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Per- and polyfluoroalkyl substances (PFASs) from aqueous film forming foams (AFFFs) can hinder bioremediation of co-contaminants such as trichloroethene (TCE) and benzene, toluene, ethylbenzene, and xylene (BTEX). Anaerobic dechlorination can require bioaugmentation of Dehalococcoides, and for BTEX, oxygen is often sparged to stimulate in situ aerobic biodegradation. We tested PFAS inhibition to TCE and BTEX bioremediation by exposing an anaerobic TCE-dechlorinating coculture, an aerobic BTEX-degrading enrichment culture, and an anaerobic toluene-degrading enrichment culture to n-dimethyl perfluorohexane sulfonamido amine (AmPr-FHxSA), perfluorohexane sulfonamide (FHxSA), perfluorohexanesulfonic acid (PFHxS), or nonfluorinated surfactant sodium dodecyl sulfate (SDS). The anaerobic TCE-dechlorinating coculture was resistant to individual PFAS exposures but was inhibited by >1000× diluted AFFF. FHxSA and AmPr-FHxSA inhibited the aerobic BTEX-degrading enrichment. The anaerobic toluene-degrading enrichment was not inhibited by AFFF or individual PFASs. Increases in amino acids in the anaerobic TCE-dechlorinating coculture compared to the control indicated stress response, whereas the BTEX culture exhibited lower concentrations of all amino acids upon exposure to most surfactants (both fluorinated and nonfluorinated) compared to the control. These data suggest the main mechanisms of microbial toxicity are related to interactions with cell membrane synthesis as well as protein stress signaling.

Trichloroethylene (TCE) is a prevalent groundwater contaminant detected worldwide, and microbes are sensitive indicators and initial responders to these chemical contaminants causing disturbances to their ecosystem. In this study, microbes isolated from San Marcos River sediment were screened for their TCE degradation potential. Among the twelve isolates (SAN1-12), five isolates demonstrated TCE degradation within 5 days at 25 °C and 40 mg/L of TCE concentration in the following order: SAN8 (87.56%), SAN1 (77.31%), SAN2 (76.58%), SAN3 (49.20%), and SAN7 (3.36%). On increasing the TCE concentration to 80 mg/L, the degradation efficiency of these isolates declined, although SAN8 remained the prominent TCE degrader with 75.67% degradation. The prominent TCE-degrading isolates were identified as Aeromonas sp. SAN1, Bacillus sp. SAN2, Gordonia sp. SAN3, and Bacillus proteolyticus SAN8 using 16S rRNA sequencing. The TCE degradation and cell biomass of Bacillus proteolyticus SAN8 were significantly improved when the incubation temperature was increased from 25 °C to 30 °C. However, both slightly acidic and alkaline pH levels, as well as higher TCE concentrations, lowered the efficacy of TCE degradation. Nevertheless, these conditions led to an increase in bacterial cell biomass. [ABSTRACT FROM AUTHOR]

Background: We recently reported an increased risk of Parkinson's disease (PD) in service members who resided at Marine Base Camp Lejeune, North Carolina, when water supplies were contaminated with trichloroethylene and other volatile organic compounds (VOCs). Prior studies suggest that environmental exposures may affect PD phenotype or progression, but this has not been reported for VOCs. Objective: The objective of this study was to test whether PD progression is faster in individuals exposed to VOCs in water at Camp Lejeune. Methods: A cohort of 172,128 marines residing at Camp Lejeune between 1975 and 1985 was previously assembled. We identified individuals with PD in Veterans Health Administration and Medicare databases between 2000 and 2021. Using estimates derived by the US Agency for Toxic Substances and Disease Registry, we classified individuals as exposed or unexposed to VOCs in residential water. We used Kaplan–Meier and Cox regression models to test differences between exposed and unexposed groups in the time from PD diagnosis until psychosis, fracture, fall, or death. Results: Among 270 persons with PD, 177 (65.6%) were exposed to VOCs in residential water. Median cumulative exposure was 4970 μg/L‐months, >50‐fold the permissible level. Time until psychosis, fracture, and fall were all shorter in the exposed group, with adjusted hazard ratios (HRs) exceeding 2: psychosis HR, 2.19 (95% confidence interval [CI]: 0.99–4.83); fracture HR, 2.44 (95% CI: 0.91–6.55); and fall HR, 2.64 (95% CI: 0.97–7.21). A significant dose response was observed for time to fall (P trend, 0.032). No differences were observed for time until death. Conclusions: PD progression may be faster in persons exposed to trichloroethylene and other VOCs in water decades earlier. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The coexistence of various organic pollutants in soil always draws extensive attention because of their difficulties and complexity for remediation. Especially, the impacts of bioremediation on soil co-contaminated with benzene, toluene, and trichloroethylene (TCE) have seldom been comprehensively evaluated yet. In this study, the contributions of biostimulation, bioaugmentation, and their combination for the bioremediation of the co-contaminated soil containing benzene, toluene, and TCE were systematically investigated. The addition of nutrients ((NH4)2SO4 (as N source), K2HPO4 (as P source), vegetable oil and CH3COONa (as C sources)) enhanced the degradation efficiency of the co-contaminated soil by 10.19% to 49.62%. The optimal biostimulation condition involved using vegetable oil as the carbon source with a C: N: P ratio of 100: 10: 1. Meanwhile, the addition of the microbial cultures screened and domesticated from the co-contaminated soil, named B-T, effectively enhanced the removal rate of contaminants by 33.02% to 37.55%. The genera comprising Pseudomonas, Stenotrophomonas, and Chryseobacterium in B-T exhibited the highest relative abundance, suggesting their potential for the removal of benzene, toluene, and TCE. Besides, the coupling of biostimulation and bioaugmentation enhanced the degradation efficiency by 62.38% to 68.84%, showing the most effective biodegradation effects. The coupled strategy showed synergistic effects of both, increasing the quantity and activity of microorganisms and accelerating the biodegradation of target contaminants. The findings indicated that the coupling of bioaugmentation and biostimulation treatment strategy holds promise for the bioremediation of benzene, toluene, and TCE from co-contaminated soil. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) degradation in aqueous solution containing Tween-80 (TW-80) was carried out using iron scraps (IS) coupled with citric acid (CA) to enhance Fe(II)-activated sodium persulfate (PS) system. The effects of IS synergized with CA on the enhancement of PS/Fe(II) system were explored, and the influences of chemical dosage, TW-80 concentration, initial solution pH, and inorganic anions on TCE degradation (with TW-80) were investigated. The main reactive oxygen species responsible for TCE degradation were confirmed. The results showed that IS synergized with CA can effectively enhance the TCE removal, and when the initial concentrations of TCE and TW-80 were 0.15 mmol/L and 1.0 g/L, respectively, TCE degradation reached 92.4% with the dosages of 4.5 mmol/L, 0.6 mmol/L, and 2.5 g/L of PS, Fe(II)-CA, and IS, respectively. The presence of TW-80 inhibited the TCE degradation, and the higher its concentration, the stronger the inhibition. Free radical scavenging tests and electron paramagnetic resonance analysis showed that both HO· and ... played important roles in TCE degradation with ... more important than ... In PS/Fe(II)/CA/IS system, a desired TCE removal performance was obtained at the initial solution pH<9. The presence of Cl- in the solution did not have a significant effect on TCE degradation, while the inhibition caused by ... was obvious. TCE removal was inhibited in the simulated actual groundwater experiment due to the complex solution matriexs, and the adverse effect can be overcome by increasing the chemical dosage, thus achieving higher TCE removal efficiency. [ABSTRACT FROM AUTHOR]

