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The East Palestine, Ohio train derailment released toxic vinyl chloride (VC) and butyl acrylate (BA), which entered the watershed. Streambed sediment, surface water, and private well water samples were collected 128 and 276 days postaccident to assess the natural attenuation potential of VC and BA by quantifying biodegradation biomarker genes and conducting microcosm treatability studies. qPCR detected the aerobic VC degradation biomarkers etnC in ∼40% and etnE in ∼27% of sediments collected in both sampling campaigns in abundances reaching 10 5 gene copies g -1 . The 16S rRNA genes of organohalide-respiring Dehalococcoides and Dehalogenimonas were, respectively, detected in 50 and 64% of sediment samples collected 128 days postaccident and in 63 and 88% of sediment samples collected 276 days postaccident, in abundances reaching 10 7 cells g -1 . Elevated detection frequencies of VC degradation biomarker genes were measured immediately downstream of the accident site (i.e., Sulphur Run). Aerobic VC degradation occurred in all sediment microcosms and coincided with increases of etnC / etnE genes and Mycobacterium , a genus comprising aerobic VC degraders. The conversion of VC to ethene and an increased abundance of VC reductive dechlorination biomarker genes were observed in microcosms established with sediments collected from Sulphur Run. All anoxic microcosms rapidly degraded BA to innocuous products with intermediate formation of n -butanol and acrylate. The results indicate that microbiomes in the East Palestine watershed have natural attenuation capacity for VC and BA. Recommendations are made to improve first-response actions in future contaminant release accidents of this magnitude.

Background: Chemicals emitted from industrial facilities include known or suspected mammary carcinogens and endocrine disruptors, but epidemiologic studies are limited. We evaluated associations between air emissions of multiple carcinogenic chemicals and postmenopausal breast cancer risk in a large prospective U.S., Methods: We used the U.S. Environmental Protection Agency's Toxics Release Inventory to estimate historical airborne emissions (1987-1995) of 19 known and probable carcinogens for participants enrolled (1995-1996) in the NIH-AARP Diet and Health Study. Among 170,402 women, 15,124 breast cancers were diagnosed through 2018. We constructed inverse distance- and wind-weighted average emissions metrics within 1, 2, 5, and 10 km of the enrollment address for each chemical. We estimated multivariable adjusted HRs and 95 % CIs for categories (quartiles, tertiles, medians) of each chemical in association with breast cancer overall and separately by type (invasive, ductal carcinoma in situ) and estrogen receptor (ER) status., Results: We observed an association between benzene emissions and breast cancer risk that was strongest at 1 km (HR Q4 vs. non-exposed = 2.06, 95 %CI: 1.34-3.17; p-trend = 0.001). The magnitude of the association weakened with increasing distance (2 km HR Q4 vs. non-exposed = 1.17, 95 %CI=0.92-1.49; p-trend = 0.19; 5 km HR Q4 vs. non-exposed = 1.05, 95 %CI=0.94-1.16; p-trend = 0.37; 10 km HR Q4 vs. non-exposed = 0.95, 95 %CI=0.89-1.02; p-trend = 0.19) and appeared to be most relevant for invasive rather than intraductal disease. Overall risk was also elevated for vinyl chloride at 5 km (HR ≥median vs. non-exposed = 1.20, 95 %CI=1.01-1.43; p-trend = 0.04), but not 2 km or 10 km. We observed suggestive associations for asbestos, trichloroethylene, and styrene in different subgroup analyses, but risk patterns were not clear across distances. Associations with other chemicals were generally null, with limited evidence of heterogeneity by disease type or ER status., Conclusions: An increased risk of breast cancer associated with relatively high levels of industrial benzene emissions warrants additional study, particularly among participants with diverse sociodemographic characteristics that live in areas with higher density of industrial facilities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Occupational dermatitis (OD) is an inflammatory skin disease stemming from exposure to specific substances within a work setting. As the second most prevalent occupational health concern in 2020, affecting 1.8 per 10,000 workers, OD poses a significant challenge to workforce well-being and imposes a substantial economic burden through lost wages, decreased productivity, and increased healthcare spending. Dermatologists emerge as pivotal figures in recognizing risk factors and delivering essential care to individuals with OD. This review focuses on chemical hazards and toxic substances regulated by the Occupational Safety and Health Administration across general industry, maritime, and construction sectors. It explores the background of each hazard, pathophysiology to dermatitis, and human cases reported between 2017 and 2023 for formaldehyde, chromium, vinyl chloride, and cadmium., (© 2024 The Author(s). International Journal of Dermatology published by Wiley Periodicals LLC on behalf of the International Society of Dermatology.)

Polymers are omnipresent in our daily life thanks to their low production cost and their ease of implementation, which makes thermoplastics more usable in supplying drinking water, distributing cold and hot water, and transporting hot corrosive fluids and industrial chemicals, including inorganic acids. The material of our study is chlorinated polyvinyl chloride (CPVC); it has better thermal insulation and a wide operating temperature range. This paper deals with the impact of thermal aging over time on the behavior of CPVC by performing two types of tests according to ISO 15877 (EN ISO 15877) two types of tests; the first is thermal aging (Fig. 1) at a temperature of 95 °C and a pressure of 10 bars for periods of up to 2000 h and the second test exposure of the pipeline to pressure until bursting. On the basis of the test results, we can predict the rupture of the pipeline and thus avoid the dangerous accidents due to the bursting under the effect of the pressure and the high temperature; by using the results of this study, the inspectors change CPVC structures at the right time, neither too early when the part is still in good condition nor too late after failure; this will be very useful to save water and money and of course save the environment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Hollongdione is the first recorded example of the occurrence of a dammarane hexanor-triterpene in nature possessing antiviral and cytotoxic activity. Its simple one-stage transformation into compounds with terminal alkyne and vinyl chloride fragments via the interaction with phosphorus halides is reported. The copper(I)-catalyzed Mannich reaction of 3-oxo-22,23,24,25,26,27-hexanor-dammar-20(21)-in 3 led to a series of aminomethylated products, while 17-carboxylic acid was obtained by ozone oxidation of 3-oxo-22,23,24,25,26,27-hexanor-dammar-20-chloro-20(21)-en 4 ; the following direct amidation of the latter has been developed. The structures of all new molecules were established by spectroscopic studies that included 2D NMR correlation methods; the molecular structures of compounds 2 - 5 were determined by X-ray analysis.

Background: Drinking water at U.S. Marine Corps Base (MCB) Camp Lejeune, North Carolina was contaminated with trichloroethylene and other industrial solvents from 1953 to 1985., Methods: A cohort mortality study was conducted of Marines/Navy personnel who, between 1975 and 1985, began service and were stationed at Camp Lejeune (N = 159,128) or MCB Camp Pendleton, California (N = 168,406), and civilian workers employed at Camp Lejeune (N = 7,332) or Camp Pendleton (N = 6,677) between October 1972 and December 1985. Camp Pendleton's drinking water was not contaminated with industrial solvents. Mortality follow-up was between 1979 and 2018. Proportional hazards regression was used to calculate adjusted hazard ratios (aHRs) comparing mortality rates between Camp Lejeune and Camp Pendleton cohorts. The ratio of upper and lower 95% confidence interval (CI) limits, or CIR, was used to evaluate the precision of aHRs. The study focused on underlying causes of death with aHRs ≥ 1.20 and CIRs ≤ 3., Results: Deaths among Camp Lejeune and Camp Pendleton Marines/Navy personnel totaled 19,250 and 21,134, respectively. Deaths among Camp Lejeune and Camp Pendleton civilian workers totaled 3,055 and 3,280, respectively. Compared to Camp Pendleton Marines/Navy personnel, Camp Lejeune had aHRs ≥ 1.20 with CIRs ≤ 3 for cancers of the kidney (aHR = 1.21, 95% CI: 0.95, 1.54), esophagus (aHR = 1.24, 95% CI: 1.00, 1.54) and female breast (aHR = 1.20, 95% CI: 0.73, 1.98). Causes of death with aHRs ≥ 1.20 and CIR > 3, included Parkinson disease, myelodysplastic syndrome and cancers of the testes, cervix and ovary. Compared to Camp Pendleton civilian workers, Camp Lejeune had aHRs ≥ 1.20 with CIRs ≤ 3 for chronic kidney disease (aHR = 1.88, 95% CI: 1.13, 3.11) and Parkinson disease (aHR = 1.21, 95% CI: 0.72, 2.04). Female breast cancer had an aHR of 1.19 (95% CI: 0.76, 1.88), and aHRs ≥ 1.20 with CIRs > 3 were observed for kidney and pharyngeal cancers, melanoma, Hodgkin lymphoma, and chronic myeloid leukemia. Quantitative bias analyses indicated that confounding due to smoking and alcohol consumption would not appreciably impact the findings., Conclusion: Marines/Navy personnel and civilian workers likely exposed to contaminated drinking water at Camp Lejeune had increased hazard ratios for several causes of death compared to Camp Pendleton., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background: A growing literature has reported associations between traffic-related air pollution and breast cancer, however there are fewer investigations into specific ambient agents and any putative risk of breast cancer development, particularly studies occurring in populations residing in higher pollution areas such as Los Angeles., Objectives: To estimate breast cancer risks related to ambient air toxics exposure at residential addresses., Methods: We examined the relationships between ambient air toxics and breast cancer risk in the Multiethnic Cohort among 48,665 California female participants followed for cancer from 2003 through 2013. We obtained exposure data on chemicals acting as endocrine disruptors or mammary gland carcinogens from the National-Scale Air Toxics Assessment. Cox proportional hazards models were used to estimate breast cancer risk per one interquartile range (IQR) increase in air toxics exposure lagged by 5-years. Stratified analyses were conducted by race, ethnicity, and hormone receptor types., Results: Among all women, increased risks of invasive breast cancer were observed with toxicants related to industries [1,1,2,2-tetrachloroethane (hazard ratio [HR] = 4.22, 95% confidence interval [95% CI] 3.18-5.60), ethylene dichloride (HR = 2.81, 95% CI 2.20-3.59), and vinyl chloride (HR = 2.27, 95% CI 1.81, 2.85); these 3 agents were correlated (r2 = 0.45-0.77)]. Agents related to gasoline production or combustion were related to increased breast cancer risk [benzene (HR = 1.32, 95% CI 1.24, 1.41), ethylbenzene (HR = 1.20, 95% CI 1.13-1.28), toluene (HR = 1.29, 95% CI 1.20-1.38), naphthalene (HR = 1.11, 95% CI 1.02-2.22), acrolein (HR = 2.26, 95% CI 1.92, 2.65)]. Higher hazard ratios were observed in African Americans and Whites compared to other racial and ethnic groups (p-heterogeneity <0.05 for traffic-related air toxics, acrolein, and vinyl acetate)., Conclusions: Our findings suggest that specific toxic air pollutants may be associated with increase breast cancer risk., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

