Occurrence,Spatial Distribution,Sources and Risk Assessment of Per-and Polyfluoroalkyl Substances in Surface Sediments of the Yellow River Delta Wetland

Per-and polyfluoroalkyl substances(PFASs)are emerging persistent organic pollutants(POPs).In this study,47 surface sediment samples were collected from the Yellow River Delta wetland(YRDW)to investigate the occurrence,spatial distribution,potential sources,and ecological risks of PFASs.Twenty-three out of 26 targeted PFASs were detected in surface sediment samples from the YRDW,with totalΣ23PFASs concentrations ranging from 0.23 to 16.30 ng g^(-1) dw and a median value of 2.27 ng g^(-1) dw.Perfluorooctanoic acid(PFOA),perfluorobutanoic acid(PFBA)and perfluorooctanesulfonic acid(PFOS)were the main contaminants.The detection frequency and concentration of perfluoroalkyl carboxylic acids(PFCAs)were higher than those of perfluoroal-kanesulfonic acids(PFSAs),while those of long-chain PFASs were higher than those of short-chain PFASs.The emerging PFASs substitutes were dominated by 6:2 chlorinated polyfluoroalkyl ether sulfonic acid(6:2 Cl-PFESA).The distribution of PFASs is significantly influenced by the total organic carbon content in the sediments.The concentration of PFASs seems to be related to human activities,with high concentration levels of PFASs near locations such as beaches and villages.By using a positive matrix factorization model,the potential sources of PFASs in the region were identified as metal plating mist inhibitor and fluoropolymer manufacturing sources,metal plating industry and firefighting foam and textile treatment sources,and food packaging material sources.The risk assessment indicated that PFASs in YRDW sediments do not pose a significant ecological risk to benthic organisms in the region overall,but PFOA and PFOS exert a low to moderate risk at individual stations.

Distribution of per-and polyfluoroalkyl substances in blood,serum,and urine of patients with liver cancer and associations with liver function biomarkers

Studies have shown that per-and polyfluoroalkyl substances(PFASs)may be hepatotoxic in animals or humans.However,data on clinical epidemiology are very limited.In this study,21PFASs were determined in patients with liver diseases,with the highest median concentrations detected in the serum sample(26.7 ng/mL),followed by blood(10.7 ng/mL)and urine(5.02 ng/mL).Higher total PFAS concentrations were found in hepatocellular carcinoma(HCC)patients compared to non-HCC patients,with significant discrepancies in serum and blood samples.Besides,significant correlations were also found among PFAS concentrations and age,gender,body mass index(BMI),and liver function biomarkers levels.For example,PFAS concentrations are significantly higher in males than in females;Several serum PFASs concentrations increase with age and BMI,while the serum perfluorohexane sulfonic acid(PFHxS)concentrations are negatively correlated with age.In addition,multiple regression models adjusted for age,gender and BMI found that increased serum perfluorobutane sulfonic acid(PFBS),perfluoroheptane sulfonic acid(PFHpS)and perfluorohexylphosphonic acid(PFHxPA)conentrations are correlated with elevated alkaline phosphatase(ALP),aspartate aminotransferase(AST),and alpha-fetoprotein(AFP)(p<0.05).Our results provide epidemiological support for the future study on the potential clinical hepatotoxicity of PFAS.

Emergency of per-and polyfluoroalkyl substances in drinking water:Status,regulation,and mitigation strategies in developing countries

The detection of per-and polyfluoroalkyl substances(PFAS)in water presents a significant challenge for developing countries,requiring urgent attention.This review focuses on understanding the emergence of PFAS in drinking water,health concerns,and removal strategies for PFAS in water systems in developing countries.This review indicates the need for more studies to be conducted in many developing nations due to limited information on the environmental status and fate of PFAS.The health consequences of PFAS in water are enormous and cannot be overemphasized.Efforts are ongoing to legislate a national standard for PFAS in drinking water.Currently,there are few known mitigation efforts from African countries,in contrast to several developing nations in Asia.Therefore,there is an urgent need to develop economically viable techniques that could be integrated into largescale operations to remove PFAS from water systems in the region.However,despite the success achieved with removing long-chain PFAS from water,more studies are required on strategies for eliminating short-chain moieties in water.

