Polyfluorinated Chemicals Research Articles

A prescription for engineering PFAS biodegradation.

Per- and polyfluorinated chemicals (PFAS) are of rising concern due to environmental persistence and emerging evidence of health risks to humans. Environmental persistence is largely attributed to a failure of microbes to degrade PFAS. PFAS recalcitrance has been proposed to result from chemistry, specifically C-F bond strength, or biology, largely negative selection from fluoride toxicity. Given natural evolution has many hurdles, this review advocates for a strategy of laboratory engineering and evolution. Enzymes identified to participate in defluorination reactions have been discovered in all Enzyme Commission classes, providing a palette for metabolic engineering. In vivo PFAS biodegradation will require multiple types of reactions and powerful fluoride mitigation mechanisms to act in concert. The necessary steps are to: (1) engineer bacteria that survive very high, unnatural levels of fluoride, (2) design, evolve, and screen for enzymes that cleave C-F bonds in a broader array of substrates, and (3) create overall physiological conditions that make for positive selective pressure with PFAS substrates.

Toxic Components of Plastic Pose Carcinogenic Threat to Public Health

The toxicity of plastics and its components is increasing day by day for human needs. In modern days, plastics are widely used in every product in our daily life. In 2021, it was predicted that the world would produce 390.7 million metric tons of plastic. A year's worth of plastic waste is produced in India at 3.4 million tons. Many products are manufactured with plastic due to its impressive characteristics such as inert, flexibility, durability, versatility, lightweight, and less costly. They encourage dangers to the planet and human health. Numerous chemical and toxic contaminants, including Bisphenol A (BPA), phthalates, antimonitroxide, brominated flame retardants, poly-fluorinated chemicals, nonylphenol, polychlorinated biphenylethers, dichlorodiphenyldichloroethylene, phenanthrene, among others, are found in plastics and pose a major risk to human health and the environment. These chemical and hazardous compounds are used in the manufacturing of plastic bottles, containers, pharmaceuticals, food packaging, baby toys, etc. The impact of plastics on the environment gets more dangerous day by day. Not only the environment but also exposure to plastics leads to various human health risks. Toxic components of plastics lead to several serious cancers even;they are also possessing their genotoxic effects on human health. This review contains the toxicity of plastic components on human health and the environment by low-level exposure and gives a proper awareness about the health problems and focuses on degrading ways to reduce its effects.

Perfluorooctanoic acid in the sediment matrices of Arctic fjords, Svalbard

Per- and polyfluorinated chemicals (PFASs) are very toxic industrial compounds, and fewer studies have been conducted on their presence in the sedimentary environment of the polar region. The present study is a preliminary assessment of the concentration and distribution of PFOA (Perfluorooctanoic acid) in selected fjord systems of the Svalbard archipelago, Norwegian Arctic. The ∑PFOA observed for Smeerenburgfjorden, Krossfjorden, Kongsfjorden Hotmiltonbuktafjorden, Raudfjorden and Magdalenefjorden were 1.28 ng/g, 0.14 ng/g, 0.68 ng/g, 6.54 ng/g, 0.41 ng/g and BDL respectively. Of the twenty-three fjord samples studied, the sediments from Hotmiltonbuktafjorden exhibited the presence of a higher concentration of PFOA in the sediment matrices. More studies are needed to understand their fate in the sedimentary environment with respect to the physio-chemical properties of the sediments.