The endotracheal tube (ETT) affords support for intubated patients, but the increasing incidence of ventilator-associated pneumonia (VAP) is jeopardizing its application. ETT surfaces promote (poly)microbial colonization and biofilm formation, with a heavy burden for VAP. Devising safe, broad-spectrum antimicrobial materials to tackle the ETT bioburden is needful. Herein, we immobilized ciprofloxacin (CIP) and/or chlorhexidine (CHX), through polydopamine (pDA)-based functionalization, onto poly(vinyl chloride) (PVC) surfaces. These surfaces were characterized regarding physicochemical properties and challenged with single and polymicrobial cultures of VAP-relevant bacteria ( Pseudomonas aeruginosa , Acinetobacter baumannii , Klebsiella pneumoniae , Staphylococcus aureus , Staphylococcus epidermidis ) and fungi ( Candida albicans ). The coatings imparted PVC surfaces with a homogeneous morphology, varied wettability, and low roughness. The antimicrobial immobilization via pDA chemistry was still evidenced by infrared spectroscopy. Coated surfaces exhibited sustained CIP/CHX release, retaining prolonged (10 days) activity. CIP/CHX-coated surfaces evidencing no A549 lung cell toxicity displayed better antibiofilm outcomes than CIP or CHX coatings, preventing bacterial attachment by 4.1-7.2 Log 10 CFU/mL and modestly distressing C. albicans . Their antibiofilm effectiveness was endured toward polymicrobial consortia, substantially inhibiting the adhesion of the bacterial populations (up to 8 Log 10 CFU/mL) within the consortia in dual- and even in P. aeruginosa / S. aureus / C. albicans triple-species biofilms while affecting fungal adhesion by 2.7 Log 10 CFU/mL (dual consortia) and 1 Log 10 CFU/mL (triple consortia). The potential of the dual-drug coating strategy in preventing triple-species adhesion and impairing bacterial viability was still strengthened by live/dead microscopy. The pDA-assisted CIP/CHX co-immobilization holds a safe and robust broad-spectrum antimicrobial coating strategy for PVC-ETTs, with the promise laying in reducing VAP incidence.

Electrification and clean hydrogen are promising low-carbon options for decarbonizing industrial process heat, which is an essential target for reducing sector-wide emissions. However, industrial processes with heat demand vary significantly across industries in terms of temperature requirements, capacities, and equipment, making it challenging to determine applications for low-carbon technologies that are technically and economically feasible. In this analysis, we develop a framework for evaluating life cycle emissions, water use, and cost impacts of electric and clean hydrogen process heat technologies and apply it in several case studies for plastics and petrochemical manufacturing industries in the United States. Our results show that industrial heat pumps could reduce emissions by 12-17% in a typical poly(vinyl chloride) (PVC) facility in certain locations currently, compared to conventional natural gas combustion, and that other electric technologies in PVC and ethylene production could reduce emissions by nearly 90% with a sufficiently decarbonized electric grid. Life cycle water use increases significantly in all low-carbon technology cases. The levelized cost of heat of viable low-carbon technologies ranges from 15 to 100% higher than conventional heating systems, primarily due to energy costs. We discuss results in the context of relevant policies that could be useful to manufacturing facilities and policymakers for aiding the transition to low-carbon process heat technologies.

Soluble di-iron monooxygenase (SDIMO) enzymes enable insertion of oxygen into diverse substrates and play significant roles in biogeochemistry, bioremediation and biocatalysis. An unusual SDIMO was detected in an earlier study in the genome of the soil organism Solimonas soli, but was not characterized. Here, we show that the S. soli SDIMO is part of a new clade, which we define as 'Group 7'; these share a conserved gene organization with alkene monooxygenases but have only low amino acid identity. The S. soli genes (named zmoABCD) could be functionally expressed in Pseudomonas putida KT2440 but not in Escherichia coli TOP10. The recombinants made epoxides from C 2 C 8 alkenes, preferring small linear alkenes (e.g. propene), but also epoxidating branched, carboxylated and chlorinated substrates. Enzymatic epoxidation of acrylic acid was observed for the first time. ZmoABCD oxidised the organochlorine pollutants vinyl chloride (VC) and cis-1,2-dichloroethene (cDCE), with the release of inorganic chloride from VC but not cDCE. The original host bacterium S. soli could not grow on any alkenes tested but grew well on phenol and n-octane. Further work is needed to link ZmoABCD and the other Group 7 SDIMOs to specific physiological and ecological roles., (© 2024 The Authors. Environmental Microbiology published by Applied Microbiology International and John Wiley & Sons Ltd.)

