Perfluorooctane Sulfonate Concentrations Research Articles

Long-term increase in mortality of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary following anthropic activities: Evidence from the stranded dolphin mortality analysis from 2003 to 2017

With the dramatic increase in anthropogenic threats to the Pearl River Estuary (PRE), the population size of the Indo-Pacific humpback dolphins (Sousa chinensis) has significantly decreased over the past decade. To understand the impact and potential risks of intense human activities on these dolphins, factors related to the mortality of humpback dolphins in the PRE were investigated by a detailed examination of 343 dolphin specimens stranded during 2003–2017. There was a significant (p < 0.01) increasing trend for humpback dolphin stranding, reflecting the accelerating rate of the population decline. A large proportion of strandings (35.88%) were neonates. A low recruitment rate implies slow population growth, and hence, limited capacity to resist anthropogenic stress. The most commonly diagnosed causes of death were vessel collision and net entanglement. The concentrations of trace metals, polychlorinated biphenyl (PCB) congeners, dichlorodiphenyltrichloroethane, polycyclic aromatic hydrocarbons, and most of per- and polyfluoroalkyl substances (PFASs) in the dolphin samples were greater than those previously reported in cetaceans globally. Furthermore, Cu, PCB77, PCB169, PCB81, PCB37, and PFASs (excluding PFBA, PFPeA, PFHxA, PFHxDA, and PFODA) were the major pollutants accumulated in neonates. 67% of PCB, 78% of Cu, and 100% of perfluorooctane sulfonate concentrations in the neonates exceeded the threshold for toxicological effects in marine mammals, suggesting that these compounds could be important factors contributing to the low survival rate of calves in this area. This study revealed that vessel transportation, fishing activities, and pollutant bioaccumulation are the three major causes of humpback dolphin mortality in the PRE. These results highlight the need for more efforts to restrict anthropogenic activities, especially vessel traffic, the catching of these marine animals and fishing, and pollutant discharge, in order to prevent vulnerable species from continuous population decline and further extinction.

Effects of Toxicants on Blood‐Brain Barrier Function in Resilient Versus Non‐resilient Mice

Environmental toxicants such as perfluorooctane sulfonate (PFOS), benzo‐a‐pyrene (BaP) and 2, 3, 7, 8‐tetrachlorodibenzo‐p‐dioxin (TCDD) can damage brain microvascular endothelial cells (BMECs), the primary component of the blood‐brain barrier (BBB). It is largely unknown whether differences in BBB phenotype contribute to people’s susceptibility to the neurological effects of environmental toxicants. We used a mouse model of psychological resilience to investigate effects of environmental toxicants on BBB function. In this model, C57BL/6 and Balb/c mice display “resilient” and “non‐resilient” phenotypes, respectively. We hypothesized that BaP, TCDD, and PFOS will affect BMECs of C57BL/6 mice differently than the BMECs of the Balb/c mice.BBB permeability was assessed by measuring transendothelial electrical resistance (TEER; ohms cm2) of primary adult mouse BMECs derived from C57BL/6 (cBMECs) or Balb/c (bBMECs) mice. Cells were treated with BaP (2, 10, 50 uM), TCDD (1.5, 15, 150 nM), PFOS (3, 30, 300 uM). After 24 hours, gene expression of occludin (Ocln), tight junction protein‐1 (Tjp‐1), claudin‐5 (Cldn‐5), and vascular cell adhesion molecule 1 (Vcam‐1) was measured by RT‐qPCR. Tetrazolium salt assay was used to measure cell viability. One‐ and two‐way ANOVA followed by Holm‐Sidak post‐hoc tests were performed to detect differences in TEER and cell viability (absorbance, nm). T‐tests were performed to compare RT‐qPCR data. Statistical significance was reached at p&lt;0.05. Experiments were performed with technical triplicates on 3 different days to obtain N=3/group.cBMECs displayed higher maximal TEER than bBMECs (1194±149 versus 628±64 ohms cm2; p&lt;0.01), and were significantly more sensitive to the TEER‐reducing effects of BaP (10 and 50 uM) after 1 hour of exposure (Holm‐Sidak, t’s&gt;5.24, p’s&lt;0.0002). This difference was maintained for 24 hours after treatment. After 1 hour of PFOS treatment (3 and 300 uM), TEER of bBMECs was significantly lower than that of the cBMECs (Holm‐Sidak, t’s&gt;3.173, p’s&lt;0.017). However, there was no difference in TEER between cell types at any other PFOS concentrations or time points. TCDD treatment induced a significant increase in TEER in both cBMECs and bBMECs over the course of 24 hours (ANOVA, p’s&lt;0.02), with no significant difference in TEER response to treatment between cell types. Although cell viability was higher in bBMECs, treatment with BaP, PFOS or TCDD did not differentially affect viability of the two cell types after 24 hours. Gene expression of Ocln, Cldn‐5, and Vcam‐1 were reduced only by the highest concentration of PFOS in both cell types (p’s&lt;0.04), while Tjp‐1 expression was not affected by any of the treatments across both cell types.Our study demonstrates that the BBB’s response to toxicants is dependent on the phenotype (resilient versus non‐resilient) of the individual, and that the difference in direction and magnitude of the response is toxicant‐specific. This suggests that the variability in BBB phenotype associated with psychological resilience may determine an individual’s susceptibility to the effects of environmental toxicants.

