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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... Perfluorooctane sulfonate (PFOS) has been a focus of concern because of its persistence in the environment (Giesy and Kannan 2002), retention in human body (Olsen et al. 2007), and toxicities (Giesy and Kannan 2002;Ankley et al. 2004). Previous studies have shown that PFOS is ubiquitously detected in the environment, even in remote arctic areas (Giesy and Kannan 2001;. ...
... Perfluorooctane sulfonate (PFOS) has been a focus of concern because of its persistence in the environment (Giesy and Kannan 2002), retention in human body (Olsen et al. 2007), and toxicities (Giesy and Kannan 2002;Ankley et al. 2004). Previous studies have shown that PFOS is ubiquitously detected in the environment, even in remote arctic areas (Giesy and Kannan 2001;. ...
... PFOS is chemically and thermally stable and is considered to be the terminal degradation product of many perfluorochemicals (Organization for Economic Co-operation and Development 2002). Because of the potential bioaccumulation and the possible negative impact on the total environment and ultimately humans (Giesy and Kannan 2002;Beach et al. 2006;Olsen et al. 2007), it is urgent to investigate the environmental fate of PFOS. Several direct and indirect sources of PFOS emission to the environment have been reported, such as manufacturing processes in the polymer and electronic industries (Prevedouros et al. 2006), in the degradation of volatile precursors (Ellis et al. 2004;Dinglasan et al. 2004;Lange 2000) or in the release of treated wastewaters (Boulanger et al. 2005;Schultz et al. 2006;Sinclair and Kannan 2006;Becker et al. 2008). ...
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The distribution of perfluorooctane sulfo-nate (PFOS) was investigated in a total of 15 water and sediment samples from the Yellow River Estuary, China in April 2011. The results indicated that the concentrations of PFOS in the water and sediment samples averaged 157.5 ng/L and 198.8 ng/g and ranged from 82.30 to 261.8 ng/L and 75.48 to 457.0 ng/g, respectively. The concentrations of PFOS in the sediment column increased from 45.32 to 379.98 ng/g with the decrease of the sampling depth, which showed that the increased PFOS pollution in the sediment appeared in this region in over recent years. The distribution coefficient (K d) of PFOS between water and sediment linearly increased from 0.37 to 4.80 L/g as the salinity (S‰) increased from 0.18 to 4.47. Correlation analysis revealed that K d was significantly and positively correlated to the contents of total organic carbon and clay of the sediment, and salinity. Therefore, salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. The results of this study showed that the estuary was an important sink for PFOS and suggested that PFOS might be carried with the river water and transported for long distances before it reached to the sea and largely scavenged to the sediment in the estuaries due to the change in salinity.
... Perfluoroalkyl substances (PFASs) are a category of compounds characterized by the fully fluorinated aliphatic chain connecting with one hydrophilic head group [1]. Due to their remarkable chemical stability, fire resistibility, hydrophobicity and lipophobicity, PFASs have been extensively used in multiple industrial and commercial fields during the past several decades [2][3][4][5]. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are the best-known PFASs. However, as increasing knowledge about their environmental persistence and toxicities [6][7][8], PFOA and PFOS have been banned for production or restricted for use by the Stockholm Convention. ...
Article
Herein, we developed a self-assembled micelle system to decompose/defluorinate HFPO-TA (an alternative perfluoroalkyl substances (PFASs)) under ambient conditions by using three hydroxyphenylacetic acids (2-HPA, 3-HPA, 4-HPA) as hydrated electron precursors under UV irradiation, and using cationic surfactant cetyl trimethyl ammonium bromide (CTAB) to construct the micelle structure. The formed HPAs/CTAB/HFPO-TA micelles were well characterized. All the three micelle systems could efficient destruct HFPO-TA, while 2-HPA/CTAB/HFPO-TA self-assembled micelle showed the best stability under a wide pH range from 4 to 10 attributing to its tighter micelle structure and lower surface charge density. Moreover, natural organic matter (< 10 mg L⁻¹) plays little inhibition for the 2-HPA/CTAB/HFPO-TA system. This novel ternary micelle system not only maintains the high efficiency under the conditions of oxygen enrichment, but also keeps well performance in varied pH conditions. The high decomposition/defluorination efficiency and anti-interference capability of the 2-HPAs/CTAB/HFPO-TA micelle system make it a promising technology for treating the PFASs contaminating wastewater.
... Substances such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were commonly used in AFFF formulations (Buck et al. 2011;Place and Field 2012) and have been detected in a wide variety of environmental media and human and animal tissues around the world Kannan 2001, 2002). These compounds and PFAS in general are resistant to degradation and readily move within and among components of different ecosystems, causing both public and environmental health concerns (Giesy and Kannan 2002;Norwegian Pollution Control Authority 2008). ...
Article
Few studies have determined the toxicity of perfluoralkyl substances to aquatic invertebrates. Here, we exposed Chironomus dilutus to six different perfluoroalkyl substances (PFAS) to assess single chemical toxicity and relative or proportional toxicity among substances. A 10 d range finding test was conducted to inform 20 d assays for the following PFAS: (perfluorooctane sulfonate [PFOS], perfluorooctanoic acid [PFOA], perfluorononanoic acid [PFNA], perfluorobutanesulfonic acid [PFBS], perfluorohexanesulfonic acid [PFHxS], and perfluoroheptanoic acid [PFHpA]). A 20 d binary mixture study of PFOS+PFHxS followed the single chemical tests. Measurement endpoints 20 d tests included larval survival and biomass. Log‐logistic concentration response models were used to estimate 10, 20, and 50 percent effects concentrations for PFOS, PFHxS, and PFOA. Survival EC50s for PFOS, PFHxS, and PFOA were 2.49 µg/L, 913 µg/L, and 192,000 µg/L, respectively, while survival EC20s were 1.70 µg/L, 3,860 µg/L, 119,000 µg/L for PFOS, PFHxS, and PFOA respectively. Biomass as a combined survival and growth endpoint resulted in EC20s of 1.89 µg/L, 896 µg/L, 137,000 µg/L for PFOS, PFHxS, and PFOA, respectively. Maximum concentrations tested (NOECs) for PFNA, PFBS, and PFHpA were two to three orders of magnitude greater than the PFOS EC50s and showed no toxicity to C. dilutus, even at exposure concentrations well above what would be considered environmentally relevant. The binary mixture of 2.5 ug/L PFOS+1,000ug/L PFHxS showed reduced survival compared to controls and some indication of potential additive or synergistic interaction between PFOS and PFHxS. Overall, this study supports previous studies showing PFOS to be the most toxic PFAS to aquatic life and suggests that PFOS could be more toxic to freshwater midge than previously reported. This article is protected by copyright. All rights reserved.
... These unknown precursors can degrade into known PFAS [36]. PFOS and PFOA ( Fig. 1) have been studied the most since they have been manufactured the longest [37,38]. The U.S. EPA lifetime health advisory level was determined based on exposure studies of these two PFAS [39]. ...
Article
Per- and polyfluoroalkyl substances (PFAS) are a class of compounds that have become environmental contaminants of emerging concern. They are highly persistent, toxic, bioaccumulative, and ubiquitous which makes them important to detect to ensure environmental and human health. Multiple instrument-based methods exist for sensitive and selective detection of PFAS in a variety of matrices, but these methods suffer from expensive costs and the need for a laboratory and highly trained personnel. There is a big need for fast, inexpensive, robust, and portable methods to detect PFAS in the field. This would allow environmental laboratories and other agencies to perform more frequent testing to comply with regulations. In addition, the general public would benefit from a fast method to evaluate the drinking water in their homes for PFAS contamination. A PFAS sensor would provide almost real-time data on PFAS concentrations that can also provide actionable information for water quality managers and consumers around the planet. In this review, we discuss the sensors that have been developed up to this point for PFAS detection by their molecular detection mechanism as well as the goals that should be considered during sensor development. Future research needs and commercialization challenges are also highlighted.
... Per-and polyfluoroalkyl substances (PFASs) are extensively used in industrial and household products due to their excellent stability and unique hydrophobic and oleophobic properties (Giesy and Kannan, 2002). PFASs are ubiquitous in various environmental compartments throughout the world (Lindstrom et al., 2011). ...
