Carbamazepine Concentrations Research Articles

Possibility of dopant morphology control in the process of polymer impregnation with pharmaceuticals in a supercritical CO2 medium

In this paper we present the results of polymethylmethacrylate (PMMA) impregnation with carbamazepine (CBZ) in a supercritical carbon dioxide (scCO2) medium at two different temperatures (75 °C and 105 °C) at a constant CO2 density. The obtained impregnated PMMA samples were analyzed by PXRD and Raman spectroscopy techniques. We have found that, irrespective of the impregnation process temperature, CBZ entrapped in the polymer matrix does not crystallize there but a CBZ solution in the PMMA is formed instead. It has been found that the CBZ concentration in the PMMA matrix grows as the impregnation process temperature rises due to the increase in the CBZ equilibrium concentration in the scCO2 phase, at that the conformational state of the CBZ molecules in the PMMA matrix was also found to depend on the impregnation process temperature. Finally, we showed that depending on the impregnation process temperature it is possible to obtain a PMMA matrix with either an opened or a sealed porous structure. In the latter case, not only CBZ, but also CO2 can be entrapped, remaining in the PMMA matrix in the high-density fluid state.

Effects of Exogenous Organic Matter on the Migration of Organic Contaminants with Different Polarities in Soil

Exogenous DOM (dissolved organic matter) plays an important role in the co-migration of organic pollutants, which controlled by many factors. To evaluate the effect of DOM on contaminants migration and reveal the controlling factors, batch sorption experiment was conducted with carbamazepine (CBZ) and sulfamethoxazole (SMX) as two typical pollutants and montmorillonite as medium. Use humic acid to represent DOM. Fourier-transform infrared spectroscopy and dual-beam UV–Vis spectrophotometer was used for sample characterization. The results showed great differences. DOM can reduce the adsorption capacity of SMX by 4.5 times when the SMX concentration reaches 40 mg/L. But for CBZ, its sorption changed from inhibition to promotion as concentration increases. DOM can increase its adsorption capacity by 2.3 times with the increase of CBZ concentration. Contaminant polarity was proved to be the most important factor. The saturated solubility of SMX is low and the Kow is high, indicating that CBZ is more hydrophobic than SMX. DOM has solubilization and competitive adsorption effects on SMX. While for CBZ, competitive adsorption is dominated between low-concentration CBZ and DOM; high-concentration CBZ mainly cause co-adsorption or cumulative adsorption. The molecular weight and concentration of DOM also have a certain influence on co-migration. The higher the molecular weight of DOM, the greater the effect on pollutants sorption. Furthermore, as DOM concentration increases, the lower the inhibition of SMX and low-concentration CBZ sorption, the stronger the promotion of high-concentration CBZ sorption. In a word, the polarity of pollutants can determine whether DOM promotes or inhibits the co-migration. But the nature of DOM only can change the magnitude of that impact.

Evaluating sewer exfiltration in groundwater by pharmaceutical tracers after the 2016 Kumamoto earthquakes, Japan

In April 2016, a series of earthquakes (M 7.3 on the Japan Meteorological Agency scale) occurred in Kumamoto, Japan causing serious damage to underground sewerage networks. In this study, we evaluated sewer exfiltration in groundwater in the Kumamoto area after the earthquakes by using multiple tracers. We used 14 pharmaceuticals, including carbamazepine and crotamiton, and anthropogenic Gd as tracers, and we measured concentrations of these tracers from September 2016 to November 2017 seasonally. The detection frequency of caffeine, carbamazepine, crotamiton, ibuprofen, and anthropogenic Gd ranged from 29% to 45%, and the concentrations of the pharmaceuticals in the groundwater were lower than those in previous studies. The median of all pharmaceutical concentrations did not decrease, whereas the median of the sum of crotamiton and carbamazepine concentrations, which are quantitative sewage markers, decreased with time. The sewer exfiltration rates in September 2016 estimated using carbamazepine, crotamiton, and anthropogenic Gd were 0.59 ± 0.27%, 0.66 ± 0.47%, and 0.11 ± 0.18% of sewage dry weather flow, respectively, indicating that the effect of the earthquakes on sewer exfiltration was small, probably because the damaged sewers were quickly repaired. This study demonstrated that a multiple-tracer approach is useful for evaluating sewer exfiltration after major earthquakes.

