To Örebro University

This study examined the environmental behaviour and fate of polyfluoroalkyl compounds (PFCs) found in water, suspended particulate matter (SPM) and sediment. The sampling of the sediment was performed at two stations from Tokyo Bay, Japan, in 2008. In addition, a depth profile of seawater was collected at three water layers from both sampling stations. The ∑PFC concentrations ranged from 16.7 to 42.3 ng L^-1 in the water column, from 6.4 to 15.1 ng g^-1 dry weight (dw) in the SPM fraction and from 0.29 to 0.36 dw in surface sediment. The distribution of PFCs was found to depend on their physicochemical characteristics. While short-chain perfluoroalkyl carboxylic acids (PFCAs) (C < 7) were exclusively detected in the dissolved phase, longer-chain PFCAs (C ≥ 7), perfluoroalkyl sulfonates (PFSAs), ethylperfluorooctane sulfonamidoacetic acid (EtFOSAA), and perfluorooctane sulfonamide (PFOSA) appeared to bind more strongly to particles. Results showed that the sorption of PFCs on SPM increases by 0.52-0.75 log units for each additional CF₂ moiety and that the sorption of PFSAs was 0.71-0.76 log units higher compared to the PFCA analogs. In addition, the sorption of PFCs was influenced by the organic carbon content. These data are essential for modelling the transport and environmental fate of PFCs.

The partitioning behavior of per- and polyfluoroalkyl compounds (PFCs) between pore water and sediment in two sediment cores collected from Tokyo Bay, Japan, was investigated. In addition, the fluxes and temporal trends in one dated sediment core were studied. Short-chain perfluoroalkyl carboxylic acids (PFCAs) (C ≤ 7) were found exclusively in pore water, while long-chain PFCAs (C ≥ 11) were found only in sediment. The perfluoroalkyl sulfonates (PFSAs), n-ethylperfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA), and perfluorooctane sulfonamide (PFOSA) seemed to bind more strongly to sediment than PFCAs. The enrichment of PFCs on sediment increased with increasing organic matter and decreasing pH. The perfluorocarbon chain length and functional group were identified as the dominating parameters that had an influence on the partitioning behavior of the PFCs in sediment. The maximum ΣPFC contamination in sediment was observed in 2001-2002 to be a flux of 197 pg cm^-2 yr^-1. Statistically significant increased concentrations in Tokyo Bay were found for perfluorooctanesulfonate (PFOS) (1956-2008), perfluorononanoic acid (PFNA) (1990-2008), and perfluoroundecanoic acid (PFUnDA) (1990-2008). Concentrations of PFOSA and N-EtFOSAA increased between 1985 and 2001, but after 2001, the concentration decreased significantly, which corresponded with the phase out of perfluorooctyl sulfonyl fluoride-based compounds by the 3M Company in 2000.

Laboratory partitioning experiments were conducted to elucidate the sorption behaviour and partitioning of perfluoroalkyl compounds (PFCs). Three different sediment types were used and separately spiked with perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS) and perfluorooctane sulfonamide (PFOSA) at low environmentally realistic concentrations. PFOA, PFOS and PFOSA were mainly distributed in the dissolved phase at low suspended solid concentrations, indicating their long-range transport potential in the marine environment. In all cases, the equilibrium isotherms were linear and the organic carbon normalised partition coefficients (K _OC) decreased in the following order: PFOSA (log K _OC=4.1±0.35cm ³g ^-1)>PFOS (3.7±0.56cm ³g ^-1)>PFOA (2.4±0.12cm ³g ^-1). The level of organic content had a significant influence on the partitioning. For the sediment with negligible organic content the density of the sediment became the most important factor influencing the partitioning. Ultimately, data on the partitioning of PFCs between aqueous media and suspended solids are essential for modelling their transport and environmental fate.

The presence of unidentified organofluorine compounds (UOF) has been investigated in recent publication, but their environmental occurrence is still poorly understood. Fluorine mass balance analysis was performed on environmental samples from lake Mjøsa and river Alna (surface water (n = 9), sediment (n = 5) and fish liver (n = 4)) and sewage samples from Oslo (n = 5), to reveal to the fraction of UOF. In samples that had extractable organofluorine (EOF) concentrations above the limit of detection (LoD), more than 70% of their EOF could not be accounted for by the 37 PFAS monitored in this study. The surface water samples from lake Mjøsa had EOF concentrations several times higher than what has been reported elsewhere in Nordic nations. The flux of EOF in river Alna and selected sewage pipes revealed that it was 1-2 orders of magnitude higher than the flux of the measured PFAS. The elevated concentrations of EOF in all samples pose a potential health and environmental hazard, as their composition remains mostly unknown.

Recent publications have highlighted the ubiquitous presence of unidentified organofluorine compounds, whose environmental occurrence is poorly understood. In this study, wastewater treatment plant (WWTP) effluent and sludge samples from seven countries were analyzed for extractable organofluorine (EOF) and target PFAS, to evaluate which compounds are released back into the environment. Fluorine mass balance analysis of effluent samples (n = 14) revealed that on average 90% of the EOF could not be explained by the 73 PFAS monitored in this investigation. The levels of EOF in effluent (324–1460 ng of F/L) and sludge (39–210 ng of F/g of dry weight) indicate that a substantial amount of organofluorine compounds is released back into nature. A commonly overlooked PFAS class, ultra-short-chain PFCAs, accounted for 4% of EOF on average, while the remaining 71 compounds explained only a further 6% of EOF on average. The highest number of PFAS was detected in the effluent dissolved phase (37), compared to 29 and 23 PFAS in sludge and effluent particulate phase, respectively. The increased concentrations of EOF in both WWTP effluent and sludge are of concern, as the chemical species contained therein remain largely unknown, and thus, their potential health and environmental risks cannot be assessed.

