Analysis of emerging per- and polyfluoroalkyl substances: Progress and current issues

Rethinking alternatives to fluorinated pops in aqueous environment and corresponding destructive treatment strategies

Alternatives are being developed to replace fluorinated persistent organic pollutants (POPs) listed in the Stockholm Convention, bypass environmental regulations, and overcome environmental risks. However, the extensive usage of fluorinated POPs alternatives has revealed potential risks such as high exposure levels, long-range transport properties, and physiological toxicity. Therefore, it is imperative to rethink the alternatives and their treatment technologies. This review aims to consider the existing destructive technologies for completely eliminating fluorinated POPs alternatives from the earth based on the updated classification and risks overview. Herein, the types of common alternatives were renewed and categorized, and their risks to the environment and organisms were concluded. The efficiency, effectiveness, energy utilization, sustainability, and cost of various degradation technologies in the treatment of fluorinated POPs alternatives were reviewed and evaluated. Meanwhile, the reaction mechanisms of different fluorinated POPs alternatives are systematically generalized, and the correlation between the structure of alternatives and the degradation characteristics was discussed, providing mechanistic insights for their removal from the environment. Overall, the review supplies a theoretical foundation and reference for the control and treatment of fluorinated POPs alternatives pollution.

Non-targeted analysis of per- and polyfluorinated substances in consumer food packaging

This study sought to develop a non-targeted workflow using high-resolution mass spectrometry (HRMS) to investigate previously unknown PFAS in consumer food packaging samples. Samples composed of various materials for different food types were subjected to methanolic extraction, controlled migration with food simulants and total oxidizable precursor (TOP) assay. The developed HRMS workflow utilized many signatures unique to PFAS compounds: negative mass defect, diagnostic breakdown structures, as well as retention time prediction. Potential PFAS features were identified in all packaging studied, regardless of food and material types. Five tentatively identified compounds were confirmed with analytical standards: 6:2 fluorotelomer phosphate diester (6:2 diPAP) and one of its intermediate breakdown products 2H-perfluoro-2-octenoic acid (6:2 FTUCA), perfluoropentadecanoic acid (PFPeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA). Longer perfluorocarboxylic acids including C17 and C19 to C24 were also found present within a foil sample. Concentrations of 6:2 FTUCA ranged from 0.78 to 127 ng g-1 in methanolic extracts and up to 6 ng g-1 in food simulant after 240 h migration test. These results demonstrate the prevalence of both emerging and legacy PFAS in food packaging samples and highlight the usefulness of non-targeted tools to identify PFAS not included in targeted methods.

Environmental occurrence, bioaccumulation and human risks of emerging fluoroalkylether substances: Insight into security of alternatives

Per- and polyfluoroalkyl substances (PFASs) are widely used due to their unique structure and excellent performance, while also posing threats on ecosystem, especially long-chain perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). As the control of conventional PFASs, fluoroalkylether substances (ether-PFASs) as alternatives are constantly emerging. Subsequently, the three representative ether-PFASs, chlorinated polyfluoroalkyl ether sulfonic acid (F-53B), hexafluoropropylene oxide-dimer acid (HFPO-DA), and 4,8-Dioxa-3H-perfluorononanoicacid (ADONA) are discovered and have received more attention in the environment and ecosystem. But their security is now also being challenged. This review systematically assesses their security from six dimensions including environmental occurrence in water, soil and atmosphere, as well as bioaccumulation and risk in plants, animals and humans. High substitution level is observed for F-53B, whether in environment or living things. Like PFOS or even more extreme, F-53B exhibits high biomagnification ability, transmission efficiency from maternal to infant, and various biological toxicity effects. HFPO-DA still has a relatively low substitution level for PFOA, but its use has emerged in Europe. Although it is less detected in human bodies and has a higher metabolic rate than PFOA, the strong migration ability of HFPO-DA in plants may pose dietary safety concerns for humans. Research on ADONA is limited, and currently, it is detected in Germany frequently while remaining at trace levels globally. Evidently, F-53B has shown increasing risk both in occurrence and toxicity compared to PFOS, and HFPO-DA is relatively safe based on available data. There are still knowledge gaps on security of alternatives that need to be addressed.

Metal-Organic Framework-Based Composites for the Adsorption Removal of Per- and Polyfluoroalkyl Substances from Water

The increasing health risks posed by per- and polyfluoroalkyl substances (PFASs) in the environment highlight the importance of implementing effective removal techniques. Conventional wastewater treatment processes are inadequate for removing persistent organic pollutants. Recent studies have increasingly demonstrated that metal-organic frameworks (MOFs) are capable of removing PFASs from water through adsorption techniques. However, there is still constructive discussion on the potential of MOFs in adsorbing and removing PFASs for large-scale engineering applications. This review systematically investigates the use of MOFs as adsorbents for the removal of PFAS in water treatment. This primarily involved a comprehensive analysis of existing literature to understand the adsorption mechanisms of MOFs and to identify factors that enhance their efficiency in removing PFASs. We also explore the critical aspects of regeneration and stability of MOFs, assessing their reusability and long-term performance, which are essential for large-scale water treatment applications. Finally, our study highlights the challenges of removing PFASs using MOFs. Especially, the efficient removal of short-chain PFASs with hydrophilicity is a major challenge, while medium- to long-chain PFASs are frequently susceptible to being captured from water by MOFs through multiple synergistic effects. The ion-exchange force may be the key to solving this difficulty, but its susceptibility to ion interference in water needs to be addressed in practical applications. We hope that this review can provide valuable insights into the effective removal and adsorption mechanisms of PFASs as well as advance the sustainable utilization of MOFs in the field of water treatment, thereby presenting a novel perspective.

A targeted and non-targeted discovery screening approach for poly-and per-fluoroalkyl substances in model environmental biota samples

A comprehensive analytical approach for targeted and non-targeted discovery screening of per- and polyfluoroalkyl substances (PFAS) was developed and applied to model complex environmental biotic samples. Samples were extracted by formic acid-acetonitrile solution and cleaned up and fractionated by SPE (WAX). Target PFAS quantification was performed by ultra-high performance liquid chromatography interfaced with a triple quadrupole mass spectrometer (UPLC-QqQ-MS/MS). Non-targeted analysis (NTA) PFAS screening was performed with UPLC coupled with a quadrupole-Exactive orbitrap high resolution mass spectrometer (UPLC-Q-Exactive-HRMS). An iterative exclusion (IE) approach was applied to data acquisition for NTA suspect screening to increase the potential for unknown PFAS discovery with MS/MS. A complex workflow in Compound Discoverer was set up to automate data processing of the PFAS suspects search. New mass lists and MS/MS databases, which included a large number of PFAS, were set up and introduced into the search for high-throughput structure identification using HRMS techniques. The integrated targeted-NTA method successfully analyzed for legacy and alternative PFAS in model environmental biota samples, namely polar bear liver and bird egg samples. Targeted analysis provided unequivocal identification of well known/established PFAS (mainly perfluoroalkyl acids) with quantification at very low levels. The NTA suspect screening was able to determine a broader range of PFAS. The data analysis method offered high-confidence annotations for PFAS despite lacking available authentic standards. Overall, the analytical coverage of PFAS was greater and elucidated other PFAS present in these model apex predators.

