Mass Balance of Perfluoroalkyl Acids, Including Trifluoroacetic Acid, in a Freshwater Lake.

Perfluoroalkyl acids (PFAAs) are highly persistent chemicals that are ubiquitously found in the environment. The atmospheric degradation of precursor compounds has been identified as a source of PFAAs and might be an important pathway for contamination. Lake Vättern is one of Sweden's largest lakes and is an important source for drinking water. In addition to contamination via atmospheric deposition, the lake is subject to several potential contamination sources via surface water inflow. The relevance of different sources is not well understood. A mass balance of selected PFAAs was assembled based on measured concentrations in atmospheric deposition, surface water from streams that constitute the main inflow and outflow, and surface water in the lake. The largest input was seen for trifluoroacetic acid (150 kg/year), perfluoropropanoic acid (1.6 kg/year), perfluorobutanoic acid (4.0 kg/year), and perfluoro-octanoic acid (1.5 kg/year). Both atmospheric deposition and surface water inflow was found to be important input pathways. There was a positive correlation between the input of most perfluoroalkyl carboxylic acids via atmospheric deposition and global radiation and between the input via surface water inflow and catchment area. These findings highlight the importance of atmospheric oxidation of volatile precursor compounds for contamination in surface waters.

Analysis of hexafluoropropylene oxide-dimer acid (HFPO-DA) by Liquid Chromatography-Mass Spectrometry (LC-MS): Review of Current Approaches and Environmental Levels.

Emerging per- and polyfluorinated compounds (PFAS) compounds are of increasing interest for environmental monitoring, one being hexafluoropropylene oxide-dimer acid (HFPO-DA), commonly referred to as GenX. The following review describes existing liquid chromatography-mass spectrometry (LC-MS) methods used to analyze HFPO-DA, including sample preparation and method sensitivity relative to other PFAS. Analytical challenges are also described, in particular the significant formation of in-source fragmentation, dimer and dimer adducts which detract from [M-H]- signal. Lastly, detected levels of HFPO-DA in environmental and biological samples are compared across the limited number of available field exposure studies, which found several µg/L concentrations in water samples taken near fluorochemical plant discharges.

Ultra-Short-Chain Perfluoroalkyl Acids Including Trifluoromethane Sulfonic Acid in Water Connected to Known and Suspected Point Sources in Sweden.

Data presenting the environmental occurrence of ultra-short-chain perfluoroalkyl acids (PFAAs) are scarce and little is known about the potential sources. In this study, ultra-short-chain PFAAs were analyzed in water connected to potential point sources using supercritical fluid chromatography coupled with tandem mass spectrometry. Samples (n = 34) were collected in connection with firefighting training sites, landfills, and a hazardous waste management facility. Ultra-short-chain PFAAs were detected in all samples at concentrations up to 84 000 ng/L (∑C1-C3), representing up to 69% of the concentration of 29 per- and polyfluoroalkyl substances (PFASs). Trifluoroacetic acid (TFA), perfluoropropanoic acid (PFPrA), trifluoromethane sulfonic acid (TFMS), perfluoroethane sulfonic acid (PFEtS), and perfluoropropane sulfonic acid (PFPrS) were detected at concentrations up to 14 000, 53 000, 940, 1700, and 15 000 ng/L, respectively. Principal component analysis suggests that TFA is associated with landfills. PFPrS was associated with samples collected close to the source at all types of sites included in this study. These findings reveal the presence of high concentrations of ultra-short-chain PFAAs released into the environment from various sources and emphasize the large fraction of ultra-short-chain PFAAs to the total concentration of PFASs in water.

Levels and distribution profiles of Per- and Polyfluoroalkyl Substances (PFAS) in a high Arctic Svalbard ice core.