The decomposition efficiency of C2HCl3 and CHCl3 in a barrier discharge is very different, even though these compounds differ little in chemical composition. In both compounds, there are three chlorine atoms and one hydrogen atom. The difference between them is the presence of one carbon atom in CHCl3 and two carbon atoms connected by a double bond in C2HCl3 and the higher polarizability of C2HCl3. The polarizability of C2HCl3 is 10.21 Å3 and that of CHCl3 is 8.39 Å3. As a result of these differences, the C2HCl3 conversion was two to three times higher than the CHCl3 conversion. The main product of CHCl3 decomposition containing chlorine was ClO2, while Cl2, COCl2, HCl, CCl4, and Cl− were formed in smaller amounts. The main products of C2HCl3 decomposition, which contain chlorine, were COCl2, HCl, and Cl−. CCl4 was not formed. Cl2 and ClO2 were formed in smaller amounts. Pathways of C2HCl3 and CHCl3 decomposition are shown in this paper. The process was carried out at low power (0.2–0.8 W) in air. The gas flow was 10 L/h, and the concentration of the decomposed compound was 0.4%. The volume of the gas space of the reactor (plasma zone) was 27 cm3. [ABSTRACT FROM AUTHOR]

Objective Soil-air partitioning is a critical process influencing the environmental fate of volatile organic pollutants and a significant contributor to the risk of respiratory exposure. Methods Four typical soils-loess, red soil, black soil and sand were used to identify the soil factors affecting the partitioning of trichloroethylene. The partitioning behaviour of trichloroethylene at the soil-atmosphere interface was quantitatively investigated by single-factor controlled batch experiments, and the quantitative relationship between the trichloroethylene soil gas partition coefficient and soil factors was determined. Results The results showed significant differences in the soil-gas partition coefficients of the four typical soils (black soil>red soil>sandy soil>loess soil). The main influencing factors for the partition coefficient of black soil were primarily particle size, water content, and organic matter content. Whereas, for the other three soils, the main factors were particle size and water content. Conclusion The relationships between the soil gas partition coefficient of TCE and soil factors in black soil can be quantitatively expressed as follows: KSA=-0.744X1-0.224X2+0.704X3; sand: KSA=-0.724X1-0.222X2; loess: KSA=-0.291X1-0.268X2; and red soil: KSA=-0.589X1-0.338X2 (X1: water content; X2: particle size; X3: organic matter content). These research aids in a deeper understanding of the distribution behaviour of trichloroethylene at the soil-atmosphere interface in typical soils in China and the influence of soil factors and provide a theoretical basis for the quantification of multifactor coupling effects and health risk assessment in the process of soil gas partitioning.

The decomposition efficiency of C2HCl3 and CHCl3 in a barrier discharge is very different, even though these compounds differ little in chemical composition. In both compounds, there are three chlorine atoms and one hydrogen atom. The difference between them is the presence of one carbon atom in CHCl3 and two carbon atoms connected by a double bond in C2HCl3 and the higher polarizability of C2HCl3. The polarizability of C2HCl3 is 10.21 Å3 and that of CHCl3 is 8.39 Å3. As a result of these differences, the C2HCl3 conversion was two to three times higher than the CHCl3 conversion. The main product of CHCl3 decomposition containing chlorine was ClO2, while Cl2, COCl2, HCl, CCl4, and Cl− were formed in smaller amounts. The main products of C2HCl3 decomposition, which contain chlorine, were COCl2, HCl, and Cl−. CCl4 was not formed. Cl2 and ClO2 were formed in smaller amounts. Pathways of C2HCl3 and CHCl3 decomposition are shown in this paper. The process was carried out at low power (0.2–0.8 W) in air. The gas flow was 10 L/h, and the concentration of the decomposed compound was 0.4%. The volume of the gas space of the reactor (plasma zone) was 27 cm3.

Interactions and nutrient exchanges among members of microbial communities are important for understanding functional relationships in environmental microbiology. We can begin to elucidate the nature of these complex systems by taking a bottom-up approach utilizing simplified, but representative, community members. Here, we assess the effects of a toxic stress event, the addition of arsenite (As(III)), on a syntrophic co-culture containing lactate-fermenting Desulfovibrio vulgaris Hildenborough and solvent-dechlorinating Dehalococcoides mccartyi strain 195. Arsenic and trichloroethene (TCE) are two highly prevalent groundwater contaminants in the United States, and the presence of bioavailable arsenic is of particular concern at remediation sites in which reductive dechlorination has been employed. While we previously showed that low concentrations of arsenite (As(III)) inhibit the keystone TCE-reducing microorganism, D. mccartyi, this study reports the utilization of physiological analysis, transcriptomics, and metabolomics to assess the effects of arsenic on the metabolisms, gene expression, and nutrient exchanges in the described co-culture. It was found that the presence of D. vulgaris ameliorated arsenic stress on D. mccartyi, improving TCE dechlorination under arsenic-contaminated conditions. Nutrient and amino acid export by D. vulgaris may be a stress-ameliorating exchange in this syntrophic co-culture under arsenic stress, based on upregulation of transporters and increased extracellular nutrients like sarcosine and ornithine. These results broaden our knowledge of microbial community interactions and will support the further development and implementation of robust bioremediation strategies at multi-contaminant sites.

OBJECTIVES: Etiological factors of testicular germ cell tumors (TGCT) remain largely unknown, but a causal role of occupational exposures to solvents has been suggested. Previous studies analyzing these exposures reported discordant results, potentially related to exposure assessment methods. The aim of this study was to investigate the role of occupational exposure to solvents on the risk of developing TGCT among young men. METHODS: This study examined occupational exposures to solvents and TGCT risk based on the lifetime work histories of 454 cases and 670 controls, aged 18–45 years, of the French national TESTIS case–control study. Solvent exposure was estimated using: (i) exposure assignment by job-exposure matrix (JEM) and (ii) JEM combined with self-reported exposure data from specific questionnaires (SQ) and expert assessment (EA). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression models. RESULTS: Both approaches (JEM and JEM+SQ+EA) showed a consistent association between TGCT and trichloroethylene exposure (exposed versus not exposed; JEM=OR 1.80 [95% confidence interval (CI) 1.12–2.90] and JEM+SQ+EA= OR 2.59 (95% CI 1.42–4.72). Both approaches also observed positive associations with ketone esters and fuels & petroleum-based solvents. CONCLUSION: The results suggest that some organic solvents might be involved in the pathogenesis of TGCT among occupationally exposed men. The combined use of JEM+SQ+EA seemed to limit misclassification by considering individual exposure variability and is, therefore, an appealing approach to assess occupational exposures in epidemiological studies.