Emerging and legacy perfluoroalkyl and polyfluoroalkyl substances (PFAS) in surface water around three international airports in China

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large category of crucial environmental contaminants of global concerns. There are limited data on PFAS in surface water around international airports in China. The present study investigated the concentrations, distributions, and sources of emerging and legacy PFAS in surface waters around Beijing Capital International Airport (BC), Shanghai Pudong International Airport (SP), and Guangzhou Baiyun International Airport (GB) in China. Twenty-seven target compounds were quantified. The Σ27PFAS concentrations ranged from 19.0 to 62.8 ng/L (mean 36.1 ng/L) in BC, 25.6-342 ng/L (mean 76.0 ng/L) in SP, 7.35-72.7 ng/L (mean 21.6 ng/L) in GB. The dominant compound was perfluorooctanoic acid (PFOA), which accounted for an average of 27% (5%-65%) of the Σ27PFAS concentrations. The alternatives with -C6F12- group had detection frequencies ranging from 72% to 100%. The partition coefficient results indicate that the longer chain PFAS (C > 8) tend to be more distributed in the particle phase. Fifty suspect and nontarget PFAS were identified. In GB, 44 PFAS were identified, more than SP of 39 and BC of 38. An ultra short-chain (C = 2) precursor, N-methylperfluoroethanesulfonamido acetic acid (MeFEtSAA), was identified and semi-quantified. Domestic wastewater discharges might be the main sources around BC, while industrial and aviation activities might be the main sources around SP and GB.

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.

Nontarget Analysis and Comprehensive Characterization of Iodinated Polyfluoroalkyl Acids in Wastewater and River Water by LC-HRMS with Cascade Precursor-Ion Exclusions and Algorithmic Approach

Poly- and perfluoroalkyl acids (PFAAs) are a large family of widespread contaminants of worldwide concern and well-known as "forever chemicals". Direct emission of PFAAs from the fluorochemical industry is a crucial source of PFAA pollutants in the environment. This study implemented nontarget analysis and comprehensive characterization for a category of new PFAA contaminants, i.e., iodinated PFAAs (IPFAAs), in fluorochemical industry wastewater and relevant contaminated river water by liquid chromatography-high-resolution mass spectrometry with a cascade precursor ion exclusion (PIE) strategy and in-house developed data extraction and processing algorithms. A total of 26 IPFAAs (including 2 isomers of an IPFAA) were found and identified with tentative molecular structures. Semiquantification of the IPFAAs was implemented, and the total concentrations of IPFAAs were 0.16-285.52 and 0.15-0.17 μg/L in wastewater and river water, respectively. The high concentrations in association with the predicted ecotoxicities and environmental behaviors demonstrate that these IPFAAs are worthy of more concern and further in-depth research. The cascade PIE strategy along with the data extraction and processing algorithms can be extended to nontarget analysis for other pollutants beyond IPFAAs. The nontarget identification and characterization outcomes provide new understanding on the environmental occurrence and pollution status of IPFAAs from a comprehensive perspective.

Analytical approaches for screening of per- and poly fluoroalkyl substances in food items: A review of recent advances and improvements

Per and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals characterized by their ubiquitous nature in all environmental compartments which makes them of increasing concern due to their persistence, bioaccumulation, and toxicity (PBT). Several instrumental methodologies and separation techniques have been identified in the literature for the detection and quantification of PFAS in environmental samples. In this review, we have identified and compared common separation techniques adopted for the extraction of PFAS in food items, and analytical methodologies for identification and quantification of PFAS in food items of plant and animal origin, highlighting recent advances in tandem techniques for the high selectivity and separation of PFAS related compounds as well as knowledge gaps and research needs on current analytical methodologies.

Discovery of 35 novel classes of per- and polyfluoroalkyl substances in representative commercial fluorinated products in China

Per- and polyfluoroalkyl substances (PFAS) have received increasing scientific and regulatory attention due to their global distribution and health hazards. However, little is known about the PFAS composition of fluorinated products commercially available in China. In this study, a sensitive and robust analytical method was proposed for the comprehensive characterization of PFAS in aqueous film-forming foam and fluorocarbon surfactants in the domestic market based on liquid chromatography-high resolution mass spectrometry in full scan acquisition mode followed by parallel reaction monitoring mode. Consequently, a total of 102 PFAS from 59 classes were elucidated, of which 35 classes are reported for the first time, including 27 classes of anionic, seven classes of zwitterionic, and one class of cationic PFAS. The anionic-type products are mainly C6 fluorotelomerization-based (FT-based) PFAS. Perfluorooctanoic acid and perfluorooctane sulfonate are negligible, while some known electrochemical fluorination-based long-chain precursors in zwitterionic products are worthy of concern because of their high abundance and potential degradation. New precursors detected in zwitterionic products are FT-based PFAS, for example, 6:2 FTSAPr-AHOE and 6:2 FTSAPr-diMeAmPrC. The structural elucidation of PFAS in commercial products facilitates a better assessment of human exposure and environmental release.

Multifunctionalized Covalent Organic Frameworks for Broad-Spectrum Extraction and Ultrasensitive Analysis of Per- and Polyfluoroalkyl Substances

The contamination of surface and ground water by per- and polyfluoroalkyl substances (PFASs) has become a growing concern, and the structural diversity of PFASs is the major challenge for their ubiquitous applications. Strategies for monitoring coexistent anionic, cationic, and zwitterionic PFASs even at trace levels in aquatic environments are urgently demanded for effective pollution control. Herein, novel amide group and perfluoroalkyl chain-functionalized covalent organic frameworks (COFs) named COF-NH-CO-F9 are successfully synthesized and used for highly efficient extraction of broad-spectrum PFASs, attributing to their unique structure and the multifunctional groups. Under the optimal conditions, a simple and high-sensitivity method is established to quantify 14 PFASs including anionic, cationic, and zwitterionic species by coupling solid-phase microextraction (SPME) with ultrahigh-performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS) for the first time. The established method displays high enrichment factors (EFs) of 66-160, ultrahigh sensitivity with low limits of detection (LODs) of 0.0035-0.18 ng L^-1, a wide linearity of 0.1-2000 ng L^-1 with correlation coefficient (R²) ≥0.9925, and satisfactory precision with relative standard deviations (RSDs) ≤11.2%. The excellent performance is validated in real water samples with recoveries of 77.1-108% and RSDs ≤11.4%. This work highlights the potential of rational design of COFs with the desired structure and functionality for the broad-spectrum enrichment and ultrasensitive determination of PFASs in real applications.