Evaluation of Process Wise ZDHC MRSL Conformance Status of Bangladesh RMG Sector

The ZDHC Roadmap to Zero Program is a coalition of fashion brands, value chain affiliates and associates empowering the global textile, leather, apparel, and footwear value chain to substitute hazardous chemicals for safer ones in the production process. ZDHC takes a holistic, open approach, supporting safer chemical management practices across the entire value chain. By collaborating with ZDHC, organizations can mitigate risk, respond to changing customer demands, cut costs, and preserve valuable resources. Tools like CleanChain, BHIVE, BVE3 help to reduce costs and the administrative burden of collecting supply chain data by performing qualitative & quantitative analysis of chemicals. CleanChain, an ADEC Innovation, helps to automate the complex tasks of tracking, managing, and reporting compliance with Manufacturing Restricted Substance Lists (MRSLs) and Restricted Substances Lists (RSLs). In this research my objective is to identify the qualitative & quantitative analysis for the following groups of chemicals used in the different process like Alkylphenol (AP) and Alkylphenol Ethoxylates (APEOs): Including All Isomers, Anti- Microbials & Biocides, Chlorinated Paraffins, Chlorobenzenes and Chlorotoluene, Chlorophenols, Dimethyl Formamide (DMFa), Dyes – Carcinogenic or Equivalent Concern, Dyes – Disperse (Sensitizing), Dyes – Navy Blue Colorants, Flame Retardants, Glycols / Glycol Ethers, Halogenated Solvents, Organotin Compounds, Other/Miscellaneous Chemicals, Perfluorinated and Polyfluorinated Chemicals (PFCs), Phthalates – including all other esters of ortho-phthalic acid, Polycyclic Aromatic Hydrocarbons (PAHs), Restricted Aromatic Amines (Cleavable from Azo-colorants), UV Absorbers, Volatile Organic Compounds (VOC) & the impact of the un evaluated chemical which may have the following impact like Skin irritant/skin sensitizer/eye irritant Carcinogenic, mutagenic, reprotoxic Endocrine disruptors, Persistent, bio accumulative, toxic to aquatic life, Specific target organ toxic, Respiratory sensitizer, Acute toxic through oral, dermal or inhalation route, Developmental toxin/neurotoxin/impact on the central nervous system.

Dual-Functional Phosphorene Nanocomposite Membranes for the Treatment of Perfluorinated Water: An Investigation of Perfluorooctanoic Acid Removal via Filtration Combined with Ultraviolet Irradiation or Oxygenation.

Nanomaterials with tunable properties show promise because of their size-dependent electronic structure and controllable physical properties. The purpose of this research was to develop and validate environmentally safe nanomaterial-based approach for treatment of drinking water including removal and degradation of per- and polyfluorinated chemicals (PFAS). PFAS are surfactant chemicals with broad uses that are now recognized as contaminants with a significant risk to human health. They are commonly used in household and industrial products. They are extremely persistent in the environment because they possess both hydrophobic fluorine-saturated carbon chains and hydrophilic functional groups, along with being oleophobic. Traditional drinking water treatment technologies are usually ineffective for the removal of PFAS from contaminated waters, because they are normally present in exiguous concentrations and have unique properties that make them persistent. Therefore, there is a critical need for safe and efficient remediation methods for PFAS, particularly in drinking water. The proposed novel approach has also a potential application for decreasing PFAS background levels in analytical systems. In this study, nanocomposite membranes composed of sulfonated poly ether ether ketone (SPEEK) and two-dimensional phosphorene were fabricated, and they obtained on average 99% rejection of perfluorooctanoic acid (PFOA) alongside with a 99% removal from the PFOA that accumulated on surface of the membrane. The removal of PFOA accumulated on the membrane surface achieved 99% after the membranes were treated with ultraviolet (UV) photolysis and liquid aerobic oxidation.

Freshwater amphipods (Gammarus pulex/fossarum) and brown trout as bioindicators for PFC contamination with regard to the aquatic ecological status of a small stream

BackgroundPer- and polyfluorinated chemicals (PFC) have been in use for more than 60 years. As a result of their high thermal and chemical stability, they have found numerous applications in industrial processes. However, PFC also commonly show disadvantageous properties such as persistence and ubiquitous presence in the environment. The issue of PFC contamination of surface water is addressed in this publication. One aim of this study was to find a potential bioindicator for PFC contamination of small streams, and a second aim was to determine the aquatic ecological quality of such a stream. Standardized methods were used including structural quality mapping of a watercourse, the PERLODES method and electrofishing in four study sections of the stream. PFC contamination was determined in freshwater amphipods (Gammarus pulex/fossarum) and brown trout.ResultsThis study shows that PFC originating from water contamination can be detected both in amphipods and in internal organs of brown trout. The fingerprints in these two species differ considerably from one another. The highest concentrations of PFC were found in the liver and kidneys of brown trout. The methods used in this study also show that the four study sections of the small stream tested fail to achieve the “good” ecological status required by the Water Framework Directive. In particular, this is due to inadequate benthic invertebrates.ConclusionsEven though it is not possible to determine a causal relationship between the ecological status of the small stream and the detection of PFC in aquatic organisms, appropriate measures must be developed and applied to reduce the spreading of PFC in the environment. In addition to the brown trout, freshwater amphipods proved to be useful as a bioindicator for PFC contamination of streams. In the future it will be necessary to observe whether the number of species in the benthic invertebrates continue to decline.