The ubiquitous occurrence of a few per- and polyfluoroalkyl substances (PFAS) in humans and the environment has been previously reported. However, the number of PFAS humans and the environment are potentially exposed to is much higher, making it difficult to investigate every sample in detail. More importantly, recent studies have shown an increasing fraction of potentially unknown PFAS in human samples. A screening tool for identifying samples of concern that may contain high PFAS levels, to be studied more thoroughly, is needed. This study presents a simplified workflow to detect elevated PFAS levels using extractable organofluorine (EOF) analysis. A fluorine mass balance analysis on samples with high EOF, targeting 63 PFAS, can then confirm the PFAS contamination. Whole blood samples from a cohort of individuals with historical drinking water contamination from firefighting foams (n = 20) in Ronneby (Sweden) and a control group (n = 9) with background exposure were used as a case study. The average EOF concentration in the Ronneby group was 234 ng/mLF (<107-592 ng/mLF) vs 24.8 ng/mLF (17.6-37.8 ng/mL F) in the control group. The large difference (statistically significant, p < 0.05) in the EOF levels between the exposed and control groups would have made it possible to identify samples with high PFAS exposure only using EOF data. This was confirmed by target analysis, which found an average ∑PFAS concentration of 346 ng/mL in the exposed group and 7.9 ng/mL in the control group. The limit of quantification for EOF analysis (up to 107 ng/mLF using 0.5 mL whole blood) did not allow for the detection of PFAS levels in low or sub parts per billion (ng/mL) concentrations, but the results indicate that EOF analysis is a suitable screening method sensitive enough to detect elevated/significant/exposure above background levels by known or unknown PFAS.

Combustion ion chromatography (CIC) has found a role in environmental analytical chemistry for fluorine content analysis. It is used for extractable organofluorine (EOF) analysis to evaluate perfluoroalkyl and polyfluoroalkyl substances (PFASs) and other organofluorine burden. The prevailing assumption has been that all PFASs are incinerated in CIC and matrix components have no impact on this process, but this has not been experimentally evaluated. In this work, the combustion efficiencies of 13 different PFASs were determined (66-110%). A notable difference was observed between calibrating the CIC with inorganic fluorine or organofluorine. Potential interferences from cations and coextracted matrix components from whole blood and surface water samples were evaluated. These observations should be acknowledged when performing EOF analysis using CIC, overlooking either non-100% combustion efficiencies or the differences in calibrating the CIC with inorganic fluorine or organofluorine could lead to underestimating EOF content and through that to misguide policy decisions.

Studies have highlighted the increasing fraction of unidentified organofluorine (UOF) compounds in human blood, whose health effects are not known. In this study, 130 whole blood samples from the Swedish general population were analyzed for extractable organofluorine (EOF) and selected per- and polyfluoroalkyl substances (PFAS). Organofluorine mass balance analysis revealed that 60% (0-99%) of the EOF in female samples could not be explained by the 63 monitored PFAS; in males, 41% (0-93%) of the EOF was of unidentified origin. Significant differences between both age groups and gender were seen, with the highest fraction of UOF in young females (70% UOF, aged 18-44), which is contrary to what has been reported in the literature for commonly monitored compounds (e.g., perfluorooctane sulfonic acid, PFOS). Increasing the number of monitored PFAS did not lead to a large decrease of the UOF fraction; the seven highest PFAS (C8-C11 PFCAs, C6-C8 PFSAs) accounted for 98% of sum 63 PFAS. The high fraction of UOF in human samples is of concern, as the chemical species of these organofluorine compounds remain unknown and thus their potential health risks cannot be assessed.

A method for isomer profiling of perfluorinated compounds (PFCs) in water was developed and applied to quantitatively assess the contributions from electrochemical (ECF) and telomer manufacturing processes around source regions of North America, Asia, and Europe. With the exception of 3 sites in Japan, over 80% of total perfluorooctanoate (PFOA, C₇F₁₅COO ^-) was from ECF, with the balance attributable to strictly linear (presumably telomer) manufacturing source(s). Comparing PFOA isomer profiles in samples from China, with PFOA obtained from a local Chinese manufacturer, indicated <3% difference in overall branched isomer content; thus, exclusive contribution from local ECF production cannot be ruled out. In Tokyo Bay, ECF, linear-telomer, and isopropyl-telomer sources contributed to 33%, 53%, and 14% of total PFOA, respectively. Perfluorooctane sulfonate (PFOS, C ₈F₁₇SO₃^-) isomer profiles were enriched in branched content (i.e., >50% branched) in the Mississippi River but in all other locations were similar or only slightly enriched in branched content relative to historical ECF PFOS. Isomer profiles of other PFCs are also reported. Overall, these data suggest that, with the exception of Tokyo Bay, ECF manufacturing has contributed to the bulk of contamination around these source regions, but other sources are significant, and remote sites should be monitored.

For Canadian Arctic indigenous populations, marine mammal (MM) traditional foods (TFs) represent sources of both important nutrients and hazardous environmental contaminants. Food preparation is known to impact the nutrient and environmental contaminant content of processed items, yet the impacts of preparation on indigenous Arctic MM TFs remain poorly characterized. In order to determine how the various processes involved in preparing beluga blubber TFs affect their levels of nutrients and environmental contaminants, we collected blubber samples from 2 male beluga whales, aged 24 and 37 years, captured during the 2014 summer hunting season in Tuktoyaktuk, Northwest Territories, and processed them according to local TF preparation methods. We measured the levels of select nutrients [selenium (Se), polyunsaturated fatty acids (PUFAs)] and contaminants [organochlorine pesticides, perfluoroalkyl and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers, polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs), mercury (Hg)] in raw and prepared (boiled, roasted, aged) beluga blubber TFs. The impacts of beluga blubber TF preparation methods on nutrient and environmental contaminant levels were inconsistent, as the majority of processes either did not appear to influence concentrations or affected the two belugas differently. However, roasting and ageing beluga blubber consistently impacted certain compounds: roasting blubber increased concentrations of hydrophilic substances (Se and certain PFASs) through solvent depletion and deposited PAHs from cookfire smoke. The solid-liquid phase separation involved in ageing blubber depleted hydrophilic elements (Se, Hg) and some ionogenic PFASs from the lipid-rich liquid oil phase, while PUFA levels appeared to increase, and hydrophobic persistent organic pollutants were retained. Ageing blubber adjacent to in-use smokehouses also resulted in considerable PAH deposition to processed samples. Our findings demonstrated that contaminant concentration differences were greater between the two sets of whale samples, based on age differences, than they were within each set of whale samples, due to variable preparation methods. When considering means to minimize human contaminant exposure while maximizing nutrient intake, consumption of aged liquid from younger male whales would be preferred, based on possible PUFA enhancement and selective depletion of hydrophilic environmental contaminants in this food item.