Article
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Polyfluoroalkyl phosphate esters (PAPs) are high production volume surfactants used in the food contact paper and packaging industries. They are prone to partition to soil due to their strong hydrophobicity and may biotransform into recalcitrant perfluoroalkyl carboxylic acids (PFCAs); little is known about their fate and behaviors in terrestrial organisms. Here, geophagous earthworms (M. guillelmi) were exposed to 6:2 fluorotelomer phosphate diester (6:2 diPAP)-contaminated soil to examine tissue-specific accumulation and biotransformation. 6:2 diPAP quickly accumulated in M. guillelmi with the highest biota-soil-accumulation factor (BSAF) in the gut, followed by the organs, skin, and body fluid. The total amount of 6:2 diPAP accumulated in the skin was the highest due to its high mass content. These results indicated that skin absorption and gut processes were two major pathways for earthworms to accumulate 6:2 diPAP from soil. In vitro desorption experiments indicated that the gut digestion fluid greatly promoted the desorption of 6:2 diPAP from the soil and enhanced its bioavailability. Degradation of 6:2 diPAP in the soil was stimulated when the earthworm appeared. In contrast to the soil, a more extensive transformation occurred in the earthworm. Perfluorohexanoic acid (PFHxA) was the primary phase Ⅰ product, followed by perfluoropentyl propanoic acid (FPePA), perfluoropentanoic acid (PFPeA), 2-perfluorohexyl ethanoic acid (FHEA), and perfluoroheptanoic acid (PFHpA), which confirmed the occurrence of α- and β-oxidation in earthworms. For the first time, a new phase II product, namely, a 6:2 fluorotelomer alcohol sulfate conjugate, was identified in earthworms at unexpectedly high levels, which might be the primary way earthworms eliminate 6:2 diPAP. Both in vivo and in vitro experiments suggested that 6:2 diPAP experienced faster and more extensive biotransformation in the gut than in the organs. This work sheds light on the bioaccumulation and biotransformation of 6:2 diPAP in terrestrial invertebrates, providing strong evidence of indirect sources of PFCAs in the environment.
... ( 13 18 (Frisbee et al., 2009Giesy and annan, 2002Prevedouros et al., 2006. Interestingly, Region IV A, being deemed as the industrial belt of the country, is home to several com panies involved in these industries (Oxford Business Group, 2016). ...
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Several studies have reported exposure of humans to various endocrine disrupting chemicals (EDCs) worldwide. However, there is a lack of data regarding EDC exposures in humans living in Southeast Asian countries, such as the Philippines. Hence, this study measured levels of 41 EDCs in women residing in the Greater Manila Area, home to the second largest city in Southeast Asia. Urine samples from women with versus without breast cancer were analyzed for 11 phthalate metabolites, 8 environmental phenols, and 10 bisphenols, while serum samples were analyzed for 12 perfluoroalkyl substances (PFAS). Out of the four groups of EDCs analyzed, PFAS were significantly associated with breast cancer (adjusted OR = 13.63, 95% CI: 3.24–94.88 p-trend = 0.001 for PFDoA; adjusted OR = 9.26, 95% CI 2.54–45.10, p-trend = 0.002 for PFDA; and adjusted OR = 2.66, 95% CI: 0.95–7.66, p-trend = 0.004 for PFHxA). Long-chain PFAS levels were positively correlated with age and were significantly higher in women from Region IV-A, a heavily industrialized region, than from the National Capital Region. Overall, this study showed baseline information regarding the level of EDCs in Filipinas, providing a glimpse of EDC exposure in women living in a megalopolis city in Southeast Asia.
... Widespread use of per-and polyfluoroalkyl substances (PFAS) in manufacturing processes, consumer goods, and firefighting foams has widely contaminated municipal drinking water supplies at concentrations exceeding recommended exposure levels [1][2][3][4][5]. The use of aqueous film-forming foams (AFFF) for firefighting training has particularly contributed to the water contamination problem [6]. ...
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Effective technologies are needed for the destruction of per- and polyfluoroalkyl substances (PFAS). One promising technology is supercritical water oxidation (SCWO), which can be accommodated in batch or continuous reactors. Many PFAS-laden wastes consist primarily of solid particles, and batch SCWO processing may offer safe end-of-life PFAS destruction for these feedstocks. In this study, perfluorooctanesulfonate (PFOS) is reacted via supercritical water oxidation in a batch reactor at temperatures between 425 and 500 °C and residence times from 0 to 60 min, to determine the effect of both parameters on the extent of destruction and defluorination. Analysis of liquid products via targeted LC-QToF-MS does not indicate production of intermediate fluorocarbons. However, a low fluorine mass balance at temperatures of 425 and 450 °C may indicate the existence of fluorinated species in the gaseous and/or liquid product which are not detected by targeted analysis. Destruction and defluorination efficiencies are determined for each tested condition, with a maximum 70.0% PFOS destruction and 78.2% defluorination achieved after 60 min of reaction at 500 °C.
... This strong bond coupled with the presence of three nonbonding electron pairs on each fluorine atom and the effective shielding of the carbon atoms by fluorine confer relative stability on PFAS. Therefore, PFAS are resistant to many degradation processes involving acids, bases, reductants, oxidants, microbes, photolytic and metabolic process and they are also non-flammable [4,58]. ...
Article
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The increase in the presence of highly recalcitrant poly- and per- fluoroalkyl substances (PFAS) in the environment, plant tissues and animals continues to pose serious health concerns. Several treatment methods such as physical, biological and chemical processes have been explored to deal with these compounds. Current trends have shown that the destructive treatment processes, which offer degradation and mineralization of PFASs, are the most desirable process among researchers and policy makers. This article, therefore, reviews the degradation and defluorination processes, their efficiencies and the degradation mechanism of photon-based processes. It shows that high degradation and defluorination efficiency of PFASs could be achieved by photon driven processes such as photolysis, photochemical, photocatalysis and photoreduction. The efficiency of these processes is greatly influenced by the nature of light and the reactive radical generated in the system. The limitation of these processes, however, include the long reaction time required and the use of anoxic reaction conditions, which are not obtainable at ambient conditions.
... Perfluoroalkyl acids (PFAA) are artificial chemicals that possess characteristics of thermal resistance, physical and chemical stability, and repellency of water and oil (Giesy and Kannan 2002;OECD 2018). PFAA have been widely used for more than 60 years in manufacturing industries and commercial products, such as metal plating, fluoropolymer manufacturing, aqueous firefighting foams (AFFF), textile, paper, and water repellent items. ...
Article
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The dust on indoor and outdoor surfaces of the window glasses were collected using sterile cotton balls in 11 cities from China. Two sampling campaigns were conducted with the time interval of 7 days to investigate the accumulation especially during the Spring festival holidays. Twenty-nine perfluoroalkyl acids (PFAA) were quantified to investigate concentration, composition, and toddlers’ exposure. The concentrations of ∑PFAA ranged from no detection (nd) to 43 ng/m² (mean 8.9 ± 10 ng/m²). Perfluorobutanoic acid (PFBA) was detected in 78% samples and accounted for 55 ± 21% of ∑PFAA concentrations. 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and hexafluoropropylene oxide dimer acid (HFPO-DA) were detected in more than 50% samples indicating the use of alternatives. Fluorotelomer carboxylic acid (FTCA) and fluorotelomer unsaturated acid (FTUCA) were found in the dust, implying the degradation of fluorotelomer alcohols (FTOH). The highest concentration of ∑PFAA (43 ng/m²) was found in outdoor dust from Xinzhou, Shanxi Province. Higher ∑PFAA concentrations were found in indoor dust than outdoor in 6 paired samples (3 from Feb. 14 and 3 from Feb. 21). In Tianjin and Handan, the concentrations of ∑PFAA from outdoor surfaces were higher in sampling campaign I (SC I, Feb. 21) than in sampling campaign II (SC II, Feb. 14), implying intensive outdoor release. The exposure of 2-year-old toddlers to PFAA via hand-to-mouth ingestion and dermal absorption was estimated; the mean values of intake were 2.1 and 1.5 pg/kg body weight, respectively, assuming an exposure time of 1 h.
... The persistence of PFAS in the environment reflects their stability to high heat, as well as resistance to chemical and microbial degradation (Krafft and Riess 2015). The multiple carbon-fluorine bonds present in these compounds have been connected to their environmental recalcitrance (Giesy and Kannan 2002). ...
Article
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Perfluorobutanoic acid (PFBA), one of the short-chain replacement perfluoroalkyl substances, has been shown to accumulate in plants. The potential of PFBA to modulate the developmental cycle of the beet armyworm, Spodoptera exigua, a polyphagous pest, was investigated. Second-instar larvae were fed with PFBA-spiked artificial diets and leaves from soybean plants grown with PFBA-spiked irrigation water. Spiked PFBA concentrations were 200 μg/kg for the artificial diet, whereas 405 to 15,190 ng/kg accumulated in the soybean leaves. The larvae fed with the PFBA-spiked diet showed a significant increase in weight gain compared with the controls over a 7-day exposure period. A similar weight gain trend was observed with larvae fed with the PFBA-containing soybean leaves, with the dose–response data fitting into a Brain-Cousens hormesis model with a 57% stimulation over controls. The artificial diet treatments showed 66.7% metamorphosed larva to pupa at 9 days after exposure (dpe) compared with 33.3% of the controls. The adult emergence at 16-dpe followed a similar trend with 57.7% and 33.3%, respectively, for the exposed and control groups. The duration of transition from larvae to adults was more symmetrical and 0.5 day faster for the exposed groups over controls. The beet armyworm caused more damage on leaves from the PFBA exposed plants in a nonmonotonic dose–response manner. The results suggest PFBA may have a stimulatory impact on some hormonal signaling pathways at low doses.
