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A rapid on-line solid-phase extraction liquid chromatography high-resolution mass spectrometry (on-line SPE-LC-HRMS) method was developed to analyze 11 ultra-short and short-chain PFAS in surface water. Analytical optimization involved screening 7 chromatographic columns and 5 on-line SPE columns, as well as evaluating SPE loading conditions, filters, sample acidification, chromatographic mobile phases, and SPE loading mobile phases. The optimized method was then applied to 44 river water samples collected in Eastern Canada, including sites near airports with fire-training areas. Among the 11 targeted PFAS, the most frequently detected were trifluoroacetic acid (TFA, 4.6-220 ng/L), perfluorobutanoic acid (PFBA, 0.85-33 ng/L), perfluoropentanoic acid (PFPeA, 1.2-2100 ng/L), trifluoromethane sulfonic acid (TMS, 0.01-4.3 ng/L), and perfluorobutane sulfonic acid (PFBS, 0.07-450 ng/L). Levels of C3-C5 perfluoroalkyl carboxylic acids (PFCAs), C2-C4 perfluoroalkyl sulfonates (PFSAs) and n:3 polyfluoroalkyl acids (n = 2,3; n:3 acids) were significantly higher in water bodies near fire-training area sites compared with rivers in urban areas. In contrast, TFA, TMS, and 1:3 acid were not significantly elevated, likely reflecting atmospheric deposition or other diffuse sources for these compounds. Nontarget and suspect screening analysis revealed an abundance of other ultra-short and short-chain PFAS in AFFF-impacted water bodies. Perfluoroalkyl sulfonamides (FASA, C2, C3, and C5), perfluoroalkyl sulfonamide propanoic acids (FASA-PrA, C1-C2) and n:3 acids (n = 1, 4, and 5) were detected for the first time in environmental surface waters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

A reconnaissance survey was undertaken to evaluate the occurrence and risks of 27 pharmaceuticals and metabolites in the St. Lawrence watershed. Surface water samples were collected over a five-year period (2017-2021) along a 700-km reach of the St. Lawrence River as well as 55 tributary rivers (overall N = 406 samples). Additionally, depth water samples and sediments were collected near a major wastewater effluent. Caffeine, diclofenac, and venlafaxine were the most recurrent substances (detection rates >80 %), and extremely high levels were found near a municipal effluent (e.g., ibuprofen (860 ng/L), hydroxyibuprofen (1800 ng/L) and caffeine (7200 ng/L)). Geographical mapping and statistical analyses indicated that the St. Lawrence River water mass after the Montreal City effluent was significantly more contaminated than the other water masses, and that contamination could extend up to 70 km further downstream. This phenomenon was repeatedly observed over the five years of sampling, confirming that this is not a random trend. A slight increase in contamination was also observed near Quebec City, but concentrations rapidly declined in the estuarine transition zone. Tributaries with the highest pharmaceutical levels (ΣPharmas ∼400-900 ng/L) included the Mascouche, Saint-Régis, and Bertrand rivers, all located in the densely populated Greater Montreal area. When flowrate was factored in, the top five tributaries in terms of mass load (ΣPharmas ∼200-2000 kg/year) were the Des Prairies, Saint-François, Richelieu, Ottawa, and Yamaska rivers. All samples met the Canadian Water Quality Guideline for carbamazepine. Despite the large dilution effect of the St. Lawrence River, a risk quotient approach based on freshwater PNEC values suggested that four compounds (caffeine, carbamazepine, diclofenac, and ibuprofen) could present intermediate to high risks for aquatic organisms in terms of chronic exposure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Methods targeting anionic per- and polyfluoroalkyl substances (PFAS) in aquatic biota are well established, but commonly overlook many PFAS classes present in aqueous film-forming foams (AFFFs). Here, we developed an analytical method for the expanded analysis of negative and positive ion mode PFAS in fish tissues. Eight variations of extraction solvents and clean-up protocols were first tested to recover 70 AFFF-derived PFAS from the fish matrix. Anionic, zwitterionic, and cationic PFAS displayed the best responses with methanol-based ultrasonication methods. The response of long-chain PFAS was improved for extracts submitted to graphite filtration alone compared with those involving solid-phase extraction. The validation included an assessment of linearity, absolute recovery, matrix effects, accuracy, intraday/interday precision, and trueness. The method was applied to a set of freshwater fish samples collected in 2020 in the immediate vicinity (creek, n = 15) and downstream (river, n = 15) of an active fire-training area at an international civilian airport in Ontario, Canada. While zwitterionic fluorotelomer betaines were major components of the subsurface AFFF source zone, they were rarely detected in fish, suggesting limited bioaccumulation potential. PFOS