ArticleLiterature Review

Perfluorochemical surfactants in the environment

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Abstract

Concern is growing about fluorinated organic compounds, which are globally distributed, environmentally persistent, bioaccumulative, and potentially harmful. Little is known about how fully fluorinated compounds are transported in air, and methods are needed for understanding their movement into remote regions, say John Giesy and Kurunthachalam Kannan. They discuss current knowledge about these compounds and future research needs.

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... Per and polyfluoroalkyl substances, denoted by the acronym PFASs, refer to a group of man-made emerging contaminants that have been produced since the early 1950s (Giesy & Kannan, 2002). They are aliphatic substances, containing one or more carbon atoms, with hydrogen atoms on their alkyl chain being replaced by fluorine atoms (Buck et al., 2011). ...
... Although sources of PFASs are anthropogenic, their distribution in the environment is ubiquitous. Numerous studies have detected concentrations even in pristine ecosystems and remote areas such as the arctic (Giesy & Kannan, 2002;Kwok et al., 2013;Åkerblom et al., 2017). This phenomenon is due to long-range transportation and deposition of the substances, which commonly happens by means of oceanic currents and sea spray, or atmospheric degradation of precursors . ...
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Per- and polyfluoroalkyl substances (PFASs) are a group of anthropogenic aliphatic compounds, widelyknown for their environmental persistence and toxicity to living beings. While they are ubiquitous in theenvironment, interest has been focused on contaminated soil, which can act as a primary recipient andsource of groundwater contamination. Electrokinetic technology is based on the movement of ionsunder the effect of an electric field. This could be a promising remediation solution, since PFASs areusually present in their anionic form. The contaminants can then be concentrated towards the anode,thus reducing a plume’s volume and possibly extracting the substances from soil. The preliminary aimof the present study was to evaluate the potential of using electrodialysis for the remediation of PFAScontaminatedsoil for the first time. Experiments were run with natural contaminated soil samples,originating from a fire-fighting training site at Arlanda Airport, and at Kallinge, Sweden, as well as inartificially spikedsoil. Electrodes were placed in electrolyte-filled chambers and separated by the soilwith ion-exchange membranes for pH-control. In total, five experiments were conducted. Two differentsetups were tested, a typical 3-compartment EKR cell and a 2-compartment setup, to allow for pHincrease and facilitate PFAS desorption. Two different current densities were tested; 0.19 mA cm-2 and0.38 mA cm-2. After twenty-one days, soil was cut in ten parts lengthwise and triplicate samples wereanalysed for PFAS concentrations, with HPLC-MS/MS. Sixteen out of the twenty-six screened PFASswere detected above MDL in the natural soil samples. The majority of the detected PFASs showed apositive trend of electromigration towards the anode, under both current densities, with only longerchainedcompounds (c>8) being immobile. This can be attributed to the stronger sorption potential oflong-chained PFAS molecules, as has been reported in previous sorption studies. Mass balancedistribution for a high current density (0.38 mA cm-2) experiment revealed that 73.2% of Σ26PFAS wasconcentrated towards the anode, with 59% at the soil closer to the anode, 5.7% at the anion exchangemembrane and 8.5% at the anolyte. It also showed higher mobility for short-chained molecules (c≤6),as they were the only compounds to be extracted from soil and be concentrated in the anolyte. Highercurrent densities were not directly correlated with higher electromigration rates, as to the lack of massbalance data for the low current density experiments. Regardless, electrodialysis could be a viable optionfor PFAS soil remediation and further research to encourage the understanding of the migrationmechanism, as well as combination with other treatment methods is encouraged.
... Per-and polyfluorinated alkyl substances (PFAS) present an ongoing concern for environmental and human health (US-EPA, 2021b) and PFAS are a diverse group of >10,776 substances that have multiple carbon-fluorine (Williams et al., 2017). These chemicals have unique characteristics that make them sought after in the production of numerous industrial, commercial, and consumer products, and with their continued production since the 1940s (Banks et al., 2013;Buck et al., 2011), these compounds can be found world-wide in all environmental niches (Giesy and Kannan, 2002). ...
... The perfluoro-alkyl acids predominate, in part, due to their large historical usage relative to the other PFAS but also due to breakdown/biotransformation of the other PFAS to carboxylic and sulfonyl acids as the end products (Tal and Vogs, 2021;Zhang et al., 2022). PFAS are known be persistent, bioaccumulative and toxic to humans and wildlife, and exposures to PFAS chemicals comes through various media including food, water, air, soil, and sediment (DeWitt, 2015;Brooke et al., 2004;Buck et al., 2011;Suja et al., 2009;Giesy and Kannan, 2002). For the carboxylic acids, bioaccumulation with aquatic species increases with increasing aliphatic chain length for seven carbon and longer carboxylic acids, and for the sulfonic acids, bioaccumulation increases up to aliphatic chain length of eight carbons and then plateaus with increasing chain length (Burkhard 2021). ...
Article
Per- and polyfluoroalkyl substances (PFAS) are widely used across the globe in commercial products such textiles, firefighting foams, and surface coatings. Some PFAS, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are known to be bioaccumulative. Numerous terrestrial ecosystems including sites near PFAS manufacturing facilities, facilities using PFAS in their manufacturing processes, firefighting training areas, landfills, and agricultural fields treated with some pesticide formulations, have been contaminated with PFAS. Earthworms reside at the base of the terrestrial food chain and to perform risk assessments at terrestrial sites contaminated with PFAS, information on the bioaccumulation of PFAS is needed. To understand the bioaccumulation of PFAS by earthworms, a literature search was performed, and biota-soil accumulation factors (BSAFs), measured in laboratory tests and at field sites contaminated with PFAS, were assembled and evaluated in this review. Based on this review, we conclude that there is enough data available for carboxylic and sulfonic acid PFAS classes to derive useful BSAFs for terrestrial risk assessments. Laboratory tests with PFOS and PFOA will be close to or at steady-state conditions with standardized testing protocols, and for the longer chain carboxylic and sulfonic acids, it is unlikely they will reach steady-state with the completion of the uptake exposure. For PFAS classes beyond the carboxylic and sulfonic acids, data are limited and performing terrestrial risk assessments with these PFAS will be difficult. Lastly, additional measurements are needed for non-acid PFAS classes as well as from field settings for all PFAS classes. Across all studies, PFOS and PFOA had average (±standard deviation, counts) BSAFs (kg-OC/kg-ww) of 0.167 (±0.311, n=60) and 0.0413 (±0.175, n=47), respectively.
