Higher thermal remediation temperature facilitates the sequential bioaugmented reductive dechlorination.

The coupling of thermal remediation with microbial reductive dechlorination (MRD) has shown promising potential for the cleanup of chlorinated solvent contaminated sites. In this study, thermal treatment and bioaugmentation were applied in series, where prior higher thermal remediation temperature led to improved TCE dechlorination performance with both better organohalide-respiring bacteria (OHRB) colonization and electron donor availability. The 60 °C was found to be a key temperature point where the promotion effect became obvious. Amplicon sequencing and co-occurrence network analysis demonstrated that temperature was a more dominating factor than bioaugmentation that impacted microbial community structure. Higher temperature of prior thermal treatment resulted in the decrease of richness, diversity of indigenous microbial communities, and simplified the network structure, which benefited the build-up of newcoming microorganisms during bioaugmentation. Thus, the abundance of Desulfitobacterium increased from 0.11 % (25 °C) to 3.10 % (90 °C). Meanwhile, released volatile fatty acids (VFAs) during thermal remediation functioned as electron donors and boosted MRD. Our results provided temperature-specific information on synergistic effect of sequential thermal remediation and bioaugmentation, which contributed to better implementation of the coupled technologies in chloroethene-impacted sites.

Spatiotemporal dynamic temperature variation dominated by ion behaviors during groundwater remediation using direct current.

Direct current (DC) electric field has shown promising performance in contaminated site remediation, in which the Joule heating effect plays an important role but has been previously underappreciated. This study focuses on the spatiotemporal characteristics and mechanism of temperature change in heterogeneous porous media with applied DC. The heating process can be divided into four phases: preferential heating of the low permeability zone (LPZ), rapid heating in the middle region, temperature drop and hot zone shift, and reheating. The dynamic ion behaviors with complex interplays among reactions, electrokinetic-driven migration, and mixed convection induced an uneven redistribution of ions and dominated the heating rate and temperature distribution. The concentration of major ions near the pH jump decreased to 1% of the initial value, even though ions were continuously pumped into the heating zone. This ion depletion caused a drop in current, heating rate, and temperature. Here ions cannot be delivered rapidly into the ion-depleted zone by electromigration due to the potential flattening in the surrounding region. The presence of LPZ intensified the nonuniformity of ion redistribution, where a regional focusing of water-soluble ions was observed, and weakened the temperature rebound compared with that using homogeneous sand. These results provide a new perspective on the regulation of DC heating in site remediation.

Microbial diversity and metabolic pathways linked to benzene degradation in petrochemical-polluted groundwater.

The rapid advance in shotgun metagenome sequencing has enabled us to identify uncultivated functional microorganisms in polluted environments. While aerobic petrochemical-degrading pathways have been extensively studied, the anaerobic mechanisms remain less explored. Here, we conducted a study at a petrochemical-polluted groundwater site in Henan Province, Central China. A total of twelve groundwater monitoring wells were installed to collect groundwater samples. Benzene appeared to be the predominant pollutant, detected in 10 out of 12 samples, with concentrations ranging from 1.4 µg/L to 5,280 µg/L. Due to the low aquifer permeability, pollutant migration occurred slowly, resulting in relatively low benzene concentrations downstream within the heavily polluted area. Deep metagenome sequencing revealed Proteobacteria as the dominant phylum, accounting for over 63 % of total abundances. Microbial α-diversity was low in heavily polluted samples, with community compositions substantially differing from those in lightly polluted samples. dmpK encoding the phenol/toluene 2-monooxygenase was detected across all samples, while the dioxygenase bedC1 was not detected, suggesting that aerobic benzene degradation might occur through monooxygenation. Sequence assembly and binning yielded 350 high-quality metagenome-assembled genomes (MAGs), with 30 MAGs harboring functional genes associated with aerobic or anaerobic benzene degradation. About 80 % of MAGs harboring functional genes associated with anaerobic benzene degradation remained taxonomically unclassified at the genus level, suggesting that our current database coverage of anaerobic benzene-degrading microorganisms is very limited. Furthermore, two genes integral to anaerobic benzene metabolism, i.e, benzoyl-CoA reductase (bamB) and glutaryl-CoA dehydrogenase (acd), were not annotated by metagenome functional analyses but were identified within the MAGs, signifying the importance of integrating both contig-based and MAG-based approaches. Together, our efforts of functional annotation and metagenome binning generate a robust blueprint of microbial functional potentials in petrochemical-polluted groundwater, which is crucial for designing proficient bioremediation strategies.

