Size-Resolved Identification and Quantification of Micro/Nanoplastics in Indoor Air Using Pyrolysis Gas Chromatography-Ion Mobility Mass Spectrometry.

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/m3, respectively. In the private residence, the estimated concentrations were 24 ± 3 and 16 ± 2 µg/m3. 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.

Microplastic contamination in Great Lakes fish.

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.

Contaminación por Microplásticos en Peces de los Grandes Lagos Resumen Los ecosistemas de agua dulce, generalmente contiguos a poblaciones humanas y más contaminados en relación con los ecosistemas marinos adyacentes, son vulnerables a la contaminación por microplásticos. Muestreamos siete especies de peces del Lago Ontario y del Lago Superior y analizamos sus tractos gastrointestinales (GI) para cuantificar los microplásticos ingeridos, además de otras partículas antropogénicas. Un subconjunto de las micropartículas fue analizado químicamente para confirmar los tipos de polímero y los orígenes antropogénicos. Documentamos la concentración más alta de microplásticos y de otras micropartículas antropogénicas jamás reportada en peces óseos. Encontramos 12,442 micropartículas antropogénicas en 212 peces (ocho especies) del Lago Ontario, 943 en 50 peces (una especie) en el Río Humber y 30,094 en 119 peces (siete especies) del Lago Superior. Los peces del Lago Ontario tuvieron la mayor abundancia promedio de micropartículas antropogénicas en sus tractos GI (59 partículas/pez [DS 104]), con hasta 915 micropartículas en un solo pez. Los peces del Lago Superior tuvieron un promedio [DS] de 26 [74] partículas/pez y los peces del Río Humber tuvieron 19 [14] partículas/pez. La mayoría de las partículas eran microfibras. En general, ≥90% de las partículas eran antropogénicas, de las cuales el 35-39% eran microplásticos. El polietileno (24%), el tereftalato de polietileno (20%) y el polipropileno (18%) fueron los microplásticos más comunes. La ingesta de partículas antropogénicas tuvo una diferencia significativa entre las especies del Lago Ontario (p < 0.05) y la abundancia de las partículas antropogénicas incrementó conforme aumentó la longitud de los peces en el Lago Ontario (ρ = 0.62). Aunque no podemos extrapolar la concentración de microplásticos en el agua y los sedimentos para estos peces, la abundancia relativamente alta de microplásticos en los tractos GI de los peces sugiere que la exposición ambiental puede estar por encima del umbral de concentraciones para el riesgo.

Nontargeted Screening Using Gas Chromatography-Atmospheric Pressure Ionization Mass Spectrometry: Recent Trends and Emerging Potential.

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.

Determination of Halogenated Flame Retardants Using Gas Chromatography with Atmospheric Pressure Chemical Ionization (APCI) and a High-Resolution Quadrupole Time-of-Flight Mass Spectrometer (HRqTOFMS).

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 (R2 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.

20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

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.

Hidden plastics of Lake Ontario, Canada and their potential preservation in the sediment record.

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.

Identification of the halogenated compounds resulting from the 1997 Plastimet Inc. fire in Hamilton, Ontario, using comprehensive two-dimensional gas chromatography and (ultra)high resolution mass spectrometry.

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.

Identification and determination of the dechlorination products of Dechlorane 602 in Great Lakes fish and Arctic beluga whales by gas chromatography-high resolution mass spectrometry.

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.

Hexachlorocyclohexanes (HCHs) in the Canadian Archipelago. 2. Air-water gas exchange of alpha- and gamma-HCH.

Air and water were sampled in the Canadian Archipelago during summer on the Tundra Northwest 1999 (TNW-99) expedition and air was sampled at Resolute Bay (RB), Nunavut, to determine the gas exchange of alpha- and gamma-hexachlorocyclohexanes (HCHs) and the enantiomers of alpha-HCH. Air concentrations of sigmaHCH during TNW-99 and at RB were similar, averaging 55 and 53 pg m(-3), respectively. The net gas exchange direction was volatilization for alpha-HCH and near equilibrium or deposition for gamma-HCH, whereas actual fluxes depended on the fraction of open water. Enantiomer fractions, EF = (+)/[(+) + (-)] of alpha-HCH in air sampled from shipboard were significantly correlated to those in surface water for events with >90% open water, but were closer to racemic and not correlated to EFs in water for events with 0-50% open water. Levels of alpha-HCH in air at RB averaged 37 +/- 9 pg m(-3) from June to early July, and EFs were close to racemic (0.496 +/- 0.004). In mid-July the ice pack broke up around RB. From this point through August, air concentrations increased significantly to 53 +/- 5 pg m(-3), and the mean EF decreased significantly to 0.483 +/- 0.009. Air concentrations of gamma-HCH at RB did not differ significantly before (8.0 +/- 3.7 pg m(-3)) and after (6.6 +/- 0.76 pg m(-3)) ice breakup. Results show that alpha-HCH enantiomers are sensitive tracers for following the impact of ice cover loss on gas exchange in the Arctic.