Pollution with chloroethenes threaten groundwater resources worldwide. Cis-Dichloroethene (cDCE) and Trichloroethene (TCE) are widespread pollutants that often occur together at contaminated sites, either as primary discharges or as degradation products of anaerobic dechlorination. In this study, comprehensive microcosm experiments were conducted with groundwater samples of seven sites contaminated with chloroethenes. In total, twelve wells with different pollutant concentrations and chloroethene compositions were sampled, and aerobic microcosms including sterile controls were set up. The results revealed interactions as well as interferences between cDCE and TCE. First, co-metabolic cDCE degradation with TCE as growth substrate was detected for the first time in this work. Transformation yields Ty' (molar ratio of co-substrate degraded to primary substrate degraded) of the degradation process were determined and showed a linear relationship with the cDCE/TCE concentration ratio. At low cDCE/TCE ratio, aerobic metabolic TCE degradation can result in complete cDCE removal due to co-metabolic degradation. Secondly, interfering effects were detected at notable cDCE levels resulting in deceleration of TCE degradation and residual concentrations which were also correlating linearly with the cDCE/TCE concentration ratio. These findings are significant for investigating chloroethene contaminated sites and planning remediation strategies. In particular, the efficiency biological remediation methods in the presence of both pollutants can be evaluated more precisely through the knowledge of interactions and interferences. Our study emphasizes that co-contaminants and possible effects of contaminant mixtures on the degradation rates of individual substances should be considered in general., Competing Interests: Declaration of competing interest It is our pleasure to submit the manuscript “Aerobic co-metabolic cis-Dichloroethene degradation with Trichloroethene as primary substrate and effects of concentration ratios” for publication in Chemosphere.Financial support was provided by the German Ministry of Education and Research (BMBF). The funding source had no involvement in the study design, in the collection, analysis, and interpretation of data, in the writing of the report, and in the decision to submit the article for publication. We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with few risk factors identified and no known cure. Gene-environment interaction is hypothesized especially for sporadic ALS cases (90-95%) which are of unknown etiology. We aimed to investigate risk factors for ALS including exposure to ambient air toxics., Methods: This population-based case-control study included 267 ALS cases (from the United States [U.S.] Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry National ALS Registry and Biorepository) and 267 age, sex, and county-matched controls identified via a commercial database. Exposure assessment for 34 ambient air toxicants was performed by assigning census tract-level U.S. Environmental Protection Agency (EPA) 2011 National Air Toxics Assessment (NATA) data to participants' residential ZIP codes. Conditional logistic regression was used to compute adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for individual compounds, chemical classes, and overall exposure. Sensitivity analyses using both conditional logistic regression and Bayesian grouped weighted quartile sum (GWQS) models were performed to assess the integrity of findings., Results: Using the 2011 NATA, the highest exposure quartile (Q4) compared to the lowest (Q1) of vinyl chloride (aOR = 6.00, 95% CI: 1.87-19.25), 2,4-dinitrotoluene (aOR = 5.45, 95% CI: 1.53-19.36), cyanide (aOR = 4.34, 95% CI: 1.52-12.43), cadmium (aOR = 3.30, 95% CI: 1.11-9.77), and carbon disulfide (aOR = 2.98, 95% CI: 1.00-8.91) was associated with increased odds of ALS. Residential air selenium showed an inverse association with ALS (second quartile [Q2] vs. Q1: aOR = 0.38, 95% CI: 0.18-0.79). Additionally, residential exposure to organic/chlorinated solvents (Q4 vs Q1: aOR = 2.62, 95% CI: 1.003-6.85) was associated with ALS., Conclusions: Our findings using the 2011 NATA linked by census tract to residential area provide evidence of increased ALS risk in cases compared to controls for 2,4-dinitrotoluene, vinyl chloride, cyanide, and the organic/chlorinated solvents class. This underscores the importance of ongoing surveillance of potential exposures for at-risk populations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Polymer nanocomposites filled with carbon nanoparticles (CNPs) are a hot topic in materials science. This article discusses the current research on the use of these materials as interfacial electron transfer films for solid contact potentiometric membrane sensors (SC-PMSs). The results of a comparative study of plasticized poly (vinyl chloride) (pPVC) matrices modified with single-walled carbon nanotubes (SWCNTs), fullerenes-C60, and their hybrid ensemble (SWCNTs-C60) are reported. The morphological characteristics and electrical conductivity of the prepared nanostructured composite films are reported. It was found that the specific electrical conductivity of the pPVC/SWCNTs-C60 polymer film was higher than that of pPVC filled with individual nanocomponents. The effectiveness of this composite material as an electron transfer film in a new potentiometric membrane sensor for detecting phenylpyruvic acid (in anionic form) was demonstrated. Screening for this metabolic product of phenylalanine in body fluids is of significant diagnostic interest in phenylketonuria (dementia), viral hepatitis, and alcoholism. The developed sensor showed a stable and fast Nernstian response for phenylpyruvate ions in aqueous solutions over the wide linear concentration range of 5 × 10 -7 -1 × 10 -3 M, with a detection limit of 10 -7.2 M.

Organohalide-respiring bacteria (OHRB)-mediated reductive dehalogenation is promising in in situ bioremediation of chloroethene-contaminated sites. The bioremediation efficiency of this approach is largely determined by the successful colonization of fastidious OHRB, which is highly dependent on the presence of proper growth niches and microbial interactions. In this study, based on two ecological principles (i.e., Priority Effects and Coexistence Theory), three strategies were developed to enhance niche colonization of OHRB, which were tested both in laboratory experiments and field applications: (i) preinoculation of a niche-preparing culture (NPC, being mainly constituted of fermenting bacteria and methanogens); (ii) staggered fermentation; and (iii) increased inoculation of CE40 (a Dehalococcoides -containing tetrachloroethene-to-ethene dechlorinating enrichment culture). Batch experimental results show significantly higher dechlorination efficiencies, as well as lower concentrations of volatile fatty acids (VFAs) and methane, in experimental sets with staggered fermentation and niche-preconditioning with NPC for 4 days (CE40&#95;NPC-4) relative to control sets. Accordingly, a comparatively higher abundance of Dehalococcoides as major OHRB, together with a lower abundance of fermenting bacteria and methanogens, was observed in CE40&#95;NPC-4 with staggered fermentation, which indicated the balanced syntrophic and competitive interactions between OHRB and other populations for the efficient dechlorination. Further experiments with microbial source tracking analyses suggested enhanced colonization of OHRB by increasing the inoculation ratio of CE40. The optimized conditions for enhanced colonization of OHRB were successfully employed for field bioremediation of trichloroethene (TCE, 0.3-1.4 mM)- and vinyl chloride (VC, ∼0.04 mM)-contaminated sites, resulting in 96.6% TCE and 99.7% VC dechlorination to ethene within 5 and 3 months, respectively. This study provides ecological principles-guided strategies for efficient bioremediation of chloroethene-contaminated sites, which may be also employed for removal of other emerging organohalide pollutants.

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Inorganic arsenic and organochlorines are frequently co-occurring contaminants in anoxic groundwater environments, and the bioremediation of their composite pollution has long been a rigorous predicament. Currently, the dechlorination behaviors and stress responses of microbial dechlorination consortia to arsenic are not yet fully understood. This study assessed the reductive dechlorination performance of a Dehalococcoides-bearing microcosm DH under gradient concentrations of arsenate [As(V)] or arsenite [As(III)] and investigated the response patterns of different functional microorganisms. Our results demonstrated that although the dechlorination rates declined with increasing arsenic concentrations in both As(III/V) scenarios, the inhibitory impact was more pronounced in As(III)-amended groups compared to As(V)-amended groups. Moreover, the vinyl chloride (VC)-to-ethene step was more susceptible to arsenic exposure compared to the trichloroethene (TCE)-to-dichloroethane (DCE) step, while high levels of arsenic exposure [e.g. As(III) > 75 μM] can induce significant accumulation of VC. Functional gene variations and microbial community analyses revealed that As(III/V) affected reductive dechlorination by directly inhibiting organohalide-respiring bacteria (OHRB) and indirectly inhibiting synergistic populations such as acetogens. Metagenomic results indicated that arsenic metabolic and efflux mechanisms were identical among different Dhc strains, and variations in arsenic uptake pathways were possibly responsible for their differential responses to arsenic exposures. By comparison, fermentative bacteria showed high potential for arsenic resistance due to their inherent advantages in arsenic detoxification and efflux mechanisms. Collectively, our findings expanded the understanding of the response patterns of different functional populations to arsenic stress in the dechlorinating consortium and provided insights into modifying bioremediation strategies at co-contaminated sites for furtherance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Vinyl chloride (VC) is a dominant carcinogenic residual in many aged chlorinated solvent plumes, and it remains a huge challenge to clean it up. Zerovalent iron (ZVI) is an effective reductant for many chlorinated compounds but shows low VC removal efficiency at field scale. Amendment of ZVI with a carbonaceous material may be used to both preconcentrate VC and facilitate redox reactions. In this study, nitrogen-doped graphene (NG) produced by a simple co-pyrolysis method using urea as nitrogen (N) source, was tested as a catalyst for VC reduction by nanoscale ZVI (nZVI). The extent of VC reduction to ethylene in the presence of 2 g/L of nZVI was less than 1% after 3 days, and barely improved with the addition of 4 g/L of graphene. In contrast, with amendment of nZVI with NG produced at pyrolysis temperature (PT) of 950 °C, the VC reduction extent increased more than 10-fold to 69%. The reactivity increased with NG PT increasing from 400 °C to an optimum at 950 °C, and it increased linearly with NG loadings. Interestingly, N dosage had little effect on reactivity if NG was produced at PT of 950 °C, while a positive correlation was observed for NG produced at PT of 600 °C. XPS and Raman analyses revealed that for NG produced at lower PT (<800 °C) mainly the content of pyridine-N-oxide (PNO) groups correlates with reactivity, while for NG produced at higher PT up to 950 °C, reactivity correlates mainly with N induced structural defects in graphene. The results of quenching and hydrogen yield experiments indicated that NG promote reduction of VC by storage of atomic hydrogen, thus increasing its availability for VC reduction, while likely also enabling electron transfer from nZVI to VC. Overall, these findings demonstrate effective chemical reduction of VC by a nZVI-NG composite, and they give insights into the effects of N doping on redox reactivity and hydrogen storage potential of carbonaceous materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Chloroethenes (CEs) as common organic pollutants in soil could be attenuated via abiotic and biotic dechlorination. Nonetheless, information on the key catalyzing matter and their reciprocal interactions remains scarce. In this study, FeS was identified as a major catalyzing matter in soil for the abiotic dechlorination of CEs, and acetylene could be employed as an indicator of the FeS-mediated abiotic CE-dechlorination. Organohalide-respiring bacteria (OHRB)-mediated dechlorination enhanced abiotic CEs-to-acetylene potential by providing dichloroethenes (DCEs) and trichloroethene (TCE) since chlorination extent determined CEs-to-acetylene potential with an order of trans -DCE > cis -DCE > TCE > tetrachloroethene/PCE. In contrast, FeS was shown to inhibit OHRB-mediated dechlorination, inhibition of which could be alleviated by the addition of soil humic substances. Moreover, sulfate-reducing bacteria and fermenting microorganisms affected FeS-mediated abiotic dechlorination by re-generation of FeS and providing short chain fatty acids, respectively. A new scenario was proposed to elucidate major abiotic and biotic processes and their reciprocal interactions in determining the fate of CEs in soil. Our results may guide the sustainable management of CE-contaminated sites by providing insights into interactions of the abiotic and biotic dechlorination in soil.

