Trichloroethylene Research Articles

Sulfonamide Per- and Polyfluoroalkyl Substances Can Impact Microorganisms Used in Aromatic Hydrocarbon and Trichloroethene Bioremediation.

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.

The role of PANoptosis in renal vascular endothelial cells: Implications for trichloroethylene-induced kidney injury

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.

LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants

Idiopathic Parkinson's disease (PD) is epidemiologically linked with exposure to toxicants such as pesticides and solvents, which comprise a wide array of chemicals that pollute our environment. While most are structurally distinct, a common cellular target for their toxicity is mitochondrial dysfunction, a key pathological trigger involved in the selective vulnerability of dopaminergic neurons. We and others have shown that environmental mitochondrial toxicants such as the pesticides rotenone and paraquat, and the organic solvent trichloroethylene (TCE) appear to be influenced by the protein LRRK2, a genetic risk factor for PD. As LRRK2 mediates vesicular trafficking and influences endolysosomal function, we postulated that LRRK2 kinase activity may inhibit the autophagic removal of toxicant damaged mitochondria, resulting in elevated oxidative stress. Conversely, we suspected that inhibition of LRRK2, which has been shown to be protective against dopaminergic neurodegeneration caused by mitochondrial toxicants, would reduce the intracellular production of reactive oxygen species (ROS) and prevent mitochondrial toxicity from inducing cell death. To do this, we tested in vitro if genetic or pharmacologic inhibition of LRRK2 (MLi2) protected against ROS caused by four toxicants associated with PD risk – rotenone, paraquat, TCE, and tetrachloroethylene (PERC). In parallel, we assessed if LRRK2 inhibition with MLi2 could protect against TCE-induced toxicity in vivo, in a follow up study from our observation that TCE elevated LRRK2 kinase activity in the nigrostriatal tract of rats prior to dopaminergic neurodegeneration. We found that LRRK2 inhibition blocked toxicant-induced ROS and promoted mitophagy in vitro, and protected against dopaminergic neurodegeneration, neuroinflammation, and mitochondrial damage caused by TCE in vivo. We also found that cells with the LRRK2 G2019S mutation displayed exacerbated levels of toxicant induced ROS, but this was ameliorated by LRRK2 inhibition with MLi2. Collectively, these data support a role for LRRK2 in toxicant-induced mitochondrial dysfunction linked to PD risk through oxidative stress and the autophagic removal of damaged mitochondria.

Development of a slow-release CO2 absorbent material for alkaline activation of persulfate oxidation of TCE and CO2 capture

Control of carbon dioxide (CO2) emission during chemical oxidation processes of organic-chemical contaminated sites has become a challenge. In this study, a novel slow-release CO2 absorbent material (SCAM) was developed for a slow release of Ca2+ and OH–, which were used for CO2 capture, pH adjustment, and alkaline activation of persulfate (PS) oxidation for trichloroethylene (TCE) degradation. The SCAM was produced using basic oxygen furnace slag (BOFs) and calcium sulfate hemihydrate (CSH) as the components for granulation and modification. Batch experiments were conducted to determine the optimal mass ratio of BOFs to CSH and evaluate CO2 capture capacity and SCAM performance. An increase in BOFs proportion led to a higher CO2 capture capacity, with the maximum capture amount reaching 156 g CO2/kg SCAM. An excessive addition of BOFs resulted in an overly alkaline pH value (pH = 12.4), causing the diminished PS oxidation efficiency. The optimal mass ratio of BOFs to CSH (1 to 1) could capture produced CO2 after TCE oxidation without inhibiting PS oxidation. The SCAM could serve as the catalyst and activate PS oxidation, resulting in 93.1 % of TCE oxidation (initial TCE concentration = 2.32 mM) and 95.4 % of CO2 emission reduction due to the formation of CaCO3 precipitates under alkaline conditions. Produced sulfate and hydroxyl radicals confirmed the PS oxidation of TCE using SCAM as an activator. The developed SCAM is a green catalyst for PS oxidation and it is also an effective CO2 absorbent. SCAM can reduce CO2 emission due to the formation of CaCO3 precipitates under alkaline conditions. The released OH– could also prevent the acidification problem caused by the production of sulfuric acid through PS decomposition.

