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This study explores the photocatalytic transformation of the antiviral drug abacavir employing different advanced oxidation processes (AOPs) such as UV/TiO2, UV/MOF/H2O2, UV/MOF/S2O82−, UV/Fe2+/H2O2, and UV/Fe2+/S2O82−. All processes appear to be effective in eliminating abacavir within a few minutes, while the evolution profile of the basic transformation product, descyclopropyl-abacavir (TP-247) was also monitored. Moreover, the implementation of the most efficient technologies towards the removal of abacavir in different matrices such as wastewater effluent and leachate was also assessed, revealing that the organic matter present or the inorganic constituents can retard the whole process. Four major transformation products were detected, and their time-evolution profiles were recorded in all studied matrices, revealing that different transformation pathways dominate in each matrix. Finally, the prediction of the toxicity of the major TPs employing ECOSAR software was conducted and showed that only hydroxylation can play a detoxification role in the treated solution. [ABSTRACT FROM AUTHOR]

Persistent, Mobile, Organic Compounds (PMOCs) exhibit a propensity to disseminate within the water cycle and as a result, pose a significant threat to the quality of drinking water. To this point of view, considerable research has been initiated to explore the environmental behavior of the omnipresent tiamulin (TIA), being potential PMOC. In contrast to the parent compound (TIA), its transformation products (TPs) have received relatively limited attention, particularly in the context of their PM (persistent-mobile) characteristics. To address this research gap, an investigation into the phototransformation of TIA was conducted, through solar-simulated experiments in combination with Advanced Oxidation Processes (AOPs). To this end, an innovative suspect-screening methodology, involved comparison of the results obtained for the identified photo-TPs with existing literature data. This enabled us to construct an enhanced high-resolution mass spectrometry (HRMS) database for the purpose of environmental assessments of TIA and its TPs in the environment. In total, 32 TPs were identified, with 18 of them being pioneeringly reported. The principal transformation pathways appeared to involve hydroxylation, oxidation, dealkylation, and the cleavage of the C-O bond. Additionally, a comprehensive monitoring of TIA and its TPs in various environmental compartments, including samples from livestock units, leachates, surface water, and groundwater was accomplished. The highest concentration was observed in solid samples from the livestock unit at 2847 ng/g. Furthermore, both the in silico and in vitro methods to assess the toxicity of TIA and its TPs were performed. The results indicated that TIA and many TPs exhibit an alarming toxicity. Consequently, TIA can be classified as a potential PMOC, with a heightened potential for occurrence in different environmental matrices compared to ascertained PM chemicals. [Display omitted] [ABSTRACT FROM AUTHOR]

The extensive use of parabens in various products in combination with the low removal when treated with conventional methods have resulted in their widespread environmental occurrence. Ethyl-paraben (EtP), methylparaben (MeP) and propylparaben (PrP) are characteristic compounds of this category. Over the last years, Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs) have shown promising results for the removal of organic micropollutants. As parabens commonly coexist in mixtures in aquatic systems, this study investigates the efficiency of UV-C/PMS process to remove EtP, MeP and PrP as a mixture in ultrapure water (UPW) and wastewater (WW). UV-C/PMS process was found to be efficient and high removal percentages were observed for all the parabens. However, the removal was dependent on the complexity of the water matrix. Different ions, as well as the dissolved organic matter that exist in wastewater can significantly influence the degradation of the mixture of parabens in UV-C/PMS process. The transformation was found to proceed through hydroxylation, dealkylation, radical coupling and cleavage of the aromatic rings. Although the toxicity was increased at the first stages in both UPW and WW, almost complete detoxification was achieved after prolonged time accompanied by the degradation of all the generated TPs. UV-C/PMS was also found being able to significantly reduce the toxicity from the wastewater. [Display omitted] • UV-C/PMS was effective to remove ethyl-, methyl- and propyl- p-hydroxybenzoate ester. • The k app values were in the range of 6.27 × 10−2 − 10.51 × 10−2 min using 0.3 mM peroxymonosulfate. • The removal was found to be dependent on the complexity of the water matrix. • Hydroxylated, dealkylated, dimers and aliphatic transformation products were identified. • Low inhibitions 1.5% and 7.6% were achieved in ultrapure and wastewater after 60 and 180 min, respectively. [ABSTRACT FROM AUTHOR]

