Browsing by Author "Maia, Alexandra S."
Now showing 1 - 10 of 25
Results Per Page
Sort Options
- Aerobic granular sludge sequencing batch reactor performance under fluorinated pharmaceuticals shock loadingsPublication . Moreira, Irina S.; Amorim, Catarina L.; Ribeiro, Ana R.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Calheiros, Cristina S. C.; Rangel, António O. S. S.; Loosdrecht, Mark C. M.; Tiritan, Maria E.; Castro, Paula M. L.The widespread usage of pharmaceuticals is of increasing concern. Aerobic granular sludge sequencing batch reactors (AGS-SBR) constitute a promising technology for the treatment of wastewaters, however how the removal of carbon and nutrients can be affected by such micropollutants is largely unknown. This study evaluates the impact of different fluorinated drugs (ofloxacin, norfloxacin, ciprofloxacin and fluoxetine) on the performance of an AGS-SBR. During 468 days, a sequence of intermittent, alternating and/or continuous shock loads of pharmaceuticals were apllied to an AGS-SBR and the effects on the main biological processes were evaluated. Here we report on the effect of fluoroquinolones on reactor performnce. The organic removal, measured by COD, was not markedly affected by pharmaceuticals shock loads. Ammonium and nitrite were practically not detected in the bioreactor effluent indicating that the presence of the pharmaceuticals did not inhibit nitrification, whereas accumulation of nitrate in the effluent was observed, indicating that denitrification was affected. Phosphate removal was affected to some extent. There was no evidence of biodegradation whereas adsorption of the target pharmaceuticals to the AGS was observed, which were gradually released into the medium after withdrawal from the inlet stream.
- Aerobic granules in a sequencing batch bioreactor under fluoroquinolone shock loadingsPublication . Amorim, Catarina L.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Tiritan, Maria E.; Castro, Paula M. L.The growing occurrence of human and veterinary pharmaceuticals in the environment is causing increasing concern. Fluoroquinolones (FQs) are broad-spectrum antibiotics that play an important role in the treatment of serious bacterial infections. Antibiotics can reach wastewater treatment plants (WWTP) from different routes. Domestic effluents are considered the major contributor but effluents from pharmaceutical industries and hospitals are also of great concern. Granular sequencing batch reactors (SBR) constitute a novel biofilm technology for wastewater treatment extremely promising for the treatment of effluents containing toxic compounds. Aerobic granular sludge has several advantages over activated sludge, such as excellent settling properties, high biomass retention, ability to deal with high organic loading rates and to perform simultaneously diverse biological processes, such as Chemical Oxygen Demand (COD), N and P removal. This study focused on the effect of intermittent and alternating feeding of different FQs, namely Ofloxacin (OFL), Norfloxacin (NOR) and Ciprofloxacin (CPF), on bioreactor performance and diversity of the microbial population. Activated sludge from a municipal WWTP was used as the inoculum for the start-up of the SBR. The aerobic granules grew under aerobic conditions and after ca. 3 months of reactor operation stable granules were observed. The FQs affected the granular sludge in terms of morphology, causing a decrease in granule size. The granules started to disintegrate and an increase in the levels of solids in the effluent after exposure to FQs occurred due to wash-out of unstable granules, concomitant with a decrease in the SBR bed volume. The effect of the target fluorinated pharmaceuticals on the main biological processes occurring in the granular sludge SBR, such as nitrification and phosphate removal, was evaluated. Ammonium and nitrite were practically not detected in the treated effluent (maximum concentration of 0.03 and 0.01 mM for NH4+-N and NO2--N, respectively) indicating that neither ammonia oxidizing bacteria (AOB) nor nitrite oxidizing bacteria (NOB) were inhibited by the presence of the FQs, whereas phosphate removal was affected. The phosphate released into the bulk liquid by the phosphate accumulating organisms (PAO) during the anaerobic feeding period was not completely removed and the levels of phosphate in the bioreactor effluent increased. The organic removal, measured by COD, was not markedly affected by FQ shock loads. Changes in the bacterial community from aerobic granules related to FQs shock loadings were examined using denaturing gradient electrophoresis (DGGE) of 16S rRNA. The clustering analysis suggested that samples clustered according to the temporal factor. The gradual succession observed in the bacterial assemblage composition was related with the exposure to FQs. Also, the microbial population present in the aerobic granules was also investigated by culture-dependent methods. Several bacterial isolates belonging to α- and ɣ-branch of the Proteobacteria phylum were retrieved from the granules. After ca. 2 months without FQs exposure, the SBR bed volume was recovered and the solid content at the bioreactor effluent returned to normal levels.