Quantification and characterization of PFASs in suspended particulate matter (SPM) of German rivers using EOF, dTOPA, (non-)target HRMS

In this study, we compare analytical methods for PFAS determination-target analysis, non-target screening (NTS), direct total oxidizable precursor assay (dTOPA) and extractable organically bound fluorine (EOF). Therefore, suspended particulate matter (SPM) samples from German rivers at different locations in time series from 2005 to 2020 were analyzed to investigate temporal and spatially resolved trends. In this study 3 PFAS mass balances approaches were utilized: (i) PFAA target vs. PFAS dTOPA, (ii) PFAS target vs. EOF and (iii) PFAS target vs. PFAS dTOPA vs. organofluorines NTS vs. EOF. Mass balance approach (i) revealed high proportions of precursor substances in SPM samples. For the time resolved analysis an increase from 94% (2005) to 97% in 2019 was observable. Also for the spatial resolved analysis precursor proportions were high with >84% at all sampling sites. Mass balance approach (ii) showed that the unidentified EOF (uEOF) fraction increased over time from 82% (2005) to 99% (2019). Furthermore, along the river courses the uEOF increased. In the combined mass balance approach (iii) using 4 different analytical approaches EOF fractions were further unraveled. The EOF pattern was fully explainable at the sampling sites at Saar and Elbe rivers. For the time resolved analysis, an increased proportion of the EOF was now explainable. However, still 27% of the EOF for the time resolved analysis and 25% of the EOF for the spatial resolved analysis remained unknown. Therefore, in a complementary approach, both the EOF and dTOPA reveal unknown gaps in the PFAS mass balance and are valuable contributions to PFAS risk assessment. Further research is needed to identify organofluorines summarized in the EOF parameter.

Determination of 21 per- and poly-fluoroalkyl substances in paper- and cardboard-based food contact materials by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry

In this work, a new analytical method was developed and validated for the determination of the total content of 21 per- and poly-fluoroalkyl substances (PFASs) in paper- and cardboard-based food contact materials (FCMs). This method is based on green ultrasound-assisted lixiviation followed by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). The method was validated in various paper- and cardboard-based FCMs, showing good linearity (R² ≥ 0.99), limits of quantification (1.7-10 μg kg^-1), accuracy (74-115%), and precision (RSD < 20%). The eco-friendly characteristics of the proposed analytical method were assessed according to the analytical eco-scale, demonstrating that it can be considered an excellent green analytical method (EcoScale score > 75). Finally, 16 field samples of paper- and cardboard-based FCMs, including pizza boxes, popcorn boxes, paper bags and cardboard boxes for potato fries, ice cream tubs, pastry trays, and cardboard-based packaging for cooked Spanish omelets, fresh grapes, frozen fish, and salads were analyzed, showing that they comply with the current European regulations regarding the studied PFASs. The developed method is currently accredited according to UNE-EN ISO/IEC 17025 by the Spanish National Accreditation Body (ENAC) to be implemented for official control analysis of FCMs in the Public Health Laboratory of Valencia, Generalitat Valenciana (Valencia, Spain).

Sources, occurrence and toxic effects of emerging per- and polyfluoroalkyl substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) cause potential threats to biota and are persistent and never-ending substances in the environment. Regulations and ban on legacy PFAS by various global organizations and national level regulatory agencies had shifted the fluorochemical production to emerging PFAS and fluorinated alternatives. Emerging PFAS are mobile and more persistent in aquatic systems, posing potential greater threats to human and environmental health. Emerging PFAS have been found in aquatic animals, rivers, food products, aqueous film-forming foams, sediments, and a variety of other ecological media. This review summarizes the physicochemical properties, sources, occurrence in biota and the environment, and toxicity of the emerging PFAS. Fluorinated and non-fluorinated alternatives for several industrial applications and consumer goods as the replacement of historical PFAS are also discussed in the review. Fluorochemical production plants and wastewater treatment plants are the main sources of emerging PFAS to various environmental matrices. Information and research are scarcely available on the sources, existence, transport, fate, and toxic effects of emerging PFAS to date.

Occurrence of perfluoroalkyl substances in the environment compartments near a mega fluorochemical industry: Implication of specific behaviors and emission estimation

With the stringent restrictions on long-chain per- and polyfluoroalkyl substances (PFASs), ether-PFASs are being widely used as alternatives. We estimated that the mega fluorochemical industrial park (FIP) in Shandong, China, had emitted a maximum of 5040 kg and 1026 kg of hexafluoropropylene oxides (HFPOs), and 7560 kg and 1890 kg of perfluorooctanoic acid (PFOA) to water and air during 2021. In the surface water, groundwater, outdoor dust, soil, tree leaf and bark collected in the vicinity of the FIP, PFOA was predominant, followed by HFPOs. The much higher percentage of HFPO dimer acid (HFPO-DA) in groundwater than in surface water verified that this compound was more mobile in porous media. The strong correlations between the main PFASs in outdoor dust and surface soil suggested that the soil PFASs were mainly derived from air deposition, particularly for HFPO trimer acid (HFPO-TA), which has a stronger binding affinity with particles than PFOA. High percentage of the hydroxylated product of 6:2 polyfluorinated ether sulfonic acid was observed in groundwater, implying reductive dechlorination might occur in groundwater. Strong correlations between PFASs in outdoor dust and those in tree leaf and bark magnified that tree could serve as a sampler to effectively monitor airborne PFASs. This study provides the first line of information about the discharge, transport, and fate of novel ether-PFASs in the multiple environmental media near a point source.

Sorptive removal of per- and polyfluoroalkyl substances from aqueous solution: Enhanced sorption, challenges and perspectives

Per- and polyfluoroalkyl substances (PFASs) have garnered attention globally given their ubiquitous occurrence, toxicity, bioaccumulative potential, and environmental persistence. Sorption is widely used to remove PFASs given its simplicity and cost-effectiveness. This article reviews recently fabricated sorbents, including carbon materials, minerals, polymers, and composite materials. The characteristics and interactions of the sorbents with PFASs are discussed to better understand sorptive processes. Various sorbents have exhibited high removal rates for legacy perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Novel polymers with special design better remove long- and short-chain PFASs than other sorbents. Although hydrophobic and electrostatic interactions mainly drive the sorption of anionic, cationic, and zwitterionic PFASs, enhancing PFAS sorption on designed sorbents has mainly depended on improving electrostatic interactions. Pearson correlation analysis showed that PFOS sorption capacity of sorbents is positively correlated with their specific surface area. Newly discovered pathways, including the air-water interfacial adsorption, F-F fluorophilic interactions, and (hemi) micelle formation, can enhance PFAS sorption to a certain extent. In addition to PFOA and PFOS, the sorption of emerging PFASs, including aqueous film-forming foam-relevant PFASs, constitutes a new research direction. The functionalization methods for enhancing PFAS sorption and challenges of PFAS sorption are also discussed to provide scope for future research. The discussions herein may contribute to developing efficient sorption technologies to remove PFASs.