Distribution and Ecological Risk Assessment of PPCPs in Drinking Water Sources of Henan Province

The occurrence of emerging pollutants pharmaceuticals and personal care products (PPCPs) in aquatic environments has potential adverse effects on aquatic organisms, and the presence of PPCPs in drinking water sources is very likely to cause harm to human health. The PPCPs pollution in five typical drinking water sources in Henan province was investigated. Moreover, the source of pollutants was analyzed and the relevant ecological risks were evaluated. The results showed that the cumulative concentrations of 20 PPCPs at different sampling sites ranged from 24.2 to 317.6 ng·L-1. Caffeine (CFI) was the highest level contaminant, with the concentration up to 186.4 ng·L-1, followed by sulfamethoxazole (SMX) and ofloxacin (OFC), with detected concentrations up to 70.8 ng·L-1 and 24.2 ng·L-1, respectively. The pollution of PPCPs in Heigangkou drinking water sources was higher than those of other drinking water sources. The comparation of the labile indicator CFI and the conservative indicator carbamazepine (CBZ) concentrations implies that the pollutions from the upstream water and around scattered domestic sewage might be responsible for the PPCPs present in these drinking water sources. The risk quotient (RQ) calculation results indicated that the detected PPCPs in 5 drinking water sources have moderate to high risks to algae, while low to moderate risks to invertebrates and fish. Therefore, attention should be paid to relevant pollution control.

Interplay of stress responses to carbamazepine treatment, whitefly infestation and virus infection in tomato plants

Reclaimed wastewater is increasingly used to irrigate agriculture crops. We have previously shown that carbamazepine (CBZ), an anticonvulsant human medication, not entirely discarded during wastewater purification, induces a stress response in tomatoes grown with roots bathing in CBZ-containing water. Induction of stress-related osmoprotectants (sugars, amino acids, proteins) was conspicuous in CBZ-treated seedlings. Here, tomato seedlings were grown in pots watered with increasing concentrations of CBZ. Soluble sugars effectively reacted to CBZ in both leaves and roots. However, the induction of stress-related amino acids and proteins was relevant in roots, but insignificant in leaves. Therefore, roots may be the site where CBZ stress is exerted. Moreover, roots may protect the whole plant from the pharmaceutical. Tomato crops endure biotic stresses, caused by whitefly (Bemisia tabaci) infestation and by the tomato yellow leaf curl begomovirus (TYLCV) they vector. The interplay between CBZ, TYLCV infection and B. tabaci was studied in tomato. Whiteflies preferred CBZ-treated plantlets than control plants, which may be due to increased amount of sugars in leaves. The increased amount of viruliferous whiteflies on CBZ-treated plants is expected to be accompanied by a rise in virus amounts. In fact, CBZ caused a reduction of TYLCV amounts. CBZ-dependent activation of autophagy degradation may explain this decrease in virus amounts. TYLCV infection mitigates the activation of stress markers associated with CBZ treatment. Altogether, CBZ in the water used to irrigate tomatoes grown in pots causes a relatively weak plant stress response, but is definitively sensed by insect and by virus.

Efficient photocatalytic destruction of recalcitrant micropollutants using graphitic carbon nitride under simulated sunlight irradiation

The ubiquity of micropollutants (MPs) in aquatic environments has attracted increasing concern for public health and ecological security. Compared to conventional biological treatment, photocatalytic processes show more efficiency in degrading MPs, but they require expensive materials and complicated synthesis processes. This study developed an economic photocatalytic process to degrade micropollutants. We synthesized urea-based graphitic carbon nitride (g-C3N4) by a facile one-step pyrolysis method and evaluated the photocatalytic efficiency of carbamazepine (CBZ). Under simulated solar irradiation, g-C3N4 could achieve 100% removal efficiency of 0.1 mg/L CBZ in spiked wastewater effluent within 15 min, and 86.5% removal efficiency in wastewater influent after 20 min of irradiation. The porous structure of g-C3N4 promoted effective charge separation and mass transport of CBZ near the catalyst surface, enabling a high kinetic rate (0.3662 min −1). Reactive oxygen species trapping experiments revealed that superoxide radicals (O2•-) and holes (h+) were the major active radicals. Electron paramagnetic resonance (EPR) further confirmed the presence of O2•-, • OH, 1O2 and holes. The pH, light intensity and initial CBZ concentration were found to have significant impacts on the removal efficiency of CBZ. Possible reaction intermediates were identified and the degradation pathway was proposed. Multiple MPs were selected to further demonstrate photocatalytic efficiency of g-C3N4. The facile synthesis, superior efficiency, and versatility of g-C3N4 make it a promising catalyst for application in tertiary wastewater treatment processes.

