Protein-specific distribution patterns of perfluoroalkyl acids in egg yolk and albumen samples around a fluorochemical facility

Critical review: Considerations in applying avian egg injection studies to characterize effects of hydrophobic organic compounds on wild birds

Egg injection has been used for decades to determine embryonic mortality and developmental effects of chemical exposures in birds. Specific egg injection methods affect how well these studies replicate the process of chemical delivery to the embryo via maternal deposition, yet few data are available to compare exposure-response relationships between egg injection and maternal transfer studies. This information gap creates uncertainty when considering egg injection studies for assessment of potential adverse effects in wild birds. Focusing on hydrophobic organic compounds, we evaluated avian egg injection methods and potential methodological artifacts, through critical literature review and analyses of egg injection and maternal transfer data. Parameters that can affect embryotoxicity outcomes in egg injection studies include injection site, incubation orientation, type of vehicle, injection timing, injection volume, and different combinations of these parameters. Data to quantitatively compare embryotoxicity between egg injection and maternal transfer studies in the same species were identified only for a few polychlorinated biphenyl (PCB) mixtures and only for two egg injection methods, while comparisons among additional egg injection methods (without comparable maternal transfer toxicity data) were possible for certain PCB and dioxin congeners. Additionally, chemical uptake patterns in eggs and embryos were reviewed for different study designs. Overall, one egg injection study demonstrably replicated the exposure-response relationship from a comparable maternal transfer study, while median lethal doses (LD50s) varied up to 8-fold for the same congener across egg injection methods. Risk assessors should carefully consider the potential for over- or underestimation of toxicity when applying egg injection toxicity data during toxicity reference value development, and researchers should prioritize realistic representation of wild bird exposures when designing and standardizing egg injection protocols.

Contamination of the terrestrial food chain by per- and polyfluoroalkyl substances (PFAS) and related human health risks: A systematic review

BACKGROUND

PFAS contamination is a global issue, affecting various food sources, especially animal-based products like eggs and dairy.

OBJECTIVE

Collect scientific evidence of the presence of PFAS in diverse food and edible resources along with the related risks to human health, pursuing the following objectives: determination of the level of terrestrial food chain contamination; determination of the related human health risk.

DATA SOURCE

Scopus, PubMed, and Web of Science databases. 4952 papers published from January 2013 to August 2024 were retrieved and at the end of the selection process, 40 studies were included.

INCLUSION CRITERIA

Clear description of the methodology used for PFAS detection; relevance to food or species, or their parts, intended for human consumption; assessment of human health risk.

RESULTS

Higher number of studies were from China, 17, and Italy with 6 studies. The most detected PFAS were PFOA and PFOS. PFOS was detected at a maximum concentration of about 6 ng/g and 2.5 ng/g, in the edible muscles of cow and pork, respectively. Among animal products, eggs were the most contaminated with PFOA concentration higher than 100 ng/g. For PFBS and PFOS the maximum detected concentration ranged from about 35 ng/g up to about 45 ng/g. In vegetables, the highest number of per- and polyfluoroalkyl were detected in root, fruit, and leaf vegetables with maximum concentration up to about 60 ng/g as for PFBA. The highest Daily Intake (DI) values were detected in toddlers, whereas the lowest in the adult population. Concerning total diet, DI related to total PFAS ranged from about 30 (ng/kg bw/day) up to about 90 (ng/kg bw/day).

CONCLUSIONS

The widespread presence and health risks of PFAS, along with the need for new strategies to reduce contamination in food chains, were emphasized. Gaps in legislation and limits of PFAS detection methods were also noted.

Differentiated distribution between albumen, yolk and eggshell of parents and metabolites neonicotinoids and their reproductive exposure risk

Differential distribution of neonicotinoids (NEOs) in albumen, yolk, and eggshell is a critical factor influencing their bio-accumulative behavior and the subsequent human health risks. However, there is currently no relevant research available. We collected 62 egg samples from 31 sampling sites across China and analyzed the concentrations and characteristics of 12 parents NEOs (p-NEOs) and 8 metabolites NEOs (m-NEOs) in albumen, yolk, and eggshell. NEOs were frequently detected in differentiated egg matrices, with the highest concentrations observed in Northeast China. The concentrations of m-NEOs were generally higher than those of p-NEOs. A positive correlation was found between the distribution of m-NEOs in albumen and their logKow (p < 0.05). Dietary intake exposure posed a higher risk of NEOs to children and females. The toxicity equivalence (TEQ) of 5-hydroxy-imidacloprid and thiacloprid-amide, in interaction with androgen and estrogen receptors, was higher compared to other NEOs. Network toxicology and molecular docking indicated that AKT1 may serve as the core target for reproductive toxicity induced by dinotefuran, cycloxaprid, and nitenpyram exposure. This study provided valuable data on the occurrence, differential distribution, and reproductive exposure risk of NEOs in eggs for the first time. These findings are instrumental for future management policies concerning the environmental behavior and health effects of NEOs.

Dynamic spatiotemporal changes of per- and polyfluoroalkyl substances (PFAS) in soil and eggs of private gardens at different distances from a fluorochemical plant

Homegrown food serves as an important human exposure source of per- and polyfluoroalkyl substances (PFAS), yet little is known about their spatiotemporal distribution within and among private gardens. This knowledge is essential for more accurate site-specific risk assessment, identification of new sources and evaluating the effectiveness of regulations. The present study evaluated spatiotemporal changes of legacy and emerging PFAS in surface soil from vegetable gardens (N = 78) and chicken enclosures (N = 102), as well as in homegrown eggs (N = 134) of private gardens, across the Province of Antwerp (Belgium). Hereby, the potential influence of the wind orientation and distance towards a major fluorochemical plant was examined. The ∑short-chain PFAS and precursor concentrations were higher in vegetable garden soil (8.68 ng/g dry weight (dw)) compared to chicken enclosure soil (4.43 ng/g dw) and homegrown eggs (0.77 ng/g wet weight (ww)), while long-chain sulfonates and C11-14 carboxylates showed the opposite trend. Short-term (2018/2019-2022) changes were mostly absent in vegetable garden soil, while changes in chicken enclosure soils oriented S-SW nearby (<4 km) the fluorochemical plant were characterized by a local, high-concentration plume. Moreover, soil from chicken enclosures oriented SE and remotely from the plant site was characterized by a widespread, diffuse but relatively low-concentration plume. Long-term data (2010-2022) suggest that phaseout and regulatory measures have been effective, as PFOS concentrations nearby the fluorochemical plant in soil and eggs have declined from 25.8 to 2.86 ng/g dw and from 528 to 39.4 ng/g ww, respectively. However, PFOS and PFOA concentrations have remained largely stable within this timeframe in gardens remotely from the plant site, warranting further rapid regulation and remediation measures. Future monitoring efforts are needed to allow long-term comparison for multiple PFAS and better distinction from potential confounding variables, such as variable emission outputs and variability in wind patterns.

