Pharmaceutical Micropollutants Research Articles

General approach for electrochemical detection of persistent pharmaceutical micropollutants: Application to acetaminophen.

We propose in this work a general and versatile methodology for electrochemical monitoring of persistent pharmaceutical micropollutants. The system presented is based on an electroactive and electropolymerized hapten (mimetic molecule of the pollutant to be detected) and a specific antibody that competitively binds either the hapten or the pollutant. The current delivered by the device depends on this competitive equilibrium and therefore on the pollutant's concentration. The determination of the pharmaceutical product operates within minutes, using square wave voltammetry without labeling or addition of a reactant in solution; the competitive hapten/antibody transduction produces a "signal-on" (a current increase). Applied to acetaminophen, this electrochemical immunosensor presents a very low detection limit of ca. 10 pM, (S/N=3) and a very high selectivity towards structural analogs (aspirin, BPA, and piperazine) even in a mixture.

Effects of Continuous Pollution by Pharmaceutical Micropollutants on the Fouling of a Membrane Bioreactor Treating Domestic Wastewater

Membrane bioreactors (MBR) are increasingly used for domestic wastewater treatment and reuse and great concerns have been raised in the last decade about some emerging trace pollutants found in aquatic environment, notably pharmaceutical products. As a consequence, the removal of pharmaceutical micropollutants by MBRs has been extensively investigated but there is still a lack of knowledge on the effects of the current presence of pharmaceutical micropollutants in domestic wastewaters on MBR fouling. Among the different pharmaceuticals, it was decided to focus on carbamazepine (CBZ), an anti-epileptic drug, because of its occurrence in domestic wastewaters and persistence in biological processes including MBRs. The chemical analysis of soluble microbial products (SMPs) in the supernatant showed that a continuous introduction of CBZ into a submerged MBR via the feed (about 90 µg/L CBZ in the feed) led to a significant increase in the concentration of proteins whereas no significant change was found for polysaccharides. Size exclusion high performance liquid chromatography (HPLC-SEC) analysis showed that the addition of CBZ induced a significant increase of 10-100 kDa proteins in the supernatant and a slight decrease of 100-1000 kDa proteins. After addition of CBZ a significant increase of transmembrane pressure (TMP) in the MBR was observed, which indicates that the increase of the quantity of 10-100 kDa proteins led to a more severe fouling caused by internal fouling in the biocake that was formed on MBR membrane surface. This study also suggests that 10-100 kDa proteins might play a major role in the TMP jump phenomenon. Moreover it was found that addition of CBZ to the MBR affected the biological activities, as a slight inhibition of the exogenous respiration rate was observed.

Degradation of pharmaceuticals and metabolite in synthetic human urine by UV, UV/H2O2, and UV/PDS.

To minimize environmental pharmaceutical micropollutants, treatment of human urine could be an efficient approach due to the high pharmaceutical concentration and toxic potential excreted in urine. This study investigated the degradation kinetics and mechanisms of sulfamethoxazole (SMX), trimethoprim (TMP) and N4-acetyl-sulfamethoxazole (acetyl-SMX) in synthetic fresh and hydrolyzed human urines by low-pressure UV, and UV combined with H2O2 and peroxydisulfate (PDS). The objective was to compare the two advanced oxidation processes (AOPs) and assess the impact of urine matrices. All three compounds reacted quickly in the AOPs, exhibiting rate constants of (6.09-8.53) × 10(9) M(-1)·s(-1) with hydroxyl radical, and (2.35-16.1) × 10(9) M(-1)·s(-1) with sulfate radical. In fresh urine matrix, the pharmaceuticals' indirect photolysis was significantly suppressed by the scavenging effect of urine citrate and urea. In hydrolyzed urine matrix, the indirect photolysis was strongly affected by inorganic urine constituents. Chloride had no apparent impact on UV/H2O2, but significantly raised the hydroxyl radical concentration in UV/PDS. Carbonate species reacted with hydroxyl or sulfate radical to generate carbonate radical, which degraded SMX and TMP, primarily due to the presence of aromatic amino group(s) (k = 2.68 × 10(8) and 3.45 × 10(7) M(-1)·s(-1)) but reacted slowly with acetyl-SMX. Ammonia reacted with hydroxyl or sulfate radical to generate reactive nitrogen species that could react appreciably only with SMX. Kinetic simulation of radical concentrations, along with products analysis, helped elucidate the major reactive species in the pharmaceuticals' degradation. Overall, the AOPs' performance was higher in the hydrolyzed urine than fresh urine matrix with UV/PDS better than UV/H2O2, and varied significantly depending on pharmaceutical's structure.

