Global quantification of emerging and legacy per- and polyfluoroalkyl substances in indoor dust: Levels, profiles and human exposure.

This study investigated the occurrence and distribution of per- and polyfluoroalkyl substances (PFASs) in house dust samples from six regions across four continents. PFASs were detected in all indoor dust samples, with total median concentrations ranging from 17.3 to 197 ng/g. Among the thirty-one PFAS analytes, eight compounds, including emerging PFASs, exhibited high detection frequencies in house dust from all six locations. The levels of PFASs varied by region, with higher concentrations found in Adelaide (Australia), Tianjin (China), and Carbondale (United States, U.S.). Moreover, PFAS composition profiles also differed among regions. Dust from Australia and the U.S. contained high levels of 6:2 fluorotelomer phosphate ester (6:2 diPAP), while perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were predominant in other regions. Furthermore, our results indicate that socioeconomic factors impact PFAS levels. The assessment of human exposure through dust ingestion and dermal contact indicates that toddlers may experience higher exposure levels than adults. However, the hazard quotients of PFASs for both toddlers and adults were below one, indicating significant health risks are unlikely. Our study highlights the widespread occurrence of PFASs in global indoor dust and the need for continued monitoring and regulation of these chemicals.

Nationwide distribution of perfluoroalkyl ether carboxylic acids in Chinese diets: An emerging concern.

With the phase-out of perfluorooctanoic acid (PFOA) and its replacement by perfluoroalkyl ether carboxylic acids (PFECAs), there is a potential for increased exposure to various new PFECAs among the general population in China. While there are existing studies on dietary exposure to legacy perfluoroalkyl and polyfluoroalkyl substances (PFASs), research on dietary exposure to PFECAs, especially among the general Chinese populace, remains scarce. In the present study, we investigated the distribution of PFECAs in dietary sources from 33 cities across five major regions in China, along with the associated dietary intake. Analysis indicated that aquatic animal samples contained higher concentrations of legacy PFASs compared to those from terrestrial animals and plants. In contrast, PFECAs were found in higher concentrations in plant and terrestrial animal samples. Notably, hexafluoropropylene oxide dimer (HFPO-DA) was identified as the dominant compound in vegetables, cereals, pork, and mutton across the five regions, suggesting widespread dietary exposure. PFECAs constituted the majority of PFAS intake (57 %), with the estimated daily intake (EDI) of HFPO-DA ranging from 2.33 to 3.96 ng/kg bw/day, which corresponds to 0.78-1.32 times the reference dose (RfD) (3.0 ng/kg bw/day) set by the United States Environmental Protection Agency. Given the ubiquity of HFPO-DA and many other PFECAs in the nationwide diet of China, there is an urgent need for further research into these chemicals to establish relevant safety benchmarks or consumption advisory values for the diet.

Recovery of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) from water using foam fractionation with whey soy protein.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are persistent anthropogenic chemicals that are widely distributed in the environment and pose significant risks to human health. Foam fractionation has emerged as a promising method to recover PFOS/PFOA from water. However, PFOS/PFOA concentrations in wastewater are often inadequate to generate stable foams due to their high critical micelle concentrations and the addition of a cosurfactant is necessary. In this study, we developed whey soy protein (WSP) as a green frother and collector derived from soybean meal (SBM), which is an abundant and cost-effective agro-industrial residue. WSP exhibited excellent foaming properties across a wide pH range and demonstrated strong collection capabilities that enhanced the recovery of PFOS/PFOA. The mechanism underlying this collection ability was elucidated through various methods, revealing the involvement of electrostatic attraction, hydrophobic interaction, and hydrogen bonding. Furthermore, we designed a double plate internal to improve the enrichment of PFOS/PFOA by approximately 2.3 times while reducing water recovery. Under suitable conditions (WSP concentration: 300 mg/L, pH: 6.0, air flowrate: 300 mL/min), we achieved high recovery percentages of 94-98% and enrichment ratios of 7.5-12.8 for PFOS/PFOA concentrations ranging from 5 to 20 mg/L. This foam fractionation process holds great promise for the treatment of PFOS/PFOA and other per- and polyfluoroalkyl substances.