... PFAS are of interest because most have long persistence in the environment and widespread presence in humans and wildlife (Evich et al., 2022;Wang et al., 2017;Bach et al., 2017;Buck et al., 2011;D'Agostino et al., 2017;Houde et al., 2006;Armitage et al., 2009;Schultz et al., 2004;Giesy et al., 2002). PFAS have been used in many products since the 1950s, including food packaging, nonstick cooking pans, electronics, carpets, fabrics, paints, adhesives, personal care products, and firefighting foams (Richardson and Ternes, 2022). ...
... Notably, eicosane, a structurally long-chain alkane (C19-C25) that serves as a primary component in surfactants, was hardly removed. The eicosane and the aforementioned long-chain fatty acids were found to be extensively applied in personal care products (e.g., soap and shampoo) and industrial materials (e.g., textile and papermaking) (Giesy and Kannan, 2002). ...
... Since the 1940s, these compounds have been used in many industrial applications and commercial products due to their exceptional water-, oil-and stain-repellent properties (Kissa, 2001). The widespread and intensive usage of PFAS combined with their highly persistent, bioaccumulative and mobile properties have resulted in global contamination of virtually every environmental compartment and organism on earth (Cousins et al., 2020;Giesy and Kannan, 2002). ...
... It is recognised globally that per-and poly-fluoroalkyl substances (PFASs) will be a generational chemical of concern to human health and ecosystems [1, 2•, 3]. The high persistence and mobility of a large number of PFAS [4•, 5-7] has resulted in their widespread distribution and accumulation in the environment [8][9][10] and concern regarding potential human and environmental health effects [11][12][13][14][15][16][17][18][19]. ...
Article
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Purpose of Review The unique properties of per- and polyfluoroalkyl substances (PFASs) have seen their widespread adoption, subsequent accumulation in the environment and concern regarding potential environmental effects. Globally, airfields and paved firefighting training surfaces are hotspots for accumulation of PFAS due to extensive use of aqueous film-forming foams (AFFF). Evidence from contaminated concrete and asphalt airfield and training pavements suggests they may serve as an enduring PFAS source. This review investigates sealants as remediation technologies to minimise PFAS mobilisation from pavements drawing on current knowledge of remediation options for soils, sediments, surface and groundwaters. Recent Findings The review did not identify any published sealant information specific to PFAS. Our analysis showed that surface and penetrative sealants may offer an immediate solution via encapsulation of PFAS residues in concrete and asphalt. The most promising surface sealants likely to minimise water ingress and PFAS leaching are selected polymers and (modified) bitumen, owing to the relatively low cost, good adhesion, trafficability and chemical, heat and UV resistance. Potential also exists to enhance PFAS immobilisation using additives to absorb or otherwise chemically bind PFAS. Prospective penetrative sealants include silicates or siloxanes that bind to internal mineral surfaces and/or fill pores to restrict PFAS mobility. It is likely that combinations of surface and penetrative sealants will be required to meet functional, operational and management requirements with respect to new or existing contamination in concrete or asphalt pavements. Summary At present, few if any sealants have been evaluated for their ability to bind or mitigate PFAS mobility. This review serves as a starting point for further studies to evaluate their short or long-term effectiveness in immobilisation of PFAS residues in in situ or ex situ concrete and asphalt. Several knowledge gaps along with suggestions for future research have been made.
... 1 Due to their longlasting stability 2 and potential hazard for ecological health, 3−5 PFC removal has been proposed and has gained increasing attention. 6,7 Recently, the US EPA updated the health advisory levels of PFOA and PFOS in drinking water as 0.004 and 0.02 ng L −1 , respectively, while the Chinese government set new standards for PFOS and PFOA at 40 and 80 ng L −1 , respectively. ...
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Perfluorochemicals (PFCs), especially perfluorooctanoic acid (PFOA), have contaminated the ground and surface waters throughout the world. Efficient removal of PFCs from contaminated waters has been a major challenge. This study developed a novel UV-based reaction system to achieve fast PFOA adsorption and decomposition without addition of sacrificial chemicals by using synthetic photocatalyst sphalerite (ZnS-[N]) with sufficient surface amination and defects. The obtained ZnS-[N] has the capability of both reduction and oxidation due to the suitable band gap and photo-generated hole-trapping properties created by surface defects. The cooperated organic amine functional groups on the surface of ZnS-[N] play a crucial role in the selective adsorption of PFOA, which guarantee the efficient destruction of PFOA subsequently, and 1 μg L-1 PFOA could be degraded to <70 ng L-1 after 3 h in the presence of 0.75 g L-1 ZnS-[N] under 500 W UV irradiation. In this process, the photogenerated electrons (reduction) and holes (oxidation) on the ZnS-[N] surface work in a synergistic manner to achieve complete defluorination of PFOA. This study not only provides promising green technology for PFC-pollution remediation but also highlights the significance of developing a target system capable of both reduction and oxidation for PFC degradation.
... Perfluoroalkyl substances (PFASs) have unique physical properties, and therefore have wide applications both in industry and daily life [1][2][3][4][5], however there are several disadvantages to these compounds. The increase in production and application of PFASs inevitably leads to their release into the environment, where they tend to persist due to limited photolysis, hydrolysis, and biodegradation [6], causing them to accumulate in organisms [7]. ...
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Fluorine industry parks (FIPs) play a fundamental role in the advancement of China’s fluorine industry. In this study, Target analysis was combined with traceability analysis to determine the type of PFASs present in the surface water and sediment around FIPs in China. Meanwhile, the risk they posed to the surrounding river was examined through risk characterisation ratio. Among the areas surveyed, 10 and 15 PFASs were detected in the surface water and sediment, with concentrations of up to 32,674.0 ng/L and 17.84 ng/g, respectively. There were a larger proportion of short-chain PFASs (C4-C7), and perfluoropentanoic acid was particularly prevalent. Source analysis indicates that the PFASs in the surface water may have originated from precursor degradation and atmospheric deposition. The fluorine rubber industry was the main source for the sediment PFASs, particularly for short-chain compounds. A risk characterisation ratio analysis identified perfluorododecanoic acid, perfluorobutane sulfonate, perfluoroheptanoic acid, perfluoropentanoic acid, and perfluorohexanoic acid as compounds with relatively high risks.