Simultaneous Determination of Pharmaceutical and Pesticides Compounds by Reversed Phase High Pressure Liquid Chromatography

A reversed phase HPLC method has been developed for the simultaneous separation and quantification of a mixture, constituted by a total of thirteen selected pollutants: pharmaceutical products and others compounds including one hormone, a pesticide, a natural marker and solvents. For each pollutant, the calibration curve shows a good linearity (r² ≥ 0.998) over the concentration range of 1.0 × 10-5 – 5 × 10-8 mol/L. The limit of detection at 230 nm is ranging from 5.0 × 10-6 to 4.0 × 10-5 mg/mL, whereas the limit of quantification is in the range 1.8 × 10-5 - 1.2 × 10-4 mg/mL depending on the selected pollutant. The separation of the complex mixture was performed on a Hypersil Gold column 100 mm × 2.1 mm (dp=3 μm) using a multi-step linear gradient at 210, 230 and 280 nm. This method is well adapted for the detection of pharmaceutical compounds or micropollutants at low concentrations as a routine analysis but also as an alternative method to sophisticated ones like HPLC-MS or HPLC-fluorescence.

Effects of pharmaceutical micropollutants on the membrane fouling of a submerged MBR treating municipal wastewater: Case of continuous pollution by carbamazepine

Membrane bioreactor (MBR) is increasingly used for municipal wastewater treatment and reuse and great concerns have been raised to some emerging trace pollutants found in aquatic environment in the last decade, notably the pharmaceuticals. As a consequence the removal of pharmaceutical micropollutants by MBRs has been extensively investigated. But there is still a lack of knowledge on the effects of the current presence of pharmaceutical micropollutants in domestic wastewaters on MBR fouling. Among the different pharmaceuticals, it was decided to focus on carbamazepine (CBZ), an anti-epileptic drug, because of its occurrence in domestic wastewaters and persistency in biological processes including MBRs. This paper focuses on the effects of continuous carbamazepine pollution on MBR fouling. A continuous introduction of CBZ into the MBR via the feed (about 90 μg L−1 CBZ in the feed) provoked a TMP jump. It occurred just 1 day after the addition of CBZ in MBR and a significantly higher increase rate of TMP was also observed after 1 day after addition of CBZ in MBR, as compared to that before addition of CBZ. This indicates that the pharmaceutical stress induced by CBZ causes more severe membrane fouling. Addition of CBZ was shown to induce a significant increase of the concentration of proteins in the supernatant at the beginning several days then stabilized to original level whereas no significant change was found for polysaccharides. HPLC-SEC analysis showed that addition of CBZ induced a decrease of 100–1000 kDa protein-like SMPs and a more significant increase of 10–100 kDa protein-like SMPs in the supernatant. Moreover it was found that addition of CBZ in the MBR affected the sludge microbial activities, as a slight inhibition (about 20%) of the exogenous respiration rate was observed. The increased membrane fouling could be related to the change in biomass characteristics and supernatant quality after addition of CBZ in MBR. This study allows also suggesting that 10–100 kDa protein-like SMPs might accumulate inside the biocake that was formed on the membrane surface during MBR operation and play an important role in the TMP jump phenomenon.