- Anthropogenic pressure in a Portuguese river: endocrine-disrupting compounds, trace elements and nutrientsPublication . Ribeiro, Cláudia M. R.; Maia, Alexandra S.; Ribeiro, Ana R.; Couto, Cristina; Almeida, Agostinho A.; Santos, Mariana; Tiritan, Maria E.Natural organic compounds such as phytoestrogens and phytosterols found in various plants, as well as mycotoxins produced by fungi, can be found in aquatic environments. The aim of this study was to investigate the occurrence of three different classes of natural estrogenic compounds, i.e., phytoestrogens, phytosterols and mycotoxins, in estuarine water samples from the Ave River estuary. For that, water samples were collected at five sampling points distributed along the estuary at low tide, during 1 year, processed by solid-phase extraction (SPE) and analyzed by gas chromatography coupled to mass spectrometry (GC–MS). To correlate the presence of phytoestrogens and phytosterols in the estuarine water, local flora was collected on riverside. Trace elements content and physicochemical parameters such as nutrients and dissolved oxygen were also determined seasonally at each sampling point, to give insights for the evaluation of water quality and anthropogenic pressure. Both phytoestrogens and phytosterols showed a seasonal variation, with the highest values observed in spring and summer and the lowest in winter. Daidzein (DAID) was found up to 404.0 ng L¡1 in spring and coumestrol (COUM) was found up to 165.0 ng L¡1 in summer. The mycotoxin deoxynivalenol (DON) was ubiquitously determined with values ranging from 59.5 to 642.4 ng L¡1. Nutrients and metals distribution and concentration varied among sampling stations and seasons. This study revealed for the first time the presence of mycotoxins, various classes of phytoestrogens and stigmasterol (STG) in estuarine water from the Ave River (Portugal), and the evaluation of the water quality confirmed that this estuary is still highly impacted by anthropogenic activities.
- Biodegradation of fluoroquinolones by a bacterial consortiumPublication . Maia, Alexandra S.; Duque, Anouk F.; Ribeiro, Ana R.; Tiritan, Maria E.; Castro, Paula M. L.The present concern in pharmaceuticals in the environment is well known and research studies in this area have been regularly reported. Pharmaceuticals reach the environment by several ways but mostly due to their incorrect disposal and the incomplete elimination during the treatment processes in Wastewater Treatment Plants (WWTP). These residues continuously enter aquatic environments and many of them are resistant to degradation, being so called as pseudo-persistent pollutants. In aquatic compartments, pharmaceutical residues reach concentrations in the ng L-1 to µg L-1 range. This work describes the biodegradation of four fluoroquinolones, Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX), by a bacterial consortium constituted by three bacterial species isolated in our labs, namely F11, FP1 and S2, known to degrade different aromoatic fluorinated compounds. The experiments were conducted in batch mode using a mineral medium supplemented with acetate and 10 mg l-1 of each compound or 10 mg l-1 of a mix of the compounds. The bacterial consortium was capable of aerobic biodegradation of OFL, NOR and CPF during successive feedings of the compounds to the medium, as measured by monitoring removal of the compounds by HPLC-FD and fluoride release by potenciometry. Degradation profile of the fluoroquinolones used in this study indicated that intermediate metabolites were accumulated. Two of the initial constituting strains, F11, belonging to the α-proteobacteria group, and S2, belonging to the Actinobacteria group, were recovered from the medium, F11 predominating in cultures fed with moxifloxacin whereas S2 was mostly found in the remaining cultures. Degradation by single bacteria is under evaluation.
