An improved method for the analysis of volatile polyfluorinated alkyl substances in environmental air samples

Rapid, efficient, and green analytical technique for determination of fluorotelomer alcohol in water by stir bar sorptive extraction

Fluorotelomer alcohols (FTOHs) are one of the major classes of per- and polyfluoroalkyl substances (PFAS). Due to their potential toxicity, persistence, and ubiquitous presence in the environment, some common PFAS are voluntarily phased out; while FTOHs are used as alternatives to conventional PFAS. FTOHs are precursors of perfluorocarboxylic acids (PFCAs) and therefore they are commonly detected in water matrices, which eventually indicate PFAS contamination in drinking water supplies and thus a potential source of human exposure. Even though studies have been conducted nationwide to evaluate the degree of FTOHs in the water environment, robust monitoring is lacking because of the unavailability of simple and sustainable analytical extraction and detection methods. To fill the gap, we developed and validated a simple, rapid, minimal solvent use, no clean-up, and sensitive method for the determination of FTOHs in water by stir bar sorptive extraction (SBSE) coupled with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Three commonly detected FTOHs (6:2 FTOH, 8:2 FTOH, and 10:2 FTOH) were selected as the model compounds. Factors such as extraction time, stirring speed, solvent composition, salt addition, and pH were investigated to achieve optimal extraction efficiency. This "green chemistry" based extraction provided good sensitivity and precision with low method limits of detection ranging from 2.16 ng/L to 16.7 ng/L and with an extraction recovery ranging 55%-111%. The developed method were tested on tap water, brackish water, and wastewater influent and effluent. 6:2 FTOH and 8:2 FTOH were detected in two wastewater samples at 78.0 and 34.8 ng/L, respectively. This optimized SBSE-TD-GC-MS method will be a valuable alternative to investigate FTOHs in water matrices.

Method development for thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS/MS) analysis of trace level fluorotelomer alcohols emitted from consumer products

The scientific foundation for per- and polyfluoroalkyl substances (PFAS) measurements in water, soils, sediments, biosolids, biota, and outdoor air has rapidly expanded; however, there are limited efforts devoted to developing analytical methods to measure vapor-phase PFAS in indoor air. A gas chromatography-tandem mass spectrometry (GC-MS/MS) method coupled with thermal desorption (TD) sorbent tube analysis was developed to quantify trace levels of fluorotelomer alcohols (FTOHs) emitted from consumer products in the indoor environment. Method evaluation included determination of instrument detection limits (IDLs), quality assurance checks of target standards purchased from different vendors, sample loss during storage, and TD sorbent breakthrough with tubes coupled in-series. The IDLs for TD-GC-MS/MS analyses ranged from 0.07 - 0.09 ng/tube. No significant loss of FTOHs was observed during stability tests over 28 days with relative standard deviations (RSDs) of spiked TD tubes ranging from 3.1 - 7.7% and the RSDs of polypropylene copolymer vial storage of standard solutions ranging from 4.3 - 8.4%. TD tube breakthrough was minimal with recovered FTOHs in the second tubes <1% of the spiked concentrations in the first tubes with carrier gas volume up to 20 L. The method has been applied to determine FTOH emissions from three consumer products in micro-scale chambers. A liquid stone cleaner/sealer product contained the highest levels of 6:2, 8:2, and 10:2 FTOHs, while the mattress pad products contained lower levels of 8:2 and 10:2 FTOHs. The emission parameters, including the initial emission factors and first order decay rate constants, were obtained based on the experimental data. The developed methods are sensitive and specific for analysis of all four target FTOHs (4:2, 6:2, 8:2, 10:2 FTOHs) with chamber testing. The methods can be extended to indoor air sampling and could be applicable to ambient air sampling.

Biotransformation of 6:2 Fluorotelomer Thioether Amido Sulfonate in Aqueous Film-Forming Foams under Nitrate-Reducing Conditions

Despite the prevalence of nitrate reduction in groundwater, the biotransformation of per- and polyfluoroalkyl substances (PFAS) under nitrate-reducing conditions remains mostly unknown compared with aerobic or strong reducing conditions. We constructed microcosms under nitrate-reducing conditions to simulate the biotransformation occurring at groundwater sites impacted by aqueous film-forming foams (AFFFs). We investigated the biotransformation of 6:2 fluorotelomer thioether amido sulfonate (6:2 FtTAoS), a principal PFAS constituent of several AFFF formulations using both quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) and qualitative high-resolution mass spectrometry analyses. Our results reveal that the biotransformation rates of 6:2 FtTAoS under nitrate-reducing conditions were about 10 times slower than under aerobic conditions, but about 2.7 times faster than under sulfate-reducing conditions. Although minimal production of 6:2 fluorotelomer sulfonate and the terminal perfluoroalkyl carboxylate, perfluorohexanoate was observed, fluorotelomer thioether and sulfinyl compounds were identified in the aqueous samples. Evidence for the formation of volatile PFAS was obtained by mass balance analysis using the total oxidizable precursor assay and detection of 6:2 fluorotelomer thiol by gas chromatography-mass spectrometry. Our results underscore the complexity of PFAS biotransformation and the interactions between redox conditions and microbial biotransformation activities, contributing to the better elucidation of PFAS environmental fate and impact.