Gestational PFAS exposure and newborn size:The modifying effect of cord blood fatty acids

Per-and polyfluoroalkyl substances(PFASs)can disrupt lipid metabolism,and changes in cord blood fatty acid composition have been observed in small newborns.Emerging evidence suggests that exposure to PFASs during pregnancy is linked to decreased newborn size,although the evidence is not consistent.The modifying effect of fatty acids on the associations of gestational PFAS exposure with newborn size is still unknown.Here we show that the nutritional status of the fetus,as indicated by the level of fatty acids in the cord blood,mitigates the adverse effects of gestational PFAS exposure on the size of the newborn.Our study confirms the adverse developmental effects of PFASs and identifies emerging short-chain PFASs as the primary drivers of reduced newborn size,despite their lower exposure burden compared to legacy PFASs.Additionally,we find the protective role of cord blood fatty acids,suggesting potential strategies for mitigating the detrimental effects of emerging environmental exposures on human health.Our findings provide new evidence of the potential toxicity of emerging PFASs and call for further toxicity evaluations of these pollutants for regulatory purposes.Future studies should consider the complex interaction between exposure and nutrition within the human body,particularly during the first thousand days of life,to promote lifelong health.

Interaction and combined toxicity of microplastics and per-and polyfluoroalkyl substances in aquatic environment

Microplastics(MPs)are recognized as vectors for the transport of organic contaminants in aquatic environments in addition to their own adverse effects on aquatic organisms.Per-and polyfluoroalkyl substances(PFASs)are widely present in aquatic environments due to their widespread applications,and thus coexist with MPs.Therefore,we focus on the interaction of MPs and PFASs and related combined toxicity in aquatic environments in this work The adsorption of PFASs on MPs is critically reviewed,and new mechanisms such as halogen bonding,π-πinteraction,cation-πinteractions,and micelle formation are proposed.Moreover,the effect of MPs on the transport and transformation of PFASs in aquatic environments is discussed.Based on four typical aquatic organisms(shellfish,Daphnia,algae,and fish),the toxicity of MPs and/or PFASs at the organismal or molecular levels is also evaluated and summarized.Finally,challenges and research perspectives are proposed,and the roles of the shapes and aging process of MPs on PFAS biogeochemical processes and toxicity,especially on PFAS substitutes,are recommended for further investigation.This review provides a better understanding of the interactions and toxic effects of coexisting MPs and PFASs in aquatic environments.

The occurrence of per-and polyfluoroalkyl substances(PFASs) in fluoropolymer raw materials and products made in China

Perfluorooctanoic acid(PFOA), its salts, and related compounds were listed as new persistent organic pollutants by the Stockholm Convention in 2019.In this study, the occurrence of residues of PFOA and other per-and polyfluoroalkyl substances(PFASs) in raw materials and fluoropolymer products from the Chinese fluoropolymer industries are reported for the first time.The PFOA concentrations in raw materials and fluoropolymer products were in the range of 6.7 to 1.1 × 10^(6) ng/g, and <MDL(method detection limit) to 5.3 × 10^(3) ng/g,respectively.Generally, the levels of PFOA in raw materials were higher than in products,implying that PFOA in the emulsion/dispersion resin could be partly removed during the polymerization or post-processing steps.By tracking a company’s polytetrafluoroethylene(PTFE) production line, it was found that over a 5 year period, the residual levels of PFOA in emulsion samples declined from 1.1 × 10^(6) to 28.4 ng/g, indicating that the contamination of PFOA in fluoropolymer products from production source gradually decreased after its use had been discontinued.High concentrations of HFPO-TrA(2.7 × 10^(5) to 8.2 × 10^(5) ng/g) were detected in some emulsion samples indicating this alternative has been widely applied in fluoropolymer manufacturing in China.

Temporal trends of per-and polyfluoroalkyl substances(PFAS)in the influent of two of the largest wastewater treatment plants in Australia

Per-and polyfluoroalkyl substances(PFAS)are found ubiquitously in wastewater treatment plants(WWTPs)due to their multiple sources in industry and consumer products.In Australia,limited spatial data are available on PFAS levels inWWTPs influent,while no temporal data have been reported.The aim of this study was to investigate the occurrence and temporal trend of PFAS in the influent of two large WWTPs in Australia(WWTP A and B)over a four-year period.Daily influent samples were collected over one week at different seasons from 2014 to 2017.Eleven perfluoroalkyl acids(PFAA)(i.e.seven perfluoroalkyl carboxylic acids(PFCAs)and four perfluoroalkyl sulfonic acids(PFSA))were detected with mean S11PFAA concentrations of 57±3.3e94±17 ng/L at WWTP A,and 31±6.1e142±73 ng/L at WWTP B.The highest mean concentrations were observed for perfluorohexanoate(PFHxA)(20±2 ng/L)in WWTP A,and perfluorooctane sulfonate(PFOS)(17±13 ng/L)in WWTP B.The precursor 6:2 fluorotelomer sulfonate was detected over five sampling periods from Aug 2016 to Oct 2017,with mean concentrations of 37±18e138±51 ng/L for WWTP A and 8.8±4.5e29±5.1 ng/L for WWTP B.Higher concentration of 6:2 FTS(1.8e11 folds)than those of PFOA and PFOS in WWTP A indicate a likely substitution of C8 PFAA by fluorotelomer-based PFAS in this catchment.Temporal trends(annual and seasonal)in per-capita mass load were observed for some PFAA,increasing for PFPeA,PFHxA,PFHpA,PFNA,and PFHxS,while decreasing for PFBS and PFOS in either WWTPs.Notably,elevated levels of PFOS in October 2017 were observed at both WWTPs with the highest per capita mass load of up to 67 mg/day/inhabitant.For some PFAS release trends,longer sampling periods would be required to achieve acceptable statistical power.