- Biodegradation of ofloxacin, norfloxacin, and ciprofloxacin as single and mixed substrates by Labrys portucalensis F11Publication . Amorim, Catarina L.; Moreira, Irina S.; Maia, Alexandra S.; Tiritan, Maria E.; Castro, Paula M. L.Fluoroquinolone (FQ) antibiotics are extensively used both in human and veterinary medicine, and their accumulation in the environment is causing an increasing concern. In this study, the biodegradation of the three most worldwide used FQs, namely ofloxacin, norfloxacin, and ciprofloxacin, by the fluoroorganic-degrading strain Labrys portucalensis F11 was assessed. Degradation occurred when the FQs were supplied individually or as mixture in the culture medium, in the presence of an easily degradable carbon source. Consumption of individual FQs was achieved at different extents depending on its initial concentration, ranging from 0.8 to 30 μM. For the lowest concentration, total uptake of each FQ was observed but stoichiometric fluoride release was not achieved. Intermediate compounds were detected and identified by LC-MS/MS with a quadrupole time of flight detector analyzer. Biotransformation of FQs by L. portucalensis mainly occurred through a cleavage of the piperazine ring and displacement of the fluorine substituent allowing the formation of intermediates with less antibacterial potency. FQ-degrading microorganisms could be useful for application in bioaugmentation processes towards more efficient removal of contaminants in wastewater treatment plants.
- Chiral analysis of pesticides and drugs of environmental concern: biodegradation and enantiomeric fractionPublication . Maia, Alexandra S.; Ribeiro, Ana R.; Castro, Paula M. L.; Tiritan, Maria ElizabethThe importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF). The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.
- Degradation of Fluoroquinolone Antibiotics and Identification of Metabolites/Transformation Products by LC-MS/MSPublication . Maia, Alexandra S.; Ribeiro, Ana R.; Amorim, Catarina L.; Barreiro, Juliana C.; Cass, Quezia B.; Castro, Paula M.L.; Tiritan, Maria E.Antibiotics are a therapeutic class widely found inenvironmental matrices and extensively studied due to its persistence and implications for multi-resistant bacteria development. Degradation of four fluoroquinolone antibiotics, namely Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX), at 10 mg L-1 using a mixed bacterial culture, was assessed for 60 days. The assays were followed by a developed and validated analytical method of HPLC with Fluorescence Detection using a Luna PFP (2) 3µm column. The optimized conditions allowed picturing metabolites/transformation products formation and accumulation during the process, stating an incomplete mineralization, also shown byfluoride release. OFL and MOX presented the highest (98.3%) and the lowest (80.5%) extent of degradation after 19 days of assay, respectively. Some of these intermediate compounds were identified by LCMS/MS in selected degradation samples. Most of the intermediates were already described as biodegradation and/or photodegradationproducts in different conditions, but new and/or unknown metabolites were also present.
- Development and Optimization of an Online SPE-HPLC-FD Method for Quantification of Fluoroquinolones in Wastewater EffluentsPublication . Meira, Bernardo; Maia, Alexandra S.; Gonçalves, Virgínia M. F.; Ribeiro, Ana R.; Tiritan, Maria E.Fluoroquinolones are antimicrobial agents widely found in environmental matrices and extensively studied due to their persistence and implications for multiresistant bacteria. The presence of fluoroquinolones in the environment is mainly due to the incapability of wastewater treatment plants (WWTPs) to completely remove those compounds. The amount of fluoroquinolones released through effluents depends on the type of treatment used by the WWTPs. So, accurate analytical methods to quantify those compounds on WWTPs process and in effluents are crucial. Solid phase extraction (SPE) coupled to liquid chromatography is a straightforward technique that provides analyte extraction, cleanup, separation and detection while providing a good reproducibility and efficiency. The purpose of this work was the establishment of a novel method for quantification of Ofloxacin, Norfloxacin, Ciprofloxacin and Moxifloxacin on WWTPs effluents using on-line SPE. Samples were injected directly on a restricted access material column LichroCart 25-4 Lichrospher® RP-18 ADS (25 μm) and then transferred to an analytical column Luna PFP (2) (150 x 4.6 mm ID, 100 Å, 3 μm) for separation in isocratic mode with a mixture of 0.1% triethylamine in water (acidified to pH = 2.2 with trifluoroacetic acid) and ethanol as mobile phase; column oven was set at 45ºC. The detection was performed by fluorescence with an excitation wavelength of 290 nm and an emission wavelength of 460 nm. The injection volume of 100 μL of previous preconcentrated sample was compared with larger volume injection of only filtered effluent samples. The study was conducted with effluent samples collected from a municipal WWTP in the north of Portugal.