... PFAS are of interest because most have long persistence in the environment and widespread presence in humans and wildlife (Evich et al., 2022;Wang et al., 2017;Bach et al., 2017;Buck et al., 2011;D'Agostino et al., 2017;Houde et al., 2006;Armitage et al., 2009;Schultz et al., 2004;Giesy et al., 2002). PFAS have been used in many products since the 1950s, including food packaging, nonstick cooking pans, electronics, carpets, fabrics, paints, adhesives, personal care products, and firefighting foams (Richardson and Ternes, 2022). ...
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Per- and polyfluoroalkyl substances (PFAS) are high-profile environmental contaminants, many having long persistence in the environment and widespread presence in humans and wildlife. Following phase-out of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in North America and restrictions in Europe, PFAS replacements are now widely found in the environment. While liquid chromatography (LC)-mass spectrometry (MS) is typically used for measurement, much of the PFAS is missed. To more comprehensively capture organic fluorine, we developed sensitive and robust methods using activated carbon adsorption, solid phase extraction, and combustion ion chromatography (CIC) to measure total organic fluorine (TOF) in industrial wastewaters, river water, and air. Two extraction techniques, adsorbable organic fluorine (AOF) and extractable organic fluorine (EOF), were optimized and compared using 39 different PFAS, including replacements, such as GenX and perfluorobutanesulfonate. Our AOF method achieves 46-112% and 87% recovery for individual PFAS and PFAS mixtures, respectively, with 0.5 µg/L limit of detection (LOD) for a 50 mL sample volume and a 0.3 μg/L LOD for a 500 mL sample volume . Our EOF method achieves 72-99% and 91% recovery for individual PFAS and PFAS mixtures, respectively, with 0.2 µg/L LOD for a 500 mL sample volume and 0.1 μg/L LOD for 1200 mL. In addition to 39 anionic PFAS, two zwitterionic PFAS and two neutral PFAS were evaluated using the optimized TOF methods. Substantially higher TOF values were measured in industrial wastewater, river water, and air samples compared to LC-MS/MS, demonstrating how TOF methods provided a more comprehensive measurement of the total PFAS present, capturing known and unknown organic fluorine.
... Fluorine is the most electronegative element, and bound fluorine is one of the most stable elements. Fluorine attracts electrons to itself by chemical bonds, giving polarity and strength to the C-F bond (~110 kcal/mol) [1]. The high-energy C-F bond makes PFCs resistant to hydrolysis, photolysis, and biodegradation, and makes them persist in the environment. ...
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Perfluorosulfonic acids (PFSAs) are a recalcitrant subclass of per- and polyfluoroalkyl substances (PFASs) linked to numerous negative health effects in humans. Scalable technologies that effectively destroy PFSAs will greatly reduce the future health and ecological impact of these "forever chemicals". Herein, we show that several PFSAs undergo facile mechanochemical destruction (MCD) in the presence of quartz sand (SiO2). This process operates in the absence of solvent, at ambient temperature and pressure, generating a benign solid byproduct. Quantitative analysis of milled samples revealed high destruction efficiencies of 99.95% to 100% for five different PFSAs subjected to MCD conditions in the presence of SiO2 only. Extensive nontargeted analysis showed that, during degradation, other PFASs form and are ultimately destroyed upon extended mechanochemical treatment. Direct polarization (DP) and cross-polarization (CP) solid-state nuclear magnetic resonance (SSNMR) spectroscopy showed abundant silicon-fluorine (Si-F) bond formation post-MCD, indicating that fluorine was secured in a stable reservoir. Collectively, these results identified the degradation profile for an environmentally sound and effective PFSA degradation process that is amenable to scale-up.
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As regulations are being established to limit the levels of per- and polyfluoroalkyl substances (PFAS) in drinking water and wastewater, effective treatment technologies are needed to remove or destroy PFAS in contaminated liquid matrices. Many military installations and airports have fire training ponds (FTPs) where PFAS-containing firefighting foams are discharged during training drills. FTP water disposal is expensive and challenging due to the high PFAS levels. Hydrothermal alkaline treatment (HALT) has previously been shown to destroy a wide range of PFAS compounds with a high degree of destruction and defluorination. In this study, we investigate the performance of a continuous flow HALT reactor for destroying PFAS in contaminated FTP water samples. Processing with 5 M-NaOH and 1.6 min of continuous processing results in >99% total PFAS destruction, and 10 min processing time yields >99% destruction of every measured PFAS species. Operating with 0.1 M-NaOH or 1 M-NaOH shows little effect on the destruction of measured perfluorosulfonic acids, while all measured perfluorocarboxylic acids and fluorotelomer sulfonates are reduced to levels below the method detection limits. Continuous HALT processing with sufficient NaOH loading appears to destroy parent PFAS compounds significantly faster than batch HALT processing, a positive indicator for scaling up HALT technology for practical applications in environmental site remediation activities.
Article
Legacy and emerging per- and polyfluoroalkyl substances (PFAS) have attracted growing attention due to their potential adverse effects on humans. We developed a method to simultaneously determine thirty-three PFAS (legacy PFAS, precursors, and alternatives) in human plasma and serum using solid phase extraction coupled to ultra-performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS). The method yielded good linearity (>0.995) and excellent limits of detection (LODs) (0.0005~0.012 ng mL-1 in plasma and 0.002~0.016 ng mL-1 in serum). The relative recoveries ranged from 80.1 to 116%, with intra- and inter-day precision less than 14.3%. The robustness of this method has been tested continuously for 10 months (coefficients of variation <14.9%). Our method was successfully applied to the PFAS analysis of 42 real human plasma and serum samples collected from women. The proposed method is attractive for the biomonitoring of multi-class PFAS in human health risk assessment and epidemiological studies.