The application of TiO 2 nanoparticles as photocatalyst for the removal of pharmaceutical compounds from water is extensively applied as an alternative to the conventional treatment processes. However, application of TiO 2 as a powder requires energy costing separation stages to remove the catalyst at the end of the process. Thus, immobilization of the catalyst can be an attractive solution. Aiming to find a good support material for TiO 2 , in this study, the synthesis and characterization of three different PET/TiO 2 photocatalytic beads are described along with their application in the photocatalytic degradation of the anticonvulsant drug pregabalin (PGB). The PET/TiO 2 beads with different contents of TiO 2 filler (10 wt%, 20 wt% and 30 wt%) were synthesized by using an anti-solvent precipitation method and were characterized by different techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Among the different composites, PET/TiO 2 30 wt% beads proved to be the most efficient, achieving almost complete degradation of PGB within 6 h of treatment. The stability and reuse of the synthesized catalysts were also evaluated. Furthermore, the effect of matrix was examined, revealing slower kinetics in high loaded matrices like a leachate. Identification of the arising transformation products (TPs) was conducted using LC-HRMS analysis. Twenty-two TPs were identified, out of which fifteen were detected for the first time herein, stemming from hydroxylation, amidation, oxidation and oxidative deamination of PGB. Finally, the i n silico prediction of their toxicity was conducted based on ECOSAR software revealing mainly the formation of non-toxic compounds. However, amidation can cause the formation of toxic/harmful by-products but they are susceptible to photocatalysis thus being eliminated until the end of treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Cytarabine (CY) is an anticancer drug which has been identified in wastewater influents, effluents, and surface waters. In the present study, the degradation of CY under simulated solar light (SSL), by photo-Fenton (Fe3+/H2O2/SSL) and photo-Fenton-like processes (Fe3+/S2O82−/SSL and [Fe(C2O4)3]3−/H2O2/SSL), was investigated. The major parameters affecting the applied treatments (e.g., concentration of CY, Fe3+, H2O2, and S2O82−) were optimized and CY's complete removal was achieved within 45 min for all techniques used. Mineralization studies indicated that [Fe(C2O4)3]3−/H2O2/SSL treatment was the most efficient procedure since faster kinetics are achieved and higher mineralization percentage is reached compared to the other techniques used. Furthermore, 12 transformation products (TPs) were identified during the applied processes, by high resolution mass spectrometry, four of which were identified for the first time, indicating that CY molecule undergoes hydroxylation and subsequent oxidation, during the applied processes. Moreover, predictions of acute and chronic ecotoxicity of CY and its TPs on fish, daphnia, and green algae were conducted, using in silico quantitative structure activity relationship (QSAR) calculations. According to these predictions, the TPs generated during the studied treatments may pose a threat to aquatic environment. Finally, the efficiency of CY degradation by photo-Fenton and photo-Fenton-like treatment in real wastewater was evaluated, under the optimized conditions, which resulted in lower degradation rate constants compared to ultrapure water. [ABSTRACT FROM AUTHOR]

Omeprazole is one of the world-wide most frequently prescribed and administered pharmaceuticals in humans for the relief of gastro-intestinal disorders. Despite its high worldwide consumption, omeprazole is rarely detected in urban wastewaters and environmental waters. On the other hand, its human urinary metabolites and transformation products formed through abiotic processes in the environment have been recently documented. Despite these available data, however, there is still a lack of information on the extent of environmental fate and occurrence, on elimination mechanisms and efficiencies in waste water treatment plants. In this study, the relevance of photodegradation processes on the environmental persistence of omeprazole under simulated and solar irradiation was investigated. Photodegradation experiments were performed in distilled water, lake, river and seawater, and revealed that the different matrix in natural waters significantly affect the photolytic behavior of the investigated compound. Overall, the results highlight that photodegradation process by solar irradiation significantly contributes to omeprazole degradation and elimination from the aquatic environment. TPs formed through the process were identified and elucidated by using liquid chromatography high resolution mass spectrometry. In total seven TPs were identified, among of which four were also detected as hydrolysis TPs. The Microtox bioassay showed that solar photolysis is efficient to detoxify omeprazole and its TPs in aqueous solutions. Finally, a systematic investigation was conducted in order to provide information on removal efficiency and occurrence of omeprazole and its metabolites/TPs in 8 WWTPs in North West Greece by performing target and suspect screening analysis. The findings revealed the presence of both parent compound and metabolites/TPs in wastewaters. Given, however, the scarce detection of omeprazole at fairly low concentration levels, from analytical and environmental point of view, further attention should be given to metabolites/TPs instead of the parent compound. [ABSTRACT FROM AUTHOR]

The presence of personal care product (PCP) residues in the aquatic environment is an emerging issue due to their uncontrolled release through graywater; for this reason, efforts are being made to develop methods to inactivate or eliminate this class of substances in the environment. In this work, homogeneous photocatalysis has been applied for the degradation of UV filter para-aminobenzoic acid (PABA), which exists in several types of PCPs, in order to identify the optimum degradation conditions. The oxidation of PABA by photo-Fenton and oxalate-induced photo-Fenton (ferrioxalate) processes was investigated, and the effect of various operating variables has been assessed, i.e., Fe (0.0035-0.014 g L), HO (0.025-0.2 g L), T (280-323 K), and type of radiation (UV-A, visible). Furthermore, experiments under optimal conditions have been performed in order to evaluate the transformation pathways and phytotoxicity of the treated PABA solution. [ABSTRACT FROM AUTHOR]