Microbial functional heterogeneity induced in a petroleum-polluted soil profile.

Microbial taxonomic diversity declines with increasing stress caused by petroleum pollution. However, few studies have tested whether functional diversities vary similarly to taxonomic diversity along the stress gradient. Here, we investigated soil microbial communities in a petrochemically polluted site in China. Total petroleum hydrocarbon (TPH) concentrations were higher in the middle (2-3 m) and deep soil layer (3-5 m) than in the surface soil layer (0-2 m). Accordingly, microbial taxonomic α-diversity was decreased by 44% (p < 0.001) in the middle and deep soil layers, compared to the surface soil layer. In contrast, functional α-diversity decreased by 3% (p < 0.001), showing a much better buffering capacity to environmental stress. Differences in microbial taxonomic and functional ß-diversities were enlarged in the middle and deep soil layers, extending the Anna Karenina Principle (AKP) that a community adapts to stressful environments in its own way. Consistent with the stress gradient hypothesis, we revealed a higher degree of network connectivity among microbial species and genes in the middle and deep soil layers compared to the surface soil layer. Together, we demonstrate that microbial functionality is more tolerant to stress than taxonomy, both of which were amenable to AKP and the stress gradient hypothesis.

Synergistic/antagonistic toxicity characterization and source-apportionment of heavy metals and organophosphorus pesticides by the biospectroscopy-bioreporter-coupling approach.

Many anthropogenic chemicals are manufactured and eventually enter the surrounding environment, threatening food security and human health. Considering the additive or synergistic effects of pollutant mixtures, there is an expanding need for rapid, cost-effective and field-portable screening methods in environmental monitoring. This study used a recently developed biospectroscopy-bioreporter-coupling (BBC) approach to investigate the binary toxicity of Ag(I), Cr(VI) and four organophosphorus pesticides (dichlorvos, parathion, omethoate and monocrotophos). Ag(I) and Cr(VI) altered the toxicity mechanisms of pesticides, explained by the synergistic or antagonistic effect of Ag/Cr-induced cytotoxicity and pesticide-induced genotoxicity. The discriminating Raman spectral peaks associated with organophosphorus pesticides were 1585 and 1682 cm-1, but 750, 1004, 1306 and 1131 cm-1 were found in heavy metal and pesticide mixtures. More spectral alterations were related to pesticides rather than Ag(I) or Cr(VI), hinting at the dominant toxicity mechanisms of pesticides in mixtures. Ag(I) supplement significantly increased the levels of reactive oxygen species induced by organophosphorus pesticides, attributing to the increased permeability of cell membrane and entrance of toxic substances into the cells by the oligodynamic actions. This study lends deeper insights into the interactions between microbes and pollutant mixtures, offering clues to assess the cocktail effects of multiple pollutants comprehensively.

Three-dimensional nonlinear model of rock creep under freeze-thaw cycles.

In areas with large differences between day and night temperature, the freeze-thaw cycle and frost heaving force in rock mass generate cracks within the rock, which seriously threatens the stability and safety of geotechnical engineering structures and surrounding buildings. This problem can be solved by developing a reasonable model that accurately represents the rock creep behavior. In this study, we developed a nonlinear viscoelastic-plastic creep damage model by introducing material parameters and a damage factor while connecting an elastomer, a viscosity elastomer, a Kelvin element, and a viscoelastic-plastic element in series. One- and three-dimensional creep equations were derived, and triaxial creep data were used to determine the model parameters and to validate the model. The results showed that the nonlinear viscoelastic-plastic creep damage model can accurately describe rock deformation in three creep stages under freeze-thaw cycles. In addition, the model can describe the time-dependent strain in the third stage. Parameters G1, G2, and η20' decrease exponentially with the increase in the number of freeze-thaw cycles while parameter λ increases exponentially. These results provide a theoretical basis for studying the deformation behavior and long-term stability of geotechnical engineering structures in areas with large diurnal temperature differences.

Application of magnetic-nanoparticle functionalized whole-cell biosensor array for bioavailability and ecotoxicity estimation at urban contaminated sites.