[Contamination levels of perfluorinated and polyfluoroalkyl compounds in breast milk and assessment of their exposure risk to infants].

The purposes of this study are to explore the contamination levels of perfluorinated and polyfluoroalkyl substances (PFASs) in breast milk and assess their exposure risk to infants. Based on data from a birth cohort study conducted in Yingcheng, Hubei Province, from 2018 to 2021, the contents of 23 types of PFASs in the breast milk of 324 pregnant women were determined using isotope dilution-high performance liquid chromatography-tandem mass spectrometry. Multiple linear regression was then performed to analyze the effects of various demographic characteristics and eating habits on the concentration of PFASs in breast milk. The daily PFASs intake of infants through breast milk was estimated, and the exposure risk of infants was also assessed. The results revealed that 23 types of PFASs in breast milk had good linear relationships in the range of 0.2-100 ng/mL, with correlation coefficients greater than 0.992. The limits of detection were 5-42 pg/mL, the limits of quantification were 15-126 pg/mL, the recoveries were 65.6%-108.1%, and the relative standard deviations were 1.6%-12.8%. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoate acid (PFOA), and perfluorohexanesulfonic acid (PFHxS), with median concentrations of 200.7, 63.5, and 25.2 pg/mL, respectively, were the main PFASs found in breast milk. The detection rates of these three contaminants were higher than 80%, whereas the detection rates of other compounds were lower than 45%. The results of multiple linear regression showed that older pregnant women and a higher frequency of pickled food intake may be related to increased PFAS levels in breast milk whereas a higher frequency of legume intake may be related to decreased PFAS levels in breast milk. The median estimated daily intakes (EDIs) of PFOS, PFOA, and PFHxS for infants were 25.1, 7.9, and 3.2 ng/(kg·d), respectively. In summary, this study found notable PFAS levels in breast milk in Yingcheng, Hubei Province. Among these PFASs, PFOS, PFOA, and PFHxS were the main contaminants. Maternal age as well as pickled food and legume intake may affect the PFAS level in breast milk. The health risk of PFAS intake through breast milk to some infants is worthy of attention and further study.

Human health risk-based soil generic assessment criteria of representative perfluoroalkyl acids (PFAAs) under the agricultural land use in typical Chinese regions.

Perfluoroalkyl acid substances (PFAAs), such as perfluorobutanoic acid (PFBA), perfluorobutanoic sulfonic acid (PFBS), perfluorooctane acid (PFOA) and perfluoroooctane sulfonic acid (PFOS) are frequently detected in the global environment and can cause potential health hazards even at low levels. In this study, quantitative human health risk assessment was undertaken to derive soil generic assessment criteria (GAC) for four PFAAs under the agricultural land scenario in the evaluated Chinese regions, which considered multiple exposure pathways including vegetables consumption, dermal absorption, ingestion of soil and dust, and exposure from non-soil sources. It is showed that the calculated GAC for four PFAAs in Guangdong and Shandong Provinces were less stringent than those in Zhejiang and Jiangsu Provinces, and Shanghai City, owing to the low exposure from non-soil sources in former two provinces. In addition, GAC of PFOS were the most stringent in the range of 0.28-0.50 µg kg-1 in the studied regions, followed by PFOA (1.36-2.20 µg kg-1), PFBA (42.59-68.03 µg kg-1) and PFBS (474.59-749.60 µg kg-1), mainly attributable to significantly more stringent toxicological values of PFOA and PFOS. Correspondingly, the potential health hazards exist for PFOA in the studied regions except Guangdong Province, and PFOS only in Zhejiang and Jiangsu Provinces as indicated by the hazard quotients ranging from 1.04 to 19.49, but no health hazards are identified for PFBA and PFBS. The dominant exposure pathway was found to be consumption of vegetables and attached soil for PFBA and PFBS, contributing to more than 93% of the total exposure, compared to 49.91-76.69% for PFOA and PFOS due to significant exposure from non-soil sources levels. Overall, this study provides a technical reference on how to derive scientifically justifiable soil GAC for representative PFAAs for maintaining and assessing soil quality and food safety internationally under the agricultural land use.