Detection and removal of poly and perfluoroalkyl polluting substances for sustainable environment

PFAs (poly and perfluoroalkyl compounds) are hazardous and bioaccumulative chemicals that do not readily biodegrade or neutralize under normal environmental conditions. They have various industrial, commercial, domestic and defence applications. According to the Organization for Economic Co-operation and Development, there are around 4700 PFAs registered to date. They are present in every stream of life, and they are often emerging and are even difficult to be detected by the standard chemical methods. This review aims to focus on the sources of various PFAs and the toxicities they impose on the environment and especially on humankind. Drinking water, food packaging, industrial areas and commercial household products are the primary PFAs sources. Some of the well-known treatment methods for remediation of PFAs presented in the literature are activated carbon, filtration, reverse osmosis, nano filtration, oxidation processes etc. The crucial stage of handling the PFAs occurs in determining and analysing the type of PFA and its remedy. This paper provides a state-of-the-art review of determination & tools, and techniques for remediation of PFAs in the environment. Improving new treatment methodologies that are economical and sustainable are essential for excluding the PFAs from the environment.

Simultaneous analysis of neutral and ionizable per- and polyfluoroalkyl substances in air

A new method is preliminarily validated for the simultaneous analysis of ionic and neutral per- and polyfluoroalkyl substances (PFASs) in both particulate and gaseous phases in air using a nanosampler-20 air sampler (NS20) composed of quartz fiber filters (QFFs), polyurethane foam (PUF) and artificial activated charcoal (GAIAC™). Perfluoroalkane sulfonamido ethanols (FOSEs) mainly remained in PUF, whereas the other neutral analytes were mainly found in GAIAC. Satisfactory recoveries were obtained for FOSEs, fluorotelomer alcohols (FTOHs), fluorotelomer iodides (FTIs), ranging fron 70%-120%, moderate recoveries were achieved for perfluorinated iodine alkanes (FIAs) and diiodofluoroalkanes (FDIAs), ranging from 50%-70%, while poor recoveries were found for perfluoroalkane sulfonamides (FOSAs). Breakthrough experiments revealed that almost all the target analytes were well trapped in GAIAC™, including the very volatile 4:2 FTOH. Applying to real sampling, our results showed that 6:2 and 8:2 FTOH were the most abundant species, with levels detected at 190 pg/m³ and 160 pg/m³. To the best of our knowledge, FDIAs were detected in ambient air for the first time at an average level of 8.3 pg/m³. Overall, the profiles observed from the real air samples reflected current industrial transition from longer chain to shorter chain in PFAS production. Our results revealed that the current method is promising for a more comprehensive understanding on the fates of PFASs in air.

A Critical Review of a Recommended Analytical and Classification Approach for Organic Fluorinated Compounds with an Emphasis on Per- and Polyfluoroalkyl Substances

Organic fluorinated compounds have been detected in various environmental media and biota. Some of these compounds are regulated locally (e.g., perfluorononanoic acid maximum contaminant level in drinking water by the New Jersey Dept. of Environmental Protection), nationally (e.g., perfluorooctanoic acid maximum acceptable concentration in drinking water by Health Canada), or internationally (e.g., Stockholm Convention on Persistent Organic Pollutants). Globally, regulators and researchers seek to identify the organic fluorinated compounds associated with potential adverse effects, bioaccumulation, mobility, and persistence to manage their risks, and, to understand the beneficial attributes they bring to products such as first responder gear, etc. Clarity is needed to determine the best analytical method for the goal of the analyses (e.g., pure research or analysis to determine the extent of an accidental release, monitoring groundwater for specific compounds to determine regulatory compliance, and establish baseline levels in a river of organic fluorinated substances associated with human health risk prior to a clean-up effort). Analytical techniques that identify organic fluorine coupled together with targeted chemical analysis will yield information sufficient to identify public health or environmental hazards. Integr Environ Assess Manag 2021;17:331-351. © 2020. W.L. Gore & Associates Inc. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A critical review of modeling Poly- and Perfluoroalkyl Substances (PFAS) in the soil-water environment

Due to their health effects and the recalcitrant nature of their CF bonds, Poly- and Perfluoroalkyl Substances (PFAS) are widely investigated for their distribution, remediation, and toxicology in ecosystems. However, very few studies have focused on modeling PFAS in the soil-water environment. In this review, we summarized the recent development in PFAS modeling for various chemical, physical, and biological processes, including sorption, volatilization, degradation, bioaccumulation, and transport. PFAS sorption is kinetic in nature with sorption equilibrium commonly quantified by either a linear, the Freundlich, or the Langmuir isotherms. Volatilization of PFAS depends on carbon chain length and ionization status and has been simulated by a two-layer diffusion process across the air water interface. First-order kinetics is commonly used for physical, chemical, and biological degradation processes. Uptake by plants and other biota can be passive and/or active. As surfactants, PFAS have a tendency to be sorbed or concentrated on air-water or non-aqueous phase liquid (NAPL)-water interfaces, where the same three isotherms for soil sorption are adopted. PFAS transport in the soil-water environment is simulated by solving the convection-dispersion equation (CDE) that is coupled to PFAS sorption, phase transfer, as well as physical, chemical, and biological transformations. As the physicochemical properties and concentration vary greatly among the potentially thousands of PFAS species in the environment, systematic efforts are needed to identify models and model parameters to simulate their fate, transport, and response to remediation techniques. Since many process formulations are empirical in nature, mechanistic approaches are needed to further the understanding of PFAS-soil-water-plant interactions so that the model parameters are less site dependent and more predictive in simulating PFAS remediation efficiency.