Comprehensive profiles of per- and polyfluoroalkyl substances in Chinese and African municipal wastewater treatment plants: New implications for removal efficiency

Municipal wastewater treatment plants (WWTPs) can reflect the pollution status of per- and polyfluoroalkyl substances (PFASs) pollution. Here, matched influent, effluent, and sludge samples were collected from 58 municipal WWTPs in China, South Sudan, Tanzania, and Kenya. Target and suspect screening of PFASs was performed to explore their profiles in WWTPs and assess removal efficiency and environmental emissions. In total, 155 and 58 PFASs were identified in WWTPs in China and Africa, respectively; 146 and 126 PFASs were identified in wastewater and sludge, respectively. Novel compounds belonging to per- and polyfluoroalkyl ether carboxylic acids (PFECAs) and sulfonic acids (PFESAs), hydrogen-substituted polyfluorocarboxylic acids (H-PFCAs), and perfluoroalkyl sulfonamides (PFSMs) accounted for a considerable proportion of total PFASs (ΣPFASs) in Chinese WWTPs and were also widely detected in African samples. In China, estimated national emissions of ΣPFASs in WWTPs exceeded 16.8 t in 2015, with >60 % originating from emerging PFASs. Notably, current treatment processes are not effective at removing PFASs, with 35 of the 54 WWTPs showing emissions higher than mass loads. PFAS removal was also structure dependent. Based on machine learning models, we found that molecular descriptors (e.g., LogP and molecular weight) may affect adsorption behavior by increasing hydrophobicity, while other factors (e.g., polar surface area and molar refractivity) may play critical roles in PFAS removal and provide novel insights into PFAS pollution control. In conclusion, this study comprehensively screened PFASs in municipal WWTPs and determined the drivers affecting PFAS behavior in WWTPs based on machine learning models.

Selective cationic covalent organic framework for high throughput rapid extraction of novel polyfluoroalkyl substances

Novel per- and polyfluoroalkyl substances (PFASs) raise global concerns due to their toxic effects on environment and human health. However, researches on analytical methods of novel PFASs are lacking. Here, a kind of selective cationic covalent organic framework (iCOF) was designed and loaded on the surface of cotton as an adsorbent. Then, a simple solid-phase extraction (SPE) method based on the cotton@iCOF was developed for high throughput rapid extraction of six novel PFASs in water samples, coupled with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) determination. Several important SPE parameters, such as the amount of iCOF, sample pH, desorption conditions and salinity were systematically investigated. Under optimal conditions, the limits of detection and quantification of this SPE-UHPLC-MS/MS method were as low as 0.08-2.14 ng/L and 0.28-7.15 ng/L, respectively. The recoveries were 77.9-117.6 % for the tap water and surface water, and F-53 B in surface water were detected. Notably, this SPE process was rapid (1 h for 500 mL water sample) compared with commercial SPE (normal 2-3 h), owing to little resistance of cotton@iCOF and omission of nitrogen blowing process, and high throughput with 12 samples concurrently extracted. Additionally, various characterization means and density functional theory (DFT) calculations showed that ion-exchange effect, hydrophobic interaction, hydrogen bonding and ordered channel structure synergistically contributed to the PFASs adsorption on cotton@iCOF. The cotton@iCOF-based SPE method with simplicity, rapidity, selectivity and efficiency provided new research ideas for the analysis and control of ionic emerging pollutants in water.

The effects of perfluoroalkyl and polyfluoroalkyl substances on female fertility: A systematic review and meta-analysis

OBJECTIVE

The reproductive toxicity of perfluoroalkyl and polyfluoroalkyl substances (PFAS) has been verified in both animal and in vitro experiments, however, the association between PFAS and female fertility remains contradictory in population studies. Therefore, in this systematic review and meta-analysis, we evaluated the effects of PFAS on female fertility based on population evidence.

METHODS

Electronic searches of the Web of Science, PubMed, The Cochrane Library, and Embase databases were conducted (from inception to March 2022) to collect observational studies related to PFAS and female fertility. Two evaluators independently screened the literature, extracted information and evaluated the risk of bias for the included studies, meta-analysis was performed using R software.

RESULTS

A total of 5468 records were searched and 13 articles fully met the inclusion criteria. Meta-analysis showed that perfluorooctanoic acid (PFOA) exposure was negatively associated with the female fecundability odds ratio (FOR = 0.88, 95% confidence interval (Cl) [0.78; 0.98]) and positively associated with the odds ratio for infertility (OR = 1.33, 95%Cl [1.03; 1.73]). Perfluorooctane sulfonate (PFOS) exposure was negatively associated with the fecundability odds ratio (FOR = 0.94, 95% CI [0.90; 0.98]). Pooled effect values for perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluorohexane sulfonate (PFHxS) exposure did not find sufficient evidence for an association with female fertility.

CONCLUSION

Based on the evidence provided by the current study, increased levels of PFAS exposure are associated with reduced fertility in women, this was characterized by a reduction in fecundability odds ratio and an increase in odds ratio for infertility. This finding could partially explain the decline in female fertility and provide insight into risk assessment when manufacturing products containing PFAS.

Fluoro-cotton assisted non-targeted screening of organic fluorine compounds from rice (Oryza sativa L.) grown in perfluoroalkyl substance polluted soil

The toxicity and environmental persistence of perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) are of great concern for food intake in humans. However, PFASs conversion or conjugation to other substances in rice grown on PFASs polluted soil has not been explored clearly. These unknown transformed or conjugated products of PFOA and PFOS could be harmful to human health. The restriction factor in evaluating the possible transformation of PFOA and PFOS is mainly attributed to the lack of an efficient method for screening PFOA and PFOS and their related metabolites. To circumvent this challenge, we established a non-targeted screening method by combining a fluoro-cotton fiber-based solid phase extraction (FC-SPE) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) to monitor the formation of possible organic fluorine compounds from rice (Oryza sativa L.) grown on PFASs. We synthesized fluoro-cotton fibers to serve as the FC-SPE packing material and characterized by field-emission scanning electron-microscope, Fourier transform infrared, and X-ray photoelectron spectroscopy measurements. The optimal extraction conditions for the prepared FC-SPE were investigated. The performance of FC-SPE in LC-MS analysis was validated by linearity, precision, recovery, and matrix effect. Then the FC-SPE combined with LC-HRMS was used to specifically capture organic fluorine compounds from complex matrices via F-F interaction, including rice seedlings grown in PFOA and PFOS polluted soil and soil samples. By the established FC-SPE LC-HRMS method, in total 429 features were found as the possible organic fluorine compounds from rice seedlings grown in PFOA polluted soil among the 1781 features from the rice seedlings. Finally, we employed a¹³C metabolic tracing analysis of organic fluorine compounds in combination with the FC-SPE LC-HRMS method to further identify the features that detected from rice seedlings grown in PFOA polluted soil. The final result indicated that there were not any new organic fluorine metabolites screened out from rice grown in PFOA or PFOS polluted soil.