As a group of pollutants listed in the Stockholm Convention, polychlorinated biphenyls (PCB) should be eliminated and their releases should be controlled. For this purpose, a complete PCB emission inventory is urgently required. Current unintentional releases of PCB were dominantly focused on waste incineration and non-ferrous metal production industries. The formation of PCB in chlorinated chemical manufacturing processes is poorly understood. In this study, occurrences and inventory of dioxin-like PCB (dl-PCB) in three typical chemical manufacturing processes, including chlorobenzene and chloroethylene production processes, were investigated. The bottom residues, which were high boiling point by-products after rectification tower, contained higher concentration of PCB than other stage samples in monochlorobenzene production and trichloroethylene production processes. The PCB concentrations were as high as 1.58 ng/mL and 152.87 ng/mL, respectively, which should be further concerned. The toxic equivalent quantities (TEQ) of dl-PCB in monochlorobenzene, trichloroethylene, and tetrachloroethylene products were 0.25 μg TEQ/t, 1.14 μg TEQ/t, and 5.23 μg TEQ/t, respectively. The mass concentration and TEQ of dl-PCB determined in this research can be used for the further development of dl-PCB emission inventory from these chemical manufacturing industries. In addition, temporal and spatial trends of PCB releases from typical chemical manufacturing processes from 1952 to 2018 in China were clarified. The releases increased rapidly in the latest two decades and presented an expansion tendency from the southeast coastal areas to northern and central areas. The continuing upward trend for the output and the high dl-PCB TEQ of chloroethylene indicated significant releases of PCB from chemical manufacturing processes and should receive more attention., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Environmental vinyl chloride (VC) exposure may result in serious acute and chronic dermatological conditions. Because existing literature largely focuses on exposures in occupational settings, a gap persists in our understanding of the medical consequences of large-scale chemical spills., Objective: This study aims to examine the potential dermatological manifestations of VC exposure in the context of industrial spills and other environmental disasters and to highlight the public health and justice implications of such releases., Methods: In this narrative review, relevant evidence-based, peer-reviewed scientific sources, gray literature, and media reports were identified via searches of search PubMed and Google using predetermined keyword search terms related to VC, VC spills and releases, train derailment, cutaneous disease, public health, and vulnerable and marginalized populations., Results: Contact dermatitis and frostbite may arise acutely, highlighting the importance of swift decontamination. Long-term manifestations from chronic VC exposure due to persistence in environmental reservoirs include Raynaud disease, sclerodermatous skin changes, acro-osteolysis, and cutaneous malignancies. The clinical severity of cutaneous manifestations is influenced by individual susceptibility as well as duration, intensity, and route of exposure. Additionally, chemical releases of VC more frequently impact Communities of Color and those of lower socioeconomic status, resulting in greater rates of exposure-related disease., Conclusions: With environmental release events of hazardous chemicals becoming increasingly common and because the skin has increased contact with environmental toxins relative to other organs, an urgent need exists for a greater understanding of the overall short- and long-term health impacts of large-scale, toxic exposures, underscoring the need for ongoing clinical vigilance. Dermatologists and public health officials should also aim to better understand the ways in which the disproportionate impacts of hazardous chemical exposures on lower-income and minority populations may exacerbate existing health disparities. Herein, we describe the health implications of toxic releases with particular consideration paid to marginalized and vulnerable populations. In addition to legal and regulatory frameworks, we advocate for improved public health measures, to not only mitigate the risk of environmental catastrophes in the future, but also ensure timely and effective responses to them., (©Rachel S Goodman, Lavanya Mittal, Eva Rawlings Parker. Originally published in JMIR Dermatology (http://derma.jmir.org), 07.09.2023.)

Poly(vinyl chloride) (PVC) was reinforced with electrospun glass nanofibres (EGN) to develop photochromic and afterglow materials such as smart windows and anti-counterfeiting prints. A colourless electrospun glass nanofibres@poly(vinyl chloride) (EGN@PVC) sheet was prepared by physical integration of lanthanide-doped aluminate nanoparticles (LANP). The low concentrations of LANP in the photochromic and photoluminescent EGN@PVC hybrids displayed fluorescence emission with instant reversibility. EGN@PVC with the highest phosphor concentrations showed persistent phosphorescence emission with slow reversibility. Based on the results of the Commission Internationale de l'éclairage Laboratory and luminescence spectroscopy, the translucent EGN@PVC samples became green in the presence of ultraviolet illumination and greenish-yellow in the absence of light. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses, the morphological study of EGN and LANP showed diameters of 75-95 and 11-19 nm, respectively. The morphology of the EGN@PVC substrates was studied using SEM, X-ray fluorescence, and energy-dispersive X-ray spectroscopy. The mechanical characteristics of PVC were enhanced by reinforcement with EGN as a roughening agent. When comparing the scratching resistance of LANP-free substrate to photoluminescent EGN@PVC substrates, it was observed that the latter was much superior. The photoluminescence spectra were reported to have an emission peak at 519 nm when excited at 365 nm. These findings demonstrated that the luminous transparent EGN@PVC composites had improved superhydrophobic and UV-blocking characteristics., (© 2023 John Wiley & Sons Ltd.)

Occupational acro-osteolysis pertains to bone resorption of the distal phalanges of the hands and feet among workers with vinyl chloride exposure. We report the case of a Filipino man with osteolysis of the distal phalanges of the hands initially considered to have systemic sclerosis. The patient had gradual shortening of the fingers, thickening of the skin over the extremities, and hypopigmented patches over a span of more than 20 years. His lower extremities presented with non-pitting edema, skin thickening, and neuropathy, without shortening of the digits. Difficulty of ambulation was apparent due to the development of feet inversion. Radiographic findings of the hands and feet included resorption of distal phalanges, erosive and sclerotic changes, and narrowed joint spaces. Other conditions considered were Hansen's disease, skeletal tuberculosis, and diabetic neuropathic arthropathy, which were eventually ruled out. The final diagnosis was occupational acro-osteolysis secondary to vinyl chloride exposure. The patient underwent serial total contact casting of the bilateral lower extremities to relieve bipedal edema and to reposition the feet. This case emphasizes the significance of investigating a patient's occupational history and highlights a rare sequela of exposure to a commonly used chemical agent in the manufacture of polyvinyl chloride products., Competing Interests: Both authors declared no conflicts of interest., (© 2023 Acta Medica Philippina.)

In situ bioremediation of chlorinated compounds such as perchloroethylene (PCE) and trichloroethylene (TCE) through enhanced reductive dechlorination (ERD) requires appropriate growth conditions for organohalide-respiring bacteria (OHRB). One of the most important factors controlling OHRB metabolism is groundwater pH. Dehalococcoides spp. (DHC) growth may be inhibited when pH is lower than 6.0, which can lead to the accumulation of toxic daughter compounds including cis-dichloroethylene (cDCE) and vinyl chloride (VC). Aquifer pH may decline as HCl is released during reductive dechlorination and from substrate fermentation to fatty acids and carbonic acid. In this article, we demonstrate that using proper pH adjustment and control in situ is an appropriate strategy to achieve complete ERD (i.e., complete conversion of PCE and TCE to nontoxic ethylene) in remediation sites with inherently low pH values and/or low buffering capacity. To analyze the effectiveness of this approach, field monitoring results are presented for a challenging site containing high concentrations of PCE and TCE (>10 000 µg/L and >1000 µg/L, respectively) and low aquifer pH (~4.9). Addition of a bioaugmentation culture, emulsified vegetable oil (EVO), and a colloidal buffer (CoBupH TM ) to increase pH, stimulated rapid conversion of PCE and TCE to cDCE and VC. However, further conversion of cDCE and VC was very limited. To stimulate complete conversion to ethylene, additional CoBupH TM and nutrients were injected, resulting in a rapid increase in metabolic rates, and maintained the aquifer pH at ~6.5 for more than five years, thus demonstrating that complete ERD can be achieved in sites with similar characteristics. Proper pH adjustment and control is needed to limit the accumulation of toxic intermediates, maintaining in situ bioremediation as an efficient, affordable, and environmentally friendly option to treat chlorinated compounds. Integr Environ Assess Manag 2023;19:943-948. © 2022 SETAC., (© 2022 SETAC.)

