Removal of Zwitterionic PFAS by MXenes: Comparisons with Anionic, Nonionic, and PFAS-Specific Resins.

Zwitterionic per- and polyfluoroalkyl substances are increasingly detected in aquatic environments. The magnitude of their concentration and increased frequency of detection worldwide raise questions on their presence in drinking water and associated health risk. Scientific knowledge on the identification of treatment technologies to effectively capture such zwitterionic PFAS from contaminated water sources remains largely unknown. In this study, we investigated the application of anionic organic scavenger ion exchange (IX) resins (A860), nonionic IX resins (XAD 4 and XAD 7), PFAS-specific resins (A694 and A592), and Ti3C2 MXenes (novel two-dimensional metal carbides) for the removal of select fluorotelomer zwitterionic PFAS from natural waters. The cumulative removal of zwitterionic PFAS at pH ∼ 7 follows the order: Ti3C2 MXenes > A694 > A592 > A860 > XAD 4 ∼ XAD 7. Ti3C2 MXenes were able to capture >75% of the total influent zwitterionic PFAS and the performance remained consistent in natural and synthetic water. Ti3C2 MXenes also exhibited efficient regeneration (>90% recovery) with 0.4 M Na2SO3 solution, while the regeneration efficacy of other IX resins generally remained below 20%. Treatment with ∼180 J/cm2 UV dosage in the 0.4 M Na2SO3 regenerant brine solution yielded >99.9% reduction in the zwitterionic PFAS concentration indicating that UV-sulfite systems exhibit promising potential for the treatment of zwitterionic PFAS concentrates.

Occurrence and Distribution of Per- and Polyfluoroalkyl Substances in Tianjin, China: The Contribution of Emerging and Unknown Analogues.

Tianjin, located in Bohai Bay, China, constitutes a relevant study area to investigate emerging per- and polyfluoroalkyl substances (PFASs) due to its high population density, clustering of chemical and aircraft industries, as well as international airports, harbors, and oil rigs. In this study, 53 anionic, zwitterionic, and cationic PFASs were monitored in river surface water, groundwater, seawater, and sediments in this area (overall n = 226). 6:2 chlorinated polyfluorinated ether sulfonic acid (Cl-PFESA), perfluorooctanoic acid, and perfluorooctane sulfonic acid were generally the predominant PFASs. 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB) was also widespread (occurrence >86%), with the highest concentration (1300 ng/L) detected at contamination hot spots impacted by wastewater effluents. The aqueous film-forming foam (AFFF)-related PFASs with sulfonamide betaine, amine oxide, amine, or quaternary ammonium moieties are also reported for the first time in river water and seawater samples. Fifteen classes of infrequently reported PFASs, including n:2 FTABs and n:2 fluorotelomer sulfonamide amines, hydrogen-substituted PFESA homologues, and p-perfluorous nonenoxybenzenesulfonate (OBS), were also identified in the water and sediment samples using suspect screening. Field-derived sediment-water distribution coefficients (Kd) of these emerging PFASs are provided for the first time, confirming that cationic and zwitterionic PFASs tend to be strongly associated with sediments.

Precipitation effects on parasite, indicator bacteria, and wastewater micropollutant loads from a water resource recovery facility influent and effluent.

The variability of fecal microorganisms and wastewater micropollutants (WWMPs) loads in relation to influent flow rates was evaluated for a water resource recovery facility (WRRF) in support of a vulnerability assessment of a drinking water source. Incomplete treatment and bypass discharges often occur following intense precipitation events that represent conditions that deviate from normal operation. Parasites, fecal indicator bacteria, and WWMPs concentrations and flow rate were measured at the WRRF influent and effluent during dry and wet weather periods. Influent concentrations were measured to characterize potential bypass concentrations that occur during wet weather. Maximum influent Giardia and C. perfringens loads and maximum effluent Escherichia coli and C. perfringens loads were observed during wet weather. Influent median loads of Cryptosporidium and Giardia were 6.8 log oocysts/day and 7.9 log cysts/day per 1,000 people. Effluent median loads were 3.9 log oocysts/day and 6.3 log cysts/day per 1,000 people. High loads of microbial contaminants can occur during WRRF bypasses following wet weather and increase with increasing flow rates; thus, short-term infrequent events such as bypasses should be considered in vulnerability assessments of drinking water sources in addition to the increased effluent loads during normal operation following wet weather.