Diffusive gradients in thin films(DGT) probe for effectively sampling of per-and polyfluoroalkyl substances in waters and sediments

The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its effectiveness has been questioned because of the small effective sampling area(3.1 cm^(2)). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area(27 cm^(2)) and as a result lower method quantification limits(0.15 –0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher(by > 10 factors) sampling rate(100 m L/day) compared to the standard DGT(piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling(500m L). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.

Association between serum levels of TSH and free T4 and per- and polyfluoroalkyl compounds concentrations in pregnant women

Many per-and polyfluoralkyl substances(PFASs)may disrupt maternal thyroid hormone homeostasis in pregnancy.Concerns should be raised regarding the PFASs exposure in pregnant women because thyroid hormones are involved in the early development of the fetus.In this study,we measured the concentrations of 13 PFASs,including five novel shortchain PFASs,in serum from 123 pregnant women in Beijing,China.Linear regression models were used to investigate the association between thyroid-stimulating hormone(TSH)or free thyroxine(FT4)levels and PFASs concentrations under consideration of the impacts of pregnancy-induced physiological factors.We found that perfluorobutanoic acid(PFBA)(β=0.189,95%CI=-0.039,0.417,p=0.10)and perfluorodecanoic acid(PFDA)(β=-0.554,95%CI=-1.16,0.049,p=0.071)were suggestive of significant association with TSH in thyroid peroxidase antibody(TPOAb)negative women.No association was observed between all PFASs and FT4 levels after controlling for these confounding factors,such as BMI,gestational weight gain and maternal age.These findings suggest that it should pay more attention to the association between thyroid hormone levels and short-chain PFASs concentrations.Future studies could consider a greater sample and the inclusion of other clinical indicators of thyroid function,such as free T3 and total T3.

Influence of microplastics on the photodegradation of perfluorooctane sulfonamide (FOSA)

PFAS(per-and polyfluoroalkyl substances)are omnipresent in the environment and their transportation and transformation have attracted increased attention.Microplastics are another potential risk substances that can serve as a carrier for ubiquitous pollutants,thus affecting the presence of PFAS in the environment.In this study,the adsorption of perfluorooctane sulfonamide(FOSA)and perfluorooctanoic acid(PFOA)on four microplastics(PE,PVC,PS,and PTFE)and their effect on the photodegradation of FOSA were studied.The adsorption capacity of FOSA by PS was the highest,in similar,PS displayed the highest adsorption capacity in the presence of PFOA.Different effects of pH and salinity on the adsorption of FOSA and PFOA were observed among different microplastics indicating inconsistent interaction mechanisms.Furthermore,FOSA could be photodegraded,with PFOA as the main product,while the presence of microplastics had a negligible effect on the degradation of this contaminant.The results indicated that microplastics could act as PFAS concentrators.Moreover,their photochemical inertiasmake the pollutants enriched onmicroplastics more resistant to degradation.

PFAS in PMs might be the escalating hazard to the lung health

Atmospheric particulate matter(PM)is a dominant source of air pollution,in particular,molecules less than 2.5μm in diameter,endangering human health.An estimated 2.1 million deaths from exposure to PM2.5 and 700,000 cases of respiratory disease caused by atmospheric pollution were reported on an annual basis.The main components of PM2.5 include heavy metal elements,water-soluble ions,carbon aerosols,ozone,and organic compounds.Per-and polyfluoroalkyl substances(PFASs)are a large group of representative pollutants among the organic compounds absorbed in PM2.5.PFASs are widely used in industrial production and hardly degraded in the environment,resulting in their accumulation in water,food,and air,and abosorbed by humans via ingestion and inhalation.On the other hand,accumulation of PFAS in the human body is proving to be associated with some unfavorable health outcomes,whereas the mechanisms underlying the effects of PFAS exposure on human lung diseases remain unclear at present.The toxicological effects of organic components are a significant focus of research.This review will fix our attention on the changes in the distribution,composition,and content of PFAS in PM2.5 by location and year,and provide an overview on the influence of PM2.5 and PFAS on lung health,with indications of possible synergistic adverse effects of PM2.5 and PFAS on pulmonary homeostasis.