Per- and polyfluoroalkyl substances (PFASs) are a diverse group of chemicals used in consumer products, which will inevitably end up in waste streams. Landfills are widely recognized secondary point sources of PFASs, but other types of waste management sites have received less attention. Therefore, in a case study presented here we investigated releases of PFASs from temporarily stored waste by determining quantities of 34 PFASs in leachate from a Waste-to-Energy stockpile (45 000 ± 2000 tonnes) during five months in 2019. We also measured extractable organofluorine (EOF) to account for PFASs not included in the target list. The mean total concentration of the 34 PFAS (Σ34PFAS) was 211 ± 31 ng/L, and short-chain (C4–C7) perfluorocarboxylic acids (PFCAs) accounted for 56–60% of the total. Moreover, we found that Σ34PFAS only accounted for 12% ± 4% of EOF detected in the leachate. Our results demonstrate that waste stockpiles are previously unexplored sources of PFASs in the environment, and the dominance of short-chain PFCAs is consistent with observed profiles of contaminants in landfill leachates.

C₁-C₄ perfluoroalkyl acids (PFAAs) are highly persistent chemicals that have been found in the environment. To date, much uncertainty still exists about their sources and fate. The importance of the atmospheric degradation of volatile precursors to C₁-C₄ PFAAs were investigated by studying their distribution and seasonal variation in remote Arctic locations. C₁-C₄ PFAAs were measured in surface snow on the island of Spitsbergen in the Norwegian Arctic during January-August 2019. Trifluoroacetic acid (TFA), perfluoropropanoic acid (PFPrA), perfluorobutanoic acid (PFBA), and trifluoromethane sulfonic acid (TFMS) were detected in most samples, including samples collected at locations presumably receiving PFAA input solely from long-range processes. The flux of TFA, PFPrA, PFBA, and TFMS per precipitation event was in the ranges of 22-1800, 0.79-16, 0.19-170, and 1.5-57 ng/m², respectively. A positive correlation between the flux of TFA, PFPrA, and PFBA with downward short-wave solar radiation was observed. No correlation was observed between the flux of TFMS and solar radiation. These findings suggest that atmospheric transport of volatile precursors and their subsequent degradation plays a major role in the global distribution of C₂-C₄ perfluoroalkyl carboxylic acids and their consequential deposition in Arctic environments. The discovery of TFMS in surface snow at these remote Arctic locations suggests that TFMS is globally distributed. However, the transport mechanism to the Arctic environment remains unknown.

Ultra-short-chain perfluoroalkyl acids have recently gained attention due to increasing environmental concentrations being observed. The most well-known ultra-short-chain perfluoroalkyl acid is trifluoroacetic acid (TFA) which has been studied since the 1990s. Potential sources and the fate of ultra-short-chain perfluoroalkyl acids other than TFA are not well studied and data reporting their environmental occurrence is scarce. The analytical determination of ultra-short-chain perfluoroalkyl acids is challenging due to their high polarity resulting in low retention using reversed-phase liquid chromatography. Furthermore, recent studies have reported varying extraction recoveries in water samples depending on the water matrix and different methods have been suggested to increase the extraction recovery. The present review gives an overview of the currently used analytical methods and summarizes the findings regarding potential analytical challenges. In addition, the current state of knowledge regarding TFA and other ultra-short-chain perfluoroalkyl acids, namely perfluoropropanoic acid, trifluoromethane sulfonic acid, perfluoroethane sulfonic acid, and perfluoropropane sulfonic acid‚ are reviewed. Both known and potential sources as well as environmental concentrations are summarized and discussed together with their fate and the environmental and human implications.

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.

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.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a group of emerging persistent organic pollutants. PFASs in soil can affect water quality when they leach into groundwater, and threaten the ecosystem and human health through trophic transfer and magnification along the terrestrial food chains, which make them one of the hot research topics in environmental chemistry. At present, the content of less than 1% of the total fluorinated compounds in the soil can be accurately determined, and the content is at the ng/g level. The research areas in China are concentrated in the east and the surrounding areas of fluorochemical plants. The main compounds of PFASs in soil are PFOS and PFOA. The physicochemical properties of soil, species of PFASs and human activities are the main factors influencing the occurrence of PFASs in different types of soil. In addition to the direct release and atmospheric transport during the production and use of fluorinated chemicals, PFASs precursor conversion in soil is also an important source of PFASs. Adsorption-desorption is the major process affecting the transport of PFASs in soil. Studies also demonstrate that the transport and accumulation of PFASs in soil are affected by various factors such as the chain-length and functional groups of PFASs, soil physicochemical properties and microorganisms. In consideration of the research status, further development of extraction and analytical methods is needed to cover a wider range of PFASs. Attention can be paid to the changing trend and mechanism of novel PFASs in soil. The bioaccessibility and bioavailability study of PFASs in soil are also needed for ecological and human health risk assessment.

The sorption processes of persistent organic pollutants on microplastics particles are poorly understood. Therefore, the present study investigated the sorption processes of perfluorooctanesulfonate (PFOS) on polyethylene (PE) microplastic particles (MPs) which are representing a prominent environmental pollutant and one of the most abundant microplastic polymers in the aquatic environment, respectively. The focus was set on the investigation of the impact of the particle size on PFOS sorption using four different PE MPs size ranges. The sorption kinetics for 6 months was studied with one selected size range of PE MPs. Besides, the desorption of PFOS from PE MPs under simulated digestive conditions was carried out by using artificial gut fluid mimicking the intestinal juice of fish. The investigation of the size effects of particles over 6 months demonstrated a linear increase of PFOS concentration sorbed onto PE with a decrease of the particle size. Thus, our findings implicate efficient sorption of PFOS onto PE MPs of different sizes. The results showed that PFOS desorbed from the PE MPs into the artificial gut fluid with a rate of 70 to 80%. Besides, a longer exposure of PE MPs to PFOS leads to a higher concentration adsorbed by PE MPs, which may favor the ingestion of higher concentration of PFOS, and thus represents a higher risk to transfer relevant concentrations of PFOS during digestion.

