Perfluorooctane Sulfonates Research Articles

Adolescent F-53B exposure induces ovarian toxicity in rats: Autophagy-apoptosis interplay

As a substitute for perfluorooctane sulfonates, F-53B has permeated into the environment and can reach the human body through the food chain. Adolescent individuals are in a critical stage of development and may be more sensitive to the impacts of F-53B. In the present study, we modeled the exposure of adolescent female rats by allowing them free access to F-53B at concentrations of 0 mg/L, 0.125 mg/L, and 6.25 mg/L in drinking water, aiming to simulate the exposure in the adolescent population. Using the ovary as the focal point, we investigated the impact of developmental exposure to F-53B on female reproduction. The results indicated that F-53B induced reproductive toxicity in adolescent female rats, including ovarian lesions, follicular dysplasia and hormonal disorders. In-depth investigations revealed that F-53B induced ovarian oxidative stress, triggering autophagy within the ovaries, and the autophagy exhibited the interplay with apoptosis in turn, collectively leading to significant ovarian toxicity. Our findings provided deeper insights into the roles of the autophagy-apoptosis interplay in ovarian toxicity, and offered a new perspective on the developmental toxicity inflicted by adolescent F-53B exposure.

Distribution and bioaccumulation of per- and polyfluoroalkyl substances (PFASs) in the Kuroshio Extension region of Northwest Pacific Ocean

Per- and polyfluoroalkyl substances (PFASs) are prevalently present in oceans, posing potential health risks to organisms and humans. However, information of PFAS distribution in remote open oceans is limited. In the Kuroshio Extension region of Northwest Pacific Ocean (6 stations), samples of 84 seawater (0–5800 m), 9 sediments, and 9 organisms were taken, and 25, 10, and 15 out of 29 PFASs were identified, respectively, with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonates (PFOS) as the most dominant PFASs. In seawater, ΣPFASs concentration decreased from the Kuroshio region (4.47 ng/L) to the Oyashio region (3.15 ng/L), and decreased with increasing seawater depth under the function of biological and physical pumps. Additionally, 12 precursors and emerging PFASs, including perfluorooctane sulfonamide (FOSA, 0.20 ng/L), were detected. In sediment, PFASs (5.92–12.97 pg/g) were identified at depths exceeding 5000 m, including 3 precursors (e.g., FOSA, 0.82 pg/g). ΣPFASs contents were 27.12, 31.47 and 36.97 ng/g (dry weight) in brown algae (Phaeophyceae), barnacles (Balanus), and lanternfish (Myctophiformes), respectively, in which two precursors (e.g., FOSA, 0.09–0.12 ng/g) were also identified. A correlation with the trophic position was found for PFOA bioaccumulation. These findings provide useful information on PFAS distribution in the global open ocean environments.

Maternal PFOS exposure in mice induces hepatic lipid accumulation and inflammation in adult female offspring: Involvement of microbiome-gut-liver axis and autophagy

Perfluorooctane sulfonates (PFOS) are the persistent organic pollutants. In the present study, 0, 0.3, or 3-mg/kg PFOS were administered to pregnant mice from GD 11 to GD 18. The histopathology of liver and intestine, serum and hepatic lipid levels, lipid metabolism related genes, and gut microbiota were examined in adult female offspring. The results suggested that maternal PFOS exposure increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and induced F4/80+ macrophage infiltration in adult female offspring, in addition to the elevation of TNF-α and IL-1β mRNA levels in low-dose and high-dose groups, respectively. Furthermore, maternal exposure to PFOS increased serum triglyceride (TG) and hepatic total cholesterol (TC) levels, which was associated with the alteration of the process of fatty acid transport and β-oxidation, TG synthesis and transport, cholesterol synthesis and excretion in the liver. The AMPK/mTOR/autophagy signaling was also inhibited in the liver of adult female offspring. Moreover, changes in gut microbiota were also related to lipid metabolism, especially for the Desulfovibrio, Ligilactobacillus, Enterorhabdus, HT002 and Peptococcaceae_unclassified. Additionally, maternal exposure to PFOS decreased mRNA expressions of the tight junction protein and AB+ goblet cells in the colon, while increasing the overproduction of lipopolysaccharides (LPS) and F4/80+ macrophage infiltration. Collectively, maternal PFOS exposure induced liver lipid accumulation and inflammation, which strongly correlated with the disruption of the gut-liver axis and autophagy in adult female offspring, highlighting the persistent adverse effects in offspring exposed to PFOS.

