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Frontiers in Microbiology 2021Advanced physicochemical and chemical absorption methods for chlorinated ethenes are feasible but incur high costs and leave traces of pollutants on the site....
Advanced physicochemical and chemical absorption methods for chlorinated ethenes are feasible but incur high costs and leave traces of pollutants on the site. Biodegradation of such pollutants by anaerobic or aerobic bacteria is emerging as a potential alternative. Several mycobacteria including L1, NBB4, JS60, NBB3 and JS623 have previously been described as assimilators of vinyl chloride (VC). In this study, we compared nucleotide sequence of VC cluster and performed a taxogenomic evaluation of these mycobacterial species. The results showed that the complete VC cluster was acquired by horizontal gene transfer and not intrinsic to the genus . These results also revealed the presence of an additional F1 gene that seems to be involved in Coenzyme M biosynthesis, which is ultimately used in the VC degradation pathway. Furthermore, we suggest for the first time that S/N-Oxide reductase encoding gene was involved in the dissociation of the SsuABC transporters from the organosulfur, which play a crucial role in the Coenzyme M biosynthesis. Based on genomic data, L1, NBB4 JS60, NBB3 and JS623 were misclassified and form a novel species within the genus . L1 (CECT 8761 = DSM 6695) was the subject of polyphasic taxonomic studies and showed ANI and dDDH values of 84.7 and 28.5% with its close phylogenetic neighbour, ATCC 33027. Phenotypic, chemotaxonomic and genomic data considering strain L1 (CECT 8761 = DSM 6695) as a type strain of novel species with the proposed name, sp. nov.
PubMed: 35003006
DOI: 10.3389/fmicb.2021.767895 -
International Journal of Environmental... Feb 2022Public complaints have raised concerns that some mattresses in the current marketplace may be potential sources of airborne fiberglass. Although mattress foam is often...
Public complaints have raised concerns that some mattresses in the current marketplace may be potential sources of airborne fiberglass. Although mattress foam is often marketed as chemical-free, their cover compositions are not as well understood by the general public. To fill these basic information gaps, the covers of four newly purchased mattresses were sampled and analyzed using polarized light microscopy, SEM-EDS, and FTIR microspectroscopy. Two of the mattress covers contained over 50% fiberglass in their inner sock layers. Up to 1% of the fiberglass had migrated to adjacent fabric layers, representing a potential risk of consumer exposure if the zipper on the outer cover is opened. The observed fiberglass fragments had calculated aerodynamic diameters ranging between 30 and 50 µm, suggesting they are potentially inhalable into the nose, mouth, and throat, but are likely too large to penetrate deeper into the lungs. No fiberglass was observed on the brand new mattresses' outer surfaces. Synthetic fibers also present in the sock layers were consistent with flame resistant modacrylic containing vinyl chloride and antimony. The use of fiberglass and other chemicals in mattress covers poses a potential health risk if these materials are not adequately contained. The apparent non-inclusion of mattress covers in chemical-free certifications suggests that further improvements are needed in mattress labeling and education of consumers.
Topics: Antimony; Beds; Glass
PubMed: 35162717
DOI: 10.3390/ijerph19031695 -
Waste Management (New York, N.Y.) Feb 2021Calcium metal soap and polyol (dipentaerythritol) additives are replacing or partially replacing organotin in poly(vinyl chloride) (PVC) heat stabilizers due to their...
Calcium metal soap and polyol (dipentaerythritol) additives are replacing or partially replacing organotin in poly(vinyl chloride) (PVC) heat stabilizers due to their low cost, nontoxicity and safety. Therefore, investigating the low-temperature thermal oxidative degradation of stabilized plasticized PVC from the source is essential for recycling. This work uses isothermal thermogravimetry to investigate the thermal degradation process and isothermal discoloration of PVC/calcium metal soap/dipentaerythritol/organotin soft products with excellent heat resistance at 453-503 K and under air atmosphere. The chemical kinetics method is used to fit a single equation model of mass loss and time during the thermal oxidation degradation of PVC, and the kinetic equation obtained is: -ln(1 - α) = 3.83 × 10exp (-6834.4/T)t. When the temperature is 453-503 K, the calculation results are basically consistent with the experimental data and are independent of the heating rate and temperature changes. In addition, the isothermal discoloration of different PVC materials was tested under air atmosphere at 468 K. The results show that when the test material is PVC/calcium metal soap/dipentaerythritol/organotin, the heat aging time to become completely blackened is longer than that of the blank sample, which indicates a strong interaction occurs between Sn, Ca and dipentaerythritol complexes and PVC molecules, inhibiting the release of hydrogen chloride. At the same time, in order to recover PVC and prevent it from carbonization, if the temperature is set to 486 K, the thermal oxidation degradation time of PVC should be less than 130 min.