Toxicity of polyethylene (PE) and polyvinyl chloride (PVC) microplastics (MPs), either virgin or spiked with chemicals, was evaluated in two short-lived fish using a freshwater species, zebrafish, and a marine species, marine medaka. Exposures were performed through diet using environmentally relevant concentrations of MPs over 4 months. No modification of classical biomarkers, lipid peroxidation, genotoxicity or F0 behaviour was observed. A significant decrease in growth was reported after at least two months of exposure. This decrease was similar between species, independent from the type of MPs polymer and the presence or not of spiked chemicals, but was much stronger in females. The reproduction was evaluated and it revealed a significant decrease in the reproductive output for both species and in far more serious numbers in medaka. PVC appeared more reprotoxic than PE as were MPs spiked with PFOS and benzophenone-3 compared to MPs spiked with benzo[a]pyrene. Further, PVC-benzophenone-3 produced behavioural disruption in offspring larvae. These results obtained with two species representing different aquatic environments suggest that microplastics exert toxic effects, slightly different according to polymers and the presence or not of sorbed chemicals, which may lead in all cases to serious ecological disruptions.

Hexabromocyclododecane (HBCD) is widely used as a brominated flame retardant, and has been detected in the aquatic environment, wild animals, and humans. However, details of the environmental health risk of HBCD are not well known. In this study, zebrafish embryos were used to assess the developmental toxicity of the chemical. Four-hour post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of HBCD (0, 0.05, 0.1, 0.5, and 1.0 mg L^-1) until 96 h. Exposure to 0.1, 0.5, and 1.0 mg L^-1 HBCD significantly increased the malformation rate and reduced survival in the 0.5 and 1.0 mg L^-1 HBCD exposure groups. Acridine orange (AO) staining showed that HBCD exposure resulted in cell apoptosis. Reactive oxygen species (ROS) was significantly induced at exposures of 0.1, 0.5, and 1.0 mg L^-1 HBCD. To test the apoptotic pathway, several genes related to cell apoptosis, such as p53, Puma, Apaf-1, caspase-9, and caspase-3, were examined using real-time PCR. The expression patterns of these genes were up-regulated to some extent. Two anti-apoptotic genes, Mdm2 (antagonist of p53) and Bcl-2 (inhibitor of Bax), were down-regulated, and the activity of capspase-9 and caspase-3 was significantly increased. The overall results demonstrate that waterborne HBCD is able to produce oxidative stress and induce apoptosis through the involvement of caspases in zebrafish embryos. The results also indicate that zebrafish embryos can serve as a reliable model for the developmental toxicity of HBCD.

Brominated flame retardants (BFRs) and brominated dioxins are emerging persistent organic pollutants that are ubiquitous in the environment and can be accumulated by wildlife and humans. These chemicals can disturb endocrine function. Recent studies have demonstrated that one of the mechanisms of endocrine disruption by chemicals is modulation of steroidogenic gene expression or enzyme activities. In this study, an in vitro assay based on the H295R human adrenocortical carcinoma cell line, which possesses most key genes or enzymes involved in steroidogenesis, was used to examine the effects of five bromophenols, two polybrominated biphenyls (PBBs 77 and 169), 2,3,7,8-tetrabromodibenzo-p-dioxin, and 2,3,7,8-tetrabromodibenzofuran on the expression of 10 key steroidogenic genes. The H295R cells were exposed to various BFR concentrations for 48 h, and the expression of specific genes - cytochrome P450 (CYP11A, CYP11B2, CYP17, CYP19, and CYP21), 3β- hydroxysteroid dehydrogenase (3βHSD2), 17β-hydroxysteroid dehydrogenase (17βHSD1 and 17βHSD4), steroidogenic acute regulatory protein (StAR), and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) - was quantitatively measured using real-time polymerase chain reaction. Cell viability was not affected at the doses tested. Most of the genes were either up- or down-regulated, to some extent, by BFR exposure. Among the genes tested, 3βHSD2 was the most markedly up-regulated, with a range of magnitude from 1.6- to 20-fold. The results demonstrate that bromophenol, bromobiphenyls, and bromodibenzo-p-dioxin/furan are able to modulate steroidogenic gene expression, which may lead to endocrine disruption.

Aqueous film-forming foams (AFFFs) are widely used to extinguish liquid fires due to their film-forming properties. AFFF formulation historically contains per- and polyfluoroalkyl substances (PFASs) that can be very persistent and pose a health risk to biota and humans. Detailed analysis of the chemical composition of AFFFs can provide a better understanding on the potential environmental impact of the ingredients. In this study, a novel workflow combining target analysis, nontarget screening analysis (NTA), total fluorine (TF) analysis, and inorganic fluoride (IF) analysis was applied to disclose the chemical composition of 24 foams intended for liquid fires. Foams marketed as containing PFASs as well as fluorine-free foams were included. By comparing the sum of targeted PFASs and total organofluorine concentrations, a mass balance of known and unknown organofluorine could be calculated. Known organofluorine accounted for <1% in most fluorine-containing AFFFs, and it was confirmed that the foams marketed as fluorine-free did not contain measurable amounts of organofluorine substances. Five fluorinated substances were tentatively identified, and non-fluorinated zwitterionic betaine compounds, which are considered to be replacement substances for PFASs, were tentatively identified in the organofluorine-free foams.

The purpose of this study was to investigate the environmental occurrence of ultra-short chain perfluoroalkyl substances (PFASs) in Swedish water samples. So far established protocols have focused on measuring PFASs with a carbon chain length of four or more carbons. In this study, perfluoroalkyl sulfonates of chain lengths of two, perfluoroethane sulfonate (PFEtS), and three, perfluoropropane sulfonate (PFPrS), carbons have been measured using a newly established instrumental method employing supercritical fluid separation (SFC) coupled to tandem mass spectrometry detection.

A total of 26 samples were analysed, including ground water, surface water, rain water and snow. The sample locations included military and civilian airports, a former hard chromium plating facility, the vicinity of a hazardous waste management facility and background areas (lake surface water, rain and snow). Results show that both PFPrS and PFEtS could be detected in environmental samples using SFC separation coupled to triple quadrupole detection. Out of the 26 samples analysed, the ultra-short-chain PFPrS could be detected and quantified in 22 samples. The concentrations for PFPrS in all the samples ranged between 0.93 ng/l to 39 000 ng/l. The ultra-short-chain PFPEtS could be quantified in all of the 26 samples, with a concentration range between 0.07 and 5 700 ng/l. The highest concentrations represents highly contaminated ground water samples collected from a military airport. In the samples, PFPrS had a relative contribution to total PFAS concentration of 6 and 10 %, indicating the importance of measuring these compounds in environmental samples.