Analysis on the Substitution of Perfluoro-Octane Sulphonates in Foam-Based Extinguishing Agents in China

In this comprehensive study, we examined an extensive array of 1396 production certifications, which encompassed 136 foam-based extinguishing agent manufacturers in China. Our investigation focused on the production, application, and composition of various foam-based extinguishing agents utilized in recent years. Notably, a significant proportion of the domestic market, i.e., 64.1% of the total, consisted of fluorocarbon surfactants devoid of perfluorooctane sulfonates (PFOS). These manufacturers predominantly operated in the economically thriving eastern coastal region of China. Our research delved into the correlation between diverse parameters of foam-based extinguishing agents and their performance indices. It was observed that foam-based extinguishing agents with resistance to seawater exhibited superior performance to conventional agents in cold environments. Additionally, we synthesized the findings of PFOS-free products, which serve as promising alternatives to foam-based extinguishing agents in China. This study furnishes statistical evidence and establishes a theoretical foundation to facilitate future control measures for PFOS foam-based extinguishing agents, while promoting nationwide research and development of alternative solutions.

Objective Review

Leather industry uses a great number of processing chemicals to make leather from animal hides. The toxicity, health and environmental impacts of many of these chemicals have been established leading to significant regulatory certifications and programs helping in trade and policy making. The focus of this review are the hazardous chemicals and auxiliaries relevant to leather industry, their categories, possible origins, analysis and toxicity with respect to humans and the environment and the regulatory mechanisms suggested for them through manufacturing restricted substance list (MRSL) 2.0.** Informative guidelines are provided about the most probable leather processing stage for the origin of these chemicals. Some alternative technologies, chemicals and ideas gaining popularity are also suggested as probable remedies. Recommended test methods are stated for the adequate monitoring of the hazardous chemicals. The nature and severity of chemical toxicity and corresponding limits set for their allowed use in formulations are graphically expressed for clarity and ease of understanding. The maximum number of compounds / isomers belong to classes comprising chlorinated paraffins, perfluorooctanoic acids (PFOA), perfluorooctanesulfonates (PFOS) and banned aromatic amines. Similarly, most of the restricted chemicals are used during the finishing stage and may be considered for eco-friendly alternatives. Likewise, the analytical equipment covering most testing requirements is GC-MS among other hyphenated techniques. Additionally, most critical chemicals from toxicity point of view are arsenic, cadmium and chromium (VI), whereas navy blue colorants and chlorinated aromatic compounds may be considered as less toxic among the restricted chemicals under the current scope. Surprisingly, the latest UV absorbents and polymeric fatliquors are comparatively non-toxic. Similarly, the most relaxed formulation limits are given for UV absorbers and 2-methoxypropylacetate whereas strict limits have been set for PFOA, PFOS, mercury, triclosan permethrin, sensitizing dyes etc. in MRSL 2.0.

Boosting degradation and defluorination efficiencies of PFBS in a vacuum-ultraviolet/S(Ⅳ) process with iodide involvement

Perfluorobutane sulfonate (PFBS) is considered to be a promising alternative of perfluorooctane sulfonates (PFOS), while it is also hazardous. The UV/S (Ⅳ) system has been confirmed to be effective for PFOS removal from water, while it is inefficient for PFBS decomposition. A hybrid vacuum-ultraviolet (VUV)/S (Ⅳ)/KI process was investigated for the degradation of PFBS in aqueous solution. With KI involvement, the degradation rate of PFBS was boosted from 1.8802 μg h−1 up to 3.5818 μg h−1 in the VUV/S (Ⅳ) process. Alkaline conditions significantly increased the degradation efficiency of PFBS, which can be explained that S (Ⅳ) was dominated by SO32− rather than HSO3− and H2SO3 in alkaline conditions. Cl−, HCO3−, NO3−, NO2−, and HA would inhibit the performance of the VUV/S (Ⅳ)/KI process via various reactions. In addition, the toxicity of PFBS was significantly reduced by the VUV/S (Ⅳ)/KI process. Even in actual waters, the VUV/S (Ⅳ)/KI process also presented a satisfying performance in the degradation of PFBS.