Objective To establish an automated headspace -gas chromatography method for the determination of 1,1,2,2 - tetrachloroethene in human urine. Methods A urine sample of 5.00 mL was placed in a 20 mL headspace vial, and 2.0 g of anhydrous sodium sulfite was added before sealing the vial. The vial was placed in an automated headspace sampler and heated at 80 ℃ for 50.00 min to equilibrate. Under these heating conditions, 1,1,2,2 -tetrachloroethene in human urine was completely reacted with anhydrous sodium sulfite to form trichloroethylene. The trichloroethylene vapor above the headspace vial was separated by a DB-624 capillary column and detected with a flame ionization detector. Quantification was achieved by plotting a standard curve with the peak area of trichloroethylene and the mass concentration of 1,1,2,2- tetrachloroethane. Results The results showed good linear ranges of 1,1,2,2 -tetrachloroethene in urine between 0.008 3 and 32.000 mg/L, and the correlation coefficient was higher than 0.999 4. For this method, the limit of detection was 2.5 μg/L, and the lower limit of quantification was 8.3 μg/L; the intra-batch precision was 4.79% to 5.28%, and the interbatch precision was 4.61% to 6.44% ; the average recovery rate was 87.53% to 101.17% . Conclusions The automated headspace gas chromatography method for determining 1,1,2,2-tetrachloroethene in human urine was characterized by high sensitivity, good linearity, minimal interference, high precision, and simple sample preparation. It is suitable for measuring the concentration of 1,1,2,2-tetrachloroethene in human urine. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is a commonly used organic solvent in industry. Our previous studies have found that TCE can cause liver injury accompanied by macrophage polarization, but the specific mechanism is unclear. The epigenetic regulation of macrophage polarization is mainly focused on histone modification. Histone lysine demethylase 4A (KDM4A) is involved in the activation of macrophages. In this study, we used a mouse model we investigated the role of KDM4A in the livers of TCE‐drinking mice and found that the expression of KDM4A, M1‐type polarization indicators, and related inflammatory factors in the livers of TCE‐drinking mice. In the study, BALB/c mice were randomly divided into four groups: 2.5 mg/mL TCE dose group and 5.0 mg/mL TCE dose group, the vehicle control group, and the blank control group. We found that TCE triggered M1 polarization of mouse macrophages, characterized by the expression of CD11c and robust production of inflammatory cytokines. Notably, exposure to TCE resulted in markedly increased expression of KDM4A in macrophages. Functionally, the increased expression of KDM4A significantly impaired the expression of H3K9me3 and H3K9me2 and increased the expression of H3K9me1. In addition, KDM4A potentially represents a novel epigenetic modulator, with its upregulation connected to β‐catenin activation, a signal critical for the pro‐inflammatory activation of macrophages. Furthermore, KDM4A inhibitor JIB‐04 treatment resulted in a decrease in β‐catenin expression and prevented TCE‐induced M1 polarization and the expression of the pro‐inflammatory cytokines TNF‐α and IL‐1β. These results suggest that the association of KDM4A and Wnt/β‐catenin cooperatively establishes the activation and polarization of macrophages and global changes in H3K9me3/me2/me1. Our findings identify KDM4A as an essential regulator of the polarization of macrophages and the expression of inflammatory cytokines, which might serve as a potential target for preventing and treating liver injury caused by TCE. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Sulfonamide antibiotics (SAs) are widely used antimicrobial agents in livestock and aquaculture, and most of them entering the animal's body will be released into the environment as prodrugs or metabolites, which ultimately affect human health through the food chain. Both acid deposition and salinization of soil may have an impact on the migration and degradation of antibiotics. Sulfamethazine (SM2), a frequently detected compound in agricultural soils, has a migration and transformation process in the environment that is closely dependent on environmental pH. Nevertheless, scarcely any studies have been conducted on the effect of soil pH changes on the environmental behavior of sulfamethazine. We analyzed the migration and degradation mechanisms of SM2 using simulation experiments and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) techniques. The results showed that acidic conditions limited the vertical migration of sulfadimidine, and SM2 underwent different reaction processes under different pH conditions, including S-C bond breaking, S-N bond hydrolysis, demethylation, six-membered heterocyclic addition, methyl hydroxylation and ring opening. The study of the migration pattern and degradation mechanism of SM2 under different pH conditions can provide a solid theoretical basis for assessing the pollution risk of sulfamethazine degradation products under acid rain and saline conditions, and provide a guideline for remediation of antibiotic contamination, so as to better prevent, control and protect groundwater resources. [ABSTRACT FROM AUTHOR]

In order to improve the adsorption and reduction performance of zero-valent iron nanoparticles on pollutants, the carbon-loaded zero-valent iron nanoparticles ( Fe/C) were prepared by aerosol-assisted fabrication, and the modified material (S-Fe/C) was prepared by sulfurizing and modifying Fe/C. The material characteristics were investigated by various methods, such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), etc. The material characteristics of S-Fe/C were also investigated, and the material characteristics of S-Fe/C were investigated. The adsorption properties of the material towards malachite green(MG) and the reduction properties towards trichloroethylene (TCE) were explored. The results showed that the adsorption of MG by S-Fe/C reached 1 663 mg/g and the removal rate of TCE for 10 h was 85.57%, indicating that S-Fe/C has good adsorption and reduction properties. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is an industrial solvent and widespread environmental contaminant associated with CD4+ T-cell activation and autoimmune disease. Prior studies showed that exposure to TCE in the drinking water of autoimmune-prone mice expanded effector/memory CD4+ T cells with an interferon-γ (IFN-γ)-secreting Th1-like phenotype. However, very little is known how TCE exposure skews CD4+ T cells towards this pro-inflammatory Th1 subset. As observed previously, TCE exposure was associated with hypermethylation of regions of the genome related to transcriptional repression in purified effector/memory CD4 T cells. We hypothesized that TCE modulates transcriptional and/or epigenetic programming of CD4+ T cells as they differentiate from a naive to effector phenotype. In the current study, purified naive CD4 T cells from both male and female autoimmune-prone MRL/MpJ mice were activated ex vivo and polarized towards a Th1 subset for 4 days in the presence or absence of the oxidative metabolite of TCE, trichloroacetaldehyde hydrate (TCAH) in vitro. An RNA-seq assessment and reduced representation bisulfite sequencing for DNA methylation were conducted on Th1 cells or activated, non-polarized cells. The results demonstrated TCAH's ability to regulate key genes involved in the immune response and autoimmunity, including Ifng, by altering the level of DNA methylation at the gene promoter. Intriguing sex differences were observed and for the most part, the effects were more robust in females compared to males. In conclusion, TCE via TCAH epigenetically regulates gene expression in CD4+ T cells. These results may have implications for mechanistic understanding or future therapeutics for autoimmunity. [ABSTRACT FROM AUTHOR]

Site owners, regulators, and consultants now have decades of experience with vapor intrusion (VI), but guidance for the evaluation of VI continues to vary significantly among states. For those with sites in different regulatory jurisdictions, one challenge is addressing how the requirements or expectations for VI investigation and mitigation differ from one jurisdiction to the next. The overall lack of consensus can make it difficult to manage sites in a consistent manner between jurisdictions. This paper takes into account VI guidance, petroleum hydrocarbon‐specific VI guidance, and/or media‐specific volatilization criteria found in broader regulatory programs. This is an update of the author's previous reviews published in 2007, 2012, and 2018. Since our most recent update, 30 states have revised their guidance, issued new guidance or updated criteria or other VI‐related information. For each State and the District of Columbia, the review includes tabulations of the available types of screening values (e.g., soil, groundwater, soil gas, and indoor air), the screening values for selected chemicals that commonly drive VI investigations (e.g., trichloroethylene [TCE], tetrachloroethylene [PCE], benzene, and other selected volatile organic compounds [VOCs]), and the basis of risk levels used for cancer and non‐cancer risk. Federal values are also included for comparison. In addition, we summarize available key policy criteria for each state including: trigger distances, default subsurface to indoor air attenuation factors, policies for evaluation of petroleum VI, strategies for preferential pathways, and policies for mitigation of VI. The details presented in this paper provide a useful technical reference and regulatory summary for practitioners and the regulated community nationwide. [ABSTRACT FROM AUTHOR]

Acetylene, ethene, and ethane are products from the degradation of trichloroethene (TCE) in contaminated aquifers. However, the volatility of these gases makes it challenging to avoid excessive losses during sampling. The objective of this study was to compare the quantification of acetylene, ethene, and ethane using passive vapor diffusion (PVD) samplers vs. conventional low‐flow groundwater collection. Samples were obtained from 8 to 13 monitoring wells at three sites that show potential for biotic and abiotic degradation of TCE in fractured rock aquifers. Method reporting limits (MRLs) for the PVD samplers were 0.25 μg/L for acetylene (0.0094 μM) and 0.28 μg/L for ethene and ethane (0.0099 and 0.0092 μM, respectively); the MRLs for conventional low‐flow groundwater samples were ~40% higher. For two of the sites, the maximum concentrations of acetylene, ethene, and ethane obtained with the PVD samplers were comparable to the conventional low‐flow samples. The frequency of detection for these gases with the PVD samplers was also comparable to conventional low‐flow groundwater sampling. For one of the sites with higher levels of acetylene (maximum of 13 μg/L), the concentrations from the PVD samplers were approximately twofold higher than those with conventional low‐flow groundwater sampling. Based on robust detection of acetylene, ethene, and/or ethane, it appears likely that degradation of TCE is occurring at the three sites that were sampled. The use of PVD samplers can reduce the possibility of false negative results to provide another line of evidence in support of natural attenuation. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is a common environmental contaminant that can induce occupational dermatitis medicamentosa-like TCE (ODMLT), where the liver damage is the most common complication. The study aims to uncover the underlying mechanism of TCE-sensitization-induced liver damage by targeting specific exosomal microRNAs (miRNAs). Among the enriched serum exosomal miRNAs of ODMLT patients, miR-205–5p had a significant correlation coefficient with the liver function damage indicators. Moreover, retinoic acid receptor-related orphan receptor α (RORα) was identified as a direct target of miR-205–5p via specific binding. Further experiments showed that kupffer cells (KCs) underwent M1 phenotypic and functional changes in liver injury induced by TCE which were alleviated by reducing the expression of miR-205–5p. However, this alleviation was reversed by the RORα antagonist SR1001. In vitro experiments showed that miR-205–5p promoted M1 polarization of macrophages and enhanced the secretion of inflammatory factors by regulating RORα. An increase in RORα reversed the polarization direction of M1-type macrophages and reduced the secretion of proinflammatory factors. In addition, pretreatment of mice with SR1078, a specific RORα agonist, effectively blocked M1 polarization of KCs and reduced the severity of TCE-induced liver injury. Our study uncovers that miR-205–5p regulates KC M1 polarization by targeting RORα in immune liver injury induced by TCE sensitization, providing new insight into the molecular mechanisms and new therapeutic targets for ODMLT.