Synergistically enhanced heterogeneous activation of persulfate for aqueous carbamazepine degradation using Fe3O4@SBA-15

The exploration of low-cost, high-performance and stable catalytic materials for sulfate radical-based advanced oxidation processes (SR-AOPs) is of great importance. This study presents Fe3O4-wrapped SBA-15 mesoporous silica catalyst (Fe3O4@SBA-15) for persulfate (PS) activation. The Fe3O4@SBA-15 with an Fe3O4 to SBA-15 weight ratio of 3:1 exhibited an impressive carbamazepine (CBZ) removal efficiency of ~100% after 30 min of SR-AOP at an initial pH of 3.0, a temperature of 25 °C, an initial PS concentration of 300 mg L−1 and a catalyst concentration of 0.50 g L−1. The primary oxidizing species produced in the system were identified as SO4− and HO by electron paramagnetic resonance spectra and radical quenching experiments. Benefiting from the synergetic effects of improved Fe3O4 dispersion and enhanced adsorption of CBZ and PS by SBA-15, the as-obtained heterogeneous Fe3O4@SBA-15 catalysts offer large numbers of active sites for free radical generation and high surface concentrations of CBZ and PS for SR-AOPs, as verified by physicochemical characterization and Langmuir−Hinshelwood model analysis. In addition, the activity of Fe3O4@SBA-15 was maintained throughout six successive cycling tests. Various inorganic anions, including Cl−, NO3−, HCO3−, and CO32−, as well as organic material in natural water, exert a negative impact on the Fe3O4@SBA-15 catalyzed SR-AOPs and deserve special attention.

Adding the Mureş River Basin (Transylvania, Romania) to the List of Hotspots with High Contamination with Pharmaceuticals

Background: The Mureș River Basin is a long-term heavily polluted watershed, in a situation of climate changes with decreasing water flow and related decreasing dilution capacity. Here, a mixture of emerging pollutants such as pharmaceuticals were targeted to reveal potential risks regarding the natural lotic ecosystems. Due to the continuous discharge into the environment, pharmaceuticals are gaining persistent organic pollutant characteristics and are considered emerging pollutants. Based on the hazard quotient, this research highlights the dangerous concentrations of carbamazepine, ibuprofen, furosemide, and enalapril in river water. Results: High levels of four pharmaceutical compounds (carbamazepine, ibuprofen, furosemide, and enalapril) and some of their derived metabolites (enalaprilat, carboxyibuprofen, 1-hydroxyibuprofen, and 2-hydroxyibuprofen) were reported in our study in the Mureș River Basin. Overall, pharmaceutical concentrations were found to be highest in the wastewater treatment plant (WWTP) effluent, median downstream of the WWTP, and lowest upstream of the WWTP, as was expected. For all pharmaceutical compounds tested, we recorded concentrations above the limit of quantification (LOQ) in at least one of the sites tested. Carbamazepine exhibited the highest mean values upstream, downstream, and at the WWTP. As expected, the highest concentrations for all the studied pharmaceutical compounds were detected in the WWTP effluent. All Hazard Quotient (HQ) values were below one (on a logarithmic scale in base 10), with the highest values in the WWTP and the lowest in the river upstream of the WWTP. The HQ intervals were in the same range for furosemide, carbamazepine, and ibuprofen at each of the three different sites: upstream WWTP effluent, and downstream. The interval for enalapril stands out as having the lowest HQ at all three sites. Conclusions: Based on these results, the large and complex hydrographical system Mureș River Basin was transformed from a grey area, with little information about pharmaceutical contamination, to a hotspot in terms of contamination with emerging pollutants. Pharmaceutical compound concentrations were found to be the highest in WWTP effluents. The WWTP effluent concentrations were among the highest in Europe, indicating that treatment plants are the primary source of water pollution with pharmaceuticals compounds. The detected levels were higher than the safety limit for carbamazepine and ibuprofen. The determined HQ values imply that the measured levels do pose a threat to the environment for the studied pharmaceuticals. Based on the obtained results, human communities can assess, monitor, predict, and adapt in time to these already-present regional challenges and risks for sustainable use of natural resources, including water and associated products and services.