Adequate Reducing Conditions Enable Conjugation of Oxidized Peptides to Polymers by One-Pot Thiol Click Chemistry.

Thiol(-click) chemistry has been extensively investigated to conjugate (bio)molecules to polymers. Handling of cysteine-containing molecules may however be cumbersome, especially in the case of fast-oxidizing coiled-coil-forming peptides. In the present study, we investigated the practicality of a one-pot process to concomitantly reduce and conjugate an oxidized peptide to a polymer. Three thiol-based conjugation chemistries (vinyl sulfone (VS), maleimide, and pyridyldithiol) were assayed along with three reducing agents (tris(2-carboxyethyl)phosphine (TCEP), dithiothreitol, and ß-mercaptoethanol). Seven out of the nine possible combinations significantly enhanced the conjugation yield, provided that an adequate concentration of reductant was used. Among them, the coincubation of an oxidized peptide with TCEP and a VS-modified polymer displayed the highest level of conjugation. Our results also provide insights into two topics that currently lack consensus: TCEP is stable in 10 mM phosphate buffered saline and it reacts with thiol-alkylating agents at submillimolar concentrations, and thus should be carefully used in order to avoid interference with thiol-based conjugation reactions.

Evaluation of on-line concentration coupled to liquid chromatography tandem mass spectrometry for the quantification of neonicotinoids and fipronil in surface water and tap water.

A study was initiated to investigate a fast and reliable method for the determination of selected systemic insecticides in water matrixes and to evaluate potential sources of bias in their analysis. Acetamiprid, clothianidin, desnitro-imidacloprid, dinotefuran, fipronil, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam were amenable to analysis via on-line sample enrichment hyphenated to ultra-high-performance liquid chromatography tandem mass spectrometry. The selection of on-line solid-phase extraction parameters was dictated by a multicriterion desirability approach. A 2-mL on-line injection volume with a 1500 µL min-1 loading flow rate met the objectives sought in terms of chromatographic requirements, extraction efficiency, sensitivity, and precision. A total analysis time of 8 min per sample was obtained with method limits of detection in the range of 0.1-5 ng L-1 for the scope of targeted analytes. Automation at the sample concentration step yielded intraday and interday precisions in the range of 1-23 and 2-26%, respectively. Factors that could affect the whole method accuracy were further evaluated in matrix-specific experiments. The impact of the initial filtration step on analyte recovery was evaluated in ultra-pure water, tap water, and surface water. Out of the nine membranes tested, glass fiber filters and polyester filters appeared as the most appropriate materials. Sample storage stability was also investigated across the three matrix types; the targeted analytes displayed suitable stability during 28 days at either 4 °C or - 20 °C, with little deviations (± 10%) with respect to the initial T0 concentration. Method applicability was demonstrated in a range of tap water and surface water samples from the province of Québec, Canada. Results from the present survey indicated a predominance of thiamethoxam (< 0.5-10 and 3-61 ng L-1 in tap water and river water, respectively), clothianidin (< 0.5-6 and 2-88 ng L-1 in tap water and river water, respectively), and imidacloprid (< 0.1-1 and 0.8-38 ng L-1 in tap water and river water, respectively) among the targeted analytes. Graphical abstract ᅟ Development of solid-phase extraction coupled on-line to UHPLC-MS/MS for the rapid screening of systemic insecticides in water.

Environmental Occurrence of Perfluoroalkyl Acids and Novel Fluorotelomer Surfactants in the Freshwater Fish Catostomus commersonii and Sediments Following Firefighting Foam Deployment at the Lac-Mégantic Railway Accident.