A systematic review and meta-analysis were conducted, aiming to establish a scientifically grounded understanding of trichloroethylene (TCE)-induced hepatotoxicity. Relevant studies published prior to February 29, 2024 were meticulously searched. The standardized mean difference (SMD) was employed to assess the correlation between the control group and the TCE exposure group, while heterogeneity was quantified using the I2 index. After a thorough screening and exclusion process, a total of 57 articles met the eligibility criteria. Important parameters pertaining to liver health, such as ALT, AST, TNF-α, IL-1β, and others, were analyzed, resulting in the identification of 40 parameters related to liver injury. The results revealed that GLB, ALP, CYP2E1, GR, IL-6 (mRNA), and TGF-β (mRNA) did not exhibit statistically significant differences (P > 0.05). However, high heterogeneity was observed in indicators other than F4/80, EGR1 (mRNA), and MDA-protein adducts (P 50%). Notably, TCE exposure significantly increased the activity of ALT, AST, LDH, as well as the expression levels of TNF-α, IL-1β, TNFR1, IL-6, P65, P-P65, F4/80, IFN-γ, iNOS, C3a, TNF-α (mRNA), IL-1β (mRNA), IL-6R (mRNA), GP130 (mRNA), EGR1 (mRNA), CCL2 (mRNA), CCL5 (mRNA), iNOS (mRNA), liver coefficient, MDA, anti-dsDNA, MDA protein adduct, anti-MDA protein adduct antibody, and ANA. Conversely, TCE exposure decreased the activities of CAT, GPx, SOD, as well as the expression levels of Nrf2, TP, ALB, and GSH. Additionally, this study provided a comprehensive review of the two mechanisms underlying liver injury following TCE exposure. In conclusion, our findings furnish compelling evidence that TCE exposure induces liver injury, as manifested by alterations in various physiological indicators, including cytokines and oxidative stress-related markers, among others.

The etiologies of Parkinson's disease (PD) remain unclear. Some, such as certain genetic mutations and head trauma, are widely known or easily identified. However, these causes or risk factors do not account for the majority of cases. Other, less visible factors must be at play. Among these is a widely used industrial solvent and common environmental contaminant little recognized for its likely role in PD: trichloroethylene (TCE). TCE is a simple, six-atom molecule that can decaffeinate coffee, degrease metal parts, and dry clean clothes. The colorless chemical was first linked to parkinsonism in 1969. Since then, four case studies involving eight individuals have linked occupational exposure to TCE to PD. In addition, a small epidemiological study found that occupational or hobby exposure to the solvent was associated with a 500% increased risk of developing PD. In multiple animal studies, the chemical reproduces the pathological features of PD.Exposure is not confined to those who work with the chemical. TCE pollutes outdoor air, taints groundwater, and contaminates indoor air. The molecule, like radon, evaporates from underlying soil and groundwater and enters homes, workplaces, or schools, often undetected. Despite widespread contamination and increasing industrial, commercial, and military use, clinical investigations of TCE and PD have been limited. Here, through a literature review and seven illustrative cases, we postulate that this ubiquitous chemical is contributing to the global rise of PD and that TCE is one of its invisible and highly preventable causes. Further research is now necessary to examine this hypothesis.

Background Industrial facilities are not located uniformly across communities in the United States, but how the burden of exposure to carcinogenic air emissions may vary across population characteristics is unclear. We evaluated differences in carcinogenic industrial pollution among major sociodemographic groups in the United States and Puerto Rico. Methods We evaluated cross-sectional associations of population characteristics including race and ethnicity, educational attainment, and poverty at the census tract level with point-source industrial emissions of 21 known human carcinogens using regulatory data from the US Environmental Protection Agency. Odds ratios and 95% confidence intervals comparing the highest emissions (tertile or quintile) to the referent group (zero emissions [ie, nonexposed]) for all sociodemographic characteristics were estimated using multinomial, population density–adjusted logistic regression models. Results In 2018, approximately 7.4 million people lived in census tracts with nearly 12 million pounds of carcinogenic air releases. The odds of tracts having the greatest burden of benzene, 1,3-butadiene, ethylene oxide, formaldehyde, trichloroethylene, and nickel emissions compared with nonexposed were 10%-20% higher for African American populations, whereas White populations were up to 18% less likely to live in tracts with the highest emissions. Among Hispanic and Latino populations, odds were 16%-21% higher for benzene, 1,3-butadiene, and ethylene oxide. Populations experiencing poverty or with less than high school education were associated with up to 51% higher burden, irrespective of race and ethnicity. Conclusions Carcinogenic industrial emissions disproportionately impact African American and Hispanic and Latino populations and people with limited education or experiencing poverty thus representing a source of pollution that may contribute to observed cancer disparities. [ABSTRACT FROM AUTHOR]

The present project studies the preparation of CuS/CuO on decoration of graphene oxide (GO) via the chemical rout as a photocatalyst to removal of trichloroethylene from the gas phase. The prepared nanocomposites was characterized using various techniques such as FESEM, EDS, XRD, FTIR, XPS, PL, UV-vis, EIS and BET analyses. FESEM images confirmed the decoration of CuS/CuO on the GO surface in the nanocomposite. BET analysis revealed that the best specific surface area of CuS/CuO on GO (1:1) about 80 m2/g. Under optimal factors, the CuS/CuO on GO (1:1) attain to rapid TCE removal rate about 98.0% under UV irradiation. The optimal factors for photo-degradation of TCE by using the CuS/CuO-GO-1, such as gas flow rate, relative humidity percentage, and TCE concentration were 0.3 g/L, 50% relative humidity, 50 m/L of TCE. The toxicity of CuS/CuO-GO nanocomposites was investigated using Escherichia coli as a model organism. The results showed that the lowest concentration of CuS/CuO-GO nanocomposites has no toxicity under UV light irradiation. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) poses a potentially toxic threat to humans and the environment and widely exists in contaminated sites. White rot fungi effectively degrade refractory pollutants, while a few research studies use white rot fungi to degrade TCE. In this study, we investigated TCE biodegradation by white rot fungi and the potential influencing factors in the environment and attempted to research the effect of TCE on the physiological characteristics of white rot fungi. White rot fungi (Trametes versicolor, Pseudotrametes gibbosa, Pycnoporus sanguines and Pleurotus ostreatus) were added to the liquid medium for shock culture. The results revealed that T. versicolor exhibited the most pronounced efficacy in removing TCE, with a degradation rate of 81.10% within a 7 d period. TCE induces and is degraded by cytochrome P450 enzymes. High pH and Cr(VI) adversely affected the effectiveness of the biodegradation of TCE, but the salinity range of 0–1% had less effect on biodegradation. Overall, the effectiveness of degradation of TCE by T. versicolor has been demonstrated, and it provides a reference for the application prospects of white rot fungi in TCE-contaminated soils. [ABSTRACT FROM AUTHOR]