Article
Perfluorobutane sulfonate (PFBS) has oily and hydrophobic characteristics similar to those of perfluorooctane sulfonic acid (PFOS), which is an environmental organic pollutant and has gradually become the main substitute for PFOS in industry. Several studies have revealed the potential toxicity of PFBS in animals. PFBS can be taken up and accumulate in plants; however, whether and how PFBS affects plant growth remain largely unclear. A low concentration of PFBS did not affect plant growth, indicating that it had higher environmental safety than other perfluorinated compounds; however, a high concentration of PFBS (> 1 mM) markedly inhibited primary root growth in Arabidopsis thaliana. Subsequently, we investigated the molecular mechanisms underlying plant growth mediated by high concentrations of PFBS. First, a genome-wide transcriptomic analysis revealed that PFBS altered the expression of genes associated with phytohormone signaling pathways. Combining physio-biochemical and genetic analyses, we next demonstrated that PFBS reduced the contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and disrupted the two signaling pathways in plants, finally inhibiting root growth. Moreover, a high concentration of PFBS also inhibited photosynthesis by comprehensively repressing the expression of genes related to the Calvin cycle and the photosynthetic apparatus. Such an understanding is helpful for elucidating the phytotoxicity of PFBS and provides a new strategy for toxicology research on organic pollutants in plants.
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The incidence of Leydig cell adenomas increases in CD rats fed for 2 years with the hepatic peroxisome proliferator, ammonium perfluorooctanoate (C8). Treatment with C8 increased the serum concentration of estradiol in 2-week gavage studies, and feeding studies at various time points up to 2 years, and was also accompanied by increases in liver weight and hepatic beta-oxidation activity. Since peroxisome proliferators induce both hepatic beta-oxidation and specific cytochrome P450 enzymes, C8 may also induce aromatase (cytochrome P450-19A1), the cytochrome P450 monooxygenase which converts androgens to estrogens. This hypothesis was investigated in the present study. Adult male CD rats were dosed daily by gavage for 14 days with 0, 0.2, 2, 20, or 40 mg C8/kg body wt. An additional group, the pair-fed control, was fed at a rate matched to the daily consumption by the 40 mg C8/kg group. Treatment with C8 produced a dose dependent decrease in body weight, and increases in absolute and relative liver weights, and in the protein yield of hepatic microsomes. These C8-induced changes were associated with a 2-fold increase in the serum concentration of estradiol and up to a 16-fold increase in total hepatic aromatase activity. A significant linear correlation was established between serum estradiol and total hepatic aromatase activity. The absolute weights and the aromatase activity of the testes were not affected by C8. Hepatic peroxisomal beta-oxidation activity and the microsomal concentration of total cytochrome P450 were also increased by C8. A comparison of estimated EC50 values suggested that these parameters may be less sensitive to induction by C8 than hepatic aromatase activity. Co-incubation of control liver microsomes with C8 in the aromatase assay for 2 hr dose dependently reduced the apparent aromatase activity. This inhibition of aromatase in vitro but increase in vivo was further investigated using cultured rat hepatocytes. Decreases in aromatase activity were found after up to 42 hr of treatment with C8, but the enzyme activity was increased almost 2-fold after 66 hr. The results of this study suggest that the increased serum concentration of estradiol produced by C8 in rats is at least partly due to a direct effect on the liver to increase synthesis of estradiol through induction of aromatase cytochrome P450 in the endoplasmic reticulum.
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Sodium dichloroacetate (DCA) is a drug with potential for treating patients with stroke and head injury. Conflicting evidence has been published on the mutagenic potential of DCA. A series of genetic tests for mutagenicity and clastogenicity was carried out on pharmaceutical grade DCA. Four types of mutagenicity test were included, with and without metabolic activation where appropriate. These studies included: (i) Salmonella and Escherichia coli mutation (Ames) tests, (ii) thymidine kinase locus forward mutation in L5178Y mouse lymphoma cells, (iii) tests for chromosomal aberrations in Chinese hamster ovary cells, and (iv) an in vivo rat bone marrow erythroid micronucleus test. In each study, there was no evidence of mutagenic activity attributable to DCA. It is possible that the present test material, of pharmaceutical grade, has fewer impurities than materials studied in previous reports. These data extend, and in some cases contradict, previous published reports on DCA.
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Organofluorine air contaminants at sub parts per million or higher levels are collected on a solid adsorbent (activated charcoal or graphitized carbon) or in water and then combusted in an oxyhydrogen torch. Combustion converts organic fluorine to hydrogen fluoride, and the fluoride ion is determined with a fluoride ion-selective electrode. The method avoids sample desorption problems and the separation of complex mixtures by commonly used gas chromatographic methods. The maximum concentration each fluoro compound can have in the air sample is calculated from the organofluorine concentration. A specific method may not be needed if the calculated maximum concentration is below an acceptable limit. In conjunction with a specific method, the organofluorine method can detect unidentified fluoro compounds in air not accounted for by the specific method.
Article
The Wickbold oxyhydrogen combustion method is an excellent way of decomposing organic fluorine compounds for determination of fluorine. In this method the vaporized organic fluoride or its partial combustion products are passed through an oxyhydrogen flame which decomposes the sample to carbon dioxide and hydrogen fluoride. The hydrogen fluoride is absorbed in dilute sodium hydroxide solution and subsequently titrated with thorium nitrate. This method is rapid and eliminates the difficulty resulting from high salt content normally present after a Parr bomb-type decomposition.
Article
A gas chromatographic technique utilizing a microwave-sustained helium plasma detector () was developed to study the biotransformation of 1H,1H,2H,2H-perfluorodecanol (C8F17CH2CH2OH) in adult male rats. The metabolic products resulting from a single oral dose of the alcohol were isolated from the blood plasma by an extraction technique, derivatized, and characterized by the system with confirmation by fluorine NMR. Four fluorine-containing metabolites were detected by the fluorine-specific channel of the element-selective MPD and one of these was shown to be perfluorooctanoate (C7F15COO−). Appearance of perfluorooctanoate as a metabolite and an additional observation of concomitant elevation in plasma and urinary inorganic fluoride suggests that the biotransformation of the above alcohol to the perfluorooctanoate involves defluorination of the CF2 group adjacent to the CH2 group in the parent compound.