On July 6th 2013, an unmanned train laden with almost 8 million liters of crude oil careened off the rails downtown Lac-Mégantic (Québec, Canada). In the aftermath of the derailment accident, the emergency response entailed the deployment of 33 000 L of aqueous film forming foam (AFFF) concentrate that contained proprietary fluorosurfactants. The present study examines the environmental occurrence of perfluoroalkyl acids (PFAAs) and newly identified per and polyfluoroalkyl substances (PFASs) in the benthic fish white sucker (Catostomus commersonii) and sediments from Lake Mégantic and Chaudière River. In sediments, PFAAs displayed relatively low concentrations (∑PFAAs = 0.06-0.5 ng g-1 dw) while the sum of fluorotelomer-based PFASs was in the range < LOD-6.2 ng g-1 dw. Notably, fluorotelomer sulfonamide betaines (8:2-FTAB and 10:2-FTAB), fluorotelomer betaines (9:3-FTB, 11:3-FTB and 9:1:2 FTB) and 6:2 fluorotelomer sulfonate (6:2-FTSA) were ubiquitously identified in the sediment samples surveyed. Levels of PFAAs remained moderate in fish muscle (e.g. , PFOS: 0.28-2.1 ng g-1 wet-weight), with little or no differences when comparing 2013 or 2014 fish samples with 2011 archived samples. In contrast, n:2-FTSAs emerged in the immediate weeks or months that followed the accident, as did several betaine-based PFASs (8:2-FTAB, 10:2-FTAB, 9:3-FTB, 11:3-FTB, 7:1:2 FTB and 9:1:2 FTB), observed for the first time in situ. Fluorotelomer thioether amido sulfonate (10:2-FTSAS) and fluorotelomer sulfoxide amido sulfonate (10:2-FTSAS-sulfoxide) were also occasionally reported after the AFFF spill. With time, levels of betaine-based PFASs gradually decreased in fish, possibly indicating attenuation by biodegradation of the fluorine-free moiety, supported by the observation of likely metabolites such as n:3-fluorotelomer carboxylates and n:2-fluorotelomer sulfonamides.

Phytoremediation of groundwater contaminated with pesticides using short-rotation willow crops: A case study of an apple orchard.

The occurrence of pesticides in groundwater represents an important health issue, notably for population whose drinking water supply source is located in agricultural areas. However, few solutions have been considered with regard to this issue. We tested the efficacy of a vegetal filtering system made of shrub willows planted at a high density (16,000 plants ha(-1)) to filter or degrade pesticides found in the groundwater flowing out of an apple orchard. Ethylene urea (EU), ethylene thiourea (ETU), tetrahydrophthalimide (THPI), atrazine, and desethylatrazine were monitored in the soil solution in willow and control plots over one growing season. ETU and atrazine concentrations were lower in the willow plots relative to the control plots, whereas desethylatrazine concentration was higher in the willow plots. No significant difference was detected for EU and THPI. Furthermore, pesticide concentrations displayed complex temporal patterns. These results suggest that willow filter systems can filter or degrade pesticides, notably ETU and atrazine, and could be used for phytoremediation purposes. Yet, this potential remains to be quantified with further studies using experimental settings allowing more estimation in time and space.

Biodegradation of multiple microcystins and cylindrospermopsin in clarifier sludge and a drinking water source: Effects of particulate attached bacteria and phycocyanin.

The effects of particulate attached bacteria (PAB) and phycocyanin on the simultaneous biodegradation of a mixture of microcystin-LR, YR, LY, LW, LF and cylindrospermopsin (CYN) was assessed in clarifier sludge of a drinking water treatment plant (DWTP) and in a drinking water source. The biomass from lake water and clarifier sludge was able to degrade all microcystins (MCs) at initial concentrations of 10µgL(-1) with pseudo-first order reaction half-lives ranging from 2.3 to 8.8 days. CYN was degraded only in the sludge with a biodegradation rate of 1.0×10(-1)d(-1) and a half-life of 6.0 days. This is the first study reporting multiple MCs and CYN biodegradation in the coagulation-flocculation sludge of a DWTP. The removal of PAB from the lake water and the sludge prolonged the lag time substantially, such that no biodegradation of MCLY, LW and LF was observed within 24 days. Biodegradation rates were shown to increase in the presence of C-phycocyanin as a supplementary carbon source for indigenous bacteria, a cyanobacterial product that accompanies cyanotoxins during cyanobacteria blooms. MCs in mixtures degraded more slowly (or not at all) than if they were degraded individually, an important outcome as MCs in the environment are often present in mixtures. The results from this study showed that the majority of the bacterial biomass responsible for the biodegradation of cyanotoxins is associated with particles or biological flocs and there is a potential for extreme accumulation of cyanotoxins within the DWTP during a transient bloom.