The bioavailability and ecotoxicity of pollutants are important for urban ecological systems and human health, particularly at contaminated urban sites. Therefore, whole-cell bioreporters are used in many studies to assess the risks of priority chemicals; however, their application is restricted by low throughput for specific compounds and complicated operations for field tests. In this study, an assembly technology for manufacturing Acinetobacter-based biosensor arrays using magnetic nanoparticle functionalization was developed to solve this problem. The bioreporter cells maintained high viability, sensitivity, and specificity in sensing 28 priority chemicals, seven heavy metals, and seven inorganic compounds in a high-throughput manner, and their performance remained acceptable for at least 20 d. We also tested the performance by assessing 22 real environmental soil samples from urban areas in China, and our results showed positive correlations between the biosensor estimation and chemical analysis. Our findings prove the feasibility of the magnetic nanoparticle-functionalized biosensor array to recognize the types and toxicities of multiple contaminants for online environmental monitoring at contaminated sites.

Petroleum pollution changes microbial diversity and network complexity of soil profile in an oil refinery.

Introduction: Petroleum pollution resulting from spills and leakages in oil refinery areas has been a significant environmental concern for decades. Despite this, the effects of petroleum pollutants on soil microbial communities and their potential for pollutant biodegradation still required further investigation. Methods: In this study, we collected 75 soil samples from 0 to 5 m depths of 15 soil profiles in an abandoned refinery to analyze the effect of petroleum pollution on soil microbial diversity, community structure, and network co-occurrence patterns. Results: Our results suggested soil microbial a-diversity decreased under high C10-C40 levels, coupled with significant changes in the community structure of soil profiles. However, soil microbial network complexity increased with petroleum pollution levels, suggesting more complex microbial potential interactions. A module specific for methane and methyl oxidation was also found under high C10-C40 levels of the soil profile, indicating stronger methanotrophic and methylotrophic metabolic activities at the heavily polluted soil profile. Discussion: The increased network complexity observed may be due to more metabolic pathways and processes, as well as increased microbial interactions during these processes. These findings highlight the importance of considering both microbial diversity and network complexity in assessing the effects of petroleum pollution on soil ecosystems.

Dual effects of PFOA or PFOS on reductive dechlorination of trichloroethylene (TCE).

PFASs and chlorinated solvents are the common co-contaminants in soil and groundwater at firefighter training areas (FTAs). Although PFASs mixtures could have adverse impacts on bioremediation of trichloroethylene (TCE) by inhibiting Dehalococcoides (Dhc), little is known about the effect and contribution of PFOA or PFOS on dechlorination of TCE by non-Dhc organohalide-respiring bacteria (OHRB). To study this, PFOA and PFOS were amended to the growth medium of a non-Dhc OHRB-containing enrichment culture to determine the impact on dechlorination. This study demonstrated that high levels of PFOA or PFOS (100 mg L-1) inhibited TCE dechlorination in four non-Dhc OHRB-containing community including Geobacter, Desulfuromonas, Desulfitobacterium, and Dehalobacter, but low levels of PFOA or PFOS (≤10 mg L-1) enhanced TCE dechlorination. Four non-Dhc OHRB were less inhibited by PFOA than that by PFOS, and high level of PFOS killed Desulfitobacterium and Dehalobacter and decreased the biodiversity of bacterial community. Although most fermenters were killed by the presence of 100 mg L-1 PFOS, two important co-cultures (Desulfovibrio and Sedimentibacter) of OHRB were enriched, indicating that the syntrophic relationships between OHRB and co-cultures still remained, and PFOA or PFOS inhibited TCE dechlorination by directly repressing non-Dhc OHRB. Our results highlight that the bioattenuation of chloroethene contamination could be confounded by non-Dhc OHRB in high levels of PFOS contaminated subsurface environments at FTAs.

Consistency evaluation of exercise target heart rate determined by resting heart rate and anaerobic threshold in chronic heart failure patients.