Gas-particle partitioning of polychlorinated naphthalenes and non- and mono-ortho-substituted polychlorinated biphenyls in arctic air.

Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphthalenes (PCNs) and non- and mono-ortho PCBs in arctic air by regressing observed gas-particle partition coefficients, K(P), at Alert and Dunai in the high Arctic with temperature-adjusted experimental vapor pressures (p(L) degrees ) and octanol-air partition coefficients (K(OA)). Slopes were near -0.5 and 0.5 for log p(L) degrees and log K(OA), respectively, at both sites, indicating that aerosol characteristics and partitioning processes were similar at the two sites. The K(OA) absorption model provided an adequate estimate of the percentage of PCNs and non-/mono-ortho PCBs associated with particulate matter, based on fraction of organic matter (f(OM)) ranging from 0.074 to 0.12, compared to the Junge-Pankow adsorption model, which slightly over-estimated the distribution on particles. There were no indications that partitioning to soot carbon influences the observed gas-particle distribution for PCNs and non-/mono-ortho PCBs in arctic air as has been observed for PAHs in recent studies at temperate locations.

Spatial distribution of polychlorinated naphthalenes in air over the Great Lakes and air-water gas exchange in Lake Ontario.

High-volume air samples were collected during research cruises of Lake Superior in August 1996 and May 1997 and of Lake Ontario (North America) in July and September 1998 and June 2000 and analyzed for polychlorinated naphthalenes (PCNs). Levels of tetra- to octachloronaphthalene (sigmaPCN) varied spatially, with mean values (+/-SD) of 1.78 +/- 0.74 and 1.46 +/- 1.07 pg m(-3) for Lake Superior in 1996 and 1997, respectively, and of 5.53 +/- 2.19 and 5.60 +/- 2.24 pg m(-3) for Lake Ontario in 1998 and 2000, respectively. Evaporative sources were predominant, although combustion marker congeners such as tetrachloronaphthalenes 44 and 29 and pentachloronaphthalene 54 were present in most samples and were enhanced relative to technical PCN mixtures. The sigmaPCN concentrations were higher in Lake Ontario samples collected in the western half of the lake and when winds were from the west. Greater proportions of the population and industrial areas are located around the western part of Lake Ontario. Water-air fugacity ratios, calculated from air and water samples collected in June 2000, indicate that the trichloronaphthalenes are volatilizing from Lake Ontario, whereas the tetrachloronaphthalenes are close to equilibrium and the net deposition of tetrachloronaphthalenes can occur when the urban air plume influences levels over the lake.

Chiral pesticides in soil and water and exchange with the atmosphere.

The enantiomers of chiral pesticides are often metabolised at different rates in soil and water, leading to nonracemic residues. This paper reviews enantioselective metabolism of organochlorine pesticides (OCPs) in soil and water, and the use of enantiomers to follow transport and fate processes. Residues of chiral OCPs and their metabolites are frequently nonracemic in soil, although exceptions occur in which the OCPs are racemic. In soils where enantioselective degradation and/or metabolite formation has taken place, some OCPs usually show the same degradation preference--e.g., depletion of (+)trans-chlordane (TC) and (-)cis-chlordane (CC), and enrichment of the metabolite (+)heptachlor exo-epoxide (HEPX). The selectivity is ambivalent for other chemicals; preferential loss of either (+) or (-)o,p-DDT and enrichment of either (+) or (-)oxychlordane (OXY) occurs in different soils. Nonracemic OCPs are found in air samples collected above soil which contains nonracemic residues. The enantiomer profiles of chlordanes in ambient air suggests that most chlordane in northern Alabama air comes from racemic sources (e.g., termiticide emissions), whereas a mixture of racemic and nonracemic (volatilisation from soil) sources supplies chlordane to air in the Great Lakes region. Chlordanes and HEPX are also nonracemic in arctic air, probably the result of soil emissions from lower latitudes. The (+) enantiomer of alpha-hexachlorocyclohexane (alpha-HCH) is preferentially metabolised in the Arctic Ocean, arctic lakes and watersheds, the North American Great Lakes, and the Baltic Sea. In some marine regions (the Bering and Chukchi Seas, parts of the North Sea) the preference is reversed and (-)alpha-HCH is depleted. Volatilisation from seas and large lakes can be traced by the appearance of nonracemic alpha-HCH in the air boundary layer above the water. Estimates of microbial degradation rates for alpha-HCH in the eastern Arctic Ocean and an arctic lake have been made from the enantiomer fractions (EFs) and mass balance in the water column. Apparent pseudo first-order rate constants in the eastern Arctic Ocean are 0.12 year(-1) for (+)alpha-HCH, 0.030 year(-1) for (-)alpha-HCH, and 0.037 year(-1) for achiral gamma-HCH. These rate constants are 3-10 times greater than those for basic hydrolysis in seawater. Microbial breakdown may compete with advective outflow for long-term removal of HCHs from the Arctic Ocean. Rate constants estimated for the arctic lake are about 3-8 times greater than those in the ocean.