Study on the effect of nanoparticles combined with silicone surfactant and cationic surfactant on foam and fire extinguishing performance.

Aqueous film-forming foam (AFFF) in firefighting foam can effectively extinguish oil fire. However, AFFF will be phased out due to the presence of persistent organic pollutants such as perfluorooctane sulfonates. It is necessary to explore environment-friendly foam extinguishing agent. Silicone surfactant is a kind of environmentally friendly surfactants with high surface activity, which can be used as a substitute for fluorocarbon surfactant. In this study, silicone surfactant and cationic surfactant were combined to adsorb nanosilica particles to form a multiphase system. The foaming property and foam stability of the multiphase system were tested by stirring method. The foam suppression effect on fuel vapor, fire extinguishing, and burn-back performance was tested by self-designed foam suppression device and foam generating device of porous glass with recyclable liquid supply. The experimental results show that foam stability is enhanced and the foaming property is slightly decreased after the addition of nanoparticles. When the component of three-phase foam reaches the optimum, its suppression effect on fuel vapor is better than that of two-phase foam. The results of fire extinguishing and burn-back performance test showed that the fire extinguishing effect of three-phase foam was slightly worse than that of AFFF, but it has extremely strong burn-back performance.

Carbon-dot-modified polyacrylonitrile fiber as recyclable adsorbent for removing anionic, cationic, and zwitterionic perfluorooctane sulfonates from water

There are few adsorbents that can efficiently adsorb perfluorooctane sulfonate (PFOS) with differently polarized head-groups. In the present study, carbon dot (CD)-modified polyacrylonitrile fiber (PAN-g-CD) was found to be a good adsorbent for removing PFOS and its derivatives with zwitterionic or cationic head-groups from neutral water. The maximum adsorption capacities at 25 °C were found to be 1.28, 1.75, 1.87, and 2.11 mmol/g for PFOS, cationic PFOS, betaine-type PFOS, and PFOS with an amine oxide head-group, respectively. Adsorption kinetic models indicated that the surface of PAN-g-CD is energetically heterogeneous and that chemisorption occurs during the adsorption of PFOS and its derivatives. The Sips and Hill isotherm adsorption models were found to be most appropriate, and they indicated that PFOS derivatives were more preferentially adsorbed than PFOS by PAN-g-CD. The high-efficiency and wide substrate range of PAN-g-CD adsorption may be ascribed to its zwitterionic nature and its hydrophobic CDs. Moreover, PAN-g-CD can be regenerated and reused up to four times without pronounced loss of adsorption capacity.

Study on Environmental Regulation of Aqueous Film Forming Foam and Use of C4-Based Eco-Friendly Aqueous Film Forming Foam

The C8-based aqueous film forming foam (AFFF) was developed by 3M in 1960, initially for military purposes, and was then used in all U.S. Navy vessels until the late 1960s. The U.S. Department of Defense used the AFFF for fuel fire suppression in all military facilities in the 1970s. The AFFF was classified as a special fire extinguishing chemical used for an airplane hangar or an aircraft carrier. Despite its strong fire extinguishing capacity, the AFFF is not commonly used by civilians, mainly due to the cost factor and environmental issues. In particular, the main organic chemical component of the AFFF is resistant to degradation; it tends to persist in the ecological system and in the human body, consequently having grievous effects. The paper describes the causes and measures of the AFFF use regulations by the Stockholm Convention concerning persistent organic chemicals. The manuscript also introduces the C4-based eco-friendly AFFF, a fire extinguishing chemical developed in China, as a part of the measure and addresses the meaning of “C4-Based.” Moreover, the study verifies that the representative regulation targets for perfluorooctane sulfonates (PFOS) and perfluorooctanoic acid (PFOA) are not detected in the C4-based eco-friendly AFFF fire extinguishing chemical, as revealed by a test on “the method for analyzing PFOS/PFOA” in the chemical product based on the National Standard Test KS M 9722:2017. Accordingly, various fire extinguishers using the C4-based eco-friendly AFFF with strong and extensive fire extinguishing capacity are proposed, and the other use methods.