Per- and polyfluoroalkyl substances (PFAS) are a group of persistent organic contaminants of which some are toxic and bioaccumulative. Several PFAS can be formed from the atmospheric degradation of precursors such as fluorotelomer alcohols (FTOHs) as well as hydrochlorofluorocarbons (HFCs) and other ozone-depleting chlorofluorocarbon (CFC) replacement compounds. Svalbard ice cores have been shown to provide a valuable record of long-range atmospheric transport of contaminants to the Arctic. This study uses a 12.3 m ice core from the remote Lomonosovfonna ice cap on Svalbard to understand the atmospheric deposition of PFAS in the Arctic. A total of 45 PFAS were targeted, of which 26 were detected, using supercritical fluid chromatography (SFC) tandem mass spectrometry (MS/MS) and ultra-performance liquid chromatography (UPLC) MS/MS. C2 to C11 perfluoroalkyl carboxylic acids (PFCAs) were detected continuously in the ice core and their fluxes ranged from 2.5 to 8200 ng m-2 yr-1 (9.51-16,500 pg L-1). Trifluoroacetic acid (TFA) represented 71 % of the total mass of C2 - C11 PFCAs in the ice core and had increasing temporal trends in deposition. The distribution profile of PFCAs suggested that FTOHs were likely the atmospheric precursor to C8 - C11 PFCAs, whereas C2 - C6 PFCAs had alternative sources, such as HFCs and other CFC replacement compounds. Perfluorooctanesulfonic acid (PFOS) was also widely detected in 82 % of ice core subsections, and its isomer profile (81 % linear) indicated an electrochemical fluorination manufacturing source. Comparisons of PFAS concentrations with a marine aerosol proxy showed that marine aerosols were insignificant for the deposition of PFAS on Lomonosovfonna. Comparisons with a melt proxy showed that TFA and PFOS were mobile during meltwater percolation. This indicates that seasonal snowmelt and runoff from post-industrial accumulation on glaciers could be a significant seasonal source of PFAS to ecosystems in Arctic fjords.

Liquid chromatography-ion mobility-high resolution mass spectrometry for analysis of pollutants in indoor dust: Identification and predictive capabilities.

Dust analysis provides a means to assess the degree of exposure of humans in an indoor environment to various contaminant classes such as flame retardants, pesticides and others. There is increasing interest in non-targeted acquisitions using high resolution mass spectrometry (HRMS) to better capture the contaminant profile. However, these studies are confronted with the challenge of assessing confidence in proposed identifications, particularly when authentic standards are not available. Here, we demonstrate the analysis of dust extracts representing various indoor environments (industrial e-waste processing and domestic) for high-abundance environmental contaminants using a data-independent LC-HRMS approach, incorporating ion mobility spectrometry (IMS) to provide additional characterization capability for the complex samples. Twenty-nine xenobiotic compound identifications were made based on both targeted and non-targeted processing approaches using accurate mass precursor and product ion measurement combined with an ion mobility derived collision-cross section (TWCCSN2) determination. Characterization of the repeatability of TWCCSN2 value measurements and their average relative error to compared authentic standards of 0.38% were consistent with various published studies and represent a robust measurement property. TWCCSN2 values were particularly useful in cases where confirmation after the initial dust analysis was performed using a different chromatographic method, due to the gas-phase measurement being unaffected by such changes. Observed compound TWCCSN2 values were then compared to predicted CCSN2 values obtained using two different machine-learning based predictive techniques. Results from one of the predictive programs indicates a promising avenue for use of these models for supporting compound identification in non-targeted analyses.

Analysis of brominated flame retardants and their derivatives by atmospheric pressure chemical ionization using gas chromatography coupled to tandem quadrupole mass spectrometry.

A validated method using an atmospheric pressure chemical ionization source for coupling gas chromatography (GC-APCI) to tandem quadrupole mass spectrometry (MS/MS) for the determination of brominated flame retardants (BFRs) is presented. Polybrominated diphenyl ethers (PBDEs), their methoxylated derivatives (MeO-PBDEs) and other emerging BFRs were included in this study. The method showed good linearity and repeatability. The relative standard deviation (RSD) of the relative response factors (RRFs) of all compounds was below 16%. Repeatability for BFRs was tested on one or two concentration levels of calibration standards with RSDs for RRFs below 16%. The lowest calibration standards (0.075-0.1pg/µL for emerging BFRs, BDE 209 and MeO-PBDEs mixtures, 0.625-6.25pg/µL for Br1-9 PBDEs mixtures) were used as instrument detection limits (IDL). The method was applied on biotic samples, including fish, osprey, and seal. In general, BDE 209 and decabromodiphenyl ethane (DBDPE) were detected in 50% of the seal samples. A 100% detection rate was achieved for 6-MeO-BDE 47 in all the samples (72-580pg/g ww in osprey samples, 24,000-96,000pg/g ww in seal samples and 78-99pg/g ww in fish samples). All Br3-6 PBDEs (BDE 28, 47, 99, 100, 153, 154) were detected in all the samples (ranging from 12 to 20,000pg/g ww), while BDE 183 was detected in 60% of the osprey eggs, 20% of the seal samples and below MDL in all fish samples. The results presented indicate the capability of the GC-APCI-MS/MS system for the detection and quantification of BFRs.

Gas chromatography/atmospheric pressure chemical ionization/mass spectrometry for the analysis of organochlorine pesticides and polychlorinated biphenyls in human serum.

