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Background: Microplastics are a pervasive contaminant cycling through food webs-leading to concerns regarding exposure and risk to humans., Objectives: We aimed to quantify and characterize anthropogenic particle contamination (including microplastics) in fish caught for human consumption from the Humber Bay region of Lake Ontario. We related quantities of anthropogenic particles to other factors (e.g., fish size) that may help in understanding accumulation of microplastics in fish., Methods: A total of 45 samples of six fish species collected from Humber Bay in Lake Ontario near Toronto, Ontario, Canada, were examined for anthropogenic particles in their gastrointestinal (GI) tracts and fillets. Using microscopy and spectroscopy, suspected anthropogenic particles were identified and characterized., Results: We observed anthropogenic particles in the GI tracts and fillets of all species. Individual fish had a mean ± standard deviation of 138 ± 231 anthropogenic particles, with a single fish containing up to 1,508 particles. GI tracts had 93 ± 226 particles/fish ( 9.8 ± 32.6 particles/gram), and fillets had 56 ± 61 particles/fish ( 0.5 ± 0.8 particles/gram). Based on a consumption rate of 2 servings/week, the average yearly human exposure through the consumption of these fish fillets would be 12,800 ± 18,300 particles., Discussion: Our findings suggest that consumption of recreationally caught freshwater fish can be a pathway for human exposure to microplastics. The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics. Currently, it is unclear what the effects of ingesting microplastics are for humans, but given that recreationally caught freshwater fish are one pathway for human exposure, these data can be incorporated into future human health risk assessment frameworks for microplastics. https://doi.org/10.1289/EHP13540.

Concentrations of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were analyzed and investigated in surficial sediment collected in 2018 from ten different nearshore sites in Lake Ontario and the St. Lawrence River influenced by inputs from varying urban and historical land uses. Sites were grouped into two categories of tributary and lake according to their location. Results show that tributary sites had higher concentrations of total chlorinated paraffin (CP) than lake sites. Humber Bay, a lake site, had the highest total CP concentration (55,000 ng/g TOC ) followed by Humber River, a tributary site (50,000 ng/g TOC ). The lowest concentrations were found in eastern Lake Ontario and Lake St. Francis in the St. Lawrence River (540 ng/g TOC ). Higher concentrations of chlorinated paraffins (CPs) were found where runoff and wastewater inputs from urban areas, current industrial activities, and population were the greatest. Levels of MCCPs were higher than SCCPs at all sites but one, Lake St. Francis. Among the SCCPs, C 13 and among the MCCPs C 14 were the dominant chain length alkanes, with C 14 being the highest among both groups. The SCCPs and MCCPs profiles suggest that they can be used to distinguish between sites impacted by local sources vs. sites impacted by short-/long-range transport of these chemicals., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Humans are exposed to differing levels of micro/nanoplastics (MNPs) through inhalation, but few studies have attempted to measure <1 μm MNPs in air, in part due to a paucity of analytical methods. We developed an approach to identify and quantify MNPs in indoor air using a novel pyrolysis gas chromatographic cyclic ion mobility mass spectrometer (pyr-GCxcIMS). Four common plastic types were targeted for identification, namely, (polystyrene (PS), polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA). The method was applied to size-resolved particulate (56 nm to 18 μm) collected from two different indoor environments using a Micro-Orifice Uniform Deposit Impactors (MOUDI) model 110 cascade impactor. Comprehensive two-dimensional separation by GCxcIMS also enabled the retrospective analysis of other polymers and plastic additives. The mean concentrations of MNP particles with diameters of <10 μm and <2.5 μm in the laboratory were estimated to be 47 ± 5 and 27 ± 4 μg/m 3 , respectively. In the private residence, the estimated concentrations were 24 ± 3 and 16 ± 2 μg/m 3 . PS was the most abundant MNP type in both locations. Nontargeted screening revealed the presence of plastic additives, such as TDCPP (tris(1,3-dichloro-2-propyl)phosphate) whose abundance correlated with that of polyurethane (PU). This is consistent with their use as flame retardants in PU-based upholstered furniture and building insulation. This study provides evidence of indoor exposure to MNPs and underlines the need for further study of this route of exposure to MNPs and the plastic additives carried with them.

Plastic microbeads were widely used as exfoliants in personal care products (PCPs; e.g., hand/body washes) in North America, but restrictions were imposed on their use in PCPs in the U.S. (2017) and Canada (2018). We provide the first assessment of whether restrictions are effectively reducing microbeads entering surface waters. We examined their abundance, character, and trends in wastewater treatment plant (WWTP) effluents in Toronto, Canada, from 2016 to 2019, and in adjacent Lake Ontario surface waters (2015 and 2018), encompassing the period before and after the bans. Microbeads isolated from PCPs purchased in 2015 provided a visual morphological key with "irregular" and "spherical" microbead categories. Median concentrations of irregular microbeads, composed of polyethylene plastic, declined by up to 86% in WWTP effluents from 8.4 to 14.3 particles/m 3 before to 2.0-2.2 particles/m 3 after the bans, while those of spherical microbeads, predominantly synthetic/polyethylene wax, ranged within 0.5-2.3 particles/m 3 and did not differ before and after the bans since, as nonplastic, they were not regulated. Similarly, amounts of irregular microbeads declined relative to spherical microbeads in Lake Ontario, indicating that product changes may be influencing observations in lake waters. The results suggest that the Canadian and U.S. restrictions effectively and rapidly reduced plastic microbeads entering waters via WWTPs., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Previous studies have evaluated method performance for quantifying and characterizing microplastics in clean water, but little is known about the efficacy of procedures used to extract microplastics from complex matrices. Here we provided 15 laboratories with samples representing four matrices (i.e., drinking water, fish tissue, sediment, and surface water) each spiked with a known number of microplastic particles spanning a variety of polymers, morphologies, colors, and sizes. Percent recovery (i.e., accuracy) in complex matrices was particle size dependent, with ∼60-70% recovery for particles >212 μm, but as little as 2% recovery for particles <20 μm. Extraction from sediment was most problematic, with recoveries reduced by at least one-third relative to drinking water. Though accuracy was low, the extraction procedures had no observed effect on precision or chemical identification using spectroscopy. Extraction procedures greatly increased sample processing times for all matrices with the extraction of sediment, tissue, and surface water taking approximately 16, 9, and 4 times longer than drinking water, respectively. Overall, our findings indicate that increasing accuracy and reducing sample processing times present the greatest opportunities for method improvement rather than particle identification and characterization., Competing Interests: Declaration of competing interest Leah M. Thornton Hampton, Hannah De Frond, Kristine Gesulga, Syd Kotar, Wenjian Lao, Cindy Matuch, Stephen B. Weisberg, Charles S. Wong, Susanne Brander, Silke Christansen, Cayla R. Cook, Fangni Du, Sutapa Ghosal, Andrew B. Gray, Jeanne Hankett, Paul A. Helm, Kay T. Ho, Timnit Kefela, Gwendolyn Lattin, Amy Lusher, Lei Mai, Rachel E. McNeish, Odette Mina, Elizabeth C. Minor, Sebastian Primpke, Keith Rickabaugh, Violet C. Renick, Samiksha Singh, Bert van Bavel, Florian Vollnhals, and Chelsea M. Rochman declare having no known competing financial interests or professional relationships that could have appeared to influence the work reported in this manuscript., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Persistent organic pollutants (POPs) are recognized as pollutants of global concern, but so far, information on the trends of legacy POPs in the waters of the world has been missing due to logistical, analytical, and financial reasons. Passive samplers have emerged as an attractive alternative to active water sampling methods as they accumulate POPs, represent time-weighted average concentrations, and can easily be shipped and deployed. As part of the AQUA-GAPS/MONET, passive samplers were deployed at 40 globally distributed sites between 2016 and 2020, for a total of 21 freshwater and 40 marine deployments. Results from silicone passive samplers showed α-hexachlorocyclohexane (HCH) and γ-HCH displaying the greatest concentrations in the northern latitudes/Arctic Ocean, in stark contrast to the more persistent penta (PeCB)- and hexachlorobenzene (HCB), which approached equilibrium across sampling sites. Geospatial patterns of polychlorinated biphenyl (PCB) aqueous concentrations closely matched original estimates of production and use, implying limited global transport. Positive correlations between log-transformed concentrations of Σ 7 PCB, ΣDDTs, Σendosulfan, and Σchlordane, but not ΣHCH, and the log of population density ( p < 0.05) within 5 and 10 km of the sampling sites also supported limited transport from used sites. These results help to understand the extent of global distribution, and eventually time-trends, of organic pollutants in aquatic systems, such as across freshwaters and oceans. Future deployments will aim to establish time-trends at selected sites while adding to the geographical coverage.

