, Colombia. After a simple generic solid-phase extraction (SPE) step with Oasis hydrophilic-lipophilic balanced (HLB) cartridges, analyses were made by ultra high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) under MSE mode (sequential acquisition of mass spectra at low energy (LE) and high collision energy (HE)). Accurate mass measurements and the information provided by MSE on the presence of the (de)protonated molecule and fragment ions allowed the reliable identification of the compounds detected, even without reference standards being available in some cases (tentative identification). The compounds most frequently found were acetaminophen/paracetamol, carbamazepine and its dihydro-dihydroxylated metabolite, clarithromycin, diclofenac, ibuprofen, gemfibrozil, lincomycin, losartan, valsartan, the two metabolites of metamizole (4-acetamido-antipyrine and 4-formylamino-antipyrine), sucralose, and cocaine and its main metabolite benzoylecgonine. Caffeine, the sweetener saccharin, and two hydroxylated metabolites of losartan were tentatively identified in almost all samples analyzed. Pharmaceutical lidocaine was tentatively identified and subsequently confirmed with reference standard. For the first time, a general overview of the occurrence of drugs and their metabolites in the aquatic environment of Colombia has been reported. In the near future, target methodologies, typically based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), will need to be set up for accurate and sensitive quantification of the contaminants selected on the basis on the information provided in the present paper

Sonochemical degradation of antibiotics from representative classes-Considerations on structural effects, initial transformation products, antimicrobial activity and matrix

In this work, the sonochemical treatment (at 354 kHz and 88 W L-120 ) of six relevant antibiotics belonging to fluoroquinolones (ciprofloxacin and norfloxacin), penicillins (oxacillin and cloxacillin) and cephalosporins (cephalexin and cephadroxyl) classes was evaluated. Firstly, the ability of the process to eliminate them was tested, showing that sonodegradation of these antibiotics is strongly chemical structure25 dependent. Thus, correlations among initial degradation rate of pollutants (Rd), solubility in water (Sw), water-octanol partition coefficient (Log P) and topological polar surface area (TPSA) were tested. Rd exhibited a good correlation with Log P (i.e., the hydrophobicity degree of antibiotics). The considered penicillins had the fastest elimination and from the constitutional analysis using Lemke method was clear that the functional groups arrangement on these antibiotics made them highly hydrophobics. The penicillins were degraded closer at cavitation bubble than the fluoroquinolones or cephalosporins. The investigation of degradation products showed that sonogenerated hydroxyl radical primary attacked the β-lactam ring of cloxacillin and cephalexin, whereas on norfloxacin induced a decarboxylation. On the other hand, the evolution of antimicrobial activity was also followed. It was evidenced the process capacity to remove antimicrobial activity from treated solutions, which was associated to the transformations of functional groups on antibiotics with important role for interaction with bacteria. Additionally, degradation of antibiotics having the highest (the most hydrophobic, i.e., cloxacillin) and lowest (the most hydrophilic, i.e., cephadroxyl) Rd, was performed in synthetic matrices (hospital wastewater and seawater). Ultrasound degraded both antibiotics; for cloxacillin in such waters higher eliminations than in distilled water were observed (probably due to a salting-out effect exerted by matrix components). Meanwhile, for cephadroxyl a moderate inhibition of degradation in hospital wastewater and seawater respect to distilled water was found, this was related to competition by hydroxyl radical of the other substances in the matrices. These results show the quite selectivity of high frequency ultrasound to eliminate antibiotics form different classes even in complex matrices

Degradation of seventeen contaminants of emerging concern in municipal wastewater effluents by sonochemical advanced oxidation processes

The simultaneous degradation of seventeen emerging concern pollutants in effluent from the municipal wastewater treatment plant (MWTP) of Bogotá-Colombia was studied using high frequency ultrasound (375 kHz). The considered compounds in the effluent corresponded to pharmaceuticals (diclofenac, carbamazepine, venlafaxine, ciprofloxacin, norfloxacin, valsartan, losartan, irbesartan, sulfamethoxazole, clarithromycin, azithromycin, erythromycin, metronidazole, trimethoprim and the high potentiality of the sono-photo-Fenton/oxalic acid system for the pollutants elimination in real-world wastewater matrices. clindamycin); cocaine and its major metabolite benzoylecgonine. Due to limitation of the MWTP for the pollutants elimination, ultrasound was applied to remove these compounds. Interestingly, ultrasonic physical action led to releasing of ciprofloxacin, norfloxacin, diclofenac and sulfamethoxazole from suspended solids, whereas the chemical effects induced degradation of the rest of compounds. For the latter ones, an interesting correlation between the sonodegradation and arithmetic multiplication between hydrophobicity and concentration of pollutants was established. Afterwards, the sonochemical process was complemented with ferrous ions (sono-Fenton), ferrous ions plus light (sono-photo-Fenton) or ferrous ions plus light in presence of oxalic acid (sono-photo-Fenton/oxalic acid). Additionally, to clarify fundamental aspects of the different systems, individual treatments in distilled water of a model pollutant (valsartan) were performed. The complemented processes significantly enhanced all compounds degradation, following the order: sono-photo-Fenton/oxalic acid > sono-photo-Fenton ~ sono-Fenton > sonochemistry. The Fe2+ addition improved the pollutants elimination by generation of more hydroxyl radicals in the solution bulk. Meanwhile, oxalic acid avoided Fe3+ precipitation favoring the iron catalytic cycle. Thus, the work demonstrate