Within the global monitoring plan (GMP) established by article 16 of the Stockholm Convention on Persistent Organic Pollutants, perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS) are recommended for analysis in core matrices to assess occurrence and changes geographically and with time. In 101 samples consisting of 86 national pools and 15 pools from States in Brazil obtained between 2008 and 2019, PFHxS was detected in 17% of the national pools and none in Brazil. PFOA and PFOS had a detection frequency of 100% and 92%, respectively. Other perfluoroalkane substances (PFAS) had either low detection frequencies and median values of zero (carboxylic acids C-4-C-11 ; except PFOA) or could not be quantified in any sample (sulfonic acids, C-4-C-10, and long-chain carboxylic acids, C-12-C-14). Correlation between PFOA and PFOS was moderately (r = 0.58). Whereas median values were almost identical (18.9 pg/g f.w. for PFOS; 18.6 pg/g f.w. for PFOA), PFOS showed larger ranges (< 6.2 pg/g f.w.-212 pg/g f.w.) than PFOA (< 6.2 pg/g f.w.-63.4 pg/g f.w.). It was shown that wealthier countries had higher PFOA concentrations than poorer countries. No difference in concentrations was found for samples collected in countries having or not having ratified the Stockholm Convention amendments to list PFOS or PFOA. The goal to achieve 50% decrease in concentrations within ten years was met by Antigua and Barbuda, Kenya, and Nigeria for PFOS and by Antigua and Barbuda for PFOA. In a few cases, increases were observed; one country for PFOS, four countries for PFOA.

This study performed by Örebro University on behalf of the Swedish Environmental Agency aims at assessing the occurrence and levels of the newly identified side-chain fluorinated polymers from an environmental perspective. The aims of present study are 1) to develop instrumental and extraction methods to measure the active ingredient of two Scotchgard products (two side-chain fluorinated polymers, hereafter referred to as Pre-2002 and Post-2002) in sludge and leachate samples from Swedish wastewater treatment plants and landfills; 2) to evaluate if Pre-2002 and Post-2002 may be responsible for the unidentified organofluorine in the sludge samples from our previous screening study reporting extractable organofluorine (EOF); and 3) to conduct a mass balance analysis on EOF and sum of 93 per- and polyfluoroalkyl substances (PFAS) including Pre-2002 and Post-2002 in the sludge and landfill leachate samples to assess the levels of unidentified EOF that potentially are other polymeric or non-polymeric PFAS.

Levels of Pre-2002 and Post-2002 and EOF are reported for sludge samples from four wastewater treatment plants (Bergkvara in Torsås, Gässlösa in Borås, Henriksdal in Stockholm, and Öhn in Umeå) collected in 2015, and leachate samples from three different landfills (Atleverket in Örebro, Hässleholm Kretsloppscenter in Hässleholm, and Flishult in Vetlanda). Sludge samples from Gässlösa wastewater treatment plant collected between 2004 and 2016 (excluding 2005 and 2006) were analyzed to assess any temporal trends of the two side-chain fluorinated polymers (Pre-2002 and Post-2002). The present investigation reported levels of both Pre-2002 and Post-2002 in all sludge samples (158-2618 ng/g d.w.). Levels of Pre-2002 were always higher than those of Post-2002 in the same samples. A declining trend was observed for Pre-2002 in sludge samples from Gässlösa but no clear trend was noted for Post-2002. The concentrations of the Pre-2002 and Post-2002 in sludge were higher than the sum of 83 PFAS analyzed in the previous screening study. No relationship between number of people that the wastewater treatment plants served and the concentrations of EOF and Pre-2002 and Post-2002 could be observed. The concentrations of both EOF and Pre-2002 and Post-2002 seem to be more related to the types of industry located in that area. Only three of the five leachate samples showed detectable levels of Pre-2002. Post-2002 was not detected in any of the landfill leachates. The low levels could be due to that both compounds are strongly sorbed to particles, which indicates the fate and distribution of these compounds. For both the sludge and leachate samples, the quantified levels of Pre-2002 and Post-2002 only contributed to a minor part of the EOF. A high proportion of unknown EOF still remains and may be related to other polymeric or non-polar PFAS.

Thousands of per- and polyfluoroalkyl substances (PFAS) are on the global market, while only a minor proportion is monitored regularly in the environment. Wastewater treatment plants (WWTPs) have been suggested to be a point source for PFAS to the environment due to emission of effluent and sludge. In this study, 81 PFAS including two rarely studied perfluoroalkyl sulfonamide-based (FASA) copolymers were analyzed in sludge samples to understand the usage of PFAS in the society. Sludge samples (n = 28) were collected at four WWTPs in Sweden between 2004 and 2017. The total levels of 79 measured PFAS were between 50 and 1124 ng/g d.w. All sludge samples showed detectable levels of both C8- and C4-FASA-based copolymers. The concentrations of the FASA-based copolymers were proposed to be reported in fluorinated side-chain equivalents (FSC eq.), in order to compare the levels of the copolymers with the other neutral and anionic PFAS, as no authentic standards were available. The concentrations of the FASA-based copolymers in sludge were between 1.4 and 22 ng FSC eq./g d.w. A general predomination of precursor and intermediate compounds was observed. A lower contribution of perfluoroalkyl carboxylic acids was noted for the WWTPs more influenced by domestic emission when compared with more influenced by industrial emission. An overall declining trend in the total PFAS concentration was seen between the years 2004 and 2017. The present study observed a shift from the C8-based chemistry toward shorter chain lengths, included a declining trend for C8-FASA-based copolymer over the entire study period. These findings further demonstrate the occurrence of side-chain fluorinated copolymers in Sweden and that sludge is a useful matrix to reflect the usage of PFAS in society and the potential for environmental exposure.