Meta-Analysis Comparing Nominal and Measured Concentrations of Perfluorooctanoic Acid and Perfluorooctane Sulfonate in Aquatic Toxicity Studies Across Various Experimental Conditions.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are among the most frequently detected chemicals among the per- and polyfluoroalkyl substances in aquatic environments. Because of their high detection frequency, persistence, and potential toxicity, interest in both PFOA and PFOS has increased in recent years. However, a substantial number of PFOA and PFOS toxicity tests only report nominal, or unmeasured, treatment concentrations, which may complicate the determination of protective values. In addition, previous literature has indicated that differences between nominal and measured concentrations of both PFOA and PFOS could be linked to experimental conditions (e.g., feeding regimes for test organisms, test vessel material [glass or plastic], use of solvent, and the presence of substrate). Therefore, this critical review examined whether nominal and measured concentrations were in close agreement with each other among the current PFOA and PFOS aquatic toxicity literature and if experimental conditions were associated with any observed differences. Nominal and measured concentrations in the current PFOA and PFOS aquatic toxicity literature generally displayed a high degree of linear correlation and relatively low median percent differences. Correlations between measured and nominal concentrations were >0.98 for PFOA and >0.95 for PFOS in freshwater tests across experimental conditions. For saltwater tests, correlations of >0.84 were observed for PFOA and PFOS (separate and combined) across experimental conditions. While measured PFOA and PFOS toxicity tests are generally preferred, the present meta-analysis demonstrated that experimental conditions had little influence on observed discrepancies between nominal and measured concentrations, with the exception of PFOS saltwater tests and PFOA and PFOS freshwater studies that contained substrate. Unmeasured tests with these conditions should be considered carefully based on project needs, with the caveat that the data sets for these two experimental conditions were limited. Environ Toxicol Chem 2023;42:2289-2301. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Environmental explanation of prostate cancer progression based on the comprehensive analysis of perfluorinated compounds.

Perfluorinated compounds (PFCs) are man-made chemicals used in the manufacture of many products with water and dirt repellent properties. Many diseases have been proved to be related to the exposure of PFCs, including breast fibroadenoma, hepatocellular carcinoma, breast cancer and leydig cell adenoma. However, whether the PFCs promote the progression of prostate cancer remains unclear. In this work, through comprehensive bioinformatics analysis, we discovered the correlation between the prostate cancer and five PFCs using Comparative Toxicogenomics Database (CTD), Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. In addition, further analysis showed that several PFCs-related genes demonstrated strong prognostic value for prostate cancer patients. The survival analysis and receiver operating characteristic (ROC) curves revealed that PFCs-related genes based prognostic model held great predictive value for the prognosis of prostate cancer, which could potentially serve as an independent risk factor in the future. In vitro experiments verified the promotive role of perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) in the growth of prostate cancer cells. This study provided novel insights into understanding the role of PFCs in prostate cancer and brought attention to the environmental association with cancer risks and progression.

Perfluoroalkyl substances in Romanian wastewater treatment plants: Transfer to surface waters, environmental and human risk assessment.