Associations of serum PFOA and PFOS levels with incident hypertension risk and change of blood pressure levels

Evidence on the associations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) with hypertension or blood pressure (BP) levels was limited and inconsistent. The present prospective study aims to evaluate the longitudinal associations of serum levels of PFOA and PFOS with incident hypertension risk and change of blood pressure levels. At baseline 1080 participants (mean age 62 years, 58.9% females) free of hypertension, cardiovascular disease, diabetes, and cancer were followed up for nearly 5 years. Baseline serum levels of PFOA and PFOS were measured with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Hypertension was defined as any of (1) self-reported physician-diagnosed hypertension (2) use of hypotension drugs (3) measured systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg. Change of BP was evaluated as a difference between twice measurements (BP at follow-up visit－BP at baseline). After adjustment for multiple covariates, serum PFOS levels were negatively correlated with risk of hypertension [RR per lg-unit = 0.94 (95% CI: 0.88, 0.99)] and change of systolic BP [β = −1.48 (95% CI: −2.56, −0.41)]. The highest vs lowest quartiles of PFOS concentration was negatively associated with hypertension risk. Compared with Q1, the RRs (95% CIs) for Q2, Q3, and Q4 were 0.83 (0.67–0.98), 0.81 (0.67–0.97), and 0.81(0.67–0.97), respectively (p for trend = 0.016). The negative associations remained in females but not in males (p for interaction = 0.44). No significant association of PFOA with hypertension risk was observed. Further studies are needed to validate our findings.

Association between serum per- and polyfluoroalkyl substances and thrombograms in young and middle-aged Taiwanese populations

PurposePer- and polyfluoroalkyl substances (PFAS) are a class of man-made chemicals used in many products. Recent in vitro and epidemiological reports have found that PFAS exposure can modify the function of platelets. Platelet size has been shown to affect platelet activity, and thrombograms are a simple method of indirect assessment of platelet function. However, there has been no large-scale research investigating the association between PFAS levels and complete thrombograms in humans. Approach and resultsIn the current cross-sectional study, we enrolled 1779 Taiwanese subjects (aged between 12 and 63 years) to study the associations between serum PFAS concentrations and thrombograms. There were 1175 men and 604 women with a mean age of 34.5 years. When all four PFAS were fitted by the multiple linear models at the same time, platelet counts decreased significantly with increasing quartiles of perfluorooctanoate acid (PFOA) and perfluorooctane sulfonate (PFOS), while platelet distribution width (PDW), mean platelet volume (MPV), and platelet-large cell ratio (PLCR) also increased significantly with increasing quartiles of PFOS. The mean platelet count was the lowest (264.02 k/µL [95% CI 256.00–272.04]; P < 0.001) when both PFOA and PFOS concentrations were above the 50th percentile. ConclusionsWe report that serum PFAS levels were correlated with thrombograms. If the association is etiologic, PFOA/PFOS may decrease the number of platelets, while PFOS may also increase the variation and the average size of platelets in the subjects of the study. Interestingly, PFOA and PFOS may have synergistic effects on the decrease in platelet counts. Further research is needed to study the effect of PFAS on platelets in humans.