The effects of endocrine-disrupting chemicals on ovarian- and ovulation-related fertility outcomes

Exposure to endocrine-disrupting chemicals (EDCs) is unavoidable, which represents a public health concern given the ability of EDCs to target the ovary. However, there is a large gap in the knowledge about the impact of EDCs on ovarian function, including the process of ovulation. Defects in ovulation are the leading cause of infertility in women, and EDC exposures are contributing to the prevalence of infertility. Thus, investigating the effects of EDCs on the ovary and ovulation is an emerging area for research and is the focus of this review. The effects of EDCs on gametogenesis, uterine function, embryonic development, and other aspects of fertility are not addressed to focus on ovarian- and ovulation-related fertility issues. Herein, findings from epidemiological and basic science studies are summarized for several EDCs, including phthalates, bisphenols, per- and poly-fluoroalkyl substances, flame retardants, parabens, and triclosan. Epidemiological literature suggests that exposure is associated with impaired fecundity and in vitro fertilization outcomes (decreased egg yield, pregnancies, and births), while basic science literature reports altered ovarian follicle and corpora lutea numbers, altered hormone levels, and impaired ovulatory processes. Future directions include identification of the mechanisms by which EDCs disrupt ovulation leading to infertility, especially in women.

Investigation of the Interaction between Human Serum Albumin and Branched Short-Chain Perfluoroalkyl Compounds

The current trend dealing with the production of per- and polyfluoroalkyl substances (PFASs) involves the shifting toward branched short-chain fluorinated compounds known as new-generation PFASs. A key aspect to be clarified, to address the adverse health effects associated with the exposure to PFASs, is their binding mode to human serum albumin (hSA), the most abundant protein in plasma. In this study, we investigated the interaction between hSA and two representative branched short-chain PFASs, namely, HPFO-DA and C6O4. In-solution studies revealed that both compounds bind hSA with affinities and stoichiometries lower than that of the legacy long-chain perfluoroalkyl compound PFOA. Competition experiments using hSA-binding drugs with known site-selectivity revealed that both HPFO-DA and C6O4 bound to pockets located in subdomain IIIA. The crystal structure of hSA in complex with HPFO-DA unveiled the presence of two binding sites. The characterization and direct comparison of hSA interactions with new-generation PFASs may be key elements for the understanding of the toxicological impact of these compounds.

Epidemiology Evidence for Health Effects of 150 per- and Polyfluoroalkyl Substances: A Systematic Evidence Map

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise a large class of chemicals with widespread use and persistence in the environment and in humans; however, most of the epidemiology research has focused on a small subset.

OBJECTIVES

The aim of this systematic evidence map (SEM) is to summarize the epidemiology evidence on approximately 150 lesser studied PFAS prioritized by the EPA for tiered toxicity testing, facilitating interpretation of those results as well as identification of priorities for risk assessment and data gaps for future research.

METHODS

The Populations, Exposure, Comparators, and Outcomes (PECO) criteria were intentionally broad to identify studies of any health effects in humans with information on associations with exposure to the identified PFAS. Systematic review methods were used to search for literature that was screened using machine-learning software and manual review. Studies meeting the PECO criteria underwent quantitative data extraction and evaluation for risk of bias and sensitivity using the Integrated Risk Information System approach.

RESULTS

193 epidemiology studies were identified, which included information on 15 of the PFAS of interest. The most commonly studied health effect categories were metabolic (n=37), endocrine (n=30), cardiovascular (30), female reproductive (n=27), developmental (n=26), immune (n=22), nervous (n=21), male reproductive (n=14), cancer (n=12), and urinary (n=11) effects. In study evaluation, 120 (62%) studies were considered High/Medium confidence for at least one outcome.

DISCUSSION

Most of the PFAS in this SEM have little to no epidemiology data available to inform evaluation of potential health effects. Although exposure to the 15 PFAS that had data was fairly low in most studies, these less-studied PFAS may be used as replacements for "legacy" PFAS, leading to potentially greater exposure. It is impractical to generate epidemiology evidence to fill the existing gaps for all potentially relevant PFAS. This SEM highlights some of the important research gaps that currently exist. https://doi.org/10.1289/EHP11185.

Exploring the origin of efficient adsorption of poly- and perfluoroalkyl substances in household point-of-use water purifiers: Deep insights from a joint experimental and computational study

Poly- and perfluoroalkyl substances (PFAS) are harmful chemicals to humans and widely detected in water bodies including tap water. PFAS cannot be efficiently removed from water through conventional treatment processes used in full-scale drinking water treatment plants, posing a latent risk to human health via drinking tap water. Here in-field investigations show that the household point-of-use (POU) water purifiers constituted with coconut shell activated carbon can achieve 21%-99% removal for 14 legacy and emerging PFAS in tap water based on the ratio of influent and effluent. Extensive characterizations combine with chemical analyses demonstrate that physical adsorption based on Van der Waals force can remove 23 PFAS from tap water, wherein the hydrophobicity of PFAS is the crucial factor. Density functional theory calculations together with the quantitative structure-activity relationship model confirm that both topological structures as well as hydrophobicity of PFAS and electrostatic interactions between the strong electronegative F atoms and the adsorbent surface are the most critical factors controlling the PFAS adsorption to activated carbon. Overall, our results offer insights into the molecular mechanisms that enable the adsorption of PFAS in POU filters.

Determination of total reducible organofluorine in PFAS-impacted aqueous samples based on hydrated electron defluorination

Per- and polyfluoroalkyl substances (PFASs) is a large group of thousands of anthropogenic chemicals. Recently, measurement of total organic fluorine (TOF) to reflect the total PFASs has been recommended in limits and advisories. In this study, a total reducible organofluorine (TROF) assay is developed based on hydrated electron (e_aq^-) conversion of PFASs into inorganic fluorine combined with ion chromatograph, which is a common and widespread instrument. The e_aq^- is generated in UV/sulfite system with alkaline condition, and the concentration of TROF (C_{F_TROF}) is the difference of fluoride concentration before and after assay. Method validation uses perfluorooctanesulfonic acid, perfluorooctanoic acid and their main alternatives, and F^- recoveries are 76.6%-101%, except for perfluorobutanesulfonic acid (48.5%). Method application of TROF assay uses industrial surfactant products and fluorochemical industry-contaminated water, meanwhile, target PFAS analysis and total oxidizable precursors (TOP) assay are concurrently conducted. Concentrations of PFASs detected in target analysis and TOP assay were converted to fluorine equivalents concentrations (C_{F_Target} and C_{F_TOP}). ∑C_{F_Target} and ∑C_{F_TOP} account for 0.80%-36% of C_{F_TROF} in industrial samples, 0.12%-54% in environmental water and 9.7%-14% in wastewater. The TROF assay can be used to initially judge whether PFASs contamination occurred near a hotspot with known sources. The C_{F_TROF} could infer the extent of PFAS contamination in PFAS-impacted samples and estimate the fraction of uncharacterized PFAS.