Characterizing Important Dietary Exposure Sources of Perfluoroalkyl Acids in Inuit Youth and Adults in Nunavik Using a Feature Selection Tool

BACKGROUND

Previous studies have identified the consumption of country foods (hunted/harvested foods from the land) as the primary exposure source of perfluoroalkyl acids (PFAA) in Arctic communities. However, identifying the specific foods associated with PFAA exposures is complicated due to correlation between country foods that are commonly consumed together.

METHODS

We used venous blood sample data and food frequency questionnaire data from the Qanuilirpitaa? ("How are we now?") 2017 (Q2017) survey of Inuit individuals ≥ 16 y of age residing in Nunavik (n = 1,193 ). Adaptive elastic net, a machine learning technique, identified the most important food items for predicting PFAA biomarker levels while accounting for the correlation among the food items. We used generalized linear regression models to quantify the association between the most predictive food items and six plasma PFAA biomarker levels. The estimates were converted to percent changes in a specific PFAA biomarker level per standard deviation increase in the consumption of a food item. Models were also stratified by food type (market or country foods).

RESULTS

Perfluorooctanesulfonic acid (PFOS), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were associated with frequent consumption of beluga misirak (rendered fat) [14.6%; 95% confidence interval (CI): 10.3%, 18.9%; 14.6% (95% CI: 10.1%, 19.0%)], seal liver [9.3% (95% CI: 5.0%, 13.7%); 8.1% (95% CI: 3.5%, 12.6%)], and suuvalik (fish roe mixed with berries and fat) [6.0% (95% CI: 1.3%, 10.7%); 7.5% (95% CI: 2.7%, 12.3%)]. Beluga misirak was also associated with higher concentrations of perfluorohexanesulphonic acid (PFHxS) and perfluorononanoic acid (PFNA), albeit with lower percentage changes. PFHxS, perfluorooctanoic acid (PFOA), and PFNA followed some similar patterns, with higher levels associated with frequent consumption of ptarmigan [6.1% (95% CI: 3.2%, 9.0%); 5.1% (95% CI: 1.1%, 9.1%); 5.4% (95% CI: 1.8%, 9.0%)]. Among market foods, frequent consumption of processed meat and popcorn was consistently associated with lower PFAA exposure.

CONCLUSIONS

Our study identifies specific food items contributing to environmental contaminant exposure in Indigenous or small communities relying on local subsistence foods using adaptive elastic net to prioritize responses from a complex food frequency questionnaire. In Nunavik, higher PFAA biomarker levels were primarily related to increased consumption of country foods, particularly beluga misirak, seal liver, suuvalik, and ptarmigan. Our results support policies regulating PFAA production and use to limit the contamination of Arctic species through long-range transport. https://doi.org/10.1289/EHP13556.

Per- and poly-fluoroalkyl substances in commercial organic eggs via fishmeal in feed

Chicken eggs can be a significant source of human PFAS exposure. A survey of PFAS in commercial eggs from larger farms across Denmark showed the absence or low contents of PFAS in free-range and barn eggs. However, organic eggs from eight farms collected in September 2022 had a similar profile of nine PFASs with a predominance of odd over even carbon length PFCAs. Farm 11-13 e.g. had egg yolk ng/g concentrations of PFOA 0.07 ± 0.02; PFNA 0.37 ± 0.04; PFDA 0.13 ± 0.00; PFUnDA 0.22 ± 0.04; PFDoDA 0.06 ± 0.02; PFTrDA 0.15 ± 0.04; PFTeDA 0.02 ± 0.02; PFHxS 0.10 ± 0.04; PFOS 2.62 ± 0.11. Normalised to PFOS, the relative sum of other PFAS showed no difference between the eight organic egg samples, but significant differences between mean individual PFASs (p = 1.4E-25), reflecting a similar profile. The PFAS found in two fishmeal samples with the same origin as the fishmeal used for the organic feed production, could account for the contents in the eggs via estimated transfer from the feed. Furthermore, the estimated transfer from concentration in feed to concentration in egg increased with the carbon length of the PFCA. Exposure (95th percentile) of ∑4PFAS (PFOA, PFNA, PFHxS, PFOS) solely from consumption of 311 g ∼ 5-6 organic eggs/week was for children 4-9 years 10.4 ng/kg bw, i.e. a significant exceedance of the tolerable weekly intake of 4.4 ng/kg bw established by the European Food Safety Authority. Based on the PFAS exposures from organic egg consumption, the organic egg producers decided voluntarily to cease adding fishmeal to the feed. Since the feed-to-egg half-lives are ≤1 week for PFOA, PFOS, and PFHxS, the removal of fishmeal as a feed ingredient should eliminate PFAS after 1-2 months. This was demonstrated in analyses of ten organic egg samples collected by the authorities without PFAS in eight and with 0.1 and 0.4 ng/g ∑4PFAS in two samples.

Bioaccumulation, tissue distributions, and maternal transfer of perfluoroalkyl carboxylates (PFCAs) in laying hens

Laying hens were exposed to feeds spiked with a series of perfluoroalkyl carboxylates (PFCAs) ranging from perfluorobutanoic acid (C4) to perfluorooctadecanoic acid (C18) to investigate their bioaccumulation, tissue distribution, and maternal transfer. We found that PFCAs with longer carbon chains (>8) were more efficiently absorbed in the gastrointestinal tract than those with shorter chains (≤8), and that the rate of depuration varied inversely with the carbon chain length in a U-shaped pattern. Moreover, bioaccumulation potential increased with increasing carbon-chain length, except for C4. Distinct affinities were observed for specific carbon-chain PFCAs across various tissues, evident from their differential accumulation during both uptake and depuration phases. Specifically, C9 showed a higher affinity for serum and liver, C12 was more prevalent in yolk, C14 was notably abundant in the brain, and C18 was predominant in other tissues. Furthermore, the egg-maternal ratio (EMR) increased with increasing carbon-chain length from C7 to C11 and reached a plateau phase for C12 to C18. Our study also confirmed the key role of phospholipids in the tissue distribution and maternal transfer of long-chain PFCAs. This study sheds light on the interaction between PFCAs and biological tissues and reveals the toxicokinetic factors that influence the bioaccumulation of PFCAs. Further research is needed to identify the specific proteins or components that mediate the tissue-specific affinity for different carbon-chain lengths of PFCAs.