Perfluorooctane sulfonate and perfluorooctanoic acid induce plasma membrane dysfunction in boar spermatozoa during in vitro capacitation

Spermatozoa require the capacitation, a series of biochemical events, to perform fertilization. Many toxic compounds can interfere in this process, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), which belong to the perfluoroalkyl substances (PFAS). Since both substances are found in many everyday materials and are highly persistent, they accumulate in organisms where they have been associated with fertility problems. This study analyzes the effects of PFOS and PFOA on the functionality of boar spermatozoa, and changes in the plasma membrane (PM) during capacitation. The median lethal concentrations (LC50) of PFOS and PFOA were 460 and 1894 µM, respectively, while the mean inhibitory concentrations of capacitation (ICC50) were 274 µM and 1458 µM, respectively. The ICC50 of PFOA was insufficient to reduce the capacitation, but 950 µM (½ LC50) of PFOA and the ICC50 of PFOS significantly reduced the number of capacitated spermatozoa. PFOS and PFOA also impeded the progesterone (P4)-induced acrosomal reaction (iAR). These effects occur despite the accumulation of [Ca2+]i under capacitating conditions. The accumulation of [Ca2+]i produces saturation, which prevents its entry through ionophore A23187 and P4 in the presence of PFOS. Membrane potential (Emv) was deregulated. Both PFAS affected lipid membrane conductance mediated by valinomycin. The spermatozoa presented 49% and 47% of membrane dysfunction with PFOS and PFOA, respectively. By causing membrane damage, both substances prevented the release of cholesterol and altered the organization of membrane microdomains (MMDs). Data indicate that both PFAS caused alterations in PM functionality.

Perfluorooctanoate and perfluorooctane sulfonate in umbilical cord blood and child cognitive development: Hamamatsu Birth Cohort for Mothers and Children (HBC Study)

BackgroundPrenatal exposure to per- and polyfluoroalkyl substances (PFAS) has been shown to affect offspring behaviors in laboratory animals. Several epidemiological studies investigated associations between prenatal PFAS exposure and child neurodevelopment, but results were inconclusive. We examined associations between cord blood concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) and cognitive development in children from 4 to 40 months of age. MethodsThis study included 598 mother–child pairs who participated in the Hamamatsu Birth Cohort Study for Mothers and Children (HBC Study), a prospective birth cohort study in Japan. PFOA and PFOS were quantified in cord blood. The Mullen Scales of Early Learning (MSEL) was used to assess child cognitive function at 4, 6, 10, 14, 18, 24, 32, and 40 months of age. For each of log 2-transformed PFOA and PFOS concentrations, we examined: 1) associations with the scores of MSEL Early Learning Composite (Composite) and four subscales (Fine Motor, Visual Reception, Receptive Language, Expressive Language) at each assessment time point; and 2) associations with longitudinal changes in the Composite and subscale scores. ResultsMSEL Composite scores were inversely associated with PFOA at 18 months of age (per 2-fold increase in concentration: β = -2.23, 95% CI: -3.91, -0.56), but not at other ages. When accounting for changes in scores from 4 to 40 months of age, PFOA and PFOS were positively associated with Composite as well as Receptive and Expressive Language scores. Child’s sex modified associations between PFOA and Composite scores at 14, 18, and 40 months and those between PFOS and Composite scores at 14 months, showing negative associations among females. ConclusionsIn this study, cord blood PFOA and PFOS concentrations showed mixed associations with child cognitive functions at specific age but had positive associations with longitudinal changes in cognitive development from 4 to 40 months of age.

