Polyfluoroalkyl Substances Concentrations Research Articles

Per- and Polyfluoroalkyl Substances (PFAS) Accumulation, Reproductive Impairment, and Associations with Nestling Body Condition in Great (Parus major)- and Blue Tits (Cyanistes caeruleus) Living near a Hotspot in Belgium.

Due to the limited number of field studies investigating associations between environmentally relevant per- and polyfluoroalkyl substances (PFAS) mixtures and reproductive impairment, there is uncertainty as to whether birds are affected by PFAS pollution, whether species differ in sensitivity to PFAS, and whether the observed reproductive impairment is caused by PFAS or rather due to other potential confounding variables. Therefore, we investigated PFAS concentrations in eggs and blood plasma of great tit (Parus major) and blue tit (Cyanistes caeruleus) nestlings near a PFAS hotspot in Belgium, reproductive impairment, and associations between the accumulated levels and nestling body condition. In total, 29 eggs and 22 blood plasma samples of great tit clutches, and 10 egg and 10 blood plasma samples of blue tit clutches, were collected. Despite more types of PFAS being detected in eggs compared to plasma, only minor differences in profiles were observed between species. On the other hand, tissue-specific differences were more pronounced and likely reflect a combination of maternal transfer and dietary exposure post-hatching. Despite the high concentrations detected in both species, limited reproductive impairment was observed. Our results support previous findings that great tits and blue tits may not be very susceptible to PFAS pollution and provide evidence that other factors, including ecological stoichiometry, may be more important in explaining inter-species variation in PFAS accumulation and reproductive impairment.

Per- and polyfluoroalkyl substances (PFAS) in homegrown crops: Accumulation and human risk assessment

Homegrown crops can present a significant exposure source of per- and polyfluoroalkyl substances (PFAS) to humans. Field studies studying PFAS accumulation in multiple vegetable food categories and examining the potential influence of soil characteristics on vegetable bioavailability under realistic exposure conditions are very scarce. Crop PFAS accumulation depends on a complex combination of factors. The physicochemical differences among the numerous PFAS makes risk assessment very challenging. Thus, simplification of this complexity into key factors that govern crop PFAS accumulation is critical. This study analyzed 29 targeted legacy, precursor and emerging PFAS in the vertical soil profile (0–45 cm depth), rainwater and edible crop parts of 88 private gardens, at different distances from a major fluorochemical plant. Gardens closer to the plant site showed higher soil concentrations which could be linked with historical and recent industrial emissions. Most compounds showed little variation along the soil depth profile, regardless of the distance from the plant site, which could be due to gardening practices. Annual crops consistently accumulated higher sum PFAS concentrations than perennials. Highest concentrations were observed in vegetables, followed by fruits and walnuts. Single soil-crop relationships were weak, which indicated that other factors (e.g., porewater) may be better measures of bioavailability in homegrown crop accumulation. Regression models, which additionally considered soil characteristics showed limited predictive power (all R2 ≤ 35%), possibly due to low variability in crop concentrations. Human intake estimations revealed that the PFAS exposure risk via crop consumption was similar nearby and remotely from the plant site, although the contribution to the overall dietary exposure can be relatively large. The tolerable weekly intake was frequently exceeded with respect to fruit and vegetable consumption, thus potential health risks cannot be ruled out.

Identification of Emerging Per- and Polyfluoroalkyl Substances (PFAS) in E-waste Recycling Practices and New Precursors for Trifluoroacetic Acid.

Electronic waste is an emerging source of per- and polyfluoroalkyl substance (PFAS) emissions to the environment, yet the contribution from hazardous recycling practices in the South Asian region remains unclear. This study detected 41 PFAS in soil samples from e-waste recycling sites in Pakistan and the total concentrations were 7.43-367 ng/g dry weight (dw) (median: 37.7 ng/g dw). Trifluoroacetic acid (TFA) and 6:2 fluorotelomer sulfonic acid emerged as the dominant PFAS, constituting 49% and 13% of the total PFAS concentrations, respectively. Notably, nine CF3-containing emerging PFAS were identified by the high-resolution mass spectrometry (HRMS)-based screening. Specifically, hexafluoroisopropanol and bistriflimide (NTf2) were consistently identified across all the samples, with quantified concentrations reaching up to 854 and 90 ng/g dw, respectively. This suggests their potential association with electronic manufacturing and recycling processes. Furthermore, except for NTf2, all the identified emerging PFAS were confirmed as precursors of TFA with molar yields of 8.87-40.0% by the TOP assay validation in Milli-Q water. Overall, this study reveals significant emission of PFAS from hazardous e-waste recycling practices and emphasizes the identification of emerging sources of TFA from precursor transformation, which are essential for PFAS risk assessment.