Analytical methods employed in the identification and quantification of per- and polyfluoroalkyl substances in human matrices - A scoping review

Persistent organic pollutants (POPs) represent a possible hazard for the ecosystems, with adverse outcomes on wildlife and humans. POPs have always received interest from the scientific community, and they have also been subject to legal restrictions worldwide on their application and commercialization. Among the broad spectrum of POPs, per- and polyfluoroalkyl substances (PFASs) are considered emerging contaminants due to their potential effect on the ecosystem and human health. These contaminants are widely employed in countless applications, from surfactants and building materials to food packaging. On the other hand, their chemical structure gives them the ability to interact with the environment, causing possible toxic effects for humans and environment. Human biomonitoring is a necessary instrument to indagate the impact of PFASs on human health: in recent years several studies have found detectable levels of PFASs in several biological matrices in humans (blood, hair, nails, and urine). Here, we review the most recent scientific literature concerning analytical methods employed in the identification and quantification of PFASs focusing on biological matrices. It has been noted that liquid chromatography coupled with mass spectrometry is the main analytical instrumentation employed, while blood and/or serum samples are the main employed human matrices whereas the use of non-invasive matrices is still at the beginning. Various issues directly related to human metabolism of PFASs and the effective amount of PFAS absorbed from the environment still need to be investigated.

Prediction of perfluoroalkyl acids (PFAAs) in homegrown eggs: Insights into abiotic and biotic factors affecting bioavailability and derivation of potential remediation measures

Homegrown eggs from free-ranging laying hens often contain elevated concentrations of perfluoroalkyl acids (PFAAs). However, it is unclear which factors contribute to these relatively large exposure risk scenarios. Moreover, existing bioavailability and modeling concepts of conventional organic pollutants cannot be generalized to PFAAs due to their different physicochemical soil interactions. Therefore, there is an urgent need for empirical models, based on real-world data, to provide insights into how (a)biotic factors affect the bioavailability to eggs. To this end, 17 targeted analytes were analyzed in abiotic (i.e. rainwater, soil; both N = 101) matrices and homegrown eggs (N = 101), which were sampled in 101 private gardens across Flanders (Belgium) in 2019, 2021 and 2022. Various soil characteristics were measured to evaluate their role in affecting PFAA bioavailability to the eggs. Finally, PFAAs were measured in potential feed sources (i.e. homegrown vegetable and earthworm pools; respectively N = 49 and N = 34) of the laying hens to evaluate their contribution to the egg burden. Modeling suggested that soil was a major exposure source to laying hens, accounting for 16-55% of the total variation in egg concentrations for dominant PFAAs. Moreover, concentrations in vegetables and earthworms for PFBA and PFOS, respectively, were significantly positively related with corresponding egg concentrations. Predictive models based on soil concentrations, total organic carbon (TOC), pH, clay content and exchangeable cations were successfully developed for major PFAAs, providing possibilities for time- and cost-effective risk assessment of PFAAs in homegrown eggs. Among other soil characteristics, TOC and clay content were related with lower and higher egg concentrations for most PFAAs, respectively. This suggests that bioavailability of PFAAs to the eggs is driven by complex physicochemical interactions of PFAAs with TOC and clay. Finally, remediation measures were formulated that are readily applicable to lower PFAA exposure via homegrown eggs.

Current Review of Increasing Animal Health Threat of Per- and Polyfluoroalkyl Substances (PFAS): Harms, Limitations, and Alternatives to Manage Their Toxicity

Perfluorinated and polyfluorinated alkyl substances (PFAS), more than 4700 in number, are a group of widely used man-made chemicals that accumulate in living things and the environment over time. They are known as "forever chemicals" because they are extremely persistent in our environment and body. Because PFAS have been widely used for many decades, their presence is evident globally, and their persistence and potential toxicity create concern for animals, humans and environmental health. They can have multiple adverse health effects, such as liver damage, thyroid disease, obesity, fertility problems, and cancer. The most significant source of living exposure to PFAS is dietary intake (food and water), but given massive industrial and domestic use, these substances are now punctually present not only domestically but also in the outdoor environment. For example, livestock and wildlife can be exposed to PFAS through contaminated water, soil, substrate, air, or food. In this review, we have analyzed and exposed the characteristics of PFAS and their various uses and reported data on their presence in the environment, from industrialized to less populated areas. In several areas of the planet, even in areas far from large population centers, the presence of PFAS was confirmed, both in marine and terrestrial animals (organisms). Among the most common PFAS identified are undoubtedly perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), two of the most widely used and, to date, among the most studied in terms of toxicokinetics and toxicodynamics. The objective of this review is to provide insights into the toxic potential of PFAS, their exposure, and related mechanisms.

Dietary and maternal sociodemographic determinants of perfluoroalkyl and polyfluoroalkyl substance levels in pregnant women

Diet, including drinking water, and demographic characteristics have been associated with PFAS exposure levels in the general population. But data in pregnant women are scarce. We aimed to examine the PFAS levels in relation to these factors in early pregnancy and included 2545 pregnant women in early pregnancy from the Shanghai Birth Cohort. Ten PFAS were measured using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS-MS) in plasma samples at around 14 weeks of gestation. Geometric mean (GM) ratios were used to estimate the associations between demographic characteristics, food intake and source of drinking water and concentrations of nine PFAS with a detection rate of at least 70%, and the total perfluoroalkyl carboxylic acids (∑PFCA), perfluoroalkyl sulfonic acids (∑PFSA) and all the PFAS concentrations (∑PFAS). Median concentrations of plasma PFAS ranged from 0.03 ng/mL for PFBS to 11.56 ng/mL for PFOA. In the multivariable linear models, maternal age, parity, parental education level, marine fish, freshwater fish, shellfish, shrimps, crabs, animal kidneys, animal liver, eggs, and bone soup in early pregnancy were positively associated with plasma concentrations of certain PFAS. Whereas pre-pregnancy BMI, plant-based foods, and drinking bottled water were negatively associated with some PFAS concentrations. In summary, this study suggested that fish and seafood, animal offal, and high-fat foods (eggs and bone soup) were significant sources of PFAS. PFAS exposure may be reduced by consuming more plant-based foods and potential interventions, such as drinking water treatment.