AbstractAimMaterial and MethodsResultsConclusionThe current investigation’s goals are to pharmacologically evaluate the neurotherapeutic role of the bioactive compound Alpha Pinene (ALP)-loaded Self-emulsifying nano-formulation (SENF) in neurotoxin (Rotenone and the Industrial Solvent Trichloroethylene)- induced dopaminergic loss. It is believed that these models simulate important aspects of the molecular pathogenesis of Parkinson’s disease.The ALP-nano-formulation’s anti-Parkinson’s activity was compared to ALP suspension in Wistar rats after rotenone and trichloro ethylene-induced dopaminergic loss. Neurobehavioral and motor performances were measured on the 14th, 21st, and 28th day in the rotenone model. However, in the trichloroethylene model, it was measured from the 4th to the 8th week.Significant neurobehavioral improvement has been found in ALP-SENF treated animals then untreated and animals treated with plain ALP suspension. Furthermore, biochemical tests reveal marked expression of catalase, glutathione, and superoxide dismutase, which significantly combat the (Oxidative stress) OS-induced neurodegeneration.The antioxidant effect of ALP-SENF likely includes free radicals neutralization and the activation of enzymes associated with antioxidant activity, leading to the enhancement of neurobehavioral abnormalities caused by rotenone and trichloroethylene. [ABSTRACT FROM AUTHOR]

The brain- and body-first models of Lewy body disorders predict that aggregated alpha-synuclein pathology usually begins in either the olfactory system or the enteric nervous system. In both scenarios the pathology seems to arise in structures that are closely connected to the outside world. Environmental toxicants, including certain pesticides, industrial chemicals, and air pollution are therefore plausible trigger mechanisms for Parkinson's disease and dementia with Lewy bodies. Here, we propose that toxicants inhaled through the nose can lead to pathological changes in alpha-synuclein in the olfactory system that subsequently spread and give rise to a brain-first subtype of Lewy body disease. Similarly, ingested toxicants can pass through the gut and cause alpha-synuclein pathology that then extends via parasympathetic and sympathetic pathways to ultimately produce a body-first subtype. The resulting spread can be tracked by the development of symptoms, clinical assessments, in vivo imaging, and ultimately pathological examination. The integration of environmental exposures into the brain-first and body-first models generates testable hypotheses, including on the prevalence of the clinical conditions, their future incidence, imaging patterns, and pathological signatures. The proposed link, though, has limitations and leaves many questions unanswered, such as the role of the skin, the influence of the microbiome, and the effects of ongoing exposures. Despite these limitations, the interaction of exogenous factors with the nose and the gut may explain many of the mysteries of Parkinson's disease and open the door toward the ultimate goal –prevention. [ABSTRACT FROM AUTHOR]

Parkinson's disease is the world's fastest growing brain disorder, and exposure to environmental toxicants is the principal reason. In this paper, we consider alternative, but unsatisfactory, explanations for its rise, including improved diagnostic skills, aging populations, and genetic causes. We then detail three environmental toxicants that are likely among the main causes of Parkinson's disease— certain pesticides, the solvent trichloroethylene, and air pollution. All three environmental toxicants are ubiquitous, many affect mitochondrial functioning, and all can access humans via various routes, including inhalation and ingestion. We reach the hopeful conclusion that most of Parkinson's disease is thus preventable and that we can help to create a world where Parkinson's disease is increasingly rare. [ABSTRACT FROM AUTHOR]

The extraction and recovery of bitumens from bituminous mixtures is an important procedure in the paving industry. This work achieves to evaluate the rheological, permanent deformation and fatigue tests to calibration of the recovery procedure in the rotary evaporator. The protocol was divided in bitumens of known properties with laboratory aging and bitumens of unknown properties subjected to field aging. The materials were subjected to different distillation times and tested chemically, rheologically and for damage by fatigue and permanent deformation. The results indicated that the chemical FTIR test was not sensitive in capturing the presence of residual solvent in the bituminous materials due to low concentrations after recovery. The joint analysis of the |G*|, Jnr at 3.2 kPa of the MSCR and the Nf of the LAS test were consistent for determining the distillation times in the rotary evaporator to result in the absence of residual solvent and additional aging. [ABSTRACT FROM AUTHOR]

This paper describes a geostatistical approach to model and visualize the space–time distribution of groundwater contaminants. It is illustrated using data from one of the world's largest plume of trichloroethylene (TCE) contamination, extending over 23 km2, which has polluted drinking water wells in northern Michigan. A total of 613 TCE concentrations were recorded at 36 wells between May 2003 and October 2018. To account for the non-stationarity of the spatial covariance, the data were first projected in a new space using multidimensional scaling. During this spatial deformation the domain is stretched in regions of relatively lower spatial correlation (i.e., higher spatial dispersion), while being contracted in regions of higher spatial correlation. The range of temporal autocorrelation is 43 months, while the spatial range is 11 km. The sample semivariogram was fitted using three different types of non-separable space–time models, and their prediction performance was compared using cross-validation. The sum-metric and product-sum semivariogram models performed equally well, with a mean absolute error of prediction corresponding to 23% of the mean TCE concentration. The observations were then interpolated every 6 months to the nodes of a 150 m spacing grid covering the study area and results were visualized using a three-dimensional space–time cube. This display highlights how TCE concentrations increased over time in the northern part of the study area, as the plume is flowing to the so-called Chain of Lakes. [ABSTRACT FROM AUTHOR]

The CuCr mixed oxides catalysts supported on ZSM-5 zeolite (CuCr/ZSM-5) were synthesized via metal organic chemical vapour deposition (MOCVD) method for catalytic oxidation of trichloroethylene (TCE). SEM, XRD, BET, H2-TPR, NH3-TPD and XPS were tested. The active components were dispersed uniformly over the surface of ZSM-5 zeolite. The catalytic experimental results exhibited that the CuCr/ZSM-5 exhibited the best catalytic performance for TCE oxidation with 90% of TCE at 338°C and the concentration of C2Cl4 decreased compared with Cu/ZSM-5 and Cr/ZSM-5. The possible reason is that CuCr/ZSM-5 has superior reducibility, higher Cu2+ surface concentration as well as more surface oxygen. [ABSTRACT FROM AUTHOR]

Background: Environmental exposure to trichloroethylene (TCE), a carcinogenic dry‐cleaning chemical, may be linked to Parkinson's disease (PD). Objective: The objective of this study was to determine whether PD and cancer were elevated among attorneys who worked near a contaminated site. Methods: We surveyed and evaluated attorneys with possible exposure and assessed a comparison group. Results: Seventy‐nine of 82 attorneys (96.3%; mean [SD] age: 69.5 [11.4] years; 89.9% men) completed at least one phase of the study. For comparison, 75 lawyers (64.9 [10.2] years; 65.3% men) underwent clinical evaluations. Four (5.1%) of them who worked near the polluted site reported PD, more than expected based on age and sex (1.7%; P = 0.01) but not significantly higher than the comparison group (n = 1 [1.3%]; P = 0.37). Fifteen (19.0%), compared to four in the comparison group (5.3%; P = 0.049), had a TCE‐related cancer. Conclusions: In a retrospective study, diagnoses of PD and TCE‐related cancers appeared to be elevated among attorneys who worked next to a contaminated dry‐cleaning site. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Combined pulmonary fibrosis and emphysema (CPFE) is a clinical syndrome of upper-zone–predominant emphysema on high-resolution CT and a peripheral and basal–predominant diffuse pulmonary fibrosis. Multiple occupational and inhalational exposures have been associated with CPFE. We describe a U.S. veteran, who developed CPFE after a prolonged, intense exposure to trichloroethylene as an aircraft maintenance worker. We believe that this may be another example of occupational-associated CPFE. [ABSTRACT FROM AUTHOR]

Trichloroethylene-induced hypersensitivity dermatitis (TIHD) is a delayed hypersensitivity response that is affected by genetic and environmental factors. Occupational exposure to trichloroethylene (TCE) enhances antigen presentation, leading to hypersensitivity in workers with the HLA-B* 13:01 allele. Several studies have observed the activation of herpesviruses, such as Epstein Barr virus (EBV), in TIHD patients. However, the underlying mechanisms remain unclear. Toll-like receptors (TLRs) play a pivotal role in the pathogenesis of herpesvirus infection. This study aimed to explore whether TLRs serve as a shared mechanism for both herpesvirus and allergenic chemicals. In this study, HLA-B* 13:01-transfected Hmy2. A C1R cell model was constructed, and cells were treated with TCOH and EBV to explore the possible mechanisms. We established a mouse model of dermatitis and used a TLR4 agonist to verify the effect of herpesvirus on TIHD. The results showed that EBV and TCOH synergistically enhance antigen processing and presentation via the TLR2/NF-κB axis. Furthermore, TLR4 agonist further aggravated skin lesions and liver damage in TCE-sensitized mice through TLR4/NF-κB axis-mediated antigen processing and presentation. Together, this study indicates that viral infection further aggravates the inflammatory response in TIHD based on environment-gene interactions. • Trichloroethanol and EBV synergistically activated TLR2/NF-κB pathway. • Trichloroethanol and EBV promoted antigen processing and presentation. • TLR4 agonist aggravated trichloroethylene-induced antigen-presenting function. • TLR4 agonist potentiated the skin lesions of trichloroethylene-sensitized mice. [ABSTRACT FROM AUTHOR]