largely dominated the PFAS profile, with record-high concentrations in brook sticklebacks (Culaea inconstans) from the creek (16000-110,000 ng/g wet weight whole-body). These levels exceeded the Canadian Federal Environmental Quality Guidelines (FEQG) for PFOS pertaining to the Federal Fish Tissue Guideline (FFTG) for fish protection and Federal Wildlife Diet Guidelines (FWiDG) for the protection of mammalian and avian consumers of aquatic biota. Perfluorohexane sulfonamide and 6:2 fluorotelomer sulfonate were among the precursors detected at the highest levels (maximum of ∼340 ng/g and ∼1100 ng/g, respectively), likely reflecting extensive degradation and/or biotransformation of C6 precursors originally present in AFFF formulations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Some contemporary aqueous film-forming foams (AFFFs) contain n :3 and n :1:2 fluorotelomer betaines (FTBs), which are often detected at sites impacted by AFFFs. As new chemical replacements, little is known about their environmental fate. For the first time, we investigated the biotransformation potential of 5:3 and 5:1:2 FTBs and a commercial AFFF that mainly contains n :3 and n :1:2 FTBs ( n = 5, 7, 9, 11, and 13). Although some polyfluoroalkyl compounds are precursors to perfluoroalkyl acids, 5:3 and 5:1:2 FTBs exhibited high persistence, with no significant changes even after 120 days of incubation. While the degradation of 5:3 FTB into suspected products such as fluorotelomer acids or perfluoroalkyl carboxylic acids (PFCAs) could not be conclusively confirmed, we did identify a potential biotransformation product, 5:3 fluorotelomer methylamine. Similarly, 5:1:2 FTB did not break down or produce short-chain hydrogen-substituted polyfluoroalkyl acids ( n :2 H-FTCA), hydrogen-substituted PFCA (2H-PFCA), or any other products. Incubating the AFFF in four soils with differing properties and microbial communities resulted in 0.023-0.25 mol % PFCAs by day 120. Most of the products are believed to be derived from n :2 fluorotelomers, minor components of the AFFF. Therefore, the findings of the study cannot be fully explained by the current understanding of structure-biodegradability relationships.

Limited monitoring data are available regarding the occurrence of emerging per- and polyfluoroalkyl substances (PFAS) in drinking water. Here, we validated an analytical procedure for 42 PFAS with individual detection limits of 0.001-0.082 ng/L. We also evaluated how different sample pH conditions, dechlorinating agents, and storage holding times might affect method performance. PFAS were analyzed in tap water samples collected at a large spatial scale in Quebec, Canada, covering 376 municipalities within 17 administrative regions. Target and nontarget screening revealed the presence of 31 and 23 compounds, respectively, representing 24 homolog classes. Overall, 99.3% of the tap water samples were positive for at least one PFAS, and the ƩPFAS ranged from below detection limits to 108 ng/L (95th percentile: 13 ng/L). On average, ƩPFAS was 12 times higher in tap water produced from surface water than groundwater; however, 6 of the top 10 contaminated locations were groundwater-based. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) had high detection rates (88% and 80%, respectively). PFOS (median: 0.15 ng/L; max: 13 ng/L) and PFOA (median: 0.27 ng/L; max: 8.1 ng/L) remained much lower than current Health Canada guidelines but higher than USEPA's interim updated health advisories. Short-chain (C3-C6) perfluoroalkyl sulfonamides were also recurrent, especially the C4 homolog (FBSA: detection rate of 50%). The 6:2 fluorotelomer sulfonyl propanoamido dimethyl ethyl sulfonate (6:2 FTSO2PrAd-DiMeEtS) was locally detected at ∼15 ng/L and recurred in 8% of our samples. Multiple PFAS that are most likely to originate from aqueous film-forming foams were also reported for the first time in tap water, including X:3 and X:1:2 fluorotelomer betaines, hydroxylated X:2 fluorotelomer sulfonates, N-trimethylammoniopropyl perfluoroalkane sulfonamides (TAmPr-FHxSA and TAmPr-FOSA), and N-sulfopropyl dimethylammoniopropyl perfluoroalkane sulfonamidopropyl sulfonates (N-SPAmP-FPeSAPS and N-SPAmP-FHxSAPS)., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The widespread distribution of contaminants of emerging concern (CECs) is a major concern due to their potential effects on human health and the environment. The insufficient sewage treatment plant infrastructures is a global problem most accentuated in less developed countries and results in the discharge of CECs to water bodies. Pacu (Piaractus mesopotamicus) is a ray-finned freshwater fish species native to the Paraná basin. It is also the most produced aquaculture fish species in Argentina since 2012. Though uninvestigated to date, the occurrence of CECs in pacu may be of high relevance due to production volumes and relevance to human exposure through fish consumption. In this study, we applied a high-resolution mass spectrometry screening method to qualitatively analyze over 100 CECs in pacu. Four extraction/cleanup methods were tested on pooled pacu fillet, including solid-phase extraction and QuEChERS. The method that produced the highest number of detections was selected for further analysis of pacu purchased in supermarkets and fish markets in Argentina between 2017 and 2020. Residues of pesticides, antibiotics, pharmaceuticals, personal care products, plasticizers, sweeteners, drug metabolites, stimulants, and illegal drugs were detected in the samples. A total of 38 CECs were detected, ranging between 24 and 35 CECs per individual sample. 