PURPOSE: To evaluate the consistency on the target heart rate for exercise determined by simple target heart rate (sTHR) based on resting heart rate (HRrest) and heart rate at anaerobic threshold (HRAT) in cardiopulmonary exercise test (CPET) for patients with chronic heart failure. METHODS: This is a retrospective cohort study, in which CHF patients who underwent CPET in Tongji Hospital Cardiac Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were enrolled. The clinical data of the patients from the electronic medical record system, HRrest and HRAT measured by CPET were collected. Patients were further divided into subgroups according to gender, age (<60 years group and ≥ 60 years group), with or without beta-blocker therapy and subgroup of heart failure (heart failure with reduced, mid-range and preserved ejection fraction). The sTHR (HRrest plus 10, 15, 20, 25 and 30 bpm) and HRAT were all calculated in each patient. Paired t-test was used for the difference between the two methods, correlation analysis was shown by pearson analysis and intraclass correlation coefficient (ICC) was calculated for consistency test. RESULTS: A total of 547 CHF patients were enrolled, including 447 males (81.7%), aged 63 (56,69) years, with BMI of 25.2 (23.5,26.4) kg/m2 and LVEF of 45.0 (36.0, 52.0) %. The target heart rate determined by HRAT method was (93.59 ± 13.95) bpm, and its counterpart determined by HRrest plus 20 bpm (HRrest+20) was (93.16 ± 7.69) bpm. There was no significant difference between the two methods (P>0.05). However, it was statistically different between HRrest plus 10, 15, 25, 30 bpm and HRAT respectively (P<0.001). And HRrest+20 was positively correlated with HRAT (r = 0.418, P<0.001). Therefore, HRrest+20 below was regarded as sTHR. The ICC of the consistency test between sTHR and HRAT was 0.523,95%CI 0.435-0.596 (P < 0.001) in all patients (n = 547). In patients with beta-blocker therapy (n = 464), the ICC of sTHR and HRAT consistency test was 0.534,95%CI 0.441-0.612, P < 0.001; The ICC of the consistency test between sTHR and HRAT of patients without beta-blocker therapy (n = 83) was 0.407,95%CI 0.083-0.616, P < 0.05. In the sinus rhythm group (n = 466), the ICC of sTHR and HRAT consistency test was 0.527,95%CI 0.433-0.606, P < 0.001; The ICC of the consistency test between sTHR and HRAT of atrial fibrillation patients in group (n = 81) was 0.482,95%CI 0.195-0.667, P < 0.05.The ICC of the consistency test between sTHR and HRAT was 0.501,95%CI 0.338-0.623 (P < 0.001) in patients under 60 years old (n = 195); The ICC of the consistency test between sTHR and HRAT in patients ≥60 years old (n = 352) was 0.533,95%CI 0.424-0.621, P < 0.001. In the male group (n = 447), the ICC of sTHR and HRAT consistency test was 0.577,95%CI 0.491-0.649, P < 0.001; The ICC of the consistency test between sTHR and HRAT of female patients in group (n = 100) was 0.344,95%CI 0.025-0.559, P < 0.05. The ICC of sTHR and HRAT consistency test in HFrEF group (n = 170) was 0.395,95%CI 0.181-0.553, P < 0.01; The ICC values of the consistency test between sTHR and HRAT was 0.543, 95%CI 0.405-0.649 (P < 0.001) in patients with HFmrEF (n = 222); In HFpEF group (n = 155), the ICC of sTHR and HRAT consistency test was 0.620,95%CI 0.478-0.723, P < 0.001. CONCLUSION: The exercise target heart rate calculated by HRrest is consistent with that determined by HRAT in patients with CHF. For primary hospitals without CPET, exercise prescription equivalent to AT intensity for patients with CHF can be determined by HRrest. However, the target heart rate calculated by HRrest can't replace that determined by HRAT in this patient cohort completely.

Toxicity Characterization of Environment-Related Pollutants Using a Biospectroscopy-Bioreporter-Coupling Approach: Potential for Real-World Toxicity Determination and Source Apportionment of Multiple Pollutants.

Exposure to environmental pollutants occurs ubiquitously and poses many risks to human health and the ecosystem. Although many analytical methods have been developed to assess such jeopardies, the circumstances applying these means are restricted to linking the toxicities to compositions in the pollutant mixtures. The present study proposes a novel analytical approach, namely, biospectroscopy-bioreporter-coupling (BBC), to quantify and apportion the toxicities of metal ions and organic pollutants. Using a toxicity bioreporter ADPWH_recA and Raman spectroscopy, both bioluminescent signals and spectral alterations had similar dosage- and time-response behavior to the toxic compounds, validating the possibility of coupling these two methods from practical aspects. Raman spectral alterations successfully distinguished the biomarkers for different toxicity mechanisms of individual pollutants, such as ring breathing mode of DNA/RNA bases (1373 cm-1) by Cr, reactive oxygen species-induced peaks of proteins (1243 cm-1), collagen (813 cm-1), and lipids (1255 cm-1) by most metal ions, and indicative fingerprints of organic toxins. The support vector machine model had a satisfactory performance in distinguishing and apportioning toxicities of individual toxins from all input data, achieving a sensitivity of 88.54% and a specificity of 97.80%. This work set a preliminary database for Raman spectral alterations of whole-cell bioreporter response to multiple pollutants. It proved the state-of-the-art concept that the BBC approach is feasible to rapidly quantify and precisely apportion toxicities of numerous pollutant mixtures.