Cesium ion-guided detection of trichloroethylene in air

Whereas the close associations of cesium ion with organochlorine compounds have been previously documented, the present report is the first attempt to exploit these interactions to create a trichloroethylene (TCE)-selective sensor. Gold monolayer-protected clusters peripherally functionalized with Cs+ ions were used to prepare a chemiresistance film on MEMS-fabricated interdigitated electrodes. Vapor sensing properties of the cesium-rich chemiresistor were determined using a panel of chlorinated hydrocarbons including TCE as well as polar and non-polar VOCs for comparison. The sensor was selective and highly sensitive toward VOCs containing a 1,2-dichloro group at concentrations as low as 0.1 ppm. The results suggest the key interaction contributing to sensor response is a bidentate, metallocycle-like coordination of the 1,2-dichloro group to the cesium cations at the sensor surface.

Biodegradation of Trichloroethylene by Trametes versicolor and its Physiological Response to Contaminant Stress.

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.

TCE degradation of modified graphite felt cathode in a flow-through electro-Fenton system and its H2O2 production ability in a real contaminated field

A modified graphite felt (MGF) was prepared with carbon black (CB) and polytetrafluoron (PTFE) for cathodic electrochemical H2O2 production, which was used in a flow-through cathodic electro-Fenton reactor to degrade chlorinated hydrocarbons. Cathode electrode was floating on aqueous surface and 369.1 mg/L H2O2 could be produced after 1 h 150 mA power applied without O2 aeration. The main O2 source for H2O2 production was confirmed from air with this floating position. In a 2.0 L flow-through cathodic electro-Fenton system, 95.97 % degradation efficiency for 5.0 mg/L trichloroethylene (TCE) was achieved in 90 min with 13.4 mL/min influent rate. Reducing the reactor volume to 0.14 L, 5.0 mg/L TCE could be degraded completely in 10 min with continuous 4 L influent. The mixed chlorinated hydrocarbons (TCE, cis-1,1-dichloroethylene, 1,2-dichloroethane, and dichloromethane) were also rapidly degraded in 20 min. The flow-through cathodic electro-Fenton reactor presented excellent degradation ability for chlorinated hydrocarbons with a smaller volume. In the simulated sand tank system, after continuously operated 27 days, H2O2 concentration in electrode well was still remained at 80 mg/L. In the contaminated field in Tianjin, China, H2O2 yield of MGF in groundwater could keep at about 60 mg/L after 220 min operating.

Bone char switch on reductive dehalogenation of trichloroethene by series of Fe(II)-bearing minerals: The balance between kinetics and electron efficiency

Fe(II)-bearing minerals might be able to drive the attenuation of chlorinated ethene in soil and groundwater, however, with relatively slow kinetics. In this study, bone char(BC) was selected as an efficient and benign catalyst to prepare composites with three different Fe(II)-bearing minerals (Green rust (GR), Fe(OH)2 and FeS), respectively, for enhanced trichloroethylene (TCE) dehalogenation. The kinetics experiment demonstrated that the presence of BC could effectively switch on the TCE dehalogenation by these solids, while these Fe(II)-bearing minerals alone can barely reduce any TCE. Surprisingly, the Fe(OH)2-BC showed fastest TCE reduction rate, followed by GR-BC and FeS-BC in sequence. Acetylene was confirmed as the major dehalogenation products while other chlorinated byproducts were hardly detected. The electron efficiency (ηe) for TCE reduction was further calculated and compared among these BC amended systems, the results show that the highest ηe value was recorded in GR-BC system as 33.14% with high loading of TCE. Solid phase characterization confirmed that the high loading of amorphous Fe(II) on the BC surface might effectively improve the TCE dehalogenation kinetics, while the well crystallized Fe(II)-bearing minerals would increase the electron efficiency. According to this mechanism, it might be possible to achieve balance between kinetics and electron efficiency. Stress resistance test in real groundwater matrix and life cycle analysis (LCA) was conducted to further verify the application potential of these composites.

