André Lajeunesse

Determination of Basic Antidepressants and Their N-Desmethyl Metabolites in Raw Sewage and Wastewater Using Solid-Phase Extraction and Liquid Chromatography−Tandem Mass Spectrometry

A novel analytical method has been developed for the determination of six basic antidepressants (venlafaxine, sertraline, paroxetine, citalopram, amitriptyline, and fluoxetine) and four of their metabolites (O-desmethylvenlafaxine, desmethylsertraline, nortriptyline, and norfluoxetine) in raw sewage and roughly primary-treated wastewater. For analytical development purposes, two ion exchange solid-phase extraction cartridges were compared. Extracts were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with positive-mode electrospray (+ESI) and selected reaction monitoring transitions. The choice of a basic mobile phase significantly improved the instrumental sensitivity (by up to 14-fold for norfluoxetine) relative to common +ESI acidic mobile phases. In addition to the remarkable gain in sensitivity, negligible matrix effects were also observed in the raw sewage samples. Analyte recoveries ranged from 80 to 103% and effluent detection limits from 0.048 to 0.10 ng/L. Samples collected at the Montreal Wastewater Treatment Plant showed the unequivocal presence of all the target compounds at concentrations of 2-346 ng/L. The target antidepressants were also detected in samples taken from the effluent receiving waters (i.e., the St. Lawrence River) but at lower concentrations (0.41-69 ng/L). The highly sensitive proposed method constitutes one of the best means for monitoring the environmental occurrence of tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), and some of their metabolites.

Distribution of antidepressants and their metabolites in brook trout exposed to municipal wastewaters before and after ozone treatment--evidence of biological effects.

This study examined the tissues distribution of selected serotonin reuptake inhibitors (SSRIs) in brook trout exposed for 3 months to continuous flow-through primary-treated effluent before and after ozone treatment. A reliable analytical method was developed for the quantification of trace amounts of antidepressants in small tissue homogenate extracts. Levels of six antidepressants and four of their N-desmethyl metabolites were determined using liquid chromatography-tandem mass spectrometry. Significant amounts of the SSRIs were found in fish tissue-in decreasing order: liver>brain>muscle. Sertraline and its metabolite desmethylsertraline were the predominant substances observed in most tissues (0.04-10.3 ng g(-1)). However, less SSRIs (0.08-1.17 ng g(-1)) were bioaccumulated in the ozonated effluent. The early molecular effects of these SSRIs on the Na/K-dependent ATPase pump activity in brain synaptosomes where also investigated in vitro and in fish exposed to the municipal effluents. With respect to their potential biological effects, in vitro exposure to selected SSRIs induced a reduction of the brain Na/K-ATPase activity in synaptosomes in a dose-dependent manner. Results showed that Na/K-ATPase activity was readily inhibited by exposure to municipal effluent before and, to a lesser extent, after ozone treatment. Moreover, the Na/K-ATPase activity was significantly and negatively correlated with brain tissue concentrations of fluoxetine (r=-0.57; p<0.03), desmethylsertraline (r=-0.84; p<0.001), and sertraline (r=-0.82; p<0.001). The present study reveals that SSRIs are readily available in fish, biologically active and corroborates previous findings on the serotonergic properties of municipal effluents to aquatic organisms.

Toxic effects and bioaccumulation of carbamazepine evaluated by biomarkers measured in organisms of different trophic levels

The antiepileptic drug carbamazapine (CBZ) readily persists in sewage-water treatment plant wastewaters and finds its way into receiving water bodies. Our study sought to examine the bioaccumulation and toxicity of CBZ using an experimental aquatic trophic chain composed of the green alga, Pseudokirchneriella subcapitata, the crustacean, Thamnocephalus platyurus, and the cnidarian, Hydra attenuata. Bioaccumulation of CBZ was estimated by liquid chromatography-tandem mass spectrometry and revealed bioaccumulation factors of 2.2 and 12.6, respectively, in algae and crustaceans. No significant bioaccumulation was observed in H. attenuata. In T. platyurus, a strong stimulation of global heme oxidase (HO) (76%), and glutathione-S-transferase activity (130%) but a drastic inhibition of cytochrome P450 3A-like activity was found which suggests alteration of enzyme activity by CBZ. However, in the hydranth H. attenuata, an increase in both global cytochrome and cytochrome P450 3A-like activity was found, while GST activity was inhibited. Lipid peroxidation was reduced in T. platyurus and H. attenuata suggesting that redox activity of the lipophilic CBZ was at play. This study highlighted the processes of carbamazepine toxicity transfer between trophic levels in aquatic organisms.