Environmentally relevant concentrations of carbamazepine induced lipid metabolism disorder of Chinese rare minnow (Gobiocypris rarus) in a gender-specific pattern

Carbamazepine (CBZ), an anticonvulsant and mood stabilizer, is ubiquitous distributed in aquatic environment. Though the toxicity and endocrine disrupting effect of CBZ on non-target organisms have been studied, its lipotoxity are scarcely known. To assess the lipotoxicity of CBZ, 2-month-old Chinese rare minnow were exposed to 0, 1, 10, and 100 μg/L CBZ for 90 d. Obvious dyslipidemia was observed after 30 d and 90 d exposure, whereas overt hyperlipidemia was observed in males at 100 μg/L treatments. Severe lipid droplet accumulation in livers was observed at 10 and 100 μg/L treatments for 30 d and in females, whereas those was observed at all treatments in males. In addition, serious mitochondria damage was observed in males at 100 μg/L treatments. After 90 d exposure, the enzyme activities of FAS and ACCα were significantly increased at 10 and 100 μg/L treatments, whereas HMGCR were markedly increased at 100 μg/L treatments (p < 0.05). However, ACCβ were markedly decreased in females at 10 and 100 μg/L treatments and in males at all treatments (p < 0.05). The transcription levels of fasn, accα, hmgcrα, fdft1, idi1, plin1, plin2, caveolin1, and caveolin2 were significantly increased at 100 μg/L treatments (p < 0.05). Moreover, the body weight was obviously increased at 10 and 100 μg/L treatments in males (p < 0.05). Our results confirmed that environmental relevant concentrations CBZ induced lipid metabolism disorder and mitochondria damage of Chinese rare minnow in a gender-specific pattern, which provided a new insight into the lipotoxicity mechanism of CBZ.

Accumulation of human pharmaceuticals and activity of biotransformation enzymes in fish from two areas of the lower Rio de la Plata Basin

The accumulation of four human pharmaceuticals active compounds (HPhAC) in the muscle of four fish species of the Rio de la Plata Basin were assessed regarding the compound logP and pKa, and fish trophic levels. For Prochilodus lineatus, accumulation was compared to hepatic biotransformation enzymes and fish from two sampling areas with different urbanization degree. Species were the detritivore Prochilodus lineatus, the omnivores Megaleporinus obtusidens and Pimelodus maculatus, and the piscivorous Salminus brasiliensis. Sampling areas were the Inner Rio de la Plata Estuary (RLP), in front of the Buenos Aires Metropolitan Area, and at the Lower Uruguay River (URU), a relatively unpopulated area. Carbamazepine, atenolol, enalapril, and sildenafil concentrations in fish muscle were analyzed by HPLC-MS. EROD, BROD, and GST activities were measured in P. lineatus liver. Average (maximum) concentrations and detection frequency were: Atenolol 24.4 (69.4) μg kg−1, 60%; carbamazepine 5.5 (45.8) μg kg−1, 19%; enalapril 7.0 (56.9) μg kg−1, 28%; sildenafil 17.1 (71.6) μg kg−1, 56%. Enalapril and sildenafil detection in fish was first-time reported. Atenolol and carbamazepine concentrations were positively correlated. No correlation was observed between HPhAC accumulation and logP or pKa. A potential biomagnification trend was observed for atenolol, showing higher accumulation in S. brasiliensis. HPhACs accumulation was higher for P. lineatus collected at URU, but GST and BROD were significantly higher for individuals sampled at RLP and were positively correlated. A significant negative correlation was observed for enalapril and BROD. The study contributes to the knowledge of the accumulation of HPhACs in fish.