Exposure to per- and polyfluoroalkyl substances and age-related macular degeneration in U.S. middle-aged and older adults

Despite various health effects of per- and polyfluoroalkyl substances (PFAS) exposure, the association between PFAS exposure and age-related macular degeneration (AMD) has not been investigated. We aimed to assess associations of PFAS exposure with AMD, using data from 1722 U.S. adults aged 40 years or more participating in the National Health and Nutrition Examination Survey 2005–2008 with complete data on PFAS measurement, AMD diagnosis, and covariates. Serum concentrations of PFAS, including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS), were measured. An overall PFAS burden score was calculated using item response theory scoring. Individual PFAS concentration and overall PFAS burden score were categorized into low (reference), medium, and high groups. Diagnosis of AMD was based on retinal image examination. Any AMD was defined as the presence of early or late AMD. Survey-weighted logistic regression adjusted for potential confounders was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for presence of AMD according to PFAS exposure. Overall, 132 (6.5%) individuals were diagnosed as any AMD, including 115 (5.7%) individuals with early AMD. A significant dose-response association was observed between serum PFOS concentration and any AMD (p-trend = 0.03), with a significant OR of 1.99 (95% CI: 1.05, 3.79) for the high group compared to the reference. Overall PFAS burden showed a non-monotonic association with any AMD, with a significant OR of 2.18 (95% CI: 1.18, 4.04) for the medium. Inverted U-shaped associations were observed by restricted cubic spline analyses. Also, early AMD showed similar patterns in PFOS and overall PFAS burden and additionally an inverted U-shape association in PFNA. Our findings suggest that exposure to PFAS estimated by serum PFOS and PFNA as well as overall PFAS burden might be a risk factor for AMD in middle-aged and older population.

Current Challenges in Monitoring Low Contaminant Levels of Per- and Polyfluoroalkyl Substances in Water Matrices in the Field.

The Environmental Protection Agency (EPA) of the United States recently released the first-ever federal regulation on per- and polyfluoroalkyl substances (PFASs) for drinking water. While this represents an important landmark, it also brings about compliance challenges to the stakeholders in the drinking water industry as well as concerns to the general public. In this work, we address some of the most important challenges associated with measuring low concentrations of PFASs in drinking water in the field in real drinking water matrices. First, we review the "continuous monitoring for compliance" process laid out by the EPA and some of the associated hurdles. The process requires measuring, with some frequency, low concentrations (e.g., below 2 ppt or 2 ng/L) of targeted PFASs, in the presence of many other co-contaminants and in various conditions. Currently, this task can only (and it is expected to) be accomplished using specific protocols that rely on expensive, specialized, and laboratory-scale instrumentation, which adds time and increases cost. To potentially reduce the burden, portable, high-fidelity, low-cost, real-time PFAS sensors are desirable; however, the path to commercialization of some of the most promising technologies is confronted with many challenges, as well, and they are still at infant stages. Here, we provide insights related to those challenges based on results from ab initio and machine learning studies. These challenges are mainly due to the large amount and diversity of PFAS molecules and their multifunctional behaviors that depend strongly on the conditions of the media. The impetus of this work is to present relevant and timely insights to researchers and developers to accelerate the development of suitable PFAS monitoring systems. In addition, this work attempts to provide water system stakeholders, technicians, and even regulators guidelines to improve their strategies, which could ultimately translate in better services to the public.