Determinants of serum half-lives for linear and branched perfluoroalkyl substances after long-term high exposure—A study in Ronneby, Sweden

BackgroundPer- and polyfluoroalkyl substances (PFAS) are persistent substances with surfactant and repellent properties. Municipal drinking water contaminated with PFAS had been distributed for decades to one third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from December 16, 2013. AimsThe purpose was to estimate serum half-lives and their determinants in the study population for different PFAS. MethodsUp to ten blood samples were collected between 2014 and 2018 from 114 participants (age 4–84 years at entry, 53% female). 19 PFAS were analysed. Linear mixed models were used to estimate the half-lives. ResultsEight PFAS were increased in Ronneby: perfluorooctanoic acid (PFOA), perfluoropentane sulfonate (PFPeS), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS), linear perfluorooctane sulfonate (L-PFOS) and three branched perfluorooctane sulfonates (1 m-PFOS, 3/4/5m-PFOS and 2/6m-PFOS). The mean estimated half-lives (in years) were 0.94 (95 %CI 0.86–1.02) for PFPeS, 2.47 (2.27–2.7) for PFOA, 2.67 (2.51–2.85) for 2/6m-PFOS, 2.73 (2.55–2.92) for L-PFOS, 3.43 (3.19–3.71) for 3/4/5m-PFOS, 4.52 (4.14–4.99) for PFHxS, 4.55 (4.14–5.06) for PFHpS, and 5.01 (4.56–5.55) for 1 m-PFOS.The most important determinants of a shorter half-life were young age, and better kidney function measured by estimated glomerular filtration rate and ratio of paired urine and serum PFAS levels, followed by female sex during their fertile period aged 15–50. Markers of gut inflammation and reduced permeability i.e. zonulin and calprotectin were also possibly associated with shorter half-life. The results also suggested a time-dependent PFAS elimination process, with more rapid elimination in the first year after the end of exposure. ConclusionThe half-life estimates are in line with past estimates for some PFAS such as PFOA, and the novel results for different PFOS isomers. These results provide observational support for elimination routes – renal, fecal and maternal.

Perfluorooctane sulfonates induces neurobehavioral changes and increases dopamine neurotransmitter levels in zebrafish larvae

It has been reported that exposure to perfluorooctane sulfonates (PFOS) causes behavioral abnormalities in zebrafish larvae, but the possible mechanisms underlying these changes remain unexplored. In this study, zebrafish embryos (2 h postfertilization, 2-hpf) were exposed to PFOS at different concentrations (0, 0.032, 0.32 and 3.2 mg/L) for 120 h. Developmental endpoints and the locomotion behavior of larvae were evaluated. Reactive oxygen species (ROS) levels, dopamine contents, several genes and proteins related to neurodevelopment and dopamine signaling were examined. Our results indicate that increased ROS levels in the zebrafish larvae heads may be causally associated with neurodevelopment damage. Meanwhile, brain-derived neurotrophic factor (BDNF) and alpha1-Tubulin (α1-Tubulin) protein contents were significantly increased, which may be a compensatory mechanism for the impaired central nervous system. PFOS-induced locomotor hyperactivity was observed in the first light phase and dark phase at the 0.32 and 3.2 mg/L of PFOS. Upregulation of dopamine-related genes tyrosine hydroxylase (th) and dopamine transporter (dat) associated with increased dopamine contents in the 3.2 mg/L of PFOS. In addition, protein expression of TH and DAT were noted at the 0.32 and 3.2 mg/L of PFOS concentrations. Our results suggested that PFOS induces neurobehavioral changes in zebrafish larvae, possibly by perturbing a dopamine signaling pathway. In addition, PFOS induced development damage, such as increased malformation rate and shorter body length.