There is not a clear understanding of the extent by which naturally occurring reactions can attenuate trichloroethene (TCE) and its daughter products within low permeability zones (LPZs), and addressing this knowledge gap requires advancement of methods to accurately measure in situ volatile chemical concentrations. In this study, a soil coring method that freezes the soil in‐situ (a.k.a., cryogenic coring) was utilized to measure depth‐discrete distributions of TCE and its volatile reaction products through a TCE‐impacted silty clay aquitard, and results were compared with those from adjacent soil cores taken using a conventional coring approach. Vertical concentration profiles of TCE, cis‐1,2‐dichloroethylene (DCE), vinyl chloride (VC), ethane, and methane were all compared between the two coring methods, and results indicate the two coring methods recovered statistically equivalent concentrations of volatiles across most depths of the fine‐grained cohesive clayey soil at the study site. Biotic reductive dechlorination was the dominant TCE reaction pathway at the site; several reduced gasses that are possible markers for abiotic reduction were detected, but their concentrations and intervals of occurrence were not sufficiently consistent to indicate whether they were from abiotic TCE reduction or unrelated biological processes. Overall, cryogenic coring yielded improved recovery of sand lenses compared to conventional coring, but offered no apparent benefits for improved recovery of TCE and its volatile reaction products in the low permeability aquitard material at the site. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE), a widely distributed environmental chemical contaminant, is extensively dispersed throughout the environment. Individuals who are exposed to TCE may manifest occupational medicamentose-like dermatitis due to trichloroethylene (OMDT). Renal impairment typically manifests in the initial phase of OMDT and is intricately linked to the disease progression and patient outcomes. Although recombinant human tumor necrosis factor-α receptor II fusion protein (rh TNFR:Fc) has been employed in the clinical management of OMDT, there was no substantial improvement in renal function observed in patients following one week of treatment. This study primarily examined the mechanism of TNFα- and IFNγ-induced endothelial cells (ECs) PANoptosis in TCE-induced kidney injury and hypothesized that the synergistic effect of TNFα and IFNγ could be the key factor affecting the efficacy of rh TNFR:Fc therapy in OMDT patients. A TCE-sensitized mouse model was utilized in this study to investigate the effects of TNFα and IFNγ neutralizing antibodies on renal vascular endothelial cell PANoptosis. The gene of interferon regulatory factor 1 (IRF1) in human umbilical vein endothelial cells (HUVEC) was silenced by using small interfering RNA (siRNA), and the cells were then treated with TNFα and IFNγ recombinant protein to investigate the mechanism of TNFα combined with IFNγ-induced PANoptosis in HUVEC. The findings indicated that mice sensitized to TCE exhibited increased levels of PANoptosis-related markers in renal endothelial cells, and treatment with TNFα and IFNγ neutralizing antibodies resulted in a significant reduction in PANoptosis and improvement in renal function. In vitro experiments demonstrated that silencing IRF1 could reverse TNFα and IFNγ-induced PANoptosis in endothelial cells. These results suggest that the efficacy of rh TNFR:Fc may be influenced by TNFα and IFNγ-mediated PANoptosis in kidney vascular endothelial cells. The joint application of TNFα and IFNγ neutralizing antibody represented a solid alternative to existing therapeutics.

Trichloroethylene (TCE) is a prevalent groundwater contaminant detected worldwide, and microbes are sensitive indicators and initial responders to these chemical contaminants causing disturbances to their ecosystem. In this study, microbes isolated from San Marcos River sediment were screened for their TCE degradation potential. Among the twelve isolates (SAN1-12), five isolates demonstrated TCE degradation within 5 days at 25 °C and 40 mg/L of TCE concentration in the following order: SAN8 (87.56%), SAN1 (77.31%), SAN2 (76.58%), SAN3 (49.20%), and SAN7 (3.36%). On increasing the TCE concentration to 80 mg/L, the degradation efficiency of these isolates declined, although SAN8 remained the prominent TCE degrader with 75.67% degradation. The prominent TCE-degrading isolates were identified as Aeromonas sp. SAN1, Bacillus sp. SAN2, Gordonia sp. SAN3, and Bacillus proteolyticus SAN8 using 16S rRNA sequencing. The TCE degradation and cell biomass of Bacillus proteolyticus SAN8 were significantly improved when the incubation temperature was increased from 25 °C to 30 °C. However, both slightly acidic and alkaline pH levels, as well as higher TCE concentrations, lowered the efficacy of TCE degradation. Nevertheless, these conditions led to an increase in bacterial cell biomass.

Dehalococcoides mccartyi strains harboring vinyl chloride (VC) reductive dehalogenase (RDase) genes are keystone bacteria for VC detoxification in groundwater aquifers, and bioremediation monitoring regimens focus on D. mccartyi biomarkers. We isolated a novel anaerobic bacterium, Candidatus Dehalogenimonas etheniformans strain GP, capable of respiratory dechlorination of VC to ethene. This bacterium couples formate and hydrogen (H2) oxidation to the reduction of trichloro-ethene (TCE), all dichloroethene (DCE) isomers, and VC with acetate as the carbon source. Cultures that received formate and H2 consumed the two electron donors concomitantly at similar rates. A 16S rRNA gene-targeted quantitative PCR (qPCR) assay measured growth yields of (1.2 ± 0.2) × 108 and (1.9 ± 0.2) × 108 cells per μmol of VC dechlorinated in cultures with H2 or formate as electron donor, respectively. About 1.5-fold higher cell numbers were measured with qPCR targeting cerA, a single-copy gene encoding a putative VC RDase. A VC dechlorination rate of 215 ± 40 μmol L-1 day-1 was measured at 30°C, with about 25% of this activity occurring at 15°C. Increasing NaCl concentrations progressively impacted VC dechlorination rates, and dechlorination ceased at 15 g NaCl L-1. During growth with TCE, all DCE isomers were intermediates. Tetrachloroethene was not dechlorinated and inhibited dechlorination of other chlorinated ethenes. Carbon monoxide formed and accumulated as a metabolic by-product in dechlorinating cultures and impacted reductive dechlorination activity. The isolation of a new Dehalogenimonas species able to effectively dechlorinate toxic chlorinated ethenes to benign ethene expands our understanding of the reductive dechlorination process, with implications for bioremediation and environmental monitoring. IMPORTANCE Chlorinated ethenes are risk drivers at many contaminated sites, and current bioremediation efforts focus on organohalide-respiring Dehalococcoides mccartyi strains to achieve detoxification. We isolated and characterized the first non-Dehalococcoides bacterium, Candidatus Dehalogenimonas etheniformans strain GP, capable of metabolic reductive dechlorination of TCE, all DCE isomers, and VC to environmentally benign ethene. In addition to hydrogen, the new isolate utilizes formate as electron donor for reductive dechlorination, providing opportunities for more effective electron donor delivery to the contaminated subsurface. The discovery that a broader microbial diversity can achieve detoxification of toxic chlorinated ethenes in anoxic aquifers illustrates the potential of naturally occurring microbes for biotechnological applications.