Neutral polyfluoroalkyl and perfluoroalkyl substances in surface water and sediment from the Haihe River and Dagu Drainage Canal deserve more attention

Neutral polyfluoroalkyl and perfluoroalkyl substances (nPFASs) were detected in the surface water and sediment from the Haihe River (HR) and Dagu Drainage Canal (DDC), Tianjin, China. N-methyl perfluorooctane sulfonamide ethanol (MeFOSE) and N-ethyl perfluorooctane sulfonamide ethanol (EtFOSE) were the predominant nPFASs in surface water and sediment, which was different from the composition in air. The concentrations of ΣnPFASs in water from the HR (1.88-8.21 ng/L) were lower than those from the DDC (3.72-11.32 ng/L). Concentrations of ΣnPFASs were higher in the middle of the HR in the Dongli District due to industrial activity, whereas at lower reaches of the DDC, high ΣnPFAS concentrations might be due to effluent from wastewater treatment plants (WWTPs). The detection frequency in sediment (13.5%) was less than that in water (83%). The concentrations in sediment from the DDC (below limit of qualification (LOQ) to 5.58 ng/g) were higher than those from the HR (below LOQ to 2.46 ng/g). The distribution coefficient (log K_D) between water and sediment was calculated, and they were highly related to the compound structures. The contribution of nPFASs to nPFASs+PFAAs was up to 52% in sediment in the DDC, suggesting the importance of nPFASs in aquatic systems.

Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic)

A combination of local (i.e. firefighting training facilities) and remote sources (i.e. long-range transport) is assumed to be responsible for the occurrence of per- and polyfluoroalkyl substances (PFASs) in Svalbard (Norwegian Arctic). However, no systematic elucidation of local PFASs sources has been conducted yet. Therefore, a survey was performed aiming at identifying local PFAS pollution sources on the island of Spitsbergen (Svalbard, Norway). Soil, freshwater (lake, draining rivers), seawater, meltwater run-off, surface snow and coastal sediment samples were collected from Longyearbyen (Norwegian mining town), Ny-Ålesund (research facility) and the Lake Linnévatnet area (background site) during several campaigns (2014-2016) and analysed for 14 individual target PFASs. For background site (Linnévatnet area, sampling during April to June 2015), ΣPFAS levels ranged from 0.4 to 4 ng/L in surface lake water (n = 20). PFAS in meltwater from the contributing glaciers showed similar concentrations (~ 4 ng/L, n = 2). The short-chain perfluorobutanoate (PFBA) was predominant in lake water (60-80% of the ΣPFASs), meltwater (20-30%) and run-off water (40%). Long-range transport is assumed to be the major PFAS source. In Longyearbyen, five water samples (i.e. 2 seawater, 3 run-off) were collected near the local firefighting training site (FFTS) in November 2014 and June 2015, respectively. The highest PFAS levels were found in FFTS meltwater run-off (118 ng/L). Perfluorooctane sulfonic acid (PFOS) was the most abundant compound in the FFTS meltwater run-off (53-58% PFASs). At the research station Ny-Ålesund, seawater (n = 6), soil (n = 9) and freshwater (n = 10) were collected in June 2016. Low ΣPFAS concentrations were determined for seawater (5-6 ng/L), whereas high ΣPFAS concentrations were found in run-off water (113-119 ng/L) and soil (211-800 ng/g dry weight (dw)) collected close to the local FFTS. In addition, high ΣPFAS levels (127 ng/L) were also found in freshwater from lake Solvatnet close to former sewage treatment facility. Overall, at both FFTS-affected sites (soil, water), PFOS was the most abundant compound (60-69% of ΣPFASs). FFTS and landfill locations were identified as major PFAS sources for Svalbard settlements.

Per- and polyfluoroalkyl substances and fluorine mass balance in cosmetic products from the Swedish market: implications for environmental emissions and human exposure

Per- and polyfluoroalkyl substances (PFASs) are a diverse class of >4700 chemicals used in commercial products and industrial processes. Concerns surrounding PFASs are principally due to their widespread occurrence in humans and the environment and links to adverse health effects. One of the lesser known uses for PFASs is in cosmetic products (CPs) which come into contact with the skin (e.g. hair products, powders, sunblocks, etc.). In the present work, thirty-one CPs from five product categories (cream, foundation, pencil, powder and shaving foam) were analyzed for 39 PFASs by liquid chromatography-tandem mass spectrometry, as well as extractable organic fluorine (EOF) and total fluorine (TF) by combustion ion chromatography (CIC). This multi-platform approach enabled determination of the fraction of fluorine accounted for by known PFASs (i.e. fluorine mass balance). Foundations and powders contained 25 different PFASs with the most frequently detected being perfluorinated carboxylic acids (perfluoroheptanoic acid and perfluorohexanoic acid) and polyfluoroalkyl phosphate esters (PAPs). Σ14PAP concentrations up to 470 μg g-1 were measured in products listing mixtures of PAPs as an ingredient. For all samples, Σ39PFAS concentrations only explained a small fraction of the EOF and TF, pointing to the presence of unknown organic and/or inorganic fluorinated substances, including polymers. While creams, pencil and shaving foams did not contain measurable concentrations of any of the 39 PFASs targeted here, CIC revealed high to moderate TF content. Overall, these data highlight the need for further investigations into the occurrence of PFASs in CPs and their importance with regards to human and environmental exposure.