... In our studies, we focused on radiation chemistry of aqueous solutions containing perfluorooctanoate anions (PFOA, C 7 F 15 COO − , Fig. 1). PFOA is used in firefighting foam, for coating outdoor clothing, as a surfactant in the emulsion polymerization of fluoropolymers and in other industrial synthesis (Giesy and Kannan, 2002). Since pK a value of the perfluorooctanoic acid is equal to 3.8(1) (Burns et al., 2008), it exists only in strongly acidic solutions. ...
Article
The mechanism of high-energy radiation induced degradation of perfluorooctanoate anion (PFOA, C7F15COO⁻) was investigated in aqueous solutions. Identification and quantification of transient species was performed by pulse radiolysis and of final products by gas and ion chromatography, electrochemical method using fluoride ion-selective electrode and ESI-MS after γ-radiolysis. Experimental data were further supported by kinetic simulations and quantum mechanical calculations. Radiation induced degradation of PFOA includes as a primary step one-electron reduction of PFOA by hydrated electrons (e⁻aq) resulting in formation of [C7F15COO⁻]●−. The rate constants of this reaction were found to be in the range 7.7 × 10⁷−1.3 × 10⁸ M⁻¹s⁻¹ for ionic strength of the solutions in the range 0.01–0.1 M and were independent of pH of the solutions. At pH > 11 [C7F15COO⁻]●− tends to defluorination whereas at lower pH undergoes protonation forming [C7F15COOH]•−. A sequence of consecutive reactions involving [C7F15COOH]•− leads to PFOA regeneration what explains a high radiation resistance of PFOA at moderately acidic solutions. A simultaneous presence of oxidizing transient species (●OH) in the irradiated system enhanced decomposition of (C7F14)·COO⁻ as well as [C7F15COOH]•−. The key steps in this complex radical mechanism are the reactions of both these radical anions with ●OH leading to semi-stable products which further undergo consecutive thermal reactions. On the other hand, direct reactions of PFOA with ●OH and ●H were found to be relatively slow (7 × 10³ and <4 × 10⁷ M⁻¹s⁻¹, respectively) and do not play relevant role in PFOA degradation. Collected for the first time results, such as dependence of selected reaction rate constants and selected products radiation chemical yields on pH as well as finding of several semi-stable products, missing in previous studies, indicate incompleteness of published earlier reaction pathways of PFOA degradation. The presented overall mechanism explains experimental results and verifies previously suggested mechanisms found in the literature.
... PFOS is typically the dominant PFAS detected in environmental and biological samples, which can be explained by the extensive historical use of PFOS and its precursors, which are ultimately transformed to PFOS, an end stage metabolite/degradation product (Giesy and Kannan, 2002;Moody et al., 2003;Barzen-Hanson and Field, 2015). The highest reported concentration of PFOS in fish is 73,200 ng/g. ...
... Perfluorooctanoic acid (PFOA), in particular, is mostly employed as a processing agent in the production of high-capacity fluoropolymers such as polytetrafluoroethylene used in the manufacture of water-repellent clothing and nonstick coatings (Prevedouros et al., 2006). Due to their wide detection , environmental persistence (Giesy and Kannan, 2002), high bioaccumulation and potential effects (Ahrens and Bundschuh, 2014), PFASs have received wide attention from the scientific community and the public. Given that phytoremediation is cost effective and environmentally friendly, it is skilled at removing persistent organic pollutants from surface water (Reinhold et al., 2010;Sun et al., 2010). ...
Article
Perfluoroalkyl substances (PFASs) have been widely studied by researchers due to their environmental persistence, chemical stability and potential toxicity. Some researchers have reported the physiological and biochemical toxicity of PFASs on plants through traditional and innovative methods; however, the changes in biological macromolecules caused by PFASs are rarely studied. Here, Fourier transform infrared spectroscopy (FTIR) was used to study how exposure to perfluorooctanoic acid (PFOA) alters the structure and function of biomolecules of the wetland plant Alisma orientale. Biomass results showed that PFOA had negative effects on plant growth. FTIR results showed that PFOA could result in changes in the structures, compositions, and functions of lipids, proteins and DNA in plant cells. In the treatment groups, the ratios of CH3 to lipids and carbonyl esters to lipids increased compared with the control, while the ratios of CH2 to lipids and olefinicCH to lipids decreased, which indicated lipid peroxidation caused by PFOA exposure. Changes in the compositions and secondary structures of proteins were also found, which were indicated by the decreased ratio of amide I to amide II and the increased ratio of β-sheet to α-helix in the treatment groups compared to the control. Moreover, PFOA affected the composition of DNA by promoting the B- to A-DNA transition. These results showed that the mechanism of PFOA toxicity toward plants at the biochemical level could be illustrated by FTIR.
... It has been widely used in chemical, textile, coating, leather, papermaking, fire-fighting foam, and other fields. It exhibits exceptionally high chemical stability and difficult to degrade through physical, chemical, and biological processes (Giesy and Kannan, 2002). Owing to its degradation-resistant nature (Kissa, 2001), PFOS has been frequently detected in various environmental and biological matrices including air, water, sediment, soils, wildlife and humans (Adams et al., 2008;Ao et al., 2019;Liu et al., 2009Liu et al., , 2019Sun et al., 2018). ...
Article
Perfluorooctane sulfonate (PFOS) potentially adsorbs on the surface of suspended sediment (SPS), which can develop a toxic “pool” bioavailable to benthic organisms. In this study, the freshwater clam Corbicula fluminea was employed as a zoobenthos model to study the effects of SPS (collected from the Yellow River) on the bioaccumulation and toxicity (from the molecular level to cellular and physiological levels) caused by PFOS exposure. Besides, the enhanced integrated biomarker response (EIBR) system was applied as an index to evaluate the in-depth toxic effects of PFOS and SPS single and co-exposure at various treatment levels. Our results demonstrated that PFOS-SPS co-exposure (at sub-lethal doses of PFOS) significantly increased the bioaccumulation of PFOS, and induced the elevated levels of reactive oxygen species (ROS), the significantly increased activities of superoxide dismutase (SOD) and catalase (CAT) enzymes, the significantly increased content of malondialdehyde (MDA), and the significantly upregulated expression levels of sod, selenium-dependent glutathione peroxidase (se-gpx), heat shock protein 22 (hsp22), heat shock protein 40 (hsp40) and cytochrome P450 30 (cyp30) genes. Further, the co-exposure induced the significantly higher histopathological alterations in the gonads and digestive glands, and even elevated the inhibition of siphoning behavior in clams. In addition, the EIBR index also revealed the highest values for PFOS and SPS co-exposure, compared to the individual SPS or PFOS exposure. The results indicated that at high levels of PFOS exposure (especially at 1000 μg/L), the presence of SPS might increase the generation of ROS by influencing the bioaccumulation of PFOS, which enhanced the toxicity of PFOS to C. fluminea. These results potentially provide basic information for the comprehensive evaluation of the toxic effects of PFOS on benthos in a multi-sediment river ecosystem.
... The particular concern with regards to the extraordinary environmental persistence of PFAS is based on the environmental recalcitrance of PFAA and the production of PFAA from other PFAS. PFAA are resistant to breakdown by typical environmental transformation processes, including hydrolysis, photolysis, biodegradation, and metabolism, with half-lives on the order of years-decades (Giesy and Kannan, 2002;Giesy et al., 2006). Certain PFAA have the capacity for long-range transport via ocean currents and air, and have been detected in water, sediment, ice, and biota of remote locations distant from known sources (MacInnis et al., 2019;Muir et al., 2019;Pickard et al., 2018). ...
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Perfluoroalkyl substances (PFAS), including perfluorooctanoic acid (PFOA), are industrial chemicals that are of concern due to their environmental presence, persistence, bioaccumulative potential, toxicity, and capacity for long-range transport. Despite a large body of research on environmental exposure, insufficient chronic aquatic toxicity data exist to develop water quality targets for clean-up of federal contaminated sites in Canada. Thus, our objective was to assess the aqueous toxicity of PFOA in chronic tests with Hyalella azteca (amphipod) and early-life stage tests with Pimephales promelas (fathead minnow). Toxicity data were analyzed based on measured PFOA concentrations. Amphipod exposures were 42 d (0.84-97 mg/L) and examined survival, growth, and reproduction. Fathead minnow exposures were 21 d (0.010-76 mg/L), which encompassed hatching (5 d) and larval stages until 16 d post-hatch; endpoints included hatching success, deformities at hatch, and larval survival and growth. Amphipod survival was significantly reduced at 97 mg/L (42-d LC50 = 51 mg/L), but growth and reproduction were more sensitive endpoints (42-d EC50 for both endpoints = 2.3 mg/L). Fathead minnows were less sensitive than amphipods, exhibiting no significant effects in all endpoints with the exception of uninflated swim bladder, which was significantly higher at 76 mg/L (15%) than controls (0%). Maximum concentrations of PFOA are generally in the ng/L range in global surface waters, but can reach the μg/L range in close proximity to major source inputs; therefore, environmental concentrations are well below those that caused toxicity in the current study. Our data will provide valuable information with which to assess the risk of PFOA at contaminated sites, and to set a target for site remediation.