Proton pump inhibitors (PPIs) which include omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole, are extensively used for the relief of gastro-intestinal disorders. Despite their high worldwide consumption, PPIs are extensively metabolized in human bodies and therefore are not regularly detected in monitoring studies. Very recently, however, it has been shown that some omeprazole metabolites may enter and are likely to persist in aquatic environment. Hence, to fully assess the environmental exposures and risks associated with PPIs, it is important to better understand and evaluate the fate and behavior not only of the parent compound but also of their metabolites and their transformation products arising from biotic and abiotic processes (hydrolysis, photodegradation, biodegradation etc.) in the environment. In this light, the purpose of this review is to summarize the present state of knowledge on the introduction and behavior of these chemicals in natural and engineering systems and highlight research needs and gaps. It draws attention to their transformation, the increase contamination by their metabolites/TPs in different environmental matrices and their potential adverse effects in the environment. Furthermore, existing research on analytical developments with respect to sample treatment, separation and detection of PPIs and their metabolites/TPs is provided. [ABSTRACT FROM AUTHOR]

Pharmaceuticals and personal care products (PPCPs) along with illicit drugs (IDs) are newly recognized classes of environmental pollutants and are receiving considerable attention because of their environmental impacts: frequent occurrence, persistence and risk to aquatic life and humans. However, relatively little information is often available with regard to their possible biotic and abiotic transformation products (TPs). This lack of knowledge has resulted in a substantial amount of ongoing effort to develop methods and approaches that would assess their occurrence, degradability potential elimination mechanisms and efficiencies in sewage treatment plants as well as environmental and human health risks. In this article, an extensive literature survey was performed in order to present the current stage of knowledge and progress made in the occurrence of TPs of PPCPs and IDs in raw and treated wastewaters. Apart from the TPs resulting from structural transformations of the parent compound in the aquatic environment or in technological treatment facilities (e.g. sewage and drinking water treatment plants), free metabolites and drug conjugates formed during human metabolism have also been included in this review as they are also released into the aquatic environment through wastewaters. Their concentration levels were reported in influents and effluents of WWTPs, hospital effluents and their removals in the treatment plants were discussed. Finally, information on the toxicity of TPs has been compiled when available. [ABSTRACT FROM AUTHOR]

Persistent, mobile, and toxic chemicals (PMT), such as the antimycotic climbazole-(CBZ), proliferate in water cycle and imperil drinking water quality, sparking off research about their environmental fate. Unlike the parent compound, its transformation products-(TPs) are scarcely investigated, much less as PMTs. To this end, phototransformation of CBZ was investigated. A novel suspect-screening workflow was developed and optimized by cross-comparing the results of the identified photo-TPs against literature data to create an enhanced HRMS-database for environmental investigations of CBZ/TPs in the water cycle. In total, 24 TPs were identified, 14 of which are reported for the first time. Isomerism, dechlorination, hydroxylation, and cleavage of the ether or C-N bond are suggested as the main transformation routes. A screening of CBZ/TPs was conducted in wastewater, leachates, surface, and groundwater, revealing a maximum concentration of 464.8 ng/L in groundwater. In silico and in vitro methods were used for toxicity assessment, indicating toxicity for CBZ and some TPs. Seemingly, CBZ is rightly considered as PMT, and a higher potential to occur in surface or groundwater than non-PM chemicals appears. Likewise, the occurrence of TPs due to PMT properties or emission patterns was evaluated. [Display omitted] • Phototransformation of CBZ and transformation pathways were investigated. • 24 photo TPs were identified, 14 of which are reported for the first time. • Semi-quantitation was applied for suspect screening of CBZ/TPs in the water cycle. • In silico / in vitro methods revealed toxicity for the parent CBZ and some TPs. • Persistence, mobility and toxicity criteria were fulfilled for CBZ and two TPs. [ABSTRACT FROM AUTHOR]