Topics: Kinetics; Oxidative Stress; Polyvinyl Chloride; Temperature; Vinyl Chloride
PubMed: 33348230
DOI: 10.1016/j.wasman.2020.11.019 -
International Journal of Systematic and... May 2023A strictly anaerobic, organohalide-respiring bacterium, designated strain GP, was characterized using a polyphasic approach. GP is Gram-stain-negative, non-spore-forming...
A strictly anaerobic, organohalide-respiring bacterium, designated strain GP, was characterized using a polyphasic approach. GP is Gram-stain-negative, non-spore-forming and non-motile. Cells are irregular cocci ranging between 0.6 and 0.9 µm in diameter. GP couples growth with the reductive dechlorination of 1,2-dichloroethane, vinyl chloride and all polychlorinated ethenes, except tetrachloroethene, yielding ethene and inorganic chloride as dechlorination end products. H and formate serve as electron donors for organohalide respiration in the presence of acetate as carbon source. Major cellular fatty acids include C, Cω9, C, C and C. On the basis of 16S rRNA gene phylogeny, GP is most closely related to NSZ-14 and IP3-3 with 99.8 and 97.4 % sequence identities, respectively. Genome-wide pairwise comparisons based on average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization do not support the inclusion of GP in previously described species of the genus with validly published names. On the basis of phylogenetic, physiological and phenotypic traits, GP represents a novel species within the genus , for which the name sp. nov. is proposed. The type strain is GP (= JCM 39172 = CGMCC 1.17861).
Topics: Fatty Acids; Vitis; Phylogeny; RNA, Ribosomal, 16S; Base Composition; DNA, Bacterial; Bacterial Typing Techniques; Sequence Analysis, DNA; Bacteria, Anaerobic; Oxidation-Reduction; Formates; Phospholipids
PubMed: 37185088
DOI: 10.1099/ijsem.0.005881 -
Environmental Science & Technology Apr 2023Nanoplastics (NPs) have raised global concern owing to their potential health effects. Herein, after simulated and natural solar irradiation, polyethylene,...
Nanoplastics (NPs) have raised global concern owing to their potential health effects. Herein, after simulated and natural solar irradiation, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride) nanoplastics (PVC NPs) were observed to exhibit enhanced fluorescence, particularly PVC NPs. Furthermore, the role of photoaged NPs as a potential fluorescence indicator was evaluated by exposing a model aquatic organism to these NPs. Our results revealed that photoaged NPs exhibited strong fluorescence owing to the generation of conjugated π bonds, which can achieve π-π* electron transition with low energy consumption. Photogenerated fluorescence also enabled the photoaged NPs to act as efficient fluorescent tracers, which can help track NP migration in various organisms. The results of two-photon laser confocal scanning microscopy revealed that the photoaged NPs could translocate across biological barriers and accumulate in extraintestinal tissues in addition to being ingested and excreted. Moreover, compared with pristine NPs, the photoaged NPs underwent biodegradation more easily, probably because of increased hydrophilicity due to photogenerated oxygen-containing moieties. Therefore, in addition to producing fluorescent NPs without the attachment of external fluorescent dyes, the natural photoaging process can promote the migration and degradation of photoaged NPs in food chains.
Topics: Microplastics; Polystyrenes; Aquatic Organisms; Solar Energy; Polyethylene; Coloring Agents; Water Pollutants, Chemical; Nanoparticles
PubMed: 37042100
DOI: 10.1021/acs.est.2c07537 -
Polymers Mar 2021This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing...