A new protocol for the analysis of pharmaceuticals, pesticides, and hormones in sediments and suspended particulate matter from rivers and municipal wastewaters.

We developed a protocol to quantify 12 emerging contaminants (ECs) (pharmaceuticals and hormones) and pesticides extracted from suspended particulate matter (SPM) of river water and municipal wastewaters samples as well as river sediments. The separation of suspended solids was realized using filtration of water samples. We tested a series of six different filter types. The effect of filtration on the concentrations of dissolved contaminants was evaluated to minimize losses of target compounds. The river sediment samples were lyophilized, and both SPM and sediment samples were subjected to ultrasonic extraction combined with C18 cartridge clean-up. Quantifications were realized using mass spectrometry. The method recoveries of all compounds ranged from 38 to 112 % in all studied matrices; poorer recoveries were achieved for sulfamethoxazole and diclofenac (as low as 38 %), whereas the recoveries for all other compounds in the wastewater treatment plant (WWTP) samples were between 68 and 111 %. The detection limits in sediments and SPM from river samples for the 12 analytes varied from 0.7 to 9.4 ng g(-1) and from 21 to 92 ng g(-1) for WWTP SPM samples. All targeted ECs were detected with concentrations ranging from 3 to 5,440 ng g(-1) in the studied matrices with the highest concentrations observed in WWTP SPM samples. A significant portion of the contaminants in a water sample is clearly associated with the suspended particulates. Optimization of water-treatment processes and environmental fate must absolutely consider the fraction of contaminants that is particulate-bound if one hopes to have a reasonable mass balance.

ß-D-glucuronidase activity triggered monitoring of fecal contamination using microbial and chemical source tracking markers at drinking water intakes.

Intense rainfall and snowmelt events may affect the safety of drinking water, as large quantities of fecal material can be discharged from storm or sewage overflows or washed from the catchment into drinking water sources. This study used ß-d-glucuronidase activity (GLUC) with microbial source tracking (MST) markers: human, bovine, porcine mitochondrial DNA markers (mtDNA) and human-associated Bacteroidales HF183 and chemical source tracking (CST) markers including caffeine, carbamazepine, theophylline and acetaminophen, pathogens (Giardia, Cryptosporidium, adenovirus, rotavirus and enterovirus), water quality indicators (Escherichia coli, turbidity) and hydrometeorological data (flowrate, precipitation) to assess the vulnerability of 3 drinking water intakes (DWIs) and identify sources of fecal contamination. Water samples were collected under baseline, snow and rain events conditions in urban and agricultural catchments (Québec, Canada). Dynamics of E. coli, HF183 and WWMPs were similar during contamination events, and concentrations generally varied over 1 order of magnitude during each event. Elevated human-associated marker levels during events demonstrated that urban DWIs were impacted by recent contamination from an upstream municipal water resource recovery facility (WRRF). In the agricultural catchment, mixed fecal pollution was observed with the occurrences and increases of enteric viruses, human bovine and porcine mtDNA during peak contaminating events. Bovine mtDNA qPCR concentrations were indicative of runoff of cattle-derived fecal pollutants to the DWI from diffuse sources following rain events. This study demonstrated that the suitability of a given MST or CST indicator depend on river and catchment characteristics. The sampling strategy using continuous online GLUC activity coupled with MST and CST markers analysis was a more reliable source indicator than turbidity to identify peak events at drinking water intakes.

Cyanotoxins dissipation in soil: Evidence from microcosm assays.