Perfluoroalkyl Substances (PFASs) in the Canadian Freshwater Environment

Per- and polyfluoroalkyl substances (PFASs) are anthropogenic substances that are very stable in the receiving environment. Legacy perfluoroalkane sulfonates (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) are especially persistent and resistant to typical environmental degradation processes and therefore are distributed across all trophic levels and environmental compartments (soil, air, water). Since most uses of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and LC-long-chain PFCAs are banned in Canada, alternative PFASs have been in use for a number of years. Twenty-nine sites across Canada were sampled for PFASs to determine concentrations and trends. Overall, 13 PFASs were measured in 566 Canadian freshwater samples from 2013 to 2020 with a range from below the detection limit (LOD range: 0.4–1.6 ng/L) of the laboratory to a maximum of 138 ng/L (for PFBS). While PFOS and PFOA concentrations are declining significantly over time, other compounds such as PFPeA and PFBA have increased significantly over 2013–2020. Overall, the range of concentrations found in this study was similar to that of other Canadian and international studies. However, this study also found a higher frequency of detections of the replacement PFASs than that of the other, older, Canadian studies.

Graphene oxide chronic exposure enhanced perfluorooctane sulfonate mediated toxicity through oxidative stress generation in freshwater clam Corbicula fluminea

Graphene oxide (GO), a frequently utilized graphene family nanomaterial, is inevitably released into the aquatic environment and interacts with organic pollutants, including perfluorooctane sulfonate (PFOS), a well-known persistent organic pollutant. To determine the adverse effects of GO chronic exposure on PFOS bioaccumulation and toxicity, adult freshwater bivalves, namely Asian clams (Corbicula fluminea) were treated for 28 days with PFOS (500 ng/L) and different concentrations of GO (0.2, 1, 5 mg/L) as PFOS single and GO single exposure groups, as well as PFOS-GO mixture exposure groups. Our results demonstrated that the bioaccumulation of PFOS was significantly enhanced by co-exposure in gills and visceral masses, which was 1.64–2.91 times higher in gills than in visceral masses. Both single, as well as co-exposure, caused a significant reduction in clams’ siphoning behavior, compared to the controls. Further, the co-exposure significantly increased the production of reactive oxygen species (ROS), exacerbating malondialdehyde (MDA) content, enhancing superoxide dismutase (SOD) and catalase (CAT), while decreasing glutathione reductase (GR) and glutathione S-transferase (GST) enzymatic activities in clam tissues. And co-exposure significantly altered the expressions of se-gpx, sod, cyp30, hsp40, and hsp22 genes (associated with oxidative stress and xenobiotic metabolism) both in gills and visceral masses. Moreover, co-exposure caused significant histopathological changes such as cilia degradation in the gills, expansion of tubule lumens in digestive glands, and oocyte shrinkage in gonads. Finally, the enhanced integrated biomarker response (EIBR) index revealed that co-exposure to 500 ng/L PFOS + 1 mg/L/5 mg/L GO was the most stressful circumstance. Overall, our findings suggested that the presence of GO increased PFOS bioaccumulation in tissues, inducing multifaceted negative implications at molecular and behavioral levels through oxidative stress generation in Asian clams.

Carbon-dot hydrogels as superior carbonaceous adsorbents for removing perfluorooctane sulfonate from water

Efficiently removing perfluorooctane sulfonate (PFOS) from wastewaters is a hot topic in environmental field. Herein, crosslinking the nano-sized and zero-dimensional carbon dots (CDs) with polyethylene glycol diglycidyl ether (PEG) and polypropylene glycol diglycidyl ether (PPG) resulted in CD hydrogels that were verified by TEM, SEM, FTIR and XPS. The obtained CD hydrogels could efficiently adsorb PFOS from water through their CD moieties. The kinetic curves were fitted well by the pseudo-second order model, indicating the involvement of chemisorption in the rate-limiting step. The adsorption isotherm measurements showed that the hydrogel with the highest CD content had a PFOS maximum uptake capacity of ca. 2.82 g/g (5.64 mmol/g) in the neutral water, which was much higher than the ever-reported carbonaceous materials, and also ranked the top three among the superior positively-charged adsorbents. The superior PFOS adsorption of CD hydrogels could be attributed to good dispersion of the nanoscale CDs in the PEG/PPG hydrogel matrix, leading to the substantial exposure of the binding sites of CDs towards PFOS molecules. Moreover, CD hydrogels did not show pronounced loss of adsorption capacity after experiencing five adsorption-desorption cycles. As for the real wastewaters, CD hydrogels could efficiently treat not only the high concentration of PFOS in the neutral firefighting wastewaters, but also the extremely low concentration of PFOS in the neutral environmental wastewater, where the residual PFOS concentration could be reduced less than 5 ng/L, satisfying the standard of the U.S. Environmental Protection Agency.