Influence of microbial inoculation site on trichloroethylene degradation in electrokinetic-enhanced bioremediation of low-permeability soils

The integration of electrokinetic and bioremediation (EK-BIO) represents an innovative approach for addressing trichloroethylene (TCE) contamination in low-permeability soil. However, there remains a knowledge gap in the impact of the inoculation approach on TCE dechlorination and the microbial response with the presence of co-existing substances. In this study, four 1-dimensional columns were constructed with different inoculation treatments. Monitoring the operation conditions revealed that a stabilization period (∼40 days) was required to reduce voltage fluctuation. The group with inoculation into the soil middle (Group B) exhibited the highest TCE dechlorination efficiency, achieving a TCE removal rate of 84%, which was 1.1–3.2 fold higher compared to the others. Among degraded products in Group B, 39% was ethylene. The physicochemical properties of the post-soil at different regions illustrated that dechlorination coincided with the Fe(III) and SO42− reduction, meaning that the EK-BIO system promoted the formation of a reducing environment. Microbial community analysis demonstrated that Dehalococcoides was only detected in the treatment of injection at soil middle or near the cathode, with abundance enriched by 2.1%–7.2%. The principal components analysis indicated that the inoculation approach significantly affected the evolution of functional bacteria. Quantitative polymerase chain reaction (qPCR) analysis demonstrated that Group B exhibited at least 2.8 and 4.2-fold higher copies of functional genes (tceA, vcrA) than those of other groups. In conclusion, this study contributes to the development of effective strategies for enhancing TCE biodechlorination in the EK-BIO system, which is particularly beneficial for the remediation of low-permeability soils.

Microplastic inhibits the sorption of trichloroethylene on modified biochar.

Biochar (BC) was used to remove trichloroethylene (TCE) from soil and water phases, and BC modification changed the sorption behavior of pollutants. Microplastics are emerging pollutants in the soil and water phases. Whether microplastics can affect the sorption of TCE by modified BC is not clear. Thus, batch sorption kinetics and isotherm experiments were conducted to elucidate the sorption of TCE on BC, and BC combined with polyethylene (PE) or polystyrene (PS). The results showed that HCl and NaOH modification increased TCE sorption on BC, while HNO3 modification inhibited TCE sorption on BC. When PE/PS and BC coexisted, the TCE sorption capacity decreased significantly on BC-CK + PE, BC-HCl + PE, BC-HNO3 + PE, BC-NaOH + PE, and BC-NaOH + PS, which was likely due to the preferential sorption of PE/PS on BC samples. We concluded that microplastics can change TCE sorption behavior and inhibit TCE sorption on BC samples. Thus, the interaction of BC and microplastics should be considered when BC is used for TCE removal in soil and water remediation.

Highly efficient bioregeneration of high temperature-pyrolyzed biochar after trichloroethylene adsorption through biodegradation of Dehalococcoides

Biochars was widely employed to immobilize chlorinated aliphatic hydrocarbons (CAHs) in groundwater. Biodegradation of adsorbed CAHs may be able to regenerate biochars, but was scarcely explored. In this study, therefore, biodegradation of trichloroethylene (TCE) adsorbed on a biochar prepared at 700 °C (WBC700) by Dehalococcoides mccartyi 195 (Dhc 195) was investigated. Aqueous TCE was completely degraded to ethene by Dhc 195 within 28 days, while 87.5 % of WBC700-adsorbed TCE was degraded to ethene within 63 days. The slower biodegradation of WBC700-adsorbed TCE could be attributed to its lower accessibility to Dhc 195 caused by the steric effects of WBC700. The adsorption capacity of WBC700 for TCE remained 80.4 % after five adsorption-bioregeneration cycles, indicating that the microbial degradation could be a highly efficient method to regenerate biochars. The microbial degradation was mainly through the electron transfer from Dhc 195 to TCE mediated by biochars as electron conductor or shuttle, but was not assisted by desorption or extracellular redox active species. Compared with biodegradation of aqueous TCE, the biodegradation of WBC700-adsorbed TCE by Dhc 195 had a wider pH tolerance and required more VB12, due to the buffer effect and adsorption of WBC700, respectively. The obtained results could provide a cost-effective method of biochar regeneration for CAHs removal in groundwater.