Cyanobacteria proliferate in warm, nutrient-rich environments, and release cyanotoxins into natural waters. If cyanotoxin-contaminated water is used to irrigate agricultural crops, this could expose humans and other biota to cyanotoxins. However, cyanotoxins may be degraded by the diverse microbial consortia, be adsorbed or otherwise dissipate in agricultural soil. This study investigates the disappearance and transformation of 9 cyanotoxins in controlled soil microcosms after 28 d. Six soil types were exposed to factorial combinations of light, redox conditions and microbial activity that influenced the recovery of anabaenopeptin-A (AP-A), anabaenopeptin-B (AP-B), anatoxin-a (ATX-a), cylindrospermopsin (CYN), and the microcystin (MC) congeners -LR, -LA, -LY, -LW, and -LF. Cyanotoxins estimated half-lives were from hours to several months, depending on the compound and soil conditions. Cyanotoxins were eliminated via biological reactions in aerobic and anaerobic soils, although anaerobic conditions accelerated the biological dissipation of ATX-a, CYN and APs. ATX-a was sensitive to photolytic degradation, but CYN, and MCs were not reduced through photochemical transformation. MC-LR and -LA were recovered after exposure to light, redox conditions and low microbial activity, suggesting that they persisted in extractable forms, compared to other cyanotoxins in soil. Cyanotoxin degradation products were identified using high-resolution mass spectrometry, revealing their potential degradation pathways in soil.

Effects of macrophyte species and biochar on the performance of treatment wetlands for the removal of glyphosate from agricultural runoff.

Glyphosate is the most widely used herbicide in the world, and consequently has polluted numerous water bodies through agricultural runoff. Treatment wetlands (TWs) have shown great promise for mitigating such pesticide contamination. The objectives of our study were to determine the effects of adding biochar to subsurface flow TW substrate, and to evaluate the performance of three North American macrophyte species (Phragmites australis subsp. americanus, Scirpus cyperinus and Sporobolus michauxianus) for removal of glyphosate. A synthetic agricultural runoff comprising 50 µg/L of glyphosate was applied to water-saturated TW mesocosms with mature vegetation during a 5.5-week period. Average removal efficiency, calculated on a mass balance basis, reached 78 and 82% for mesocosms with biochar (without and with plants, respectively), and 54 to 76% for those with macrophytes. Sporobolus michauxianus showed a lower evapotranspiration rate and less anoxic conditions in the lower part of the substrate, which resulted in lower overall removal performance. Aminomethylphosphonic acid (AMPA), the main toxic metabolite of glyphosate, was detected in all mesocosms, but at higher levels in planted ones. Results show that both the sorption capacity of biochar and the biodegradation processes associated with macrophytes contribute to glyphosate removal in TWs. Additionally, our results suggest that species selection is important to enhance favorable conditions and maximize removal of targeted pollutants.

Bioaccumulation and trophic magnification of emerging and legacy per- and polyfluoroalkyl substances (PFAS) in a St. Lawrence River food web.

Research on per- and polyfluoroalkyl substances (PFAS) in freshwater ecosystems has focused primarily on legacy compounds and little is still known on the presence of emerging PFAS. Here, we investigated the occurrence of 60 anionic, zwitterionic, and cationic PFAS in a food web of the St. Lawrence River (Quebec, Canada) near a major metropolitan area. Water, sediments, aquatic vegetation, invertebrates, and 14 fish species were targeted for analysis. Levels of perfluorobutanoic acid (PFBA) in river water exceeded those of perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS), and a zwitterionic betaine was observed for the first time in the St. Lawrence River. The highest mean PFAS concentrations were observed for the benthopelagic top predator Smallmouth bass (Micropterus dolomieu, Σ60PFAS âˆ¼ 92 ± 34 ng/g wet weight whole-body) and the lowest for aquatic plants (0.52-2.3 ng/g). Up to 33 PFAS were detected in biotic samples, with frequent occurrences of emerging PFAS such as perfluorobutane sulfonamide (FBSA) and perfluoroethyl cyclohexane sulfonate (PFECHS), while targeted ether-PFAS all remained undetected. PFOS and long-chain perfluorocarboxylates (C10-C13 PFCAs) dominated the contamination profiles in biota except for insects where PFBA was predominant. Gammarids, molluscs, and insects also had frequent detections of PFOA and fluorotelomer sulfonates, an important distinction with fish and presumably due to different metabolism. Based on bioaccumulation factors >5000 and trophic magnification factors >1, long-chain (C10-C13) PFCAs, PFOS, perfluorodecane sulfonate, and perfluorooctane sulfonamide qualified as very bioaccumulative and biomagnifying. Newly monitored PFAS such as FBSA and PFECHS were biomagnified but moderately bioaccumulative, while PFOA was biodiluted.