Anticonvulsant Effectiveness and Neurotoxicity Profile of 4-butyl-5-[(4-chloro-2-methylphenoxy)methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) in Mice

Protective (antiseizure) effects of 4-butyl-5-[(4-chloro-2-methylphenoxy)-methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) and acute neurotoxic effects were determined in the tonic-clonic seizure model and rotarod test in mice. The interaction profile of four classic antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) with TPL-16 was also determined in the tonic-clonic seizure model in mice. The protective effects of TPL-16 from tonic-clonic seizures (as ED50 values) and acute neurotoxic effects of TPL-16 (as TD50 values) were determined in 4 pretreatment times (15, 30, 60 and 120 min after its i.p. administration), in adult male albino Swiss mice. The interaction profile of TPL-16 with carbamazepine, phenobarbital, phenytoin and valproate in the tonic-clonic seizure model was determined with isobolographic analysis. Total concentrations of carbamazepine, phenobarbital, phenytoin and valproate were measured in the mouse brain homogenates. The candidate for novel antiepileptic drug (TPL-16) administered separately 15 min before experiments, has a beneficial profile with protective index (as ratio of TD50 and ED50 values) amounting to 5.58. The combination of TPL-16 with valproate produced synergistic interaction in the tonic-clonic seizure model in mice. The combinations of TPL-16 with carbamazepine, phenobarbital and phenytoin produced additive interaction in terms of protection from tonic-clonic seizures in mice. None of the total brain concentrations of classic AEDs were changed significantly after TPL-16 administration in mice. Synergistic interaction for TPL-16 with valproate and the additive interaction for TPL-16 with carbamazepine, phenobarbital and phenytoin in the tonic-clonic seizures in mice allows for recommending TPL-16 as the promising drug for further experimental and clinical testing.

Towards a Better Understanding of the Removal of Carbamazepine by Ankistrodesmus braunii: Investigation of Some Key Parameters

Nowadays, water pollution by pharmaceuticals is a major issue that needs an urgent solution, as these compounds, even when found at trace or ultra-trace levels, could have harmful effects on organisms. Carbamazepine (CBZ) is a pharmaceutical product that is detected as a micropollutant in many water resources. Different treatment methods were lately employed for the removal of CBZ, which are often cheap but inefficient or efficient but expensive. Yet, there are limited available studies on the elimination of this molecule by algae despite their well-known highly adaptive abilities. In this study, the biological treatment of CBZ was carried out using the green microalgae, Ankistrodesmus braunii (A. braunii), which has been reported to be particularly resistant to CBZ toxicity in the literature. The respective effects of the culture medium, the initial inoculum, and CBZ concentrations were studied on CBZ removal. Lastly, the mechanism of CBZ elimination by A. braunii was investigated. The presented data clearly demonstrates that the presence of this molecule did not completely repress A. braunii growth or the ability of these algae to remove CBZ; after 60 days of incubation, the highest percentage of CBZ elimination achieved was 87.6%. Elimination was more successful in Bold’s basal medium than in proteose peptone medium. Finally, the removal mechanism was also investigated to provide a better understanding of the transformation mechanism of this molecule. It was shown that the main removal mechanism was the bioaccumulation of CBZ by A. braunii cells, but the biotransformation of the initial CBZ into metabolites was also observed.

Adsorption and removal of a selected emerging contaminant, carbamazepine, using Humic acid, Humasorb and Montmorillonite. Equilibrium isotherms, kinetics and effect of the water matrix