Microplastic categorization schemes are diverse, thereby posing challenges for cross-study comparisons. Further, categorization schemes are not necessarily aligned with and, thus, useful for applications such as source reduction initiatives. To address these challenges, we propose a hierarchical categorization approach that is "fit for purpose" to enable the use of a scheme that is tailored to the study's purpose and contains categories, which, if adopted, would facilitate interstudy comparison. The hierarchical categorization scheme is flexible to support various study purposes (e.g., to support regulation and toxicity assessment) and it aims to improve the consistency and comparability of microplastics categorization. Categorization is primarily based on morphology, supplemented by other identification methods as needed (e.g., spectroscopy). The use of the scheme was illustrated through a literature review aimed at critically evaluating the categories used for reporting microplastic morphologies in North American freshwater environments. Categorization and grouping schemes for microplastic particles were highly variable, with up to 19 different categories used across 68 studies, and nomenclature was inconsistent across particle morphologies. Our review demonstrates the necessity for a "fit for purpose" categorization scheme to guide the information needs of scientists and decision-makers for various research and regulatory objectives across global, regional, and local scales. Integr Environ Assess Manag 2023;19:422-435. © 2022 SETAC., (© 2022 SETAC.)

Introduction: The rapid growth in the worldwide use of plastics has resulted in a vast accumulation of microplastics in the air, soil and water. The impact of these microplastics on pregnancy and fetal development remains largely unknown. In pregnant mice, we recently demonstrated that exposure to micro- and nanoplastics throughout gestation resulted in significant fetal growth restriction. One possible explanation for reduced fetal growth is abnormal placental metabolism., Objectives: To evaluate the effect of maternal exposure to microplastics on placental metabolism., Methods: In the present study, CD-1 pregnant mice were exposed to 5 μm polystyrene microplastics in filtered drinking water at one of four concentrations (0 ng/L (controls), 10 2 ng/L, 10 4 ng/L, 10 6 ng/L) throughout gestation (n = 7-11/group). At embryonic day 17.5, placental tissue samples were collected (n = 28-44/group). Metabolite profiles were determined using 1  H high-resolution magic angle spinning magnetic resonance spectroscopy., Results: The relative concentration of lysine (p = 0.003) and glucose (p < 0.0001) in the placenta were found to decrease with increasing microplastic concentrations, with a significant reduction at the highest exposure concentration. Multivariate analysis identified shifts in the metabolic profile with MP exposure and pathway analysis identified perturbations in the biotin metabolism, lysine degradation, and glycolysis/gluconeogenesis pathways., Conclusion: Maternal exposure to microplastics resulted in significant alterations in placental metabolism. This study highlights the potential impact of microplastic exposure on pregnancy outcomes and that efforts should be made to minimize exposure to plastics, particularly during pregnancy., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Pathways for microplastics to aquatic ecosystems include agricultural runoff, urban runoff, and treated or untreated wastewater. To better understand the importance of each pathway as a vector for microplastics into waterbodies and for mitigation, we sampled agricultural runoff, urban stormwater runoff, treated wastewater effluent, and the waterbodies downstream in four regions across North America: the Sacramento Delta, the Mississippi River, Lake Ontario, and Chesapeake Bay. The highest concentrations of microplastics in each pathway varied by region: agricultural runoff in the Sacramento Delta and Mississippi River, urban stormwater runoff in Lake Ontario, and treated wastewater effluent in Chesapeake Bay. Material types were diverse and not unique across pathways. However, a PERMANOVA found significant differences in morphological assemblages among pathways ( p < 0.005), suggesting fibers as a signature of agricultural runoff and treated wastewater effluent and rubbery fragments as a signature of stormwater. Moreover, the relationship between watershed characteristics and particle concentrations varied across watersheds (e.g., with agricultural parameters only being important in the Sacramento Delta). Overall, our results suggest that local monitoring is essential to inform effective mitigation strategies and that assessing the assemblages of morphologies should be prioritized in monitoring programs to identify important pathways of contamination.

Offshore and nearshore sediment samples from Lake Huron, North America, were analysed for microplastics. Normalized abundances ranged from 59 to 335,714 particles per kg of dry weight sediment (p kg -1 dw). Of the four main basins of Lake Huron, the North Channel contained the greatest microplastic abundances, averaging 47,398 p kg -1 dw, followed by Georgian Bay (21,390 p kg -1 dw), the main basin (15,910 p kg -1 dw) and Saginaw Bay (1592 p kg -1 dw). Results indicate that greater lake depths (p = 0.004), associated with finer grained sediment (p = 0.048), are significant zones of deposition. Regression analysis reveals that source-driven factors generally do not account for microplastic abundances and distribution. Instead, process-driven hydrodynamic forces such as waves and surface currents could be driving distribution and deposition into the offshore environment. The findings suggest that these often overlooked processes should be considered when investigating microplastics quantity in bottom sediment of large lakes., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Organophosphate esters (OPEs) are flame retardant and plasticizer chemicals added to electronics, furniture, textiles, and other building materials and consumer products. In this study, fillets of fish often caught by anglers in the North American Great Lakes, Lake Trout (Salvelinus namaycush) across four Great Lakes and nearshore fish species near the large urban and industrial centers of Toronto and Hamilton, Canada, were analyzed for 22 OPEs. A rapid microextraction of homogenized tissues with methanol dramatically reduced preparation and sample handling time while achieving recoveries of 69-141%, and the optimized liquid chromatographic separation improved isomeric separations, including aryl-OPEs. Twelve of the 22 OPEs were detected, with frequencies of detection ranging from 8.3% to 98%, and five compounds were detected in >50% of the fish. The average ± standard deviation for the sum of 12 OPEs (ΣOPE 12 ) ranged from 9.6 ± 0.9 (L. Erie 2017) to 74 ± 44 (L. Superior 2001) ng/g wet weight in Lake Trout, and 12 ± 2.7 to 35 ± 30 ng/g wet weight in nearshore fish species from the Toronto and Hamilton areas. The aryl-OPEs were dominant in Lake Trout, comprising 32-77% of total ΣOPE 12 concentrations. In nearshore fish, the OPE patterns reflected the relative degree of exposure to run-off and wastewater inputs in the sampled receiving environments. The intake of OPEs via human consumption of Great Lakes Lake Trout and nearshore fish was estimated to range 6.5-31 ng/kg body weight/day, which is approximately 1-2 orders of magnitude lower than exposures via indoor air and ingestion/inhalation of dusts, and 3 orders of magnitude lower than estimated reference doses. The inclusion of additional OPE analytes enabled patterns of exposure and accumulation to be distinguished in fish of different species and location, and were related to source and food web influences., 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.)