The current study aimed to determine the concentration levels of nine perfluoroalkyl substances (PFAS) in the five most significant Romanian wastewater treatment plants (WWTPs) and their transfer to natural receivers. The analytes were concentrated using a solid-phase extraction/ultrasonic-assisted extraction procedures and then selectively quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using electrospray ionization. In most of the wastewater samples investigated, the dominant compounds were perfluoropentanoic acid (PFPeA), perfluorooctanoic acid (PFOA), and perfluorooctansulfonate acid (PFOS), with the maximum concentration range between 105 and 316 ng/L in influents, 14.8-31.3 ng/L in effluents and removal efficiencies higher than 80 % for all selected PFAS compounds. In sewage sludge samples, PFOA and PFOS were the majority substances, with values up to 35.8 ng/g dw for PFOA and 27.8 ng/g dw for PFOS. PFOA and PFOS achieved the maximum levels by estimating mass loading and emission levels. As a result, 237 mg/day/1000 people of PFOA and 95.5 mg/day/1000 people of PFOS are entering daily in the WWTPs, while up to 31 mg/day/1000 people of PFOA and up to 13.6 mg/day/1000 people of PFOS are discharged daily into the natural emissaries. Human risk assessment shows that PFOA and PFOS are low to high risk for all age and gender categories. Children are the most exposed to PFOA and PFOS contamination in drinking water. Environmental risk assessment reveals that PFOA exhibits a low risk for some insect species, PFOS - a low risk for freshwater shrimps and a medium risk for midges, while perfluoroundecanoic acid (PFNuDA) could have a low to medium risk for midges. No assessment studies regarding the environmental and human risk of PFAS have been performed in Romania.

[Research on the establishment of standard limits for perfluorooctanoic acid and perfluorooctane sulfonate in the "Standards for Drinking Water Quality（GB5749-2022）"in China].

Perfluorinated compounds, especially Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are widely detected in water environments in China. Considering the potential health risks of drinking water exposure routes, PFOA and PFOS have been added to the water quality reference index of the newly issued "Standards for Drinking Water Quality (GB5749-2022)", with limit values of 40 and 80 ng/L, respectively. This study analyzed and discussed the relevant technical contents for determining the limits of the hygiene standard, including the environmental existence level and exposure status of PFOA and PFOS, health effects, derivation of safety reference values, and determination of hygiene standard limits. It also proposed prospects for the future direction of formulating drinking water standards.

PFAS levels in paired drinking water and serum samples collected from an exposed community in Central North Carolina.

The community of Pittsboro, North Carolina has been documented to have extensive per- and polyfluoroalkyl substances (PFAS) contamination in its drinking water source, the Haw River, over the last 20 years. However, a detailed exposure assessment has never been conducted. In this study, we sought to characterize the PFAS in paired drinking water and blood samples collected from a small cohort of Pittsboro residents (n = 49). Drinking water and serum from blood were collected from adults in late 2019 and early 2020 and were analyzed to quantify 13 PFAS analytes. In order to explore potential health effects of PFAS exposure, serum was further analyzed for clinical chemistry endpoints that could be potentially associated with PFAS (e.g., cholesterol, liver function biomarkers). PFAS were detected in all serum samples, and some serum PFAS concentrations were 2 to 4 times higher than the median U.S. serum concentrations reported in the general U.S. population. Of the 13 PFAS in drinking water, perfluorohexanoic acid (PFHxA) was measured at the highest concentrations. PFAS levels in the current drinking water were not associated with current serum PFAS, suggesting that the serum PFAS in this cohort likely reflects historical exposure to PFAS with long half-lives (e.g., PFOS and PFOA). However, one PFAS with a shorter half-life (PFHxA) was observed to increase in serum, reflecting the temporal variability of PFHxA in river and drinking water. Statistical analyses indicated that serum PFOA and PFHxS were positively associated with total cholesterol and non-HDL cholesterol. No serum PFAS was associated with HDL cholesterol. In the clinical chemistry analyses, serum PFHxA was found to be negatively associated with electrolytes and liver enzymes (e.g., AST and ALT), and serum PFOS was found to be positively associated with the ratio of blood urea nitrogen to creatinine (BUN:Cre). While small in size, this study revealed extensive exposure to PFAS in Pittsboro and associations with clinical blood markers, suggesting potential health impacts in community residents.