... This in turn is the result of civilizational and industrial development, and urbanization as anthropogenic sources play the most important role in the emission of these xenobiotics. These compounds are widely used in industry as surfactants, impregnants, paint additives [10], pesticides, fertilizers [19], in transformers and many other household products [6]. Therefore, human exposure to contact with these compounds is relatively high. ...
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The purpose of the work was to review the literature and characterize organic micropollutants from the group of perfluorinated surfactants - PFAS. It is a result of the proposal to include these compounds in the new Water Directive on the list of compounds which control in drinking water will be required and subject to inspection. The group of these organic bonds includes several thousand compounds in which fluorine is linked to the (straight or branched) chain of aliphatic hydrocarbons instead of hydrogen. The article describes the permissible concentrations of PFAS in waters, the properties of these compounds, their potential impact on organisms, concentrations identified in waters, and indicates the need to limit the emissions of these compounds to surface waters. This is an important problem from the point of view of these compounds’ impact on organisms and the fact that such waters are often a source of water supply for the national economy, including consumption by the population.
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Although recent epidemiologic studies have focused on some of the health effects of perfluoroalkyl substance (PFASs) exposure in humans, the associations between PFASs exposure and the lipidome in children are still unclear. The purpose of this study was to assess lipid changes in children to understand possible molecular events of environmental PFASs exposure and suggest potential health effects. A total of 290 Taiwanese children (8-10 years old) were included in this study. Thirteen PFASs were analyzed in their serum by high-performance liquid chromatography-tandem mass spectrometry (LC-MS). MS-based lipidomic approaches were applied to examine lipid patterns in the serum of children exposed to different levels of PFASs. LC coupling with triple quadrupole MS technology was conducted to analyze phosphorylcholine-containing lipids. Multivariate analyses, such as partial least squares analysis along with univariate analyses, including multiple linear regression, were used to analyze associations between s exposure and unique lipid patterns. Our results showed that different lipid patterns were discovered in children exposed to different levels of specific PFASs, such as PFTrDA, PFOS, and PFDA. These changes in lipid levels may be involved in hepatic lipid metabolism, metabolic disorders, and PFASs-membrane interactions. This study showed that lipidomics is a powerful approach to identify critical PFASs that cause metabolite perturbation in the serum of children and suggest possible adverse health effects of these chemicals in children.
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Perfluoroalkyl substances (PFASs) are a group of synthetic organic chemicals that are persistent in the environment as well as in wildlife and human body. Further, PFASs are considered as persistent organic pollutants. PFASs have been extensively used in many industrial and consumer products over the past several decades and, therefore, they are found in various environmental matrices. A large number of studies during the past decades have reported the toxic effects of these compounds on the male reproductive health including damage to the seminiferous tubules, changes in reproductive hormones level, and low sperm counts and the molecular mechanism(s) involved in such effects. In the present review, we have summarized the reproductive toxicity of some PFASs, namely, perfluorooctanoic acid, perfluorooctane sulfonate, perfluorododecanoic acid, and perfluorononanoic acid in the male. This article briefly describes the findings on PFASs which may attract the attention of the reproductive toxicologists to examine the potential risk to the male reproductive health because of the continued contamination of the environment by these compounds.
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The Mediterranean is a region of substantial agriculture production that faces concurrent environmental stresses and freshwater pollution given the occurrence of emerging contaminants (ECs). Among these pollutants, the surface-active substances have been suggested to enhance the bioavailability of other ECs. This research evaluates a comparative uptake and translocation assessment of irrigation exposure to atenolol (ATN, 60 µg/L), carbamazepine (CBZ, 60 µg/L) and triclosan (TCS, 30 µg/L) alone vs. these combined with perfluorooctanesulfonic acid (PFOS, 10 µg/L) under semifield (i.e., soil experimental set) vs. hydroponics (i.e., soilless experimental set) growing conditions with lettuce, radish and tomato plants. Both experimental sets revealed efficient root uptake and translocation for the three ECs regardless of their co-existence with PFOS. The overall results of the uptake and translocation of the ECs in the lettuce and tomato plants suggested a simultaneous treatment-plant organ interaction, which was not affected by PFOS being present in both experimental sets. PFOS in irrigation water did not increase cellular perviousness to the other three ECs. These observations support the hypothesis of factors other than PFOS being responsible for the differential bioaccumulation and translocation potentials seen in both experimental sets. However, the radish plants co-irrigated with PFOS brought about increased movement of ECs from roots to aerial parts, more specifically ATN and CBZ in the soil experimental set, and ATN and TCS in the soilless set. These results support the notion that factors inherent to the physiological characteristics of this root vegetable contributed to ECs’ increased tendency to move from roots to aerial parts. Despite the three ECs efficiently accumulating, the risk to humans from eating the edible parts of these plants grown under soil or soilless conditions was low.
Article
Previous studies have shown that accumulation of perfluoroalkyl acids (PFAAs) in the tissues of aquatic species is highly variable. Movement and migration patterns in these species represent an important consideration when evaluating contaminant accumulation in exposed biota, and may have a large influence on the risk profiles for migratory seafood species. In this study, relationships between PFAA concentrations in muscle and liver tissue, and recent fish migration history (inferred from metals profiles in fish otoliths, otherwise known as otolith chemistry) were evaluated in Sea Mullet (Mugil cephalus). A greater number of PFAAs, and higher concentrations, were found in liver compared to muscle tissue. Perfluorooctane sulfonate (PFOS) was present in highest concentrations in both muscle and liver tissues, and there was strong correlation in concentrations between these two tissues. PFOS was found to decrease and increase alongside recent strontium and barium concentrations (respectively) in the otolith, suggesting higher concentrations of PFAAs in fish recently exposed to comparatively lower salinity environments. This study highlights how otolith chemistry can be employed to examine links between contaminant concentrations in fish, and their recent migration history. This approach shows promise for studying contaminant residues in mobile seafood species within the natural environment.
Article
An analytical method based on liquid chromatography coupled to mass spectrometry was validated to quantify five perfluorinated carboxylic acids (PFCA) namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), and perfluoroundecanoic acid (PFUnA), in wastewater produced in a megacity. Sampling was performed on a monthly basis, obtaining samples from the undergrounded sewerage system and the main open-air canal transporting wastewater out the city. Steady levels of the sum of the target PFCA (ƩPFCA) were determined on both sites through the study: 419.4 ± 24.3 ng L⁻¹ in undergrounded sewage and 591.1 ± 39 ng L⁻¹ in the open-air canal. Short-chain PFCA (PFBA, PFHxA, and PFHpA) were abundant, while concentrations of PFOA and PFUnA remained lower in both sampling sites. The open-air canal was transected in four sampling points, which were sampled throughout the monitoring campaign, finding that furtive discharges of municipal and industrial wastewater increased the levels of short-chain PFCA, while those of PFOA and PFUnA were depleted. Relevant concentrations of PFBA (176.9 ± 3.3 ng L⁻¹), PFHxA (133.4 ± 2.5 ng L⁻¹), PFHpA (116.6 ± 3.9 ng L⁻¹), PFOA (133.1 ± 3.5 ng L⁻¹), and PFUnA (23.5 ± 6.5 ng L⁻¹) were found 60 km downstream, where the wastewater transported by the open-air canal is used in irrigation. A fraction of sewage is treated in a conventional wastewater treatment plant. The concentration of short-chain PFCA increased in effluent, adding extra loads of PFBA, PFHxA, and PFHpA to the environment.
Article
Data on gestational exposure characteristics and transplacental transfer are quite limited for perfluoroalkyl substance (PFAS) isomers, especially those from large-scale comparative studies. To fill this gap, we examined isomers of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS) in matched maternal and cord serum from Mianyang and Hangzhou, which are located in the upper and lower reaches of the Yangtze River, China, respectively. These data were compared with those from our previous study on Wuhan in the middle reach. The average ΣPFAS concentrations increased from upstream to downstream (Mianyang (4.44 ng/mL) < Wuhan (9.88 ng/mL) < Hangzhou (19.72 ng/mL)) and may be related to the per capita consumption expenditures of each city. The ln-transformed PFAS concentrations showed significant differences between Mianyang and Hangzhou after adjusting confounding factors (p < 0.05). The percentages of linear PFOS and PFOA in maternal and cord serum from these cities all exceeded those in electrochemical fluorination products. The isomer profiles of PFASs in maternal and cord serum might be greatly influenced by local production processes of PFASs and residents’ dietary habits. The transplacental transfer efficiencies decreased significantly with increasing concentrations in maternal serum for ΣPFAS, ΣPFOS, ΣPFOA, ΣPFHxS, n-PFOS, iso-PFOS, 4m-PFOS, 1m-PFOS, n-PFOA, n-PFHxS, and br-PFHxS (Spearman rank correlation coefficients (r) = 0.373−0.687, p < 0.01). These findings support an understanding of the regional characteristics in maternal exposure to PFASs along the Yangtze River, isomeric profiles of PFASs in these regions, and the transplacental transfer processes of PFAS isomers.