Quantitative screening for cyanotoxins in soil and groundwater of agricultural watersheds in Quebec, Canada.

Cyanotoxins, as secondary metabolites of cyanobacteria, are highly toxic to humans, animals and plants. Cyanobacterial blooms are 'hot spots' for cyanotoxin production, but we hypothesized that cyanotoxins will be present in multiple ecological compartments of agricultural watersheds. We detected cyanotoxins in the vadose zone (soil and drainage water from the soil profile) and in groundwater used as a drinking water source from agricultural watersheds. Cyanotoxins detection was confirmed with enzyme-linked immunosorbent assay kits and ultra-high liquid chromatography with tandem mass spectrometry. This work confirms that cyanotoxins exist outside of freshwater lakes, based on detection of microcystins in the vadose zone and in drinking water sourced from groundwater in agricultural watersheds. This suggests that cyanotoxins may be transferred from cyanobacterial blooms in lakes to groundwater through normal hydrologic processes. Public health authorities should be alerted to cyanotoxins in drinking water supplies and proper monitoring and treatment protocols should be implemented to protect citizens from this potential health hazard.

A quantitative UHPLC-MS/MS method for the growth hormone-releasing peptide-6 determination in complex biological matrices and transdermal formulations.

Growth hormone-releasing peptide-6 (GHRP-6) is part of a group of small synthetic peptides with potent GH-releasing activity that have gained attention in the last two decades by virtue of their cyto- and cardioprotective effects. Despite numerous preclinical studies highlighting the potential cardiovascular benefits of GHRP-6, confirmation of clinical efficacy is still awaited. Recent advances in transdermal drug delivery systems have been made to address challenges related to the poor skin permeation rate of peptides by using pain-free microneedle (MN) devices. Accordingly, highly sensitive and validated analytical methods are required for the potential clinical translation of MN-based peptides. The ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) methods developed in this study aimed to quantify GHRP-6 in biological matrices (plasma, skin) and dissolving polymeric MNs. UHPLC/MS-MS method detection limits of 0.1, 1.1, 0.9 and 1.5 ng/mL were achieved in neat solution, plasma, MN polymer solution, and skin matrices, respectively. Method validation also involved assessment of precision, accuracy, limits of quantification, linearity of matched calibration curves (R2 > 0.990), extraction recovery, matrix effect, stability studies, selectivity, and carry-over effect. Additionally, quality control samples were analyzed at three concentration levels to determine recovery (85-109%) and accuracy/bias (3.2-14.7%). Intra- and inter-day precision were within the range of acceptance (RSDs of 3.0-13.9% and 0.4-14.5%, respectively). The validity and applicability of such methods were successfully demonstrated for transdermal GHRP-6 delivery using GHRP-6-loaded MN patches applied to pig skin.

Degradation and defluorination of 6:2 fluorotelomer sulfonamidoalkyl betaine and 6:2 fluorotelomer sulfonate by Gordonia sp. strain NB4-1Y under sulfur-limiting conditions.