Carbamazepine is an antiepileptic drug that is not easily degraded in the environment. In this study, the removal of carbamazepine, an emerging contaminant, dissolved in deionized water and wastewater matrices by means of their adsorption onto Humic Acid, Humasorb and Montmorillonite was investigated. The effect of various parameters including adsorption time, adsorbent dosage, and initial adsorbate concentration was determined. The optimum exposure time for the removal of carbamazepine by Humic Acid was 30 min and by Humasorb and Montmorillonite were 2 h, in both distilled and wastewater. The maximum percent removal of carbamazepine by Humic Acid, Humasorb and Montmorillonite in deionized water was 90.5 ± 3.1%, 85.2 ± 2.3% and 83.8 ± 4.5% and in wastewater was 87.0 ± 1.5%, 87.3 ± 5.1% and 78.2 ± 1.2%, respectively, when the initial concentration of carbamazepine was 20 µg/mL and the mass of absorbent 100 mg in 10 mL samples. Three isotherms models including Langmuir, Freundlich, and Elovich were applied to the experimental data. It was found that the adsorption isotherms for the two adsorbents best matched Langmuir model indicating surface adsorption from deionized water (R2= 0.986 for Humic Acid, R2 = 0.955 for Humasorb and R2 = 0.865 for Montmorillonite) as well as from wastewater (R2 = 0.893 for Humic Acid, R2 = 0.949 for Humasorb and R2 = 0.984 for Montmorillonite). According to the kinetic studies, the pseudo-second-order kinetic model better fits to the removal of carbamazepine by the three adsorbents from both water matrices. However, pseudo-second-order model cannot exclusively explain the experimental data trend, but it could be explained by diffusion.

Method Validation for the Determination of Carbamazepine in Spiked-saliva Using HPLC-UV for Therapeutic Drug Monitoring Application

Background:: Carbamazepine has been used in the treatment of bipolar disorder, both in acute mania and maintenance therapy, particularly in developing countries. Not only its interaction with various drugs and auto-inducer nature, but the narrow therapeutic range of carbamazepine also makes monitoring necessary to guarantee the adequacy of its safety and therapeutic concentration. To date, the most common biological specimen used for therapeutic drug monitoring (TDM) purposes is still plasma, but saliva can become an alternative biological matrix since its level in saliva strongly correlates with carbamazepine plasma concentration. Objective:: This study validated the bioanalytical method parameters used for carbamazepine in spiked-saliva in accordance with the Food and Drug Administration (FDA) criteria in the Guidance for Industry Bioanalytical Method Validation. Methods: HPLC-UV detector was employed at 285 nm λ with methanol: water: glacial acetic acid (65:34:1) as the mobile phase and C8 as the stationary phase (4.6x150 mm; 5 μm). Results:: The linearity test in a range of 0.0 - 5 μg/mL carbamazepine concentration resulted in a correlation coefficient of 0.999 with 0.20 μg/mL LoD, 0.30 μg/mL LLoQ, and 0.61 μg/mL LoQ. The coefficient of variation and 0iff in the selectivity, accuracy, and precision parameters remained below 20%, indicating fulfillment of the criteria for a bioanalytical method, while the average % recovery was more than 90%. Conclusion:: The currently-developed bioanalytical method has fulfilled the stipulated validation criteria to be used for determining carbamazepine concentration in spiked-saliva as an alternative method for relative bioequivalence studies or TDM application in a clinical setting.

Study on the relationship between adverse drug reactions of carbamazepine and HLA-B*1502 genetic polymorphism and blood concentration

Objective： To study the relationship between genetic polymorphism，blood concentration and adverse drug reactions（ADRs） of carbamazepine（CBZ），so as to promote clinical safety and reasonable use of CBZ.Methods： Clinical medical data of the inpatients treated in Ruijin Hospital Affiliated to School of Medicine，Shanghai Jiao Tong University from 2017 to 2019 were collected retrospectively.Data concerning HLA-B*1502 gene detection and serum concentration of CBZ were collected to analyze the relationship between HLA-B*1502 genotype and ADRs of CBZ in the patients.Results： A total of 148 patients were enrolled for study，of whom 101 patients received HLA-B*1502 genotypes detection，with the genotype of 34 patients being positive，accounting for 33.66%.In the 148 patients，78 were treated with CBZ（53.79%），among whom 60 patients（86 case times） received serum drug concentration detection of CBZ.The serum drug concentration in 53 case times was within the recommended concentration range，accounting for 61.63% of the detected case times，and the serum drug concentration in 32 case times（37.21%） was lower than that of the recommended data.CBZ-related ADRs occurred in 12 cases（15.38%），of which one patient with HLA-B*1502 homozygous mutation developed severe skin ADRs after taking CBZ.Conclusion： There is close association between HLA-B*1502 genotype and skin ADRs induced by CBZ.The treatment window of CBZ is narrow，and the rate of ADRs might be associated with blood concentration of CBZ.Gene detection and blood concentration detection are of great significance to the improvement of the safety of CBZ in clinical practice.