Degradation of Selected Acidic and Neutral Pharmaceutical Products in a Primary-Treated Wastewater by Disinfection Processes

Anti-inflammatory and anti-convulsive drugs are being detected in measurable quantities in municipal wastewaters. Some of these emerging substances undergo major transformation at the sewage treatment plant after biological and chemical treatments. The degradation of pharmaceutical products from high-quality treated wastewaters by disinfection processes is well documented. However, the effect of disinfection processes on these products in physicochemical primary-treated municipal effluents remains to be investigated. Pilot projects using ozone, performic acid and UV-radiation disinfection processes were carried out at the Montreal wastewater treatment plant. Residues of pharmaceutical products like salicylic acid, clofibric acid, ibuprofen, naproxen, triclosan, carbamazepine, diclofenac, and 2-hydroxy-ibuprofen were found in the treated wastewaters before disinfection at concentrations ranging from 42 to 2556 ng/L. Most of these substances were eliminated at a rate greater than 50% at an ozone dose of 10 mg/L. Higher removal rates (as high as 70%) were observed when 20 mg/L of ozone was used. Removal rates for UV radiation, on the other hand, were often below 10% among the substances studied. Limited removal rate was observed after UV radiation for diclofenac and triclosan (25 and 40% efficiency, respectively). The irradiation used here (25 mJ/cm2) for bacterial treatment appeared, as previously reported, to be too low to cause the significant breakdown of many of the pharmaceutical substances contained in these wastewaters. Poor reduction efficiencies (< 8%) were observed with the performic acid treatment. Further investigations on analytical methodologies are therefore needed to assess the potential impact of degradation by-products on the environment and on human health.

Detection and confirmation of saxitoxin analogues in freshwater benthic Lyngbya wollei algae collected in the St. Lawrence River (Canada) by liquid chromatography-tandem mass spectrometry.

The presence of cyanotoxins in benthic Lyngbya wollei algae samples collected in a fluvial lake along the St. Lawrence River, Canada, was investigated using a multi-toxins method. Hydrophilic interaction liquid chromatography (HILIC) and reverse phased liquid chromatography (RPLC) were coupled to triple quadrupole mass spectrometry (LC-QqQMS) for quantification and to quadrupole-time of flight mass spectrometry (LC-QqTOFMS) for screening and confirmation. The presence of two saxitoxin analogues, LWTX-1 and LWTX-6, was confirmed in benthic Lyngbya wollei algae samples. Concentration of LWTX-1 was between 209±5 and 279±9 μg g(-1). No other targeted cyanotoxin (such as anatoxin-a, nodularin, microcystin-LR, microcystins-RR and saxitoxin) was found in the samples. The presence of LWTX-6 was observed by using a screening approach based on an in-house database of cyanotoxins, an algorithm of identification and high resolution mass spectrometry measurements on the precursor and product ions. This work demonstrates the need for more research on the fate of benthic cyanotoxins in aquatic ecosystems such the St. Lawrence River.

Determination of six anti-infectives in wastewater using tandem solid-phase extraction and liquid chromatography–tandem mass spectrometry

A rugged and specific method based on tandem solid-phase extraction and liquid chromatography-tandem mass spectrometry for the determination of anti-infectives in raw sewage and wastewater plant effluents was developed. Analyte recoveries from spiked effluents ranged from 68 to 104%. Two specific selected reaction monitoring transitions and their peak area ratios were used to avoid false positives and confirm the presence of the targeted substances. Detection limits allowed low nanogram per litre detection (0.3-22 ng L(-1)). The method was successfully applied to real samples from the Montréal wastewater treatment plant. All the studied anti-infectives were found in the wastewater samples in concentrations ranging from 39 to 276 ng L(-1). Mean flows of anti-infectives were estimated from effluent concentrations and it was found that large amounts (>118 g day(-1) up to 830 g day(-1)) are discharged in the receiving waters of the St Lawrence River.