Perfluorinated compound correlation between human serum and drinking water: Is drinking water a significant contributor?

Perfluorinated compounds (PFASs) are a new artificial chemical. Due to its substantial toxicity and complex degradation in the natural environment, monitoring PFASs has become a hot issue for many researchers. Currently, the relationship between the concentration of PFASs in serum and the concentration of PFASs in drinking water is unclear. This paper aims to study the concentration levels of PFASs in drinking water and residents' serum in a city in northern China and the relationship between them. The results show that the concentration of PFASs in drinking water is low, and the average concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were 2.57 ± 0.69 ng/L and 0.30 ng/L, respectively, which were lower than the limits specified in China's newly introduced Standards for drinking water quality (GB 5749-2022). In the serum of residents, PFOA and PFOS were the two PFASs with the highest concentration. Spearman correlation analysis showed that perfluorohexane sulfonate (PFHxS) and PFOS concentrations were positively correlated with age, and PFHxS, PFOA, PFNA, and PFOS varied with sex. At the same time, the correlation analysis also showed no correlation between PFAS in drinking water and serum, indicating that drinking water was not the main factor causing the physical burden of PFAS in residents. The HI method was used to assess the health risks of PFASs to human beings. The risk entropy of all PFASs for human hepatotoxicity and reproductive toxicity is below 1.

Rapid, sensitive detection of PFOA with smartphone-based flow rate analysis utilizing competitive molecular interactions during capillary action.

Perfluorinated-alkyl substances (PFAS) pose an unmet threat to the public because they are not strictly monitored and regulated. Perfluorinated-carbon alkyl chains (PFOA), a type of PFAS, at 70 fg/µL is the current health and safety recommendation. Current testing methods for PFOA and PFAS chemicals include HPLC-MS/MS and molecularly imprinted polymers, which are expensive, time-consuming, and require training. In this work, PFOA and PFOS detection was performed on a paper microfluidic chip using competitive interactions between PFOA/PFOS, cellulose fibers, and various reagents (L-lysine, casein, and albumin). Such interactions altered the surface tension at the wetting front and, subsequently, the capillary flow rate. A smartphone captured the videos of this capillary action. The samples flowed through the channel in less than 2 min. Albumin worked the best in detecting PFOA, followed by casein. The detection limit was 10 ag/µL in DI water and 1 fg/µL in effluent (processed) wastewater. Specificity to other non-fluorocarbon surfactants was also tested, using anionic sodium dodecyl sulfate (SDS), non-ionic Tween 20, and cationic cetrimonium bromide (CTAB). A combination of the reagents successfully distinguished PFOA from all three surfactants at 100% accuracy. This low-cost, handheld assay can be an accessible alternative for rapid in situ estimation of PFOA concentration.

Historical Trend of Exposure to Perfluoroalkyl Surfactants PFOA, ADV, and cC6O4 and its Management in Two Perfluoroalkyl Polymers Plants, Italy.