Acetylene Tunes Microbial Growth During Aerobic Cometabolism of Trichloroethene.

Microbial aerobic cometabolism is a possible treatment approach for large, dilute trichloroethene (TCE) plumes at groundwater contaminated sites. Rapid microbial growth and bioclogging pose a persistent problem in bioremediation schemes. Bioclogging reduces soil porosity and permeability, which negatively affects substrate distribution and contaminant treatment efficacy while also increasing the operation and maintenance costs of bioremediation. In this study, we evaluated the ability of acetylene, an oxygenase enzyme-specific inhibitor, to decrease biomass production while maintaining aerobic TCE cometabolism capacity upon removal of acetylene. We first exposed propane-metabolizing cultures (pure and mixed) to 5% acetylene (v v-1) for 1, 2, 4, and 8 d and we then verified TCE aerobic cometabolic activity. Exposure to acetylene overall decreased biomass production and TCE degradation rates while retaining the TCE degradation capacity. In the mixed culture, exposure to acetylene for 1-8 d showed minimal effects on the composition and relative abundance of TCE cometabolizing bacterial taxa. TCE aerobic cometabolism and incubation conditions exerted more notable effects on microbial ecology than did acetylene. Acetylene appears to be a viable approach to control biomass production that may lessen the likelihood of bioclogging during TCE cometabolism. The findings from this study may lead to advancements in aerobic cometabolism remediation technologies for dilute plumes.

Trichloroethylene metabolite modulates DNA methylation-dependent gene expression in Th1-polarized CD4+ T cells from autoimmune-prone mice.

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.

Bioremediation of trichloroethylene-contaminated groundwater using green carbon-releasing substrate with pH control capability

In this research, a sustainable substrate, termed green and long-lasting substrate (GLS), featuring a blend of emulsified substrate (ES) and modified rice husk ash (m-RHA) was devised. The primary objective was to facilitate the bioremediation of groundwater contaminated with trichloroethylene (TCE) using innovative GLS for slow carbon release and pH control. The GLS was concocted by homogenizing a mixture of soybean oil, surfactants (Simple Green™ and soya lecithin), and m-RHA, ensuring a gradual release of carbon sources. The hydrothermal synthesis was applied for the production of m-RHA production. The analyses demonstrate that m-RHA were uniform sphere-shape granules with diameters in micro-scale ranges. Results from the microcosm study show that approximately 83% of TCE could be removed (initial TCE concentration = 7.6 mg/L) with GLS supplement after 60 days of operation. Compared to other substrates without RHA addition, higher TCE removal efficiency was obtained, and higher Dehalococcoides sp. (DHC) population and hydA gene (hydrogen-producing gene) copy number were also detected in microcosms with GLS addition. Higher hydrogen concentrations enhanced the DHC growth, which corresponded to the increased DHC populations. The addition of the GLS could provide alkalinity at the initial stage to neutralize the acidified groundwater caused by the produced organic acids after substrate biodegradation, which was advantageous to DHC growth and TCE dechlorination. The addition of m-RHA reached an increased TCE removal efficiency, which was due to the fact that the m-RHA had the zeolite-like structure with a higher surface area and lower granular diameter, and thus, it resulted in a more effective initial adsorption effect. Therefore, a significant amount of TCE could be adsorbed onto the surface of m-RHA, which caused a rapid TCE removal through adsorption. The carbon substrates released from m-RHA could then enhance the subsequent dechlorination. The developed GLS is an environmentally-friendly and green substrate.