Concentration and health risk assessment of per- and polyfluoroalkyl substances in cosmetic and personal care products

Per and polyfluoroalkyl substances (PFAS) are toxicologically concerning because of their potential to bioaccumulate and their persistence in the environment and the human body. We determined PFAS levels in cosmetic and personal care products and assessed their health risks. We investigated the trends in concentrations and types of PFAS contaminants in cosmetic and personal care products before and after perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were added to the list of persistent organic pollutants. The total PFAS concentration ranged from 1.98 to 706.75 ng g−1. The hazard quotients (HQs) for PFOA, PFOS and perfluorobutanesulfonic acid (PFBS) were lower than 1, indicating no appreciable risk to consumers. Assuming the simultaneous use of all product types and the worst-case scenario for calculations, perfluoroalkyl carboxylic acids and perfluoroalkane sulfonic acids (PFSAs) also had hazard indices lower than 1. We found that adverse effects are unlikely to occur when each type of cosmetic is used separately, or even when all product types are used together. Nevertheless, the persistence and bioaccumulation characteristics of additional PFAS present in cosmetics continue to be a cause for concern. Further research is necessary to investigate the long-term impacts of using such cosmetics and the associated risks to human health.

Contribution of Continued Dermal Exposure of PFAS-Containing Sunscreens to Internal Exposure: Extrapolation from In Vitro and In Vivo Tests to Physiologically Based Toxicokinetic Models.

Per- and polyfluoroalkyl substances (PFASs) are widely present in sunscreen products as either active ingredients or impurities. They may penetrate the human skin barrier and then pose potential health risks. Herein, we aimed to develop a physiologically based toxicokinetic (PBTK) model capable of predicting the body loading of PFASs after repeated, long-term dermal application of commercial sunscreens. Ten laboratory-prepared sunscreens, generally falling into two categories of water-in-oil (W/O) and oil-in-water (O/W) sunscreens, were subject to in vitro percutaneous penetration test to assess the impacts of four sunscreen ingredients on PFAS penetration. According to the results, two sunscreen formulas representing W/O and O/W types that mostly enhanced PFAS dermal absorption were then selected for a subsequent 30 day in vivo exposure experiment in mice. PBTK models were successfully established based on the time-dependent PFAS concentrations in mouse tissues (R2 = 0.885-0.947) and validated through another 30 day repeated exposure experiment in mice using two commercially available sunscreens containing PFASs (R2 = 0.809-0.835). The PBTK model results suggest that applying sunscreen of the same amount on a larger skin area is more conducive to PFAS permeation, thus enhancing the exposure risk. This emphasizes the need for caution in practical sunscreen application scenarios, particularly during the summer months.

Temporal trends of per- and polyfluoroalkyl substances concentrations: Insights from Australian human biomonitoring 2002–2021 and the U.S. NHANES programs 2003–2018

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorononanoic acid (PFNA) are persistent contaminants detected in human blood worldwide, raising significant health concerns. In response, countries such as the United States and Australia have implemented regulatory measures to limit their use. This study analysed temporal trends in serum concentrations of these four PFAS and how these trends align with regulatory measures, using data from NHANES (2003–2004 to 2017–2018) and the Australian Human Biomonitoring Program (2002–2003 to 2020–2021). Multiple regression analyses adjusted for age and gender were performed to estimate mean concentration changes over time, and differences within each dataset were assessed. Results indicated significant reductions (p < 0.001) in PFOS, PFOA, and PFHxS concentrations post-2002-2003, while PFNA concentrations increased until 2009–2010 before declining in both Australia and the U.S. Age-related trends in the U.S. during the last monitoring period showed higher PFAS concentrations in the oldest age groups, while in Australia, this trend was evident for PFOS and PFHxS. In Australia, the age group of 0–5 years had PFOA and PFNA concentrations similar to those of adults over 46 years, indicating ongoing exposure. Gender differences were consistent in both programs, with females aged 6–15, 31–45, and 46–60 years exhibiting lower serum concentrations, particularly in the 31–45 years age group. These findings support Australian and U.S. efforts to reduce PFAS exposure through regulatory actions, highlight the need to address ongoing exposure in young children, and consider gender-specific factors affecting PFAS concentrations.