Alterations in physiological processes in pancreas have been associated with various metabolic dysfunctions and can result from environmental exposures, such as chemicals and diet. It was reported that environmental vinyl chloride (VC) exposure, a common industrial organochlorine and environmental pollutant, significantly exacerbated metabolic-related phenotypes in mice fed concurrently with high-fat diet (HFD) but not low-fat diet (LFD). However, little is known about the role of the pancreas in this interplay, especially at a proteomic level. The present study was undertaken to examine the protein responses to VC exposure in pancreas tissues of C57BL/6J mice fed LFD or HFD, with focus on the investigation of protein expression and/or phosphorylation levels of key protein biomarkers of carbohydrate, lipid, and energy metabolism, oxidative stress and detoxification, insulin secretion and regulation, cell growth, development, and communication, immunological responses and inflammation, and biomarkers of pancreatic diseases and cancers. We found that the protein alterations may indicate diet-mediated susceptibility in mouse pancreas induced by HFD to concurrent exposure of low levels of inhaled VC. These proteome biomarkers may lead to a better understanding of pancreas-mediated adaptive or adverse response and susceptibility to metabolic disease., (Published by Oxford University Press on behalf of the Society of Toxicology 2023.)

Crystal engineering of metal oxide supports represents an emerging strategy to improve the catalytic performance of noble metal catalysts in catalytic oxidation of chlorinated volatile organic compounds (CVOCs). Herein, Pt catalysts on a TiO 2 support with different crystal phases (rutile, anatase, and mixed phase (P25)) were prepared for catalytic oxidation of 1,2-dichloroethane (DCE). The Pt catalyst on P25-TiO 2 (Pt/TiO 2 -P) showed optimal activity, selectivity, and stability, even under high-space velocity and humidity conditions. Due to the strong interaction between Pt and P25-TiO 2 originating from the more lattice defects of TiO 2 , the Pt/TiO 2 -P catalyst possessed stable Pt 0 and Pt 2+ species during DCE oxidation and superior redox property, resulting in high activity and stability. Furthermore, the Pt/TiO 2 -P catalyst possessed abundant hydroxyl groups, which prompted the removal of chlorine species in the form of HCl and significantly decreased the selectivity of vinyl chloride (VC) as the main byproduct. On the other hand, the Pt/TiO 2 -P catalyst exhibited a different reaction path, in which the hydroxyl groups on its surface activated DCE to form VC and enolic species, besides the lattice oxygen of TiO 2 for the Pt catalysts on rutile and anatase TiO 2 . This work provides guidance for the rational design of catalysts for CVOCs.

A strictly anaerobic, organohalide-respiring bacterium, designated strain GP T , was characterized using a polyphasic approach. GP T 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 T 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 2 and formate serve as electron donors for organohalide respiration in the presence of acetate as carbon source. Major cellular fatty acids include C 16 : 0 , C 18 : 1 ω9 c , C 16 : 1 , C 14 : 0 and C 18 : 0 . On the basis of 16S rRNA gene phylogeny, GP T is most closely related to Dehalogenimonas formicexedens NSZ-14 T and Dehalogenimonas alkenigignens IP3-3 T 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 T in previously described species of the genus Dehalogenimonas with validly published names. On the basis of phylogenetic, physiological and phenotypic traits, GP T represents a novel species within the genus Dehalogenimonas , for which the name Dehalogenimonas etheniformans sp. nov. is proposed. The type strain is GP T (= JCM 39172 T = CGMCC 1.17861 T ).

Road accidents are not infrequent everywhere in the world, but when they involve poisonous and dangerous chemical compounds, they represent a hazard and an issue for public health. In this commentary, we briefly review a recent East Palestine event and one of the chemicals primarily involved with a predisposition to initiate a carcinogenetic process. The author reviewed, as a consultant, numerous chemical compounds for the International Agency for Research on Cancer, a trusted agency of the World Health Organization. Something is looming over the territories of East Palestine, Ohio, United States, draining water from the soil. We speculate that there is a dark and opprobrious fate for this area of the United States due to the potential increase in cases of pediatric hepatic angiosarcoma, which will also be revised in this commentary.

Chlorinated paraffins (CPs) are used in many products, including soft poly(vinyl chloride) curtains, which are used in many indoor environments. Health hazards posed by CPs in curtains are poorly understood. Here, chamber tests and an indoor fugacity model were used to predict CP emissions from soft poly(vinyl chloride) curtains, and dermal uptake through direct contact was assessed using surface wipes. Short-chain and medium-chain CPs accounted for 30% by weight of the curtains. Evaporation drives CP migration, like for other semivolatile organic plasticizers, at room temperature. The CP emission rate to air was 7.09 ng/(cm 2 h), and the estimated short-chain and medium-chain CP concentrations were 583 and 95.3 ng/m 3 in indoor air 21.2 and 172 μg/g in dust, respectively. Curtains could be important indoor sources of CPs to dust and air. The calculated total daily CP intakes from air and dust were 165 ng/(kg day) for an adult and 514 ng/(kg day) for a toddler, and an assessment of dermal intake through direct contact indicated that touching just once could increase intake by 274 μg. The results indicated that curtains, which are common in houses, could pose considerable health risks through inhalation of and dermal contact with CPs.

In this work, chloride ions were used as conservative tracers and supplemented with conservative amounts of chloroethenes (PCE, TCE, Cis-DCE, 1,1-DCE), chloroethanes (1,1,1-TCA, 1,1-DCA), and the carbon isotope ratios of certain compounds, the most representative on the sites studied, which is a novelty compared to the optimization methods developed in the scientific literature so far. A location of the potential missing sources is then proposed in view of the balances of the calculated mixing fractions. A test of the influence of measurement errors on the results shows that the uncertainties in the calculation of the mixture fractions are less than 11%, indicating that the source identification method developed is a robust tool for identifying sources of chlorinated solvents in groundwater., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

A reliable analytical method has been developed to quantify poly(vinyl chloride) (PVC) in environmental samples. Quantification was conducted via combustion ion chromatography (C-IC). Hydrogen chloride (HCl) was quantitatively released from PVC during thermal decomposition and trapped in an absorption solution. Selectivity of the marker HCl in complex environmental samples was ensured using cleanup via pressurized liquid extraction (PLE) with methanol at 100 °C (discarded) and tetrahydrofuran at 185 °C (collected). Using this method, recoveries of 85.5 ± 11.5% and a limit of quantification down to 8.3 μg/g were achieved. A variety of hard and soft PVC products could be successfully analyzed via C-IC with recoveries exceeding >95%. Furthermore, no measurable overdetermination was found for various organic and inorganic matrix ingredients, such as sodium chloride, sucralose, hydroxychloroquine, diclofenac, chloramphenicol, triclosan, or polychlorinated biphenyls. In addition, sediments and suspended particular matter showed PVC concentrations ranging up to 16.0 and 220 μg/g, respectively. However, the gap between determined polymer mass and particle masses could be significant since soft PVC products contain plasticizers up to 50 wt %. Hence, the results of the described method represent a sum of all chlorine-containing polymers, which are extractable under the chosen conditions.