Unveiling the mechanisms of trichloroethylene hypersensitivity syndrome: Exploring the role of connexin 43 gap junctions in severe skin damage

Trichloroethylene (TCE), extensively used as an organic solvent in various industrial applications, has been identified as a causative factor in inducing hypersensitivity syndrome (THS). Currently, there is no specific treatment for THS, and most patients experience serious adverse outcomes due to extensive skin damage leading to severe infection. However, the pathogenesis of THS-associated skin damage remains unclear. This study aims to elucidate the mechanism underlying skin damage from the perspective of intercellular communication and gap junctions in THS. Our results verified that hyperactivation of connexin43 gap junctions, caused by the aberrantly elevated expression of connexin43, triggers a bystander effect that promotes apoptosis and inflammation in THS via the TNF-TNFRSF1B and mitochondria-associated pathways. Additionally, we identified the gap junction inhibitor Carbenoxolone disodium (CBX) as a promising agent for the treatment of skin damage in THS. CBX protects against inflammatory cell infiltration in the skin and decreases immune cell imbalance in the peripheral blood of THS mice. Furthermore, CBX reduces connexin43 expression, apoptosis and inflammation in THS mice. The study reveals new insights into the mechanisms underlying TCE-induced skin damage, offering a potential treatment strategy for the development of effective therapies targeting severe dermatitis induced by chemical exposure.

Metagenomic sequencing reveals mechanisms of adaptation and biodegradation of dechlorinating bacteria to trichloroethylene

Bioremediation is a sustainable, cost-effective, and eco-friendly way to remediate pollutants. However, the effectiveness of bioremediation is constrained by the underground environmental conditions, resulting in poor natural attenuation of organic pollution and degradation by functional microorganisms. In this study, a dechlorinating bacteria (DB) was enriched from contaminated soil and used to degrade trichloroethylene (TCE) in wastewater. The adaptation and degradation mechanisms of DB to TCE were investigated by degradation product analysis and metagenomic sequencing. The degradation of TCE by DB is pH and additional carbon source dependent. The highest TCE removal amount (1.86 × 10−7 mmol/CFU) was achieved at pH=8, 1% DB inoculum volume, and 400 mg/L sodium acetate concentration. Moreover, DB has a high acid resistance and a removal capacity of 1.18×10−7 mmol/CFU for TCE at pH =2. None of the co-occurring pollutants Cr (VI) and toluene had a significant effect on the ability of DB to degrade TCE in wastewater (maintained at 1.13–1.22×10−7 mmol/CFU). DB dechlorinated TCE mainly through the action of extracellular enzymes (contributed 91% of the total removal ability). DB playing a major role in degradation is Paraclostridium. Significant differences in alpha diversity indices were revealed in the reaction systems after 15 days of exposure to TCE (p < 0.01). The degradation of TCE by DB is mainly accomplished through the defense system, energy synthesis, electron supply and biodegradation. Metagenomic sequencing demonstrated that DB achieved adaptation and degradation of TCE through gene-regulated biological processes such as xenobiotic biodegradation and metabolism, carbohydrate metabolism, biosynthesis of other secondary metabolites, amino acid metabolism, membrane transport, and signal transduction. This study reveals for the first time the biodegradation efficiency and biotransformation process of DB under TCE stress.

Granulysin-mediated reduction of PDZRN3 induces Cx43 gap junctions activity exacerbating skin damage in trichloroethylene hypersensitivity syndrome

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.