Sorption and partitioning of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) onto sediments of Diep and Plankenburg river systems Western Cape, South Africa

Partitioning behaviour of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in sediments obtained from river systems were investigated in this study. The partitioning coefficient (log K OC ) and distribution coefficient (log K D ) of PFOA and PFOS between sediments and the aqueous solution were estimated from the sorption data. Levels of PFOA and PFOS in the sediment samples ranged between 30.01–191.96 ng/g dw and 0.50–248.14 ng/g dw, respectively. The kinetic study showed that the time required for equilibrium was <400 min for the compounds. Sediment samples SS-C provided the highest sorption capacities (0.11 and 0.13 mg/g) for both PFOA and PFOS. Sorption studies revealed that the removal kinetics fitted well into the Elovich rate equation (R 2 = 0 . 98 and 0.92) followed by the pseudo-second-order kinetic model (R 2 = 0 . 91 and 0.89) for PFOA and PFOS, respectively. Mean values for the partitioning coefficient (log K OC ) in the river systems were 1.04 ± 0.26 and 1.85 ± 0.65 (cm 3 /g) for PFOA and PFOS respectively. Partitioning coefficient (log K OC ) significantly (p < 0.05) increased over time. This study represents the first report on partitioning and distribution of PFOA and PFOS in sub-Sahara Africa, which provide data and a scientific base to understand the fate and sorption of PFOA and PFOS in an aquatic system. The findings showed that lower pH values and increasing ionic strength favours sorption and partitioning of perfluoroalkyl substances (PFAS) in aqueous solution onto sediments; hence, plays an important role in their availability in water. Presence of PFAS in the aquatic system sediments is a potential risk to organisms. • Maximum concentration of PFOA and PFOS in the sediments from the river systems were 191.9 and 248.1 ng/g dw, respectively. • Mean values for the log K OC in the river systems were 1.04 ± 0.2 and 1.85 ± 0.6 (cm 3 /g) for PFOA and PFOS respectively. • Sorption kinetics for PFOA and PFOS fitted well into the elovich rate equation for the investigated sediment samples. • Lower solution pH and increase in Ca 2 + concentration favours the sorption and partitioning behaviour of PFOA and PFOS.

Current Breast Milk PFAS Levels in the United States and Canada: After All This Time, Why Don't We Know More?

Background:Despite 20 y of biomonitoring studies of per- and polyfluoroalkyl substances (PFAS) in both serum and urine, we have an extremely limited understanding of PFAS concentrations in breast milk of women from the United States and Canada. The lack of robust information on PFAS concentrations in breast milk and implications for breastfed infants and their families were brought to the forefront by communities impacted by PFAS contamination.Objectives:The objectives of this work are to: a) document published PFAS breast milk concentrations in the United States and Canada; b) estimate breast milk PFAS levels from maternal serum concentrations in national surveys and communities impacted by PFAS; and c) compare measured/estimated milk PFAS concentrations to screening values.Methods:We used three studies reporting breast milk concentrations in the United States and Canada We also estimated breast milk PFAS concentrations by multiplying publicly available serum concentrations by milk:serum partitioning ratios for perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorononanoic acid (PFNA). Measured and estimated breast milk concentrations were compared to children’s drinking water screening values.Discussion:Geometric means of estimated breast milk concentrations ranged over approximately two orders of magnitude for the different surveys/communities. All geometric mean and mean estimated and measured breast milk PFOA and PFOS concentrations exceeded drinking water screening values for children, sometimes by more than two orders of magnitude. For PFHxS and PFNA, all measured breast milk levels were below the drinking water screening values for children; the geometric mean estimated breast milk concentrations were close to—or exceeded—the children’s drinking water screening values for certain communities. Exceeding a children’s drinking water screening value does not indicate that adverse health effects will occur and should not be interpreted as a reason to not breastfeed; it indicates that the situation should be further evaluated. It is past time to have a better understanding of environmental chemical transfer to—and concentrations in—an exceptional source of infant nutrition. https://doi.org/10.1289/EHP10359