Evaluation of the impact of matrix effect on quantification of pesticides in foods by gas chromatography-mass spectrometry using isotope-labeled internal standards

The impact of the matrix effect in GC-MS quantification of pesticides in food using the corresponding isotope-labeled internal standards was evaluated. A spike-and-recovery study of nine target pesticides was first conducted using paste samples of corn, green soybean, carrot, and pumpkin. The observed analytical values using isotope-labeled internal standards were more accurate for most target pesticides than that obtained using the external calibration method, but were still biased from the spiked concentrations when a matrix-free calibration solution was used for calibration. The respective calibration curves for each target pesticide were also prepared using matrix-free calibration solutions and matrix-matched calibration solutions with blank soybean extract. The intensity ratio of the peaks of most target pesticides to that of the corresponding isotope-labeled internal standards was influenced by the presence of the matrix in the calibration solution; therefore, the observed slope varied. The ratio was also influenced by the type of injection method (splitless or on-column). These results indicated that matrix-matching of the calibration solution is required for very accurate quantification, even if isotope-labeled internal standards were used for calibration.

Endocrine disrupting chemicals in the atmosphere: Their effects on humans and wildlife

Endocrine disrupting chemicals (EDCs) are exogenous agents that interfere or disrupt the normal synthesis, secretion, transportation, binding and metabolism of natural hormones; eventually dysregulating homeostatic mechanisms, reproduction and development. They are emitted into the atmosphere during anthropogenic activities and physicochemical reactions in nature. Inhalation of these EDCs as particulate and gaseous vapors triggers their interaction with endocrine glands and exerts agonist or antagonists actions at hormone receptors. The endocrine disruption at nanogram levels of EDC's has gained concern in the last decade, due to infertility among men and women, early puberty, obesity, diabetes and cancer. Thus, the review explores the literature that addresses the major occurring EDCs in the atmosphere including phthalates, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants (BFRs), dioxins, alkylphenols (APs) and perfluorinated chemicals (PFCs). Sources, fate, half-life, mechanism, measured concentrations in air, bioaccumulation in tissues, laboratory exposures correlating to toxicological effects of these EDCs in humans and wildlife are discussed.

Estimating human exposure to PFOS isomers and PFCA homologues: the relative importance of direct and indirect (precursor) exposure

Contributions of direct and indirect (via precursors) pathways of human exposure to perfluorooctane sulfonic acid (PFOS) isomers and perfluoroalkyl carboxylic acids (PFCAs) are estimated using a Scenario-Based Risk Assessment (SceBRA) modelling approach. Monitoring data published since 2008 (including samples from 2007) are used. The estimated daily exposures (resulting from both direct and precursor intake) for the general adult population are highest for PFOS and perfluorooctanoic acid (PFOA), followed by perfluorohexanoic acid (PFHxA) and perfluorodecanoic acid (PFDA), while lower daily exposures are estimated for perfluorobutanoic acid (PFBA) and perfluorododecanoic acid (PFDoDA). The precursor contributions to the individual perfluoroalkyl acid (PFAA) daily exposures are estimated to be 11-33% for PFOS, 0.1-2.5% for PFBA, 3.7-34% for PFHxA, 13-64% for PFOA, 5.2-66% for PFDA, and 0.7-25% for PFDoDA (ranges represent estimated precursor contributions in a low- and high-exposure scenario). For PFOS, direct intake via diet is the major exposure pathway regardless of exposure scenario. For PFCAs, the dominant exposure pathway is dependent on perfluoroalkyl chain length and exposure scenario. Modelled PFOS and PFOA concentrations in human serum using the estimated intakes from an intermediate-exposure scenario are in agreement with measured concentrations in different populations. The isomer pattern of PFOS resulting from total intakes (direct and via precursors) is estimated to be enriched with linear PFOS (84%) relative to technical PFOS (70% linear). This finding appears to be contradictory to the observed enrichment of branched PFOS isomers in recent human serum monitoring studies and suggests that either external exposure is not fully understood (e.g. there are unknown precursors, missing or poorly quantified exposure pathways) and/or that there is an incomplete understanding of the isomer-specific human pharmacokinetic processes of PFOS, its precursors and intermediates.

