Reviewing the current state of legacy POP-brominated flame retardants in plastic childcare products and toys: a scoping review protocol.

BACKGROUND: Due to their adverse environmental and health impacts, brominated flame retardants (BFRs) are listed in Annex A of the Stockholm Convention for global elimination of production and use. Their health impacts include endocrine disruption, cancer, reproductive effects, and neurobehavioral and developmental disorders in children. Emerging literature suggests that legacy POP-BFRs are increasingly found in consumer products, including those used for and by children. The presence of legacy POP-BFRs in children's products is a big concern. Children are more vulnerable to chemical exposure risks than adults because their bodies are still developing and fragile. The rising problem is contributed to by the global push towards a circular economy that encourages responsible production and consumption by practising the recycling of waste materials. Waste materials such as electronic and electrical equipment plastics often contain POP-BFRs. POP-BFRs in waste materials are transferred into new products through recycling. The recycled products have become a potential source of exposure to legacy POP-BFRs for vulnerable populations, particularly children. Our scoping review aims to map and summarise the emerging literature. This information is needed to inform evidence-based policies to protect children from toxic exposures. METHODS: Our scoping review will follow a methodological framework proposed by Arksey and O'Malley. Peer-reviewed and grey literature on the topic will be retrieved from electronic databases and other relevant sites. Two reviewers will screen titles and abstracts, followed by a full-text review of studies for eligibility based on the established inclusion and exclusion criteria. Data will be extracted, and findings will be mapped in a table according to study settings, types of children's products tested, and concentration of legacy POP-BFRs in contaminated products. A map chart will be created to display how contaminated products are spread globally. DISCUSSION: Because of their unique vulnerabilities, children continue to suffer disproportionate exposures to toxic chemicals compared to adults. Information on potential exposures, particularly for children, is crucial to make evidence-based policies. We intend to map and summarise the emerging literature on legacy POP-BFRs in children's products. Findings will be disseminated to relevant stakeholders through publishing in a peer-reviewed scientific journal and policy briefs. SYSTEMATIC REVIEW REGISTRATION: The protocol is registered with the Open Science Framework ( https://doi.org/10.17605/OSF.IO/7KDE5 ).

Characterizing the effects of Dechlorane Plus on ß-cells: a comparative study across models and species.

Epidemiological studies consistently link environmental toxicant exposure with increased Type 2 diabetes risk. Our study investigated the diabetogenic effects of a widely used flame retardant, Dechlorane Plus (DP), on pancreatic ß-cells using rodent and human model systems. We first examined pancreas tissues from male mice exposed daily to oral gavage of either vehicle (corn oil) or DP (10, 100, or 1000 µg/kg per day) and fed chow or high fat diet for 28-days in vivo. DP exposure did not affect islet size or endocrine cell composition in either diet group. Next, we assessed the effect of 48-hour exposure to vehicle (DMSO) or DP (1, 10, or 100 nM) in vitro using immortalized rat ß-cells (INS-1 832/3), primary mouse and human islets, and human stem-cell derived islet-like cells (SC-islets). In INS-1 832/3 cells, DP did not impact glucose-stimulated insulin secretion (GSIS) but significantly decreased intracellular insulin content. DP had no effect on GSIS in mouse islets or SC-islets but had variable effects on GSIS in human islets depending on the donor. DP alone did not affect insulin content in mouse islets, human islets, or SC-islets, but mouse islets co-exposed to DP and glucolipotoxic (GLT) stress conditions (28.7 mM glucose + 0.5 mM palmitate) had reduced insulin content compared to control conditions. Co-exposure of mouse islets to DP + GLT amplified the upregulation of Slc30a8 compared to GLT alone. Our study highlights the importance and challenges of using different in vitro models for studying chemical toxicity.

Proinflammatory microglial response is a common mechanism of Aroclor 1254- and Tetrabromobisphenol-A-induced neurotoxicity in immature chronically exposed rats.

Polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) are dominant environmental and food contaminants. Tetrabromobisphenol A (TBBPA) is the most widely used BFR in the world to improve the fire safety of laminates in electrical and electronic equipment. Aroclor 1254, one of the PCBs, is widely distributed in the environment due to its extensive use in industrial applications around the world. Both groups of substances are potent toxicants. There is also increasing evidence that they have neurotoxic effects. In this study we tested the pro-inflammatory effects of Aroclor 1254 and TBBPA based on markers of microglial reactivity and levels of pro-inflammatory factors in the brain of immature rats. Aroclor 1254 or TBBPA were administered to the rats by oral gavage for two weeks at a dose of 10 mg/kg b.w. Both light and electron microscopy studies revealed features indicative of microglia activation in brains of exposed rats. Morphological changes were associated with overexpression of pro-inflammatory enzymes such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Analysis of cytokine/chemokine array revealed significant secretion of inflammatory mediators following exposure to both TBBPA and Aroclor 1254, which was stronger in the cerebellum than in the forebrain of exposed immature rats. The results indicate a pro-inflammatory profile of microglia activation as one of the neurotoxic mechanisms of both examined toxicants.

Tris(1,3-dichloro-2-propyl) phosphate-induced cytotoxicity and its associated mechanisms in human A549 cells.

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is a widely used organophosphorus flame retardant and has been detected in various environmental matrices including indoor dust. Inhalation of indoor dust is one of the most important pathways for human exposure to TDCIPP. However, its adverse effects on human lung cells and potential impacts on respiratory toxicity are largely unknown. In the current study, human non-small cell carcinoma (A549) cells were selected as a cell model, and the effects of TDCIPP on cell viability, cell cycle, cell apoptosis, and underlying molecular mechanisms were investigated. Our data indicated a concentration-dependent decrease in the cell viability of A549 cells after exposure to TDCIPP for 48 h, with half lethal concentration (LC50) being 82.6 µM. In addition, TDCIPP caused cell cycle arrest mainly in the G0/G1 phase by down-regulating the mRNA expression of cyclin D1, CDK4, and CDK6, while up-regulating the mRNA expression of p21 and p27. In addition, cell apoptosis was induced via altering the expression levels of Bcl-2, BAX, and BAK. Our study implies that TDCIPP may pose potential health risks to the human respiratory system and its toxicity should not be neglected.

Species-specific and habitat-dependent bioaccumulation of halogenated flame retardants in marine organisms from estuary to coastal seas.

Halogenated flame retardants (HFRs) have attracted global attention owing to their adverse effects on ecosystems and humans. The Shandong Peninsula is the largest manufacturing base for HFRs in East Asia, yet its impacts on marine ecosystems are unclear. Seventeen HFRs were analyzed in organisms captured from the Xiaoqing River estuary, Bohai Sea (BS), Yellow Sea and Northern East China Sea to investigate the distribution and bioaccumulation of HFRs on a broad scale. The results showed a downward trend in ΣHFR concentrations from the estuary (37.7 ng/g lw on average) to Laizhou Bay (192 ng/g lw) and to coastal seas (3.13 ng/g lw). The concentrations of ΣHFRs were significantly higher in demersal fish (0.71-198 ng/g lw) and benthic invertebrates (0.81-3340 ng/g lw) than in pelagic fish (0.30-27.6 ng/g lw), reflecting a habitat dependence. The concentrations of higher-brominated homologs were greater in benthic invertebrates, whereas a greater level of lower-brominated PBDE congeners was observed in fish, suggesting different profiles between species. Furthermore, the analogue composition of HFRs in fish was similar to that in the dissolved phase of seawater, whereas the HFR pattern in benthic invertebrates was consistent with the profile in sediment. The concentrations of HFRs in organisms vary widely depending on emissions from anthropogenic activities, whereas bioaccumulation patterns are strongly influenced by species and habitat.

Self-assembled lignin-based flame retardant hybrids carrying Cu2+ for poly(lactic acid) composites with improved fire safety and mechanical properties.