Change of the structure and assembly of bacterial and photosynthetic communities by the ecological engineering practices in Dianchi Lake.

Cyanobacterial bloom challenges the aquatic ecosystem and ecological restoration is an effective approach for cyanobacterial bloom control, but the change of aquatic community after ecological restoration is still unclear. Dianchi Lake is an eutrophic lake with frequent cyanobacterial blooms in China, and recent ecological restoration projects in Caohai (north part) have a satisfactory performance. In this study, we collected 249 water samples at 23 sites from Dianchi Lake to explore the relationships between water physicochemical variables and aquatic microbial communities. Water physicochemical variables in Waihai (south part) intensively changed along time, whereas those in Caohai did not. Photoautotrophic communities were significantly divergent between Caohai and Waihai. Waihai had a lower diversity of photoautotrophic community, containing higher abundance of Cyanophyceae (89.9%) than Caohai (42.7%). Nutrient level and Cyanophyceae only exhibited strong correlations in Wahai (p < 0.05). Redundancy analysis and microbial ecological network suggested that microbial communities in Caohai had a higher stability. Deterministic process dominated the microbial assembly (50-80% for bacteria and >90% for photoautotrophs), and particularly in Caohai. Our results unraveled that the structure and assembly of bacterial and photoautotrophic communities significantly changed after ecological restoration, offering valuable suggestions that photosynthetic diversity should be focused for other ecological restoration projects.

Simultaneous removal of nitrate, nitrobenzene and aniline from groundwater in a vertical baffled biofilm reactor.

The challenge of simultaneous removal of nitrobenzene (NB), aniline (AN) and nitrate from groundwater in a single bioreactor is mainly attributed to the persistence of AN to degradation with anoxic denitrification conditions. In this work, simultaneous removal of NB (100 µM), AN (100 µM) and nitrate (1 mM) was achieved within 8 h with a COD/N ratio of 8 in a vertical baffled biofilm reactor (VBBR). By setting DO concentration at 0.4-0.5 mg L-1 to create a micro-aerobic condition, NB removal rate was accelerated without accumulation of AN, and AN could serve as electron donors for denitrification after ring cleavage. High-throughput sequencing showed that biofilm was predominated by denitrifiers (Luteimonas, Planctomyces, Thiobacillus, Thauera and so on) and NB-degrading bacteria (Pseudomonas), and biodiversity varied vertically along the height of the reactor. A dominantly anaerobic pathway for reducing NB to AN was identified by PICRUSt analysis, as the predicted genes involved in aerobic transformation of NB were several magnitudes lower than those in the anaerobic pathway. This study provided a new insight to the role of oxygen in robust bioremediation groundwater contaminated with NB, AN and nitrate.

Rapid generation of genetically engineered T cells for the treatment of virus-related cancers.

Adoptive transfer of T cell receptor (TCR)-engineered T cells targeting viral epitopes represents a promising approach for treating virus-related cancers. However, the efficient identification of epitopes for T cells and the corresponding TCR remains challenging. Here, we report a workflow permitting the rapid generation of human papillomavirus (HPV)-specific TCR-T cells. Six epitopes of viral proteins belonged to HPV16 or HPV18 were predicted to have high affinity to A11:01 according to bioinformatic analysis. Subsequently, CTL induction were performed with these six antigen peptides separately, and antigen-specific T cells were sorted by FACS. TCR clonotypes of these virus-specific T cells were determined using next-generation sequencing. To improve the efficiency of TCRαß pair validation, a lentiviral vector library containing 116 TCR constructs was generated that consisted of predominant TCRs according to TCR repertoire analysis. Later, TCR library transduced T cells were simulated with peptide pool-pulsed antigen-presenting cells, then CD137-positive cells were sorted and subjected to TCR repertoire analysis. The top-hit TCRs and corresponding antigen peptides were deduced and validated. Through this workflow, a TCR targeting the E692-101 of HPV16 was identified. These HPV16-specific TCR-T cells showed high activity towards HPV16-positive human cervical cancer cells in vitro and efficiently repressed tumor growth in a murine model. This study provides a HPV16-specific TCR fitted to the HLA-A11:01 population, and exemplifies an efficient approach that can be applied in large-scale screening of virus-specific TCRs, further encouraging researchers to exploit the therapeutic potential of the TCR-T cell technique in treating virus-related cancers.