Occurrence of perfluoroalkyl compounds in commercially available baby food produced in different European countries - levels, dietary intake, and exposure assessment

The presence of per- and polyfluoroalkyl substances (PFASs) in commercial baby food products from various European countries was investigated in this study. A total of 96 samples were collected and analyzed to assess PFASs levels, composition profiles, and potential dietary intake among infants. The results indicated detectable levels of PFASs in the sampled baby food products, with carboxylic acid prevalence over sulfonic acids. Among the various baby food groups studied, dry cereals exhibited the highest PFASs concentrations. This finding emphasizes the need for further monitoring and investigation of PFASs contamination in this specific food category. While the concentrations detected were generally low, they indicated the widespread presence of PFASs in various types of baby food. Furthermore, a preliminary exposure assessment was conducted on the basis of the measured PFASs concentrations, providing an initial insight into the potential exposure levels among infants from three months to three years old. Calculations based on two scenario types revealed the best-case scenario likely underestimating actual exposure, while the worst-case scenario occasionally exceeded the limits set by the governmental institutions. Further research is needed to understand the sources, pathways, and potential health effects of PFASs exposure in this vulnerable population.

Preferential Partitioning of Per- and Polyfluoroalkyl Substances in Freshwater Ice.

Millions of lakes worldwide freeze, yet the fate of per- and polyfluoroalkyl substances (PFAS) in ice in freshwater systems is poorly understood. We quantified concentrations of 36 PFAS, dissolved organic carbon (DOC), and inorganic ions in ice and water in seven freshwater lakes to investigate the preferential exclusion of ions during freezing. PFAS concentrations in ice are typically lower than in the water column, demonstrating that these chemicals are excluded from ice as it freezes. However, there is preferential partitioning of both PFAS and DOC relative to cations with average sodium-normalized enrichment factors (EF) ranging from 2.74 for perfluorobutanoate (PFBA; a C4 perfluorocarboxylic acid) to 4.01 for perfluorooctanesulfonate (PFOS; a C8 perfluorosulfonic acid), with a similar EF value of 4.14 for DOC. Laboratory experiments and seasonal measurements of PFAS in the water column indicate that PFAS concentrations in ice are a function of aqueous PFAS concentrations, with lower EF values observed in waters with higher PFAS concentrations. Understanding PFAS behavior in freshwater ice is important for predicting contaminant fate during winter and spring periods, with implications for exposure to PFAS during the winter and release of PFAS when ice melts in freshwater systems.

Spatial heterogeneity of per- and polyfluoroalkyl substances caused by glacial melting in Tibetan Lake Nam Co due to global warming

Per- and polyfluoroalkyl substances (PFASs) in high-latitude polar regions and the Tibetan Plateau have received widespread international attention. Here, we measured 18 PFASs and 11 major isomers in the lake water, sediment, and surrounding runoff of Lake Nam Co in 2020. The concentrations of ultrashort-chain trifluoroacetic acid (TFA) and perfluoropropanoic acid (PFPrA) and major isomers of perfluoooctanoic acid (PFOA) and perfluoooctane sulfonate acid (PFOS) in water bodies in high-latitude polar regions and the Tibetan Plateau are reported for the first time. The results showed that the concentration of ∑PFASs in glacial runoff was approximately 139 % greater than that in nonglacial runoff. The concentrations of ∑PFASs in the lake water and sediment in the southern lake with multiple glacial runoff events were approximately 113 % and 108 % higher, respectively, than those in the northern lake. The concentrations of short-chain perfluorobutanoic acid (PFBA) and ultrashort-chain TFA and PFPrA, which may be indicators of ice and snow melt, exhibited significant spatial heterogeneity. Overall, the spatial heterogeneity of PFAS concentrations in the water, sediment and surrounding runoff of Lake Nam Co may be caused mainly by glacial melting.