This study focused on the Analytical Quality by Design (AQbD) optimization of the chromatographic separation and mass spectrometric detection of a wide group of structurally heterogeneous model pharmaceutical compounds (PhCs) and transformation products (TPs), chosen to cover the challenging issues of the co-presence of compounds characterized by (i) a wide range of physicochemical properties, (ii) the same mass transitions, and (iii) different ionisation modes. Italian consumption of PhCs were also considered as election criteria of target analytes. Octadecyl and pentafluorophenyl stationary phases, acetonitrile/methanol ratios and acidity of the eluents, column temperature, initial organic phase percentage, and elution gradient were investigated by AQbD, aiming at optimizing critical resolutions, sensitivities, and analysis time. Statistically significant models were obtained in most cases with fitting and cross-validation coefficients in the ranges of 0.681-0.998 and 0.514-0.967, respectively. After optimization, the analysis of target analytes was performed in a single chromatographic run, adopting a mixed acquisition mode based on scheduled acquisition windows comprising both single polarity and continuous polarity switching. For most investigated analytes the method provided detection limits in the sub-ng/L to low ng/L range, meeting for macrolides the sensitivity requested by the "Watch List" 2018/840/EU. The optimized method was applied to the direct injection analysis of PhCs and TPs in four wastewater treatment plant (WWTP) effluents and surface water (SW) samples collected in the receiving water bodies. Absolute values of matrix effect were found to be far higher than 20% for most target analytes in most samples. Seventeen PhCs and two TPs were quantified in at least one sample, at the wide concentration range of about 1-3200 ng/L. The most occurring PhCs in both WWTP effluents and SWs were levofloxacin (202-1239 and 100-830 ng/L), furosemide (865-3234 and 230-880 ng/L), ketoprofen (295-1104 and 270-490 ng/L), and ibuprofen (886-3232 and 690-1440 ng/L). [ABSTRACT FROM AUTHOR]

The present study comprehensively investigates the phototransformation and ecotoxicity of a mixture of twelve pharmaceutically active compounds (PhACs) susceptible to photolysis. Namely, three antibiotics (ciprofloxacin, levofloxacin, moxifloxacin), three antidepressants (bupropion, duloxetine, olanzapine), three anti-inflammatory drugs (diclofenac, ketoprofen, nimesulide), two beta-blockers (propranolol, timolol) and the antihistamine ranitidine were treated under simulated solar irradiation in ultra-pure and river water. A total of 166 different transformation products (TPs) were identified by ultra-high performance liquid chromatography coupled with Orbitrap high resolution mass spectrometry (UHPLC–Orbitrap HRMS), revealing the formation of twelve novel TPs and forty-nine not previously described in photolytic studies. The kinetic profiles of the major TPs resulting from a series of chemical reactions involving hydroxylation, cleavage and oxidation, dehalogenation, decarboxylation, dealkylation and photo substitution have been investigated and the transformation pathways have been suggested. Additionally, an in vitro approach to the toxicity assessment of daphnids was contrasted with ecotoxicity data based on the Ecological Structure Activity Relationships (ECOSAR) software comprising the in silico tool to determine the adverse effects of the whole mixture of photolabile parent compounds and TPs. The results demonstrated that photolysis of the target mixture leads to a decrease of the observed toxicity. Unlabelled Image • Photo fate of a multi-component mixture of 12 PhACs • Identification of 166 transformation products by HRMS • In silico toxicity prediction of parent compounds and TPs using ECOSAR • In vitro toxicity assessment using D. magna [ABSTRACT FROM AUTHOR]

The photocatalytic activity of two bio-based polymer photocatalysts [poly(ethylene terephthalate)-TiO 2 (PET-TiO 2) and poly(L-lactic acid)-graphene oxide-TiO 2 (PLLA-GO-TiO 2)] towards Tamoxifen (TAM), Cyclophosphamide (CP), Cytarabine (CYT) and 5-Fluorouracil (5-FLU) removal was explored and compared. The highest photocatalytic activity for the degradation of the cytostatic drugs was accomplished by PET-TiO 2. Among the contaminants, TAM was the most easily removed, requiring 90 min for complete elimination, while CP showed the highest resistance to photocatalysis, not being completely removed after 6 h. Liquid chromatography coupled with high-resolution mass spectrometry analysis was employed for the identification of several transformation products (TPs) and potential pathways were proposed. A total of seventy (70) TPs including thirty-four (34) novel ones detected in AOPs were identified. The ecotoxicity of the mixture of the cytostatic drugs and TPs formed during the photocatalytic treatment was evaluated using Daphnia magna assay and was associated with the occurrence of specific TPs during the treatment process. The follow-up ECOSAR (Ecological Structure Activity Relationship) analysis further elucidated that only minor chemical transformations, such as the hydroxylation or the oxidative opening of an aromatic ring system, could hamper the adverse effects of cytostatic drugs in aquatic species. Such a comparative study on the mixture toxicity of cytostatics and their TPs is presented for the first time. Unlabelled Image • Effective photocatalytic degradation of a mixture of four cytostatic drugs • Increased efficiency of the nanocomposite PET/TiO 2 film compared to PLLA/GO/TiO 2 • Identification of 70 transformation products of cytostatics by Q-Orbitrap HRMS • Increased toxicity at the end of treatment via bioassay (D. magna) • In silico toxicity prediction of all transformation products by ECOSAR [ABSTRACT FROM AUTHOR]