Enhanced semi-volatile DNAPL accessibility at sub-boiling temperature during electrical resistance heating in heterogeneous porous media.

Successful remediation of semi-volatile contaminants using electrical resistance heating (ERH) coupled technologies requires a deep understanding of contaminant migration and accessibility, especially with stratigraphic heterogeneity and dense nonaqueous phase liquid (DNAPL) occurrence. Here, we chose nitrobenzene (NB) as a model contaminant of semi-volatile DNAPL and uniquely demonstrated that temperature variation during ERH could induce NB DNAPL migration out of the low permeability zone (LPZ) even below water boiling temperature. When heating the system using alternating current (AC) of 140 V to a temperature range of 50-79 °C, obvious DNAPL migration was visually observed. The upward migration of DNAPL would considerably increase the mass of accessible contaminant by other remediation measures. The downstream cumulative NB mass of 1092 mg in 140 V system raised 56-folds compared to that of 19 mg in the control experiment with only groundwater flow. This migration was mainly attributed to a complex natural convection caused by temperature gradient. Comparing with traditional AC heating, ERH powered by pulsed direct current (PDC-ERH) showed a higher and more uneven heating pattern, resulting in a stronger convection at the same voltage that enhanced the DNAPL migration out of LPZ. These results revealed the importance of natural convection in the ERH process, which could be further optimized to improve the energy efficiency of remediation.

Response and contribution of bacterial and archaeal communities to eutrophication in urban river sediments.

Excessive loading of nitrogen (N) and phosphorus (P) that leads to eutrophication mutually interacts with sediment microbial community. To unravel the microbial community structures and interaction networks in the urban river sediments with the disturbance of N and P loadings, we used high-throughput sequencing analysis and ecological co-occurrence network methods to investigate the responses of diversity and community composition of bacteria and archaea and identify the keystone species in river sediments. The alpha-diversity of archaea significantly decreased with the increased total nitrogen (TN), whereas the operational taxonomic unit (OTU) number of bacteria increased with the increase of available phosphorus (AP). The beta-diversity of archaea and bacteria was more sensitive to N content than P content. The relative abundance of predominant bacterial and archaeal taxa varied differently in terms of different N and P contents. Complexity and connectivity of bacteria and archaea interaction networks showed significant variations with eutrophication, and competition between bacteria became more significant with the increase of N content. The sensitive and the highest connective species (keystone species) were identified for different N and P loadings. Total carbon (TC), water content (WC), microbial alpha-diversity and interaction networks played pivotal roles in the N and P transformation in urban river sediments.

Occurrence of PFASs and its effect on soil bacteria at a fire-training area using PFOS-restricted aqueous film-forming foams.

Fire-training areas (FTAs) are an important source of perfluoroalkyl and polyfluoroalkyl substances (PFASs) pollution. However, the effect of PFASs on soil bacterial communities remains limited. Here, we detected the PFASs in soils ranging from 3.4 to 531.7 µg kg-1 dry weight in seven plots at an FTA where PFOS-restricted aqueous film-forming foams (AFFFs) have been used for 6 years. PFOS was still the dominant homologue despite the restriction by Stockholm Convention, but it was almost three orders of magnitude lower than that in previous studies. PFASs played an important role in shaping the bacterial community, and high levels of PFASs (>100 µg kg-1 dw) reduced the biodiversity and connectivity of soil bacteria. The extreme condition-tolerant bacteria were identified as biomarkers at the FTA. Our study provides valuable insights into the effect of PFOS-restricted AFFFs on soil bacterial communities at the FTA.

Shear creep mechanical properties and damage model of mudstone in open-pit coal mine.