Side-chain fluorinated polymers are speculated to be potential precursors to other non-polymeric aliphatic per- and polyfluoroalkyl acids (PFAAs). Limited knowledge of environmental occurrence of this compound class is partly due to lack of structural information and authentic standards. In this study, two novel fluorinated compounds, suspected to be side-chain fluorinated copolymers used in two commercial technical mixtures (Scotchgard™ Pre-2002 formulation and Scotchgard™ Post-2002 formulation) were analyzed and characterized in order to provide information to facilitate detection and quantification. The commercial mixtures were analyzed using tandem mass spectrometry and high-resolution mass spectrometry; besides already reported C4- and C8-fluoroalkylsulfonamido (FASA) side-chains, a proposed structure was determined for the perfluorooctane (C8) sulfonamide-urethane copolymer in the Pre-2002 formulation. Structural isomers were also observed for C4- and C8-FASA-based copolymers. Total fluorine analysis revealed that the Scotchgard™ Pre-2002 Formulation contained a fluorine content of 0.5% and 1.8% for the Scotchgard™ Post-2002 Formulation. The equivalent FASA side-chain content was determined to be 0.8% for Pre-2002 and 3.1% for Post-2002. Both C4- and C8-FASA-based copolymers underwent hydrolysis and oxidation and were transformed to their respective perfluoroalkyl side chain, which suggest that transformation products can be analyzed for example after total oxidizable precursor (TOP) assay. Both compounds were shown to strongly sorb to sediment particles, which also gives indications about their environmental fate and transport pathways.

Concentrations of nine antibiotics [erythromycin-H₂O (ERY-H₂O); trimethoprim (TMP); tetracycline (TET); norfloxacin (NOR); penicillin G (PEN G); penicillin V (PEN V); cefalexin (CLX); cefotaxim (CTX); and cefazolin (CFZ)] were measured in influent and effluent samples from four sewage treatment plants (STPs) in Hong Kong as well as in influent samples from one STP in Shenzhen. Levels of PEN V and CFZ were below method detection limits in all of the samples analyzed. CLX concentrations were the highest in most of the Hong Kong samples, ranging from 670 to 2900 ng/L and 240 to 1800 ng/L in influent and effluent samples, respectively, but CLX was not detected in the samples from Shenzhen. Comparatively lower concentrations were observed for ERY-H₂O (470-810 ng/L) and TET (96-1300 ng/L) in the influent samples from all STPs in Hong Kong. CTX was found to be the dominant antibiotic in the Shenzhen STP influents with a mean concentration of 1100 ng/L, but occurred at lower concentrations in Hong Kong sewage. These results likely reflect regional variations in the prescription and use patterns of antibiotics between Hong Kong and Shenzhen. Antibiotic removal efficiencies depended on their chemical properties and the wastewater treatment processes used. In general, relatively higher removal efficiencies were observed for NOR (5-78%) and TET (7-73%), which are readily adsorbed to particulate matter, while lower removal efficiencies were observed for ERY-H₂O (9-19%), which is relatively persistent in the environment. Antibiotics were removed more efficiently at Hong Kong STPs employing secondary treatment processes compared with those using primary treatment only. Concentrations of NOR measured in effluents from STPs in Hong Kong were lower than the predicted no-effect concentration of 8000 ng/L determined in a previous study. Therefore, concentrations of antibiotics measured in this preliminary study would be unlikely to cause adverse effects on microorganisms used in wastewater treatment processes at the sampled STPs.

Perfluorooctanoic acid (PFOA; Pentadecafluorooctanoic acid) is widely used in various industrial applications. It is persistent in the environment and does not appear to undergo further degradation or transformation. PFOA is found in tissues including blood of wildlife and humans; however, the environmental fate and biological effects of PFOA remain unclear. Microarray techniques of gene expression have become a powerful approach for exploring the biological effects of chemicals. Here, the Affymetrix, Inc. rat genome 230 2.0 GeneChip was used to identify alterations in gene regulation in Sprague-Dawley rats treated with five different concentrations of PFOA. Male rats were exposed by daily gavage to 1, 3, 5, 10, or 15 mg PFOA/kg, body weight (bw)/day for 21 days and at the end of the exposure, liver was isolated and total liver RNA were used for the gene chip analysis. Over 500 genes, whose expression was significantly (p < 0.0025) altered by PFOA at two-fold changes compared to control, were examined. The effects were dose-dependent with exposure to 10 mg PFOA/kg, bw/day, causing alteration in expression of the greatest number of genes (over 800). Approximately 106 genes and 38 genes were consistently up- or down-regulated, respectively, in all treatment groups. The largest categories of induced genes were those involved in transport and metabolism of lipids, particularly fatty acids. Other induced genes were involved in cell communication, adhesion, growth, apoptosis, hormone regulatory pathways, proteolysis and peptidolysis and signal transduction. The genes expression of which was suppressed were related to transport of lipids, inflammation and immunity, and especially cell adhesion. Several other genes involved in apoptosis; regulation of hormones; metabolism; and G-protein coupled receptor protein signaling pathways were significantly suppressed.

Recent studies showed that perfluorooctane sulfonate (PFOS) affects the mammalian immune system at levels reportedly found in the general human population. It has been demonstrated that exposure to immunotoxic chemicals may diminish the host resistance of animals to various pathogenic challenges and enhance mortality. Therefore, the current study was carried out to characterize the effect of a 21 day pre-administration of zero, 5, or 25 μg PFOS/kg bw/day in female B6C3F1 mice on host resistance to influenza A virus infection. At the end of PFOS exposure, body/organ weights did not significantly change whereas PFOS distribution in blood plasma, spleen, thymus and lung was dose-dependently increased. PFOS exposure in mice resulted a significant increase in emaciation and mortality in response to influenza A virus. The effective plasma concentrations in female mice were at least several fold lower than reported mean blood PFOS levels from occupationally exposed humans, and fell in the upper range of blood concentrations of PFOS in the normal human population and in a wide range of wild animals. Hence, it should be important to clarify the precise mechanism(s) for excess mortality observed in the high dose group.

A wide range of fluorinated alkyl compounds (FACs) has been reported in wildlife in various locations in the world. However, such information regarding Japanese wildlife is rarely found. In the present study, we investigated the occurrence of 21 FACs, including perfluorinated alkyl sulfonates (PFASs), perfluorinated carboxylates (PFCAs), and fluorotelomer acids, in the livers of 10 wild bird species from two regions in northern Japan. To avoid interferences, FACs were quantified by a recently developed method using acetonitrile and solid-phase extraction followed by an ion exchange HPLC column separation. Apart from perfluorooctane sulfonate (PFOS), which was found at the highest levels of all the compounds detected, several long chain perfluorinated carboxylates (PFCAs) from C8 to C16, particularly perfluorotetradecanoic acid (PFTeDA) and perfluorohexadecanoic acid (PFHxDA), were detected for the first time. Additionally, 7:3 FTCA, a fluorotelomer acid, was also detected in most swan livers from Miyagi prefecture and all the birds from Tochigi prefecture. However, none of the sulfonamides and unsaturated telomer acids were detected in any species. Swans seem to be the least exposed wild birds to FACs among the investigated birds, signifying that feeding habits may reflect FAC accumulation in wild birds. The highest total concentration of detected FACs was 405ngg^-1wet wt., which was found in a Japanese sparrowhawk, indicating that the top predatory wild birds can accumulate several long chain carboxylic acids. However, the current FAC concentrations found in livers may suggest that these compounds alone would not cause a severe toxic effect in these species.

Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; the lungs, liver, and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a C_max at 3 h post exposure. The C_max following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in the plasma, liver, and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to 65-71% and 74-87% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicates that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that can have accumulated in rats.

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.

With the current possible presence of thousands of PFAS compounds in industrial emissions, there is an increasing need to assess the impacts of PFAS regulation of conventional PFAS on one hand and the exposure to emerging and yet unknown PFAS on the other. Today's analytical methodologies using targeted approaches are not sufficient to determine the complete suite of PFAS present. To evaluate the presence of unknown PFAS, we investigated in this study the occurrence of an extended range of target PFAS in various species from the marine and terrestrial Norwegian environment, in relation to the extractable organofluorine (EOF), which yields the total amount of organofluorine. The results showed a varying presence of extractable fluorinated organics, with glaucous gull eggs, otter liver and polar bear plasma showing the highest EOF and a high abundance of PFAS as well. The targeted PFAS measurements explained 1% of the organofluorine for moose liver as the lowest and 94% for otter liver as the highest. PFCAs like trifluoroacetic acid (TFA, reported semi-quantitatively), played a major role in explaining the organic fluorine present. Emerging PFAS as the perfluoroethylcyclohexane sulfonate (PFECHS), was found in polar bear plasma in quantifiable amounts for the first time, confirming earlier detection in arctic species far removed from emission sources. To enable a complete organic fluorine mass balance in wildlife, new approaches are needed, to uncover the presence of new emerging PFAS as cyclic- or ether PFAS together with chlorinated PFAS as well as fluorinated organic pesticides and pharmaceuticals.

BACKGROUND: Between 2013 and 2015, concentrations of poly- and perfluoroalkyl substances (PFAS) in public drinking water supplies serving at least six million individuals exceeded the level set forth in the health advisory established by the U.S. Environmental Protection Agency. Other than data reported for contaminated sites, no systematic or prospective data exist on the relative source contribution (RSC) of drinking water to human PFAS exposures.

OBJECTIVES: This study estimates the RSC of tap water to overall PFAS exposure among members of the general U.S.

POPULATION:

METHODS: We measured concentrations of 15 PFAS in home tap water samples collected in 1989-1990 from 225 participants in a nationwide prospective cohort of U.S. women: the Nurses' Health Study (NHS). We used a one-compartment toxicokinetic model to estimate plasma concentrations corresponding to tap water intake of PFAS. We compared modeled results with measured plasma PFAS concentrations among a subset of 110 NHS participants.

RESULTS: Tap water perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) were statistically significant predictors of plasma concentrations among individuals who consumed [Formula: see text] cups of tap water per day. Modeled median contributions of tap water to measured plasma concentrations were: PFOA 12% (95% probability interval 11%-14%), PFNA 13% (8.7%-21%), linear perfluorooctanesulfonic acid (nPFOS) 2.2% (2.0%-2.5%), branched perfluorooctanesulfonic acid (brPFOS) 3.0% (2.5%-3.2%), and perfluorohexanesulfonic acid (PFHxS) 34% (29%-39%). In five locations, comparisons of PFASs in community tap water collected in the period 2013-2016 with samples from 1989-1990 indicated increases in quantifiable PFAS and extractable organic fluorine (a proxy for unquantified PFAS).

CONCLUSIONS: Our results for 1989-1990 compare well with the default RSC of 20% used in risk assessments for legacy PFAS by many agencies. Future evaluation of drinking water exposures should incorporate emerging PFAS.

The risks to Indo-Pacific Humpback Dolphins and Finless Porpoises associated with polychlorinated biphenyls (PCBs) were assessed. Stomach contents from twelve stranded Humpback Dolphins and sixteen stranded Finless Porpoises were collected. Concentrations of total and isomer-specific PCBs in the stomach contents were determined using dual-column gas chromatography equipped with electron capture detectors (GC-ECD). Risks due to the PCBs were assessed in three scenarios, based on total PCBs (summation of 41 PCB congeners), total toxicity equivalency (TEQs) and PCB 118, using the toxicity reference values (TRVs) as the threshold effects benchmarks. The calculated risk quotients (RQs) showed that risks due to PCBs were generally low or negligible. Specifically, RQs from total TEQs and total PCBs for Finless Porpoises are below one, suggesting that PCBs should be a low risk for the Finless Porpoise in Hong Kong waters. However, the Humpback Dolphin has RQs larger than 1 for total TEQs and total PCBs when the 95th percentile data were used in the evaluation. This indicates that further investigation may be needed to examine more closely the potential impact of toxic contaminants in the habitat of the Humpback Dolphin.

The ubiquitous occurrence of per- and polyfluoroalkyl substances (PFAS) and the detection of unexplained extractable organofluorine (EOF) in drinking water have raised growing concerns. A recent study reported the detection of inorganic fluorinated anions in German river systems, and therefore, in some samples, EOF may include some inorganic fluorinated anions. Thus, it might be more appropriate to use the term "extractable fluorine (EF) analysis" instead of the term EOF analysis. In this study, tap water samples (n = 39) from Shanghai were collected to assess the levels of EF/EOF, 35 target PFAS, two inorganic fluorinated anions (tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-)), and novel PFAS through suspect screening and potential oxidizable precursors through oxidative conversion. The results showed that ultra-short PFAS were the largest contributors to target PFAS, accounting for up to 97% of ΣPFAS. To the best of our knowledge, this was the first time that bis(trifluoromethanesulfonyl)imide (NTf2) was reported in drinking water from China, and p-perfluorous nonenoxybenzenesulfonate (OBS) was also identified through suspect screening. Small amounts of precursors that can be oxidatively converted to PFCAs were noted after oxidative conversion. EF mass balance analysis revealed that target PFAS could only explain less than 36% of EF. However, the amounts of unexplained extractable fluorine were greatly reduced when BF4- and PF6- were included. These compounds further explained more than 44% of the EF, indicating the role of inorganic fluorinated anions in the mass balance analysis.