Freshwater ecosystems, generally adjacent to human population and more contaminated relative to adjacent marine ecosystems, are vulnerable to microplastic contamination. We sampled 7 species of fish from Lake Ontario and Lake Superior and assessed their gastrointestinal (GI) tracts to quantify ingested microplastics and other anthropogenic particles. A subset of the microparticles were chemically analyzed to confirm polymer types and anthropogenic origins. We documented the highest concentration of microplastics and other anthropogenic microparticles ever reported in bony fish. We found 12,442 anthropogenic microparticles across 212 fish (8 species) from nearshore Lake Ontario, 943 across 50 fish (1 species) from Humber River, and 3094 across 119 fish (7 species) from Lake Superior. Fish from Lake Ontario had the greatest mean abundance of anthropogenic microparticles in their GI tracts (59 particles/fish [SD 104]), with up to 915 microparticles in a single fish. Fish from Lake Superior contained a mean [SD] of 26 [74] particles/fish, and fish from Humber River contained 19 [14] particles/fish. Most particles were microfibers. Overall, ≥90% of particles were anthropogenic, of which 35-59% were microplastics. Polyethylene (24%), polyethylene terephthalate (20%), and polypropylene (18%) were the most common microplastics. Ingestion of anthropogenic particles was significantly different among species within Lake Ontario (p < 0.05), and the abundance of anthropogenic particles increased as fish length increased in Lake Ontario (ρ = 0.62). Although we cannot extrapolate the concentration of microplastics in the water and sediments of these fish, the relatively high abundance of microplastics in the GI tracts of fish suggests environmental exposure may be above threshold concentrations for risk., (© 2021 Society for Conservation Biology.)

Gas chromatography-high-resolution mass spectrometry (GC-HRMS) is a powerful nontargeted screening technique that promises to accelerate the identification of environmental pollutants. Currently, most GC-HRMS instruments are equipped with electron ionization (EI), but atmospheric pressure ionization (API) ion sources have attracted renewed interest because: (i) collisional cooling at atmospheric pressure minimizes fragmentation, resulting in an increased yield of molecular ions for elemental composition determination and improved detection limits; (ii) a wide range of sophisticated tandem (ion mobility) mass spectrometers can be easily adapted for operation with GC-API; and (iii) the conditions of an atmospheric pressure ion source can promote structure diagnostic ion-molecule reactions that are otherwise difficult to perform using conventional GC-MS instrumentation. This literature review addresses the merits of GC-API for nontargeted screening while summarizing recent applications using various GC-API techniques. One perceived drawback of GC-API is the paucity of spectral libraries that can be used to guide structure elucidation. Herein, novel data acquisition, deconvolution and spectral prediction tools will be reviewed. With continued development, it is anticipated that API may eventually supplant EI as the de facto GC-MS ion source used to identify unknowns.

NMR spectroscopy is arguably the most powerful tool for the study of molecular structures and interactions, and is increasingly being applied to environmental research, such as the study of wastewater. With over 97% of the planet's water being saltwater, and two thirds of freshwater being frozen in the ice caps and glaciers, there is a significant need to maintain and reuse the remaining 1%, which is a precious resource, critical to the sustainability of most life on Earth. Sanitation and reutilization of wastewater is an important method of water conservation, especially in arid regions, making the understanding of wastewater itself, and of its treatment processes, a highly relevant area of environmental research. Here, the benefits, challenges and subtleties of using NMR spectroscopy for the analysis of wastewater are considered. First, the techniques available to overcome the specific challenges arising from the nature of wastewater (which is a complex and dilute matrix), including an examination of sample preparation and NMR techniques (such as solvent suppression), in both the solid and solution states, are discussed. Then, the arsenal of available NMR techniques for both structure elucidation (e.g., heteronuclear, multidimensional NMR, homonuclear scalar coupling-based experiments) and the study of intermolecular interactions (e.g., diffusion, nuclear Overhauser and saturation transfer-based techniques) in wastewater are examined. Examples of wastewater NMR studies from the literature are reviewed and potential areas for future research are identified. Organized by nucleus, this review includes the common heteronuclei ( 13 C, 15 N, 19 F, 31 P, 29 Si) as well as other environmentally relevant nuclei and metals such as 27 Al, 51 V, 207 Pb and 113 Cd, among others. Further, the potential of additional NMR methods such as comprehensive multiphase NMR, NMR microscopy and hyphenated techniques (for example, LC-SPE-NMR-MS) for advancing the current understanding of wastewater are discussed. In addition, a case study that combines natural abundance (i.e. non-concentrated), targeted and non-targeted NMR to characterize wastewater, along with in vivo based NMR to understand its toxicity, is included. The study demonstrates that, when applied comprehensively, NMR can provide unique insights into not just the structure, but also potential impacts, of wastewater and wastewater treatment processes. Finally, low-field NMR, which holds considerable future potential for on-site wastewater monitoring, is briefly discussed. In summary, NMR spectroscopy is one of the most versatile tools in modern science, with abilities to study all phases (gases, liquids, gels and solids), chemical structures, interactions, interfaces, toxicity and much more. The authors hope this review will inspire more scientists to embrace NMR, given its huge potential for both wastewater analysis in particular and environmental research in general., 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 consumption of fish contaminated with microplastics is often cited as a pathway for human exposure. However, because their guts are generally removed before consumption, exposure may be low compared to other routes such as shellfish, drinking water and dust. Still, microplastics have been found to translocate from the gut to other tissues, making exposure from eating fish fillets or other seafood products a potential concern. To better understand fish as an exposure route for microplastics in humans, we tested hypotheses about whether translocation occurs and if efficiency of translocation is dependent on particle size. We investigated the amount and distribution of fluorescent polyethylene microspheres (10-300 μm) in the gut, liver, fillets and gonads of adult rainbow trout after a two-week dietary exposure. Fish were fed food pellets dosed with up to ~9,800 microspheres per gram of food. Total exposures over the entire experiment ranged from ~80,000-850,000 microspheres per fish. We did not find any particles in the fillets, liver, or gonads of any fish, suggesting that translocation of spherical microplastics of this size range does not occur in adult rainbow trout. The quantity of microplastics found in the gut was also low or absent after a 24-hour depuration period, indicating effective excretion in this laboratory population. This research suggests that the consumption of fish fillets may not be a significant exposure pathway for microspheres >10 μm in size to contaminate humans. Future studies should test for different sizes, morphologies and species to further our understanding., Competing Interests: The authors have declared that no competing interests exist.

Although passive sampling is widely accepted as an excellent tool for environmental monitoring, their integration with suspect or non-targeted screening by high-resolution mass spectrometry has been limited. This study describes the application of the organic-diffusive gradients in thin-films (o-DGT) passive sampler as a tool for accurate measurement of both targeted and suspect polar organic contaminants (primarily pharmaceuticals) in wastewater. First, performance of o-DGT was assessed alongside the polar organic chemical integrative sampler (POCIS) and active sampling at two wastewater treatment facilities using targeted analyses. Overall, water concentrations measured by o-DGT, POCIS, and 24-hr integrative active samples were in good agreement with each other. There were exceptions, including a systematic difference between o-DGT and POCIS at certain sites that we propose was a result of site-specific conditions and a difference in sampling rates between the two techniques. The second component of this work involved suspect screening of the o-DGT extracts using high-resolution, high mass accuracy quadrupole time-of-flight mass spectrometry (QTOF). Lamotrigine, venlafaxine, and des-methylvenlafaxine were three suspect compounds identified and selected as proof-of-concept case studies to determine the feasibility and accuracy of o-DGT for estimating water concentrations based upon predicted sampling rates using a previously validated o-DGT diffusion model. Semi-quantification of the suspect compounds was conducting using an average surrogate response factor based on the suite of compounds measured by the targeted analyses. This, combined with the modelled sampling rates provided time-weighted average wastewater concentrations of the identified suspects within a factor of 2 of the true value, confirmed by isotope dilution with mass labelled internal surrogates. To the knowledge of the authors, this work is the first to demonstrate the utility of the o-DGT passive sampler as a potential environmental screening tool that can be integrated into the rapidly advancing field of non-targeted high resolution mass spectrometry., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Microplastics are ubiquitous in the aquatic and terrestrial environment. To prevent further contamination, methods to determine their sources are needed. Techniques to quantify and characterize microplastics in the environment are still evolving for polymers and the additives and leachable substances embedded therein, which constitute the "chemical fingerprint" of an environmental microplastic. There is a critical need for analytical methods that yield such diagnostic information on environmental microplastics that enables identification of their composition and sources of pollution. This study reports on a novel approach for rapid fingerprinting of environmental microplastics and the screening of additives using Direct Analysis in Real Time (DART)-high resolution mass spectrometry. A variety of plastic samples were investigated, including virgin pre-production pellets, microbeads from personal care products, microplastics found in the aquatic environment, and synthetic fibers. The resulting mass spectra display ∼10,000 discrete peaks, corresponding to plastic additives released by thermal desorption and polymer degradation products generated by pyrolysis. These were used to characterize differences among plastic types, microplastic source materials, and environmental samples. Multivariate statistics and elemental composition analysis approaches were applied to analyze fingerprints from the mass spectra. This promising analytical approach is sensitive, (potentially) high-throughput, and can aid in the elucidation of possible sources of microplastics and perhaps eventually to the analysis of bulk environmental samples for plastics., 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 © 2019 Elsevier B.V. All rights reserved.)