Global ocean contamination of per- and polyfluoroalkyl substances: A review of seabird exposure

Per- and polyfluoroalkyl substances (PFAS) have been extensively produced and used as surfactants and repellents for decades. To date, the global contamination pattern of PFAS in marine biota has seldomly been reviewed. Seabirds are ideal biomonitoring tools to study environmental contaminants and their effects. Here, we compiled and synthesized reported PFAS concentrations in various seabird species to reflect spatiotemporal patterns and exposure risks of major PFAS on a global ocean scale. Perfluorooctane sulfonic acid (PFOS) was the most studied PFAS in seabirds, which showed the highest level in eggs of common guillemots (U. aalge) from the Baltic Sea, followed by great cormorants (P. carbo) from the North Sea and double-crested cormorants (P.auritus) from the San Francisco Bay, whereas the lowest were those reported for Antarctic seabirds. The temporal pattern showed an overall higher level of PFOS in the late 1990s and early 2000s, consistent with the phase-out of perfluorooctane sulfonyl fluoride-based products. Maximum liver PFOS concentrations in several species such as cormorants and fulmars from Europe and North America exceeded the estimated toxicity reference values. Systematic evaluations using representative species and long time-series are necessary to understand contamination patterns in seabirds in South America, Africa, and Asia where information is lacking. In addition, limited research has been conducted on the identification and toxic effects of novel substitutes such as fluorotelomers and ether PFAS (F-53B, Gen-X etc.) in seabirds. Further research, including multi-omics analysis, is needed to comprehensively characterize the exposure and toxicological profiles of PFAS in seabirds and other wildlife.

Isomer-specific perfluoroalkyl acids accumulation, excretion and maternal transfer to eggs in chickens around a fluorochemical manufactory in China

The co-existing of multiple Per- and polyfluoroalkyl substances (PFASs) might pose more complicated situation for the exposure risk of environment and biota, especially for the surrounding area of the contaminated communities. In this study, tissues and organs of free-ranged chickens, paired eggs, corresponding feces, water, soil/dust, and feed samples around a fluorochemical manufactory were collected to investigate the tissue-isomer-specific accumulation, elimination and maternal transfer to eggs of PFASs. Free-ranged chickens had much higher ∑PFASs concentrations than farm chickens, and PFBA and PFOS were the predominant PFASs in tissues and organs, which is consistence with the electrochemical fluorination (ECF) production pattern of this manufactory. This result implied that PFASs released from manufactory production is a direct exposure source to the chickens. ∑PFASs concentrations in yolk samples were higher than other tissues and organs, while the concentrations in albumen were lowest. Isomer profiles analysis indicated that n-PFOS proportions in tissues, organs, yolk, and albumen ranged from 85.3 %-98.1 %, whereas in the feces with the percentage of 72.9 %, indicating that the branched PFOS isomers showed faster excretion rate than n-PFOS for chickens. Resident's estimated daily intakes (EDIs) of ∑PFASs via chicken were in the range of 6.41 to 107.18 ng/kg·bw/d. Notably, the EDIs of the sum of four PFASs were higher than the TDI of EFSA in 2020, indicating potential health risks.

Home-produced eggs: An important human exposure pathway of perfluoroalkylated substances (PFAS)

Humans are generally exposed to per- and polyfluoroalkyl substances (PFAS) through their diet. Whilst plenty of data are available on commercial food products, little information exists on the contribution of self-cultivated food, such as home-produced eggs (HPE), to the dietary PFAS intake in humans. The prevalence of 17 legacy and emerging PFAS in HPE (N = 70) from free-ranging laying hens was examined at 35 private gardens, situated within a 10 km radius from a fluorochemical plant in Antwerp (Belgium). Potential influences from housing conditions (feed type and number of individuals) and age of the chickens on the egg concentrations was examined, and possible human health risks were evaluated. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were detected in all samples. PFOS was the dominant compound and concentrations (range: 0.13-241 ng/g wet weight) steeply decreased with distance from the fluorochemical plant, while there was no clear distance trend for other PFAS. Laying hens receiving an obligate diet of kitchen leftovers, exhibited higher PFOS and PFOA concentrations in their eggs than hens feeding only on commercial food, suggesting that garden produce may be a relevant exposure pathway to both chickens and humans. The age of laying hens affected egg PFAS concentrations, with younger hens exhibiting significantly higher egg PFOA concentrations. Based on a modest human consumption scenario of two eggs per week, the European health guideline was exceeded in ≥67% of the locations for all age classes, both nearby and further away (till 10 km) from the plant site. These results indicate that PFAS exposure via HPE causes potential human health risks. Extensive analysis in other self-cultivated food items on a larger spatial scale is highly recommended, taking into account potential factors that may affect PFAS bioavailability to garden produce.

Fast and Sensitive Analysis of Short- and Long-Chain Perfluoroalkyl Substances in Foods of Animal Origin

The availability of sensitive analytical methods to detect per- and polyfluoroalkyl substances (PFASs) in food of animal origin is fundamental for monitoring programs to collect data useful for improving risk assessment strategies. The present study aimed to develop and validate a fast and sensitive method for determining short and long-chain PFASs in meat (bovine, fish, and swine muscle), bovine liver, hen eggs, and cow’s milk to be easily applicable in routine analysis of food. A QuEChERS extraction and clean-up method in combination with liquid chromatography coupled to mass spectrometry (LC-MSMS) were used. The method resulted in good linearity (Pearson’s R > 0.99), low limits of detection (7.78−16.35 ng/kg, 8.26−34.01 ng/kg, 6.70−33.65 ng/kg, and 5.92−19.07 ng/kg for milk, liver, egg, and muscle, respectively), and appropriate limits of quantification (50 ng/kg for all compounds except for GenX and C6O4, where the limits of quantification were 100 ng/kg). Trueness and precision for all the tested levels met the acceptability criteria of 80−120% and ≤20%, respectively, regardless of the analyzed matrix. As to measurement uncertainty, it was <50% for all compound/matrix combinations. These results demonstrate the selectivity and sensitivity of the method for simultaneous trace detection and quantification of 14 PFASs in foods of animal origin, verified through the analysis of 63 food samples.