Evaluation of membrane bioreactor on removal of pharmaceutical micropollutants: a review

Municipal wastewater reclamation and reuse has become an important solution in many places around the world to deal with water scarcity problems. Among the available treatment approaches, membrane bioreactor (MBR) has a great potential to become a key element in municipal wastewater reclamation and reuse schemes due to its significantly higher treated effluent quality as compared to the conventional activated sludge process. As great concerns have been raised to some emerging trace pollutants found in aquatic environment in the last decade, notably the pharmaceuticals, removal of pharmaceutical micropollutants by MBR or MBR-related processes should be evaluated to further understand the status of MBR in different wastewater treatment and reuse schemes. This paper gives an overview on removal of pharmaceutical micropollutants by MBR or MBR-related processes, such as activated carbon-assisted MBR and combined membrane bioreactor and reverse osmosis process.

Shear-induced hydrodynamic cavitation as a tool for pharmaceutical micropollutants removal from urban wastewater

In this study, the removal of clofibric acid, ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac residues from wastewater, using a novel shear-induced cavitation generator has been systematically studied. The effects of temperature, cavitation time and H2O2 dose on removal efficiency were investigated. Optimisation (50°C; 15min; 340mgL−1 of added H2O2) resulted in removal efficiencies of 47–86% in spiked deionised water samples. Treatment of actual wastewater effluents revealed that although matrix composition reduces removal efficiency, this effect can be compensated for by increasing H2O2 dose (3.4gL−1) and prolonging cavitation time (30min). Hydrodynamic cavitation has also been investigated as either a pre- or a post-treatment step to biological treatment. The results revealed a higher overall removal efficiency of recalcitrant diclofenac and carbamazepine, when hydrodynamic cavitation was used prior to as compared to post biological treatment i.e., 54% and 67% as compared to 39% and 56%, respectively. This is an important finding since diclofenac is considered as a priority substance to be included in the EU Water Framework Directive.

Preliminary assessment of terrestrial microalgae isolated from lichens as testing species for environmental monitoring: Lichen phycobionts present high sensitivity to environmental micropollutants

Bioassays constitute a tool for pollution analysis providing a holistic approach and high-quality indication of the toxicity. Microbioassays allow evaluating the toxicity of many samples, implying lower costs and enabling routine monitoring and pollution control. But tests conducted so far are limited to the use of a small number of taxa. Lichens are excellent bioindicators of pollution with great ecological significance. Studies show that the phycobiont is more sensitive to pollutants than the mycobiont. Phycobiont have features such as adaptation to anhydrobiosis and relatively rapid growth in vitro, making them suitable for microbioassays. Our aim is to determine the sensitivity of phycobionts to the pharmaceutical micropollutants carbamazepine and diclofenac as a preliminary step for the development of a toxicity microbioassay based on phycobionts. Optical dispersion and chlorophyll autofluorescence were used as endpoints of toxicity on two algal species showing that suspensions present cyclic and taxon specific patterns of aggregation. Trebouxia TR9 suspensions present a very high grade of aggregation while Asterochloris erici cells do not. Both micropollutants alter optical properties of the suspensions of both species. No significant alteration of chlorophyll autofluorescence by carbamazepine is observed. A. erici chlorophyll autofluorescence is extremely sensitive to diclofenac but the effect is not dependent on the drug concentration or on the time of exposure. Differently, TR9 only shows punctual chlorophyll alterations. Fluctuations in optical dispersion may indicate changes in the population structure of the species, including reproductive strategy. A. erici seems more sensitive to micropollutants, is better characterized and is available from commercial collections.

Heterogeneous photocatalytic treatment of pharmaceutical micropollutants: Effects of wastewater effluent matrix and catalyst modifications