Since 2001, twenty-eight halogenated groups of persistent organic pollutants (POPs) have been banned or restricted by the Stockholm Convention. Identifying new POPs among the hundreds of thousands of anthropogenic chemicals is a major challenge that is increasingly being met by state-of-the-art mass spectrometry (MS). The first step to identification of a contaminant molecule (M) is the determination of the type and number of its constituent elements, viz. its elemental composition, from mass-to-charge (m/z) measurements and ratios of isotopic peaks (M + 1, M + 2 etc.). Not every combination of elements is possible. Boundaries exist in compositional space that divides feasible and improbable compositions as well as different chemical classes. This study explores the compositional space boundaries of persistent and bioaccumulative organics. A set of ~305,134 compounds (PubChem) was used to visualize the compositional space occupied by F, Cl, and Br compounds, as defined by m/z and isotope ratios. Persistent bioaccumulative organics, identified by in silico screening of 22,049 commercial chemicals, reside in more constrained regions characterized by a higher degree of halogenation. In contrast, boundaries surrounding non-halogenated chemicals could not be defined. Finally, a script tool (R code) was developed to select potential POPs from high resolution MS data. When applied to household dust (SRM 2585), this approach resulted in the discovery of previously unknown chlorofluoro flame retardants., (Crown Copyright © 2019. Published by Elsevier Ltd. All rights reserved.)

Coal tar-based sealcoat (CTSC) products are an urban source of polycyclic aromatic compounds (PACs) to the environment. However, efforts to assess the environmental fate and impacts of CTSC-derived PACs are hindered by the ubiquity of (routinely monitored) PACs released from other environmental sources. To advance source identification of CTSC-derived PACs, we use comprehensive two-dimensional gas chromatography-high resolution mass spectrometry (GC × GC/HRMS) to characterize the major and minor components of CTSC products in comparison to those in other sources of PACs, viz., asphalt-based sealcoat products, diesel particulate, diesel fuel, used motor oil and roofing shingles. GC × GC/HRMS analyses of CTSC products led to the confident assignment of compounds with 88 unique elemental compositions, which includes a set of 240 individual PACs. Visualization of the resulting profiles using Kendrick mass defect plots and hierarchical cluster analysis highlighted compositional differences between the sources. Profiles of alkylated PAHs, and heteroatomic (N, O, S) PACs enabled greater specificity in source differentiation. Isomers of specific polycyclic aromatic nitrogen heterocycles (PANHs) were diagnostic for coal tar-derived PAC sources. The compounds identified and methods used for this identification are anticipated to aid in future efforts on risk assessment and source apportionment of PACs in environmental matrices.

Consumer products such as perfluorooctanesulfonic acid (PFOS) and pharmaceuticals (PCPPs) enter aquatic ecosystems through inefficient removal during wastewater treatment. Often, the sterilization process of wastewater includes the addition of sodium hypochlorite that can react with PCPPs and other organic matter (i.e., dissolve organic matter) to generate disinfection by-products and can cause the final effluent to be more harmful to aquatic organisms. Here, we exposed Daphnia magna to two stages of wastewater, the pre-chlorinated wastewater (PreCl) and the final effluent. In addition, we exposed D. magna, to the final effluent with a concentration gradient of added PFOS, to investigate if this persistent contaminant altered the toxicity of the final effluent. After 48 h of contaminant exposure, we measured the daphnids metabolic responses to the different stages of wastewater treatment, and with the addition of PFOS, utilizing proton nuclear magnetic resonance spectroscopy and liquid chromatography tandem mass spectrometry. We found few significant changes to the metabolic profile of animals exposed to the PreCl wastewater; however, animals exposed to the final effluent displayed increases in many amino acids and decreases in some sugar metabolites. With the addition of PFOS to the final effluent, the metabolic profile shifted from increased amino acids and decreased sugar metabolites and energy molecules especially at the low and high concentrations of PFOS. Overall, our results demonstrate the metabolome is sensitive to changes in the final effluent that are caused by sterilization, and with the addition of a persistent contaminant, the metabolic profile is further altered.

Sediment traps were deployed at seven sites in the western and central basins of Lake Ontario for calculation of concentrations and down fluxes for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) to assess ongoing loadings to Lake Ontario from the Niagara River watershed. Traps were deployed at multiple depths (beginning at 20 m) during two seasonal time periods at stations impacted by the outflow of the Niagara River, and stations reflecting deeper water offshore conditions. Settling particles were collected seasonally to assess the influence of physical characteristics of the water column, i.e., isothermal conditions vs. stratified conditions, on concentrations and fluxes of PCDD/Fs. At all stations and for all depth intervals, PCDD/F concentrations were higher in the winter sampling period (range of 3120-10,600 pg g -1 ), compared to the spring - summer - fall time period (range of 320-6900 pg g -1 ). These results indicated bottom sediments in central and western Lake Ontario were more highly-contaminated, compared to contemporary particulate material entering the lake via the Niagara River or resulting from shoreline erosion. However, assessment of PCDD/F congener profiles and ratios also indicated source areas within the Niagara River watershed continued to episodically contribute loadings to Lake Ontario. The results also indicated changes in discharges of PCDD/Fs from sources in the Niagara River result in changes in congener profiles in settling particles, which can be detected by continued monitoring., (Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.)

Organophosphate esters (OPEs), used as flame retardants and plasticizers, occur at relatively high concentrations in urban air and surface waters. We tested the hypothesis that some OPEs could be considered persistent and mobile organic compounds (PMOCs), using the poly parameter linear free energy relationship-modified Multimedia Urban Model (ppLFER-MUM) in Toronto, Canada, as a case study. Modeled air emissions of ∑ 6 OPEs of 3300 (190-190 000) kg yr -1 were 10-100 times higher than emissions of polychlorinated biphenyls (∑ 5 PCBs) and polybrominated diphenyl ethers (∑ 5 PBDEs). Model results suggested that measured ∑ 6 OPE stream concentrations of ∼2000 ng L -1 originate from emissions to urban air transferred to water mostly via precipitation. Water transport removed 7-28% of total air inputs compared to 0.1-10% for PCBs and 2-10% for PBDEs. Chlorinated OPEs were efficiently transported via surface water due to their persistence and high solubility. Loadings of ∑ 6 OPEs to Lake Ontario from wastewater treatment plants, streams, and atmospheric deposition were 70%, 18%, and 13%, respectively, of ∑ 6 OPE loadings of 3100 (1200-45 000) kg yr -1 . Our results support the hypothesis that three chlorinated OPEs, tris(2-chloroethyl)phosphate phosphate (TCEP), tris(chloroisopropyl)phosphate (TCiPP), and tris(1,3-dichloroisopropyl)phosphate (TDCiPP), fit the profile of PMOCs due to their mobility and persistence in surface waters.