OBJECTIVES: Perfluoroalkyl acid surfactants are used in the chemical industry for the synthesis of perfluoroalkyl polymers. In one Italian fluoropolymer plant and in the research and innovation center, two major perfluoroalkyl surfactants have been historically used: PFOA and ADV and a third, cC6O4 substituted PFOA from mid-2013. This work is summarizing occupational exposure to these chemicals in the period 2004-2021, assessed by biological monitoring. Moreover, taking advantage of the phasing out of PFOA, the elimination kinetics of PFOA in humans is investigated. METHODS: Workers exposed to PFOA (from beginning of the sixties to 2013), ADV (since 1996), and/or cC6O4 (since 2012) in the production of fluoropolymers, in the synthesis, research, and analysis, were periodically surveyed from 2004, measuring the concentration of perfluoroalkyl acid surfactants in serum. Workers of the same plants, not directly exposed, were surveyed as well. Applying the first-order kinetics model, the half-life of PFOA was calculated. RESULTS: 809 Workers were investigated with measurements of PFOA (n = 3692), ADV (n = 4288) and cC6O4 (n = 2272) in serum. In the production plant, median PFOA ranged from 1900 to 14 µg/l from 2004 to 2021; median ADV ranged from 434 to 86 µg/l from 2011 to 2021. For cC6O4 the detection percentage ranged from 9 to 47%; in detected samples median cC6O4 ranged from 3 to 16 µg/l in the period 2013-2021. Adopted mitigation measurements included: the phasing out of PFOA, the improvement of the plastomer and elastomer post-treatments; the reinforcement of the staff involved in prevention. Decreasing trends were observed for all chemicals along years (P value for linear trend of means < 0.01). For PFOA, a half-life of 3.16 (95% CI 2.98-3.37) years was calculated. CONCLUSIONS: In the study plants, several initiatives to reduce exposure and the risk associated with perfluoroalkyl surfactants were undertaken; results of biomonitoring show that they were effective, with a 5- to 136-fold reduction in the concentration of perfluoroalkyl compounds in the serum of workers.

An analysis of the use of the relative source contribution term in derivation of drinking water standards using perfluorooctanoic acid as an example.

The relative source contribution (RSC) term has long been used by the US Environmental Protection Agency (USEPA) and state regulatory agencies in setting criteria in water. The RSC reflects the proportion of the total daily intake of a chemical that can be derived from water when all other sources of exposure (e.g., food, air) are considered. This term is applied by the USEPA and state regulatory agencies when deriving ambient water quality criteria, maximum contaminant level goals, and drinking water health advisories for noncarcinogenic and threshold carcinogenic compounds. The value assigned to the RSC term affects the calculated criteria directly, with the allowable concentration in water decreasing with a decreasing RSC. A default RSC value of 20%-applied by regulatory entities in the USA for more than 40 years-assumes that 80% of an individual's exposure to a chemical's reference dose is from nonwater sources. Although the RSC is a chemical-specific parameter, there are few instances where a value other than the default of 20% has been approved and used. In 2000, USEPA outlined the process for developing chemical-specific RSC values, yet primary use of the default RSC value has continued since then. This article reviews USEPA's methodology for deriving chemical-specific RSC values and provides a case example using perfluorooctanoic acid (PFOA) to explore how the USEPA and state regulatory agencies are applying USEPA's guidance. The case study highlights inconsistent derivation of the RSC term, rooted in limitations in the current methodology. We suggest additional clarification of and more thoughtful use of the available data that may not meet USEPA's current adequacy requirements. We also recommend that the USEPA discuss recommendations for using biomonitoring data to set RSCs. Integr Environ Assess Manag 2023;19:605-612. © 2022 SETAC.

Two-in-one platform based on conjugated polymer for ultrasensitive ratiometric detection and efficient removal of perfluoroalkyl substances from environmental water.

Continuous emergence of persistent organic pollutants perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in various water bodies around the world poses a serious threat to the global ecosystem. The exploration of advanced detection/removal techniques to monitor/treat such type of toxicants is urgently required. Herein, we unveiled a donor-acceptor type conjugated polymer PF-DBT-Im as a first-of-its-kind ratiometric fluorescent probe for visual, amplified, and specific monitoring of PFOA and PFOS with ultra-low detection limits of 6.12 nM (PFOA) and 14.3 nM (PFOS), respectively. PF-DBT-Im undergoes strong aggregation after binding with PFOA/PFOS as evident by transmission electron microscopy, zeta potential measurements, and dynamic light scattering studies. This promotes interchain Förster resonance energy transfer process to endorse an obvious emission color change from blue-to-magenta under ultraviolet lamp excitation. Consequently, a smartphone-integrated portable device is fabricated for realizing rapid and on-site detection of PFOA/PFOS. Besides, a new class of magnetic adsorbent Fe3O4@NH2&F13 is also prepared and used in combination with PF-DBT-Im to remove PFOA/PFOS from the environmental water effectively and rapidly as confirmed by liquid chromatography-mass spectrometry analysis. Thus, utilizing the excellent signal amplification property of PF-DBT-Im and the remarkable magnetic separation capability of Fe3O4@NH2&F13, a multifunctional system is developed for step-wise recognition and separation of PFOA/PFOS from the environmental water proficiently and rapidly.