Vulcanized acrylonitrile-butadiene rubber (NBR)/poly (vinyl chloride) (PVC) blends are mainly served as insulation rubber-plastic materials. However, methods to reuse the waste NBR/PVC composites lack research. Here, we found that the mechanochemically modified waste NBR/PVC composites powders (WNPP) could be an alternative to fresh NBR. According to the results, the optimal replacement amount of WNPP for NBR was 20%, and the highest feasible proportion was 40%. WNPP treated by solid-state shear milling technology (S 3 M) would have a high degree of desulfurization, and the cross-linked chains within WNPP would be transformed into free chains. While co-vulcanizing, the sulfur agents and heat would induce the free chains of WNPP to react with the polymer chains of the NBR substrate, thereby generating dangling chains to form a robust interfacial layer. It was beneficial for the improvement of the mechanical properties of reclaimed products. And the strain of the excellent recycled sample (20C) reached 707%. Moreover, the modified WNPP in the co-vulcanized rubber represented heterogeneity because of the internal residual crosslinked network and the not-melting PVC plastic phase. Although the heterogeneity of WNPP damaged the continuity of the NBR matrix, it also brought a better hysteresis loss capability to the composite. In conclusion, this work expanded the mechanochemical application scope in recycling NBR/PVC wastes., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ‘Shibing Bai reports financial support was provided by National Key Research and Development Program of China. Shibing Bai reports financial support was provided by National Natural Science Foundation of China.’, (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A novel one step route for the synthesis of tannic acid, lipoic acid and menthol functionalized polyvinyl chloride, PVC, (PVC-Tann, PVC-Lip, PVC-Mnt) and chlorinated polypropylene, PP-Cl, (PP-Mnt, PP-Lip) was applied imparting antioxidative properties to the newly-formed materials. The resulting modified polymers were characterized by stress-strain mechanical measurement, 1 H NMR, gel permeation chromatography (GPC) and thermogravimetric (TGA) analysis. Linseed oil, owing to its high linolenic acid content, was used to track the autoxidation process. The chloride functional groups were reacted with the hydroxyl/carboxylic acid of the natural compounds in the presence of a base. Linseed oil was poured into the natural compound functionalized PVC covered Petri dish to undergo autoxidation under white light. Each of the PVC- and PP-Cl-based polymers was active in delaying autoxidation. The PP-Mnt series and PP-Lip polymers all delayed autoxidation by 8 days over the PP-Cl precursor material. The autoxidation process was further confirmed by monitoring peroxide formation in the exposed linseed oil samples through differential scanning calorimeter (DSC) analysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Cross-linked acrylonitrile-butadiene rubber (NBR)/poly(vinyl chloride) (PVC) blends are extensively served as commercial insulation foams. However, methods to reclaim the wasted NBR/PVC composites are usually inappropriate, causing severe pollution. Herein, we reported that the waste NBR/PVC composites powders (WNPP) with high thermal stability and degree of reclaiming were prepared by solid-state shear milling technology (S 3 M). Furthermore, the reclaimed products via thermoplastic re-processing had excellent mechanical properties, and the optimal stress and strain were increased by 208.2 % and 269.4 %, respectively, compared with the products made from virgin scraps. Through the investigation of each sample's molecular chains and thermal properties, it was found that when the cross-linked polar rubber-plastic composites are reclaimed, the molecular chains of the rubber phase would be close to each other. The interaction among polar groups would be enhanced, which is the main contributing factor limiting the movability of the polymer chains. And the interaction between the polar rubber and plastic phases would also increase, which is beneficial for the compatibility of the two phases. Moreover, there is a phase separation between the de-crosslinked continuous phase and the residual cross-linked network region for the re-processing products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Quantifying VOC transport from contaminated groundwater to streams is challenging and important for understanding off-site migration of VOCs, cross-media contamination (groundwater to surface water and eventually air), and potential impacts on downstream ecosystems and human populations. A streambed point sampling approach was used to quantify fluxes of water and 14 VOCs from groundwater to an urban stream in North Carolina, USA, during summer (June 2015) and winter (January 2016). The approach is unique in coupling measurements of vertical hydraulic conductivity, vertical hydraulic head gradient, and groundwater VOC concentration at each individual sampling point, reducing or eliminating some potential concerns with other Darcian methods for quantifying VOC inputs to streams. Most results were consistent with discharge of two main VOC plumes on opposite sides of the stream. Plume 1 from the west side was dominated by cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC) at mean concentrations of 19 and 11 μg L -1 , respectively. Plume 2 from the east side was dominated by benzene (mean concentration 56 μg L -1 ). Plume 2 was not previously known, and the improved sampling approach allowed VOC discharge from both plumes to be quantified simultaneously. For 13 of the 14 detected VOCs, the mean VOC flux from groundwater to the stream (f VOC ) was higher in January 2016 than in June 2015, mainly because groundwater flux was higher in January. The only exception was cDCE, the most abundant VOC in Plume 1, which had mean f VOC values of 9.8 and 9.5 mg m -2 d -1 in June 2015 and January 2016, respectively. Benzene was the most abundant VOC in Plume 2 and had mean f VOC values of 11 and 37 mg m -2 d -1 in June 2015 and January 2016, respectively. High groundwater flux drove almost all the occurrences of high VOC flux. For a given VOC, the flow-weighted mean concentration (with each VOC concentration weighted by the upward groundwater flux at the VOC sampling point) was generally larger than the unweighted mean concentration. Thus, flow-weighting of concentrations gave a more accurate indication of the average VOC concentration in net groundwater discharge to the stream. An estimate of total VOC mass discharge from groundwater to the study reach of the stream, 3.6 kg of VOC per year, was based on the f VOC results and streambed area in the reach. The bulk of this discharge was due to benzene, cDCE, and VC, with individual mass discharges of 2.1, 0.83, and 0.40 kg yr -1 , respectively. Estimates of maximum potential VOC degradation in the streambed suggest that the 3.6 kg yr -1 estimate of mass discharge was not sensitive to potential degradation of VOCs in the streambed sediments above the groundwater sampling depth., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Trichloroethylene (TCE) was once a widely applied industrial solvent, but is now an infamous contaminant in groundwater. Although anaerobic reductive dechlorination is considered a greener remediation approach, the accumulation of toxic intermediates, such as vinyl chloride (VC), and a longer remediation period are highly concerning. Biostimulation and bioaugmentation have been developed to solve these problems. The former method may not be effective, and the latter may introduce foreign genes. Here, we propose a new approach by applying environmental stresses to reshape the indigenous microbiome. In this study, by using the Taguchi method, the effects of heating, pH, salinity, and desiccation were systematically examined. The optimum conditions were defined as 50 °C, pH 9, 3.50% salinity (w/v), and 21% volumetric water content (θ W ). The top performing group, G7, can complete the conversion of 11.81 mg/L TCE into ethene in 3.0 days with a 1.23% abundance of Dehalococcoides mccartyi 195 (Dhc 195). Redundancy analysis confirmed that temperature and salinity were the predominant factors in reorganizing the microbiomes. The microbiome structure and its effectiveness can last for at least 90 d. The repetitive selection conditions and sustainable degradation capability strongly supported that microbiome reengineering is feasible for the rapid bioremediation of TCE-contaminated environmental matrices., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The corresponding author, Shu-Chi Chang, has received a patent on heat selection of more effective TCE-degrading mixed cultures in Taiwan based on his research published in 2021 (Chan et al., 2021). The invention patent ID is I684575., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objective: To comprehensively evaluate the effectiveness of improvement of protective facilities in a vinyl chloride monomer(VCM) on promotion toward health status of occupational exposed group and safety production at poly-vinyl chloride(PVC) by comparing the liver function indicators and inspection result before and after the improvement, and to analyze the possible influential factors., Methods: The information collection concerning facilities improvement in 2013 and 2016, identification toward critical controlling points, data or detection result from occupational on-site survey and physical examination were originated in July 2020, and 227 VCM exposed workers and 179 others without chemical reagents exposure history from production factory with calcium carbide process in Tianjin City were selected as objects. The effectiveness toward improvement of protective facilities in critical controlling points that occupational exposed workers usually involve in were evaluated through comparison toward VCM concentration result, thiodiglycolic acid(TDGA) content in urine, indicators on liver function and biochemistry and liver ultrasound. At the mean time, both binary Logistic regression analysis was used to screen the possible factors that contributed to abnormal symptoms and single dependent variable general linear regression model was used to find out the mutual interaction among influential factors., Results: Prior to improvement on protective facilities, the C&#95;(TWA)of VCM exposed by all 8 positions in G had exceeded 1 to 2 folds of occupational exposure limit(OEL=10 mg/m~3) and the position of synthetic operator and field sampling man were ones exposed to 1, 2-DCE with the range from 50% to 1 OEL, others hazard factors were found to meet relative OELs. Next, the content of TDGA in urine of exposed group was found to correlate strongly to the average concentration of VCM(r=0.79, P&lt;0.05), and result of TDGA content, alanine aminotransferase(ALT), γ-glutamyl transpeptidase(GGT) and abnormal rate toward liver ultrasound test in exposed group were much higher than ones in control group with significant differences(P&lt;0.05 or P&lt;0.001). By contrast, after the improvement, the exposure level toward all identified hazard factors were declined to meet OEL levels with significant differences in TDGA content, and result of ALT, GGT and abnormal rates toward symptoms in liver ultrasound test such as liver calcification with thickened liver echo, peripheral fibrosis of the liver, multiple hepatic cysts were markedly lower than ones before improvement and still were higher than ones in control group(P&lt;0.05 or P&lt;0.001). Further, parameters of gender, length of employment, weekly contact time, VCM exposed level, TDGA content were all important contributing factors to abnormal symptoms in liver ultrasound test before and after improvement on protective facilities(P&lt;0.05 or P&lt;0.001), in which a significant interaction effect between gender and length of employment(F=4.028, P=0.044), weekly contact time and TDGA content(F=2.183, P=0.046) in urine were found in contribution analysis to abnormal symptoms in liver ultrasound test(P&lt;0.05)., Conclusion: The improvement measure carried out in VCM facilities by this PVC production factories with calcium carbide process effectively reduced the ambient concentration of hazard factors mainly led by VCM, but workers might still be at risk of liver injury even under VCM exposure at relative lower level, which may referred to factors of long weekly contact time, long length of employment and high fat diet.