Dynamic Material Flow Analysis of Perfluorooctane Sulfonate in China: 1985-2019

Perfluorooctane sulfonates (PFOS) are regarded as a category of chemicals with persistence, bioaccumulation, and toxicity. Understanding dynamic flows, stocks, and emissions of PFOS on a macro spatial and temporal scale can help provide a scientific basis for their sound management. In this work, a dynamic material flow analysis (d-MFA) model was built to characterize and analyze the cycles of PFOS in mainland China over the period 1985-2019. Flows, stocks, and environmental emissions were calculated and the sensitivity and uncertainty of the results were then analyzed. Results show that domestic production was the primary source of PFOS in China, most of which was flowed to the domestic market in the form of final products, with the remainder exported to international markets; soil and water were the main sinks of PFOS in China, with emissions from the usage stage contributing the largest portion (103 tons in 2019). The number of inflows and outflows were relatively low before 2000, but gradually increased until 2009 when the relevant convention was issued. Since 2005, in-use stocks and emissions of PFOS have grown yearly. In addition, stocks in landfill have been climbing since 1985. End-of-life management was still dominated by traditional methods, such as landfill and incineration, while there was a trend towards green treatments. This study can provide basic data and theoretical support for the sound management of PFOS in China.

Determinants for serum half-lives for linear and branched perfluoroalkyl substances after long-term, high exposure — a study in Ronneby, Sweden

BACKGROUND AND AIM: Per- and polyfluoroalkyl substances (PFAS) are persistent, ubiquitous substances with long elimination periods and various health effects. Although elimination rates and half-lives for PFAS have been described in both animal and human studies, few studies have explored the determinants behind the human elimination. The purpose of the current study was to estimate serum half-lives and the determinants for different PFAS. METHODS: Municipal drinking water contaminated with PFAS had been distributed to one third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from December, 2013. Between 2014 and 2018, 114 individuals aged between 4-84 from Ronneby participated in up to 10 serum sampling occasions. Potential determinants were collected at baseline, including Age, Sex, Body Mass Index, and estimated Glomerular Filtration Rate (eGFR). Urine was collected three times for calculating urine/serum ratio of PFAS, and faeces once for faecal calprotectin and zonulin. 19 PFAS were analyzed, and 8 of them were increased in Ronneby: perfluorooctanoic acid (PFOA), perfluoropentane sulfonate (PFPeS), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS), linear perfluorooctane sulfonate (L-PFOS) and three branched perfluorooctane sulfonates (1m-PFOS, 3/4/5m-PFOS and 2/6m-PFOS). RESULTS:The mean estimated half-lives (in years) were 2.47 (95%CI 2.27-2.7) for PFOA, 0.94 (0.86-1.02) for PFPeS, 4.52 (4.14-4.99) for PFHxS, 4.55 (4.14-5.06) for PFHpS, 2.73 (2.55-2.92) for L-PFOS, 5.01 (4.56-5.55) for 1m-PFOS, 3.43 (3.19-3.71) for 3/4/5m-PFOS, and 2.67 (2.51-2.85) for 2/6m-PFOS. Young age (14), females in fertile age (14-50), high eGFR (90 ml/min/1.73 m²), high urine/serum ratio, high calprotectin and low zonulin were associated with shorter half-lives. CONCLUSIONS:These results provide observational support for elimination routes – renal, faecal and maternal; are in line with past estimates for some PFAS such as PFOA; and are the first results for different PFOS isomers. KEYWORDS: PFAS, Environmental Epidemiology, Water Quality, Long-term exposure

Perfluorinated compounds disrupted osmoregulation in Oryzias melastigma during acclimation to hypoosmotic environment

Perfluorinated compounds (PFCs) are a type of ubiquitous contaminants spreading in the estuarine and coastal areas. Anadromous fish should deal with hypoosmotic challenge with PFCs stress during their migration from seawater to estuaries. However, few studies have been carried out to investigate the adverse impact of PFCs on fish osmoregulation and the underlying mechanism. In this study, Oryzias melastigma, an euryhaline fish model, were exposed to four representative PFC congeners including perfluorobutane sulfonate (PFBS), perfluorooctane sulfonates (PFOS), perfluorooctanoic acid (PFOA), and perfluorododecanoic acid (PFDoA) separately under both seawater and freshwater conditions. Histopathological changes in gills, ion homeostasis, Na+/K+-ATPase (NKA) activity, as well as the expression of related genes was detected upon exposure. Results showed that PFCs induced morphological changes in gills, disturbed the levels of major ions (Na+, Ca2+, Mg2+), and inhibited the NKA activity. Transcriptome analysis in fish gills during the acclimation to freshwater revealed that PFCs influenced the osmoregulation mainly by interfering with the endocrine system, signal transduction, as well as cellular community and motility. Validation with qRT-PCR confirmed that the mRNA expressions of osmoregulatory genes encoding hormones and receptors, as well as ion transmembrane transporters were disturbed by PFCs. Longer chain homolog (PFOS) showed a greater impact on osmoregulation than the shorter chain homolog (PFBS). Within the same carbon chain, sulfonic congener (PFOS) induced more serious injury to gills than carboxylic congener (PFOA). The interaction between PFCs and salinity varied in different adverse outcome. These results help to further understand the mechanism of how PFCs influence osmoregulation and elicit the need to assess the ecological risk of PFCs and other pollutants on anadromous migration.