This study evaluates the applicability of TiO2-based photocatalysts for the treatment of pharmaceutical micropollutants in secondary wastewater effluent (SWE). Photolytic experiments using SWEs with different compositions demonstrated that the rates of photocatalytic degradation of acetaminophen and carbamazepine inversely correlated with the concentration of dissolved organic carbon (DOC), regardless of the type of applied light source and initial pharmaceutical concentration. The critical relevance of organic matter to the scavenging behavior of SWE was further verified by assessing the photocatalytic performance as a function of the concentrations of potential effluent-derived quenchers (i.e., NO3−, Cl−, alkalinity, and humic acid). Kinetic comparison of the degradation of trace levels of pharmaceuticals (i.e., caffeine, cimetidine, propranolol, and sulfamethoxazole) using TiO2/UV-A, TiO2/UV-C, and H2O2/UV-C systems revealed that heterogeneous processes showed more significant performance reduction with increasing DOC concentration; this result indicates that organic matter plays dual roles in the scavenging activity of an effluent matrix: (1) OH radical (OH) quenching and (2) active-site coverage. TiO2 surface modifications (i.e., Pt and SiOx loading) accelerated the degradation of all the tested pharmaceuticals in SWEs to a certain degree. Particularly, the relevant altered surface affinity preferentially increased the susceptibility of specific pharmaceuticals to photocatalytic treatment. The presence of the effluent matrix substantially impaired the performance of visible-light-active photocatalysts in most cases. However, photocatalytic pharmaceutical degradation on Pt-doped TiO2, which occurs via direct charge transfer, was much less hindered in SWEs than that on Pt-deposited WO3, which occurs via OH-mediated oxidation.

Photo-regenerable multi-walled carbon nanotube membranes for the removal of pharmaceutical micropollutants from water

Pharmaceutical micropollutants fall in the category of "emerging contaminants" in water because of their prevalence and persistence in the aqueous environment, and because of a poor understanding of their low-dose exposure effects on human and animal populations. In this study, photo-regenerable multiwalled carbon nanotube membranes with variable water permeabilities were produced by embedding hierarchical TiO2 structures (having porous, spherical morphology) onto a pre-deposited bed of multi-walled carbon nanotubes (MWNTs) using a modified sol-gel technique. These MWNT-TiO2 composites and their constituent materials were characterized by analytical electron microscopy, surface charge measurement, thermogravimetric analysis, and hydrophobicity determination. The adsorption removal potential of MWNT-TiO2 membranes was demonstrated for three representative pharmaceuticals: acetaminophen, carbamazepine and ibuprofen. The peak initial removal percentages of the pharmaceuticals by the MWNT-TiO2 membranes were 80%, 45%, and 24% for carbamazepine, ibuprofen, and acetaminophen, respectively. The ability of the membranes to be regenerated, once they were saturated with the pharmaceutical compounds, was verified by repeating the adsorption removal experiment on the same membranes after exposure to UV light at 254 nm. Peak removal efficiencies after regeneration were 55%, 32%, and 19% for carbamazepine, ibuprofen, and acetaminophen, respectively, indicating some loss in sorptive capacity upon regeneration. Furthermore, the effect of pH on adsorption of ibuprofen, the pharmaceutical that attained the highest mass loading on the sorbent at equilibrium saturation, was studied and its mechanism of adsorption was proposed at pH below pKa.

Micropollutant Point Sources in the Built Environment: Identification and Monitoring of Priority Pharmaceutical Substances in Hospital Effluents

A method is described for the identification of priority micropollutants (pharmaceuticals) in the aquatic environment originating from hospitals. The lack of data on the range and volume of prescribed pharmaceuticals, and on their behaviour in the environment, presented a considerable challenge to the initial selection process. The final selection of pharmaceutical substances to be included in the monitoring campaigns was based on literature data, existing priority lists, national consumption patterns and expert input from within the regions (Northwest Europe). Fifteen micropollutant compounds were identified from the diverse range of reported and prescribed pharmaceuticals in the healthcare sector: atenolol, carbamazepine, diclofenac, naproxen, lidocaine, ifosphamide, cyclophosphamide, ciprofloxacin, erythromycin, clarithromycin, sulfamethoxazole, iopromide, iopamidol, diatrizoate, and bezafibrate. Eight hospital locations in six countries were monitored for periods ranging from several weeks to one year. Samples were taken from hospital effluent (sewers) flow - proportionally and analysed by LC - MS - MS. The obtained results indicate that hospitals are significant point sources for some (especially x - ray contrast media and antibacterials) but not all pharmaceutical micropollutants. Hospital contribution to overall load in the sewers at entry to waste water treatment plants ranged from <10% for substances also used in the communities (e.g. diclofenac and atenolol), to well in excess of 50% for antibiotics and x - ray contrast media. A detailed understanding of emission pathways within the urban environment is required in order to inform related political decision making. This project demonstrated a route towards this understanding and also highlighted the difficulties and barriers that need to be overcome in the process.