Perfluoroalkylated compounds in the eggs and feathers of resident and migratory seabirds from the Antarctic Peninsula

In this study, we investigated factors that influence the differences in exposure of perfluoroalkyl acids (PFAAs) from eight species of Antarctic seabirds, including Pygoscelis penguins, Stercorarius maccormicki, and Macronectes giganteus. We analyzed the relationship between foraging ecology (based on δ¹³C, δ¹⁵N, and δ³⁴S values) and PFAAs accumulated in eggs and breast feathers. Ten out of 15 targeted PFAAs were detected in eggs compared to eight in feathers. Mean ∑PFAA concentrations in feathers ranged from 0.47 in P. antarcticus to 17.4 ng/g dry weight (dw) in S. maccormicki. In eggs, ∑PFAA concentrations ranged from 3.51 in P. adeliae to 117 ng/g dw in S. maccormicki. The highest concentrations of most PFAAs were found in trans-equatorial migrators such as S. maccormicki, probably due their high trophic position and higher concentrations of PFAAs in the Northern Hemisphere compared to the Southern Hemisphere. Based on stable isotopes correlations, our results suggest that the trophic position (δ¹⁵N) and the foraging area (δ¹³C and δ³⁴S) influence PFAAs concentrations in Antarctic seabirds. Our results point to the possibility that long-distance migratory birds may have as bio-vectors in the transport of pollutants, including PFCAs, in Antarctic environments, although this must be further confirmed in future studies using a mass balanced approach, such as extractable organofluorine (EOF).

Healthy eating index and diet diversity score as determinants of serum perfluoroalkyl acid (PFAA) concentrations in a national survey of Swedish adolescents

Food is an important source of perfluoroalkyl acid (PFAA) exposure for the general adult population, but few data exist for adolescents. Healthy food habits established during adolescence may positively influence health later in life. Associations between serum PFAA concentrations and a healthy eating index (SHEIA15), as well as a diet diversity score (RADDS), were determined in a nationally representative adolescent population from Sweden (Riksmaten Adolescents 2016-2017, RMA). Using consumption data from food registrations and frequency questionnaires, we additionally analyzed associations with commonly consumed food groups. Associations were analyzed by fitting a cumulative probability model using ordinal regression. Among the seven PFAAs detected in ≥70% of the 1098 participants (age 10-21 years), median concentrations ranged from <1 ng/g serum of perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perflurorundecanoic acid (PFUnDA), linear (lin-) perfluorohexanesulfonic acid (PFHxS) and branched (br-) perfluorooctanesulfonic acid (PFOS) to 1-2 ng/g serum of lin-perfluorooctanoic acid (PFOA) and lin-PFOS. PFNA, PFDA, PFUnDA and lin-PFOS concentrations were positively associated with both SHEIA15 and RADDS, a finding most likely driven by higher consumption of seafood. PFDA, PFUnDA and lin-PFOS concentrations were positively related to commonly consumed fish/shellfish groups, such as lean marine fish and shellfish. Inverse associations between PFAA concentrations and dairy consumption suggest an underlying factor behind dairy consumption that similarly affects adolescent exposure to the different PFAAs. Isomeric differences in dietary exposure between lin-PFOS and br-PFOS were suggested, as br-PFOS concentrations, in contrast to lin-PFOS, were not associated with SHEIA15, RADDS and consumption of different food groups. We conclude that Swedish adolescents, adhering to a diverse and healthy diet, appears to be more highly exposed to legacy PFAAs than those eating less healthy. Additional research is necessary for a better understanding of the health implications of healthy eating from a PFAA exposure perspective.

A Bad Start in Life? Maternal Transfer of Legacy and Emerging Poly- and Perfluoroalkyl Substances to Eggs in an Arctic Seabird

In birds, maternal transfer is a major exposure route for several contaminants, including poly- and perfluoroalkyl substances (PFAS). Little is known, however, about the extent of the transfer of the different PFAS compounds to the eggs, especially for alternative fluorinated compounds. In the present study, we measured legacy and emerging PFAS, including Gen-X, ADONA, and F-53B, in the plasma of prelaying black-legged kittiwake females breeding in Svalbard and the yolk of their eggs. We aimed to (1) describe the contaminant levels and patterns in both females and eggs, and (2) investigate the maternal transfer, that is, biological variables and the relationship between the females and their eggs for each compound. Contamination of both females and eggs were dominated by linPFOS then PFUnA or PFTriA. We notably found 7:3 fluorotelomer carboxylic acid─a precursor of long-chain carboxylates─in 84% of the egg yolks, and provide the first documented finding of ADONA in wildlife. Emerging compounds were all below the detection limit in female plasma. There was a linear association between females and eggs for most of the PFAS. Analyses of maternal transfer ratios in females and eggs suggest that the transfer is increasing with PFAS carbon chain length, therefore the longest chain perfluoroalkyl carboxylic acids (PFCAs) were preferentially transferred to the eggs. The mean ∑_PFAS in the second-laid eggs was 73% of that in the first-laid eggs. Additional effort on assessing the outcome of maternal transfers on avian development physiology is essential, especially for PFCAs and emerging fluorinated compounds which are under-represented in experimental studies.

Understanding the dynamics of physiological changes, protein expression, and PFAS in wildlife

Per- and polyfluoroalkyl substances (PFAS) accumulation and elimination in both wildlife and humans is largely attributed to PFAS interactions with proteins, including but not limited to organic anion transporters (OATs), fatty acid binding proteins (FABPs), and serum proteins such as albumin. In wildlife, changes in the biotic and abiotic environment (e.g. salinity, temperature, reproductive stage, and health status) often lead to dynamic and responsive physiological changes that alter the prevalence and location of many proteins, including PFAS-related proteins. Therefore, we hypothesize that if key PFAS-related proteins are impacted as a result of environmentally induced as well as biologically programmed physiological changes (e.g. reproduction), then PFAS that associate with those proteins will also be impacted. Changes in tissue distribution across tissues of PFAS due to these dynamics may have implications for wildlife studies where these chemicals are measured in biological matrices (e.g., serum, feathers, eggs). For example, failure to account for factors contributing to PFAS variability in a tissue may result in exposure misclassification as measured concentrations may not reflect average exposure levels. The goal of this review is to share general information with the PFAS research community on what biotic and abiotic changes might be important to consider when designing and interpreting a biomonitoring or an ecotoxicity based wildlife study. This review will also draw on parallels from the epidemiological discipline to improve study design in wildlife research. Overall, understanding these connections between biotic and abiotic environments, dynamic protein levels, PFAS levels measured in wildlife, and epidemiology serves to strengthen study design and study interpretation and thus strengthen conclusions derived from wildlife studies for years to come.