To enhance the flame retardancy and mechanical performance of PLA, a polyelectrolyte complex predicated on lignin was obtained by electrostatic mutual adsorption of ammonium polyphosphate (APP), polyethyleneimine (PEI), and copper ions as raw materials. The FT-IR spectra and EDX analysis confirmed the successful synthesis of a lignin-based flame retardant hybrid (APL-Cu2+) containing copper, phosphorus, and nitrogen elements. The combustion test results showed that the peak heat release rate and total heat release of the PLA composite containing 12 wt% APL-Cu2+ were decreased by 15.1 % and 18.2 %, respectively, as compared to those of pure PLA. The char residue morphology observation revealed that the addition of APL-Cu2+ could promote the formation of a highly dense and stable graphitized char layer, while TG-MS detected the emission of refractory gases such as ammonia gas, carbon dioxide, and water during combustion. The strong hydrogen bonding between APL-Cu2+ and the PLA matrix kept the composite maintaining good strength and toughness. The tensile strength and impact strength of PLA/6APL-Cu2+ increased by 4.73 % and 65.71 %, respectively, due to its high crystallinity and good interfacial compatibility. This work provides a feasible method to develop biobased flame retardant hybrids for PLA composites with better fire safety and improved mechanical properties.

Dust dynamics: distribution patterns of semi-volatile organic chemicals across particle sizes in varied indoor microenvironments.

An extensive analysis of the distribution patterns of three distinct classes of semi-volatile organic chemicals (SVOCs)-phthalates (PAEs), organophosphate flame retardants (OPFRs), and polycyclic aromatic hydrocarbons (PAHs)-across four distinct size fractions of dust (25, 50, 100, and 200 µm) was conducted. The dust samples were sourced from AC filter, covered car parking lots, households, hotels, mosques, and car floors. To generate the four fractions, ten dust samples from each microenvironment were pooled and sieved utilizing sieving apparatus with the appropriate mesh size. Selected SVOCs were quantified utilizing gas chromatography-mass spectrometry in electron impact (EI) mode. Results unveiled diverse contamination levels among dust fractions, showcasing car parking lot dust with the lowest chemical contamination, while car floor dust displayed the highest levels of PAHs and OPFRs, peaking at 28.3 µg/g and 43.2 µg/g, respectively. In contrast, mosque and household floor dust exhibited the highest concentrations of phthalates, with values of 985 µg/g and 846 µg/g, respectively. Across the analyzed microenvironments, we observed a trend where concentrations of SVOCs tended to rise as dust particles decreased in size, forming a visually striking pattern. This phenomenon was particularly pronounced in dust samples collected from car floors and parking lots. Among SVOCs, PAEs emerged as the predominant contributors with > 90% followed by OPFRs and PAHs. The high levels of OPFRs in car floor dust align logically with the fact that numerous interior components of cars are treated with OPFRs, within a compact indoor microenvironment, to comply to fire safety regulations. Furthermore, petroleum products are a major source of PAHs in the environment and all the sampled cars in the study had combustion engines. Consequently, car dust is more likely to be polluted with PAHs stemming from petroleum combustion. Although previous investigations have noted an increase in heavy metals and brominated flame retardants with decreasing dust particles, this is the first study analyzing these SVOCs in different fractions of dust from various microenvironments. However, aside from two specific microenvironments, the observed pattern of escalating SVOC concentrations with smaller dust particle sizes was not corroborated among the examined microenvironments. This divergence in concentration trends suggests the potential involvement of supplementary variables in influencing SVOC distributions within dust particles.

Enantioselective biomarkers of maize toxicity induced by hexabromocyclododecane based on submicroscopic structure, gene expression and molecular docking.

Hexabromocyclododecane (HBCD), as a monitored chemical of the Chemical Weapons Convention, the Stockholm Convention and the Action Plan for New Pollutants Treatment in China, raises significant concerns on its impact of human health and food security. This study investigated enantiomer-specific biomarkers of HBCD in maize (Zea mays L.). Upon exposure to HBCD enantiomers, the maize root tip cell wall exhibited thinning, uneven cell gaps, and increased deposition on the cell outer wall. Elevated malondialdehyde (MDA) indicated lipid peroxidation, with higher mitochondrial membrane potential (MMP) inhibition in (+)-enantiomer treatments (47.2%-57.9%) than (-)-enantiomers (14.4%-37.4%). The cell death rate significantly increased by 37.7%-108.8% in roots and 16.4%-62.4% in shoots, accompanied by the upregulation of superoxide dismutase isoforms genes. Molecular docking presenting interactions between HBCD and target proteins, suggested that HBCD has an affinity for antioxidant enzyme receptors with higher binding energy for (+)-enantiomers, further confirming their stronger toxic effects. All indicators revealed that oxidative damage to maize seedlings was more severe after treatment with (+)-enantiomers compared to (-)-enantiomers. This study elucidates the biomarkers of phytotoxicity evolution induced by HBCD enantiomers, providing valuable insights for the formulation of more effective policies to safeguard environmental safety and human health in the future.