Research on the establishment of standard limits for perfluorooctanoic acid and perfluorooctane sulfonate in the "Standards for Drinking Water Quality（GB5749-2022）"in China / 中华预防医学杂志

Perfluorinated compounds, especially Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are widely detected in water environments in China. Considering the potential health risks of drinking water exposure routes, PFOA and PFOS have been added to the water quality reference index of the newly issued "Standards for Drinking Water Quality (GB5749-2022)", with limit values of 40 and 80 ng/L, respectively. This study analyzed and discussed the relevant technical contents for determining the limits of the hygiene standard, including the environmental existence level and exposure status of PFOA and PFOS, health effects, derivation of safety reference values, and determination of hygiene standard limits. It also proposed prospects for the future direction of formulating drinking water standards.

Physical and barrier changes in gastrointestinal mucus induced by the permeation enhancer sodium 8-[(2-hydroxybenzoyl)amino]octanoate (SNAC).

Drug delivery systems (DDS) for oral delivery of peptide drugs contain excipients that facilitate and enhance absorption. However, little knowledge exists on how DDS excipients such as permeation enhancers interact with the gastrointestinal mucus barrier. This study aimed to investigate interactions of the permeation enhancer sodium 8-[(2-hydroxybenzoyl)amino]octanoate (SNAC) with ex vivo porcine intestinal mucus (PIM), ex vivo porcine gastric mucus (PGM), as well as with in vitro biosimilar mucus (BM) by profiling their physical and barrier properties upon exposure to SNAC. Bulk mucus permeability studies using the peptides cyclosporine A and vancomycin, ovalbumin as a model protein, as well as fluorescein-isothiocyanate dextrans (FDs) of different molecular weights and different surface charges were conducted in parallel to mucus retention force studies using a texture analyzer, rheological studies, cryo-scanning electron microscopy (cryo-SEM), and single particle tracking of fluorescence-labelled nanoparticles to investigate the effects of the SNAC-mucus interaction. The exposure of SNAC to PIM increased the mucus retention force, storage modulus, viscosity, increased nanoparticle confinement within PIM as well as decreased the permeation of cyclosporine A and ovalbumin through PIM. Surprisingly, the viscosity of PGM and the permeation of cyclosporine A and ovalbumin through PGM was unaffected by the presence of SNAC, thus the effect of SNAC depended on the regional site that mucus was collected from. In the absence of SNAC, the permeation of different molecular weight and differently charged FDs through PIM was comparable to that through BM. However, while bulk permeation of neither of the FDs through PIM was affected by SNAC, the presence of SNAC decreased the permeation of FD4 and increased the permeation of FD150 kDa through BM. Additionally, and in contrast to observations in PIM, nanoparticle confinement within BM remained unaffected by the presence of SNAC. In conclusion, the present study showed that SNAC altered the physical and barrier properties of PIM, but not of PGM. The effects of SNAC in PIM were not observed in the BM in vitro model. Altogether, the study highlights the need for further understanding how permeation enhancers influence the mucus barrier and illustrates that the selected mucus model for such studies should be chosen with care.

Enhanced toxicity effects of iron particles together with PFOA in drinking water.