Recent Advances in the Analytical Techniques for PFASs and Corresponding Intermediates During Their Chemical Decomposition

Per-and polyfluoroalkyl substances(PFASs)have been restricted from production and consumption in many countries due to their persistence and biological toxicity.With the development of removal technologies,the requirement on the detection of different kinds of PFASs and their derivates is increasing.A suitable analytical method is the prerequisite and basis for the study of the degradation of PFASs.As various analytical methods have been reported,questions about which one is more suitable have arisen.It is a right time to summarize the past and suggest the future.In this paper,we summarized and discussed the analytical methods applied in the chemical degradation of PFASs.We also proposed the current problems and discussed the future directions in this field.

Emerging contaminants in biosolids:Presence,fate and analytical techniques

Emerging contaminants(ECs)represent a small fraction of the large chemical pollution puzzle where a wide variety of potentially hazardous chemicals reach the environment,and new compounds are continuously synthesized and released in wastewater treatment plants and ultimately in effluent and biosolids.ECs have been classified into various categories;however,this article focuses on the fate of major categories,namely pharmaceutical and personal care products(PPCPs),per-and poly-fluoroalkyl substances(PFAS),flame retardants,surfactants,endocrine-disrupting chemicals(EDCs),and microplastics(MPs).These ECs when discharged to sewer and downstream wastewater treatment plants can undergo further transformations and either degrade,persist or convert into by-products which have the potential in some cases to be more hazardous.Because of potential dangerous impacts of the availability of these contaminants in the environment,information on the fate and behavior of these pollutants is highly important to develop new strategies,such as the regulation of chemicals imported into Australia and Australian consumer goods and environmental policies to mitigate them in a sustainable way.Moreover,advanced technologies are required for the detection and identification of novel contaminants emerging in the environment at ultra low levels.The application of chromatographic techniques coupled with mass spectroscopy has provided attractive breakthroughs to detect new emerging contaminants.However,it is crucially important to understand the sensitivity and robustness of these analytical techniques when dealing with complex matrices such as biosolids.In addition,most of the literature was focused on selected compounds or a family of compounds and the existing reviews have paid less attention to examine the formation of metabolites during the wastewater treatment process and their impacts on the ecosystem.This review presents an overview of the presence of different classes of ECs around the world,their quantification from different sources like wastewater(influents or effluents),sludge and biosolids.In addition,the transformation of ECs during the treatment process,the formation of intermediate products and their impacts on the environment are also critically discussed.Three major steps of ECs analysis include sample preparation,extraction and clean-up,and analysis;hence,different methods employed for extraction and clean-up,and analytical techniques for identification are thoroughly discussed,their advantages and limitations are also highlighted.This comprehensive review article is believed to enhance the understanding of ECs in sewage sludge and would be useful to the readers of the relevant communities and various stakeholders to investigate potential technologies to maximize destruction of ECs.

Non-conventional sorption materials for the removal of legacy and emerging PFAS from water:A review

Per-and polyfluoroalkyl substances(PFAS)are a class of ubiquitous,persistent,and hazardous pollutants that raise concerns for human health and the environment.Typically,PFAS removal from water relies on adsorption techniques using conventional sorption materials like activated carbons(ACs)and ion exchange resins(IERs).However,there is a continuous search for more efficient and performing adsorbent materials to better address the wide range of chemical structures of PFAS in the environment,to increase their selectivity,and to achieve an overall high adsorption capacity and faster uptake kinetics.In this context,results from the application of non-conventional sorption materials(i.e.,readily available biological-based materials like proteins and advanced materials like nanocomposites and cyclodextrins)are reported and discussed in consideration of the following criteria:i)removal efficiency and kinetics of legacy PFAS(e.g.,PFOA,PFBA)as well as newly-introduced and emerging PFAS(e.g.,GenX),ii)representativity of environmental conditions in the experimental setup(e.g.,use of environmentally relevant experimental concentrations),iii)regenerability,reusability and applicability of the materials,and iv)role of the material modifications on PFAS adsorption.From this review,it emerged that organic frameworks,nano(ligno)cellulosic-based materials,and layered double hydroxides are among the most promising materials herein investigated for PFAS adsorption,and it was also observed that the presence of fluorine-and amine-moieties in the material structure improve both the selectivity and PFAS uptake.However,the lack of data on their applicability in real environments and the costs involved means that this research is still in its infancy and need further investigation.