This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing of poly(vinyl chloride). It was observed that the pomace in this study was used to extract naphtha, thereby permitting the removal of bio-oil as a factor preventing the obtaining of homogeneous composites. Furthermore, adding 20% raspberry pomace filler after extraction extended the thermal stability time for the composites by about 30%. It was observed that composite density, impact strength, and tensile strength values decreased significantly with increasing concentrations of filler in the PVC matrix. At the same time, their modulus of elasticity and Shore hardness increased. All tested composites were characterized by a good burning resistance with a flammability rating of V0 according to the UL94 test. Adding 20 to 40% of a natural filler to the PVC matrix made it possible to obtain composites for the production of flame resistant elements that emitted less hydrogen chloride under fire conditions while ensuring good rigidity.
PubMed: 33805463
DOI: 10.3390/polym13071079 -
Toxicology and Applied Pharmacology Oct 2019Vinyl chloride (VC) is a common industrial organochlorine, shown to cause hepatic angiosarcoma and hepatic steatosis. However, the role of endoplasmic reticulum stress...
Vinyl chloride (VC) is a common industrial organochlorine, shown to cause hepatic angiosarcoma and hepatic steatosis. However, the role of endoplasmic reticulum stress (ERS) and oxidative stress (OS) in hepatic steatosis after subchronic exposure to VC in mice, is unclear. Based on body weight, forty healthy SPF male C57BL/6 J mice were randomly divided into a control group and three VC exposure groups (57.3, 286.7, and 1433.6 ppm) (n = 10 each). VC was administered by static inhalation in a 50 L sealed plexiglass inhalation chamber for 2 h per day, five days per week for 16 weeks. Serum and liver tissues were analyzed for liver enzymes and lipids. Hepatic cytochrome P450 2E1 (CYP2E1) and OS related indicators malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were measured. The mRNA expressions of ERS downstream genes, including glycoregulatory protein-78 (GRP-78), sterol regulatory element binding protein-1 (SREBP-1), Acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS) were detected by real-time PCR (RT-PCR) and their protein levels examined by western blotting. The CYP2E1 levels increased after VC administration in a dose-dependent manner. MDA levels increased (P < .05) and SOD and GSH levels decreased (P < .05) in the liver of each group with the increase in the dose of VC. ERS and expressions of downstream genes (GRP-78, SREBP-1, ACC, and FAS) were enhanced after VC administration. These results suggested that OS and ERS could be induced by VC, which may lead to an increase in fatty acid synthesis in the liver, further aggravating hepatic steatosis.
Topics: Acetyl-CoA Carboxylase; Administration, Inhalation; Animals; Cytochrome P-450 CYP2E1; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Fatty Liver; Heat-Shock Proteins; Liver; Male; Mice, Inbred C57BL; Oxidative Stress; Sterol Regulatory Element Binding Protein 1; Vinyl Chloride; fas Receptor
PubMed: 31445928
DOI: 10.1016/j.taap.2019.114730 -
Environmental Pollution (Barking, Essex... Nov 2023Sulfidated zero-valent iron (ZVI) and biochar-supported ZVI have received increasing attention for their potential to dechlorinate trichloroethylene. However, minimal...
Enhanced removal of cis-1,2-dichloroethene and vinyl chloride in groundwater using ball-milled sulfur- and biochar-modified zero-valent iron: From the laboratory to the field.
Sulfidated zero-valent iron (ZVI) and biochar-supported ZVI have received increasing attention for their potential to dechlorinate trichloroethylene. However, minimal data are available regarding the combined effect of sulfur and biochar ZVI on trichloroethylene byproducts. The primary aim of the current study is to determine whether sulfur- and biochar-modified ZVI (ZVI-BC-S) enhances the removal of cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC) from groundwater. Results show that biochar and sulfur facilitated the milling of ZVI-BC-S into micro- and nanoscale particles and increased FeS formation. Moreover, the rates of cDCE and VC removal by ZVI-S increased by 30.1% and 30.2%, respectively, compared to those obtained with ZVI, owing to enhanced dechlorination via β-elimination by sulfur. Meanwhile, treatment with ZVI-BC-S harnessed the benefits of biochar and sulfur to enhance the cDCE and VC removal rates by 62.0% and 67.7%, respectively. Mechanistically, biochar enhanced the corrosion of ZVI-S to increase FeS production and enhance the electron transfer, β-elimination, and hydrogenolysis involved in cDCE and VC dechlorination. The effectiveness of ZVI-BC-S was confirmed in a field demonstration, during which cDCE and VC concentrations significantly decreased within 10 days following injection. The findings of this study can help inform the rational design of ZVI for in-situ remediation of chlorinated hydrocarbons in groundwater.