Examining a decade-long trend in exposure to per- and polyfluoroalkyl substances and their correlation with lipid profiles: Insights from a prospective cohort study on the young Taiwanese population

Per- and polyfluoroalkyl substances (PFAS) are artificial chemicals extensively utilized in everyday products, and numerous cross-sectional epidemiological studies consistently link PFAS exposure with lipid profiles across diverse populations and age groups. In longitudinal studies, the findings also indicate a positive correlation between PFAS and lipid profiles; however, this association remains unexplored in adolescents and young adults. Notably, previous research has predominantly focused on conventional lipid biomarkers, with limited exploration of the relationship between PFAS and diverse lipoprotein subfractions. Furthermore, there is a lack of comprehensive investigation into the temporal trends in PFAS concentrations in Taiwan. To address this research gap, we conducted a prospective study following 592 adolescents and young adults (12–30 years old at enrollment) from the YOung TAiwanese Cohort (YOTA) over a duration of 10 years. During the follow-up period, we measured 11 types of PFAS and various lipid profile biomarkers (low-density lipoprotein cholesterol (LDL-C), small dense LDL-C (sdLDL-C), low-density lipoprotein triglyceride (LDL-TG), high-density lipoprotein cholesterol (HDL-C), HDL3-C, lipoprotein(a), triglyceride). Our results revealed a general decline in PFAS concentrations in the study population. Regarding the correlation between the average levels (averaged across the initial and second tracking periods) of PFAS and lipid profiles (during the second tracking period), we observed positive correlations with total cholesterol and LDL-C for perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), N-methylperfluorooctane sulfonamide acetic acid (N-MeFOSAA), and the sum of PFAS (sum of the 11 kinds of PFAS). Additionally, average levels of PFUdA, N-MeFOSAA, and the sum of PFAS exhibited positive associations with sdLDL-C. This study unveiled an overall decrease in PFAS concentrations and underscores a potential link between PFAS exposure and adverse changes in lipid profiles among young populations, emphasizing the need for further exploration into the mechanisms of PFAS on lipid metabolism and atherosclerosis.

Phytoremediation Potential of Azolla filiculoides: Uptake and Toxicity of Seven Per- and Polyfluoroalkyl Substances (PFAS) at Environmentally Relevant Water Concentrations.

Environmental contamination of aquatic systems by per- and polyfluoroalkyl substances (PFAS) has generated significant health concerns. Remediation of contaminated sites such as the fire-fighting emergency training grounds that use aqueous film-forming foams is a high priority. Phytoremediation may help play a part in removing PFAS from such contaminated waters. We investigated the potential of the water fern Azolla filiculoides, which is used for phytoremediation of a wide range of contaminants, to uptake seven common PFAS (perfluorobutanoic acid [PFBA], perfluorobutane sulfonic acid [PFBS], perfluoroheptanoic acid [PFHpA], perfluorohexanoic acid [PFHxA], perfluorohexane sulfonic acid [PFHxS], perfluorooctanoic acid [PFOA], and perfluoropentanoic acid [PFPeA]), during a 12-day exposure to environmentally relevant concentrations delivered as equimolar mixtures: low (∑PFAS = 0.0123 ± 1.89 μmol L-1), medium (∑PFAS = 0.123 ± 2.88 μmol L-1), and high (∑PFAS = 1.39 μmol L-1) treatments, equivalent to approximately 5, 50, and 500 µg L-1 total PFAS, respectively. The possible phytotoxic effects of PFAS were measured at 3-day intervals using chlorophyll a content, photosystem II efficiency (Fv/Fm), performance index, and specific growth rate. The PFAS concentrations in plant tissue and water were also measured every 3 days using ultra-high-performance liquid chromatography-tandem mass spectrometry. Treatments with PFAS did not lead to any detectable phytotoxic effects. All seven PFAS were detected in plant tissue, with the greatest uptake occurring during the first 6 days of exposure. After 12 days of exposure, a maximum bioconcentration factor was recorded for PFBA of 1.30 and a minimum of 0.192 for PFBS. Consequently, the application of Azolla spp. as a stand-alone system for phytoremediation of PFAS in aquatic environments is not sufficient to substantially reduce PFAS concentrations. Environ Toxicol Chem 2024;00:1-12. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Drinking water quality impacts oocyte viability and embryo development.