Continuous-flow photocatalytic treatment of pharmaceutical micropollutants: Activity, inhibition, and deactivation of TiO2 photocatalysts in wastewater effluent

Titanium dioxide (TiO2) photocatalysts have been shown to be effective at degrading a wide range of organic micropollutants during short-term batch experiments conducted under ideal laboratory solution conditions (e.g., deionized water). However, little research has been performed regarding longer-term photocatalyst performance in more complex matrices representative of contaminated water sources (e.g., wastewater effluent, groundwater). Here, a benchtop continuous-flow reactor was developed for the purpose of studying the activity, inhibition, and deactivation of immobilized TiO2 photocatalysts during water treatment applications. As a demonstration, degradation of four pharmaceutical micropollutants (iopromide, acetaminophen, sulfamethoxazole, and carbamazepine) was monitored in both a pH-buffered electrolyte solution and a biologically treated wastewater effluent (WWE) to study the effects of non-target constituents enriched in the latter matrix. Reactor performance was shown to be stable over 7d when treating micropollutants in buffered electrolyte, with 7-d averaged kobs values (acetaminophen=0.97±0.10h−1; carbamazepine=0.50±0.04h−1; iopromide=0.49±0.03h−1; sulfamethoxazole=0.79±0.06h−1) agreeing closely with measurements from short-term circulating batch reactions. When reactor influent was switched to WWE, treatment efficiencies decreased to varying degrees (acetaminophen=40% decrease; carbamazepine=60%; iopromide=78%; sulfamethoxazole=54%). A large fraction of the catalyst activity was recovered upon switching back to the buffered electrolyte influent after 4d, suggesting that much of the observed decrease resulted from reversible inhibition by non-target constituents (e.g., scavenging of photocatalyst-generated OH). However, there was also a portion of the decrease in activity that was not recovered, indicating WWE constituents also contributed to photocatalyst deactivation (acetaminophen=6% deactivation; carbamazepine=24%; iopromide=16%; sulfamethoxazole=25%). Experiments conducted using pretreated WWE and synthetic WWE mimic solutions indicated that both effluent organic matter and inorganic constituents in WWE contributed to the observed photocatalyst inhibition/deactivation. Analysis of immobilized TiO2 thin films after 4d of continuous treatment of the WWE matrix indicated minor deterioration of the porous film and formation of surface precipitates enriched in Al and Ca. Results demonstrated the marked influence of non-target constituents present in complex matrices on long-term photocatalyst activity and highlighted the need for further study of this important issue to advance the development of practical photocatalytic water treatment technologies.

TiO2-photocatalyzed transformation of the recalcitrant X-ray contrast agent diatrizoate

Iodinated X-ray contrast media (ICM) are biologically recalcitrant chemicals that are often detected in wastewater-impacted environments at higher concentrations than other pharmaceutical micropollutants of concern. Diatrizoate is an anionic ICM that is especially resistant to conventional wastewater and drinking water treatment processes. This study examined the aqueous photocatalytic treatment of diatrizoate using nanophase titanium dioxide (TiO2). Experiments demonstrated that diatrizoate can be degraded in aqueous TiO2 suspensions illuminated with ultraviolet-A (UVA) light. In oxic solutions, diatrizoate degraded principally via oxidation by adsorbed hydroxyl radicals (OH), releasing iodine substituents stoichiometrically, but causing little mineralization of organic carbon and nitrogen. Introduction of OH scavengers significantly slowed the rate of photocatalytic degradation. At circumneutral pH, diatrizoate was oxidized much more slowly than iopromide, a nonionic ICM, in part because of unfavorable electrostatic interactions with the negatively charged TiO2 surface; increased rates of oxidation observed at lower pH conditions can be attributed to more favorable diatrizoate-TiO2 sorptive interactions. Experiments also demonstrated that diatrizoate was degraded at appreciable rates in anoxic solutions, and reductive dehalogenation products are identified by liquid chromatography–mass spectrometry. The higher selectivity of reductive processes suggests a promising strategy for targeted treatment of recalcitrant ICM in organic-rich matrices like wastewater effluent.

