Quantification of perfluorinated compounds in atmospheric particulate shows potential connection with environmental event

A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.

Recent advances in electrochemical decontamination of perfluorinated compounds from water: a review

Per- and polyfluoroalkyl substances (PFAS) pose serious human health and environmental risks due to their persistence and toxicity. Among the available PFAS remediation options, the electrochemical approach is promising with better control. In this review, recent advances in the decontamination of PFAS from water using several state-of-the-art electrochemical strategies, including electro-oxidation, electro-adsorption, and electro-coagulation, were systematically reviewed. We aimed to elucidate their design principles, underlying working mechanisms, and the effects of operation factors (e.g., solution pH, applied voltage, and reactor configuration). The recent developments of innovative electrochemical systems and novel electrode materials were highlighted. In addition, the development of coupled processes that could overcome the shortcomings of low efficiency and high energy consumption of conventional electrochemical systems was also emphasized. This review identified several major knowledge gaps and challenges in the scalability and adaptability of efficient electrochemical systems for PFAS remediation. Materials science and system design developments are forging a path toward sustainable treatment of PFAS-contaminated water through electrochemical technologies.

Evaluation of perfluorinated compounds in seven wastewater treatment plants in Beijing urban areas

The presence of perfluorinated compounds(PFCs)in seven major wastewater treatment plants(WWTPs)in Beijing was investigated in the current study.We detected nine PFCs in all the wastewater and sludge samples.Perfluorooctane acid(PFOA)is the dominant PFCs in influents and effluents,while perfluorooctane sulfonate(PFOS)is the major contaminant in sludge.The highest PFC concentration was found in plants at Qinghe and Jiuxianqiao WWTP,while the lowest was found at Fangzhuang WWTP.The total values of PFC range from 2.88 to 176 ng/L in influents,from 5.48 to 498 ng/L in effluents,and from 1.21 to 32.0 ng/g(dry wt)in sludge.The fact that effluents usually contain higher levels of PFCs than influents suggests that additional PFCs are produced during the wastewater treatment processes.However,PFOS decreases in effluents than in influents in 62%of the water samples.This may be due to the adsorption and removal of the sludge during the active process.Perfluoroalkyl carboxylates(PFCAs)were found significantly correlated with each other in the effluents,which may indicate their similar sources or the existence of their potential precursors in the wastewater or treatment processes.The mass flows of PFC discharges into WWTPs are 0.4–51.4 mg/day,and the mass flows of PFCs in effluents exceed those in influents by 127%.Domestic and commercial wastewaters are suggested to be the major sources of PFC pollution in WWTPs in Beijing.

Perfluorinated compounds in blood of textile workers and barbers

12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS） and perfluorooctanoate（PFOA） were the most prominent PFCs, with average concentrations of 5.73 mg/L and 5.46 mg/L for textile workers, and 2.55 mg/L and 2.84 mg/L for barbers.PFOS and perfluorohexanesulfonate（PFHxS） concentrations revealed a positive correlation in blood samples（p 〈 0.01）, and concentrations among PFOS, perfluorononanoic acid（PFNA） and perfluorodecanoic acid（PFDA） also revealed positive correlations（p 〈 0.01）. The influence of gender and age on PFC concentration in blood was also investigated, and the results showed that there was no statistically significant difference between the male and female samples, as well as in samples from people with different ages. Generally speaking, the textile workers

Effect of co-existing organic compounds on adsorption of perfluorinated compounds onto carbon nanotubes

Co-existing organic compounds may affect the adsorption of perfluorinated compounds （PFCs） and carbon nanotubes in aquatic environments. Adsorption of perfluorooctane sulfonate （PFOS）, perfluorooctane acid （PFOA）, perfluorobutane sulfonate （PFBS）, and perfluor- ohexane sulfonate （PFHxS） on the pristine multi-walled carbon nanotubes （MWCNTs-Pri）, carboxyl functionalized MWCNTs （MWCTNs-COOH）, and hydroxyl functiona- lized MWCNTs （MWCNTs-OH） in the presence of humic acid, 1-naphthol, phenol, and benzoic acid was studied. Adsorption kinetics of PFOS was described well by the pseudo-second-order model and the sorption equilibrium was almost reached within 24 h. The effect of co-existing organic compounds on PFOS adsorption followed the decreasing order of humic acid 〉 1-naphthol 〉 benzoic acid〉phenol. Adsorbed amounts of PFOS decreased significantly in the presence of co-existing or preloaded humic acid, and both adsorption energy and effective adsorption sites on the three MWCNTs decreased, resulting in the decrease of PFOS adsorption. With increasing pH, PFOS removal by three MWCNTs decreased in the presence of humic acid and phenol. The adsorbed amounts of different PFCs on the MWCNTs increased in the order ofPFBS 〈 PFHxS 〈 PFOA 〈 PFOS. The increase of both initial concentrations and the number of aromatic rings of co-existing organic compounds suppressed PFOS adsorption on the MWCNTs.