Source emissions and climate change impacts on the multimedia transport and fate of persistent organic pollutants, Chaohu watershed, eastern China

Emission intensity and climate change control the transport flux and fate of persistent organic pollutants (POPs) in multiple environmental compartments. This study applied a multimedia model (BETR model) to explore alternations in the spatio-temporal trends of concentrations and transport flux of benzopyrene (BaP), phenanthrene (Phe), perfluorooctane sulfonates (PFOS) and polychlorinated biphenyls (PCBs) in the Chaohu watershed, located in the lower reaches of the Yangtze River, China in response to changes in source emissions and climate. The potential historic and future risks of these pollutants also were assessed. The results suggest that current trends in concentrations and transport were similar to that of their emissions between 2005 and 2018. During the next 100 years, temporal trends and spatial patterns were not predicted to change significantly, which is consistent with climate change. Based on sensitivity and correlation analyses, climate change had significant effects on multi-media concentrations and transport fluxes of BaP, Phe, PFOS and PCBs, and rainfall intensity was the predominant controlling factor. Risk quotients (RQs) of BaP and Phe-in soil increased from 0.42 to 0.95 and 0.06 to 0.35, respectively, from 2005 to 2090, indicating potential risks. The RQs of the other examined contaminants exhibited little potential risk in soil, water, or sediment. Based on spatial patterns, it was inferred that the ecosystem around Lake Chaohu is the most at risk. The study provides insights needed for local pollution control of POPs in the Chaohu watershed. In addition, the developed approach can be applied to other watersheds world-wide.

Mass Balance of Perfluorooctane sulfonates in a Semi-enclosed Bay, Korea

Mass Balance of Perfluorooctane sulfonates in a Semi-enclosed Bay, Korea

Enantioselectivity in transplacental transfer of perfluoro-1-methylheptanesulfonate (1m-PFOS): Human biomonitoring and in silico study

Perfluorooctane sulfonates (PFOS) are one of the most prominent perfluoroalkyl contaminants in humans and wildlife. Currently, information regarding enantiomer-specific exposure to PFOS in humans through transplacental transfer is lacking. This study examined 32 matched maternal serum, cord serum and placenta samples collected from mother-infant pairs in Wuhan, China. The enantiomer fraction (EF) value of perfluoro-1-methylhptanesulfonate (1m-PFOS) was lower in cord sera (0.362 ± 0.062, n = 23) compared to maternal sera (0.422 ± 0.048, n = 21) and placenta (0.410 ± 0.060, n = 16). Evaluations of the difference between EF1m-PFOS suggested enantioselective transplacental transfer of 1m-PFOS. In silico evaluation of the binding affinity of 1m-PFOS to human serum albumin (HSA) showed that the two 1m-PFOS enantiomers enantioselectively interacted with the HSA. This result hints the enantioselective carrier protein affinity may be a key factor for stereoselective 1m-PFOS transplacental transfer. The percentage of branched PFOS (%br-PFOS) and EF1m-PFOS was correlated in maternal sera, but not in cord sera and placentas. These data indicated that %br-PFOS and EF1m-PFOS may be less reliable in identifying PreFOS exposure when it comes to complex biological processes, such as transplacental transport. This study could expand our understanding of stereoselective placental contaminant transfer in humans.