Alkaline and wet peroxide oxidation chemical digestion techniques used to extract microplastics from organic matrices were assessed for recoveries and for impacts on ability to identify polymer types. Methods using wet peroxide oxidation generated enough heat to result in the complete loss of some types of microplastic particles, and boiling tests confirmed that temperatures >70 °C were responsible for the losses. Fourier transform infrared spectroscopy (FT-IR) confirmed minimal alteration of the recovered polymers by the applied methods. Environ Toxicol Chem 2018;37:91-98. © 2017 SETAC., (© 2017 SETAC.)

Organophosphorus flame retardants (OPFRs) started to be used in plastics, electronics and furnishings back in the 1960s and became popular again last decade. They are now widely present in the environment and regarded as "new" emerging organic pollutants. An effective liquid chromatography-tandem mass spectrometry (LC-MS/MS) direct injection analysis (DIA) method was developed to monitor OPFR levels in aquatic environment. The removal of sample extraction and concentration steps not only improved operation efficiency, but also reduced the potential contamination commonly observed during the sample preparation process before. Positive background signals from the analytical instrument were eliminated by employing a "trap" column in front of the sample injector while an ACE C18 and an ACE C18-PFP column were compared for the separation of OPFRs. Nineteen OPFR related compounds were evaluated and rapid signal drops were observed for seven of them including TOTP, TMTP, TPTP, TEHP, T35DMPP, T2iPPP and EHDP, due to their low water solubility. The other twelve compounds, TMP, TEP, TPrP, TiPP, TBP, TCEP, TCPP, TDCPP, TPP, TBEP, BDCP and BEHP, were included for the measurement of OPFRs in drinking water, surface water, ground water and wastewater effluent samples. The instrumental detection limits of these twelve OPFRs at signal-to-noise ≥3 were in the 1.5-30 ng/L range. The method was applied for the determination of OPFRs in surface water and wastewater samples in Ontario, Canada, and BEHP, TBEP, TBP, TCEP, TCPP, TDCPP, and TEP were commonly detected., (Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.)

Tris(chloropropyl) phosphate (TCPP) is an environmentally abundant organophosphate ester (OPE). TCPP is comprised of four isomers with seven possible structures, eight CAS numbers, and even more common names. A review of 54 studies reporting one or more TCPP isomers confirmed that the most abundant and most often reported TCPP isomer was tris(2-chloro-1-methylethyl) phosphate, also known as tris(chloroisopropyl) phosphate (TCiPP, referred to hereafter as TCPP1). Full-scan gas chromatography-mass spectrometry (GC-MS) was used to identify the other three isomers numbered here according to their elution order on a non-polar GC column (DB-5): bis(2-chloro-1-methylethyl) (2-chloropropyl) phosphate (TCPP2), bis(2-chloropropyl)(2-chloro-1-methylethyl) phosphate (TCPP3), and tris(2-chloropropyl) phosphate (TCPP4). GC with a flame ionization detector (FID) was used to identify the relative abundances of the isomers in commercially available standards with unknown isomer composition. In technical TCPP, TCPP1-4 isomers averaged 71 ± 1, 26 ± 0.4, 3 ± 0.5, and 0.1 ± 0.02%, respectively. When these percent masses are incorporated into GC-MS quantification, response factors (RFs) for TCPP1 and TCPP2 are significantly different from TCPP3 and TCPP4, indicating that the multiple RF approach is more accurate than the commonly employed single RF method. Samples from urban streams and wastewater treatment plant (WWTP) effluent from Toronto, Canada, had isomeric ratios of TCPP1/2 that were not significantly different from a technical mixture whereas rain had a significantly different ratio indicating enrichment in the more volatile TCPP1 isomer. Reporting TCPP isomers can provide insight into sources, transport, and fate of TCPP in the environment. Graphical Abstract ᅟ.

A method to determine halogenated flame retardants was developed that utilizes gas chromatography with atmospheric chemical ionization (APCI) high-resolution quadrupole time-of-flight mass spectrometry (HRqTOFMS). The new GC-APCI-HRqTOFMS method was used to determine the presence of 65 halogenated flame retardants (HFRs) in the United Sates National Institute of Standards and Technology (NIST) organic contaminants in house dust standard reference material (SRM). The accuracy of the measurements was compared to the certified NIST value for polybrominated diphenyl ethers (PBDEs) and had an average accuracy for the 14 certified PBDEs of 109% with subpicogram detection limits (on column) from a single 1 μL injection with a run time of 18 min. SRM2585 extracts were also analyzed by GC electron ionization (EI) high-resolution mass spectrometry (HRMS), and there was an excellent correlation between the two data sets (R 2 value of 0.996). The presence of 25 additional HFRs were also screened in the dust standard, and 10 were detected in concentrations above the limits of detection; these were p-TBX, PBBZ, PBT, PBEB, TDCPP, HBBZ, EHTBB, TBBPA, BEHTBP, and BTBPE. The results presented show that the proposed APCI-HRqTOFMS method was comparable and in many cases an improvement on the existing EI-HRMS method.

A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.1 ng/g), where perfluorooctane sulfonic acid (PFOS) contributed over 80% of the total. Concentrations in Lake Ontario were approximately 1-2 orders of magnitude greater than the more remote lakes subject to primarily atmospheric inputs. Whilst the PFAS contribution in Lake Ontario was dominated by PFOS, the more remote lakes contained sediment with higher proportions of PFCAs. Trace amounts of emerging PFASs (diPAPs and PFPiAs) were found in very recent surface Lake Ontario and remote lake sediments., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Polycyclic musks (PCMs) are synthetic fragrance compounds used in personal care products and household cleaners. Previous studies have indicated that PCMs are introduced to aquatic environments via wastewater and river discharge. Polyethylene passive samplers (PEs) were deployed in air and water during winter 2011 and summer 2012 to investigate the role of population centers as sources of these contaminants to the Great Lakes and determine whether the lakes were acting as sources of PCMs via volatilization. Average gaseous Σ 5 PCM ranged from below detection limits (3 on the western shoreline of Lake Erie in Toledo. Average dissolved Σ 5 PCM ranged from

5 PCM in both air and water, with strongest correlations within a 25 and 40 km radius, respectively. At sites where HHCB was detected it was generally volatilizing, while the direction of AHTN air-water exchange was variable. Volatilization fluxes of HHCB ranged from 11 ± 6 to 341 ± 127 ng/m 2 /day, while air-water exchange fluxes of AHTN ranged from -3 ± 2 to 28 ± 10 ng/m 2 /day. Extrapolation of average air-water exchange flux values over the surface area of the lakes' coastal boundary zone suggested volatilization may be responsible for the loss of 64-213 kg/year of dissolved Σ 5 PCM from the lakes.

Microplastics contamination of Lake Ontario sediments is investigated with the aim of identifying distribution patterns and hotspots in nearshore, tributary and beach depositional environments. Microplastics are concentrated in nearshore sediments in the vicinity of urban and industrial regions. In Humber Bay and Toronto Harbour microplastic concentrations were consistently >500 particles per kg dry sediment. Maximum concentrations of ~28,000 particles per kg dry sediment were determined in Etobicoke Creek. The microplastic particles were primarily fibres and fragments <2mm in size. Both low- and high-density plastics were identified using Raman spectroscopy. We provide a baseline for future monitoring and discuss potential sources of microplastics in terms of how and where to implement preventative measures to reduce the contaminant influx. Although the impacts of microplastics contamination on ecosystem health and functioning is uncertain, understanding, monitoring and preventing further microplastics contamination in Lake Ontario and the other Great Lakes is crucial., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Organic flame retardants (OFRs) such as polybrominated diphenyl ethers (PBDEs) and novel halogenated flame retardants (NHFRs) are ubiquitous, persistent, and bioaccumulative contaminants that have been used in consumer goods to slow combustion. In this study, polyethylene passive samplers (PEs) were deployed throughout the lower Great Lakes (Lake Erie and Lake Ontario) to measure OFRs in air and water, calculate air-water exchange fluxes, and investigate spatial trends. Dissolved Σ12BDE was greatest in Lake Ontario near Toronto (18 pg/L), whereas gaseous Σ12BDE was greatest on the southern shoreline of Lake Erie (11 pg/m(3)). NHFRs were generally below detection limits. Air-water exchange was dominated by absorption of BDEs 47 and 99, ranging from -964 pg/m(2)/day to -30 pg/m(2)/day. Σ12BDE in air and water was significantly correlated with surrounding population density, suggesting that phased-out PBDEs continued to be emitted from population centers along the Great Lakes shoreline in 2012. Correlation with dissolved Σ12BDE was strongest when considering population within 25 km while correlation with gaseous Σ12BDE was strongest when using population within 3 km to the south of each site. Bayesian kriging was used to predict dissolved Σ12BDE over the lakes, illustrating the utility of relatively highly spatially resolved measurements in identifying potential hot spots for future study.

Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011-2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air-water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L(-1) in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L(-1) in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7-634 pg m(-3) across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air-water exchange fluxes of Σ7PCBs ranged from -2.4 (±1.9) ng m(-2) day(-1) (deposition) in Sheffield (site E03) to 9.0 (±3.1) ng m(-2) day(-1) (volatilization) in Niagara (site On05). Net volatilization of PCBs was the primary trend across most sites and periods. Almost half of variation in air-water exchange fluxes was attributed to the difference in aqueous concentrations of PCBs. Uncertainty analysis in fugacity ratios and mass fluxes in air-water exchange of PCBs indicated that PCBs have reached or approached equilibrium only at the eastern Lake Erie and along the Canadian shore of Lake Ontario sites, where air-water exchange fluxes dominated atmospheric concentrations.

The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

Microplastics are a source of environmental pollution resulting from degradation of plastic products and spillage of resin pellets. We report the amounts of microplastics from various sites of Lake Ontario and evaluate their potential for preservation in the sediment record. A total of 4635 pellets were sampled from the Humber Bay shoreline on three sampling dates. Pellet colours were similar to those from the Humber River bank, suggesting that the river is a pathway for plastics transport into Lake Ontario. Once in the lake, high density microplastics, including mineral-polyethylene and mineral-polypropylene mixtures, sink to the bottom. The minerals may be fillers that were combined with plastics during production, or may have adsorbed to the surfaces of the polymers in the water column or on the lake bottom. Based on sediment depths and accumulation rates, microplastics have accumulated in the offshore region for less than 38 years. Their burial increases the chance of microplastics preservation. Shoreline pellets may not be preserved because they are mingled with organic debris that is reworked during storm events., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The dechlorane family of flame retardants, which includes Mirex (also known as Dechlorane), Dechlorane Plus (DP), and Dechloranes (Dec) 602, 603, and 604, were manufactured at a facility along the Niagara River, upstream of Lake Ontario. Some of these compounds remain in use. In a previous study, we found Mirex and Dec602 to have greater bioaccumulation potentials than Dec604 and DP based on calculated biota-sediment accumulation factors (BSAFs). In this study, analogues of Dec604, containing fewer bromines and mixed substitutions of bromine and chlorine, were identified in Lake Ontario sediment and fish using high and ultrahigh resolution mass spectrometric techniques. The tribromo-Dec604 (Br3Dec604) analogue, known as Dechlorane 604 Component B (Dec604 CB), was present in lake trout and whitefish at concentrations of 10-60 ng/g lipid weight, approximately 50-200 times greater than concentrations measured for Dec604. In addition, BrDec604 and Br2Dec604 analogues, and mixed Br2Cl2Dec604, Br3ClDec604, Br2ClDec604, and BrCl2Dec604 analogues were also present. We have shown that solutions of Dec604 and Dec604 CB exposed to UV-light undergo photodebromination and give rise to the analogues found in sediment and fish. Dec604 CB and other lesser halogenated analogues of Dec604 show greater bioaccumulation potentials than Dec604, Dec602 and DP, based on BSAFs, which highlight the need to consider likely impurities and degradation products in the assessment of persistent, bioaccumulative, and toxic compounds.

Between July 9-12, 1997, at least 400 tonnes of polyvinyl chloride (PVC) were consumed in a fire at the Plastimet Inc. plastics recycling facility in Hamilton, Ontario, Canada. This led to the release of contaminants, including highly toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). This study re-examines a composite soil sample collected shortly after the fire using state-of-the-art FT-ICR (Fourier transform ion cyclotron resonance) and GC × GC-TOF (comprehensive two-dimensional gas chromatography-time-of-flight) mass spectrometry. The FT-ICR experiments led to the identification of approximately 150 molecular formulas, corresponding to chlorinated and mixed chloro/bromo compounds. The majority of these are halogenated polycyclic aromatic hydrocarbons (halo-PAHs), including highly substituted (e.g., C14HCl9 and C16HCl9) and high molecular weight (e.g., C28H12Cl4) Cl-PAHs that have not been reported previously in environmental samples. Complementary GC × GC-TOF experiments resolved individual halo-PAHs, some of which were confirmed with available standards. The concentrations of the most abundant halo-PAH groups, C14H8Cl2 (22 μg/g) and C16H8Cl2 (20 μg/g) are much higher than reported dioxin values and comparable to the corresponding PAH groups C14H10 (12 μg/g) and C16H10 (19 μg/g). The high abundance of the halo-PAHs identified in this study highlights the need for further investigation into their environmental occurrence and risk.

This work describes a single and fast approach using a filtering script as a means of prioritizing sample processing of data acquired by GC×GC-TOF MS for the identification of potentially novel persistent and bioaccumulative halogenated chemicals. The proposed script is based on the recognition of a generic halogenated isotope cluster pattern that allows for the simultaneous detection of chlorinated, brominated, or mixed halogen-substituted compounds in a single classification. Once developed, the script was applied to the identification of organohalogens in stream sediments collected across the southern region of Ontario (Canada). Classified peaks were first compared with available analytical standards and reference libraries to confirm the known chemicals. Unknown potential persistent organic pollutants (POPs) were evaluated for occurrence within the samples and high resolution mass spectrometry was used in order to identify some of the most prevalent compounds in the samples and resulting in the identification of three decachlorinated dechlorane analogs (C18H14Cl10), two undecachlorinated dechlorane species (C18H13Cl11), and a novel mixed chloro/bromo-carbazole (C12H5NCl2Br2) in a number of sediments analyzed. Relative peak abundances of these unknown halogenated compounds were in the same order of magnitude or slightly higher than levels observed for conventional POPs detected in the samples.

Loadings from Toronto, Canada to Lake Ontario were quantified and major sources and pathways were identified, with the goal of informing opportunities for loading reductions. The contaminants were polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs) and polycyclic musks (PCMs). Loadings were calculated from measured concentrations for three major pathways: atmospheric processes, tributary runoff, and wastewater treatment plant (WWTP) effluents. Although atmospheric deposition to the Great Lakes has received the greatest attention, this was the dominant loading pathway for PCBs only (17 ± 5.3 kg/y or 66% of total loadings). PCB loadings reflected elevated urban PCB air concentrations due to, predominantly, primary emissions. These loadings contribute to consumption advisories for nearshore fish. PBDE loadings to the lake, again from mainly primary emissions, were 48% (9.1 ± 1.3 kg/y) and 42% (8.0 ± 5.7 kg/y) via tributaries and WWTPs, respectively, consistent with emissions deposited and subsequently washed-off of urban surfaces and emissions to the sewage system. PAHs loadings of 1600 ± 280 kg/y (71%) from tributaries were strongly associated with vehicle transportation and impervious surfaces. PCM loadings were 83% (±140 kg/y) from WWTP final effluent, reflecting their use in personal care products. Opportunities for source reduction lie in reducing the current inventories of in-use PCBs and PBDE-containing products, reducing vehicle emissions of PAHs and use of PAHs in the transportation network (e.g., pavement sealants), and improving wastewater treatment technology.