Process simulation and economic analysis of reactor systems for perfluorinated compounds abatement without HF effluent

New and efficient proposed to treat perfluorinated reactor systems were compounds via catalytic decomposition. One system has a single reactor （S-1）, and another has a series of reactors （S-2）. Both systems are capable of producing a valuable CaF2 and eliminating toxic HF effluent and their feasibility was studied at various temperatures with a commercial process simulator, Aspen HYSYS. They are better than the conventional system, and S-2 is better than S-1 in terms of CaF2 production, a required heat for the system, natural gas usage and CO2 emissions in a boiler, and energy consumption. Based on process simulation results, preliminary economic analysis shows that cost savings of 12.37% and 13.55% were obtained in S-2 at 589.6 and 621.4℃compared to S-1 at 700 and 750 ℃, respectively, for the same amount of CaF2 production.

Occurrence of pharmaceuticals and perfluorinated compounds and evaluation of the availability of reclaimed water in Kinmen

Emerging contaminants have commonly been observed in environmental waters but have not been included in water quality assessments at many locations around the world.To evaluate the availability of reclaimed water in Kinmen,Taiwan,this study provides the first survey of the distribution of thirty-three pharmaceuticals and five perfluorinated chemicals in lake waters and water from local wastewater treatment plants(WWTPs).The results showed that the target emerging contaminants in Kinmen lakes were at trace ng/L concentrations.In addition,most of the target compounds were present in the Jincheng and Taihu WWTP influents at ng/L concentrations levels,of which 5 compounds(erythromycin-H2O(1340 ng/L),ibuprofen(1763 ng/L),atenolol(1634 ng/L),acetaminophen(2143 ng/L),and caffeine(3113 ng/L))reached mg/L concentrations.The overall treatment efficiencies of the Jincheng and Taihu WWTPs with respect to these pharmaceuticals and perfluorinated chemicals were poor;half of the compounds were less than 50%removed.Five compounds(sulfamethoxazole,erythromycin-H2O,clarithromycin,ciprofloxacin and ofloxacin)with risk quotient(RQ)values>1 in the effluent should be further investigated to understand their effects on the aquatic environment.Additional and advanced treatment units are found necessary to provide high-quality recycled water and sustainable water resources.

Distribution characteristics of poly-and perfluoroalkyl substances in the Yangtze River Delta

In this work, a method was developed and optimized for the analysis of polyfluoroalkyl and/or perfluoroalkyl substances（PFASs） content in surface water and sediment samples with high instrumental response and good separation. Surface water and sediment samples were collected from the Yangtze River Delta（YRD） to analyze the distribution characteristics of perfluoroalkyl carboxylic acids（PFCAs）, perfluoroalkane sulfonic acids（PFSAs）, perfluoroalkyl phosphonic acids（PFPAs）, perfluoroalkyl phosphinic acids（PFPiAs）, and polyfluoroalkyl phosphoric acid diesters（di PAPs）. The results showed that the total concentrations of PFCAs and PFSAs in YRD varied from 31 to 902 ng/L. PFCAs（≥ 11 carbons） and PFSAs（≥ 10 carbons atoms） were not detected in any surface water samples. The mean concentrations of all PFCAs and PFSAs in surface water from the sampling areas decreased in the following order：Yangtze river（191 ng/L） ≈ Taihu lake（189 ng/L） 〉 Huangpu river（122 ng/L） ≈ Qiantang river（120 ng/L） 〉 Jiaxing urban river（100 ng/L）. Strong significant（p 〈 0.05） correlations between the concentrations of many of the compounds were found in the sampling areas, suggesting a common source for these compounds. Only perfluorooctanoic acid（PFOA） was observed in all sediment samples, at concentrations varying from 0.02 to 1.35 ng/g. Finally, detection rates of two di PAPs were only 8% and 10%, respectively and the concentration of di PAPs was two to three times lower compared to PFCAs and PFSAs.

Effects of pH on photochemical decomposition of perfluorooctanoic acid in different atmospheres by 185 nm vacuum ultraviolet

Perfluorooctanoic acid （PFOA）, a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by 185 nm vacuum ultraviolet （VUV） is one of the efficient methods for PFOA decomposition. The effects of pH on PFOA decomposition in nitrogen atmosphere or oxygen atmosphere were investigated. At its original pH （4.5） of PFOA aqueous solution, PFOA decomposed efficiently both in nitrogen and in oxygen atmosphere. However, when the pH increased to 12.0, PFOA decomposition was greatly inhibited in oxygen atmosphere, while it was greatly accelerated in nitrogen atmosphere with a very short half-life time （9 rain）. Furthermore, fluorine atoms originally contained in PFOA molecules were almost completely transformed into fluoride ions. Two decomposi- tion pathways have been proposed to explain the PFOA decomposition under different conditions. In acidic and neutral solutions, PFOA predominantly decomposes via the direct photolysis in both atmospheres; while in the alkaline solution and in the absence of oxygen, the decomposition of PFOA is mainly induced by hydrated electrons.