Optimization and application of a continuous flow photo-electro-Fenton system for the removal of pharmaceutical active compounds detected in irrigation water of Bogotá – Savanna (Colombia) Crops

In this study, a continuous flow photo-electro-Fenton (PEF) system was evaluated for its ability to remove pharmaceutically active compounds (PhACs) from irrigation water used in Bogotá-savanna crops. The PEF system consisted of dimensionally stable anode and graphite diffusion gas cathode, which were irradiated with LEDs. Firstly, the system was optimized using response surface methodology (RSM) in ultrapure water. The most favorable conditions for efficient generation of oxidants (the response variable) were found to be a flow rate of 210 mL/min, a current density of 15 mA/cm2, and an electrolyte concentration of 0.1 mol NaCl/L. Subsequently, model compounds of PhACs, including losartan (LOS), sulfamethoxazole (SMX), and diclofenac (DCF), were eliminated after only 10 min of treatment under the previously established conditions. After demonstrating the potential of the PEF system to eliminate PhACs, the system was applied to real irrigation water to evaluate the degradation of seven PhACs, namely carbamazepine (CBZ), sulfamethoxazole (SMX), ciprofloxacin (CIP), clarithromycin (CLR), diclofenac (DCF), valsartan (VAL), and trimethoprim (TMP). The results showed that after 30 min of treatment with the PEF system, the concentration of these compounds was drastically reduced remaining undetected. This demonstrates the high potential of the PEF system to reduce the presence of PhACs in irrigation water and associated environmental and food health risks

Simultaneous E-coli inactivation and NOM degradation in river water via photo-Fenton process at natural pH in solar CPC reactor. A new way for enhancing solar disinfection of natural water

Bacteria inactivation and natural organic matter oxidation in river water was simultaneously conducted via photo-Fenton reaction at "natural" pH (similar to 6.5) containing 0.6 mg L-1 of Fe3+ and 10 mg L-1 of H2O2. The experiments were carried out by using a solar compound parabolic collector on river water previously filtered by a slow sand filtration system and voluntarily spiked with Escherichia coli. Fifty five percent of 5.3 mg L-1 of dissolved organic carbon was mineralized whereas total disinfection was observed without re-growth after 24 h in the dark. (C) 2009 Elsevier Ltd. All rights reserved

Significant decrease of THMs generated during chlorination of river water by previous photo-Fenton treatment at near neutral pH

An important issue in chlorine drinking water disinfection is the generation from natural organic matter (NOM) of disinfection by-products (DBPs), especially trihalomethanes (THMs). The THMs generation can be limited by reducing the levels of NOM prior to the chlorination step. Herein, photo-Fenton system under solar simulator degraded humic acid solutions (as NOM model compounds), as well as NOM contained in river water (Pance River, Cali-Colombia), and dramatically reduced THMs formation during the subsequent chlorination step. In both cases the initial pH of treated water was near to 7.In no pre-treated river water 100-160 mu g/L of THMs are formed during chlorination while values of 20-60 mu g/L were reached in water previously treated for 4 h by neutral photo-Fenton under solar simulator. The decrease in the generated THMs/total organic carbon ratio suggests that mainly the NOM fraction sensitive to THMs formation was photo-degraded. Therefore, the neutral photo-Fenton reagent could be implemented as a technological option for NOM removal for limiting THMs formation during a subsequent chlorination step. (C) 2011 Elsevier B.V. All rights reserved

Photo-electro-Fenton process applied to the degradation of valsartan: Effect of parameters, identification of degradation routes and mineralization in combination with a biological system