Article
Contamination of perfluoroalkyl substances (PFASs) in agricultural products have attracted more and more attentions recently. In this review, relationship between PFASs and vegetables is summarized comprehensively. PFASs could transfer to cultivation soils by irrigation water, bio-amended soil, and atmospheric deposition mainly from industrial emissions. Carbon chain length of PFASs, species of vegetables and so on are key factors for PFASs migration and bioaccumulation in soils, plants and vegetables. Studies on food risk assessment of PFOA and PFOS show low consumption risk for most vegetables, however researches on other substances are lacking. In the future, we need to pay more attention on novel pollution pathway in cultivation, traceability research for considerable contamination, dietary exposure levels for different vegetables and more substances, as well as more exact and scientific food risk assessments. Additionally, effective means for PFASs adsorption in soil and removal from soil are also expected.
Article
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Per- and polyfluoroalkyl substances (PFAS) are Synthetic Organic Compounds (SOCs) which are of current concern as they are linked to a myriad of adverse health effects in mammals. They can be found in drinking water, rivers, groundwater, wastewater, household dust, and soils. In this review, the current challenge and status of bioremediation of PFAs in soils was examined. While several technologies to remove PFAS from soil have been developed, including adsorption, filtration, thermal treatment, chemical oxidation/reduction and soil washing, these methods are expensive, impractical for in situ treatment, use high pressures and temperatures, with most resulting in toxic waste. Biodegradation has the potential to form the basis of a cost-effective, large scale in situ remediation strategy for PFAS removal from soils. Both fungal and bacterial strains have been isolated that are capable of degrading PFAS; however, to date, information regarding the mechanisms of degradation of PFAS is limited. Through the application of new technologies in microbial ecology, such as stable isotope probing, metagenomics, transcriptomics, and metabolomics there is the potential to examine and identify the biodegradation of PFAS, a process which will underpin the development of any robust PFAS bioremediation technology.
Article
In recent years, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been recognized as widespread persistent organic pollutants and identified as a great concern to public health. Electron beam (eBeam) technology is a form of ionizing radiation that had been previously successful in mediating the breakdown of PFOA and PFOS. These studies report complete breakdown of PFOA and partial breakdown of PFOS in samples with high pH, nitrate content, alkalinity, and anoxic conditions when exposed to eBeam technology at a dose of 50 kilograys (kGy). In lab-spiked water and sand, the concentrations of PFOA were reduced by 87% and 86% respectively. PFOS was reduced by 16% in lab-spiked water and 28% in lab-spiked sand. In spiked IDW groundwater exposed to 50 kGy, PFOA and PFOS were reduced by 98% and 41% respectively. Groundwater samples were collected from a monitoring well at Randolph AFB in San Antonio, TX, USA. Similarly, PFOA was reduced by 94% and PFOS by 41% in spiked post-UV wastewater effluent collected at the Texas A&M water treatment plant in College Station, TX, USA. Although the aforementioned conditions facilitated the complete breakdown of PFOA, more optimization and higher doses will be needed to achieve the same in PFOS.
Article
Benzotrifluoride (BTF) and its derivatives (BTFs) were found in the groundwater of the Veneto region (Italy) as a result of industrial contamination dating back to the 1970s. In the first survey, BTF and 6 BTFs were identified, out of which 4-chloro-3nitrobenzotrifluoride (3N4CBTF) was the only quantified analyte (concentration up to 1 mg L⁻¹) and was used to trace the contamination plume. A survey carried out in 2008–2009 after the development of more suitable analytical procedures based on GC-MS, allowed to determine 4 new derivatives in addition to BTF and BTFs previously identified, with the most abundant compounds found at concentrations up to 11.9 μg L⁻¹ and 7.2 μg L⁻¹ respectively. A systematic monitoring program for the evaluation of persistence and distribution of fluorinated compounds was carried out in 2013–2018, and new data about the BTF and BTFs occurrence and distribution were gathered. Additional BTFs were identified and high concentrations of individual BTFs were recorded near the contamination source (e.g. 20.3 μg L⁻¹ of 4-chloro-3-nitrobenzotrifluoride in 2017) as well as at large distance (e.g. 22.4 μg L⁻¹ of 3N4CBTF and 12.5 μg L⁻¹ of 4-chlorobenzotrifluoride in 2018). The results of BTFs monitoring campaigns carried out in 2008–2009 and 2017–2018 are compared and related to the historical data to assess the overall occurrence and distribution of BTFs contamination over a time range of ∼40 years. Remarkably, BTFs were still found (2018) at μg L⁻¹ range. Spatial and temporal occurrence of BTF and BTFs in groundwater has been assessed for the first time.
Article
Background Per- and poly-fluorinated alkyl substances (PFAS) are environment-persitent emerging endocrine disrupting chemicals raising health concerns worldwide. Exposure to PFAS has been associated with the imbalance of thyroid hormones. However, available studies addressing the cell mechanism underlying thyroid disrupting feature of legacy PFAS, such as perfluoro-octanoic acid (PFOA), perfluoro-octane-sulfonic acid (PFOS), and the new generation substitutes, such as C6O4, are still lacking. In this study the potential disrupting effect of PFOA, PFOS, and C6O4 on a murine thyroid cell model was assessed.MethodsA rat FRTL-5 cell line was used as the normal thyroid follicular cell model. Cell iodide-uptake, induced by thyroid stimulating hormone (TSH), was used to assess the functional impact of PFAS exposure on cell function. Tetrazolium salt-based cell viability assay and merocyanine 540-based cell staining were used to address the possible involvement of cell toxicity and membrane biophysical properties on altered cell function. The possible direct interaction of PFAS with TSH-receptor (TSH-R) was investigated by computer-based molecular docking and analysis of molecular dynamics. Evaluation of intracellular cAMP levels and gene expression analysis were used to validate the direct impairment of TSH-R-mediated downstream events upon PFAS exposure.ResultsDifferent from PFOS or C6O4, exposure to PFOA at a concentration ≥ 10 ng/mL was associated with significant impairment of the iodide uptake upon TSH stimulation (respectively: basal 100.0 ± 19.0%, CTRL + TSH 188.9 ± 7.8%, PFOA 10 ng/mL + TSH 120.4 ± 20.9%, p= 0.030 vs CTRL + TSH; PFOA 100 ng/mL + TSH 115,6 ± 12,3% p= 0.017 vs CTRL + TSH). No impairment of cell viability or membrane stability was observed. Computational analysis showed a possible direct differential interaction of C6O4, PFOA, and PFOS on a same binding site of the extracellular domain of TSH-R. Finally, exposure to PFOA was associated with a significant reduction of downstream intracellular cAMP levels and both sodium-iodide transporter and thyroperoxidase gene expression upon TSH-R stimulation.Conclusions Our data suggest that legacy and new generation PFAS can differentially influence TSH dependent signaling pathways through the direct interaction with TSH-R.
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Perfluorinated compounds (PFCs) are a class of persistent organic pollutants with widespread distribution in the environment. Since the soil environment has become a significant sink for PFCs, the toxicological assessment about their potential effects on terrestrial organisms is necessary. This review compiles the toxicity researches of regular and emerging PFCs on classical terrestrial biota i.e. microorganisms, earthworms, and plants. In the soil environment, the bioavailability of PFCs much depends on their adsorption in soil, which is affected by soil properties and PFCs structure. By the exploration of bacterial community richness and structure, the gene expression, the influences of PFCs on soil microorganisms were revealed; while the plants and earthworms manifested the PFCs disruption not only through macroscopic indicators, but also from molecular and metabolite responses. Basically, the addition of PFCs would accelerate the production of reactive oxygen species (ROS) in terrestrial organisms, while the excessive ROS could not be eliminated by the defense system causing oxidative damage. Nowadays, the PFCs toxic mechanisms discussed are limited to a single strain, Escherichia coli; thus, the complexity of the soil environment demands further in-depth researches. This review warrants studies focus on more potential quantitative toxicity indicators, more explicit elaboration on toxicity influencing factors, and environmentally relevant concentrations to obtain a more integrated picture of PFCs toxicity on terrestrial biota.