Removal of persistent pharmaceutical micropollutants from sewage by addition of PAC in a sequential membrane bioreactor

The performance of a membrane bioreactor operating in a sequential mode (SMBR) using an external flat-plate membrane was investigated. After 200 days of operation, a single addition of 1 g L −1 Powdered Activated Carbon (PAC) was added directly into the mixed liquor in order to enhance the simultaneous removal of nutrients and pharmaceutical micropollutants from synthetic urban wastewater. Throughout the entire operation (288 days), Chemical Oxygen Demand (COD) removal efficiencies were up to 95%, ammonium nitrogen removal was maintained over 70–80%, whereas phosphorus removal achieved only high values (around 80%) after PAC addition. During the operation of the SMBR without PAC addition, micropollutants which exerted a more recalcitrant behaviour were carbamazepine, diazepam, diclofenac and trimethoprim, with no significant removal. On the other hand, moderate removals (42–64%) were observed for naproxen and erythromycin, whereas ibuprofen, roxithromycin and fluoxetine were removed in the range of 71–97%. The addition of PAC into the aeration tank was a successful tool to improve the removal of the more recalcitrant compounds up to 85%. The highest removal with PAC was observed for carbamazepine, trimethoprim as well as for roxithromycin, erythromycin and fluoxetine. The latter four compounds have amine groups and pKa in the range 6.7–10.1, thus the interaction between PAC and the positively charged amino groups might be the cause of their comparatively better results. Microbial ecology present in the biomass showed a higher abundance of Accumulibacter phosphatis as well as the ammonium oxidizing bacteria belonging to the genus Nitrosomonas after PAC addition.

Biodegradation of trace pharmaceutical substances in wastewater by a membrane bioreactor

The biodegradation of selected pharmaceutical micropollutants, including two pharmaceuticals with argued biodegradation, was studied by a lab-scale membrane bioreactor. The reaction kinetics and affecting factors were also investigated in this paper. Clofibric acid (CA) with contradictive biodegradation reported was degraded almost completely at different hydraulic retention times (HRTs) after adaptation to microorganisms. The biodegradation of CA was disturbed at low pH operation, while the activity of microorganisms recovered again after pH adjustment to neutral condition. Ibuprofen (IBP) degraded under neutral and acidic conditions. Removals of IBP and CA were zero-order and first-order reactions under high and low initial concentrations, respectively. Carbamazepine and diclofenac were not degraded regardless of HRTs and pH.

5491190 Repulpable hot melt polymer/fatty acid compositions for fibrous products

Global population growth induces increased threat on drinking water resources. One way to address this environmental issue is to reuse water from wastewater treatment plant. The presence of pathogenic microorganisms and potentially toxic organic micropollutants does not allow a direct reuse of urban effluents. Membrane processes such reverse osmosis (RO) or nanofiltration (NF) can be considered to effectively eliminate these pollutants. The integration of membrane processes involves the production of concentrated retentates which require being disposed. To date, no treatment is set up to manage safely this pollution. This work focuses on the application of ozonation for the treatment of NF retentates in the framework of the wastewater reuse. Ozonation is a powerful oxidation process able to react and degrade a wide range of organic pollutants. Four pharmaceutical micropollutants were selected as target molecules: acetaminophen, carbamazepine, atenolol and diatrozic acid. This study highlighted that NF represents a viable alternative to the commonly used RO process ensuring high retention at much lower operating costs. Ozonation appears to be effective to degrade the most reactive pollutants toward molecular ozone but is limited for the reduction of refractory ozone pollutants due to the inhibition of the radical chain by the high content of organic matter in the retentates. The ozonation process appears to be a promising NF retentate treatment, but additional treatments after ozonation are required to lead to a zero liquid discharge treatment scheme.