Chlorinated ethenes (CEs) are common and persistent contaminants of soil and groundwater. Their degradation is mostly driven by a process of bacterial reductive dechlorination (also called organohalide respiration) in anaerobic conditions. This study summarizes the outcomes of the long-term in-situ application of glycerol for the enhanced reductive dechlorination of CEs on a highly contaminated site. Glycerol injection resulted in an almost immediate increase in the abundance of fermentative Firmicutes, which produce essential sources of carbon (acetate) and electrons (H 2 ) for organohalide-respiring bacteria (OHRB) and change groundwater conditions to be suitable for OHRB growth. The decreased redox potential of groundwater promoted also the proliferation of sulfate-reducing bacteria, which compete for electron donors with OHRB but at the same time support their growth by producing essential corrinoids and acetate. A considerable increase in the abundance of OHRB Dehalococcoides, concurrently with vinyl chloride (VC) reductase gene levels, was revealed by real time polymerase chain reaction (qPCR) method. Consistent with the shifts in bacterial populations, the concentrations of pollutants tetrachloroethylene and trichloroethylene decreased during the monitoring period, with rising levels of cis-1,2-dichloroethylene, VC, and most importantly, the final CE degradation products: ethene and ethane. Our study implies the importance of syntrophic bacterial interactions for successful and complete CE degradation and evaluates glycerol as convenient substrate to enhance reductive dechlorination and as an effective source of electrons for OHRB., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Microplastics have been investigated over the last decade as potential transport vectors for other pollutants. However, the specific role of plastic aging, in which plastics change their characteristics over time when exposed to environmental agents, has been overlooked. Therefore, sorption experiments were herein conducted using virgin and aged (by ozone treatment or rooftop weathering) microplastic particles of LDPE - low-density polyethylene, PET - poly(ethylene terephthalate), or uPVC - unplasticized poly(vinyl chloride). The organic micropollutants (OMPs) selected as sorbates comprise a diversified group of priority substances and contaminants of emerging concern, including pharmaceutical substances (florfenicol, trimethoprim, diclofenac, tramadol, citalopram, venlafaxine) and pesticides (alachlor, clofibric acid, diuron, pentachlorophenol), analyzed at trace concentrations (each ≤100 μg L -1 ). Sorption kinetics and equilibrium isotherms were obtained, as well as the confirmation that the aging degree of microplastics plays a major role in their sorption capacities. The results show an increased sorption of several OMPs on aged microplastics when compared to pristine samples, i.e. the sorption capacity increasing from one or two sorbed substances (maximum 3 μg g -1 per sorbate) up to nine after aging (maximum 10 μg g -1 per sorbate). The extent of sorption depends on the OMP, polymer and the effectiveness of the aging treatment. The modifications (e.g. in the chemical structure) between virgin and aged microplastics were linked to the increased sorption capacity of certain OMPs, allowing to better understand the different affinities observed. Additionally, phytotoxicity tests were performed to evaluate the mobility of the OMPs sorbed on the microplastics and the potential effects (on germination and early growth) of the combo on two species of plants (Lepidium sativum and Sinapis alba). These tests suggest low or no phytotoxicity effect under the conditions tested but indicate a need for further research on the behavior of microplastics on soil-plant systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Microplastic (MP) pollution has increasingly become an enormous global challenge due to the ubiquity and uncertain environmental performance, especially for nano- and micro- sized MPs. In this work, the performance and mechanisms in coagulation of 100 nm-5.0 μm sized polystyrene particles using an etherified starch-based coagulant (St-CTA) assisted by polysilicic acid (PSA) were systematically studied on the basis of the changes in MPs removal rates under various pH levels and in the presence of different coexisting inorganic and organic substances, zeta potentials of supernatants, and floc properties. St-CTA in conjunction with PSA had a high performance in coagulation of nano- and micro- sized MPs from water with a lower optimal dose and larger and compacter flocs. Besides, the MPs removal rate can be improved in acidic and coexisting salt conditions. The efficient performance in removal of MPs by this enhanced coagulation was owing to the synergic effect, that is, the effective aggregation of MPs through the charge neutralization of St-CTA followed by the efficient netting-bridging effect of PSA. The effectiveness of this enhanced coagulation was further confirmed by removal of two other typical nano-sized MPs, such as poly(methyl methacrylate) and poly(vinyl chloride), from different water sources including tap water, river water, and sludge supernatant from a sewage treatment plant. This work provided a novel enhanced coagulation technique that can effectively remove nano- and micro- sized MPs from water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this work, a method to increase the dispersion of graphene (GN) in the matrix of rigid poly(vinyl chloride) (PVC) by using a natural plant extract from Curcuma longa L. (CE) is proposed. Currently, despite the increasing number of reports on the improvement of GN dispersion in PVC blends, still there is a need to find environmentally friendly and economical dispersion stabilizers. We proposed a stabilizer that can be easily obtained from a plant offering thermal stability and high effectiveness. PVC/GN nanocomposites stabilized with the proposed extract were investigated by SEM, AFM (structure), TGA, and Congo red test (thermal properties). Additionally, static and dynamic mechanical properties and electrical resistivity were measured. The use of CE as a graphene dispersant improved its dispersion in the PVC matrix, influenced tensile properties, increased the storage modulus and glass transition temperature, and extended the thermal stability time of nanocomposites. In this work, a CE extract is proposed as an efficient eco-friendly additive for the production of nanocomposites with an improved homogeneity of a nanofiller in the matrix and promising characteristics.

Objective: To investigate the detection of occupational health for vinyl chloride workers in Tianjin. Methods: In this study, we have collected data from 7 companies with vinyl chloride hazards in 16 districts of Tianjin. Finally, the occupational health surveillance data of 478 vinyl chloride-exposed workers were included in the analysis. Quantitative data was tested for normality. If the data conforms to the normal distribution, using the Mean±SD for statistical description, and t test for statistical analysis. If the data does not conform to the normal distribution, using Median ( Q (1), Q (100)) for statistical description, rank sum test for statistical analysis. The qualitative data was described by composition ratio, and the chi-square test was used for statistical analysis. The logistic regression was used to assess the impact on suspected occupational disease and occupational contraindication from personal general conditions, occupational history, company information. Results: The abnormal detection rate of vinyl chloride monomer workers in Binhai New Area was higher than that in other areas (χ(2)=5.20, P =0.023). The abnormal detection rate of vinyl chloride monomer workers in non manufacturing industries was higher than that in manufacturing industries (χ(2)=7.74, P =0.005). The abnormal detection rate of vinyl chloride monomer workers in domestic enterprises was higher than that in foreign invested enterprises (χ(2)=22.38, P <0.01). Compared with the normal group of vinyl chloride monomer workers, the abnormal group of workers was older and had longer working years, The difference was statistically significant ( Z =-3.32, -3.54, P =0.001, <0.01). The employer of vinyl chloride monomer workers is in Binhai New Area, the economic type is domestic funded enterprise, the industry is classified as non manufacturing industry, the age is more than 40 years old, and the length of service is more than 20 years old, which is the influencing factor for workers to detect abnormalities ( OR =1.875, 95% CI : 1.279~2.749; OR =1.657, 95% CI : 1.071~2.563; OR =3.562, 95% CI : 2.057~6.170; OR =2.166, 95% CI : 1.245~3.768; OR =1.968, 95% CI : 1.345~2.879, all P <0.05) . Conclusion: To protect the health of workers and prevent occupational diseases, the management of vinyl chloride exposure on production process, especially in domestic enterprise, should be improved. Also, better occupational health surveillance should be provided to female workers.

In some cases, blends containing PVC and LLDPE show low compatibility. Adding styrene-butadiene rubber to the PVC/LLDPE mixtures leads to a noticeable increase in tensile strength and compatibility of the blends. Also, an improvement in tensile strength is observed after incorporating SBR compatibilizer resulting in entirely different gamma irradiation doses. Without a compatibilizer, the mixture exhibits a distributed PVC and LLDPE phase with variable sizes and shapes; even a sizable portion of the domains resemble droplets. Styrene butadiene rubber (SBR) and gamma radiation make mixtures of (PVC/LLDPE) more compatible. The SEM study of the blends demonstrated that adding the compatibilizer resulted in finer blend morphologies with less roughness. At the same time, gamma irradiation reduced this droplet and gave a more smooth surface. Poly(vinyl chloride) (PVC) was chemically modified with four different amino compounds, including ethylene diamine (EDA), aniline (An), p-anisidine (pA) and dimethyl aniline (DMA) for improving the electric conductivity and oil removal capability of the blend polymer. All ionomers were prepared by nucleophilic substitution in a solvent/non-solvent system under mild conditions. This work novelty shows a sustainable route for producing oil adsorption materials by recycling plastic waste. After the amination process of poly(vinyl chloride) the oil adsorption was significantly enhanced., (© 2022. The Author(s).)