100% of the samples had positive detections of caffeine, 1,7-dimethylxanthine, xanthine, benzoylecgonine, methylparaben, ethylparaben, bis(2-ethylhexyl) phthalate (DEHP), metolachlor, carbendazim, salicylic acid, 2,4-D, saccharin, cyclamate, and dodecanedioic acid. Mappings generated with correspondence analysis were used to explore similarities/dissimilarities among the detected compounds. To our knowledge this is the first report of saccharin, cyclamate, 2,4 - D, carbendazim, metolachlor, ethylparaben, propylparben, bisphenol A, DEHP, and benzotriazole in fish from Argentina, and the first report on the presence of lisinopril, metropolol acid and dodecanedioic acid in fish worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Quantification of drugs residues in wastewaters of different sources could help better understand contamination pathways, eventually leading to effluent regulation. However, limited data are available for hospital-derived wastewaters. Here, an analytical method based on automated on-line solid-phase extraction liquid chromatography tandem mass spectrometry (on-line SPE - UPLC-MS/MS) was developed for the quantification of multi-class pharmaceuticals in wastewaters. Filtrate phase and suspended solids (SPM) were both considered to evaluate the distribution of targeted analytes. Experimental design optimization involved testing different chromatographic columns, on-line SPE columns, and loading conditions for the filtrate phase, and different organic solvents and cleanup strategies for suspended solids. The selected methods were validated with suitable limits of detection, recovery, accuracy, and precision. A total of 30 hospital effluents and 6 wastewater treatment plants were sampled to evaluate concentrations in real field-collected samples. Certain pharmaceuticals were quantified at high levels such as caffeine at 670,000 ng/L in hospital wastewaters and hydroxyibuprofen at 49,000 ng/L in WWTP influents. SPM samples also had high contaminant concentrations such as ibuprofen at 31,000 ng/g in hospital effluents, fluoxetine at 529 ng/g in WWTP influents or clarithromycin at 295 ng/g in WWTP effluents. Distribution coefficients (K d ) and particle-associated fractions (Φ) indicate that pharmaceuticals tend to have better affinity to suspended solids in hospital wastewater than in municipal wastewaters. The results also bring arguments for at source treatment of these specific effluents before their introduction into urban wastewater systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Cyanobacterial blooms present challenges for water treatment, especially in regions like the Canadian prairies where poor water quality intensifies water treatment issues. Buoyant cyanobacteria that resist sedimentation present a challenge as water treatment operators attempt to balance pre-treatment and toxic disinfection by-products. Here, we used microscopy to identify and describe the succession of cyanobacterial species in Buffalo Pound Lake, a key drinking water supply. We used indicator species analysis to identify temporal grouping structures throughout two sampling seasons from May to October 2018 and 2019. Our findings highlight two key cyanobacterial bloom phases - a mid-summer diazotrophic bloom of Dolichospermum spp. and an autumn Planktothrix agardhii bloom. Dolichospermum crassa and Woronichinia compacta served as indicators of the mid-summer and autumn bloom phases, respectively. Different cyanobacterial metabolites were associated with the distinct bloom phases in both years: toxic microcystins were associated with the mid-summer Dolichospermum bloom and some newly monitored cyanopeptides (anabaenopeptin A and B) with the autumn Planktothrix bloom. Despite forming a significant proportion of the autumn phytoplankton biomass (>60%), the Planktothrix bloom had previously not been detected by sensor or laboratory-derived chlorophyll- a . Our results demonstrate the power of targeted taxonomic identification of key species as a tool for managers of bloom-prone systems. Moreover, we describe an autumn Planktothrix agardhii bloom that has the potential to disrupt water treatment due to its evasion of detection. Our findings highlight the importance of identifying this autumn bloom given the expectation that warmer temperatures and a longer ice-free season will become the norm.