Species- and Tissue-Specific Chronic Toxicity Values for Northern Bobwhite Quail (Colinus virginianus) Exposed to Perfluorohexane Sulfonic Acid and a Binary Mixture of Perfluorooctane Sulfonic Acid and Perfluorohexane Sulfonic Acid

Per- and polyfluoroalkyl substances (PFAS) are globally distributed and present in nearly every environmental compartment. Characterizing the chronic toxicity of individual PFAS compounds and mixtures is necessary because many have been reported to cause adverse health effects. To derive toxicity reference values (TRVs) and conduct ecotoxicological risk assessments (ERAs) of PFAS-contaminated ecosystems for wildlife, species-specific PFAS chronic toxicity values (CTVs) are needed. The present study quantified PFAS residues from liver and eggs of birds chronically exposed to perfluorohexanoic acid (PFHxA) or a mixture of perfluorooctane sulfonate (PFOS) and PFHxA that produced a no-observable-adverse-effect level (NOAEL) and/or a lowest-observable-adverse-effectlevel (LOAEL). The CTVs we present are lower than those previously reported for birds and should be considered in future regulatory evaluations. From the estimated species- and tissue-specific PFAS CTVs, we found that PFOS and perfluorohexane sulfonate (PFHxS) were more bioaccumulative than PFHxA in avian tissues, but PFHxA was more toxic to reproducing birds than either PFOS or a PFOS:PFHxS mixture. We further determined that avian toxicity was not necessarily additive with respect to PFAS mixtures, which could have implications for PFAS ERAs. The PFAS LOAEL CTVs can be used to predict reproductive and possible population-level adverse health effects in wild avian receptors. Environ Toxicol Chem 2022;41:219-229. © 2021 SETAC.

Levels and trends of perfluoroalkyl acids (PFAAs) in water (2013-2020) and fish from selected riverine basins in Spain

The aim of the present study was to assess the presence of perfluoroalkyl acids (PFAAs), namely perfluoroalkane sulfonates and perfluoroalkyl carboxylic acids, in Spanish river basins in order to: identify potential spatiotemporal variations; evaluate the effectiveness of the measures implemented for the reduction/elimination of these pollutants; verify the fulfillment of the Environmental Quality Standards (EQSs) in the European Union. PFOS and PFOA were determined in 116 water samples from four sites in the Duero basin, the largest in the Iberian Peninsula, collected seasonally from 2013 to 2020. In addition, 30 fish sample composites from the sample banks of Duero, Tagus, Ebro, Eastern Cantabrian and Catalonian basins were analyzed for 15 PFAAs. Median PFOS and PFOA concentrations were 0.72 and 0.42 ng/L, ranging from values below the limit of quantification (LOQ) to 81 and 22 ng/L, respectively. During the studied period, 51% of water samples were above the EQS of 0.65 ng/L for PFOS. In the case of fish, the PFOS range was <LOQ-59 with 33% of the samples above the EQS of 9.1 ng/g wet weight. Moreover, fish from the Tagus and Catalonian basins showed median concentrations above the EQS. Particularly, fish collected around highly populated areas such as Madrid and Barcelona showed the greatest PFAA concentrations. Overall, PFAA concentrations in water and fish increased significantly with population density suggesting urban areas as their main source. Although our results suggested decreasing tendencies for PFOS and PFOA in water, significant trends only could be confirmed at two sampling sites.

Fabrication of a near-infrared excitation surface molecular imprinting ratiometric fluorescent probe for sensitive and rapid detecting perfluorooctane sulfonate in complex matrix

Construction of fluorescent probe for highly sensitive and selective detection of perfluorooctane sulfonate (PFOS) in water and biological samples is a very important strategy in related pollutant monitoring and environmental health risk appraisal. To overcome the drawback of low sensitivity caused by high-back ground signal of the conventional sensor, a molecularly imprinted near-infrared excitation ratiometric fluorescent probe was constructed and employed to determine PFOS. The sensing process was achieved through the selectively recognition of specific cavities in the probe surface with analyte, accompanied by fluorescence quenching due to the photoinduced electron transfer effect between upconversion materials and PFOS. Under optimized experimental conditions, the fluorescence quenching efficiency of the probe has good linearity against the concentrations of PFOS response divided into two segments within linear ranges of 0.001-0.1 nmol/L and 0.1-1 nmol/L, respectively, with low detection limit of 1 pmol/L. Selective experiment results indicate that the C-F chain length plays a dominant role in molecular recognition and high sensitively detection. The fabricated probe shows well detection performance in a wide pH range. Furthermore, real samples analyses indicate that such an efficient fluorescent probe has potentials in PFOS determination in surface water, human serum and egg extract sample analyses.

Exposure assessment of PFAS-contaminated sites using avian eggs as a biomonitoring tool: A frame of reference and a case study in the Po River valley (Northern Italy)

For many years, eggs of diverse bird species have been used as monitoring tools in studies investigating perfluoroalkyl substances (PFAS) contamination, especially in marine and remote areas. Avian eggs are a suitable monitoring matrix because they are relatively easy to collect and their yolks store diverse maternally transferred PFAS. Moreover, the concentrations of PFAS detected in the eggs are a good proxy for maternal exposure and allow the assessment of the potential risk for birds. These features support the use of avian eggs as a key monitoring tool in exposure assessment of PFAS-contaminated sites. We first review the recent application of avian eggs in PFAS monitoring in environmental risk assessment schemes, highlighting strengths and limitations and suggesting which criteria should be considered when selecting a proper study species and structuring the sampling and analytical protocol. Eventually, we report findings from a field study realized in 2020 near a perfluoropolymer factory site in the upper Po plain (Northern Italy), revealing an unprecedented contamination level of PFOA and C6O4 in three species of wild passerines. In future, long-term monitoring of PFAS contamination using avian eggs should be maintained, to provide crucial information on the temporal trend of fluorochemical production and waste disposal, while facilitating early identification of emerging PFAS as well as the quantification of their biomagnification across the trophic web. Integr Environ Assess Manag 2021;17:733-745. © 2021 SETAC.