Nontargeted Identification and Temporal Trends of Per- and Polyfluoroalkyl Substances in a Fluorochemical Industrial Zone and Adjacent Taihu Lake

Various per- and polyfluoroalkyl substances (PFASs) remain undiscovered and unexplored in the environment. The goals of this study were to discover new species of PFASs in effluent and surface waters from a fluorochemical industrial zone, and to assess their concentration, distribution, and temporal trends in the adjacent natural environment. In total, 83 emerging PFASs from 14 classes were identified, 22 of which were reported for the first time. Authentic standards were synthesized for 13 per- and polyfluoroalkyl ether carboxylic acids (PFECAs), thereby greatly expanding the scope of PFAS-targeted monitoring. The newly identified compounds accounted for 27%-95% of the total PFAS concentrations. Of note, a novel diether carboxylic acid, 2-[2-(trifluoromethoxy)hexafluoropropoxy]tetrafluoropropanoic acid (C7 HFPO-TA) was detected at an extremely high concentration in the fluorochemical zone effluent (447 000 ng/L) and at a median concentration in the fluorochemical zone surface water (670 ng/L), with detectable levels also found in the natural environment, that is, Wangyu River (23 ng/L) and Taihu Lake (5.6 ng/L). The distinct geographic distribution of C7 HFPO-TA suggests transport from the industrial point source to Taihu Lake via the Wangyu River. The concentration of C7 HFPO-TA in Taihu Lake, along with that of many other emerging PFASs, continued to grow in three sampling campaigns from 2016 to 2021. Considering the environmental persistence and toxicity of structurally similar PFECAs (e.g., HFPO-DA), studies on C7 HFPO-TA are urgently needed.

Degradation of OBS (Sodium p-Perfluorous Nonenoxybenzenesulfonate) as a Novel Per- and Polyfluoroalkyl Substance by UV/Persulfate and UV/Sulfite: Fluorinated Intermediates and Treatability in Fluoroprotein Foam

Sodium p-perfluorous nonenoxybenzenesulfonate (OBS) is a novel fluorosurfactant used as the alternative to perfluorooctanesulfonic acid (PFOS) in several applications such as fire-fighting foams and chemical enhanced oil recovery ("EOR") in China, with the annual production capacity of about 3,500 t. Here, for the first time, we investigated the degradability of OBS under the conditions of UV/persulfate (UV/PS) and UV/sulfite (UV/SF) as typical redox processes. A higher reaction rate (1.05 min^-1) and total organic carbon (TOC) reduction (46.9%) but a low defluorination rate (27.6%) along with the formation of a series of fluorinated intermediates were found in UV/PS, while a high defluorination rate (87.7%) was realized in UV/SF. In particular, a nontargeted workflow using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF-MS) was established to detect fluorinated intermediates. Combined with the theoretical calculation, the distinctive degradation pathways in both oxidation and reduction processes were proposed. The degradation mechanism of OBS in UV/SF was proposed to be H/F exchange and subsequent HF elimination. Furthermore, the diluted OBS-based fluoroprotein (FP) foam was used to investigate the degradation of OBS, which confirms the treatability using the redox approach. This work provides insights into the degradability of OBS, fluorinated intermediate search, and proper treatment of related contamination.

Occurrence and fate of poly- and perfluoroalkyl substances (PFAS) in urban waters of New Zealand

Information on the occurrence of PFAS in aquatic matrices of countries with no PFAS manufacturing, e.g., New Zealand, is limited. Also, the fingerprint of PFAS along an urban water cycle, following water path from wastewater treatment plant (WWTP) effluent to treated drinking water has not been widely assessed. Hence, 38 long-, short-, ultrashort-chain PFAS and fluorinated alternatives (including precursors) were monitored in this study by collecting composite samples from two urban WWTPs of New Zealand and grab samples from the water bodies receiving the WWTPs' effluents and a drinking water treatment plant, whose source water received the effluent of one of the studied WWTPs. ∑PFAS at concentrations 0.1 - 13 ng/L were detected in all wastewater samples, including influents and different treatment stages of the two WWTPs (WW1 and WW2). The fate of most PFAS was similar in the two WWTPs, despite large differences in WWTPs' PFAS loads in the influents, serving populations (1.6 vs 0.16 million), total capacities (300 vs 54 million liters per day), and designs (aerobic and anoxic secondary treatment vs aerobic only). The fate of PFAS in WWTPs appeared to be driven by a range of processes. For instance, a simultaneous increase (41.6%) in short-chain perfluorohexanoic acid (PFHxA) concentrations and decrease (49.7%) in precursor 6:2 fluorotelomer sulfonate (6:2 FTS) concentrations after secondary biological treatment suggested possible transformation of 6:2 FTS into PFHxA during the treatment. In contrast, the reason behind an average decrease of 35% in ultrashort-chain perfluoropropionic acid (PFPrA) concentrations after treatment was unclear, and further studies are recommended. The concentrations of a linear isomer of long-chain perfluorosulfonic acid (PFOS-L) decreased (48%) in the effluent, possibly due to its partitioning to sludge. Although the concentrations of PFAS in coastal waters suggested that the WW1 effluent is a potential source of PFAS, earlier dispersion model and no detection of PFAS in the receiving waters of WW2 implied that other sources, such as septic systems, peripheral industries, and the airport, could also be contributing to PFAS in coastal waters. The source of ultrashort-chain PFPrA (5.5 ng/L) detected in the treated drinking water produced from that river was unclear. The monitoring results confirm incomplete removal of PFAS in WWTPs, indicate a possible transformation of unknown precursors present in wastewater into short-chain perfluoroalkylcarboxylic acids (PFCAs) during biological treatment, and reveal a possible accumulation of perfluoroalkylsulfonic acids (PFSAs) in the sludge, overall suggesting the circulation of PFAS in urban water systems.

Per- and poly-fluoroalkyl substances (PFAS) and female reproductive outcomes: PFAS elimination, endocrine-mediated effects, and disease

Per- and poly-fluoroalkyl substances (PFAS) are widespread environmental contaminants frequently detected in drinking water supplies worldwide that have been linked to a variety of adverse reproductive health outcomes in women. Compared to men, reproductive health effects in women are generally understudied while global trends in female reproduction rates are declining. Many factors may contribute to the observed decline in female reproduction, one of which is environmental contaminant exposure. PFAS have been used in home, food storage, personal care and industrial products for decades. Despite the phase-out of some legacy PFAS due to their environmental persistence and adverse health effects, alternative, short-chain and legacy PFAS mixtures will continue to pollute water and air and adversely influence women's health. Studies have shown that both long- and short-chain PFAS disrupt normal reproductive function in women through altering hormone secretion, menstrual cyclicity, and fertility. Here, we summarize the role of a variety of PFAS and PFAS mixtures in female reproductive tract dysfunction and disease. Since these chemicals may affect reproductive tissues directly or indirectly through endocrine disruption, the role of PFAS in breast, thyroid, and hypothalamic-pituitary-gonadal axis function are also discussed as the interplay between these tissues may be critical in understanding the long-term reproductive health effects of PFAS in women. A major research gap is the need for mechanism of action data - the targets for PFAS in the female reproductive and endocrine systems are not evident, but the effects are many. Given the global decline in female fecundity and the ability of PFAS to negatively impact female reproductive health, further studies are needed to examine effects on endocrine target tissues involved in the onset of reproductive disorders of women.