Article
The cellular effects of sulfluramid (N-ethylperfluorooctane sulphonamide, NEPFOS) and its major metabolite perfluorooctane sulphonamide (PFOS) were examined using a suspension of rabbit renal proximal tubules as a model. NEPFOS and PFOS were potent stimulators of proximal tubule basal oxygen consumption (QO(2)), with initial effects exhibited at 5-10 mum and maximal effects at 50-200 mum. The increase in basal QO(2) was ouabain insensitive, which suggests that NEPFOS and PFOS may act by uncoupling oxidative phosphorylation. Exposure of tubule suspensions to NEPFOS or PFOS concentrations of 100 mum or higher for 60 min produced tubule death, indicated by an increase in the release of lactate dehydrogenase. The tubule death did not appear to result from alkylation or lipid peroxidation, since glutathione and malondialdehyde levels were unaffected. To determine the mechanism by which NEPFOS and PFOS increased tubule QO(2), the effects of NEPFOS and PFOS on isolated renal cortical mitochondria were examined. NEPFOS (10 mum) and PFOS (5 mum) increased state-4 respiration of mitochondria in the absence of a phosphate acceptor. These results suggest that NEPFOS and PFOS uncouple oxidative phosphorylation and may produce cytotoxicity through this mechanism.
Article
Perfluorodecanoic acid (PFDA) is a peroxisome proliferator that causes a dose-dependent (20-80 mg/kg) increase in hepatic triacylglycerol and cholesteryl ester levels in the rat. We hypothesized that PFDA may cause an increase in the de novo synthesis of fatty acids and cholesterol in this species, which would explain observed effects. The incorporation of 3H2O into tissue lipids was examined 7 days after rats received vehicle or 20 or 80 mg/kg of PFDA. PFDA treatment decreased the rate of synthesis of cholesterol and fatty acids in the live and in epididymal fat pad. At a PFDA dose (20 mg/kg) that decreased de novo synthesis of fatty acids and cholesterol, there was no effect on the concentration of fatty acids and cholesterol in the liver, epididymal fat pads, and plasma. We conclude that PFDA induced fatty liver is due to either a decrease in the oxidation of fatty acids in the liver, or an impairment of triacylglycerol catabolism and/or export from the liver, and is not the result of an increase in de novo synthesis of fatty acids and cholesterol.
Article
Tissue distribution, metabolism, and excretion of perfluorodecanoic acid (PFDA) after a single intraperitoneal dose (20 mg/kg) were studied in female and male Wistar rats. PFDA accumulated in the serum and tissues of the rats. In the serum, more than 99% of PFDA was bound by the serum proteins. In the liver, anionic and esterified PFDA were detected. Metabolic oxidation of PFDA was not observed. PFDA was not excreted in urine either by females or males during 14 days after the administration. At the same time, about 0.5% of the administered PFDA dose was excreted daily in the faeces by both sexes. In spite of the analogical structure with perfluorooctanoic acid (PFOA), which is rapidly eliminated in urine by the female rats, PFDA accumulated similarly in females and males. The reduced elimination of PFDA partially explains its greater toxicity to rats in comparison with PFOA.
Article
The effects of sulfluramide (N-ethylperfluorooctane sulfonamide) and perfluorooctane sulfonamide (DESFA) on isolated rabbit renal cortical mitochondria (RCM) were examined. Sulfluramid (1-100 microM) and DESFA (0.5-50 microM) increased state 4 respiration of RCM respiring on pyruvate/malate or succinate in a concentration dependent manner in the absence of a phosphate acceptor. In addition, both sulfluramid and DESFA increased state 4 respiration in the presence of oligomycin, an inhibitor of F0F1-ATPase. The effects of sulfluramid (200 microM), DESFA (100 microM), and the known protonophore and uncoupler of oxidative phosphorylation, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) (1 microM), on RCM proton movement were examined directly by monitoring extramitochondrial pH and indirectly by monitoring passive mitochondrial swelling. Immediately upon addition, DESFA and FCCP, but not sulfluramid, dissipated the RCM proton gradient and caused RCM to swell in solutions of NaCl or NH4Cl. These results show that DESFA uncouples oxidative phosphorylation by acting as a protonophore. RCM were shown to metabolize sulfluramid to DESFA which suggests that the increase in state 4 respiration observed with sulfluramid is due to DESFA. DESFA is unique in that it is one of two uncouplers that does not contain a ring structure and thus may be a useful model in the study of oxidative phosphorylation.
Article
Effects of perfluorodecanoic acid (PFDA, 20-80 mg/kg, ip) on the androgenic status of sexually mature male rats were investigated 7 days after treatment. PFDA decreased plasma androgen concentrations in a dose-dependent fashion with an ED50 of approximately 30 mg/kg. The highest dose of PFDA decreased plasma testosterone and 5 alpha-dihydrotestosterone concentrations to 12 and 18%, respectively, of ad libitum-fed control (ALC) values. Secondary to the decreased plasma androgen concentrations were dose-related decreases in the weights and epithelial heights of accessory sex organs. Results from pair-fed control (PFC) rats show that hypophagia in PFDA-treated rats was not a major cause of the low plasma androgen concentrations. When rats were castrated and implanted with testosterone-containing capsules, PFDA-treated and ALC rats had similar plasma testosterone concentrations and secondary sex organ weights. Therefore, the androgenic deficiency in intact PFDA-treated rats does not result from increased plasma clearance of androgens. Rather, PFDA must cause the androgenic deficiency by decreasing the secretion of testosterone from the testis. The decrease in testosterone secretion does not appear to result from a decrease in plasma luteinizing hormone (LH) concentrations, because plasma LH concentrations were not significantly altered by PFDA treatment. This finding suggests that PFDA treatment decreases testicular responsiveness to LH stimulation. The observation that PFDA treatment reduced the secretion of testosterone by testes stimulated in vitro with the LH analog human chorionic gonadotropin demonstrates that this is the case. In addition, since plasma LH concentrations did not increase in response to the low plasma androgen concentrations in PFDA-treated rats, we suggest that PFDA disrupts the normal feedback relationship which exists between plasma androgen and LH concentrations.
Article
Inductions by perfluoro-octanoic acid (PFOA) of hepatomegaly, peroxisomal beta-oxidation, microsomal 1-acylglycerophosphocholine acyltransferase and cytosolic long-chain acyl-CoA hydrolase were compared in liver between male and female rats. Marked inductions of these four parameters were seen concurrently in liver of male rats, whereas the inductions in liver of female rats were far less pronounced. The sex-related difference in the response of rat liver to PFOA was much more marked than that seen with p-chlorophenoxyisobutyric acid (clofibric acid) or 2,2'-(decamethylenedithio)diethanol (tiadenol). Hormonal manipulations revealed that this sex-related difference in the inductions is strongly dependent on sex hormones, namely that testosterone is necessary for the inductions, whereas oestradiol prevented the inductions by PFOA.