- Dispersive liquid–liquid microextraction and HPLC to analyse fluoxetine and metoprolol enantiomers in wastewatersPublication . Ribeiro, Ana R.; Gonçalves, Virgínia M. F.; Maia, Alexandra S.; Ribeiro, Cláudia; Castro, Paula M. L.; Tiritan, Maria E.Sample extraction is a major step in environmental analyses due both to the high complexity of matrices and to the low concentration of the target analytes. Sample extraction is usually expensive, laborious, time-consuming and requires a high amount of organic solvents. Actually, there is a lack of miniaturized methodologies for sample extraction and chiral analyses. Here, we developed a dispersive liquid-liquid microextraction (DLLME) to extract the pharmaceuticals fluoxetine and metoprolol, as models of basic chiral compounds, from wastewater samples. Compounds were then analysed by enantioselective high-performance liquid chromatography. We monitored the influence of sample pH, extracting and dispersive solvent and respective volumes, salt addition, extracting and vortexing time. The DLLME method was validated within the range of 1-10 A mu g L-1 for fluoxetine enantiomers and 0.5-10 A mu g L-1 for metoprolol enantiomers. Accuracy ranged from 90.6 to 106 % and recovery rates from 54.5 to 81.5 %. Relative standard deviation values lower than 7.84 and 9.00 % were obtained for intra- and inter-batch precision, respectively.
- Enantiomeric fraction evaluation of pharmaceuticals in environmental matrices by liquid chromatography-tandem mass spectrometryPublication . Ribeiro, Ana Rita; Santos, Lúcia H. M. L. M.; Maia, Alexandra S.; Delerue-Matos, Cristina; Castro, Paula M. L.; Tiritan, Maria ElizabethThe interest for environmental fate assessment of chiral pharmaceuticals is increasing and enantioselective analytical methods are mandatory. This study presents an enantioselective analytical method for the quantification of seven pairs of enantiomers of pharmaceuticals and a pair of a metabolite. The selected chiral pharmaceuticals belong to three different therapeutic classes, namely selective serotonin reuptake inhibitors (venlafaxine, fluoxetine and its metabolite norfluoxetine), beta-blockers (alprenolol, bisoprolol, metoprolol, propranolol) and a beta2-adrenergic agonist (salbutamol). The analytical method was based on solid phase extraction followed by liquid chromatography tandem mass spectrometry with a triple quadrupole analyser. Briefly, Oasis® MCX cartridges were used to preconcentrate 250 mL of water samples and the reconstituted extracts were analysed with a Chirobiotic™ V under reversed mode. The effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) was used to validate the method. Linearity (r2 > 0.99), selectivity and sensitivity were achieved in the range of 20–400 ng L−1 for all enantiomers, except for norfluoxetine enantiomers which range covered 30–400 ng L−1. The method detection limits were between 0.65 and 11.5 ng L−1 and the method quantification limits were between 1.98 and 19.7 ng L−1. The identity of all enantiomers was confirmed using two MS/MS transitions and its ion ratios, according to European Commission Decision 2002/657/EC. This method was successfully applied to evaluate effluents of wastewater treatment plants (WWTP) in Portugal. Venlafaxine and fluoxetine were quantified as non-racemic mixtures (enantiomeric fraction ≠ 0.5). The enantioselective validated method was able to monitor chiral pharmaceuticals in WWTP effluents and has potential to assess the enantioselective biodegradation in bioreactors. Further application in environmental matrices as surface and estuarine waters can be exploited.
- «
- 1 (current)
- 2
- 3
- »