In Canada, perfluoroalkyl acids (PFAAs) have been the focus of several monitoring programs and research and surveillance studies. Here, we integrate recent data and perform a multi-media assessment to examine the current status and ongoing trends of PFAAs in Canada. Concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and other long-chain perfluorocarboxylates (PFCAs) in air, water, sediment, fish, and birds across Canada are generally related to urbanization, with elevated concentrations observed around cities, especially in southern Ontario. PFOS levels in water, fish tissue, and bird eggs were below their respective Draft Federal Environmental Quality Guidelines, suggesting there is low potential for adverse effects to the environment/organisms examined. However, PFOS in fish and bird eggs tended to exceed guidelines for the protection of mammalian and avian consumers, suggesting a potential risk to their wildlife predators, although wildlife population health assessments are needed to determine whether negative impacts are actually occurring. Long-term temporal trends of PFOS in suspended sediment, sediment cores, Lake Trout (Salvelinus namaycush), and Herring Gull (Larus argentatus) eggs collected from Lake Ontario increased consistently from the start of data collection until the 1990s. However, after this time, the trends varied by media, with concentrations stabilizing in Lake Trout and Herring Gull eggs, and decreasing and increasing in suspended sediment and the sediment cores, respectively. For PFCAs, concentrations in suspended sediment, sediment cores, and Herring Gulls generally increased from the start of data collection until present and concentrations in Lake Trout increased until the late 1990s and subsequently stabilized. A multimedia comparison of PFAA profiles provided evidence that unexpected patterns in biota of some of the lakes were due to unique source patterns rather than internal lake processes. High concentrations of PFAAs in the leachate and air of landfill sites, in the wastewater influent/effluent, biosolids, and air at wastewater treatment plants, and in indoor air and dust highlight the waste sector and current-use products (used primarily indoors) as ongoing sources of PFAAs to the Canadian environment. The results of this study demonstrate the utility of integrating data from different media. Simultaneous evaluation of spatial and temporal trends in multiple media allows inferences that would be impossible with data on only one medium. As such, more co-ordination among monitoring sites for different media is suggested for future sampling, especially at the northern sites. We emphasize the importance of continued monitoring of multiple-media for determining future responses of environmental PFAA concentrations to voluntary and regulatory actions., (Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.)

Mass defect is the difference between the nominal and exact mass of a chemical element or compound. An intrinsic property of polyhalogenated molecules is a uniquely negative mass defect, which readily distinguishes halogenated from non-halogenated compounds in a complex mass spectrum and can be visualized by constructing a mass defect plot. This study demonstrates the utility of the mass defect plot as a powerful tool to screen gas-chromatography (ultra)high-resolution mass spectrometry data for potentially toxic and bioaccumulative halogenated compounds in a Lake Ontario lake trout, an apex species in the Great Lakes environment. Our results indicate that the sample is contaminated with polychlorinated biphenyls, terphenyls, diphenylethers, as well as other chlorinated pesticides and flame retardants that are regulated and routinely analyzed by traditional target analyses. However, the mass defect plot also displays peaks which could be traced to the presence of as yet undiscovered contaminants. These include chlorinated polycyclic aromatic hydrocarbons as well as mixed halogenated analogues of the flame retardant Dechlorane 604. The identity of the latter class of compounds is supported by experiments with genuine standards.

Land use regression (LUR), a geographic information system (GIS), and measured air concentrations were used to identify potential sources of semivolatile organic contaminants (SVOCs) within an urban/suburban region, using Toronto, Canada as a case study. Regression results suggested that air concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and polycyclic musks (PCMs) were correlated with sources at a scale of <5 km. LUR was able to explain 73-90% of the variability in PCBs and PCMs, and 36-89% of PBDE and PAH variability, suggesting that the latter have more spatially complex emission sources, particularly for the lowest and highest molecular weight compounds/congeners. LUR suggested that ~75% of the PCB air concentration variability was related to the distribution of PCBs in use/storage/building sealants, ~60% of PBDE variability was related to building volume, ~55% of the PAH variability was related to the distribution of transportation infrastructure, and ~65% of the PCM variability was related to population density. Parameters such as population density and household income were successfully used as surrogates to infer sources and air concentrations of SVOCs in Toronto. This is the first application of LUR methods to explain SVOC concentrations.

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

During the course of our studies of in-use chlorinated flame retardants, such as Dechlorane Plus(®) and Dechloranes 602 and 604, blubber of beluga whales from the Canadian Arctic and lake trout and whitefish from the North American Great Lakes were found to contain two novel dechlorination products of Dechlorane 602 (Dec602). The structures of these compounds were characterized by experiments performed using both gas chromatography-high resolution mass spectrometry and Fourier transform mass spectrometry with a prepared technical mixture of monohydro and dihydroDec602 derivatives. These Dec602 derivatives are analogous to the well-known monohydro and dihydro photochemical degradation products of Mirex. The ratio of the two monohydroDec602 diastereomers varied between Lake Ontario fish and those from the upper lakes, but only one isomer was found in Arctic beluga, indicating that one isomer is either more stable or more bioaccumulative. Dechlorane Plus(®), Dec603, and Dec 604 were not detected in Arctic beluga, but Dec602 and its monohydroDec602 derivative were measured in approximately equal concentrations, ranging from 25 to 300 pg/g lipid. In Great Lakes fish, concentrations of the monohydroDec602 derivatives were also close to those of Dec602, ranging from 2 to 67 ng/g lipid and were greatest in Lake Ontario. This study reports on the first measurements of dechlorane-related compounds in Arctic biota and the first detection of monohydroDec602 degradation products and their accumulation in biota.

Lake Ontario water and sediment collected from tributary, nearshore, and open lake sites were analyzed for perfluoroalkyl substances (PFASs), namely perfluoroalkyl carboxylic acids (PFCAs, F(CF(2))(n)CO(2)(-); n=6-11,13) and perfluoroalkane sulfonic acids (PFSAs, F(CF(2))(n)SO(3)(-); n=6,8,10). Survey results of surface sediment and water indicated that shorter chained PFASs were predominant in and near urban/industrial area watersheds, while longer chained PFASs were predominant in fine-grained sediment from major depositional basins. Niagara River suspended solids (1981-2006) demonstrated temporal trends that may have been influenced by recent changes in North American production and use of PFASs. Perfluorooctane sulfonate (PFOS) reached a peak concentration in 2001 of 1.1 ng/g, followed by a decrease from 2001 to 2006 (half-life=9 years). Perfluorooctanoic acid (PFOA) increased from 2001 to 2006 (doubling time= 2 years) reaching a peak concentration of 0.80 ng/g. In contrast, three sediment cores from western, central, and eastern Lake Ontario showed increasing temporal trends to surface sediment for all PFASs. PFOA and PFOS concentrations increased from 1988 to 2004 (doubling time= ~ 4 years) in the western Lake Ontario core. The observed variations in temporal trends from different environmental compartments may be a result of the physico-chemical properties of PFASs, ongoing emissions, and the environmental transformation and degradation of PFAS precursor compounds., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