Rigid semi-Interpenetrated Polymer Network (semi-IPN) foam based on poly(vinyl chloride) (PVC) and crosslinked polyurea/isocyanurate are complex materials that at present are not recyclable. They are used in many fields, including wind blade cores. In this work we studied the depolymerization of the crosslinked portion of the foam under glycolysis conditions for the separation and reuse of the individual components. Reaction products were characterized by FT-IR, NMR, solvent solubility, DSC, elemental analysis, titration of amine and hydroxyl groups and rheology measurements. Triisocyanurates and urea moieties were synthesized and used as model compounds. Glycolysis conditions were optimized to maximize depolymerization while minimizing PVC degradation. The parameters studied were reaction time (8 min to 3 h), temperature (155 to 200 °C), catalyst (potassium acetate or dibutyl tin dilaurate (DBTL)), glycol (ethylene glycol, 1,4 butanediol, diethylene glycol, dipropylene glycol, polyethylene glycol), as well as the effect of PVC thermal stabilizers such as hindered phenols and organo-phosphites. The results showed that the optimal reaction condition for foam glycolysis is 165-175 °C for 20-30 min, using DBTL as catalyst and including thermal stabilizers. No drastic difference was noticed by the kind of glycol used, except for PEG that led to greater PVC degradation. The greatest part of the crosslinked portion (≥90 %) was depolymerized and the result were mainly hydroxyl- and in minor amount amine- terminated oligomers. The recovered PVC (purity roughly 90 %) had a low degree of degradation and a viscosity suitable for its processing as thermoplastic material, i.e. by injection moulding., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Monica Bertoldo reports financial support was provided by DIAB Spa., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Supported Pt catalysts usually produce chlorinated byproducts during chlorinated volatile organic compounds (CVOCs) combustion, the removal of formed surface chlorine species is the key to improve the activity, selectivity and stability. In this paper, the Pt chemical state is adjusted by the interaction between Pt and CeO 2 through controlling the morphology of CeO 2 , which further affects the catalytic performance of VC combustion. For Pt/CeO 2 -octahedron, the weak interaction between Pt and CeO 2 results in the formation of PtO 2 , facilities VC adsorption and C-Cl bonds cleavage and becomes a key active site to accommodate the dissociated Cl species. While the strong interaction leads to the formation of Pt x Ce 1-x O 2-σ solid solution on Pt/CeO 2 -rod has relative lower ability in Cl species removal compared with PtO 2 . Density functional theory (DFT) calculations also confirms that the introduced Pt species reduces the concentration of Cl species on the surface as well as the chlorinated-byproducts. Hence, Pt/CeO 2 -octahedron outperformed Pt/CeO 2 -rod and Pt/CeO 2 -cube with 90% VC conversion at 280 °C. Furthermore, under the same VC conversion (90%), the concentration of chlorinated byproducts on Pt/CeO 2 -octahedron was only 4% than that of Pt/CeO 2 -rod., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Thiodiglycolic acid (TDGA) is a biomarker for monitoring vinyl chloride exposure. Exploring a facile, rapid and precise analysis technology to quantify TDGA is of great significance. In this research, we demonstrate a fluorescent sensor based on dual-emissive UiO-66 for TDGA detection. This ratiometric fluorescent material named C460@Tb-UiO-66-(COOH) 2 was designed and synthesized by introducing organic dye 7-diethylamino-4-methylcoumarin (C460) and Tb 3+ into UiO-66-(COOH) 2 . The as-obtained C460@Tb-UiO-66-(COOH) 2 samples showed highly selective recognition, excellent anti-interference and rapid response characteristics for the recognition of TDGA. The detection limit is 0.518 mg·mL -1 , which is much lower than the threshold of 20 mg·mL -1 for a healthy person. In addition, the mechanism of TDGA-induced fluorescence quenching is discussed in detail. This sensor is expected to detect TDGA content in human urine.

Chlorinated ethene (CE) contaminants are widespread in groundwater, and the occurrence of vinyl chloride (VC), among others, is a well-known issue due to its mobility, persistence, and carcinogenicity. Human exposure to VC may occur through inhalation after soil vapor intrusion into buildings at sites with shallow underground contamination. Soil vapor intrusion risk is traditionally assessed through indoor air and sub-slab sampling (direct evidence) or soil gas and groundwater surveys (indirect evidence). Phytoscreening (sampling and analysis of tree trunk matrices) was proven as a cost-effective alternative technique to indirectly detect shallow underground contamination by higher chlorinated ethenes and subsequent vapor intrusion risk. However, the technique has appeared barely capable to screen for the lower chlorinated VC, likely due to its fugacity and aerobic bio-degradability, with only one literature record to date showing successful detection in trees. We applied phytoscreening at two sites with severe CE contamination nearby residential buildings caused by illegal dumping of chlorinated pitches from petrochemical productions. The two sites show variable amounts of VC in the shallow groundwater (1e2 to 1e4 μg/L), posing potential sanitary risk issues. Former soil gas surveys did not detect VC in the vadose zone. At both sites, we sampled trunk micro-cores and trunk gas from poplar trees close to contaminated piezometers in different seasons. VC was detected in several instances, disproving the shared literature assumption of the inefficacy of phytoscreening towards this compound. Factors influencing the detectability of VC and other CEs in trees were analyzed through linear regressions. Two different conceptual models were proposed to explain the effective uptake of VC by trees at the two sites, i.e., direct uptake of contaminated groundwater at the first site and uptake of VC from an anoxic vadose zone at the second site. In planta reductive dechlorination of CEs is not expected based on current literature knowledge. Thus, the detection of VC in trunks would indicate its occurrence in the shallow underground, suggesting higher screening effectiveness of phytoscreening compared to soil gas; this has implications for indirect vapor intrusion risk assessment., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this study, thirty-four soil samples from a typical chlor-alkali slag residue storage site near the city of Qiqihar in northeastern China were collected and their arsenic, cadmium, chromium, copper, mercury, nickel, lead and zinc concentrations were determined. Sources of these heavy metals were analyzed with a positive matrix factorization model, and the health risks associated with different pollution sources were calculated. The results showed that mercury was the main heavy metal pollutant at the site (maximum concentration of 112.19 mg.kg-1) and the soil was also contaminated with arsenic, copper and lead. The sources of eight heavy metals were: mixed oil refinery wastewater and parent material (arsenic, chromium, copper and lead), vinyl chloride waste source (mercury), parent material (cadmium, nickel and zinc). The average potential ecological risk of the soil was 22344.39, with vinyl chloride waste source contributing 99.85% of this risk. The average carcinogenic risk of a mixture of oil refinery wastewater and parent material for children and adults was 9.06×10-6 and 6.36×10-6, respectively, accounting for 99.9% (children) and 99.48% (adults) of the total average carcinogenic risk. The average hazard index of vinyl chloride waste source for children and adults was 0.6 and 0.38, respectively, which accounted for 64.13% (children) and 52.34% (adults) of the total hazard index. These results provide a reference for soil pollution risk assessments at this type of site., Competing Interests: The authors have declared that no competing interests exist.

Chlorinated ethene (CE) groundwater contamination is commonly treated through anaerobic biodegradation (i.e., reductive dechlorination) either as part of an engineered system or through natural attenuation. Aerobic biodegradation has also been recognized as a potentially significant pathway for the removal of the lower CEs cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC). However, the role of aerobic biodegradation under low oxygen conditions typical of contaminated groundwater is unclear. Bacteria capable of aerobic VC biodegradation appear to be common in the environment, while aerobic biodegradation of cDCE is less common and little is known regarding the organisms responsible. In this study, we investigate the role of aerobic cDCE and VC biodegradation in a mixed contaminant plume (including CEs, BTEX, and ketones) at Naval Air Station North Island, Installation Restoration Site 9. Sediment and groundwater collected from the plume source area, mid-plume, and shoreline were used to prepare microcosms under fully aerobic (8 mg/L dissolved oxygen (DO)) and suboxic (< 1 mg/L DO) conditions. In the shoreline microcosms, VC and cDCE were rapidly degraded under suboxic conditions (100% and 77% removal in < 62 days). In the suboxic VC microcosms, biodegradation was associated with a > 5 order of magnitude increase in the abundance of functional gene etnE, part of the aerobic VC utilization pathway. VC and cDCE were degraded more slowly under fully aerobic conditions (74% and 30% removal) in 110 days. High-throughput 16S rRNA and etnE sequencing suggest the presence of novel VC- and cDCE-degrading bacteria. These results suggest that natural aerobic biodegradation of cDCE and VC is occurring at the site and provide new evidence that low (< 1 mg/L) DO levels play a significant role in natural attenuation of cDCE and VC., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)