Real-time monitoring and predictive analysis of VOC flux variations in soil vapor: Integrating PID sensing with machine learning for enhanced vapor intrusion forecasts

In the rapidly evolving domain of vapor intrusion (VI) assessments, traditional methodologies encompass detailed groundwater and soil vapor sampling coupled with comprehensive laboratory measurements. These models, blending empirical data, theoretical equations, and site-specific parameters, evaluate VI risks by considering a spectrum of influential factors, from volatile organic compounds (VOC) concentrations in groundwater to nuanced soil attributes. However, the challenge of variability, influenced by dynamic ambient conditions and intricate soil properties, remains. Our study presents an advanced on-site gas sensing station geared towards real-time VOC flux monitoring, enriched with an array of ambient sensors, and spearheaded by the reliable PID sensor for VOC detection. Integrating this dynamic system with machine learning, we developed predictive models, notably the random forest regression, which boasts an R-squared value exceeding 79 % and mean relative error near 0.25, affirming its capability to predict trichloroethylene (TCE) concentrations in soil vapor accurately. By synergizing real-time monitoring and predictive insights, our methodology refines VI risk assessments, equipping communities with proactive, informed decision-making tools and bolstering environmental safety. Implementing these predictive models can simplify monitoring for residents, reducing dependence on specialized systems. Once proven effective, there's potential to repurpose monitoring stations to other VI-prone regions, expanding their reach and benefit. The developed model can leverage weather forecasting data to predict and provide alerts for future VOC events.

Effect of Pt nanoparticle size on resistance to chloride-induced inhibition for hydrodechlorination of trichloroethylene in water

Catalysts used for hydrodechlorination (HDC) of trichloroethylene (TCE) undergo partial or complete loss of catalytic activity due to inhibition by inevitable reaction product HCl. Changing the size of Pt NPs could be used as a strategy to prevent inhibition of HDC catalysts if the structure sensitivity of the reaction was known. This study aims to obtain structure-sensitivity of aqueous-phase HDC of TCE and investigate the effect of Pt NPs’ size on resistance to chloride inhibition. The research encompassed the synthesis of Pt NPs, characterization studies, and catalytic activity measurements at 30 °C & 1 atm H2 in batch or discontinuous pulse mode. Characterization results showed that targeted Pt NPs were successfully synthesized with average particle sizes of 3.0 nm, 5.8 nm, 8.9 nm, and 60.9 nm. Catalytic activity experiments revealed that initial turnover frequency values exhibited a decrease with increasing particle size of Pt NPs, indicating that aqueous-phase HDC of TCE is a structure sensitive reaction. The fastest kinetics and the highest resistance to HCl inhibition were observed over the smallest Pt NPs employed in this study. This information can serve as a rational synthesis parameter for designing catalysts that could mitigate chloride inhibition caused by the reaction product HCl.

Aerobic biodegradation of chlorinated ethenes by Pseudonocardia sp. D17: Biodegradation ability without auxiliary substrates and concurrent biodegradation with 1,4-dioxane

Bioremediation is a promising approach for mitigating commingled contaminations of chlorinated ethenes (CEs) and 1,4-dioxane (DX). However, aerobic bioremediation to simultaneously remove CEs and DX remains challenging. This study aimed to explore the ability of Pseudonocardia sp. D17 (D17) to aerobically degrade CEs and its applicability for concurrent removal of CEs and DX. Aerobic degradation experiments of individual CEs revealed that D17 could degrade trichloroethene (TCE), three isomers of dichloroethene (DCE), and vinyl chloride (VC), and the trend of its degradation ability was cis-1,2-DCE (cDCE) > VC > TCE >trans-1,2-DCE > 1,1-DCE. Notably, the CE-degrading activity of D17 was expressed even without any auxiliary substrates. Further, when TCE, cDCE, or VC was co-present with DX (each at 1 mg/L), D17 could degrade both compounds without any significant inhibition (for TCE and cDCE) or with only a transient and reversible suspension of its DX degradation ability (for VC). These findings indicated that D17 is a promising agent for the aerobic bioremediation of CEs and DX co-contamination and provide novel insights into the future development of efficient aerobic bioremediation strategies.