Synergistic effects of UVC and oxidants (PS vs. Chlorine) on carbamazepine attenuation: Mechanism, pathways, DBPs yield and toxicity assessment

The environmental impact and health risk of carbamazepine (CBZ) in water environment has been continuously reported. Ultraviolet C (UVC)/persulfate (PS) and UVC/chlorine (NaClO) processes were confirmed to be able to efficiently eliminate CBZ through the oxidation by reactive radicals (52.82% SO4−· and 44.21% ·OH in UVC/PS system, 53.47% RCS and 43.84% ·OH in UVC/chlorine process, pH 7.0). The second-order rate constants of CBZ reacted with ·OH, SO4−· and RCS were determined to be 8.2 × 109, 9.1 × 108 and 4.2 × 1010 M−1 s−1, respectively. In both processes, increasing oxidants dosage and rising temperature was favorable for elimination, while increasing CBZ concentration retarded its degradation rate. The coexisting of NOM, SO42− and CO32–/HCO3– presented the inhibitory effect, while NO3– promoted the removal. NH4+ exerted an inhibitory effect in UVC/chlorine process, while exerted no obvious influence in UVC/PS system. Cl− posed a promoting role in UVC/PS treatment and a dual effect in UVC/chlorine process. pH affected the quantum yield of chlorine photolysis and the formation of RCS and ·OH. The degradation of CBZ oxidation via UVC/chlorine process was more pH dependent. 12 and 14 CBZ oxidation products were identified in UVC/PS and UVC/chlorine systems, respectively. SO4−·, RCS and ·OH were readily to attack C = C in CBZ molecule, mainly yielding hydroxylated CBZ, epoxy CBZ, pyridine aldehydes and ketones. Of the disinfection by-products (DBPs) assessed, both processes controlled the formation of haloacetic acids, while increased the generation of trichloromethane, especially via UVC/chlorine process. UVC/chlorine process was more economical and effective (EEO UVC/chlorine = 0.2213 kWh L−1), whereas UVC/PS process was safer in terms of DBPs and toxicity control.

Carbamazepine biodegradation and volatile fatty acids production by selectively enriched sulfate‐reducing bacteria and fermentative acidogenic bacteria

AbstractBACKGROUNDThe micropollutant carbamazepine (CBZ) is persistent and resistant to conventional wastewater treatment. This study investigated the role of fermentative acidogenic bacteria (FAB) and sulfate‐reducing bacteria (SRB) for CBZ biodegradation and volatile fatty acid (VFA) production.RESULTSThe experimental results demonstrated that CBZ biodegradation, total organic carbon and sulfate removal efficiency reached 46%, 36% and 98%, respectively, after 144 h of operation with VFA production of acetic acid (20.72 mmol L−1), propionic acid (3.67 mmol L−1) and butyric acid (4.90 mmol L−1). However, the acetate fraction decreased from 78% to 70% with a decrease in chemical oxygen demand/sulfate (COD:SO42−) ratios from 1.06 to 0.35, respectively, suggesting that acetate was partially oxidized by SRB under substrate/COD limiting conditions. The biodegradation performance of SRB + FAB was also compared with that of a mixed microbial community (MMC).CONCLUSIONSUpon increasing the initial CBZ concentration from 42.3 to 169.2 μmol L−1, SRB + FAB exhibited much higher CBZ biodegradation (33%) than MMC (12%). Microbial community analyses confirmed the enrichment of VFA‐producing species including phylum Firmicutes (2.4% to 36.8%) and class Clostridia (1.3% to 29.6%). Moreover, aromatic and nitroaromatic compound‐degrading bacteria such as Escherichia and Desulfovibrio were also enriched. This signifies the applicability of SRB + FAB to pharmaceutical pollutant biodegradation in the environment. © 2020 Society of Chemical Industry (SCI)

Pharmaceuticals as emerging contaminants in the aquatic environment of Latin America: a review.