6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB) is a major component of aqueous film-forming foams (AFFFs) used for firefighting and is frequently detected, along with one of its suspected transformation products, 6:2 fluorotelomer sulfonate (6:2 FTSA), in terrestrial and aquatic ecosystems impacted by AFFF usage. Biochemical processes underlying bacterial biodegradation of these compounds remain poorly understood due to a lack of pure culture studies. Here, we characterized the water-soluble and volatile breakdown products of 6:2 FTSA and 6:2 FTAB produced using Gordonia sp. strain NB4-1Y cultures over seven days under sulfur-limited conditions. After 168 h, 99.9% of 60 µM 6:2 FTSA was degraded into ten major breakdown products, with a mol% recovery of 88.2, while 70.4% of 60 µM 6:2 FTAB was degraded into ten major breakdown products, with a mol% recovery of 84.7. NB4-1Y uses two pathways for 6:2 FTSA metabolism, with 55 mol% of breakdown products assigned to a major pathway and <1.0 mol% assigned to a minor pathway. This work indicates that rapid transformation of 6:2 FTSA and 6:2 FTAB can be achieved under controlled conditions and improves the bacterial metabolism of these compounds.

Temporal variability of parasites, bacterial indicators, and wastewater micropollutants in a water resource recovery facility under various weather conditions.

Wastewater discharges lead to the deterioration of receiving waters through treated effluents and by-passes, combined and sanitary sewer overflows, and cross-connections to storm sewers. The influence of weather conditions on fecal indicator bacteria, pathogens and wastewater micropollutants on raw and treated sewage concentrations has not been extensively characterized. However, such data are needed to understand the effects of by-pass discharges and incomplete treatment on receiving waters. A water resource recovery facility was monitored for pathogenic parasites (Cryptosporidium oocysts, Giardia cysts), fecal indicator bacteria (Escherichia coli, Clostridium perfringens), and wastewater micropollutants (caffeine, carbamazepine, 2-hydroxycarbamazepine, acesulfame, sucralose, and aspartame) during 6 events under different weather conditions (snowmelt and trace to 32 mm 2-day cumulative precipitation). Greater intra- and inter-event variability was observed for Giardia, E. coli and C. perfringens than for studied WWMPs. Even with the addition of inflow and infiltration, daily variations dominated concentration trends. Thus, afternoon and early evening were identified as critical times with regards to high concentrations and flows for potential by-pass discharges. Peak concentrations of Giardia were observed during the June wet weather event (1010 cysts/L), with the highest flowrates relative to the mean monthly flowrate. Overall, Giardia, E. coli and C. perfringens concentrations were positively correlated with flowrate (R > 0.32, p < 0.05). In raw sewage samples collected under high precipitation conditions, caffeine, carbamazepine and its metabolite 2-OH-carbamazepine were significantly correlated (p < 0.05) with Giardia, E. coli, and C. perfringens demonstrating that they are useful markers for untreated sewage discharges. Data from the study are needed for estimating peak concentrations discharged from wastewater sources in relation to precipitation or snowmelt events.

Zwitterionic, cationic, and anionic perfluoroalkyl and polyfluoroalkyl substances integrated into total oxidizable precursor assay of contaminated groundwater.

The total oxidizable precursor (TOP) assay can be useful for integrating precursors to perfluoroalkyl acids (pre-PFAAs) into the assessment of sites contaminated by per- and polyfluoroalkyl substances (PFAS). Current research gaps include risks of instrumental matrix effects due to the complexity of post-oxidation extracts, potential reproducibility issues during TOP itself, and limited information for zwitterionic and cationic pre-PFAAs. We first investigated a suitable method for the analysis of groundwater samples, using liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). Initial sample pre-treatment through filtration could affect the dissolved PFAS concentrations and was therefore avoided. Amending the postoxidation samples with methanol allowed for improved precision and low instrumental matrix effects. We also documented the oxidation yields of 23 anionic, neutral, zwitterionic, and cationic precursor compounds of PFAAs. These precursor compounds were amenable to TOP conversion. The total oxidative yield of 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB), for instance, was 80 mol%, with C3-C5 PFCAs as major oxidation products (minor: C6-C7 PFCAs). The method was applied to determine a wide range of PFAS (n = 41) without oxidation as well as ΔPFCA via persulfate oxidation in AFFF-impacted groundwater samples from fire-equipment testing sites in Ontario and Newfoundland, Canada. Summed PFAS concentrations as high as 5 mg L-1 were reported before oxidation, and post-oxidation increases of PFCAs up to + 2300% were observed. A significant contribution of increases in individual PFCAs was attributed to precursors such as 6:2 FTAB, fluorotelomer sulfonates (6:2 FtS, 8:2 FtS), perfluorooctane sulfonamidoalkyl amine (PFOSAm), and perfluorohexane sulfonamide (FHxSA) at the active firefighting training site.