Development and validation of an LC-MS/MS method for the quantitation of 30 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in human plasma, including HFPO-DA, DONA, and cC6O4

Per- and polyfluoroalkyl substances (PFASs) include persistent organic pollutants whose spread is still ubiquitous. Efforts to substitute substances of high concern with fluorinated alternatives, such as HFPO-DA (GenX), DONA (ADONA), and cC6O4, have been made. The aim of this work was to develop and validate an isotopic dilution liquid chromatography-tandem mass spectrometry (LC–MS/MS) method suitable to quantify 30 PFASs in human plasma. Analytes included legacy PFASs (PFOA, PFOS, and PFHxS), fluorinated alternatives (PFBA, PFBS, 6:2 FTSA, HFPO-DA, DONA, and cC6O4), and newly identified compounds (F-53B and PFECHS). The sample preparation was rapid and consisted of simple protein precipitation and centrifugation. Calibration standards and quality control solutions were prepared with a human pooled plasma containing relatively low background levels of the considered analytes. A complete validation was carried out: the lower limits of quantitation (LLOQs) ranged from 0.009 to 0.245 µg/L; suitable linearity (determination coefficients, R² 0.989–0.999), precision (2.0–19.5%, relative standard deviation), and accuracy (87.9–113.1% of theoretical) were obtained for considered concentration ranges. No significant variations of analyte responses were recorded under investigated storage conditions and during matrix effect tests. The external verification confirmed the accuracy of the method, although limited to 12 analytes. The method was also applied to 38 human plasma samples to confirm its applicability. The developed assay is suitable for large-scale analyses of a wide range of legacy and emerging PFASs in human plasma. To our knowledge, this is the first published method including cC6O4 for human biomonitoring.

Screening and Discrimination of Perfluoroalkyl Substances in Aqueous Solution Using a Luminescent Metal-Organic Framework Sensor Array

The extensive production and large-scale use of perfluoroalkyl substances (PFASs) have raised their presence in aquatic environments worldwide. Thus, the facile and reliable screening of PFASs in aqueous systems is of great significance. Herein, we designed a novel fluorescent sensor array for the rapid screening and discrimination of multiple PFASs in water. The sensor array comprised three highly stable zirconium porphyrinic luminescent metal-organic frameworks (i.e., PCNs) with different topological structures. The sensing mechanism was based on the static fluorescence quenching of PCNs by PFASs upon their adsorptive interactions. The fluorescence response patterns were characteristic for each PFAS because of their different adsorption affinities toward different PCNs. Through the interpretation of response patterns by statistical methods, the proposed PCN array successfully discriminated six different kinds of PFASs, each PFAS at different concentrations and PFAS mixtures at different molar ratios. The practicability of this array was further verified by effectively discriminating PFASs in two real water samples. Remarkably, the PCN sensors exhibited a very short response time toward PFASs (within 10 s) due to the ordered pore structure allowing fast PFAS diffusion. This study not only provides a facile method for rapid PFAS screening in waters but also broadens the application of luminescent metal-organic frameworks and array techniques in sensing fields.

Sensors for detecting per- and polyfluoroalkyl substances (PFAS): A critical review of development challenges, current sensors, and commercialization obstacles

Per- and polyfluoroalkyl substances (PFAS) are a class of compounds that have become environmental contaminants of emerging concern. They are highly persistent, toxic, bioaccumulative, and ubiquitous which makes them important to detect to ensure environmental and human health. Multiple instrument-based methods exist for sensitive and selective detection of PFAS in a variety of matrices, but these methods suffer from expensive costs and the need for a laboratory and highly trained personnel. There is a big need for fast, inexpensive, robust, and portable methods to detect PFAS in the field. This would allow environmental laboratories and other agencies to perform more frequent testing to comply with regulations. In addition, the general public would benefit from a fast method to evaluate the drinking water in their homes for PFAS contamination. A PFAS sensor would provide almost real-time data on PFAS concentrations that can also provide actionable information for water quality managers and consumers around the planet. In this review, we discuss the sensors that have been developed up to this point for PFAS detection by their molecular detection mechanism as well as the goals that should be considered during sensor development. Future research needs and commercialization challenges are also highlighted.

Utilization of a NIST SRM: a case study for per- and polyfluoroalkyl substances in NIST SRM 1957 organic contaminants in non-fortified human serum

The National Institute of Standards and Technology (NIST) generates and maintains thousands of Standard Reference Materials (SRMs) to serve commerce worldwide. Many SRMs contain metrologically traceable mass fractions of known organic chemicals and are commercially available to aid the analytical chemistry community. One such material, NIST SRM 1957 Organic Contaminants in Non-Fortified Human Serum, was one of the first materials issued by NIST with measurements for per- and polyfluoroalkyl substances (PFAS) listed on the Certificate of Analysis and was commercially available in 2009. Since the release of SRM 1957, nearly 400 units have been sold to date, and over 50 publications related to PFAS measurements have included this material for multiple analytical purposes, such as a quality control material, for interlaboratory comparison, as an in-house comparison tool, for inter- and intra-day measurement accuracy, as an indicator of isomeric patterns of PFAS, and for other uses. This perspective details the ways SRM 1957 is utilized by the analytical community and how data have been reported in the literature. A discussion on accurately comparing SRM data to generated data is included. Furthermore, we conducted an in-depth investigation around additional applications for NIST SRMs, such as a matrix-matched reference material, and for the identification of targeted compounds during high-resolution mass spectrometry data collection. Ultimately, this manuscript illustratively describes the ways to utilize a NIST SRMs for chemicals of emerging concern.

A Critical Review of a Recommended Analytical and Classification Approach for Organic Fluorinated Compounds with an Emphasis on Per- and Polyfluoroalkyl Substances

Organic fluorinated compounds have been detected in various environmental media and biota. Some of these compounds are regulated locally (e.g., perfluorononanoic acid maximum contaminant level in drinking water by the New Jersey Dept. of Environmental Protection), nationally (e.g., perfluorooctanoic acid maximum acceptable concentration in drinking water by Health Canada), or internationally (e.g., Stockholm Convention on Persistent Organic Pollutants). Globally, regulators and researchers seek to identify the organic fluorinated compounds associated with potential adverse effects, bioaccumulation, mobility, and persistence to manage their risks, and, to understand the beneficial attributes they bring to products such as first responder gear, etc. Clarity is needed to determine the best analytical method for the goal of the analyses (e.g., pure research or analysis to determine the extent of an accidental release, monitoring groundwater for specific compounds to determine regulatory compliance, and establish baseline levels in a river of organic fluorinated substances associated with human health risk prior to a clean-up effort). Analytical techniques that identify organic fluorine coupled together with targeted chemical analysis will yield information sufficient to identify public health or environmental hazards. Integr Environ Assess Manag 2021;17:331-351. © 2020. W.L. Gore & Associates Inc. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Per- and polyfluoroalkyl substances in soil and sediments: Occurrence, fate, remediation and future outlook

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are contaminants of great concern due to their wide-spread occurrence and persistence in the environments (i.e., in water, soil and sediment) and potential toxicology even at very low concentration. The main focus of this review is on the PFASs in soil and sediments. More specifically, this review systematically examines the occurrence and toxicological effects with associated risks, fate (i.e., PFASs adsorption by soil and sediment, transportation and transformation, and bioaccumulation), and remediation practices of PFASs in soil and sediment. Various models and equations such as fugacity-based multimedia fate and hydrodynamic models are used to study the fate, transport, and transformation of PFASs. Among different remediation practices, sorption is the dominant process for the removal of PFASs from soil and sediments. Results also indicate that PFASs adsorption onto activated carbon decrease with the increase of carbon chain length in the PFASs. The longer-chain PFASs have larger partition coefficient values than shorter-chained PFASs. Sorption of PFASs to soil and sediments are mainly governed by different electrostatic interactions, hydrogen bonds formation, hydrophobic interactions, organic content in soil and sediments, and ligand exchange. Other technology such as thermal treatment might be potential in the removal of PAFSs, but need further study to elucidate a conclusion. Finally, the associated challenges and future outlook have been included.