Pharmaceutical active compounds (PhACs) are environmentally ubiquitous around the world, and the countries of Latin America (LATAM) are not the exception; however there is still little knowledge of the magnitude and conditions of their occurrence in LATAM and of the environmental consequences of their presence. The present work reviews 79 documents published from 2007 to 2019 on the occurrence, concentrations, and sources of PhACs and hormones in surface water (SW), wastewater (WW), and treated wastewater (TWW) in LATAM and on the circumstances of their release to the environment. Research efforts are reported in only ten countries and confirm the presence of 159 PhACs, mainly analgesics and anti-inflammatories, although extraordinarily high concentrations of carbamazepine (830μg/L) and ethinylestradiol (6.8μg/L) were found in Ecuador and Brazil, respectively. The analysis of maximum concentrations and the ecotoxicological risk assessment corroborate that (1) these values exceed the environmental concentrations found in other parts of the world, (2) the environmental risk posed by these concentrations is remarkably high, and (3) there is no statistically significant difference between the maximum concentrations found in WW and those found in TWW. The main source of PhACs in LATAM's aquatic environment is WW; hence, these countries should direct substantial efforts to develop efficient and cost-effective treatment technologies and plan and apply WW management strategies and regulations. This analysis presents the current states of occurrence, concentrations, and sources of PhACs in the aquatic environment of LATAM and outlines the magnitude of the environmental problem in that part of the world.

Enhanced degradation of carbamazepine in FeOCl based Photo-Fenton reaction

Carbamazepine (CBZ) is one of the contaminants of emerging concerns due to its broad distribution in water environments. The present study evaluated various photo-Fenton reactions to achieve enhanced CBZ removal using FeOCl as the photo-Fenton catalyst that exhibited high activity in ·OH generation at a wide range of pH. The effects of UV irradiation, H2O2 concentration, initial CBZ concentration and catalyst dosage on the CBZ degradation efficiency were evaluated with uncertainty analysis. The H2O2 concentration of 10 μM, a catalyst dosage of 0.2 g/L, and the initial concentration of CBZ of 100 μM led to the highest CBZ removal rate of 92 % under UV/H2O2/FeOCl system within 0.5 h The effects of common anions (i.e., CO32−, HCO3, SO42−, NO3- and Cl-) on the CBZ degradation were studied. Three possible degradation pathways and three major degradation by-products were analyzed by LC−ESI−MS, which would provide new insight into the degradation mechanisms of CBZ in photo-Fenton reactions.

Carbamazepine sorption characteristics onto bentonite clay: Box-Behnken process design

A comprehensive study has been hold as a function of ionic strength, pH, equilibrium (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models), kinetic (pseudo-first order, pseudo-second order and intraparticular kinetic models) and thermodynamic for the removal of carbamazepine (CBZ) from its aqueous solutions onto bentonite. A statistical experimental design method (Box-Behnken) has been applied for the optimal adsorption conditions (0.089 g resin/10.31 mL solution under 144 rpm mixing speed of shaking bath) in order to achieve the maximum yield (≈80% removal). Partition coefficient (PC) was also employed for the evaluation of the bentonite clay's performance. The equilibrium time was determined as 15 min depending on the kinetic study, where the maximum adsorption capacity (2.3550 mg g-1) and PC (0.0684 mg g-1 μM-1) were achieved for an initial CBZ concentration of ≈30 mg L-1. Effects of pH (3, 5, 7, 9 and 11) and ions (chloride, fluoride and lead) on the CBZ adsorption have been explored. The acidic media (pH ~ 3) enhanced the removal, while ionic strength caused to drop the adsorption from 22 to 51% depending on the ion and its concentration (0.17, 0.86 and 1.71 mol L-1 for chloride; 0.24, 0.48 and 0.95 mol L-1 for floride; 0.03, 0.15 and 0.30 mol L-1 for lead) in the solution. Finally, the nature of the adsorption process for the CBZ removal onto bentonite has been detected to be a non-spontaneous and endothermic, having a tendency to an irregular structure.