Article
The occurrence and distribution of poly- and perfluoroalkyl substances (PFASs) in water and sediment cores from a surface flow wetland ecosystem (New York State, USA), as well as their relationships with microbial communities were investigated. The total concentrations of PFASs (∑PFASs) in aqueous phase were in the range of 27.6–94.2 ng L⁻¹, while the values in the sediment varied from 2.1 ng g⁻¹ to 6.6 ng g⁻¹. In the aqueous phase, perfluorooctanoic acid (PFOA) (9.4–28.8 ng L⁻¹) was the most predominant compound, followed by perfluorooctane sulfonic acid (PFOS) (5.8–15.4 ng L⁻¹). PFOS was dominant in sediment, with an average concentration of 2.6 ng g⁻¹, followed by PFOA (0.5 ng g⁻¹) and perfluorohexanesulfonate (PFHxS) (0.1 ng g⁻¹). Sediment-water distribution coefficients (log Kd) were in the range 0.7–2.5, and increased with the increase in perfluoroalkyl chain length. Carbon-chain length was a primary factor governing the distribution and behavior of PFASs in the aquatic environment. A positive correlation between the average log KOC and the chain length of perfluoroalkyl (p < 0.01) was observed. Illumina high-throughput sequencing technology was applied to profile the composition of bacterial community in the sediments. At the phylum level, the predominant (> 1.0%) bacteria included Proteobacteria (63.67%), Armatimonadetes (12.98%), Actinobacteria (9.57%), Bacteroidetes (5.08%), and Verrucomicrobia (1.1%). Variations in microbial communities among sampling stations associated with PFAS concentrations were mainly due to the differences in abundances of Candidatus planktophila, Fluviicola, Methylobacillus, Limnohabitans and Flavobacterium. Results of this study would be beneficial to understanding the distribution and bioaccumulation of PFASs in environmental matrix and provide some useful information for controlling PFASs contaminations in wetland ecosystems.
Article
Perfluorooctane sulfonate (PFOS) is the most typical compound as emerging persistent organic pollutants (POPs). It is very significant to monitor PFOS concentration in environmental samples. In this paper, a novel fluorescence probe based on a cationic perylene diimide derivative (PDI-Pyr) toward PFOS detection was designed and synthesized. The sensing properties were investigated systematically by spectroscopic techniques. The detection limit in the method was calculated to be 28 nmol/L. It was found that the formation of PDI-Pyr/PFOS complex through electrostatic and hydrophobic interactions accounted for the mechanism of the fluorescent assay. This method could be further applied in real tap water samples and environmental samples such as soil extract. To the best of our knowledge, this work is the first report of PDI-based fluorescent sensor for PFOS determination.
Article
Improving understanding and characterization of complex fluid systems are crucial tasks of integral product and process design. Of particular interest is the development of enhanced surfactants for industrial and household applications. In this work, a coarse-grained molecular model is developed to study docusate sodium-water-cyclohexane microemulsion systems. Most of the model parameters are taken from a corresponding states treatment of the statistical associating fluid theory-γ-Mie equation of state, overcoming time-consuming simulations. A good agreement is found between model predictions and experimental data, including the phase boundary and reverse micellar aggregation numbers. The effect of water over the morphology of single reverse micelles was studied over the water:surfactant molar ratio range 1 – 14, where a predominant spherical shape was obtained with an average shape anisotropy value of 0.003. The gained molecular insights would be further exploited for the design of more efficient, effective and non-toxic surfactants.
Article
Sixty rainwater samples were collected covering four seasons from July 2020 to April 2021 from the center of Chongqing, a metropolitan city of southwest China, using automatic deposition sampler. The samples were analysed for 17 targeted poly- and per-fluoroalkyl substances (PFASs) by HPLC-MS/MS. The concentration of PFASs ranged from 3.31 ng/L to 196.14 ng/L and dominated by perfluoro-n-octanoic acid (PFOA), perfluoro-n-hexanoic acid (PFHxA), perfluoro-n-butanoic acid (PFBA) and sodium perfluoro-1-octanesulfonate (PFOS). The seasonal variations of dissolved and particulate PFAS were distinct, with the highest level in summer and autumn, respectively. Positive matrix factorization (PMF) and a wet deposition model were performed to apportion the sources and estimate the wet deposition flux of the 17 PFASs, respectively. PMF analysis indicated that, based on yearly average, paper packaging production (37.4%) and aqueous film forming foam (AFFF) usage (29.8%) were the two major sources, followed by textile production (16.7%) and electronic product manufacturing (16.1%). The highest source contributor for PFASs in winter was AFFF usage (47.0%); while in the other three seasons, it was paper packaging production that contributed the most (50.1%, 39.8% and 34.8% respectively). Seasonal average wet deposition flux of PFASs was estimated to be 13.9 ng/m²/day. The dry deposition of PFASs was estimated to account for 15.8% of the total atmospheric deposition flux, suggesting a more important role for wet deposition. The results of this study provide important information for understanding of PFASs occurrence and atmospheric wet deposition in Chongqing, and other urban centers across China.
Article
Recycling vital macronutrients, such as nitrogen, from wastewaters back to fertiliser use is becoming essential to ensure sustainable agricultural practices. Technologies developed for such purposes are typically evaluated for their capacity to recover nutrients; however, the presence of contaminants of emerging concern (CECs) in these waste-derived nutrient products must not be overlooked. In this study, nitrogen was recovered from real anaerobically digested municipal sewage sludge reject water using a novel set-up combining membrane-based electroconcentration (EC) with electrochemical advanced oxidation processes (EAOPs). Simultaneously, the fate of five spiked pharmaceuticals (carbamazepine, ciprofloxacin, diclofenac, erythromycin and metoprolol) as well as ten indigenous perfluoroalkyl substances (PFASs) was investigated. The EC-EAOP system was effective in up-concentrating nitrogen ca. 13 times to a final concentration of 12.7 ± 0.8 g L⁻¹ in the nutrient product. At the same time, no up-concentration was observed for the pharmaceuticals and their concentrations in the recovered concentrated remained at ≤3.4 ± 1.3 µg L⁻¹. The EAOPs were the main transformation mechanism for all the pharmaceuticals at 33–88% efficiency, while diclofenac also notably adsorbed in the system (30 ± 1.4%). Out of the ten studied PFASs, only three were found in the recovered nutrient concentrate, albeit at very limited concentrations of ≤0.024 ± 0.013 µg L⁻¹. The EAOPs were found to degrade longer-chain PFASs into their shorter-chain counterparts. The low contaminant concentrations in the nutrient product pose a reduced risk for soil contamination compared to, e.g., biosolids that are more typically used as fertilisers.
Article
GenX is an alternative to perfluorooctanoic acid (PFOA) and was included in the accession list of Substances of Very High Concern in 2019. Gestational GenX exposure induces maternal hepatotoxicity in animals. However, the mechanisms of GenX toxicity have not been explored. In the present study, pregnant Balb/c mice were administered with PFOA (1 mg/kg BW/day), GenX (2 mg/kg BW/day), or Milli-Q water by gavage during gestation. Similar hepatic pathological changes, including enlargement of hepatocytes, cytoplasm loss, nucleus migration, inflammatory cell infiltration, and reduction of glycogen storage, were observed in PFOA and GenX groups. Increased expression levels of indicators of the TLR4 pathway indicated activation of inflammation in the liver of maternal mice after exposure to PFOA or GenX, consistent with the pathological changes. Overexpression of cleaved PARP-1, cleaved caspase 3, Bax and decreased Bcl-2 proteins indicated activation of apoptosis, whereas overexpression of ULK-1, p62, beclin-1, LC3-II proteins and downregulation of p-mTOR implied that PFOA and GenX exposure initiated autophagy. Decreased secretion of mucus, reduced expression levels of tight junction proteins, and higher serum levels of lipopolysaccharide indicated disruption of the intestinal barrier. Translocation of lipopolysaccharide may be recognized by TLR4, thus triggering inflammatory pathway in the maternal liver. In summary, gestational exposure to PFOA or GenX induced maternal hepatic alterations through the gut-liver axis.
Article
Due to their relatively large production and few restrictions on uses, novel substitutes for historically used per and poly-fluoroalkyl substances (PFAS) are being used and accumulating in the environment. However, due to a lack of information on their toxicological properties their hazards and risks are hard to estimate. Before fertilization, oocytes of two salmonid species, Arctic Char (Salvelinus alpinus) and Rainbow Trout (Oncorhynchus mykiss), were exposed to three PFAS substances used as substitutes for traditional PFAS, PFBA, PFBS or GenX or two archetypical, historically used, longer-chain PFAS, PFOA and PFOS. Exposed oocytes were subsequently fertilized, incubated and were sampled during several developmental stages, until swim-up. All five PFAS were accumulated into egg yolks with similar absorption rates, and their concentrations in egg yolks were less than respective concentrations in/on egg chorions. Rapid elimination of the five PFAS was observed during the first 3 days after fertilization. Thereafter, amounts of PFOS and PFOA were stable until swim-up, while PFBA, PFBS and GenX were further eliminated during development from one month after the fertilization to swim-up. In these two salmonid species, PFBA, PFBS and GenX were eliminated faster than were PFOS or PFOA.