Determination of acidic pharmaceutical products and carbamazepine in roughly primary-treated wastewater by solid-phase extraction and gas chromatography–tandem mass spectrometry

A gas chromatography–tandem mass spectrometry (GC–MS/MS) method has been developed for the determination of selected pharmaceutical residues (carbamazepine, salicylic acid, clofibric acid, ibuprofen, 2-hydroxy-ibuprofen, fenoprofen, naproxen, ketoprofen, diclofenac, and triclosan) in sewage influent and roughly primary-treated effluent. The method involved solid-phase extraction (SPE) with polymeric sorbents, and two SPE cartridges were compared for the extraction and elution of the targeted compounds in complex matrices. A successful chemical derivatization of carbamazepine and acidic compounds using N,O-bis(trimethylsilyl) trifluoroacetamide +10% trimethylchlorosilane is also described. The quantification limits of the analytical procedure ranged from 30 to 60 ng L−1 for 500 mL of wastewater. The best recovery rates (72–102%) in spiked effluent samples were obtained with Phenomenex Strata-X™ cartridges. Detection limits (S/N = 3) were estimated at between 1 and 18 ng L−1. The reported GC–MS/MS method significantly reduces the strong matrix effects encountered with more expensive LC-MS/MS techniques. Application of the developed method showed that most selected analytes were detected at concentrations ranging from low µg L−1 to trace level ng L−1 in Montreals wastewater treatment plant effluent and influent, as well as in the receiving waters at more than 8 km downstream of the effluent outfall. The rugged alternative analytical method is suitable for the simultaneous analysis of carbamazepine and pharmaceutical acidic residues in wastewater samples from influents and effluents that have undergone rough primary treatment.

Ozone oxidation of antidepressants in wastewater –Treatment evaluation and characterization of new by-products by LC-QToFMS

BackgroundThe fate of 14 antidepressants along with their respective N-desmethyl metabolites and the anticonvulsive drug carbamazepine was examined in a primary sewage treatment plant (STP) and following advanced treatments with ozone (O3). The concentrations of each pharmaceutical compound were determined in raw sewage, effluent and sewage sludge samples by LC-MS/MS analysis. The occurrence of antidepressant by-products formed in treated effluent after ozonation was also investigated.ResultsCurrent primary treatments using physical and chemical processes removed little of the compounds (mean removal efficiency: 19%). Experimental sorption coefficients (Kd) of each studied compounds were also calculated. Sorption of venlafaxine, desmethylvenlafaxine, and carbamazepine on sludge was assumed to be negligible (log Kd ≤ 2), but higher sorption behavior can be expected for sertraline (log Kd ≥ 4). Ozonation treatment with O3 (5 mg/L) led to a satisfactory mean removal efficiency of 88% of the compounds. Screening of the final ozone-treated effluent samples by high resolution-mass spectrometry (LC-QqToFMS) did confirm the presence of related N-oxide by-products.ConclusionEffluent ozonation led to higher mean removal efficiencies than current primary treatment, and therefore represented a promising strategy for the elimination of antidepressants in urban wastewaters. However, the use of O3 produced by-products with unknown toxicity.

Persistence and fate of highly soluble pharmaceutical products in various types of municipal wastewater treatment plants.

Municipal effluents are important source of contaminants including many socalled Pharmaceutical and Personal Care Products (PPCPs) substances, whose potential impacts on the receiving environment are poorly understood. New emerging substances, in the form of pharmaceutical drugs like antibiotics, antiinflammatory, and anti-convulsive, are now being frequently measured in these wastewaters. While PPCPs substances undergo major transformation at the treatment plant and again in the receiving waters, their bioavailability and toxicity may be modified considerably. The influence of different wastewater treatment processes on pharmaceutical products was investigated. Pharmaceutical substances such as clofibric acid, carbamazepine, diclofenac, ibuprofen and naproxen were found in the Montreal physicochemical primarytreated effluents at concentrations ranging from 13 to 3522 ng/L. Most of the substances were eliminated at a rate lower than 10%. Biological treatments (aerobic conditions) with activated sludge resulted in much better removal rates (> 50%) for those studied substances. Interestingly, this type of process showed some selectivity with respect to the size and polarity of the removed substances; the smallest and most polar substances were removed at better rates, while the persistent carbamazepine (273-483 ng/L) and diclofenac (52-68 ng/L) were poorly removed. In the case of treatment by aerated lagoons, the most abundant substances were hydroxy-ibuprofen (339-3938 ng/L), naproxen (16-763 n/L) and carbamazepine (164-425 ng/L). To assess the impacts of all these contaminants on the environment and human health, we need to better understand the chemical and physical transformations occurring at the treatment plant and in the receiving waters.

Determination of carbamazepine in aquatic organisms by liquid–liquid extraction and liquid chromatography-tandem mass spectrometry

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for the determination of carbamazepine in microgram quantities of crustacean Thamnocephalus platyurus and the algae Pseudokirchneriella subcapitata at the ng L(-1) level. This fully validated method applied to a bioaccumulation study was found suitable for the detection of carbamazepine in small aquatic tissues.