Article
Treatment of rats with toxic doses of perfluorodecanoic acid (PFDA) results in reduction in feed intake, body weight, serum thyroxine (T4) and triiodothyronine (T3) concentrations, resting heart rates, and body temperatures. Some of these effects resemble changes characteristic of hypothyroidism. Therefore the effects of PFDA on functional thyroid status were examined to relate changes in thyroid status with signs of PFDA toxicity. In the present study, the dose-related effects of PFDA on plasma thyroid hormone concentrations and a number of indices of thyroid status were investigated and compared with signs of PFDA toxicity. Young adult male Sprague-Dawley rats were given single intraperitoneal doses of PFDA (20, 40, or 80 mg/kg), and subsequent changes were evaluated 7 days after dosing. Decreases in body weight and feed intake were used as measures of PFDA toxicity and ranged from minimal to severe. Plasma T4 concentrations and free thyroxine index were drastically reduced at all doses, and these changes were mimicked by pair feeding only at the high dose of PFDA (80 mg/kg). Plasma T3 concentrations were not affected by PFDA treatment, whereas pair feeding at the high-dose level (80 mg PFDA/kg) resulted in a significant reduction (ca. 50% from unlimited-fed control) in T3. Although PFDA caused a dose-dependent decrease in thyroid gland weight which was not completely paralleled by pair feeding, thyroid histology was unremarkable. PFDA treatment resulted in a small decrease in basal metabolic rate (8% at 80 mg PFDA/kg). A greater reduction (ca. 18%) in basal metabolic rate was observed in vehicle-treated controls pair-fed to rats of the 80 mg PFDA/kg dose group. Thermogenesis, as measured by oxygen consumption and body core temperatures, was not greatly affected by PFDA treatment, and these changes were paralleled by pair feeding. Reductions in plasma T4 concentration and free thyroxine index at a low dose of PFDA (20 mg/kg) indicate that PFDA-induced hypothyroxinemia can be dissociated from its overtly toxic effects (i.e., severe hypophagia and body weight loss) observed at higher doses. The results obtained here suggest that despite alterations in plasma thyroid hormone levels there is no consistent pattern of effects on functional thyroid status which could explain the overt toxicity of PFDA.
Article
IT has been assumed that there is only one form of fluoride in serum, the inorganic F ion. It would therefore seem that either the value for serum fluoride which I found (1 M) (refs. 1 and 2) or that found by Singer and Armstrong (7.5 M) (ref. 3) must be in error. While the diffusion method of Singer and Armstrong has been shown to produce erroneous values, the same cannot be said for their ashing and distillation procedure. The evidence that the serum fluoride is about 1 M in a fluoridated community does not rule out the possibility that more fluoride could be made available from serum by ashing; it only indicates that the fluoride in serum able to exchange with added radioactive fluoride can be measured and is 1 M.
Article
It has been suggested that perfluorooctanoic acid occurs in human plasma; however, no method of analysis for this compound in biological samples has been published to date. A method is presented for the analysis of perfluorooctanoic acid in plasma, urine, and liver tissue based on conversion of the acid to its methyl ester followed by separation and quantitation by gas chromatography.
Article
Higher than normal levels of organic fluorine were found in the blood of workers exposed to fluorochemicals in an industrial environment. No ill health effects attributable to exposure to fluorochemicals were found among these workers. The ambient air in the process operation areas in the plant was found to contain measurable amounts of organic fluorine. Through certain modifications in the process steps and improvements in engineering controls. A substantial reduction in the airborne fluorochemical levels within the plant was achieved.
Article
Male Wistar rats and male Duncan Hartley guinea pigs were treated with one i.p. dose of perfluorodecanoic acid (PFDA) resulting in pronounced hepatomegaly in the rat but not the guinea pig. PFDA treatment also resulted in a 4-fold induction of lauric acid 12-hydroxylase activity in the rat but not the guinea pig, indicating induction of the CYP4A subfamily of isoenzymes. Consistent with this latter conclusion, Western blot analysis of rat liver microsomes using an antibody to CYP4A1 and Northern blot analysis of RNA extracts using a CYP4A1 cDNA probe, revealed PFDA-dependent induction of the CYP4A subfamily in the rat but not the guinea pig. Taken collectively, our data has demonstrated that PFDA, like other peroxisome proliferators, is also a CYP4A inducer and conforms to the well-documented species specificity in induction for this class of compound.
Article
Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including planar, mono- and di-ortho congeners and concentrations of DDT were determined in striped dolphins affected by a morbillivirus epizootic in the western Mediterranean in 1990. Extremely high concentrations of PCBs ranging from 94 to 670 micrograms/g (wet wt) were detected in the blubber. Similarly, DDT concentrations were high, between 22 and 230 micrograms/g (wet wt). The concentrations of three non-ortho coplanar PCBs were 43 (3,3',4,4'-T4CB), 6.8 (3,3',4,4',5-P5CB), and 7.8 (3,3',4,4',5,5'-H6CB) ng/g (wet wt), respectively, the highest residue levels reported to date. The estimated 2,3,7,8-TCDD toxic equivalents of non-, mono- and di-ortho PCB congeners in striped dolphins were several times higher than those observed for other marine mammals and humans. Mono-ortho congeners contributed greater 2,3,7,8-TCDD toxic equivalents than non-ortho members. The higher ratio of 3,3',4,4',5,5'-H6CB/3,3',4,4',5-P5CB (IUPAC 169/126) suggested a strong induction of mixed function oxidase enzymes and highlighted the possibility of using this ratio as an index for risk assessment of PCB contamination in marine mammals. Elevated concentrations of PCBs may have played a role in the immune depression in striped dolphins, ultimately leading to the development of morbillivirus disease.