Normal reproductive function and fertility is considered a "sixth vital sign" because disruptions to this sensitive physiological system can forewarn other health issues, including exposure to environmental toxicants. We found that female mice exhibited profound loss of embryos during pre-implantation and fetal development coincident with a change to the source of their drinking water. When female mice were provided with tap water from the building in which they were housed (Water 2), instead of tap water from a neighboring building which was their previous supply (Water 1), ovulated oocytes were degenerated or had impaired meiotic maturation, and failed to form embryos. The harmful effects of Water 2 exposure were not reversible even following a recovery period; however, carbon-filtration of Water 2 removed the toxic contaminant. Water composition analysis to identify the responsible toxicant(s) found that trace elements were present at expected levels and phthalates were undetectable. Per- and Poly-fluoroalkyl Substances (PFAS), a family of persistent organic pollutants were detected at ∼4 ng/L. To investigate further, female mice were given drinking water categorized by level of PFAS contamination (0.6 ng/L, 2.8 ng/L, or 4.4 ng/L) for 9 weeks. Compared to mice consuming purified MilliQ water, mice consuming PFAS-contaminated water had decreased oocyte quality, impaired embryogenesis and reduced cell numbers in blastocysts. PFAS concentration in the drinking water was negatively correlated with oocyte viability. Importantly, the levels of PFAS detected in the tap water are within current "safe level" guidelines, and further research is needed to determine whether PFAS are responsible for the observed reproductive toxicity. However, this research demonstrating that water deemed suitable for human consumption has detrimental effects on mammalian embryo development has important implications for public health and water quality policies.

On-site evaluation of DGT passive sampling for quantitatively measuring per- and polyfluoroalkyl substances in a river-estuary-sea water system

The passive sampling technique of diffusive gradients in thin-films (DGT) is promising for monitoring emerging contaminants such as per- and polyfluoroalkyl substances (PFAS). It is urgent to evaluate the impacts of salinity and exposure time on DGT sampling before it can be set as a standard method. Herein, DGT sampler based on the binding gel of weak anion exchanger (WAX) resin was deployed in a representative water system of the Xiaoqing river-estuary-sea for representative sampling windows (<1 day to 28 days) with high pH (8.18 ± 0.04 to 8.51 ± 0.17) and wide ranges of salinity (0.95 ± 0.07‰ to 14.37 ± 3.92‰), total dissolved solids (1.20 ± 0.09 g/L to 15.29 ± 3.91 g/L) and dissolved organic matter (2.8–32 mg/L). The results showed that the WAX-DGT sampler exhibited good performance for most target PFAS except for short-chain perfluorocarboxylates (C ≤ 5) in 14 days. When the exposure time was over 14 days, biofouling of the sampler may deflect the mass accumulation of the PFAS in the sampler. Salinity played an important role in the mass binding of PFAS by DGT. The shorter the carbon chain of the compound, the greater the influence of the salinity. PFAS with carboxyl groups had greater affinities for the biofouled membrane filter than those with sulfonic groups. In the river-estuary-sea system, where PFAS concentrations changed dynamically, the temporal resolution of the monitoring strategy has been demonstrated to be more important than spatial resolution. DGT provided a better integral of PFAS exposure than grab sampling in the dynamic water system and offered equivalent sensitivity of grab sampling with exposure time <10 d and greater sensitivity with exposure time ≥10 d. Thus, DGT has the advantage of providing high temporal resolution monitoring. This study provided support for the standardization of the DGT technique.

Occurrence, Concentration, and Distribution of 35 PFASs and Their Precursors Retained in 20 Stormwater Biofilters.