Seasonal variations of steroid hormones released by wastewater treatment plants to river water and sediments: Distribution between particulate and dissolved phases.

Extensive environmental monitoring was conducted in an urban river impacted by multiple combined sewer overflows (CSOs) and wastewater treatment plant (WWTP) discharge points. Temporal and spatial distributions of dissolved and particulate steroids (progesterone (Prog), testosterone (Testo), medroxyprogesterone (MDRXY-Prog), levonorgestrel (Levo), norethindrone (Nore), estrone (E1), estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2)) were investigated in sewage, WWTP effluents, receiving river water and sediments, and in drinking water plant (DWP) intakes. Steroids were detected in both dissolved and particulate phases with mean concentrations from 21ngL-1 to 389ngL-1 in raw sewage and from 10ngL-1 to 296ngL-1 in treated wastewater. The particle-associated steroids represented 0-82% of their total concentration as some steroids like E1 and E3 were detected only in the dissolved phase while MDRXY-Prog (81%), Nore (71%), and EE2 (>75%) were primarily detected in the particulate phase. Particle-associated steroids were detected in spring samples from river water with mean concentrations ranging from 5.4ngL-1 to 35.7ngL-1 compare to 3ngL-1 to 6.8ngL-1 in summer samples. Levels of particle-associated Testo, Nore, E2 and Levo in DWP intakes (406.2-13,149.1ngg-1) were similar to those found in raw sewage (336.6-7628.8ngg-1), indicating their persistence in the suspended phase from discharge points. Total steroids measured in sediments were in the range of 7-1213ngg-1, 5-25ngg-1, and 22-226ngg-1 in autumn, spring, and summer, respectively. Our findings confirm the presence and seasonal variation of a mixture of particle-associated steroids in drinking water sources. The presence of high concentrations of a mixture of particle-associated steroids in DWP intakes highlight the need for highly effective particle-removal processes to eliminate these recalcitrant compounds during drinking water production. Finally, the detected concentrations raise concerns about their potential environmental effects.

Quantification of peptides in human synovial fluid using liquid chromatography-tandem mass spectrometry.

A method to explore the stability of two anti-inflammatory peptides in human synovial fluid (HSF) has been developed and validated using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The two peptides are BQ123 Cyclo(-D-Trp-D-Asp-L-Pro-D-Val-L-Leu, Mw = 610.7) and R-954 (AcOrn[Oic2, (αMe)Phe5, DßNal7, Ile8]desArg9-bradykinin, Mw = 1194.4). Human synovial fluid samples were analyzed after a protein precipitation step with acetonitrile and dilution with mobile phase. DMSO was used as anti-adsorptive agent. We used an octyl silane column with formic acid (0.1%, v/v) in water as the aqueous mobile phase and acetonitrile isopropanol-formic acid (20:80, 0.1 v/v) as the organic mobile phase and 0.7 mL/min flow rate. The peptides CY-771 and pepstatin A were used as internal standards. Selective detection was performed by tandem mass spectrometry with a heated electrospray source (HESI), operated in positive ionization mode and in selected reaction monitoring acquisition (SRM). The method limit of quantification (injection volume = 10 µL) was 0.17 ng and 1.2 ng, corresponding to 28 and 102 nmol L-1 for BQ123 and R-954 respectively in human synovial fluid. Calibration curves obtained using matrix-matched calibration standards and internal standard were linear from 20 to 1000 nmol L-1. Precision values (%R.S.D.) were ≤ 14% in the entire linear range. Accuracy measured at a low and a high concentration level ranged from 93.1% to 102%. The recoveries (at 800 nmol L-1) were 96.4% for BQ123 and 102.0% for R-954. The method was successfully applied to follow the degradation kinetics of both peptides in human synovial fluid from arthritic patients during 72 h.