A method using a novel atmospheric pressure chemical ionization source for coupling gas chromatography (GC/APCI) to triple quadrupole mass spectrometry (MS/MS) for the determination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) regulated by the Stockholm Convention is presented. One microliter injection of a six-point calibration curve of native PCBs and OCPs, ranging from 0.04 to 300pg/µL, was performed. The relative standard deviation (RSD) of the relative response factors (RRFs) was less than 15% with a coefficient of determination (r(2))>0.995. Meanwhile, two calibration solutions (CS), CS 2 (0.4pg/µL) and CS 3 (4pg/µL) were analyzed to study the repeatability calculated for both area and RRFs. The RSD for RRF ranged from 3.1 to 16% and 3.6 to 5.5% for CS 2 and CS 3, respectively. The limits of detection (LOD) determined by peak-to-peak signal-to-noise ratio (S/N) of 3 were compared between the GC/APCI/MS/MS and a GC coupled to high resolution mass spectrometry (GC/HRMS) system. GC/APCI/MS/MS resulted in lower LOD for most of the compounds, except for PCB#74, cis-chlordane and trans-chlordane. GC/APCI/MS/MS and GC/HRMS were also compared by performing analysis on 75 human serum samples together with eight QA/QC serum samples. The comparison between GC/APCI/MS/MS system and GC/HRMS system for 16 of the targeted compounds was carried out. No statistically significant difference was discovered. Due to increased sensitivity and user friendly operation under atmospheric pressure, GC/APCI/MS/MS is a powerful alternative technique that can easily meet the specification of GC/HRMS.

Human dietary exposure to perfluoroalkyl substances in Catalonia, Spain. Temporal trend.

In this study, we assessed the levels of 18 perfluoroalkyl substances (PFASs) in the most widely consumed foodstuffs in Catalonia, Spain, as well as the total dietary intake of these compounds. Forty food items were analysed. Only perfluoropentanoic acid (PFPeA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctanoicdecanoic acid (PFOcDA) were not detected in any sample. Perfluorooctane sulfonate (PFOS) was the compound found in the highest number of samples (33 out of 80), followed by perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA) and perfluorodecane sulfonic acid (PFDS). Fish and shellfish was the food group in which more PFASs were detected and where the highest PFAS concentrations were found. The highest dietary intakes corresponded to children, followed by male seniors, with values of 1787 and 1466ng/day, respectively. For any of the age/gender groups of the population, the Tolerable Daily Intakes (TDIs) recommended by the EFSA were not exceeded. In general terms, PFAS levels found in the current study are lower than the concentrations recently reported in other countries.

Levels in food and beverages and daily intake of perfluorinated compounds in Norway.

Perfluorinated compounds (PFCs) have been determined in 21 samples of selected food and beverages such as meat, fish, bread, vegetables, milk, drinking water and tea from the Norwegian marked. Up to 12 different PFCs were detected in the samples. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were found in concentrations similar to or lower than what has been observed in other studies world-wide. Differences in the relative proportion of PFOA and PFOS between samples of animal origin and samples of non-animal origin were observed and support findings that PFOS has a higher bioaccumulation potential in animals than PFOA. Based on these 21 measurements and consumption data for the general Norwegian population, a rough estimate of the total dietary intake of PFCs was found to be around 100 ng d(-1). PFOA and PFOS contributed to about 50% of the total intake. When dividing the population in gender and age groups, estimated intakes were decreasing with increasing age and were higher in males than females. The estimated intakes of PFOS and PFOA in the present study are lower than what has been reported in studies from Spain, Germany, United Kingdom, Canada and Japan. This study illustrates that by improving the analytical methods for determination of PFC in food samples, a broad range of compounds can be detected, which is important when assessing dietary exposure.

Exposure to perfluorinated compounds in Catalonia, Spain, through consumption of various raw and cooked foodstuffs, including packaged food.

In this study, the role that some food processing and packaging might play as a source of perfluorinated compounds (PFCs) through the diet was assessed. The levels of PFCs were determined in composite samples of veal steak (raw, grilled, and fried), pork loin (raw, grilled, and fried), chicken breast (raw, grilled, and fried), black pudding (uncooked), liver lamb (raw), marinated salmon (home-made and packaged), lettuce (fresh and packaged), pate of pork liver, foie gras of duck, frankfurt, sausages, chicken nuggets (fried), and common salt. Among the 11 PFCs analyzed, only PFHxS, PFOS, PFHxA, and PFOA were detected in at least one composite sample, while the levels of the remaining PFCs (PFBuS, PFHpA, PFNA, PFDA, PFUnDA, and PFDoDA) were under their respective detection limits. PFOS was the compound most frequently detected, being found in 8 of the 20 food items analyzed, while PFHxA was detected in samples of raw veal, chicken nuggets, frankfurt, sausages, and packaged lettuce. According to the results of the present study, it is not sufficiently clear if cooking with non-stick cookware, or packaging some foods, could contribute to a higher human exposure to PFCs.