Current knowledge about the fate and transport behaviors of per- and polyfluoroalkyl substances (PFASs) in urban stormwater biofilter facilities is very limited. C5-14,16 perfluoroalkyl carboxylic acids [perfluorinated carboxylic acids (PFCAs)], C4,8,10 perfluoroalkanesulfonic acids (PFSAs), methyl-perfluorooctane sulfonamide acetic acid (MeFOSAA, a PFSA precursor), and unknown C6-8 PFCA and perfluorooctanesulfonic acid precursors were frequently found in bioretention media and forebay sediments at Σ35PFAS concentrations of <0.03-19 and 0.064-16 μg/kg-DW, respectively. Unknown C6-8 PFCA precursor concentrations were up to ten times higher than the corresponding PFCAs, especially at forebays and biofilters' top layer. No significant trend could be attributed to PFAS and precursor concentrations versus depth of filter media, though PFAS concentrations were 2-3 times higher in the upper layers on average (significant difference between the upper (0-5 cm) and deepest (35-50 cm) layer). PFASs had a similar spatial concentration distribution in each filter media (no clear difference between short- and long-chain PFASs). Commercial land use and organic matter were important factors explaining the concentration variations among the biofilters and between the sampling depths, respectively. Given the comparable PFAS accumulations in deeper and superficial layers and possible increased mobility after precursor biotransformation, designing shallow-depth, nonamended sand biofilters or maintaining only the top layer may be insufficient for stormwater PFAS management.

Comparison of surface freshwater PFAS sampling methods to evaluate potential for bias due to PFAS enrichment in the surface microlayer.

Per- and polyfluoroalkyl substances (PFAS) accumulate at the air-water interface of the surface microlayer (SML) on marine and freshwater bodies. In order to determine if including the SML when sampling bulk surface water leads to a high bias in measured PFAS concentrations, a pilot study and a full field study were conducted. The pilot study conducted at two sites was aimed at determining the analytical precision and small-scale (~1 m) spatial variability in concentrations of PFAS in bulk water and the SML. The full field study was performed at 11 sites, where three commonly used bulk surface water sampling methods were compared: (1) a peristaltic pump with tubing that excludes the SML, (2) a fully submerged sample bottle that excludes the SML, and (3) a partially submerged sample bottle that allows inclusion of the SML. The SML was sampled using the glass plate method. The samples were analyzed by liquid chromatography tandem mass spectrometry. The pilot study indicated that sampling variation was greater than analytical variation (although Levene's tests indicated that the differences were not statistically significant) and that relatively small differences in the mean concentration among sampling methods could be detected. The full investigation indicated that there was no evidence of high bias of PFAS concentrations in bulk surface water resulting from inclusion of SML using the partially submerged bottle sampling method. Unexpectedly, there was evidence that samples collected using the partially submerged bottle had slightly lower PFAS concentrations, particularly for less hydrophobic PFAS, than bulk water samples that excluded the SML. Additionally, the PFAS enrichment factor in the SML increased with increasing retention time, although the increase was not evident at all sampling sites for all PFAS. Integr Environ Assess Manag 2024;20:2271-2282. © 2024 SETAC.

Perfluoroalkyl functionalized-Au nanoparticle sensor: Employing rate of spectrum shifting for highly selective and sensitive detection of per- and polyfluoroalkyl substances (PFASs) in aqueous environments

Per- and polyfluoroalkyl substances (PFASs) are emerging contaminants detected ubiquitously and have negative impacts on human health and ecosystem; thus, developing in-situ sensing technique is important to ensure safety. Herein, we report a novel colorimetric-based sensor with perfluoroalkyl receptor attached to citrate coated gold nanoparticles (Citrate-Au NPs) that can detect several PFASs including perfluorocarboxylates with different chain lengths (PFHxA, PFOA, PFNA, PFDA), perfluorooctanoic sulfonate (PFOS), and perfluorooctanoic phosphonate (PFOPA). The sensor detects PFASs utilizing fluorous interaction between PFASs and the perfluoroalkyl receptor of Citrate-Au NPs in a solution at a fixed salt concentration, inducing changes in nanoparticle dispersity and the solution color. The rate of spectrum shift was linearly dependent on PFASs concentrations. Citrate-Au NPs with size between 29 – 109 nm were synthesized by adjusting citrate/Au molar ratios, and 78 nm showed the best sensitivity to PFOA concentration (with level of detection of 4.96 µM). Citrate-Au NPs only interacted with PFASs with perfluoroalkyl length > 4 and not with non-fluorinated alkyl compound (nonanoic acid). The performance of Citrate-Au NP based sensor was strongly dependent on the chain length of the perfluoroalkyl group and the head functional group; higher sensitivity was observed with longer chain over shorter chain, and with sulfonate functional group over carboxylate and phosphonate. The sensor was tested using real water samples (i.e., tap water, filtered river water), and it was found that the sensor is capable of detecting PFASs in these conditions if calibrated with the corresponding water matrix. While further optimization is needed, this study demonstrated new capability of Citrate-Au NPs based sensor for detection of PFASs in water.