EPA recommends cleanup level for PFOS and PFOA in groundwater

With a number of caveats, the US Environmental Protection Agency is recommending the cleanup of groundwater tainted with more than 70 parts per trillion of either of two widespread polyfluorinated chemicals. The EPA’s April 25 draft interim recommendations would apply only to groundwater that is a current or potential source of drinking water and would not have the legal force of regulations. They would also apply only in states that lack what the agency deems an “appropriate” drinking-water standard for the two chemicals, perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS). The recommendations follow the EPA’s 2016 health advisory limit of 70 ppt for PFOS and PFOA, individually or combined, in drinking water. The two substances, which are no longer commercially produced in the US, contaminate groundwater across the nation and the world. In many areas, the pollution stems from military bases and airports that for years used firefighting foams containing

Per- and poly-fluoroalkyl compounds in freshwater fish from the Rhône River: Influence of fish size, diet, prey contamination and biotransformation

Pools of aquatic plants and benthic invertebrates were collected along with 47 individuals from three cyprinid fish species (Barbus barbus, Gobio gobio, Rutilus rutilus) at a site in the Rhône River (France). Carbon and nitrogen isotopic ratios (δ13C and δ15N) and a wide range of per- and poly-fluorinated chemicals (PFASs) were analysed in all samples. The sum of PFAS concentrations (ΣPFAS) increased from aquatic plants to fish dorsal muscles; molecular profiles were dominated by C9–C13 perfluorocarboxylic acids (PFCAs), while perfluorooctane sulfonate (PFOS) and perfluorooctane sulfonamide (FOSA) were detected in all samples at lower concentrations. ΣPFAS and especially ΣPFCAs were higher in barbels (B. barbus) than in other species, while roaches (R. rutilus) were less contaminated by PFOS than barbels and gudgeons (G. gobio). Gudgeons accumulated significantly higher FOSA concentrations. Young (small) barbels displayed significantly higher PFOS, perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) concentrations than did large specimens; conversely, perfluorotetradecanoic acid (PFTeDA) concentrations were significantly higher in large barbels. Multiple linear regressions were performed on the whole set of fish samples with size, mass and isotopic ratios as explicative variables, and several single compounds as explained variables. Regardless of the compound, the regressions did not explain much of the contamination variability. However, adding species as a qualitative variable, i.e. performing analyses of covariance (ANCOVAs) improved the fit greatly, while adding sex did not. Diet (i.e. δ13C and δ15N) was the main factor explaining interspecific differences. Biotransformation was assessed by comparing concentration ratios of PFOS or FOSA to their precursors in the food-web compartments. These ratios increased from invertebrates to fish, and differed among fish species, suggesting that biotransformation occurred but was species-specific. Biomagnification factor calculations showed that C11–C13 PFCAs, PFOS and FOSA were apparently biomagnified in barbels and gudgeons.

Determination of adsorbable organic fluorine from aqueous environmental samples by adsorption to polystyrene-divinylbenzene based activated carbon and combustion ion chromatography