1,4-dioxane is a potential carcinogen in water and is difficult to deal with due to its robust cycloether bond and complete miscibility with water. To remove 1,4-dioxane in an economically viable and environmentally friendly way, a series of carbon aerogels were synthesized as adsorbents for 1,4-dioxane. The experiment results showed that adsorption performances were closely related to the preparation conditions of carbon aerogels, such as the molar ratio, heating rate, pyrolysis temperature and residence time, which were carefully controlled. Scanning electron microscope analysis revealed the presence of a three-dimensional porous network structure in carbon aerogels. Brunauer–Emmett–Teller analysis results demonstrated an increase in specific surface area (673.89 m2/g) and total pore volume after carbonization, with an increase in mesoporous porosity and a decrease in microporosity. When considering each variable individually, the highest specific surface area of prepared carbon aerogels was achieved at a pyrolysis temperature of 800 °C, a holding time of 1 h, and a heating rate of 2 °C/min. Under optimal experimental conditions, the adsorption removal of 1,4-dioxane by carbon aerogels exceeded 95%, following quasi-second-order kinetics and Langmuir isothermal adsorption isotherms, indicating that monolayer adsorption on the surface of carbon aerogels occurred. The maximum adsorption capacity obtained was 67.28 mg/g at a temperature of 318 K, which was attributed to the presence of a large proportion of mesopores and abundant micropores simultaneously in carbon aerogels. Furthermore, with the interference of chlorinated solvents such as trichloroethylene (TCE), the removal efficiency of 1,4-dioxane had no obvious inhibition effect. Regeneration experiments showed that after five continuous cycles, the carbon aerogels still kept a comparable adsorption capacity, which illustrates its potential application in 1,4-dioxane-polluted water purification. [ABSTRACT FROM AUTHOR]

Ca2+, Mg2+, and HCO3− are extremely common coexisting ions with arsenic (As) in geogenic As-polluted groundwaters. Although extensive research has improved our knowledge of groundwater As removal techniques and mechanisms, there is still a lack of a definite explanation of the distinct influences of Ca2+ and Mg2+ on As immobilization. Furthermore, the question of whether the occurrence of metal-As aqueous complexes has positive or detrimental effects on As adsorption is still open, which hinders our ability to predict the effectiveness of groundwater As removal. The goal of our present work was to investigate the molecular-level interference mechanisms of Ca2+, Mg2+, and HCO3– on arsenic adsorption with batch/column filtration experiments and spectroscopic techniques. The results showed that the co-presence of Ca2+ and As significantly increased As(V) and As(III) adsorption by 22.1 and 12.2% in batch studies and by 20.1 and 16.7% in column adsorptive filtrations, which could be explained by forming a ternary Ca–As–TiO2 complex. Without the surface complex, Mg2+ only had a slightly positive effect on As removal. Co-existence of Ca2+ and HCO3− prevented the generation this surface complex, which significantly decreased the elimination of As(III). Inversely, the As(V) ternary complex and adsorption were not interfered by HCO3−. Moreover, an aqueous Ca–As(V) complex was detected without surface, which facilitated generation of the surface complex and As(V) adsorption. The results of this work clarified the distinct effects of Ca2+ and Mg2+ and As(V) and As(III) adsorption, which was critical in predicting the As adsorption efficiency in column filtration processes. [ABSTRACT FROM AUTHOR]

The harms caused by organic chlorides to the human body and the environment make the problem of how to degrade organic chlorides particularly urgent. Phosphides have gradually attracted attention in HDC due to their high catalytic performance. In view of the important role of O in catalytic process, the preparation of C, O co‐doped MoP was achieved by the synergistic modification of EDTA and glucose. Compared with unmodified MoP, the doping of carbon and oxygen in MoP−C−O ensure that more active sites are exposed on the surface. At the same time, the high dispersion of MoP on the carbon matrix increases the specific surface area of MoP−C−O, which is more conducive to the adsorption of reactants on the surface, thereby effectively improving the catalytic activity of the modified MoP−C−O. In the case of changing the molar ratio of MoP and surface modifier, the best activity of MoP−C−O (50 %) reaches 57.80 %, which is 2.3 times higher than that of MoP catalyst. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is one of the most pervasive environmental contaminants in the world and is associated with Parkinson disease (PD) risk. Experimental models in rodents show that TCE is selectively toxic to dopaminergic neurons at high doses of ingestion, however, TCE is a highly volatile toxicant, and the primary pathway of human exposure is inhalation. As TCE is a highly lipophilic, volatile organic compound (VOC), inhalation exposure results in rapid diffusion throughout the brain, avoiding first-pass hepatic metabolism that necessitated high doses to recapitulate exposure conditions observed in human populations. We hypothesized that inhalation of TCE would induce significantly more potent neurodegeneration than ingestion and better recapitulate environmental conditions of vapor intrusion or off gassing from liquid TCE. To this end, we developed a novel, whole-body passive exposure inhalation chamber in which we exposed 10-month-old male and female Lewis rats to 50 ppm TCE (time weighted average, TWA) or filtered room air (control) over 8 weeks. In addition, we exposed 12-month-old male and female C57Bl/6 mice to 100 ppm TCE (TWA) or control over 12 weeks. Both rats and mice exposed to chronic TCE inhalation showed significant degeneration of nigrostriatal dopaminergic neurons as well as motor and gait impairments. TCE exposure also induced accumulation of pSer129-αSyn in dopaminergic neurons as well as microglial activation within the substantia nigra of rats. Collectively, these data indicate that TCE inhalation causes highly potent dopaminergic neurodegeneration and recapitulates some of the observed neuropathology associated with PD, providing a future platform for insight into the mechanisms and environmental conditions that influence PD risk from TCE exposure. [ABSTRACT FROM AUTHOR]

Being classified as a suspected carcinogen, 1,4-dioxane (1,4-D) has been one of the most frequently detected organic contaminants in groundwater sites. Due to the common co-occurrence of 1,4-D with chlorinated compounds and a lack of comprehensive health advisory guideline standards established for potable water and other uses on a global scale, a new research emphasis to reflect more realistic situations needs to be placed onto the effects of common co-existing chemicals such as 1,1-dichloroethene, trichloroethylene, cis-1,2-dichloroethylene, and 1,1,1-trichloroethane on the environmental fate of 1,4-D. Additives (e.g., ions, nutrients, enzymes) are also introduced to enhance 1,4-D treatment efficiencies. To the best of our knowledge, however, there is no review article dealing with the removal of 1,4-D in the presence of chlorinated solvents and other interfering substances. Understanding its concurrent removal with the main chlorinated co-contaminants is necessary for more insightful and proper design of effective remediation strategies for 1,4-D. This review article will focus on the behavior, transport, and persistence of 1,4-D in the presence of other pervasive groundwater contaminants and substrates under diverse environmental conditions and treatment technologies. This review will also provide detailed information on currently available remediation technologies for 1,4-D (either individually or co-occurring) and potential key points to be considered for future technologies development. 1,4-dioxane (1,4-D) is an emerging toxic pollutant that is found as a contaminant in soil and groundwater. Despite its harmful nature, there are not many global standards regulating its levels in water. Therefore, finding effective ways to remove harmful pollutants is crucial for safer waters, requiring extended research and time. 1,4-D often exists together with other contaminants such as chlorinated solvents, making water treatment more difficult, costly, and less efficient. This review explains the physical and chemical behaviors of other co-contaminants when combined with 1,4-D as well as the current removal technologies as categorized based on physical, chemical, biological, or combination (hybrid) methods. It is found that each removal technique has its strengths and weaknesses but some failing to eliminate the co-solvents although they successfully removed 1,4-D. Thus, future research is warranted to further elucidate key reaction mechanisms between 1,4-D and other co-contaminants and to test real scale applications. [ABSTRACT FROM AUTHOR]

Advances in many isolation studies have revealed that pure Dehalococcoides grow stably, although the large‐scale pure cultivation of Dehalococcoides has yet to be established. In this study, 7 L‐culturing of Dehalococcoides mccartyi strain NIT01 was first performed using vessels made of glass and stainless alloy SUS304. All batches cultured in the glass vessel successfully dechlorinated >95% of 1 mM trichloroethene (TCE) to ethene (ETH), whereas only 5 out of 13 batches cultured in the SUS304 vessel did the same. The difference in dechlorination efficiency suggested the possible inhibition of dechlorination by SUS304. Also, the strain NIT01 showed long delays in dechlorination with pieces of SUS316, steel, and a repeatedly used SUS304, but not with titanium. The repeatedly used SUS304 cracked and increased the Fe2+ concentration to ≥76 μM. Dechlorination by this strain was also inhibited with ≥1000 μM Fe2+ and ≥23 μM Cr3+ but not with ≤100 μM Ni2+, suggesting that Cr3+ eluted from solid stainless alloys inhibited the dechlorination. Culturing in a titanium vessel instead of a stainless alloy showed the complete dechlorination of 1 mM TCE within 12–28 days with a growth yield of 2.7 × 107 cells/μmol‐released Cl−, even after repeating use of the vessels six times. [ABSTRACT FROM AUTHOR]