Clarifying the shear creep characteristics of rock and scientifically analyzing its creep deformation law is the key to solving the problem of safe construction and long-term stability analysis of the open-pit coal slope rock mass. Shear creep tests were carried out on mudstone from an open-pit coal mine in Eastern Mongolia to reveal the creep characteristics of mudstone under different normal and shear stresses. Based on the classical Nishihara model, a new composite six-element nonlinear shear creep damage model is established by introducing nonlinear elastomers. Using the least square method, model verification and parameter identification are carried out on the variable test data. At the same time, the influence law of the model parameters on the rock creep deformation is analyzed according to the theoretical curve. The study results showed that the nonlinear shear creeps damage model could better describe the creep characteristics of rock different normal stress and shear stress levels, significantly the non-linear both the strain and time of attenuation creep and accelerated creep. The creep characteristics of the accelerated creep stage described by this model are better than those described by the classical Nishihara model. The model curve is consistent with the changing trend of the experimental data, and the degree of agreement is very high. The correlation coefficients are all above 0.98, which verifies the accuracy and rationality of the model. The influence law of creep parameters is analyzed. The parameters b and c increase nonlinearly with creep. The increase of λ accelerates the process of rock attenuation creep stage; the increase of η10 slows down the progress of rock decay creep stage; with the increase of α, the deformation and creep rate of rock in accelerated creep stage gradually increase. When η2 increases, the deformation in the acceleration stage decreases gradually. The research results can provide important theoretical support for the safe construction and long-term stability analysis of open-pit coal slope rock masses.

Toxicity assessment and microbial response to soil antibiotic exposure: differences between individual and mixed antibiotics.

Increasing amounts of antibiotics are introduced into soils, raising great concerns on their ecotoxicological impacts on the soil environment. This work investigated the individual and joint toxicity of three antibiotics, tetracycline (TC), sulfonamide (SD) and erythromycin (EM) via a whole-cell bioreporter assay. TC, SD and EM in aqueous solution demonstrated cytotoxicity, whilst soil exposure showed genotoxicity, indicating that soil particles possibly affected the bioavailability of antibiotics. Toxicity of soils exposed to TC, SD and EM changed over time, demonstrating cytotoxic effects within 14-d exposure and genotoxic effects after 30 days. Joint toxicity of TC, SD and EM in soils instead showed cytotoxicity, suggesting a synergetic effect. High-throughput sequencing suggested that the soil microbial response to individual antibiotics and their mixtures showed a different pattern. Soil microbial community composition was more sensitive to TC, in which the abundance of Pseudomonas, Pirellula, Subdivision3_genera_incertae_sedis and Gemmata varied significantly. Microbial community functions were significantly shifted by EM amendments, including signal transduction mechanisms, cytoskeleton, cell wall/membrane/envelope biogenesis, transcription, chromatin structure and dynamics, and carbohydrate transport and metabolism. This work contributes to a better understanding of the ecological effects and potential risks of individual and joint antibiotics on the soil environment.

Characterization and identification of microplastics using Raman spectroscopy coupled with multivariate analysis.

The manufacture and use of plastic products have resulted in the release and spread of a massive amount of microplastics. Identifying and quantifying microplastics is challenging due to their small size and complicated composition. Although vibrational spectroscopy has been applied to analyze microplastics, its reliability and throughput are limited by the challenges to distinguish the pending alterations manually and the lack of a spectra-based automated microplastic classification model. The present study applied Raman spectroscopy coupled with multivariate analysis to develop a new and robust analytical method to comprehensively interrogate the spectral profiles of seven microplastic references and real microplastic samples post-exposure to environmental stresses. Besides identifying unique Raman peaks of individual microplastics, their whole spectra were separated by principal component analysis (PCA) and linear discriminant analysis (LDA). Support vector machine (SVM) classification achieved an accuracy rate of over 98% for polypropylene, polyethylene terephthalate, polyvinyl chloride, polycarbonate, polyamide, and over 70% for high-density polyethylene and low-density polyethylene. Real microplastic samples from the breakdown of snack boxes, mineral water bottles, juice bottles, and medicine vials were also matched to their chemical components by SVM with an overall sensitivity, specificity, and accuracy of 98.1%, 99.4%, and 99.1%, respectively. Additionally, post-exposure to environmental stressors, 1D PCA-LDA score plots could still distinguish microplastic type, and the developed SVM classification achieved an accuracy of 96.75% in the real-world scenario. These findings prove Raman spectroscopy coupled with multivariate analysis as an ideal tool to distinguish the types and environmental exposure of microplastics, demonstrating great potential for microplastic automatic detection.