A new method for the determination of trace levels of adsorbable organic fluorine (AOF) in water is presented. Even if the individual contributing target compounds are widely unknown, this surrogate parameter is suited to identify typical organofluorine contaminations, such as with polyfluorinated chemicals (PFCs), and represents a lower boundary of the organofluorine concentration in water bodies. It consists of the adsorption of organofluorine chemicals on a commercially available synthetic polystyrene-divinylbenzene based activated carbon (AC) followed by analysis of the loaded AC by hydropyrolysis combustion ion chromatography (CIC). Inorganic fluorine is displaced by excess nitrate during the extraction step and by washing the loaded activated carbon with an acidic sodium nitrate solution. Due to its high purity the synthetic AC had a very low and reproducible fluorine blank (0.3μg/g) compared to natural ACs (up to approximately 9μg/g). Using this AC, fluoride and the internal standard phosphate could be detected free of chromatographic interferences. With a sample volume of 100mL and 2× 100mg of AC packed into two extraction columns combined in series, a limit of quantification (LOQ), derived according to the German standard method DIN 32645, of 0.3μg/L was achieved. The recoveries of six model PFCs were determined from tap water and a municipal wastewater treatment plant (WWTP) effluent. Except for the extremely polar perfluoroacetic acid (recovery of approximately 10%) the model substances showed fairly good (50% for perfluorobutanoic acid (PFBA)) to very good fluorine recoveries (100±20% for perfluorooctanoic acid (PFOA), perfluorobutanesulfonate (PFBS), 6:2 fluorotelomersulfonate (6:2 FTS)), both from tap water and wastewater matrix. This new analytical protocol was exemplarily applied to several surface water and groundwater samples. The obtained AOF values were compared to the fluorine content of 19 target PFCs analyzed by high performance liquid chromatography–electrospray tandem mass spectrometry (HPLC–(−)ESI-MS/MS). In groundwater contaminated by PFC-containing aqueous film-forming foams (AFFFs) up to 50% of the AOF could be attributed to PFC target chemicals, while in diffuse contaminated samples only <5% of the AOF could be identified by PFC analysis.

Perfluorooctanoic acid (PFOA) — main concerns and regulatory developments in Europe from an environmental point of view

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the most investigated substances of the group of per- and polyfluorinated chemicals (PFCs). Whereas for PFOS regulatory measures are already in force on international level (inclusion in Stockholm Convention on Persistent Organic Pollutants) such activities are missing for PFOA. The environmental concerns of PFOA, which are summarized in the present study, underline the necessity of regulatory measures on an international level for PFOA. Since it seems more likely to agree on a regulation within the European Union first, a regulatory strategy based on the European chemicals regulation REACH (EC No. 1907/2006), is discussed in the present study. PFOA is persistent in the environment, ubiquitous present in surface waters, and subject to long-range transport. It accumulates in biota, especially in top predators. PFOA is increasingly analyzed in food items, and in drinking water. PFOA’s intrinsic properties such as its persistency (P), its potential for bioaccumulation (B) and its toxicity (T) suggest that PFOA is a promising candidate for being identified as a Substance of Very High Concern (SVHC) under REACH. Because of the dispersive occurrence of PFOA in the environment, the presence in imported products, and the use of PFCs, which can degrade to PFOA in various consumer products, a restriction under REACH seems to be the most effective regulatory measure to minimize human and environmental exposure to PFOA in the European Union. Due to its intrinsic properties, PFOA fulfills the REACH PBT-criteria. The next regulatory step will be the identification of PFOA and its ammonium salt (APFO) as SVHC according to REACH and the addition to the REACH Candidate List. As a second step, a restriction proposal will be prepared to include both substances and precursors into REACH Annex XVII.

CADASTER QSPR Models for Predictions of Melting and Boiling Points of Perfluorinated Chemicals.

Quantitative structure property relationship (QSPR) studies on per- and polyfluorinated chemicals (PFCs) on melting point (MP) and boiling point (BP) are presented. The training and prediction chemicals used for developing and validating the models were selected from Syracuse PhysProp database and literatures. The available experimental data sets were split in two different ways: a) random selection on response value, and b) structural similarity verified by self-organizing-map (SOM), in order to propose reliable predictive models, developed only on the training sets and externally verified on the prediction sets. Individual linear and non-linear approaches based models developed by different CADASTER partners on 0D-2D Dragon descriptors, E-state descriptors and fragment based descriptors as well as consensus model and their predictions are presented. In addition, the predictive performance of the developed models was verified on a blind external validation set (EV-set) prepared using PERFORCE database on 15 MP and 25 BP data respectively. This database contains only long chain perfluoro-alkylated chemicals, particularly monitored by regulatory agencies like US-EPA and EU-REACH. QSPR models with internal and external validation on two different external prediction/validation sets and study of applicability-domain highlighting the robustness and high accuracy of the models are discussed. Finally, MPs for additional 303 PFCs and BPs for 271 PFCs were predicted for which experimental measurements are unknown.