Perfluoroalkyl acid (PFAA) profile and concentrations in two co-occurring tit species: distinct differences indicate non-generalizable results across passerines

Eggs of terrestrial bird species have often been used to biomonitor both legacy and emerging anthropogenic contaminants, such as perfluoroalkyl acids (PFAAs). However, few, if any, studies have examined whether results obtained in a given model species can be generalized across bird species. Therefore, we compared potential differences in egg PFAA profile and concentrations between two widely studied passerine species, great tit (Parus major) and blue tit (Cyanistes caeruleus), which are similar in many aspects of their ecology and life history. Whole clutches of both species were collected from the same breeding season and at the same place (Antwerp, Belgium), enabling us to study laying order effects. Additionally, we evaluated how egg PFAA concentrations for both species changed along a distance gradient from a PFAA point source. Although the sum PFAA concentrations did not significantly differ between great tits and blue tits, large differences in PFAA profile and laying order effects were observed. Great tits showed a more diverse PFAA detection profile, including perfluorooctane sulfonic acid (PFOS) and various long-chain perfluorocarboxylic acids (PFCAs) but no short-chain compounds. Contrarily, short-chain PFCAs (perfluorobutanoic acid (PFBA) and perfluorohexanoic acid (PFHxA)) were only detected in blue tit eggs. The variation of perfluorooctanoic acid (PFOA) concentrations within clutches was large in both species, although laying order effects on PFOA concentrations were only found in blue tits. Although egg PFOA concentrations of both species decreased similarly from the fluorochemical point source onwards, more variation in egg PFOA concentrations could be explained by distance from the fluorochemical plant in great tits (60%) than in blue tits (15%). Results showed that both species markedly differed in terms of egg PFAA profile and concentrations, most likely reflecting differences in diet, foraging habits and egg protein composition. Finally, biomonitoring results of PFAAs in eggs are likely not generalizable across bird species.

Evaluation of Residues in Hen Eggs After Exposure of Laying Hens to Water Containing Per- and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) have been used in aqueous film-forming foams used in firefighting, resulting in soil and groundwater contamination and leading to human exposure via animal products grown in contaminated areas. The present study reports the relationship between PFAS intake by hens and the PFAS concentrations in the edible parts of eggs. Laying hens were exposed via drinking water to different concentrations of 4 PFAS compounds (perfluorooctane sulfonate [PFOS], perfluorohexane sulfonate [PFHxS], perfluorooctanoic acid [PFOA], and perfluorohexanoic acid) over 61 d. Egg PFAS residues were assessed for a further 30 d after exposure ceased. The target concentrations of PFAS were 0, 0.3, 3, 30, and 300 µg/L for the treatment groups T1-T5, respectively; and PFAS residues were determined from the eggs collected every second day. There was a linear correlation between the PFAS concentrations in the drinking water of hens and those detected in the egg, which could be useful in estimating PFAS concentrations in the egg by measuring water concentrations. Exposure of hens to drinking water with PFAS concentrations below the Australian Government Department of Health limits (PFOS and PFHxS, 0.07 µg/L; PFOA, 0.56 µg/L), and with no other sources of PFAS exposure, is unlikely to result in egg PFAS concentrations that would exceed the 10% limit set by Food Standards Australia New Zealand for human consumption. Environ Toxicol Chem 2021;40:735-743. © 2020 SETAC.

Species- and Tissue-Specific Avian Chronic Toxicity Values for Perfluorooctane Sulfonate (PFOS) and a Binary Mixture of PFOS and Perfluorohexane Sulfonate

To further characterize avian toxicity to environmental levels of select per- and poly-fluoroalkyl substances (PFAS), we established species- and tissue-specific PFAS chronic toxicity values (CTVs) associated with a lowest-observable-adverse effect level (LOAEL) threshold previously established for northern bobwhite quail (Colinus virginianus) chronically orally exposed via drinking water to either perfluorooctane sulfonate (PFOS) or a simple PFAS mixture. Aided by advances in analytical techniques, the novel avian oral PFAS CTVs reported in the present study are lower than the previously reported toxicity reference values (TRVs) estimated for birds chronically exposed via feed. Thus, current avian PFOS TRVs may not be fully protective of wild avian populations at PFAS-impacted sites. Also, likely due to differences in bioavailability, bioaccessibility, and toxicokinetics among individual PFAS between oral exposure types, we found higher bioaccumulation factors in all assessed tissues from birds exposed via water versus feed. Thus, we propose that future characterization of chemical toxicity due to ingestion exposure initially include a full examination of all probable sources of oral exposure for the most accurate derivation of TRVs and a more complete picture of ecological risk. The avian PFAS LOAEL CTVs established in the present study can be modified with the use of uncertainty factors to derive site-specific avian TRVs for ecological risk assessment at PFAS-impacted sites. From differences observed in the behavior of PFOS when administered as either a single chemical or part of a binary mixture with perfluorohexane sulfonate (PFHxS), we verified that PFOS was absorbed and distributed differently when coadministered with PFHxS and that PFOS likely interacted with PFHxS differently among tissues, helping to explain the differences observed in avian toxicity between exposures. Environ Toxicol Chem 2021;40:899-909. © 2020 SETAC.

[Perfluoroalkyl and polyfluoroalkyl substances in eggs: analytical methods and their application as pollutant bioindicator]

Perfluoroalkyl and polyfluoroalkylated substances (PFASs) are environmentally persistent and biomagnified along food chains. They have been widely detected globally, even in the human body, and their potential toxicity has attracted great attention. Eggs are the origin of new life of ovipara and are rich in nutrients, thus they serve as one of the main protein sources for humans. Therefore, the level of pollutants in eggs can affect the reproduction of ovipara, and it is also related to human health by food intake. In recent years, poultry egg samples have been widely used in the assessment of biological and ecological pollution as a non-invasive biota matrix. At the same time, recent studies have used eggs to evaluate the developmental toxicity and associated health risks based on the pollutant levels in egg samples. In this study, the methods of sample pretreatment and instrumental detection of PFASs for egg samples are summarized. In addition, the application of eggs as a pollutants bioindicator of PFASs contamination has been discussed.