A Class Act? Regulating Organohalogen Flame Retardants in Groups versus Singly.

Regulating chemicals by class based on chemical similarities may help reduce risk of regrettable substitutions while enhancing health protection. A new Commentary summarizes OFR toxicity and exposure research to inform this effort.

Biomarkers of Organophosphate and Polybrominated Diphenyl Ether (PBDE) Flame Retardants of American Workers and Associations with Inhalation and Dermal Exposures.

This study evaluated workers' exposures to flame retardants, including polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs), and other brominated flame retardants (BFRs), in various industries. The study aimed to characterize OPE metabolite urinary concentrations and PBDE serum concentrations among workers from different industries, compare these concentrations between industries and the general population, and evaluate the likely route of exposure (dermal or inhalation). The results showed that workers from chemical manufacturing had significantly higher (p <0.05) urinary concentrations of OPE metabolites compared to other industries. Spray polyurethane foam workers had significantly higher (p <0.05) urinary concentrations of bis(1-chloro-2-propyl) phosphate (BCPP) compared to other industries. Electronic scrap workers had higher serum concentrations of certain PBDE congeners compared to the general population. Correlations were observed between hand wipe samples and air samples containing specific flame-retardant parent chemicals and urinary metabolite concentrations for some industries, suggesting both dermal absorption and inhalation as primary routes of exposure for OPEs. Overall, this study provides insights into occupational exposure to flame retardants in different industries and highlights the need for further research on emerging flame retardants and exposure reduction interventions.

Plastic breath: Quantification of microplastics and polymer additives in airborne particles.

The widespread extensive use of synthetic polymers has led to a substantial environmental crisis caused by plastic pollution, with microplastics detected in various environments and posing risks to both human health and ecosystems. The possibility of plastic fragments to be dispersed in the air as particles and inhaled by humans may cause damage to the respiratory and other body systems. Therefore, there is a particular need to study microplastics as air pollutants. In this study, we tested a combination of analytical pyrolysis, gas chromatography-mass spectrometry, and gas and liquid chromatography-mass spectrometry to identify and quantify both microplastics and their additives in airborne particulate matter and settled dust within a workplace environment: a WEEE treatment plant. Using this combined approach, we were able to accurately quantify ten synthetic polymers and eight classes of polymer additives. The identified additives include phthalates, adipates, citrates, sebacates, trimellitates, benzoates, organophosphates, and newly developed brominated flame retardants.

Decabromodifenyl Ether (BDE-209) in Surface Soils from Warsaw and Surrounding Areas: Characterization of Non-Carcinogenic Risk Associated with Oral and Dermal Exposure.

Polybrominated diphenyl ethers (PBDEs) have been used for many years as flame retardants. Due to their physicochemical and toxicological properties, they are considered to be persistent organic pollutants (POPs). BDE-209 is the main component of deca-BDE, the one PBDE commercial mixture currently approved for use in the European Union. The aim of this study was to analyse BDE-209 in surface soil samples from Warsaw and surrounding areas (Poland) as an indicator of environmental pollution with PBDEs, and to characterise the associated health risk. A total of 40 samples were analysed using gas chromatography with electron capture detection (GC-µECD). Concentrations of BDE-209 in soil ranged from 0.4 ng g-1 d.w. (limit of quantification) to 158 ng g-1 d.w. Overall, 52.5% of results were above the method's limit of quantification. The highest levels were found at several locations with heavy traffic and in the vicinity of a CHP plant in the city. The lowest concentrations were observed in most of the samples collected from low industrialized or green areas (<0.4 to 1.68 ng g-1 d.w.). Exposure to BDE-209 was estimated for one of the most sensitive populations, i.e., young children. The following exposure routes were selected: oral and dermal. No risk was found to young children's health.