Oral LD50 toxicity modeling and prediction of per- and polyfluorinated chemicals on rat and mouse

Quantitative structure-activity relationship (QSAR) analyses were performed using the LD(50) oral toxicity data of per- and polyfluorinated chemicals (PFCs) on rodents: rat and mouse. PFCs are studied under the EU project CADASTER which uses the available experimental data for prediction and prioritization of toxic chemicals for risk assessment by using the in silico tools. The methodology presented here applies chemometrical analysis on the existing experimental data and predicts the toxicity of new compounds. QSAR analyses were performed on the available 58 mouse and 50 rat LD(50) oral data using multiple linear regression (MLR) based on theoretical molecular descriptors selected by genetic algorithm (GA). Training and prediction sets were prepared a priori from available experimental datasets in terms of structure and response. These sets were used to derive statistically robust and predictive (both internally and externally) models. The structural applicability domain (AD) of the models were verified on 376 per- and polyfluorinated chemicals including those in REACH preregistration list. The rat and mouse endpoints were predicted by each model for the studied compounds, and finally 30 compounds, all perfluorinated, were prioritized as most important for experimental toxicity analysis under the project. In addition, cumulative study on compounds within the AD of all four models, including two earlier published models on LC(50) rodent analysis was studied and the cumulative toxicity trend was observed using principal component analysis (PCA). The similarities and the differences observed in terms of descriptors and chemical/mechanistic meaning encoded by descriptors to prioritize the most toxic compounds are highlighted.

Comparison of two extraction methods for the analysis of per- and polyfluorinated chemicals in digested sewage sludge

A rapid and reliable analytical method, based on ion-pair extraction, clean-up on Envicarb cartridge and detection by liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for determination of 17 per- and polyfluorinated chemicals (PFCs) in digested sewage sludge. Envicarb cartridge and six labeled internal standards were selected for the elimination/reduction and correction of matrix effects, respectively. As a result, the matrix effect for perfluorooctane sulfonamides (FOSAs) and perfluorocarboxylic acids (PFCAs) with carbon chain length from C6 to C14 was lowered to a range of −14% to +28%. However, the matrix effect for other analytes was still great mainly due to the absence of appropriate internal standard. Mean recoveries of the target analytes based on matrix spikes, at different spike levels (10–300 ng/g), ranged from 70% to 169%. Relative standard deviations (RSDs) were in the range of 2–20% at different spike levels. The limit of quantification (LOQ) ranged between 0.6 and 30 ng/g. The method was successfully applied to several sewage sludge samples from wastewater treatment plants nearby Zürich, Switzerland. In addition, by comparing the accuracy and precision of ion-pair extraction method and methanol extraction method, we further demonstrated that the ion-pair extraction method can be used for the analysis of PFCs in sludge samples. To our knowledge, this is the first study to extract the PFCs in sewage sludge with ion-pair method and to find unsaturated fluorotelomer carboxylic acids (FTUCAs) in sewage sludge.

Survey of polyfluorinated chemicals (PFCs) in the atmosphere over the northeast Atlantic Ocean

High volume air sampling in Bermuda, Sable Island (Nova Scotia) and along a cruise track from the Gulf of Mexico to northeast coast of the USA, was carried out to assess air concentrations, particle-gas partitioning and transport of polyfluorinated chemicals (PFCs) in this region. Samples were collected in the summer of 2007. Targeted compounds included the neutral PFCs: fluorotelomer alcohols (FTOHs), perfluoroalkyl sulfonamides (FOSAs) and perfluoroalkyl sulfonamido ethanols (FOSEs). Among the FTOHs, 8:2 FTOH was dominant in all samples. Sum of the concentration of FTOHs (gas+particle phase) were higher in Bermuda (mean, 34 pg m −3) compared to Sable Island (mean, 16 pg m −3). In cruise samples, sum of FTOHs were highly variable (mean, 81 pg m −3) reflecting contributions from land-based sources in the northeast USA with concentrations reaching as high as 156 pg m −3. Among the FOSAs and FOSEs, MeFOSE was dominant in all samples. In Bermuda, levels of MeFOSE were exceptionally high (mean, 62 pg m −3), exceeding the FTOHs. Sable Island samples also exhibited the dominance of MeFOSE but at a lower concentration (mean, 15 pg m −3). MeFOSE air concentrations (pg m −3) in cruise samples ranged from 1.6 to 73 and were not linked to land-based sources. In fact high concentrations of MeFOSE observed in Bermuda were associated with air masses that originated over the Atlantic Ocean. The partitioning to particles for 8:2 FTOH, 10:2 FTOH, MeFOSE and EtFOSE ranged from as high as 15 to 42% for cruise samples to 0.9 to 14% in Bermuda. This study provides key information for validating and developing partitioning and transport models for the PFCs.