Trophic fate and biomagnification of organic micropollutants from staple food to a specialized predator

The environmental burden of organic micropollutants has been shown in aquatic ecosystems, while trophic fate of many compounds in terrestrial food chains remains highly elusive. We therefore studied concentrations of 108 organic micropollutants in a common European mammal, the bank vole (Clethrionomys glareolus), and 82 of the compounds in a specialized predator, Tengmalm's owl (Aegolius funereus) relying to >90 % on voles as its prey. We studied compounds in whole voles (n = 19), pools of 4–8 bank voles (npools = 4), owl blood (n = 10) and in owl eggs (n = 10) in two regions in Sweden. For comparison, we also included previously published data on 23 PFAS (per- and polyfluoroalkyl substances) in bank vole liver (npools = 4) from the same regions. In voles, concentrations of the organic micropollutants caffeine (maxIndividual 220 ng/g ww) and DEET (N,N-diethyl-m-toluamide) (maxPool 150 ng/g ww) were 2–200 times higher in voles relative to owl blood and eggs. Conversely, concentrations of nicotine, oxazepam, salicylic acid, and tributyl citrate acetate were 1.3–440 times higher in owls. Several PFAS showed biomagnification in owls as revealed by maximum biomagnification factors (BMFs); PFNA (perfluorononanoate) BMF = 5.6, PFTeDA (perfluorotetradecanoic acid) BMF = 5.9, and PFOS (perfluorooctane sulfonate) BMF = 6.1. Concentrations of organic micropollutants, alongside calculated BMFs, and Tengmalm's owl's heavy reliance on bank vole as staple food, suggest, despite small sample size and potential spatio-temporal mismatch, accumulation of PFAS (especially PFNA, PFTeDA, and PFOS) in owls and biomagnification along the food chain. Concentrations of PFAS in owl eggs (e.g., 21 ng/g ww PFOS) highlight the likely pivotal role of maternal transfer in contaminant exposure for avian embryos. These concentrations are also of concern considering that certain predators frequently consume owl eggs, potentially leading to additional biomagnification of PFAS with yet undetermined consequences for ecosystem health.

Prenatal Exposure of PFAS in Cohorts of Pregnant Women: Identifying the Critical Windows of Vulnerability and Health Implications.

Cohorts of pregnant women in 2018 and 2020 were selected to explore prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFAS). Maternal serum during the whole pregnancy (first to third trimesters) and matched cord serum were collected for the analysis of 50 PFAS. Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and 6:2 fluorotelomer sulfonic acid (6:2 FTS) were the dominant PFAS in both the maternal and cord serum. The median ∑PFAS concentration was 14.18 ng/mL, and the ∑PFAS concentration was observed to decline from the first trimester to the third trimester. The transplacental transfer efficiencies (TTE) of 29 PFAS were comprehensively assessed, and a "U"-shaped trend in TTE values with increasing molecular chain length of perfluoroalkyl carboxylic acid (PFCA) was observed in this study. Moreover, the maternal concentrations of 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (6:2 Cl-PFESA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), PFOS, and hexafluoropropylene oxide dimer acid (HFPO-DA) in the 2020 cohort were significantly lower than those in the 2018 cohort, declining by about 23.85-43.2% from 2018 to 2020 (p < 0.05). Higher proportions of emerging PFAS were observed in fetuses born in 2020. This birth cohort was collected during the COVID-19 epidemic period. The change in the PFAS exposure scene might be in response to the different exposure profiles of the 2018 and 2020 cohorts, which are attributed to the impact of COVID-19 on the social activities and environment of pregnant women. Finally, by application of a multiple informant model, the third trimester was identified as the critical window of vulnerability to PFAS exposure that affects birth weight and birth length.