The distributions of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Toronto, Canada and the surrounding suburban/rural area were examined. A series of temporally- and spatially-distributed air samples was collected over a 1-year period with a high-volume active air sampler at one downtown site and polyurethane foam passive air samplers at 19 sites. Passive sampler air concentrations of ΣPAHs ranged from 0.27 to 51 ng/m³. Concentrations of ΣPCBs ranged from 6.0 to 1300 pg/m³, and concentrations of ΣPBDEs ranged from 0.47 to 110 pg/m³. All compounds exhibited the highest concentrations in the urban core, and lowest concentrations in the surrounding rural areas, however the exact ratio depended on location since concentrations varied considerably within the city. Results from the application of a radial dilution model highlighted the influence of the central business district (CBD) of the city as a source of contaminants to the surrounding environment, however the radial dilution comparison also demonstrated that sources outside the CBD have a significant influence on regional contaminant concentrations. A strong relationship between temperature and partial pressure of the gas-phase PCBs, low molecular weight PBDEs and less-reactive PAHs suggested that their dominant emissions originated from temperature-controlled processes such as volatilization from local sources of PCBs, PAHs and PBDEs at warm temperatures, condensation and deposition of emissions at cold temperatures, and ventilation of indoor air with elevated concentrations. The relationship between temperature and atmospheric PAH concentrations varied along the urban-rural gradient, which suggested that in highly urbanized areas, such as downtown Toronto, temperature-related processes have a significant impact on air concentrations, whereas winter emissions from domestic heating have a greater influence in areas with less impervious surface coverage., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Temporal trends and seasonal variation of Dechloranes (Dec) 602, 603, 604, and Chlordene Plus (CP) in Niagara River suspended sediment, a Lake Ontario sediment core, and Lake Ontario lake trout were investigated, with Mirex and Dechlorane Plus (DP) included for comparison. Temporal concentration trends were generally consistent in each of the media for all compounds with the lowest concentrations observed in or after the late 1990s. In Niagara River suspended sediments, all compounds showed seasonal variation over a year with distinct profiles observed. The relative concentration patterns observed were total DP > Mirex > Dec 602 and Dec 604 > Dec 603 > CP in suspended sediments and sediment cores, whereas Mirex was highest in lake trout, followed by Dec 602 and DP. Dec 602 concentrations were 50 to 380 times greater than those of DP in lake trout, indicating Dec 602 has a greater bioaccumulation potential. The estimated biota-sediment accumulation factor (BSAF) for Dec 602 was much greater than for DP in Lake Ontario, and was greater than those calculated for PBDEs, indicating that assessment of some dechlorane compounds is merited if use is ongoing or planned.

The effect of solution pH and levels of dissolved organic matter (DOM) on the sampling rates for model pharmaceuticals and personal care products (PPCPs) and endocrine disrupting substance (EDS) by polar organic chemical integrative samplers (POCIS) was investigated in laboratory experiments. A commercially available POCIS configuration containing neutral Oasis HLB (hydrophilic-lipophilic balance) resin (i.e. pharmaceutical POCIS) and two POCIS configurations prepared in-house containing MAX and MCX anion and cation exchange resins, respectively were tested for uptake of 21 model PPCPs and EDS, including acidic, phenolic, basic and neutral compounds. Laboratory experiments were conducted with dechlorinated tap water over a pH range of 3, 7 and 9. The effects of DOM were studied using natural water from an oligotrophic lake in Ontario, Canada (i.e. Plastic Lake) spiked with different amounts of DOM (the concentration of dissolved organic carbon ranged from 3 to 5mgL(-1) in uptake experiments). In experiments with the commercial (HLB) POCIS, the MCX-POCIS and the MAX-POCIS, the sampling rates generally increased with pH for basic compounds and declined with pH for acidic compounds. However, the sampling rates were relatively constant across the pH range for phenols with high pKa values (i.e. bisphenol A, estrone, estradiol, triclosan) and for the neutral pharmaceutical, carbamazepine. Thus, uptake was greatest when the amount of the neutral species in solution was maximized relative to the ionized species. Although the solution pH affected the uptake of some model ionic compounds, the effect was by less than a factor of 3. There was no significant effect of DOM on sampling rates from Plastic Lake. However, uptake rates in different aqueous matrixes declined in the order of deionized water>Plastic Lake water>dechlorinated tap water, so other parameters must affect uptake into POCIS, although this influence will be minor. MAX-POCIS and MCX-POCIS showed little advantage over the commercial POCIS configuration for monitoring in natural waters., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Although the two flame retardants 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) and 1,2,5,6-tetrabromocyclooctane (TBCO) have been widely used, a selective instrumental method of analysis for these compounds has not been developed to date. In this study, we demonstrate the feasibility to utilize liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the separation and analysis of α- and β-TBCO and α-, β-, γ-, and δ-TBECH. Acetone was initially used in a tetrahedron solvent system for LC optimization. A simple isocratic elution allowed near-baseline separation of these compounds. Different ionization approaches and mechanisms were investigated. The mass spectrometric transition of [M + O(2)](-) => Br(-) (459.8 => 78.9) was a selective detection method for the target analytes. Good instrument detection limits (5 pg for γ-/δ-TBECH, 125 pg for α-/β-TBECH, and 30 pg for α-/β-TBCO with 2.0 µL injection) were obtained. Excellent linearity up to 50 ng/µL (R(2) >0.999) was also achieved. This method has been applied to environmental samples (surface water) for screening purposes with recoveries ranging from 76-92% (CV%: 5-8%). This method shows significant improvement over previous methods., (Copyright © 2011 John Wiley & Sons, Ltd.)

Liquid chromatography/atmospheric pressure photoionization tandem mass spectrometry (LC/APPI-MS/MS) was investigated as an instrumental method for the analysis of the halogenated norbornene flame retardants, Mirex, Dechloranes 602, 603, 604, and Dechlorane Plus (DP). The LC separation was optimized by screening a variety of stationary and mobile phases, resulting in a short LC separation time of 5 min. Different atmospheric pressure ionization approaches were examined including electrospray ionization, atmospheric pressure chemical ionization, and APPI, each with and without post-column addition. APPI without post-column addition was chosen for providing the best ionization response. The optimized LC/APPI-MS/MS approach resulted in instrument detection limits ranging between 25 and 50 pg. Good linearity was also achieved (up to 25.0 ng/µL; R >0.999). The method was applied to extracts of environmental samples including surface water, fish and sediments for screening purposes, and the results agreed well with those obtained by gas chromatography/mass spectrometry., (Copyright © 2011 John Wiley & Sons, Ltd.)

A chlorinated compound (Chlordene Plus, CP), structurally related to Dechloranes (Dec) 602, 603, 604, and Dechlorane Plus (DP), was identified, and concentrations and spatial trends of Dec 602, 603, 604, CP, and DP in tributary sediments of the Laurentian Great Lakes are reported. The dechloranes were widely detected with their concentrations varying considerably across the Great Lakes basin. Spatial trends of Dec 602, 604, and DP in Canadian tributary sediments were similar to that of BDE 209, which suggested these flame retardant chemicals in tributaries were associated with industrial and urban areas. The highest concentrations of Dec 602, 604, and DP observed in tributaries of the Niagara River confirmed that past or ongoing manufacturing of these compounds at plants along the river were important sources to Lake Ontario. Dec 603 was detected in technical products of aldrin and dieldrin, and its spatial trend was consistent with historic pesticide usage. Similarly, CP was detected in technical products of chlordene and chlordane, and it was found in higher concentrations in sediments near urban areas, possibly related to past chlordane use in home termite control.

The uptake of polar organic contaminants into polar organic chemical integrative samplers (POCIS) varies with environmental factors, such as water flow rate. To evaluate the influence of water flow rate on the uptake of contaminants into POCIS, flow-controlled field experiments were conducted with POCIS deployed in channel systems through which treated sewage effluent flowed at rates between 2.6 and 37 cm/s. Both pharmaceutical POCIS and pesticide POCIS were exposed to effluent for 21 d and evaluated for uptake of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting substances (EDS). The pesticide POCIS had higher uptake rates for PPCPs and EDS than the pharmaceutical POCIS, but there are some practical advantages to using pharmaceutical POCIS. The uptake of contaminants into POCIS increased with flow rate, but these effects were relatively small (i.e., less than twofold) for most of the test compounds. There was no relationship observed between the hydrophobicity (log octanol/water partition coefficient, log K(OW)) of model compounds and the effects of flow rate on the uptake kinetics by POCIS. These data indicate that water flow rate has a relatively minor influence on the accumulation of PPCPs and EDS into POCIS., (© 2010 SETAC.)