In this work, the oxidation of the antihypertensive drug valsartan by the Electro-Fenton (EF) and photo-electro-Fenton (PEF) processes was studied using a Ti/IrO2 doped with SnO2 as anode, and a carbon felt air diffusion electrode as cathode. Initially, the influence of variables such as supporting electrolyte type, current density, and pH on EF and/or PEF processes was evaluated. The processes were carried out in batch mode, in an open and undivided cell of 200 cm3. The efficiency of the systems was evaluated in terms of the removal of the initial contaminant and rate of mineralization. When NaCl was used as a supporting electrolyte at pH 3.0 and current density 3.46 mA/cm2 adding 3.6 × 10−5 mol/L of Fe2+, total valsartan (20 mg/L) degradation was observed after 45 min. After 120 min, even if total removal of valsartan was reached, only 25% of mineralization was obtained. Thus, valsartan degradation tests at near neutral pH in presence of oxalic acid (4.6 × 10−5 mol/L) lead to comparable results with those obtained at pH 3.0. Primary aromatic intermediates were identified by high resolution mass spectrometry (HRMS) using hybrid quadrupole- time-of-flight (QTOF) MS, from which an initial degradation pathway was proposed. At the end of the PEF system, several aliphatic acids were accumulated and observed, which were effectively removed in a subsequent aerobic biological system. The results demonstrate the feasibility of PEF and biological coupling process to completely mineralize emerging pharmaceutical pollutants, such as valsartan, at natural pH

The detrimental influence of bacteria (E. coli, Shigella and Salmonella) on the degradation of organic compounds (and vice versa) in TiO2 photocatalysis and near-neutral photo-Fenton processes under simulated solar light

TiO2 photocatalytic and near-neutral photo-Fenton processes were tested under simulated solar light to degrade two models of natural organic matter - resorcinol (R) (which should interact strongly with TiO2 surfaces) and hydroquinone (H) - separately or in the presence of bacteria. Under similar oxidative conditions, inactivation of Escherichia coli, Shigella sonnei and Salmonella typhimurium was carried out in the absence and in the presence of 10 mg L-1 of R and H. The 100% abatement of R and H by using a TiO2 photocatalytic process in the absence of bacteria was observed in 90 min for R and in 120 min for H, while in the presence of microorganisms abatement was only of 55% and 35% for R and H, respectively. Photo-Fenton reagent at pH 5.0 completely removed R and H in 40 min, whereas in the presence of microorganisms their degradation was of 60% to 80%. On the other hand, 2 h of TiO2 photocatalytic process inactivated S. typhimurium and E. coli cells in three and six orders of magnitude, respectively, while S. sonnei was completely inactivated in 10 min. In the presence of R or H, the bacterial inactivation via TiO2 photocatalysis was significantly decreased. With photo-Fenton reagent at pH 5 all the microorganisms tested were completely inactivated in 40 min of simulated solar light irradiation in the absence of organics. When R and H were present, bacterial photo-Fenton inactivation was less affected. The obtained results suggest that in both TiO2 and iron photo-assisted processes, there is competition between organic substances and bacteria simultaneously present for generated reactive oxygen species (ROS). This competition is most important in heterogeneous systems, mainly when there are strong organic-TiO2 surface interactions, as in the resorcinol case, suggesting that bacteria-TiO 2 interactions could play a key role in photocatalytic cell inactivation processes.Fil: Moncayo Lasso, Alejandro. Universidad del Valle; ColombiaFil: Mora Arismendi, Luis Enrique. Universidad del Valle; ColombiaFil: Rengifo Herrera, Julian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas ; ArgentinaFil: Sanabria, Janeth. Universidad del Valle; ColombiaFil: Benítez, Norberto. Universidad del Valle; ColombiaFil: Pulgarin, Cesar. Ecole Polytechnique Federale de Lausanne; Suiz

Comparative degradation of two highly consumed antihypertensives in water by sonochemical process. Determination of the reaction zone, primary degradation products and theoretical calculations on the oxidative process

This work compares the sonochemical degradation of losartan and valsartan (antihypertensives) in water. Initially, the suitable operational conditions of ultrasonic power density and frequency were established. Under such conditions, losartan was eliminated in a higher percentage than valsartan, which was associated to differences in their hydrophobicities. Additionally, degradations in presence of isopropanol and ferrous ions confirmed that losartan was closer to cavitation bubble than valsartan. The structures of primary products indicated that sonogenerated hydroxyl radical attacked biphenyl tetrazole moiety (common nucleus of both pharmaceuticals). Then, theoretical calculations were applied to the products to estimate the toxicity, degree of oxidation and probable routes of aerobic biodegradation suggesting a beneficial action of sonodegradation. Finally, the sonochemical degradation of the antihypertensives was carried out in two simulated complex matrices (i.e., seawater and hospital wastewater) and an actual wastewater. Interestingly, the losartan and valsartan eliminations in such waters were similar to the observed in distilled water. This fact indicates the high potentiality of ultrasound to degrade losartan or valsartan in waters containing other substances, even at higher concentrations than these pollutants