A Comprehensive Review of Reactive Flame Retardants for Polyurethane Materials: Current Development and Future Opportunities in an Environmentally Friendly Direction.

Polyurethanes are among the most significant types of polymers in development; these materials are used to produce construction products intended for work in various conditions. Nowadays, it is important to develop methods for fire load reduction by using new kinds of additives or monomers containing elements responsible for materials' fire resistance. Currently, additive antipyrines or reactive flame retardants can be used during polyurethane material processing. The use of additives usually leads to the migration or volatilization of the additive to the surface of the material, which causes the loss of the resistance and aesthetic values of the product. Reactive flame retardants form compounds containing special functional groups that can be chemically bonded with monomers during polymerization, which can prevent volatilization or migration to the surface of the material. In this study, reactive flame retardants are compared. Their impacts on polyurethane flame retardancy, combustion mechanism, and environment are described.

Defective ferritinophagy and imbalanced iron metabolism in PBDE-47-triggered neuronal ferroptosis and salvage by Canolol.

The brominated flame retardant 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) is a ubiquitous environmental pollutant that causes neurotoxicity. However, incomplete understanding of the underlying mechanisms has hampered the development of effective intervention strategies. Oxidative stress and related cell death are the modes of action for PBDE-47 neurotoxicity, which are also the characteristics of ferroptosis. Nonetheless, the role of ferroptosis in PBDE-47-induced neurotoxicity remains unclear. In the present study, we found that PBDE-47 triggered ferroptosis in neuron-like PC12 cells, as evidenced by intracellular iron overload, lipid peroxidation, and mitochondrial damage. This was confirmed by ferroptosis inhibitors including the lipid reactive oxygen species scavenger ferrostatin-1 and iron chelator deferoxamine mesylate. Mechanistically, PBDE-47 impaired ferritinophagy by disrupting nuclear receptor coactivator 4-mediated lysosomal degradation of the iron storage protein ferritin. Moreover, PBDE-47 disturbed iron metabolism by increasing cellular iron import via upregulation of transferrin receptor 1 and decreasing cellular iron export via downregulation of ferroportin 1 (FPN1). Intriguingly, rescuing lysosomal function by overexpressing cathepsin B (CatB) mitigated PBDE-47-induced ferroptosis by partially restoring dysfunctional ferritinophagy and enhancing iron excretion via the upregulation of FPN1. However, FPN1 knockdown reversed the beneficial effects of CatB overexpression on the PBDE-47-induced iron overload. Finally, network pharmacology integrated with experimental validation revealed that Canolol, the main phenolic compound in canola oil, protected against PBDE-47-evoked iron overload, resulting in ferroptosis by restoring defective ferritinophagy and improving abnormal iron metabolism via lowering iron uptake and facilitating iron excretion. Overall, these data suggest that ferroptosis is a novel mechanism of PBDE-47-induced neuronal death and that manipulation of ferritinophagy and iron metabolism via Canolol represents a promising therapeutic strategy.

The role of iron materials in the abiotic transformation and biotransformation of polybrominated diphenyl ethers (PBDEs): A review.

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants, easily enter the environment, thus posing environmental and health risks. Iron materials play a key role during the migration and transformation of PBDEs. This article reviews the processes and mechanisms of adsorption, degradation, and biological uptake and transformation of PBDEs affected by iron materials in the environment. Iron materials can effectively adsorb PBDEs through hydrophobic interactions, π-π interactions, hydrogen/halogen bonds, electrostatic interactions, coordination interactions, and pore filling interactions. In addition, they are beneficial for the photodegradation, reduction debromination, and advanced oxidation degradation and debromination of PBDEs. The iron material-microorganism coupling technology affects the uptake and transformation of PBDEs. In addition, iron materials can reduce the uptake of PBDEs in plants, affecting their bioavailability. The species, concentration, and size of iron materials affect plant physiology. Overall, iron materials play a bidirectional role in the biological uptake and transformation of PBDEs. It is necessary to strengthen the positive role of iron materials in reducing the environmental and health risks caused by PBDEs. This article provides innovative ideas for the rational use of iron materials in controlling the migration and transformation of PBDEs in the environment.