Bioaccumulation of perfluoroalkyl substances by Daphnia magna in water with different types and concentrations of protein

Perfluoroalkyl substances (PFASs) are sometimes regarded as proteinophilic compounds, however, there is no research report about the effect of environmental protein on the bioaccumulation of PFASs in waters. In the present study we investigated influences of protein on the bioaccumulation of six kinds of PFASs by Daphnia magna in water; it included perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Two types of protein including bovine albumin from animal and soy peptone from plant were compared and the effects of protein concentration were investigated. Both types of protein at high concentrations (10 and 20 mg L(-1)) suppressed the bioaccumulation of PFASs. When protein concentration increased from 0 to 20 mg L(-1), the decreasing ratios of the PFAS body burden (35.3-52.9%) in Daphnia magna induced by bovine albumin were significantly higher than those (22.0-36.6%) by soy peptone. The dialysis bag experiment results showed that the binding of PFASs to protein followed the Freundlich isotherm, suggesting it is not a linear partitioning process but an adsorption-like process. The partition coefficients of PFASs between bovine albumin and water were higher compared to soy peptone; this resulted in higher reducing rates of freely dissolved concentrations of PFASs with increasing bovine albumin concentration, leading to a stronger suppression of PFAS bioaccumulation. However, the presence of both types of protein with a low concentration (1 mg L(-1)) enhanced the bioaccumulation of PFASs. Furthermore, the water-based bioaccumulation factor based on the freely dissolved concentrations of PFASs even increased with and the depuration rate constants of PFASs from Daphnia magna decreased with protein concentration, suggesting that protein would not only reduce the bioavailable concentrations and uptake rates of PFASs but also lower the elimination rates of PFASs in Daphnia magna. Because these two opposite effects would change with different protein concentrations in water, the net effect of protein on PFAS bioaccumulation would also vary with protein concentration.

Recent developments in methods for analysis of perfluorinated persistent pollutants

Perfluoroalkyl substances (PFASs) are proliferated into the environment on a global scale and present in the organisms of animals and humans even in remote locations. Persistent organic pollutants of that kind therefore have stimulated substantial improvement in analytical methods. The aim of this review is to present recent achievements in PFASs determination in various matrices with different methods and its comparison to measurements of Total Organic Fluorine (TOF). Analytical methods used for PFASs determinations are dominated by chromatography, mostly in combination with mass spectrometric detection. However, HPLC may be also hyphenated with conductivity or fluorimetric detection, and gas chromatography may be combined with flame ionization or electron capture detection. The presence of a large number of PFASs species in environmental and biological samples necessitates parallel attempts to develop a total PFASs index that reflects the total content of PFASs in various matrices. Increasing attention is currently paid to the determination of branched isomers of PFASs, and their determination in food.

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Quantitative determination of perfluorochemicals and fluorotelomer alcohols in plants from biosolid-amended fields using LC/MS/MS and GC/MS

Analytical methods for determining perfluorochemicals (PFCs) and fluorotelomer alcohols (FTOHs) in plants using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) were developed, and applied to quantify a suite of analytes in plants from biosolid-amended fields. Dichloromethane-methanol and ethylacetate were chosen as extracting solutions for PFCs and FTOHs, respectively. Nine perfluorocarboxylic acids (PFCAs), three perfluorosulfonic acids (PFSAs), and ten FTOHs were monitored. Most PFCAs and perfluorooctanesulfonate (PFOS) were quantifiable in plants grown in contaminated soils, whereas PFCs went undetected in plants from two background fields. Perfluorooctanoic acid (PFOA) was a major homologue (∼10-200 ng/g dry wt), followed by perfluorodecanoic acid (∼3-170 ng/g). [PFOS] in plants (1-20 ng/g) generally was less than or equal to most [PFCAs]. The site-specific grass/soil accumulation factor (GSAF = [PFC](Grass)/[PFC](Soil)) was calculated to assess transfer potentials from soils. Perfluorohexanoic acid had the highest GSAF (= 3.8), but the GSAF decreased considerably with increasing PFCA chain length. Log-transformed GSAF was significantly correlated with the PFCA carbon-length (p < 0.05). Of the measured alcohols, 8:2nFTOH was the dominant species (≤1.5 ng/g), but generally was present at ≥10× lower concentrations than PFOA.

Per- and polyfluorinated compounds in house dust and indoor air from northern Norway - a pilot study

Polyfluorinated compounds (PFCs) are an extremely versatile class of compounds and are used in a variety of consumer applications and products. Recent studies have suggested that PFCs in indoor air and dust could act as sources of human exposure and outdoor air contamination. This study presents method development and analysis of a wide range of PFCs in dust and air using active sampling techniques with commercially available sampling equipment (forensic nozzles with filter housings for dust collection and polyurethane foam (PUF)-XAD(2)-PUF sandwich-tubes for air sampling) using both liquid and gas chromatography mass spectrometry. The developed method was validated and tested for applicability to analyze dust and air samples at both low and high concentrations (0.5 ng and 25 ng per analyte per air sample, respectively). Samples from private households and an office building were analyzed to explore differences in distribution patterns and concentrations. Perfluorooctane sulfonate, perfluorodecane sulfonate, perfluoroheptanoate, perfluorooctanoate and perfluorononanoate were observed in all samples of dust from private households, in the range from 1 to 80.1 ng g(-1). Fluorotelomer alcohols (FTOHs) were the predominant PFCs in indoor air samples with ∑FTOHs ranging between 4.7 and 17.9 ng m(-3). The concentrations found in the present study are generally lower than those previously reported. This variation may be due to differences associated with geographical locations and lifestyles. However, use of different sampling techniques and strategies among studies can introduce large variations in PFC concentration found, making direct comparisons challenging.