Distribution and Bioaccumulation of Perfluoroalkyl Acids in Xiamen Coastal Waters

Since perfluoroalkyl acids (PFAs) are widely used and harmless to organisms, they have attracted great attention in recent years. The distribution of PFAs in the oceans all around the world is well documented. However, the study of PFAs in Xiamen could be a beneficial complement, for its unique geologies of no rivers that originate from other cities to influence the concentration of PFAs in this area. In this paper, six PFAs were analyzed in water, sediments, and organisms from both freshwater and seawater and the bioaccumulation factors (BAFs) were calculated with the quantity of PFAs in different trophic levels of aquatic organisms. The results showed that the ΣPFA concentrations ranged from 7.66 to 11.98 ng·L−1 for seawater samples and from 2.12 to 8.61 ng·L−1 for freshwater. The concentration of ΣPFAs in sediments was 7.43–12.89 ng·g−1 and 4.53–5.80 ng·g−1 in seawater and freshwater, respectively. The PFA concentration in water is highly positive correlated with the PFA concentration in sediments (R2 = 0.85). The calculated bioaccumulation factors (BCFs) were 6412–14254 L·kg−1 and 2927–7959 L·kg−1 for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonates (PFOS), respectively. PFOA seems more bioaccumulative than PFOS in seawater. The results illustrated the PFA pollution in the Xiamen sea area, and it is useful for the protection and control of the organic pollutants in this area.

Synthesis and characterization of a novel surfactant used for aqueous film-forming foam extinguishing agent

Fluorocarbon surfactants are a key ingredient of aqueous film-forming foam (AFFF) extinguishing agent. As is well known, the most widely used fluorocarbon surfactants are perfluorooctane sulfonates (PFOS) and theirs derivatives. However, PFOS has been restricted due to its drawbacks such as toxicity, bio-accumulation and resistance to biodegradation, etc. Fortunately, the toxicity and bio-accumulation can be neglected if the fluorocarbon chain contained in the surfactants is less than or equal to 4. Therefore, synthesis of novel short fluorocarbon chain (≤ C4) surfactants has become a very important way to solve this problem. A novel fluorocarbon surfactant based on perfluorobutyl had been synthesized and its chemical structure had been confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR) and 19F NMR measurements in this work. Since the fluorocarbon surfactant mixed with appropriate hydrocarbon surfactant can reduce its dosage and cutting production costs, the surface tension and the critical micelle concentration (CMC) of the synthesized fluorocarbon surfactant and its equimolar mixtures with CH3(CH2)5NaO3S had been studied. The results show that CMC and the surface tension at CMC (γCMC) of the pure surfactant were 21.68 mmol/L and 17.08 mN/m, while the minimum surface tension and CMC could reach to 16.58 mN/m and 7.72 mmol/L for the mixed system, respectively. In addition, the foamability, spreadability and extinguishing performance of the equimolar mixed system has also been investigated. The foam expansion and the 25% drainage time are 9.8 and 313 s, respectively, and the extinguishing times are less than 65 s while the burnback times are more than 14.50 min for all the hydrocarbon oils studied in this work, indicating a great application prospect in AFFF.

Multimedia fate and transport simulation of perfluorooctanoic acid/ perfluorooctanoate in an urbanizing area

Strong global demand leads to significant production of fluoropolymers (FP) in China which potentially release large quantities of perfluorooctanoic acid/perfluorooctanoate (collectively called PFOA/PFO) to the environment. Modelling the fate and transport of PFOA/PFO provides an important input for human health risk assessment. Considering the effects of urbanization and existing forms of PFOA/PFO, this study used the modified multispecies Berkeley-Trent-Urban-Rural model to simulate the transfer behavior of PFOA/PFO in the Bohai Rim, China. Spatial distributions of PFOA/PFO emissions during the year 2012 for the study area were illustrated. About two thirds of the total amount of PFOA/PFO was estimated to be released into fresh water, and the total releases to rural areas were 160-fold higher than those to urban areas due to the location of fluorochemical industrial parks. The simulations predicted that hydrosphere was the fate of PFOA/PFO, followed by soil and vegetation, which was consistent with field data. The highest PFOA/PFO concentration was modeled in the Xiaoqing River basin with a value of 32.57 μg/L. The PFOA/PFO concentrations in urban soils were generally higher than those in rural soils except for grids 1, 3 and 46. In addition, it was estimated that the total flux of PFOA/PFO entering into the Bohai Sea was 24.57 ton/year, 100-fold higher than that of perfluorooctane sulfonates (PFOS).