Effects of long-term perfluorooctane sulfonate (PFOS) exposure on activated sludge performance, composition, and its microbial community

The widespread presence and persistence of perfluorooctane sulfonate (PFOS) in wastewater treatment plants, as well as its toxicity and bioaccumulation potential, necessitates the investigation on their impact on bioreactor performance. A 48-day exposure test was adopted to study the effects of low (10 μg L-1) and high (1000 μg L-1) PFOS concentrations in a sequencing batch reactor on the performance, composition, and microbial community of activated sludge. The results suggested that adding PFOS at low and high concentrations lowered the removal efficiency of total nitrogen by 22.48% (p < 0.01) and 16.30% (p < 0.01) respectively, while enhanced that of total phosphorus by 1.87% (p > 0.05) and 7.07% (p < 0.05) respectively, compared with the control group. The addition of PFOS also led to the deterioration of activated sludge dewatering performance. Composition and spectroscopic measurements revealed that the PFOS dosage changed the composition of the activated sludge. Furthermore, the PFOS altered the structure and function of the activated sludge microbial community as well as key enzyme activities.

A highly sensitive dual-readout assay for perfluorinated compounds based CdTe quantum dots

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) are two typical perfluorinated compounds (PFCs) that poss potential ecological toxicity. In this work, a fluorescence and resonance light scattering (RLS) dual-readout strategy for the detection of PFCs at picomole level based on the water-soluble CdTe quantum dots (CdTe QDs) has been proposed. It is found that the CdTe QDs exhibit a quenching in the presence of PFCs and thus serve as useful probes for PFCs. The linear ranges are 0.032–10.0 nM with a limit of detection(LOD) of 32.02 pM for PFOA and 0.044–15.0 nM with a LOD of 43.96 pM for PFOS, respectively. Meanwhile, PFCs can form complexes with CdTe QDs in acid medium, resulting in remarkable RLS signals. The enhanced RLS intensities are in proportion to the concentrations of PFOA and PFOS, respectively. And the linear ranges are 0.048–5.0 nM with a LOD of 47.78 pM for PFOA, and 0.057–5.0 nM with a LOD of 56.72 pM for PFOS, respectively. This dual-mode detection increases the reliability of the measurement. The proposed method is simple, sensitive and cost-effective, with potential applications in environmental monitoring and assessment.

The role of mouse and human peroxisome proliferator-activated receptor-α in modulating the hepatic effects of perfluorooctane sulfonate in mice

Perfluorooctane sulfonate (PFOS) is a stable environmental contaminant that can activate peroxisome proliferator-activated receptor alpha (PPARα). In the present work, the specific role of mouse and human PPARα in mediating the hepatic effects of PFOS was examined in short-term studies using wild type, Ppara-null and PPARA-humanized mice. Mice fed 0.006 % PFOS for seven days (∼10 mg/kg/day), or 0.003 % PFOS for twenty-eight days (∼5 mg/kg/day), exhibited higher liver and serum PFOS concentrations compared to controls. Relative liver weights were also higher following exposure to dietary PFOS in all three genotypes as compared vehicle fed control groups. Histopathological examination of liver sections from mice treated for twenty-eight days with 0.003 % PFOS revealed a phenotype consistent with peroxisome proliferation, in wild-type and PPARA-humanized mice that was not observed in Ppara-null mice. With both exposures, expression of the PPARα target genes, Acox1, Cyp4a10, was significantly increased in wild type mice but not in Ppara-null or PPARA-humanized mice. By contrast, expression of the constitutive androstane receptor (CAR) target gene, Cyp2b10, and the pregnane X receptor (PXR) target gene, Cyp3a11, were higher in response to PFOS administration in all three genotypes compared to controls for both exposure periods. These results indicate that mouse PPARα can be activated in the liver by PFOS causing increased expression of Acox1, Cyp4a10 and histopathological changes in the liver. While histopathological analyses indicated the presence of mouse PPARα-dependent hepatic peroxisome proliferation in wild-type (a response associated with activation of PPARα) and a similar phenotype in PPARA-humanized mice, the lack of increased Acox1 and Cyp4a10 mRNA by PFOS in PPARA-humanized mice indicates that the human PPARα was not as responsive to PFOS as mouse PPARα with this dose regimen. Moreover, results indicate that hepatomegaly caused by PFOS does not require mouse or human PPARα and could be due to effects induced by activation of CAR and/or PXR.