Halogenated persistent organic pollutants and polycyclic aromatic hydrocarbons in food

During recent years, mass spectrometry (MS) and hyphenated chromatographic instrumentation and techniques have been a subject of dramatic developments, resulting in the introduction of various useful tools for the analysis of halogenated persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in food and environmental matrices. This chapter describes state-of-the-art in the field of MS as a primary detection tool for the halogenated POPs and PAHs previously separated using either gas chromatography (GC) or liquid chromatography (LC). Since sample preparation practice plays a crucial role for obtaining optimal performance characteristics of a particular analytical method, a brief overview of sample extraction and clean-up procedures in the POPs/PAHs analysis is also briefly outlined.

Concentrations, distribution, and persistence of fluorotelomer alcohols in sludge-applied soils near Decatur, Alabama, USA

Soil samples were collected for fluorotelomer alcohol (FTOH) analyses from six fields to which sludge had been applied and one "background" field that had not received sludge. Ten analytes in soil extracts were quantified using GC/MS. Sludge-applied fields had surface soil FTOH concentrations exceeding levels found in the background field. For 8:2nFTOH, which can degrade to perfluorooctanoic acid, impacted surface-soils ranged from 5 to 73 ng/g dry weight, clearly exceeding the background field in which 8:2nFTOH was not detected. The highest [FTOH] generally was 10:2nFTOH, which had concentrations of <5.6 to 166 ng/g. For the first time, we document the persistence of straight-chained primary FTOHs (n-FTOHs) and branch-chained secondary FTOHs (sec-FTOHs), which are transformation products of n-FTOHs, in field soils for at least five years after sludge application. Ratios of sec-FTOHs to n-FTOHs were highest for 7:2sFTOH/8:2nFTOH (∼50%) and decreased with increasing chain length to a minimum for the longest-chained analytes, 13:2sFTOH/14:2nFTOH (∼10%). Disappearance half-lives for FTOHs, calculated with these data, ranged from 0.85 to 1.8 years. These analytical results show that the practice of sludge application to land is a pathway for the introduction of FTOHs and, accordingly, their transformation products, perfluorocarboxylic acids, into the environment.

Analysis of polyfluorinated compounds in foods

Polyfluorinated compounds (PFCs) are a relatively new and diverse set of compounds analyzed as contaminants in food. Their unique physical-chemical properties dictate the methods used for their analysis. Current analyses of the more volatile PFCs involve gas chromatography-mass spectrometry; liquid chromatography-tandem mass spectrometry is generally used for the less volatile PFCs. Considerations in the analysis of PFCs in foods include contamination from the widespread presence of materials that contain various PFCs, endogenous interfering compounds, and matrix effects. Future opportunities for research on PFCs in food exist, particularly in the areas of biological molecule-PFC interactions and the effects of food processing on these interactions. Future research will be facilitated by the synthesis of a wider variety of analytical standards.

Atmospheric perfluorinated acid precursors: chemistry, occurrence, and impacts

Perfluorocarboxylic acids (PFCAs) can be found from the hydrolysis of perfluoroacyl fluorides and chlorides, which can be produced in three separate ways in the atmosphere. Alternatively, PFCAs can be formed directly in the gas phase through reaction of perfluoroacyl peroxy radicals or perfluorinated aldehyde hydrates. All five mechanisms have been elucidated using smog chamber techniques. Yields of the PFCAs from this process vary from less than 10% to greater than 100%, depending on the mechanism. The formation of perfluorosulfonic acids in the atmosphere can also occur, though the mechanism has not been entirely elucidated. A large number of compounds have been confirmed as perfluorinated acid precursors, including CFC-replacement compounds, anesthetics, fluorotelomer compounds, and perfluorosulfonamides. Levels of some of these compounds have been measured in the atmosphere, but concentration for the majority have yet to be detected. It is clear that atmospheric oxidation of volatile precursors contributes to the overall burden of PFAs, though the extent to which this occurs is compound and environment dependent and is difficult to assess accurately.

Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in Shanghai, China

Perfluorinated acids (PFAs) have been recognized as emerging environmental pollutants because of their widespread occurrences, persistence, and bioaccumulative and toxicological effects. PFAs have been detected in aquatic environment and biota in China, but the occurrences of these chemicals have not been reported in solid matrices in China. In the present study, short- and long-chain PFAs (C2-C14) have been quantitatively determined in solid matrices including sediments, soils and sludge collected in Shanghai, China. The results indicate that sludge contains more PFAs than sediments and soils, and the total PFAs concentrations in sediments, soil and sludge are 62.5-276 ng g(-1), 141-237 ng g(-1) and 413-755 ng g(-1), respectively. In most cases, trifluoroacetic acid was the major PFA and accounted for 22-90% of the total PFAs. Although the levels of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) were not only lower than trifluoroacetic acid, but also lower than some short-chain PFCAs (<C8) in some individual cases, PFOA and PFOS were still the major pollution compounds in most cases and they constituted 2-34% and 1-9% of the total PFAs, respectively. Meanwhile, unlike previous studies, PFOS levels were not always higher than PFOA in solids collected in Shanghai, China. Given that some short-chain PFAs such as trifluoroacetic acid are mildly phytotoxic and their higher levels in solid matrices were collected in Shanghai, China, these chemicals should be included in future environmental monitoring efforts.