Transfer of Per- and Polyfluoroalkyl Substances (PFAS) from Feed into the Eggs of Laying Hens. Part 1: Analytical Results Including a Modified Total Oxidizable Precursor Assay

The group of per- and polyfluoroalkyl substances (PFAS) comprises thousands of chemicals, which are used in various industrial applications and consumer products. In this study, a feeding experiment with laying hens and feed grown on a contamination site was conducted, and PFAS were analyzed in the feed and eggs to assess the transfer of PFAS into eggs. A targeted analysis of perfluoroalkyl acids (PFAAs) and different sulfonamides was performed. Additionally, the total oxidizable precursor (TOP) assay was modified by fully oxidizing small amounts of the samples instead of oxidizing their extracts in order to overcome potential losses during extraction. Targeted analysis showed the presence of known PFAAs and four sulfonamides in the feed and egg yolk samples. In the plant-based feed, short-chain PFAAs, methyl and ethyl perfluorooctane sulfonamidoacetic acid (Me- and EtFOSAA), and perfluorooctane sulfonic acid (PFOS) were the most abundant PFAS. In the eggs, PFOS, FOSAA, and its alkylated homologues showed the highest concentrations. The TOP assay revealed the presence of substantial amounts of precursors with different chain lengths from C4 to C8. The highest relative increase of PFOA after oxidation was observed in egg yolk from the end of the exposure period (828%). The results of this study demonstrate the transfer of PFAAs and their precursors into hens' eggs and emphasize the contribution of (known and unidentified) precursors to the overall PFAS burden in edible products. The modified TOP assay approach was shown to be a powerful tool to better assess the total burden of samples with PFAS.

Distribution and effects of branched versus linear isomers of PFOA, PFOS, and PFHxS: A review of recent literature

Perfluorinated alkyl substances (PFAS) have come to attention recently due to their widespread presence in the environment, recalcitrance, and potential negative health associations. Because of the long-term production of PFAS using ECF, which created branched isomers as byproducts in addition to the intended linear product, branched isomers of PFAS account for a significant portion of PFAS load in the environment. The distribution of isomers is not consistent in the environment, however. Geographic location appears to be a major factor in determining the isomer makeup of PFAS in surface and groundwater as well as in humans and animals. This is largely to differences in production methods; a region that produced PFAS via ECF for many years would have a higher ratio of branched isomers than one that produces PFAS using telomerization. In addition, the different structures of branched PFAS isomers as compared to linear PFAS appear to affect transport in the environment. Research suggests that linear PFAS sorb preferentially to soil and sediments, whereas branched isomers are more likely to remain in water. The higher polarity of the branched structure explains this difference. Studies in humans and animals show that most animals preferentially accumulate the linear PFOS isomer, but humans appear to preferentially accumulate the branched isomers as they are often found in human serum at percentages higher than that of ECF product. In addition, some studies have indicated that linear and branched PFAS isomers have some unique negative health associations. Very few studies, however, account for linear and branched PFAS separately.

Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) Determination of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) in the Yolk of Poultry Eggs in Malaysia

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are widely used in products, and are known for their water and grease repellent properties. The persistence nature and potential toxicity of these substances have raised substantial concerns about health effects. Regarding humans, food consumption has reportedly been a significant source of exposure for both compounds. Hence, this study was performed to develop and validate an analytical method for PFOS and PFOA in egg yolks using liquid chromatographic tandem mass spectrometry (LC-MS/MS) followed by the determination of concentration of both compounds in the yolk of poultry eggs in Malaysia. A total of 47 poultry egg yolk samples were extracted by a simple protein precipitation technique using acetonitrile. The analytical method was developed using LC-MS/MS and validated based on the Food and Drug Administration (FDA)’s Bioanalytical Method Validation guidelines. The results revealed that PFOS was quantitatively detected in six samples, with the concentration range between 0.5 and 1.01 ng g⁻¹. Among these, five samples were from home-produced chicken eggs, and one sample was from a quail egg. The levels of PFOA in all samples were below the quantifiable limit (<0.1 ng g⁻¹). This indicated that the contamination of PFCs in poultry eggs were mostly attributed to the nature of free foraging animals, which had direct contact with the contaminants in soil and feed. In conclusion, a fast and robust analytical method for analyzing PFOS and PFOA in egg yolk samples using LC-MS/MS was successfully developed and validated. The presence of these emerging contaminants in this study signified widespread pollution in the environment.

Assessing exposure to legacy and emerging per- and polyfluoroalkyl substances via hair - The first nationwide survey in India

In recent years, environmental issues emerging from per- and polyfluoroalkyl substances (PFAS) have raised high concern worldwide. Levels of human exposure to PFAS remain unknown in India. Biomonitoring data obtained from hair analysis have been evidenced to provide insight into retrospective human exposure to PFAS. In this study, 25 PFAS, including perfluoroalkyl acids and their precursors, were measured in 39 human hair samples collected from 14 cities in India. The inuflence of gender on the PFAS levels was also examined. To our knowledge, this is the first attempt to provide preliminary indicative data (due to the limited sample size and variability in hair-length sampling) on the levels of PFAS in Indian hair. The concentrations of total PFAS in hair varied from below matrix-specific limit of quantification (<0.02 ng/g) to 3.78 ng/g. Among 9 PFAS quantified, perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), and perfluorooctanoic acid (PFOA) were the predominant compounds. Categorized into 4 regions, PFAS contamination exhibited certain regional difference where South India may show higher levels than the other regions. Highly significant positive correlation was observed between PFHxS and PFOS (p ≪ 0.001; r = 0.644), suggesting similar pathways of exposure to the two compounds. Higher PFAS occurrence was generally observed in the hair of females. Our results highlighted the urgent need to investigate the deposition mechanism of PFAS in hair.

Levels, spatial distribution and isomer profiles of perfluoroalkyl acids in soil, groundwater and tap water around a manufactory in China

In this study, 32 surface soil samples, 24 groundwater samples, and 6 tap water samples were collected around a perfluorosulfonates (PFSAs) manufactory in China to analyze the distributions of perfluoroalkyl acids (PFAAs) including linear and branched isomers. The total concentrations of PFAAs (∑PFAAs) ranged from 1.30 to 913 ng/g on a dry weight basis (dw), 31.4-15656 ng/L, and 11.8-59.7 ng/L in soil, groundwater and tap water samples respectively. Perfluorooctanesulfonate (PFOS) and perfluorobutanoic acid (PFBA) were the predominant PFAAs in the soil whereas PFBA was the predominant congener in groundwater. PFAA concentrations in the soil and groundwater decreased with increasing distance from the manufactory. Shorter-chain PFAAs showed higher proportions in groundwater than in soil samples and that shorter-chain PFAAs exhibited faster decreasing rates in soil samples, which may be due to the differences in the polarity and hydrophobicity of these molecules. For isomer profiles, n-PFHxS, n-PFOS, and n-PFOA were the main isomer in soil samples and groundwater samples. Direct exposure to PFOS and PFOA via the soil and tap water posed relatively low risk to the residents' health.