Preliminary investigation of the presence of PFOS and PFOA in water and sediment in Cau river

Perfluoro-octane sulfonate (PFOS) and Perfluoro-octanoic acid (PFOA) are recognised as emerging environmental pollutants because of their high persistence in various environmental matrices and toxic effects on humans and animals. The objectives of this study were to preliminarily investigate the occurrence of PFOS and PFOA in the water and sediment of the Cau river in Thai Nguyen city. The concentration of PFOS and PFOA in water ranged from &lt;LOQ-0.67 ng/l and 0.05-8.11 ng/l; 1.19-4.73 ng/g, and 0.17-1.78 ng/g in sediment, respectively. The highest total concentrations of PFOS and PFOAwere recorded in the areas that directly received wastewater from domestic and industrial activities. The water-sediment distribution coefficient (Kd) was relatively different for PFOS and PFOA, with Kd ranged from 20.51-72.83 l/g and 1.21-20.31 l/g for PFOS and PFOA, respectively. This result suggested the distribution of PFOS and PFOA between water and sediment, in which PFOS will preferentially deposit in the sediment, and PFOA will tend to distribute in the liquid phase of the aquatic environment.

Performance testing of mesh anodes for in situ electrochemical oxidation of PFAS

Groundwater remediation technologies that can destroy per- and polyfluoroalkyl substances (PFAS) in situ are in high demand. To address this need, using flow-through electrochemical reactors we compared the performance of three mesh electrode materials that may be implemented in the subsurface as permeable reactive barriers. A Magnéli-phase titanium suboxides TinO2n-1 anode achieved higher perfluorooctane sulfonate (PFOS) oxidation rates and lower energy consumption than boron-doped ultrananocrystalline diamond and IrO2-Ta2O5 mixed metal oxides, and was thus selected for more detailed testing regarding the impacts of varying current density, flow velocity, electrolyte conductivity, and PFOS concentration. Over 99% of PFOS removal was achieved under continuous flow conditions. The fluorine mass balance showed that most PFOS-bonded F was released as fluoride, while no organic intermediates were detected in the aqueous phase. Each ∼2% of fluorine was recovered as HF and organofluorine intermediates in the gas phase. A comparison of 10 PFAS revealed a hydrophobicity-driven increase in oxidation rate with increasing perfluoroalkyl chain length as well as faster oxidation kinetics for perfluoroalkyl carboxylic acids compared to perfluoroalkane sulfonic acids, likely due to contributions from electrochemically activated sulfate. The energy consumption of PFAS treatment under simulated slow-flow groundwater conditions was substantially higher than in ex situ electrochemical systems optimized for enhanced mass transfer. Consequently, future work should focus on in situ treatment design optimization with an emphasis on power requirements. Collectively, our investigations demonstrate that among the few water treatment technologies capable of breaking the carbon-fluorine bond, electrochemical treatment is a promising approach for in situ destruction of PFAS in the subsurface.

Perfluorooctane sulfonate (PFOS) induces several behavioural defects in Caenorhabditis elegans that can also be transferred to the next generations