Semivolatile fluorinated organic compounds in Asian and western U.S. air masses

Semivolatile fluorinated organic compounds (FOCs) were measured in archived air sample extracts collected from Hedo Station Observatory (HSO) on Okinawa, Japan and Mount Bachelor Observatory (MBO), Oregon U.S. during the springs of 2004 (MBO and HSO) and 2006 (MBO). Fluorotelomer alcohols (FTOHs) were measured in both Asian and western U.S. air masses, though western U.S. air masses had significantly higher concentrations. Concentrations of fluorotelomer olefins in Asian air masses and 8:2 fluorotelomer acrylate in U.S. air masses were reported for the first time. N-ethyl perfluorooctane sulfonamide, N-methyl perfluorooctane sulfonamido ethanol, and N-ethyl perfluorooctane sulfonamido ethanol were also measured in Asian and western U.S. air masses but less frequently than FTOHs. The atmospheric sources and fate of FTOHs were investigated by estimating their atmospheric residence times, calculating FTOH concentration ratios, investigating FTOH correlations with nonfluorinated semivolatile organic compound concentrations, and determining air mass back trajectories. Estimated atmospheric residence times for 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH were 50, 80, and 70 d, respectively, and the average concentration ratio of 6:2 FTOH to 8:2 FTOH to 10:2 FTOH at MBO in 2006 was 1.0 to 5.0 to 2.5. The relative order of these atmospheric residence times may explain the observed enhancement of 8:2 FTOH and 10:2 FTOH (relative to 6:2 FTOH) at MBO compared to North American indoor air (FTOH average ratio of 1.0 to 2.0 to 1.0). FTOH concentrations in western U.S. air masses were positively correlated (p < 0.05) with gas-phase polycyclic aromatic hydrocarbon and polychlorinated biphenyl concentrations and negatively correlated (p < 0.05) with agricultural pesticide concentrations. In comparison to western U.S. air masses, trans-Pacific air masses did not contain elevated concentrations of these compounds, whereas lower boundary layer air masses that passed over urban areas of the western U.S. did. This suggests that semivolatile FOCs are emitted from urban areas in the western U.S.

Development and application of a simplified sampling method for volatile polyfluorinated alkyl substances in indoor and environmental air

A new, fast and simple sampling method using commercially available Isolute ENV+ solid-phase extraction (SPE) cartridges for the enrichment of neutral, volatile polyfluorinated alkyl substances (PFAS) was developed and applied to selected air samples. The SPE cartridges showed good retention capacity for the target analytes, and most of the investigated compounds could be quantified in 20m(3) indoor air. Employing the developed method, it was shown that high levels of selected fluorotelomer alcohols (FTOHs) and N-alkyl fluorooctane sulfonamides/-ethanols (FOSAs/FOSEs) evaporated from a paraglider. Furthermore, the new method was compared to the 'classical' approach using glass-fibre filters (GFFs) and XAD-2 resin sandwiched between polyurethane foam plugs (PUF/XAD/PUF) to investigate environmental air concentrations in metropolitan Hamburg. Due to the high counter pressure of SPE cartridges, only low-volume air sampling was feasible. Therefore, the trace levels of FOSAs/FOSEs occurring in environmental air could only be quantified occasionally in the samples enriched on SPE cartridges. However, quantitative analysis of the higher concentrated 6:2 FTOH, 8:2 FTOH and 10:2 FTOH was possible in all low-volume environmental air samples. Finally, the determination of ionic PFAS, including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), bound to airborne particles in the air samples from Hamburg is described.

Extraction and clean-up strategies for the analysis of poly- and perfluoroalkyl substances in environmental and human matrices

The rapidly expanding field of per- and polyfluorinated alkyl substances (PFASs) research has resulted in a wide range of analytical methodologies to determine the human and environmental exposure to PFASs. This paper reviews the currently applied techniques for sample pre-treatment, extraction and clean-up for the analysis of ionic and non-ionic PFASs in human and environmental matrices. Solid phase extraction (SPE) is the method of choice for liquid samples (e.g. water, blood, serum, plasma), and may be automated in an on-line set-up for (large volume) sample enrichment and sample clean-up. Prior to SPE, sample pre-treatment (filtration or centrifugation for water or protein precipitation for blood) may be required. Liquid-liquid extraction can also be used for liquid samples (and does not require above mentioned sample pretreatment). Solid-liquid extraction is the commonly applied method for solid matrices (biota, sludge, soil, sediment), but automation options are limited due to contamination from polytetrafluorethylene tubings and parts applied in extraction equipment. Air is generally preconcentrated on XAD-resins sandwiched between polyurethane foam plugs. Clean-up of crude extracts is essential for destruction and removal of lipids and other co-extractives that may interfere in the instrumental determination. SPE, (fluorous) silica column chromatography, dispersive graphitized carbon and destructive methods such as sulphuric acid or KOH treatment can be applied for clean-up of extracts. Care should be taken to avoid contamination (e.g. from sample bottles, filters, equipment) and losses of PFASs (e.g. adsorption, volatilization) during sampling, extraction and clean-up. Storage at -20 degrees C is generally appropriate for conservation of samples.