Iron particles present in drinking water distribution systems (DWDSs) could cause discoloration, while organic pollutants in DWDSs, such as perfluorooctanoic acid (PFOA), could be enriched by iron particles. However, little is known about the enhanced effects of PFOA and iron particles in DWDSs. To fill in these knowledge gaps, herein, iron-PFOA (FEP) particles were generated using residual chlorine as an oxidant in drinking water conditions and then separated into different sizes (ranging from small to large: FEP-S, FEP-M ，and FEP-L). FEP-S harbored the greatest cytotoxicity among the sizes. Interestingly, our data revealed that the PFOA released from FEP particles transformed into PFOS (perfluorooctane sulfonate) upon digestion in the gastrointestinal environment (GI), and FEP-L bored the strongest transformation, showing a toxicity profile that was distinct from that of FEP-S. Furthermore, mechanistic studies revealed that FEP per se should be accountable for the conversion of PFOA to PFOS dependent on the generation of hydroxyl radicals (·OH) in GI, and that FEP-L revealed the greatest production of ·OH. Collectively, these results showed how iron particles and PFOA could result in enhanced toxicity effects in drinking water: (i) PFOA could increase the toxicity of iron particles by reducing particle size and inducing higher generation of ·OH; (ii) iron particles could induce the transformation of PFOA into more toxic PFOS through digestion.

Perfluorooctanoic Acid Affects Thyroid Follicles in Common Carp (Cyprinus carpio).

Carp kidney is comprised of nephrons, hemopoietic tissue, and also hormonally-active thyroid follicles. Given this anatomical trait, it has been used to assess the thyroid disrupting potential of perfluorooctanoic acid (PFOA), a widespread and feared per- poly-fluoroalkyl substance and a persistent organic pollutant capable of interfering with the endocrine system in animals and humans. The occurrence and morphology of thyroid follicles in kidneys of carp experimentally exposed to 200 ng L-1 or 2 mg L-1 waterborne PFOA for 56 days were studied. The abundance of thyroid follicles was significantly higher and vesiculation increased in exposed fish as compared to controls. The number of vesiculated follicles/total number of follicles was positively correlated with PFOA blood concentration in fish exposed to the highest dose (2 mg L-1). The structure and ultrastructure of thyroid follicles were affected by PFOA also at the lower, environmentally relevant, concentration (200 ng L-1). Increased cellular projections, enhanced colloid endocytosis, rough endoplasmic reticulum enlargement and fragmentation and cytoplasm vacuolation were the main features displayed by PFOA-exposed carp. These results show that PFOA affects the occurrence and status of follicles and suggest the utility of fish kidney as a multipurpose biomarker organ in environmental pathology research, according to the One Health approach.

Estimation of Transport Parameters of Perfluoroalkyl Acids (PFAAs) in Unsaturated Porous Media: Critical Experimental and Modeling Improvements.

Predicting the transport of perfluoroalkyl acids (PFAAs) in the vadose zone is critically important for PFAA site cleanup and risk mitigation. PFAAs exhibit several unusual and poorly understood transport behaviors, including partitioning to the air-water interface, which is currently the subject of debate. This study develops a novel use of quasi-saturated (residual air saturation) column experiments to estimate chemical partitioning parameters of both linear and branched perfluorooctane sulfonate (PFOS) in unsaturated soils. The ratio of linear-to-branched air-water interfacial partitioning constants for all six experiments was 1.62 ± 0.24, indicating significantly greater partitioning of linear PFOS isomers at the air-water interface. Standard breakthrough curve analysis and numerical inversion of HYDRUS models support the application of a Freundlich isotherm for PFOS air-water interfacial partitioning below a critical reference concentration (CRC). Data from this study and previously reported unsaturated column data on perfluorooctanoate (PFOA) were reevaluated to examine unsaturated systems for transport nonidealities. This reanalysis suggests both transport nonidealities and Freundlich isotherm behavior for PFOA below the CRC using drainage-based column methods, contrary to the assertions of the original authors. Finally, a combined Freundlich-Langmuir isotherm was proposed to describe PFAA air-water interfacial partitioning across the full range of relevant PFAA concentrations.