Article
Nanoplastics (NPs, <1000 nm) may adsorb organic pollutants in the aquatic environment, thereby, influencing their bioavailability to organisms. This study aims to investigate the individual and combined toxicity of perfluorooctane sulfonate (PFOS) and virgin yellow-green fluorescent polystyrene NPs (200 nm) at sub-lethal doses on the marine mussel Perna viridis. Our results demonstrated that both PFOS single and PFOS-NP co-exposure at 1000 μg/L significantly increased PFOS distribution in the gills, gonads, and visceral mass (p < 0.05), compared to the control. Further, PFOS single and PFOS-NP co-exposures at 100 and 1000 μg/L significantly increased the reactive oxygen species (ROS) levels in mussel tissues that consequently altered the responses of antioxidant entities including MDA, CAT, SOD, GR, and GST. The transcriptional profiling of oxidative stress-related genes (cyp4, hsp22, hsp60, gst-omega, and gst-pi), showed significantly downregulated expressions at the lowest level of co-exposure (PFOS 10 μg/L) in all tissues, especially in gills, compared to the control group. Overall, the enhanced integrated biomarker response (EIBR) revealed PFOS-NP co-exposure at 1000 μg/L, as the most stressful circumstance to induce mixture toxicity, at which more structural damage to the gills and gonads were observed than single PFOS/NPs exposure. In summary, the co-exposure significantly enhanced the PFOS bioaccumulation and ROS levels in mussel tissues, resulting in altered antioxidant and genetic responses, suggesting that NPs could affect the distribution of PFOS between P. viridis and seawater. Hence, further studies should be conducted to unveil the interactive toxic effects of NPs and PFOS on marine mussels.
Article
Per- and polyfluoroalkyl substances (PFAS) are contaminants of global concern due to their persistence and associated negative health effects. Considerable attention has been given to monitoring PFAS in the aquatic environment, however, few investigations have done so using freshwater benthic macroinvertebrates (BMIs). As these bottom-dwelling animals are known to bioconcentrate exogenous pollutants to a high degree, studying their PFAS levels may provide a more integrated view of PFAS contamination in the aquatic environment. In this study, BMIs, sediment, and surface water were collected from two streams in the Hudson River Watershed (one historically-impacted by PFAS) and analyzed for 44 PFAS using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Orbitrap high-resolution mass spectrometry (HRMS) was used to confirm the identities of quantitated analytes. Across all matrices, 17 analytes were detected with PFOA dominating in surface water and PFOS in sediment/BMIs. PFOS bioaccumulation factors (BAFs) were approximately one order of magnitude higher than those of PFOA and ranged from 857–5151 L kg⁻¹ across different BMI taxa. While PFAS concentrations in surface water and sediment were not excessively high, elevated levels were still measured in most BMI taxa. This observation suggests that the extent of PFAS contamination in a local system may be severely underestimated if only surface water and sediment are used for monitoring. Moreover, these findings have relevance for human exposure assessment considering BMIs are the primary food source of many fish.
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Even though the endocrine-disrupting potential of perfluorooctanoic acid (PFOA) is well known, the mechanisms underlying its cellular and epigenetic toxicity at the critical stage of hypothalamic development are poorly understood. This is why we studied its effects on the embryonic mouse hypothalamic cell line N46 (mHypoE-N46) with a hope to shed more light on the mechanisms through which PFOA causes embryonic hypothalamic cell damage. To do that, we studied cell viability, global DNA methylation, and gene expression in cells exposed to PFOA. As the PFOA dose increased, cell viability decreased, while global DNA methylation increased. PFOA also significantly altered the expression of genes related to the apoptosis and cell cycle, neurotrophic genes, and the Tet, Dnmt, and Mecp2 genes. Our findings suggest that exposure to PFOA affects cell survival through the reprogramming of embryonic hypothalamic DNA methylation patterns and altering cell homeostasis genes. DNA methylation and changes in the Mecp2 gene expression induced by PFOA also imply wider ramifications, as they alter genes of other major mechanisms of the embryonic hypothalamus. Our study may therefore serve as a good starting point for further research into the mechanisms of PFOA effect of hypothalamic development.
Article
Perfluorooctane sulfonate (PFOS) is a widely used artificial surfactant with potential toxicity to humans and animals. However, little is known about the impact of PFOS on the female germ cell development. Here, we report that PFOS exposure weakens oocyte quality by disturbing oocyte meiotic competency and fertilization ability. Specifically, PFOS exposure impaired cytoskeleton assembly including spindle organization and actin polymerization to cause the oocyte maturation arrest. In addition, PFOS exposure also impaired the mitochondrial dynamics and function, resulting in the increased levels of reactive oxygen species (ROS) and DNA damage as well as generation of apoptosis. Lastly, PFOS exposure compromised the distribution of cortical granules (CGs) and their component ovastacin, leading to the failure of sperm binding and fertilization. Altogether, our study illustrates that oxidative stress-induced apoptosis is a major cause for the deteriorated quality of porcine oocytes exposed to PFOS.
Article
Water diversion is increasingly utilized for water supply, flood control, irrigation, and water quality improvement in many water bodies globally. Our findings indicate that micropollutants such as perfluoroalkyl acids (PFAAs) can be transported via dual-source water diversion projects during water diversion and flood discharge, which may negatively impact both receiving water bodies. However, the sources, spatiotemporal variations, and fluxes of PFAAs under water diversion projects remain unclear. Here we report patterns of 18 PFAA compounds in the surface water at 14 sites of a dual-source water diversion project (Wangyu River) connecting the Yangtze River and Taihu Lake in China. We found multiple contamination hotspots with PFHxA and PFOA dominantly originating from industrial and domestic sources during water diversion from the Yangtze River to Taihu Lake. During the severe flooding in summer 2020, PFAA concentrations ranged from 82.0 to 114.0 ng L-1, while the concentrations and relative contributions of individual perfluoroalkane sulfonic acids (PFSAs) increased along the mainstream due to the tributaries' contribution and high contamination level in the lake. Based on the spatiotemporal patterns of PFAA pollution, the flux of total PFAAs including both dissolved-phase and SS-phase into Taihu Lake was estimated as 26.6 kg in January 2020 as a reference value for water diversion. To our knowledge, this is the first report to describe the sources, occurrences, and transport of PFAAs in a dual-source water diversion project during water diversion and flooding. The results provide a novel perspective regarding the ecological safety of dual-source water diversion projects.
Article
The occurrence, spatial distribution, potential sources, and risk assessment of 14 perfluoroalkyl acids (PFAAs), including 11 perfluoroalkyl carboxylic acids and 3 perfluoroalkyl sulfonates acids, were investigated in 21 drinking water sources from the lower Yangtze River in November 2019. The total PFAAs (∑PFAAs) concentrations ranged from 39.3 to 220.3 ng/L, and perfluorooctanoic acid and perfluorooctanesulfonate were predominant with average concentrations of 19.4 and 15.4 ng/L, respectively. The higher ∑PFAAs concentrations in the southern shore and downstream could be attributed to industrial development and surface runoff/tide currents, respectively. Principal component analysis-multiple linear regression revealed that the primary sources of PFAAs were fluororesin coatings/metal plating, surface runoff/textile, effluent discharge/food packaging, and leather/fabrics. Human intake risks of PFAAs were assessed by target hazard quotient (THQ), which showed that human health risks of PFAAs decreased with increasing age, excluding 13–17 years age group. Moreover, the total exposure risks of PFOA/PFOS in all sampling sites to people aged over 18 years calculated based on contribution from drinking water were noted to be at safe level. The results obtained were helpful for improving our understanding of human health risks of PFAAs, and expanding our knowledge on PFAAs in drinking water.
Article
Aqueous Film Forming Foams (AFFFs) are used in firefighting and are sources of per‐ and poly‐fluoroalkyl substances (PFAS) to the environment through surface runoff and groundwater contamination at defense and transportation sites. Little is known regarding the toxicity and bioaccumulation of newer AFFF formulations containing novel PFAS. To mimic maternal transfer of PFAS, pre‐fertilization rainbow trout eggs were exposed to three PFAS using novel methodologies. Batches of unfertilized oocytes were exposed for three hours to 0, 0.01, 0.1, 1 or 10 µg/mL separately to perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA) or perfluorooctanesulfonic acid (PFOS) in either coelomic fluid or Cortland’s solution. After exposure, the gametes were fertilized and rinsed with dechlorinated water. Egg yolk was aspirated from a subset of fertilized eggs for PFAS quantification. Each PFAS was detected in yolks of eggs exposed to the respective PFAS and yolk concentrations were directly proportional to concentrations in aqueous media to which they were exposed. Exposure in coelomic fluid or Cortland’s solution resulted in similar concentrations of PFAS in egg yolks. Ratios of PFAS concentrations in oocytes to concentrations in exposure media (OFR) were less than 0.99 when exposed from 0.01 to 10 µg/mL while less than 0.45 when exposed from 0.1 to 10 µg/mL for both media and all three PFAS, demonstrating that the water solubility of the chemicals was relatively great. Pre‐fertilization exposure of eggs effectively introduced PFAS into unfertilized egg yolk. This method provided a means of mimicking maternal transfer to evaluate toxicity to developing embryos from an early stage. This method is more rapid and efficient than injection of individual fertilized eggs and avoids trauma from inserting needles into eggs. This article is protected by copyright. All rights reserved.