Perfluorooctane sulfonate (PFOS) is a well-known global persistent organic pollutant of grave concern to ecological and human health. Toxicity of PFOS to animals and humans are well studied. Although few studies have reported the behavioral effect of PFOS on nematode Caenorhabditis elegans, it's transgenerational effects were seldom studied. Therefore, we investigated the toxicity of PFOS on several behavioral responses besides bioaccumulation and transgenerational effects in C. elegans. In contrast to the several published studies, we used lower concentrations (0.5–1000 μg/L or 0.001–2.0 μM) that are environmentally relevant and reported to occur close to the contaminated areas. The 48 h median lethal concentration of PFOS was found to be 3.15 μM (1575 μg/L). PFOS (≥0.01 μM) caused severe toxicity to locomotion, and this effect was even transferred to progeny. However, after a few generations, the defect was rectified in the progeny of single-time exposed parent nematodes. Whereas, continuous exposure at 0.001 μM PFOS, no visible defects were observed in the progeny. PFOS (≥0.01 μM) also significantly decreased the brood size in a concentration-dependent manner. Besides, lifespan was affected by the higher concentration of PFOS (≥1.0 μM). These two behavioral endpoints, lifespan and reproduction defects, became less severe in the progeny. Chemotaxis plasticity was also significantly retarded by ≥ 1.0 μM PFOS compared to the control group. Results indicate that PFOS can exert severe neurobehavioral defects that can be transferred from parents to their offspring. The findings of this study have significant implications for the risk assessment of perfluorinated substances in the environment.

Umbilical cord serum concentrations of perfluorooctane sulfonate, perfluorooctanoic acid, and the body mass index changes from birth to 5 1/2\xa0years of age

Prenatal exposure to perfluoroalkyl substances (PFAS) has been reported to affect body weight from birth to childhood, but the results remain inconclusive. We investigated whether umbilical cord blood concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are associated with children’s risk trajectory for obesity. 600 children were randomly selected from the Hamamatsu Birth Cohort for Mothers and Children (HBC study) and their umbilical cord serum PFAS concentrations were quantified. Participants underwent BMI measurements at ages 1, 4, 10, 18, 24, 32, 40, 50, and 66 months. Growth curve modeling with random intercept was performed with standardized BMI as outcome variable. PFOS was negatively associated with standardized BMI (β = − 0.34; p = 0.01), with a marginally significant interaction with the child’s age (β = 0.0038; p = 0.08). PFOA was negatively associated with standardized BMI (β = − 0.26, 95% CI − 0.51, 0; p = 0.05), with a significant interaction with the child’s age (β = 0.005; p = 0.01). Stratified analysis by sex revealed that these effects were significant only among girls. Prenatal exposure to PFAS initially was associated with lower standardized BMI during infancy, but this effect dissipated over time and reversed in direction during later childhood. The effects of prenatal PFAS on higher standardized BMI is stronger in girls.

A water-soluble fluorescence probe based on perylene diimide for rapid and selective detection of perfluorooctane sulfonate in 100% aqueous media

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/PFOScomplex 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.

Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) in Surface Water of China: National Exposure Distributions and Probabilistic Risk Assessment.

This study presents a comprehensive application of the probabilistic risk assessment methodology for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), which are two types of perfluoroalkyl acids frequently studied in recent years. The exposure characteristics of PFOA and PFOS in Chinese surface water on a nationwide scale were summarized. Individual predicted no-effect concentration (PNEC) and the sensitivities for taxonomic groups of primary producers, invertebrates, and vertebrates were derived by the species sensitivity distributions method. Both hazard quotients (HQs) and joint probability curves were calculated to assess the risks to aquatic organisms. Among seven Chinese river basins, the mean concentrations of PFOA and PFOS in the Yangtze River Basin were the highest (58ng/L and 22ng/L, respectively), while the lowest concentrations (< 1ng/L) were in the Songhua River Basin. The acute PNEC value was 2.43mg/L for PFOA and 0.96mg/L for PFOS, and the chronic PNEC value was 0.0067mg/L for PFOA and 0.0012mg/L for PFOS, respectively. The sensitivities of different taxonomic groups revealed higher sensitivity of primary producers for PFOA and higher sensitivity of invertebrates for PFOS. The acute HQs of PFOA and PFOS were less than 1. The probabilities of exposure concentrations exceeding 5th percentile toxicity value of the chronic data for all aquatic organisms were 1.65% for PFOA and 1.23% for PFOS, respectively, suggesting a low probability of effects to aquatic organisms. Compared with the risk scenarios worldwide, the ecological risks for chronic effects decreased in the order of PFOS (worldwide) > PFOA (China) > PFOS (China) > PFOA (worldwide).