Per- and polyfluoroalkyl substances (PFAS) have raised concerns due to their worldwide occurrence and adverse effects on both the environment and humans as well as posing challenges for monitoring. Further collection of information is required for a better understanding of their occurrence and the unknown fractions of the extractable organofluorine (EOF) not explained by commonly monitored target PFAS. In this study, eight pairs of raw and treated water were collected from drinking water treatment plants (DWTPs) around Taihu Lake in China and analyzed for EOF and 34 target PFAS. Mass balance analysis of organofluorine revealed that at least 68% of EOF could not be explained by target PFAS. Relatively higher total target concentrations were observed in 4 DWTPs (D1 to D4) when compared to other samples with the highest sum concentration up to 189 ng L^-1. PFOA, PFOS and PFHxS were the abundant compounds. Suspect screening analysis identified 10 emerging PFAS (e.g., H-PFAAs, H-PFESAs and OBS) in addition to target PFAS in raw or treated water. The ratios PFBA/PFOA and PFBS/PFOS between previous and current studies showed significant replacements of short-chain to long-chain PFAS. The ratios of the measured PFAS concentrations to the guideline values showed that some of the treated drinking water exceeds guideline values, appealing for efforts on drinking water safety guarantee.

Surface sediments from remote lakes and coastal areas from Ny-Ålesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Ålesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Ålesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.

BACKGROUND: Perfluoroalkyl phosphinic acids (PFPiAs) have been detected in humans, wildlife, and various environmental matrices. These compounds have been used with perfluoroalkyl phosphonic acids (PFPAs) as surfactants in consumer products and as nonfoaming additives in pesticide formulations. Unlike the structurally related perfluoroalkyl sulfonic and carboxylic acids, little is known about the biological fate of PFPiAs.

OBJECTIVES: We determined the biotransformation products of PFPiAs and some pharmacokinetic parameters in a rat model.

METHODS: Male Sprague-Dawley rats received an oral gavage dose of either C6/C8PFPiA, C8/C8PFPiA, or C8PFPA. Blood was sampled over time, and livers were harvested upon sacrifice. Analytes were quantified using ultra-high-performance liquid chromatography-tandem mass spectrometry or gas chromatography-mass spectrometry.

RESULTS: PFPiAs were metabolized to the corresponding PFPAs and 1H-perfluoroalkanes (1H-PFAs), with 70% and 75% biotransformation 2 wk after a single bolus dose for C6/C8PFPiA and C8/C8PFPiA, respectively. This is the first reported cleavage of a C-P bond in mammals, and the first attempt, with a single-dose exposure, to characterize the degradation of any perfluoroalkyl acid. Elimination half-lives were 1.9±0.5 and 2.8±0.8 days for C6/C8PFPiA and C8/C8PFPiA, respectively, and 0.95±0.17 days for C8PFPA. Although elimination half-lives were not determined for 1H-PFAs, concentrations were higher than the corresponding PFPAs 48 h after rats were dosed with PFPiAs, suggestive of slower elimination.

CONCLUSIONS: PFPiAs were metabolized in Sprague-Dawley rats to form persistent PFPAs as well as 1H-PFAs, which contain a labile hydrogen that may undergo further metabolism. These results in rats produced preliminary findings of the pharmacokinetics and metabolism of PFPiAs, which should be further investigated in humans. If there is a parallel between the disposition of these chemicals in humans and rats, then humans with detectable amounts of PFPiAs in their blood may be undergoing continuous exposure.

Since the detection of per- and polyfluoroalkyl substances (PFAS) in humans and different environmental media in the last two decades, this substance group has attracted a lot of attention as well as increasing concerns. The fluorine mass balance approach, by comparing the levels of targeted PFAS after conversion to fluorine equivalents with those of extractable organic fluorine (EOF), showed the presence of unidentified organofluorine in different environmental samples. Out of the thousands of PFAS in existence, only a very small fraction is included in routine analysis. In recent years, liquid chromatography coupled with tandem-mass spectrometry (LC-MS/MS) has demonstrated the ability to analytically cover a wide spectrum of PFAS. In contrast, conventional extraction methods developed 10 to 15 years ago were only evaluated for a limited number of PFAS. The aim of the present study was to evaluate the advantages and disadvantages of three different extraction methods, adapted from the literatures without further optimization (ion-pair liquid-liquid extraction, solid-phase extraction (SPE), using hydrophilic-lipophilic (HLB) or weak anion exchange (WAX) sorbents), for human biomonitoring of 61 PFAS in serum and placental tissue samples. In addition, levels of EOF were compared among these extraction methods via spiked samples. Results showed that performance, in terms of recovery, differed between the extraction methods for different PFAS; different extraction methods resulted in different EOF concentrations indicating that the choice of extraction method is important for target PFAS and EOF analysis. Results of maternal serum samples, analyzed in two different laboratories using two different extraction methods, showed an accordance of 107.6% (± 21.3); the detected perfluoroalkyl acids (PFAAs) in maternal and cord serum samples were in the range of 0.076 to 2.9 ng/mL.Graphical abstract.

Embryos and fetuses are of major concern due to their high vulnerability. Previous studies demonstrated that human exposure to per- and polyfluoroalkyl substances (PFAS) may be underestimated because only a limited number of known PFAS can be measured. This investigation studied the total PFAS exposure by measuring the extractable organofluorine (EOF) in pooled maternal serum, placental tissue, and cord serum samples (total number of pooled samples: n = 45). The EOF was analyzed using combustion ion chromatography, and the concentrations of known PFAS were determined using ultraperformance liquid chromatography coupled with a tandem mass spectrometer. Using a mass balance analysis approach, the amount of unknown PFAS was estimated between the levels of known PFAS and EOF. The EOF levels ranged from 2.85 to 7.17 ng F/mL (21 PFAS were quantified) in the maternal serum, from 1.02 to 1.85 ng F/g (23 PFAS were quantified) in the placental tissue, and from 1.2 to 2.10 ng F/mL (18 PFAS were quantified) in the cord serum. An average of 24, 51, and 9% of EOF is unidentified in the maternal serum, placental tissue, and cord serum, respectively. The results show that the levels of unidentified EOF are higher in the placental tissue, suggesting accumulation or potential transformation of precursors in the placenta.