Zwitterionic, cationic, and anionic per- and polyfluoroalkyl substances (PFAS) are increasingly reported in terrestrial and aquatic environments, but their inputs to agricultural lands are not fully understood. Here, we characterized PFAS in 47 organic waste products (OWP) applied in agricultural fields of France, including historical and recent materials. Overall, 160 PFAS from 42 classes were detected from target screening and homologue-based nontarget screening. Target PFAS were low in agriculture-derived wastes such as pig slurry, poultry manure, or dairy cattle manure (median ∑ 46 PFAS: 0.66 μg/kg dry matter). Higher PFAS levels were reported in urban and industrial wastes, paper mill sludge, sewage sludge, or residual household waste composts (median ∑ 46 PFAS: 220 μg/kg). Historical municipal biosolids and composts (1976-1998) were dominated by perfluorooctanesulfonate (PFOS), N -ethyl perfluorooctanesulfonamido acetic acid (EtFOSAA), and cationic and zwitterionic electrochemical fluorination precursors to PFOS. Contemporaneous urban OWP (2009-2017) were rather dominated by zwitterionic fluorotelomers, which represented on average 55% of ∑ 160 PFAS (max: 97%). The fluorotelomer sulfonamidopropyl betaines (X:2 FTSA-PrB, median: 110 μg/kg, max: 1300 μg/kg) were the emerging class with the highest occurrence and prevalence in contemporary urban OWP. They were also detected as early as 1985. The study informs for the first time that urban sludges and composts can be a significant repository of zwitterionic and cationic PFAS.

EPA method 539.1 recently introduced an expanded list of priority endocrine-disrupting compounds (EDCs), some of which were also included in the Unregulated Contaminant Monitoring Rule 3 (UCMR3). Though standardized methods are available for drinking water, analysis of steroid hormones and bisphenol A (BPA) at the ultra-trace level remains challenging. This study set out to evaluate the suitability of automated off-line solid-phase extraction (SPE) liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for the determination of EPA-priority EDCs in environmental water matrixes (tap water, surface water, and wastewater influents and effluents). The target molecules included 14 steroid hormones (altrenogest, androstenedione, equilenin, equilin, α-estradiol, β-estradiol, estriol, estrone, ethinylestradiol, levonorgestrel, medroxyprogesterone, norethindrone, progesterone, testosterone) and BPA. Factors that may influence the analytical performance were assessed. This involved, for instance, testing combinations of SPE materials from different brands and protocol variations. Several materials presented absolute extraction efficiencies in acceptable ranges. Initial sample pH, nature of reconstitution medium, and mobile phase salt concentration were among the potential factors affecting analyte signal. Storage conditions (different preservative agents) possibly exerted the strongest influence, in agreement with the literature. Limits of detection were in the range of 0.03-0.5 ng/L in drinking water, 0.1-0.5 ng/L in surface water, and 0.16-1 ng/L in wastewater. Method validation also involved testing linearity, accuracy, and precision in reagent water and matrix-matched extracted calibrants. The method was applied to field-collected water samples in Eastern Canada. Summed EDC concentrations remained low in tap water (

The proliferation of harmful cyanobacterial algal blooms is of concern due to the associated release of toxins affecting ecosystems and human health. The paralytic shellfish poison saxitoxin (STX) is a small polar alkaloid that can occur in inland and marine aquatic environments. Here, we optimized a fast and sensitive analytical method for the determination of STX, neosaxitoxin (NeoSTX), and their decarbamoyl analogues in surface waters. The method involves a simple filtration, addition of isotope-labelled internal standard (ILIS), and analysis by on-line solid-phase extraction coupled to