Article
The biogeochemistry of the natural attenuation of petroleum-contaminated ground water was investigated in a field study. The focus of the study was a fire training site located on Tyndall Air Force Base in Florida. The site has been used by the Air Force for approximately 11 years in fire fighting exercises. An on-site above-ground tank of JP-4 provided fuel for setting controlled fires for the exercises. Various amounts of water and aqueous film forming foams (AFFF) were applied to extinguish the fires. The sources of contamination included leaks from pipelines transporting the fuel, leaks from an oil/water separator and runoff and percolation from the fire fighting activities. Previous investigations had identified jet fuel contamination at the site, however, no active remediation efforts have been conducted to date. The goal of this study was to use biogeochemical monitoring data to delineate redox zones within the site and to identify evidence of natural attenuation of JP-4 contamination. In addition to identifying several hydrocarbon metabolites, fluorinated surfactants (AFFF) were detected down-gradient of the hydrocarbon plume.
Article
Perfluorinated fatty acids (PFFAs), such as perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), are known peroxisome proliferators and hepatocarcinogens. A causal link between an increase in the oxidative stress by peroxisomes and tumor promotion has been proposed to explain the hepatocarcinogenicity of PFOA and PFDA. However, the down-regulation of gap junctional intercellular communication (GJIC) has also been linked to the tumor-promoting properties of many carcinogens. Therefore, the effect of PFFAs on GJIC in WB-rat liver epithelial cells was determined. The chain length of the PFFAs tested for an effect on GJIC ranged from 2 to 10, 16 and 18 carbons. Carbon lengths of 7 to 10 inhibited GJIC in a dose-response fashion, whereas carbon lengths of 2 to 5, 16 and 18 did not appreciably inhibit GJIC. Inhibition occurred within 15 min and was reversible, with total recovery from inhibition occurring within 30 min after the removal of the compound from the growth medium. This short time of inhibition suggests that GJIC was modified at the post-translational level. Also, this short time period was not long enough for peroxisome proliferation. The post-translational modification of the gap junction proteins was not a consequence of altered phosphorylation as determined by Western blot analysis. Perfluorooctanesulfonic acid also inhibited GJIC in a dose-response fashion similar to PFDA, indicating that the determining factor of inhibition was probably the fluorinated tail, which required 7-10 carbons. Our results suggest that PFFAs could potentially act as hepatocarcinogens at the level of gap junctions in addition to or instead of through peroxisome proliferation.
Article
The 3M Company manufactures fluorochemicals, which have as a precursor perfluorooctane sulfonyl fluoride (C8F17SO2F). These compounds may be expected to transform metabolically, to an undetermined degree, to perfluorooctane sulfonate (PFOS, C8F17SO3-) as an end-stage metabolite. Subchronic studies in rats and primates indicate a potential for cumulative toxicity with PFOS with the primary effect related to metabolic wasting with hypolipidemia as a consistent finding. Biennial medical surveillance has been offered to the company's fluorochemical production workers located in Decatur, Alabama, and Antwerp, Belgium. In 1995, the mean serum PFOS level, as measured by high-performance liquid chromatography mass spectrometry, for 178 male employees was 2.19 parts per million (ppm; range, 0.00 to 12.83 ppm), and in 1997, for 149 male employees, it was 1.75 ppm (0.10 to 9.93 ppm). Our analyses suggest that among these production employees, there were no substantial changes in serum hepatic enzymes, cholesterol, or lipoproteins associated with PFOS levels less than 6 ppm. It was not possible to derive inferences from the few employees who had serum PFOS levels > or = 6 ppm. These results may be due to the lower levels of serum PFOS measured among these production employees, compared to those suspected to cause effects in laboratory animals.
Article
The in vivo estrogenic activity of the two branched alkylphenols, tert-octylphenol and technical nonylphenol, and the two linear isoforms, n-octylphenol and n-nonylphenol, was compared. The compounds were administered to juvenile rainbow trout (Oncorhynchus mykiss) by either intraperitoneal injection or water exposure and their estrogenic potential was evaluated by ELISA measurements of induced plasma vitellogenin. Intraperitoneal injections (50 mg/kg) of the two branched alkylphenols resulted in a significant vitellogenic response after 12 days whereas no significant induction was seen with the two linear isomers. Water exposure for 9 days to a nominal concentration of 150 micrograms/l of the alkylphenols elicited the same response pattern as seen for the injection experiment. Furthermore, in the present vitellogenin assay tert-octylphenol was giving a higher estrogenic response compared to technical nonylphenol using either of the two exposure routes.
Article
Ammonium perfluorooctanoate is a potent synthetic surfactant used in industrial applications. It rapidly dissociates in biologic media to perfluorooctanoate [CF3(CF2)6CO2-], which is the anion of perfluorooctanoic acid [PFOA, CF3(CF2)6COOH]. PFOA is a peroxisome proliferator known to increase the incidence of hepatic, pancreas and Leydig cell adenomas in rats. The pancreas acinar cell adenomas may be the consequence of a mild but sustained increase of cholecystokinin as a result of hepatic cholestasis. Although no significant clinical hepatic toxicity was observed, PFOA was reported to have modulated hepatic responses to obesity and alcohol consumption among production workers. To further assess these hypotheses, we examined medical surveillance data of male workers involved in ammonium perfluorooctanoate production in 1993 (n=111), 1995 (n=80) and 1997 (n=74). Serum PFOA was measured by high-performance liquid chromatography mass spectrometry methods. Plasma cholecystokinin was measured (only in 1997) by the use of direct radioimmunoassay. Serum biochemical tests included hepatic enzymes, cholesterol and lipoproteins. Serum PFOA levels, by year, were: 1993 (mean 5.0 ppm, SD 12.2, median 1.1 ppm, range 0.0-80.0 ppm); 1995 (mean 6.8 ppm, SD 16.0, median 1.2 ppm, range 0.0-114.1 ppm); and 1997 (mean 6.4 ppm, SD 14.3, median 1.3 ppm, range 0.1-81.3 ppm). Cholecystokinin values (mean 28.5 pg/ml, SD 17.1, median 22.7 pg/ml, range 8.8-86.7 pg/ml) approximated the assay's reference range (up to 80 pg/ml) for a 12 hour fast and were negatively, not positively, associated with employees' serum PFOA levels. Our findings continue to suggest there is no significant clinical hepatic toxicity associated with PFOA levels as measured in this workforce. Unlike a previously reported observation, PFOA did not appear to modulate hepatic responses to either obesity or alcohol consumption. Limitations of these findings include: 1) the cross-sectional design as only 17 subjects were common for the three surveillance years; 2) the voluntary participation that ranged between 50 and 70 percent; and 3) the few subjects with serum levels > or = 10 ppm.