Latitudinal gradient of airborne polyfluorinated alkyl substances in the marine atmosphere between Germany and South Africa (53 degrees N-33 degrees S)

Neutral, volatile polyfluorinated alkyl substances (PFAS) were determined in high-volume air samples collected onboard the German research vessel Polarstern during cruise ANTXXIII-1 between Bremerhaven, Germany (53 degrees N) and Capetown, Republic of South Africa (33 degrees S) in fall 2005. An optimized and validated analytical protocol was used for the determination of several fluorotelomer alcohols (FTOHs) as well as N-alkylated fluorooctane sulfonamides and sulfonamidoethanols (FOSAs/FOSEs). Quantitative analyses were done by gas chromatography-mass spectrometry. This study provides the first concentration data of airborne PFAS from the Southern Hemisphere. Results indicate a strongly decreasing concentration gradient from the European continent toward less industrialized regions. The study confirms that airborne PFAS are mainly restricted to the Northern Hemisphere with a maximum concentration of 190 pg/m3 (8:2 FTOH) in the first sample collected in the channel between the European mainland and the UK. However, south of the equator, trace amounts of several FTOHs and FOSAs with a maximum of 14 pg/m3 (8:2 FTOH) could still be detected. Furthermore, a selection of ionic PFAS including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) were determined in the particulate phase of high-volume air samples by liquid chromatography-mass spectrometry. Levels of ionic PFAS were almost 2 orders of magnitude lower than those of neutral PFAS, with maximum concentrations in the first sample of 2.5 pg/m3 (PFOS) and 2.0 pg/m3 (PFOA).

Mass spectral studies of perfluorooctane sulfonate derivatives separated by high-resolution gas chromatography

The mass spectral characteristics of perfluorooctane sulfonate (PFOS, C(8)F(17)SO(3)-) isomers present in technical PFOS were obtained using high-resolution gas chromatography (HRGC) combined with mass spectrometry (MS). To make PFOS amenable to HRGC separation, a simple derivatization procedure was developed. The method involved the conversion of PFOS into the iso-propyl ester using iso-propanol as the derivatization reagent under acidic conditions. Mass spectra were generated employing electron ionization (EI) and negative chemical ionization (NCI). Interpretation of fragment ions was possible due to the use of deuterium-labeled iso-propanol as derivatization reagent, which induced mass shifts in the electron ionization (EI) and negative chemical ionization (NCI) mass spectra. HRMS allowed the accurate mass measurement of important EI fragments and confirmed the derivatization reaction as well as the proposed fragmentation pathway involving rearrangement. Moreover, the high resolution provided by HRGC enabled the separation of eleven PFOS isomers present in the technical product. This is an improvement over the previously reported high-performance liquid chromatography (HPLC) separation. A complete identification of all isomers was not possible due to lack of pure reference materials. Finally, the developed derivatization procedure was successfully applied to perfluoroalkyl carboxylates (PFCA) and corresponding fragmentation involving rearrangement of the derivatized PFCA was observed. The described qualitative derivatization offers a promising alternative technique for the separation and identification of isomers of perfluoroalkyl sulfonates and carboxylates by HRGC/MS.

Analysis of per- and polyfluorinated alkyl substances in air samples from Northwest Europe

Air samples were collected from 4 field sites in Europe: 2 sites from the UK, Hazelrigg (semi-rural) and Manchester (urban); 1 site from Ireland: Mace Head (rural); and 1 site from Norway: Kjeller (rural). Additionally, air samples were taken from indoor locations in Tromsø, Norway. Air samples were collected using high-volume air samplers employing sampling modules containing glass-fibre filters (GFFs, particle phase), and glass columns with a polyurethane foam (PUF)-XAD-2-PUF sandwich (gaseous phase). Typical outdoor air volumes required for the determination of per- and polyfluorinated alkyl substances (PFAS) ranged from 500-1800 m3. GFFs and PUF-XAD columns were analysed separately to obtain information on phase partitioning. All air samples were analysed for volatile, neutral PFAS, with selected GFF samples halved for analysis of both neutral and airborne particle-bound ionic PFAS. Volatile PFAS were extracted from air samples by cold-column immersion with ethyl acetate, and were analysed by gas chromatography-mass spectrometry in the positive chemical ionisation mode (GC-PCI-MS). Ionic PFAS were extracted from GFFs by sonication in methanol, and were analysed by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) using electrospray ionisation in the negative ion mode (ESI-). Perfluorooctanoate (PFOA) was often the predominant analyte found in the particulate phase at concentrations ranging from 1-818 pg m(-3), and 8:2 fluorotelomer alcohol (FTOH) and 6:2 FTOH were the prevailing analytes found in the gas phase, at 5-243 pg m(-3) and 5-189 pg m(-3), respectively. These three PFAS were ubiquitous in air samples. Many other PFAS, both neutral and ionic, were also present, and levels of individual analytes were in the 1-125 pg m(-3) range. Levels of some PFAS exceeded those of traditional persistent organic pollutants (POPs). In this study, the presence of 12:2 FTOH and fluorotelomer olefins (FTolefins), and ionic PFAS other than perfluorooctane sulfonate (PFOS) and PFOA, are reported in air samples for the first time. Concentrations of neutral PFAS were several orders of magnitude higher in indoor air than outdoor air, making homes a likely important diffuse source of PFAS to the atmosphere. Our repeated findings of non-volatile ionic PFAS in air samples raises the possibility that they might directly undergo significant atmospheric transport on particles away from source regions, and more atmospheric measurements of ionic PFAS are strongly recommended.