hydrophilic interaction liquid chromatography high-resolution mass spectrometry (on-line SPE-HILIC-HRMS). Except glass fiber filters, other tested materials (e.g., nylon, nitrocellulose) provided suitable filtration performance. Time-dependent adsorptive losses occurred during the LC-MS batch sequence if glass autosampler vials were used, while no such effect was observed for polypropylene autosampler vials. Matrix effects were evaluated for 4 different quantification scenarios, including external vs. internal curves and neat reagent water vs. matrix-matched curves. Matrix-matched calibration with ILIS correction (NeoSTX- 15 N 7 ) provided the best performance overall. The analytical method was validated in freshwater lake water and estuarine brackish water (30‰ salinity), with suitable determination coefficients (R 2  > 0.9975), matrix spike accuracy (90-107%), and intraday/interday precision (RSD of 0.61-16%). Method limits of detection (LOD in lake water: 0.72-3.9 ng/L) are also improved over most of the recent literature. The method was applied to a set of 302 surface water samples collected in Canada, France, and the United Kingdom, and positive detections were reported for STX (max: 98 ng/L), decarbamoyl-STX (max: 15 ng/L), and NeoSTX (max: 87 ng/L)., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Emerging PFAS were recently reported at sites impacted by aqueous film-forming foams (AFFFs) and near major manufacturing centers; however, few studies have evaluated whether these can occur far from release sites. Here, newly identified PFAS were investigated in wild sporting fish from boreal freshwater ecosystems (background sites, 2013-2014 summer seasons), compared to fish impacted by a major AFFF release (summer 2013 and autumn 2014). Different freshwater wild sporting fish species (Esox lucius, Esox masquinongy, Micropterus dolomieu, Sander vitreus, Perca flavescens, and Semotilus corporalis, n = 74) were collected from 13 ecosystems (lakes, reservoirs, and rivers) across Eastern Canada. Of 29 quantitative PFAS, 15 compounds were detected in fish from background sites, including perfluorocarboxylates (C 6,8 - 14 ), perfluoroalkane sulfonates (C 6,8,10 ), perfluorooctane sulfonamide (FOSA), 6:2 fluorotelomer sulfonate (6:2 FTSA), 7:3 fluorotelomer carboxylic acid (7:3 FTCA), and a zwitterionic PFAS-perfluorooctane sulfonamidoalkyl betaine (PFOSB). To our knowledge, this is the first report of PFOSB in biota. It is also one of the first reports of anionic fluorotelomers (6:2 FTSA, 7:3 FTCA, 9:3 FTCA) in wildlife from background sites. Long-chain fluorotelomer sulfonamidoalkyl betaines (e.g., 8:2 and 10:2 FTAB), fluorotelomer betaines (e.g., 9:3 and 9:1:2 FTB), and fluorotelomer sulfone propanoic acids (e.g., 8:2 FT(SO 2 )-PA, 10:2 FT(SO 2 )-PA)) were solely prevalent (up to 97% of summed suspect PFAS) in Smallmouth Bass (M. dolomieu) from the AFFF-impacted site. Perfluorobutane sulfonamide (FBSA), perfluorohexane sulfonamide (FHxSA), 6:2 FTSA and 7:3 FTCA were detected in at least one Smallmouth Bass sample both at the AFFF-impacted and background sites. According to the estimated chronic daily intake and current tolerable daily intake suggested by national agencies, the observed PFOS levels would not pose a health risk to anglers who might consume these wild-caught fish., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The neurotoxic alkaloid β-N-methyl-amino-l-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), β-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5−10 ng L−1. Higher detection rates and significantly greater levels (paired Wilcoxon’s signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67−8.25 for AEG (up to +725%) and 0.69−15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L−1 for AEG and +650 ng L−1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L−1 and 1100 ng L−1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2−4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation.