Article
Elimination in urine and feces was compared between four perfluorinated fatty acids (PFCAs) with different carbon chain length. In male rats, perfluoroheptanoic acid (PFHA) was rapidly eliminated in urine with the proportion of 92% of the dose being eliminated within 120 h after an intraperitoneal injection. Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) was eliminated in urine with the proportions of 55, 2.0 and 0.2% of the dose, respectively. By contrast, four PFCAs were eliminated in feces with the proportion of less than 5% of the dose within 120 h after an injection. In female rats, the proportions of PFOA and PFNA eliminated in urine within 120 h were 80% and 51% of the dose, respectively, which were significantly higher compared with those in male rats. There was the tendency that PFCA with longer carbon chain length is less eliminated in urine in both male and female rats. Fecal elimination of PFCAs was not different between PFCAs in female rats and comparable to those in male rats. The rates of biliary excretion of PFCAs in male rats were slower than those in female rats. Sex-related difference in urinary elimination of PFOA was abolished when male rats had been castrated. On the contrary, treatment with testosterone suppressed the elimination of PFOA in urine in both castrated male rats and female rats. The effect of testosterone was in a time- and dose-dependent manner. These results suggest that PFCAs are distinguished by their carbon chain length by a renal excretion system, which is regulated by testosterone.
Article
Here we report, for the first time, on the global distribution of perfluorooctanesulfonate (PFOS), a fluorinated organic contaminant. PFOS was measured in the tissues of wildlife, including, fish, birds, and marine mammals. Some of the species studied include bald eagles, polar bears, albatrosses, and various species of seals. Samples were collected from urbanized areas in North America, especially the Great Lakes region and coastal marine areas and rivers, and Europe. Samples were also collected from a number of more remote, less urbanized locations such as the Arctic and the North Pacific Oceans. The results demonstrated that PFOS is widespread in the environment. Concentrations of PFOS in animals from relatively more populated and industrialized regions, such as the North American Great Lakes, Baltic Sea, and Mediterranean Sea,were greaterthan those in animals from remote marine locations. Fish-eating, predatory animals such as mink and bald eagles contained concentrations of PFOS that were greater than the concentrations in their diets. This suggests that PFOS can bioaccumulate to higher trophic levels of the food chain. Currently available data indicate that the concentrations of PFOS in wildlife are less than those required to cause adverse effects in laboratory animals.
Article
Since the early 1980s, there has been a steady increase in the use of nonvolatile fluorinated organic compounds for a variety of industrial and commercial applications. The industrial use of these relatively stable compounds has initiated debate over the fate of fluorochemicals in the environment and, ultimately, the bioavailability of these compounds. In this manuscript, we present quantitative results from a study of 65 human sera samples purchased from biological supply companies that provide characterization of specific organic fluorochemicals present in the sera of nonindustrially exposed humans. Summed together, the compound-specific characterization data reported here agree closely with levels of nonspeciated organic fluorine that were originally reported to be present in sera in 1970. The compound-specific method for the extraction of extremely low levels of several commercial organic fluorochemicals from sera and liver with quantitative detection by negative ion electrospray tandem mass spectrometry described represents a robust, previously undescribed approach to quantifying specific organic fluorochemicals in biological matrices.
Article
The determination of sub-ppm concentrations of aqueous perfluoroalkylsulfonate (PFS) anions, including perfluorooctylsulfonate (PFOS), has been accomplished with a relatively simple mass spectrometric procedure that does not require extraction of the analytes into an organic solvent or a chromatographic separation prior to injection into the negative-ion electrospray ionization mass spectrometer. Sample pretreatment was minimized and consisted of dilution of the aqueous samples of groundwater, surface water, tap water, and distilled water with acetonitrile, addition of dodecylsulfate (DDS) as an internal standard, and, in some cases, addition of known amounts of perfluorobutylsulfonate (PFBS) or PFOS for standard-addition experiments. The linear-response range for PFOS is 25.0 µg L−1 to 2.5 mg L−1. The lower limit of this range is three orders of magnitude lower than an equally straightforward chromatographic method. The relative errors for standard aqueous solutions containing only 25.0 µg L−1 and 2.5 mg L−1 PFOS are ±14% and ±7%, respectively, with 133 µg L−1 DDS as the internal standard. The detection limit and quantification limit for PFOS in these standards are 5.0 µg L−1 and 25.0 µg L−1, respectively. Six different PFS anions, containing three to eight carbon atoms, were identified and quantified in an aqueous film-forming foam (AFFF) formulation using the method of standard additions. Two alkylsulfate anions and two perfluoroalkylcarboxylate anions were also identified in the AFFF formulation.
Article
Perfluorinated surfactants have emerged as priority environmental contaminants due to recent reports of their detection in environmental and biological matrices as well as concerns regarding their persistence and toxicity. In June 2000, 22000 L of fire retardant foam containing perfluorinated surfactants was accidentally released at L. B. Pearson International Airport, Toronto, ON, and subsequently entered into Etobicoke Creek, a tributary to Lake Ontario. A suite of analytical tools that include liquid chromatography/tandem mass spectrometry (LC/MS/MS) and 19F NMR were employed to characterize fish (common shiner, Notropus cornutus) and surface water samples collected following the discharge of the perfluorinated material. Total perfluoroalkanesulfonate (4, 6, and 8 carbons) concentrations in fish liver samples ranged from 2.00 to 72.9 microg/g, and total perfluorocarboxylate (5-14 carbons) concentrations ranged from 0.07 to 1.02 microg/g. In addition to fish samples, total perfluoroalkanesulfonate (6 and 8 carbons) concentrations were detected in creek water samples by LC/MS/MS over a 153 day sampling period with concentrations ranging from <0.017 to 2260 microg/L; perfluorooctanoate concentrations (<0.009-11.3 microg/L) were lower than those observed for the perfluoroalkane-sulfonates. By 19F NMR, the total perfluorinated surfactant concentrations in surface water samples ranged from < 10 to 17000 microg/L. A bioaccumulation factor range of 6300-125000 was calculated for perfluorooctanesulfonate, based on concentrations in fish liver and surface water. The residence time of perfluorooctanesulfonate in Etobicoke Creek as well as the high bioaccumulation in fish liver suggests that perfluorinated surfactants will persist and bioaccumulate following release into the aquatic environment.
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