Rapid Characterization of Emerging Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foams Using Ion Mobility Spectrometry-Mass Spectrometry

Aqueous film-forming foams (AFFF) are mixtures formulated with numerous hydrocarbon- and fluoro-containing surfactants. AFFF use leads to environmental releases of unknown per- and polyfluoroalkyl substances (PFAS). AFFF composition is seldom disclosed, and their use elicits concerns from both regulatory agencies and the public because PFAS are persistent in the environment and potentially associated with adverse health effects. In this study, we demonstrate the use of coupled liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) to rapidly characterize both known and unknown PFAS in AFFF. Ten AFFF formulations from seven brands were analyzed using LC-IMS-MS in both negative and positive ion modes. Untargeted analysis of the formulations was followed by feature identification of PFAS-like features utilizing database matching, mass defect and homologous series evaluation, and MS/MS fragmentation experiments. Across the tested AFFF formulations, we identified 33 homologous series; only ten of these homologous series have been previously reported. Among tested AFFF, the FireStopper (n = 85) contained the greatest number of PFAS-like features and Phos-Check contained zero. This work demonstrates that LC-IMS-MS-enabled untargeted analysis of complex formulations, followed by feature identification using data-processing algorithms, can be used for rapid exposure characterization of known and putative PFAS during fire suppression-related contamination events.

Temporal Trends in Prenatal Exposure (1998-2018) to Emerging and Legacy Per- and Polyfluoroalkyl Substances (PFASs) in Cord Plasma from the Beijing Cord Blood Bank, China

Due to developmental toxicity, prenatal exposure to per- and polyfluoroalkyl substances (PFASs) in animals may result in adverse effects on the fetus. However, little information is available on PFASs presence in the human cord plasma. Here, we measured the levels of 37 emerging and legacy PFASs in 650 cord plasma samples collected every 5 years spanning 1998 to 2018 by the Beijing Cord Blood Bank and evaluated changes in PFASs concentrations using generalized additive models. We observed an increase in the concentrations of 24 PFASs (Σ₂₄PFASs) from 1998 to 2003 followed by a decrease every 5 years from 2003 to 2018. For legacy PFASs, similar trends were observed for PFOS, whereas PFOA levels did not decline until 2013. For emerging chemicals, 6:2 Cl-PFESA showed a similar trend as PFOS, and prenatal exposure to 6:2 Cl-PFESA could be traced back to 1998, with a median concentration of 0.411 ng/mL in plasma. Our data showed that prenatal exposure to legacy PFASs has gradually decreased in cord plasma from the Beijing Cord Blood Bank in recent years, and the discovery of the presence of emerging chemicals in 1998 suggested that further evaluation is needed to assess possible health risks to pregnant women and fetuses.

Robust Matrix Effect-Free Method for Simultaneous Determination of Legacy and Emerging Per- and Polyfluoroalkyl Substances in Crop and Soil Matrices

Increasing use of emerging per- and polyfluoroalkyl substances (PFASs) has caused extensive concerns around the world. Effective detection methods to trace their pollution characteristics and environmental behaviors in complex soil-crop systems are urgently needed. In this study, a reliable and matrix effect (ME)-free method was developed for simultaneous determination of 14 legacy and emerging PFASs, including perfluorooctanoic acid, perfluorooctane sulfonate, 6 hydrogenous PFASs, 3 chlorinated PFASs, and 3 hexafluoropropylene oxide homologues, in 6 crop (the edible parts) and 5 soil matrices using ultrasonic extraction combined with solid-phase extraction and ultraperformance liquid chromatography-mass spectrometry (MS)/MS. The varieties of extractants and cleanup cartridges, the dosage of ammonia hydroxide, and the ME were studied to obtain an optimal pretreatment procedure. The developed method had high sensitivity and accuracy with satisfactory method detection limits (2.40-83.03 pg/g dry weight) and recoveries (72-117%) of all target analytes in matrices at five concentrations, that is, 0.1, 1, 10, 100, and 1000 ng/g. In addition, the ME of this method (0.82-1.15) was negligible for all PFASs, even considering 11 different matrices. The successful application of the ME-free method to simultaneously determine the legacy and emerging PFASs in crop and soil samples has demonstrated its excellent practicability for monitoring emerging PFASs in soil-crop systems.

Legacy and alternative per- and polyfluoroalkyl substances in the U.S. general population: Paired serum-urine data from the 2013-2014 National Health and Nutrition Examination Survey

Concerns are heightened from detecting environmentally persistent man-made per- and polyfluoroalkyl substances (PFAS) in drinking water systems around the world. Many PFAS, including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), remain in the human body for years. Since 1999-2000, assessment of exposure to PFOS, PFOA, and other select PFAS in the U.S. general population has relied on measuring PFAS serum concentrations in participants of the National Health and Nutrition Examination Survey (NHANES). Manufacturers have replaced select chemistries ("legacy" PFAS) with PFAS with shorter biological half-lives (e.g., GenX, perfluorobutanoate [PFBA]) which may efficiently eliminate in urine. However, knowledge regarding exposure to these compounds is limited. We analyzed 2682 urine samples for 17 legacy and alternative PFAS in 2013-2014 NHANES participants ≥6 years of age. Concentrations of some of these PFAS, measured previously in paired serum samples from the same NHANES participants, suggested universal exposure to PFOS and PFOA, and infrequent or no exposure to two short-chain PFAS, perfluorobutane sulfonate and perfluoroheptanoate. Yet, in urine, PFAS were seldom detected; the frequency of not having detectable concentrations of any of the 17 PFAS was 67.5%. Only two were detected in >1.5% of the population: PFBA (13.3%) and perfluorohexanoate (PFHxA, 22.6%); the 90th percentile urine concentrations were 0.1 μg/L (PFBA), and 0.3 μg/L (PFHxA). These results suggest that exposures to short-chain PFAS are infrequent or at levels below those that would result in detectable concentrations in urine. As such, these findings do not support biomonitoring of short-chain PFAS or fluorinated alternatives in the general population using urine, and highlight the importance of selecting the adequate biomonitoring matrix.