In urban areas served by separate sewerage systems, illicit connections to the storm drain system from residences or commercial establishments are frequent whether these misconnections were made accidentally or deliberately. As a result, untreated and contaminated wastewater enters into storm sewers leading to pollution of receiving waters and non-compliance with water quality standards. Typical procedures for detecting illicit connections to the storm sewer system are time consuming and expensive, especially in a highly urbanised area. In this study, we investigated the use of human wastewater micropollutants WWMPs (caffeine, theophylline, and carbamazepine) and advanced DNA molecular markers (human specific Bacteroides HF183 and mitochondrial DNA) as anthropogenic tracers in order to assist identifying potential cross connections. Water samples from storm outfalls and storm sewer pipes in three urban subcatchments were collected in dry weather from 2013 to 2018. All samples contained various concentrations of these markers especially HF183, caffeine and theophylline, suggesting that the storm pipe system studied is widely contaminated by sanitary sewers. None of the traditional indicators or markers tested is sufficient alone to determine the origin of fecal pollution. In a highly urbanised area, the combination of at least three specific human markers was needed in order to locate the residential section with likely misconnections. The human specific Bacteroides HF183, and theophylline appeared to be the most effective markers (along with E. coli) of crossconnections, whereas carbamazepine can provide an indication of contamination through sanitary sewer exfiltration. A composite sewer cross-connection index was developed, and eight misconnected houses were identified and corrected. The index approach enables the reduction of false positives that could lead to expensive interventions to identify cross-connected households. The results show the multiparameter source tracking toolbox as an effective method to identify sewer cross connections for sustainable storm water management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Global warming and eutrophication may lead to increased incidence of harmful algal blooms and related production of cyanotoxins that can be toxic to aquatic plants. Previous studies have evaluated the phytotoxic effects of cyanotoxins on aquatic plants. However, most studies have evaluated only a limited number of plant species and cyanotoxins; there is also considerable variability between studies, which obscures general patterns and hinders understanding of the phytotoxic effects of cyanotoxins. Here, we conducted a comprehensive meta-analysis by compiling 41 published papers to estimate the phytotoxic effects of anatoxin-a, cylindrospermopsin, and microcystins in 34 species of aquatic plants, with the aim of 1) investigating the phytotoxicity of different cyanotoxins to aquatic plants; 2) determining the aquatic plant species most sensitive to the phytotoxic effects of cyanotoxins; and 3) evaluating the bioaccumulation potential of cyanotoxins in aquatic plants. Most aquatic plants were negatively affected by cyanotoxin exposure and their response was dose-dependent; however, morphological indicators and photosynthesis of certain aquatic plants were marginally stimulated under low concentrations of anatoxin-a and cylindrospermopsin. Anatoxin-a showed the greatest bioaccumulation capacity in aquatic plants compared to cylindrospermopsin and microcystin variants. Bioaccumulation factors of cyanotoxins in aquatic plants generally decreased with increasing water exposure concentrations. Our study supports the One Health goal to manage the risk of public exposure to toxic substances, and indicates that cyanotoxins warrant further investigations in aquatic plants. Environmental managers and public health authorities need to be alert to the long-term exposure and chronic toxicity of cyanotoxins, and the potential trophic transfer of cyanotoxins from aquatic plants to higher-order organisms., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The occurrence of 93 classes of per- and polyfluoroalkyl substances (PFASs) was investigated at aqueous film-forming foam (AFFF)-impacted sites of four Canadian airports. Surface/subsurface soil and groundwater samples were characterized using high-resolution mass spectrometry (HRMS) and an improved total oxidizable precursor (TOP) assay. PFAS profiles, loads, and spatial trends were highly site-specific, influenced by the AFFF use history, variations in sorption, transport, and in situ transformation potential of PFASs. All sites have been impacted by more than one AFFF chemistry, with the active firefighter training area exhibiting a greater PFAS variety and total PFAS burden than decommissioned sites. Zwitterionic and cationic compounds composed a large percentage (34.5-85.5%) of the total PFAS mass in most surface soil samples in the source zone but a relatively low percentage (<20%) in groundwater samples. Background soils surrounding the source zone contained predominantly unidentified precursors attributed to atmospheric deposition, while in AFFF-impacted soils, precursors originating from AFFFs can be largely captured by HRMS using available suspect lists. Horizontal transfer of PFASs in surface soils was limited, but vertical migration down the soil column occurred even in locations of low permeability. This study provides a critical data set to support developing new priority analyte lists and integrating TOP assay for comprehensive PFAS monitoring at AFFF-impacted sites.