Article
NMR spectroscopy is arguably the most powerful tool for the study of molecular structures and interactions, and is increasingly being applied to environmental research, such as the study of wastewater. With over 97% of the planet’s water being saltwater, and two thirds of freshwater being frozen in the ice caps and glaciers, there is a significant need to maintain and reuse the remaining 1%, which is a precious resource, critical to the sustainability of most life on Earth. Sanitation and reutilization of wastewater is an important method of water conservation, especially in arid regions, making the understanding of wastewater itself, and of its treatment processes, a highly relevant area of environmental research. Here, the benefits, challenges and subtleties of using NMR spectroscopy for the analysis of wastewater are considered. First, the techniques available to overcome the specific challenges arising from the nature of wastewater (which is a complex and dilute matrix), including an examination of sample preparation and NMR techniques (such as solvent suppression), in both the solid and solution states, are discussed. Then the arsenal of available NMR techniques for both structure elucidation (e.g., heteronuclear, multidimensional NMR, homonuclear scalar coupling-based experiments) and the study of intermolecular interactions (e.g., diffusion, nuclear Overhauser and saturation transfer-based techniques) in wastewater are examined. Examples of wastewater NMR studies from the literature are reviewed and potential areas for future research are identified. Organized by nucleus, this review includes the common heteronuclei (¹³C, ¹⁵N, ¹⁹F, ³¹P, ²⁹Si) as well as other environmentally relevant nuclei and metals such as ²⁷Al, ⁵¹V, ²⁰⁷Pb and ¹¹³Cd, among others. Further, the potential of additional NMR methods such as comprehensive multiphase NMR, NMR microscopy and hyphenated techniques (for example, LC-SPE-NMR-MS) for advancing the current understanding of wastewater are discussed. In addition, a case study that combines natural abundance (i.e. non-concentrated), targeted and non-targeted NMR to characterize wastewater, along with in vivo based NMR to understand its toxicity, is included. The study demonstrates that, when applied comprehensively, NMR can provide unique insights into not just the structure, but also potential impacts, of wastewater and wastewater treatment processes. Finally, low-field NMR, which holds considerable future potential for on-site wastewater monitoring, is briefly discussed. In summary, NMR spectroscopy is one of the most versatile tools in modern science, with abilities to study all phases (gases, liquids, gels and solids), chemical structures, interactions, interfaces, toxicity and much more. The authors hope this review will inspire more scientists to embrace NMR, given its huge potential for both wastewater analysis in particular and environmental research in general.
Article
Probiotic supplementation is effective to modulate the metabolic disorders caused by perfluorobutanesulfonate (PFBS). However, the underlying mechanisms remain unclear. To this end, the present study exposed adult zebrafish to PFBS (0 and 10 μg/L), probiotics, or their binary combinations for 40 days. After the exposure, the nutritional stores, intestinal organization, and metabolic activities along the gut-liver axis were investigated. The results showed that PFBS exposure decreased the nutrient reserves significantly, especially the lipid content, which was alleviated by the probiotic administration. Intestinal mucus secretion was promoted remarkably in the presence of the probiotic, which enhanced epithelial protection against PFBS damage. Metagenomic analysis showed that PFBS alone induced gut microbial dysbiosis, which was efficiently antagonized by the probiotic bacteria. Intestinal metabolomic profiling revealed that ferroptosis occurred because of the unrestricted lipid peroxidation following PFBS exposure. However, probiotic administration prevented the ferroptotic symptoms induced by PFBS, further highlighting the beneficial effects of the probiotic on the host. In PFBS-exposed livers, high levels of bile acid metabolites (e.g., taurochenodeoxycholic acid) accumulated, implying the induction of cholestasis. Notably, probiotic addition recovered the metabolomic homeostasis under PFBS stress, probably resulting from the activation of detoxification pathways based on the pentose and glucuronate interconversion. Overall, the present study provides systematic evidence of the antagonistic interaction between PFBS and the probiotic regarding the metabolic activities along the microbe, gut and liver axis, highlighting the application values of probiotic recipe in aquaculture industry and ecological reservation.
Article
Perfluoroalkyl substances (PFASs) are a family of chemicals widely distributed in daily use consumer products. Most of these products become municipal solid wastes (MSWs) after they have been used. In the present study, we examined different types of PFASs in leachate, fly ash and bottom ash produced from three MSW incineration plants in southern China. High PFAS levels were found in leachate (mean concentration 215 ng/mL, range 21.4–682 ng/mL) from the incineration plants, which indicated large amounts of PFASs in the wastes leached out. The average quantities of PFASs annually discharged from the leachates of the three plants were estimated to be approximately 384 kg (Plant A), 47.3 kg (Plant B), and 2.82 kg (Plant C). Relatively lower levels of PFASs in fly ash (mean 16.4 ng/g, range 1.46–87.6 ng/g) and bottom ash (mean 14.6 ng/g, range 3.11–77.4 ng/g) indicated that high-temperature incineration destroyed most of the PFASs. The wide array of PFASs concentrations in all three matrices illustrated that some PFASs-containing industrial wastes were still entered into local MSW. In general, short chain PFASs, including perfluorobutyric acid (PFBA) and perfluorobutane sulfonate (PFBS), were the primary PFASs in leachate samples. In addition, PFOS was the predominant PFASs in fly ash samples. The results showed that leachate, fly ash, and bottom ash from MSW incineration plants are important vectors of PFASs.
Article
Effects of perfluorooctane sulfonate (PFOS) and a legacy aqueous film forming foam containing 91% PFOS (AFFF PFOS) on reproduction, chick survivability and growth of Japanese quail (Coturnix japonica) were determined. Day‐old Japanese quail were administered PFOS or AFFF PFOS at 6 dietary concentrations ranging from 0 to 21 mg kg‐1 feed for a total of 20 wk. At 4 wk of age, 16 male/female pairs per treatment were assigned to cages and egg laying was induced by 10 wk of age. Eggs were collected daily, set weekly and incubated for 18 d for the following 10 wk. Hatchlings were fed uncontaminated feed for 2 wk, euthanized to collect blood and liver. After 10 wk of egg collection, adults were euthanized to collect blood, liver, and kidneys. Significantly increased myofiber numbers in the liver and glomerular sclerosis in the kidneys of adults indicated damage at greater doses. PFOS or AFFF PFOS did not significantly affect egg production, but hatchability was decreased at the greatest PFOS dose. The no observed adverse effect levels for chick survivability, considered the critical effect, were 4.1 mg PFOS kg feed‐1 (0.55 mg kg body weight‐1 d‐1) and 5.0 mg AFFF PFOS kg feed‐1 (0.66 mg kg body weight‐1 d‐1) resulting in calculated average toxicity reference values of 0.25 mg kg feed‐1 and 0.034 mg kg bw‐1 d‐1. This article is protected by copyright. All rights reserved.
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In this chapter, we report on the state of PFAS in a major South Indian River Periyar, for the first time. These substances are classified as a pollutant in many countries. Ingestion of these substances is known to cause adverse effects on the humans. Periyar is the largest west-flowing river in southern India (5398 km2 area covering 300 km in length). River water samples were collected from 16 stations (including the source, mouth, estuaries and main tributaries) in May 2013. HPLC MS/MS was used to measure the concentration of PFAS. The recovery of 13C labeled standards ranged between 60 and 100%. Perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) were found in all the 16 sampling stations. The PFBA concentration varied between 58 and 2174 ng/L. PFOA concentration varied between 22 and 1503 ng/L, and PFNA varied between 20 and 705 ng/L. Out of the six major PFAS analyzed, three perfluorosulfonates (PFSA) and three perfluoroalkyl carboxylic acids (PFCA) were detected. The highest concentration of PFAS was found near the Periyar estuary (12,958 ng/L).
Article
Perfluoroalkyl substances (PFAS) are surface‐active agents used in diverse industrial and commercial applications. PFAS contaminate both freshwater and marine ecosystems, are highly persistent and accumulate through trophic transfer. Seabirds are exposed to environmental contaminants due of their high trophic position in food webs and relatively long lifespan. We measured levels of ten perfluoroalkyl acids (PFAAs) in egg yolks of yellow‐legged gulls (Larus michahellis) breeding in the northern Adriatic sea (NE Italy). We examined PFAAs variation within clutches (between eggs of different laying order) and among clutches. Perfluorooctane sulfonate (PFOS) was the most abundant yolk PFAA (mean = 42.0 ng/g wet weight), followed by perfluorooctanoic acid (PFOA; 3.8 ng/g ww) and perfluorododecanoic acid (PFDoDa; 2.8 ng/g ww). ƩPFAAs averaged57.4 ng/g ww, ranging between 26.5 and 115.0 ng/g ww. PFAA levels varied substantially among clutches (0.29 ‐ 0.79 of total variation), whereas the effects of laying order were considerably weaker (0.01 ‐ 0.13). Egg laying order effects were detected for ƩPFAAs, PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA) and PFDoDa, whereby the last‐laid eggs exhibited lower PFAAs concentrations than early‐laid eggs. Our results indicate that seagulls from the northern Adriatic basin deposit measurable amounts of PFAAs in their eggs. The large among‐clutches differences in PFAAs suggest that exposure of yellow‐legged gull females to these compounds is highly variable. This article is protected by copyright. All rights reserved.
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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.
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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.
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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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