Flame Retardant Exposure in Vehicles Is Influenced by Use in Seat Foam and Temperature.

Flame retardants (FRs) are added to vehicles to meet flammability standards, such as US Federal Motor Vehicle Safety Standard FMVSS 302. However, an understanding of which FRs are being used, sources in the vehicle, and implications for human exposure is lacking. US participants (n = 101) owning a vehicle of model year 2015 or newer hung a silicone passive sampler on their rearview mirror for 7 days. Fifty-one of 101 participants collected a foam sample from a vehicle seat. Organophosphate esters (OPEs) were the most frequently detected FR class in the passive samplers. Among these, tris(1-chloro-isopropyl) phosphate (TCIPP) had a 99% detection frequency and was measured at levels ranging from 0.2 to 11,600 ng/g of sampler. TCIPP was also the dominant FR detected in the vehicle seat foam. Sampler FR concentrations were significantly correlated with average ambient temperature and were 2-5 times higher in the summer compared to winter. The presence of TCIPP in foam resulted in ∼4 times higher median air sampler concentrations in winter and ∼9 times higher in summer. These results suggest that FRs used in vehicle interiors, such as in seat foam, are a source of OPE exposure, which is increased in warmer temperatures.

Associations between organophosphate esters and bone mineral density in adults in the United States: 2011-2018 NHANES.

BACKGROUND: Organophosphate esters (OPEs) are used extensively as flame retardants and plasticizers. Laboratory studies have shown that OPEs exhibit osteotoxicity by inhibiting osteoblast differentiation; however, little is known about how OPEs exposure is associated with bone health in humans. OBJECTIVES: We conducted a cross-sectional study to investigate the association between OPEs exposure and bone mineral density (BMD) in adults in the United States using data from the 2011-2018 National Health and Nutrition Examination Survey (NHANES). METHODS: Multivariate linear regression models were used to assess the association between concentrations of individual OPE metabolites and BMDs. We also used the Bayesian kernel machine regression (BKMR) and quantile g-computation (qgcomp) models to estimate joint associations between OPE mixture exposure and BMDs. All the analyses were stratified according to gender. RESULTS: A total of 3546 participants (median age, 40 years [IQR, 30-50 years]; 50.11% male) were included in this study. Five urinary OPE metabolites with a detection rate of > 50% were analyzed. After adjusting for the potential confounders, OPE metabolite concentrations were associated with decreased total-body BMD and lumbar spine BMD in males, although some associations only reached significance for bis(1-chloro-2-propyl) phosphate (BCPP), dibutyl phosphate (DBUP), and bis(2-chloroethyl) phosphate (BCEP) (ß = -0.013, 95% CI: -0.026, -0.001 for BCPP and total-body BMD; ß = -0.022, 95% CI: -0.043, -0.0001 for DBUP and lumbar spine BMD; ß=-0.018, 95% CI: -0.034, -0.002 for BCEP and lumbar spine BMD). OPE mixture exposure was also inversely associated with BMD in males, as demonstrated in the BMKR and qgcomp models. CONCLUSIONS: This study provides preliminary evidence that urinary OPE metabolite concentrations are inversely associated with BMD. The results also suggested that males were more vulnerable than females. However, further studies are required to confirm these findings.

Interactions of Brominated Flame Retardants with Membrane Models of Dehalogenating Bacteria: Langmuir Monolayer and Grazing Incidence X-ray Diffraction Studies.