Emerging endocrine disrupters: perfluoroalkylated substances

In recent years, polyfluorinated chemicals (PFCs) have increasingly been used as surfactants in various industry- and consumer products, because of their unique properties as repellents of dirt, water and oils. The most well-known PFCs are perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and their derivatives belonging to the group of perfluoroalkylated substances. The PFCs are very persistent in the environment, and some of them have been discovered as global pollutants of air, water, soil and wildlife and even found in remote polar areas. Bioaccumulation occurs also in humans, and everybody in our society has traces of these PFCs in their blood and internal organs such as the liver, kidneys, spleen, gall bladder and testes. In the blood, PFOS and PFOA are bound to serum proteins. The acute toxicity of the polyfluorinated substances is moderate but some substances can induce peroxisome proliferation in rat livers and may change the fluidity of cell membranes. Some of these PFCs, such as PFOS and PFOA, are potential developmental toxicants and are suspected endocrine disruptors with effects on sex hormone levels resulting in lower testosterone levels and higher oestradiol level. Other PFCs have oestrogenic effects in cell cultures. The industrial production of PFOS and its derivatives stopped in 2000, and the European Union has banned most uses from the summer of 2008. However, hundreds of related chemicals: homologues with shorter or longer alkyl chain, PFOA and telomers, which potentially may degrade to perfluoroalkanoic (carboxylic) acids, are not regulated.

Sorbent-Impregnated Polyurethane Foam Disk for Passive Air Sampling of Volatile Fluorinated Chemicals

A passive air sampler comprising a polyurethane foam (PUF) disk impregnated with XAD-4 powder has been developed. This sorbent-impregnated PUF (SIP) disk builds on previous work using PUF disk passive air samplers that have been effective in spatial air mapping studies of nonpolar hydrophobic chemicals, without the need of electricity or expensive air sampling equipment. In this study, PUF disks and SIP disks are calibrated for sampling volatile polyfluorinated chemicals--specifically, the fluorotelomer alcohols (FTOHs) and perfluoroalkyl sulfonamides (PFASs). Results demonstrate the low sorptive capacity of the PUF disk samplers, particularly for the FTOHs, with PUF disks reaching equilibrium within 1 day, after collecting approximately 0.4 and 1.2 m3 of air for 8:2 FTOH and 10:2 FTOH, respectively. This limits their use for these target compounds when time-weighted, linear-phase sampling is desired. The presence of just 0.4 g of XAD powder in the SIP disks greatly increases the sorptive capacity (by approximately 2 orders of magnitude for the FTOHs) and provides linear-phase sampling for a period of several weeks. PUF-air partition coefficients, KPUF-A, calculated for the FTOHs and PFASs are considerably lower than values predicted using previously established correlations against the octanol-air partition coefficient, KOA, demonstrating the unique partitioning behavior of the polyfluorinated chemicals. Using results from these calibration tests, air concentrations of FTOHs were derived from PUF disk samples that were deployed in 52 homes in Ottawa, Canada, during 2002/2003. These represent the first comprehensive measurements of FTOHs in indoor air in North America. Range and (geometric mean) air concentrations (pg m-3) were 261-28 900 (2070) for 8:2 FTOH and 104-9210 (890) for 10:2 FTOH. These air concentrations are orders of magnitude higher than observed for outdoor air, establishing indoor environments as important for human exposure and also as potential sources to the larger environment.