PubMed: 37604391
DOI: 10.1016/j.envpol.2023.122424 -
Journal of the Air & Waste Management... Oct 2019This study reports on the occupational inhalation exposure to VOCs of workers in the Kuwaiti printing industry. Using the evacuated canister methodology, we targeted 72...
This study reports on the occupational inhalation exposure to VOCs of workers in the Kuwaiti printing industry. Using the evacuated canister methodology, we targeted 72 VOCs in three printeries and compared the concentrations to previous reports and relevant occupational exposure levels (OELs). We found that recent efforts in the printing industry to reduce VOC usage had been successful, as concentrations of key hazardous VOCs were substantially lower than anticipated. On the other hand, nearly all target VOCs were found. Non-production areas were sampled along with the offset printing areas, another strength of this study, and revealed exposures to hazardous VOCs among administers and digital printer and CTP operators. Exposure to ototoxic VOCs amounted to 1-3% of the OEL, consisting mostly of ethylbenzene, which was likely in use in two of the study printeries. Exposure to carcinogenic or probably carcinogenic VOCs was 15-20% of the OEL at four locations across the three printeries, consisting mostly of vinyl chloride and benzyl chloride. Vinyl chloride VOC was partially sourced from outdoors, but was also likely used inside the study printeries. Interestingly, concentrations of vinyl chloride were similar in most sampling locations to that of CFC-114, a CFC banned by the Montreal Protocol and not commonly used as a refrigerant. This unexpected finding suggests further study is warranted to identify the use of these VOCs in printeries. Exposure to hazardous VOCs up to nearly 50% of the OEL, consisting largely of bromoform and vinyl chloride. Bromoform was found in all the study printeries, sourced partially from outdoor air. The higher concentrations found inside the study printeries likely resulted from the use of the desalinated water for washing. This finding raises of emissions from sources other than blanket washes, and inks, etc. adding to the total VOC load in printery indoor air. : Results from this study indicate that efforts to reduce worker exposure to VOCs particularly dangerous to human health in recent years have been successful, but there is still much to be done to protect workers. Exposures to ototoxic and carcinogenic VOCs were identified, among both production and non-production workers. Unexpected findings included the apparent use in printing activities of the carcinogen vinyl chloride and CFC-114, banned under the Montreal Protocol. Observed lapses in safety procedures included failure to utilize ventilation systems and closing doors between work areas, indicating management and worker education should remain a priority.
Topics: Air Pollutants, Occupational; Benzene Derivatives; Benzyl Compounds; Environmental Monitoring; Humans; Industry; Inhalation Exposure; Occupational Exposure; Printing; Trihalomethanes; Vinyl Chloride; Volatile Organic Compounds
PubMed: 31184550
DOI: 10.1080/10962247.2019.1629355 -
Organic Letters Dec 2022()- and ()-isocyanoalkenes were selectively synthesized via the sequential cross coupling of vinyl iodides with formamide, followed by dehydration. The optimal catalyst,...
()- and ()-isocyanoalkenes were selectively synthesized via the sequential cross coupling of vinyl iodides with formamide, followed by dehydration. The optimal catalyst, generated in situ from CuI and -dimethyl-1,2-cyclohexanediamine, rapidly coupled ()- or ()-vinyl iodides with formamide, which minimized the isomerization of the resultant vinyl formamide. The method efficiently provided a range of acyclic, carbocyclic, and heterocyclic isocyanoalkenes; the versatility is illustrated with the selective, stereodivergent syntheses of the diastereomeric isocyanoalkene antibiotics, B371 and -B371.
Topics: Anti-Bacterial Agents; Formamides; Iodides; Polyvinyl Chloride
PubMed: 36399331
DOI: 10.1021/acs.orglett.2c03461