The applicability of high pressure rotary spray and direct pressure injection in situ remediation technologies in low permeability formations lacks a systematic theoretical analysis and practical comparison. Taking a trichloroethylene (TCE) contaminated site in Shanghai as an example, this study discusses the suitability of in situ remediation technologies in terms of agent selection, analysis of process influence radius, and remediation effectiveness. A comparative analysis between zero-valent iron (ZVI) reduction technology and persulfate (PS) activation oxidation technology demonstrates that PS activation oxidation technology is more mature and provides better remediation outcomes. The theoretical calculations of the influence radius for high pressure rotary spray and direct pressure injection technologies are conducted using the theory of circular cross-section free turbulent jets and Buckingham fluid column seepage theory, respectively. The results indicate that both technologies' influence radii are influenced by soil properties and process parameters. For instance, when the dual-pipe high pressure rotary spray drill rod has a diameter of 50 mm, nozzle diameter of 2 mm, injection pressure of 30 MPa, air pressure of 0.8 MPa, rotation speed of 10 r-min-1, and uplift speed of 25 cm-min-1, the influence diameter can exceed 0.9 m in silty clay, silty clay with silt, sandy loam, and muddy clay. The direct pressure injection technology shows significant differences in the influence radius among different soil layers. For example, at an injection pressure of 5 MPa, the time required to achieve a 1 m influence radius in sandy soil is 0.23 h, while it increases to 120.6 h in silty clay. Increasing the injection pressure to 30 MPa still requires 20.1 h to achieve a 1 m influence radius in silty clay. Based on the theoretical analysis of the influence radius, the remediation process and parameters are determined, and a pilot-scale remediation of TCE-contaminated soil is carried out using ferrous sulfate activation of PS oxidation technology. The results show a significant degradation of TCE in the soil, with residual mass fractions below the risk control values. These research e research findings can provide theoretical and empirical references for the application of high pressure rotary spray and direct pressure injection technologies in low permeability formation remediation projects. [ABSTRACT FROM AUTHOR]

In this study, carbon nanofibers were synthesized by the catalytic pyrolysis of trichloroethylene (CNF-Cl) and its mixture with acetonitrile (CNF-Cl-N). The addition of acetonitrile resulted in the incorporation of nitrogen in the CNF (0.33 at%), the removal of chlorine, an increase in oxygen-containing functional groups on the surface (from 1.6 to 3.6 at%), and an increase in the volume of mesopores (from 0.35 to 0.41 cm3·g−1) and macropores (from 0.115 to 0.393 cm3·g−1). The study of 2,4-DCBA adsorption on both CNFs revealed that the adsorption capacity showed dependence with a maximum on the 2,4-DCBA concentration in the solution, which was attributed to the electrostatic interactions of adsorbate with adsorbent at various pHs. The adsorption forces were effective over distances greater than the size of the 2,4-DCBA molecule, indicating volume pore filling. The maximum adsorption capacity occurred at 0.7–1.2 mM and a pH of 3.4 ± 0.1. CNF-Cl-N exhibited lower 2,4-DCBA adsorption than CNF-Cl-N due to its lower specific surface area, lower micropore volume, and higher concentration of oxygen-containing groups on the surface. However, these differences were not significant, suggesting that CNFs produced from both chlorine-containing wastes and their mixtures with nitrogen-containing compounds can be effectively used for water treatment to remove 2,4-DCBA. [ABSTRACT FROM AUTHOR]

In this investigation, the potential use of native β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) as encapsulating agents for trichloroethylene (TCE) was assessed. Various quantum chemical parameters, including HOMO, LUMO, and HOMO–LUMO gap, were calculated. The docking process was examined by considering different initial configurations. The complexation energies were calculated at the molecular level using DFT/BLYP-D4 and PBEh-3c calculations to gain insight into TCE encapsulation within the β-CD and HP-β-CD cavities. We used the independent gradient model (IGM) and extended charge decomposition analysis (ECDA) approaches to examine non-covalent interactions and charge transfer within TCE@β-CD and TCE@HP-β-CD complexes. The calculated thermodynamic data and complexation energies exhibited negative values for both considered complexes, indicating a favorable complexation process. Weak Van der Waals intermolecular interactions were the main driving forces in stabilizing the formed complex. Additionally, Monte Carlo simulations were conducted for a better understanding of the inclusion process. Our results provide evidence for the use of β-CD and HP-β-CD as suitable macrocyclic hosts for complexing trichloroethylene. [ABSTRACT FROM AUTHOR]

We have previously shown that excessive activation of macrophage proinflammatory activity plays a key role in TCE-induced immune liver injury, but the mechanism of polarization is unclear. Recent studies have shown that TLR9 activation plays an important regulatory role in macrophage polarization. In the present study, we demonstrated that elevated levels of oxidative stress in hepatocytes mediate the release of mtDNA into the bloodstream, leading to the activation of TLR9 in macrophages to regulate macrophage polarization. In vivo experiments revealed that pretreatment with SS-31, a mitochondria-targeting antioxidant peptide, reduced the level of oxidative stress in hepatocytes, leading to a decrease in mtDNA release. Importantly, SS-31 pretreatment inhibited TLR9 activation in macrophages, suggesting that hepatocyte mtDNA may activate TLR9 in macrophages. Further studies revealed that pharmacological inhibition of TLR9 by ODN2088 partially blocked macrophage activation, suggesting that the level of macrophage activation is dependent on TLR9 activation. In vitro experiments involving the extraction of mtDNA from TCE-sensitized mice treated with RAW264.7 cells further confirmed that hepatocyte mtDNA can activate TLR9 in mouse peritoneal macrophages, leading to macrophage polarization. In summary, our study comprehensively confirmed that TLR9 activation in macrophages is dependent on mtDNA released by elevated levels of oxidative stress in hepatocytes and that TLR9 activation in macrophages plays a key role in regulating macrophage polarization. These findings reveal the mechanism of macrophage activation in TCE-induced immune liver injury and provide new perspectives and therapeutic targets for the treatment of OMDT-induced immune liver injury.

Trichloroethylene (TCE)-induced hypersensitivity syndrome (THS) has been a concern for many researchers in the field of environmental and occupational health. Currently, there is no specific treatment for THS, leaving patients to contend with severe infections arising from extensive skin lesions, consequently leading to serious adverse effects. However, the pathogenesis of severe skin damage in THS remains unclear. This study aims to investigate the specific danger signals and mechanisms underlying skin damage in THS through in vivo and in vitro experiments. We identified that cell supernatant containing 15 kDa granulysin (GNLY), released from activated CD3-CD56+NK cells or CD3+CD56+NKT cells in PBMC induced by TCE or its metabolite, promoted apoptosis in HaCaT cells. The apoptosis level decreased upon neutralization of GNLY in the supernatant by a GNLY-neutralizing antibody in HaCaT cells. Subcutaneous injection of recombinant 15 kDa GNLY exacerbated skin damage in the THS mouse model and better mimicked patients’ disease states. Recombinant 15 kDa GNLY could directly induce cellular communication disorders, inflammation, and apoptosis in HaCaT cells. In addition to its cytotoxic effects, GNLY released from TCE-activated NK cells and NKT cells or synthesized GNLY alone could induce aberrant expression of the E3 ubiquitin ligase PDZRN3, causing dysregulation of the ubiquitination of the cell itself. Consequently, this resulted in the persistent opening of gap junctions composed of connexin43, thereby intensifying cellular inflammation and apoptosis through the “bystander effect”. This study provides experimental evidence elucidating the mechanisms of THS skin damage and offers a novel theoretical foundation for the development of effective therapies targeting severe dermatitis induced by chemicals or drugs.