Brominated flame retardants (BFRs) are small organic molecules containing several bromine substituents added to plastics to limit their flammability. BFRs can constitute up to 30% of the weight of some plastics, which is why they are produced in large quantities. Along with plastic waste and microplastic particles, BFRs end up in the soil and can easily leach causing contamination. As polyhalogenated molecules, multiple BFRs were classified as persistent organic pollutants (POPs), meaning that their biodegradation in the soils is especially challenging. However, some anaerobic bacteria as Dehaloccocoides can dehalogenate BFRs, which is important in the bioremediation of contaminated soils. BFRs are hydrophobic, can accumulate in plasma membranes, and disturb their function. On the other hand, limited membrane accumulation is necessary for BFR dehalogenation. To study the BFR-membrane interaction, we created membrane models of soil dehalogenating bacteria and tested their interactions with seven legacy and novel BFRs most common in soils. Phospholipid Langmuir monolayers with appropriate composition were used as membrane models. These membranes were doped in the selected BFRs, and the incorporation of BFR molecules into the phospholipid matrix and also the effects of BFR presence on membrane physical properties and morphology were studied. It turned out that the seven BFRs differed significantly in their membrane affinity. For some, the incorporation was very limited, and others incorporated effectively and could affect membrane properties, while one of the tested molecules induced the formation of bilayer domains in the membranes. Thus, Langmuir monolayers can be effectively used for pretesting BFR membrane activity.

Five coexisting brominated flame retardants in a water-sediment-Vallisneria system: Bioaccumulation and effects on oxidative stress and photosynthesis.

The pollution of various brominated flame retardants (BFRs) is concurrence, while their environmental fate and toxicology in water-sediment-submerged plant systems remain unclear. In this study, Vallisneria natans plants were co-exposed to 2,3,4,5,6-pentabromotoluene (PBT), hexabromobenzene (HBB), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ether (BDE209), and decabromodiphenyl ethane (DBDPE). The ∑BFRs concentration in the root was 2.15 times higher than that in the shoot. Vallisneria natans accumulated more BTBPE and HBB in 0.2, 1, and 5 mg/kg treatments, while they accumulated more DBDPE and BDE209 in 25 and 50 mg/kg treatments. The bioaccumulation factors in the shoot and root were 1.08-96.95 and 0.04-0.70, respectively. BFRs in sediments had a more pronounced effect on bioaccumulation levels than BFRs in water, and biotranslocation was another potential influence factor. The SOD activity, POD activity, and MDA content were significantly increased under co-exposure. The DBDPE separate exposure impacted the metabolism of substances and energy, inhibited mismatch repair, and disrupted ribosomal functions in Vallisneria natans. However, DBDPE enhanced their photosynthesis by upregulating the expression level of genes related to the light reaction. This study provides a broader understanding of the bioaccumulation and toxicity of BFRs in submerged plants, shedding light on the scientific management of products containing BFRs.

Synergistic effect of phytic acid and eggshell bio-fillers on the dual-phase fire-retardancy of intumescent coatings applied on cellulosic substrates.

Cellulosic substrates, including wood and thatch, have become icons for sustainable architecture and construction, however, they suffer from high flammability because of their inherent cellulosic composition. Current control measures for such hazards include applying intumescent fire-retardant (IFR) coatings that swell and form a char layer upon ignition, protecting the underlying substrate from burning. Typically, conventional IFR coatings are opaque and are made of halogenated compounds that release toxic fumes when ignited, compromising the roofing's aesthetic value and sustainability. In this work, phytic acid, a naturally occurring phosphorus source extracted from rice bran, was used to synthesize phytic acid-based fire-retardants (PFR) via esterification under reflux, along with powdered chicken eggshells (CES) as calcium carbonate (CaCO3) bio-filler. These components were incorporated into melamine formaldehyde resin to produce the transparent IFR coating. It was revealed that the developed IFR coatings achieved the highest fire protection rating based on UL94 flammability standards compared to the control. The coatings also yielded increased LOI values, indicative of self-extinguishing properties. A 17 °C elevation of the IFR coating's melting temperature and a significant ∼172% increase in enthalpy change from the control were observed, indicating enhanced fire-retardancy. The thermal stability of the coatings was improved, denoted by reduced mass losses, and increased residual masses after thermal degradation. As validated by microscopy and spectroscopy, the abundance of phosphorus and carbon groups in the coatings' condensed phase after combustion indicates enhanced char formation. In the gas phase, TG-FTIR showed the evolution of non-flammable CO2, and fire-retardant PO and P-O-C. Mechanical property testing confirmed no reduction in the adhesion strength of the IFR coating. With these results, the developed IFR coating exhibited enhanced fire-retardancy whilst remaining optically transparent, suggestive of a dual-phase IFR protective mechanism involving the release of gaseous combustion diluents and the formation of a thermally insulating char layer.