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.

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.

Going with the flow: analysis of population structure reveals high gene flow shaping invasion pattern and inducing range expansion of Mikania micrantha in Asia.

BACKGROUND AND AIMS: Mikania micrantha, a climbing perennial weed of the family Asteraceae, is native to Latin America and is highly invasive in the tropical belt of Asia, Oceania and Australia. This study was framed to investigate the population structure of M. micrantha at a large spatial scale in Asia and to identify how introduction history, evolutionary forces and landscape features influenced the genetic pattern of the species in this region. METHODS: We assessed the genetic diversity and structure of 1052 individuals from 46 populations for 12 microsatellite loci. The spatial pattern of genetic variation was investigated by estimating the relationship between genetic distance and geographical, climatic and landscape resistances hypothesized to influence gene flow between populations. KEY RESULTS: We found high genetic diversity of M. micrantha in this region, as compared with the genetic diversity parameters of other invasive species. Spatial and non-spatial clustering algorithms identified the presence of multiple genetic clusters and admixture between populations. Most of the populations showed heterozygote deficiency, primarily due to inbreeding, and the founder populations showed evidence of a genetic bottleneck. Persistent gene flow throughout the invasive range caused low genetic differentiation among populations and provided beneficial genetic variation to the marginal populations in a heterogeneous environment. Environmental suitability was found to buffer the detrimental effects of inbreeding at the leading edge of range expansion. Both linear and non-linear regression models demonstrated a weak relationship between genetic distance and geographical distance, as well as bioclimatic variables and environmental resistance surfaces. CONCLUSIONS: These findings provide evidence that extensive gene flow and admixture between populations have influenced the current genetic pattern of M. micrantha in this region. High gene flow across the invaded landscape may facilitate adaptation, establishment and long-term persistence of the population, thereby indicating the range expansion ability of the species.

Long-term oil contamination increases deterministic assembly processes in soil microbes.

The mechanisms that drive microbial turnover in time and space have received considerable attention but remain unclear, especially for situations with anthropogenic perturbation. To understand the impact of long-term oil contamination on microbial spatial turnover, 100 soil samples were taken from five oil exploration fields located in different geographic regions across China. The microbial functional diversity was analyzed with a high-throughput functional gene array, GeoChip. Our results indicated that soil microbial α-diversity (richness and Shannon diversity index) decreased significantly with contamination. All contaminated and uncontaminated samples exhibited significant spatial autocorrelation between microbial community similarity and spatial distance, as described by a distance-decay relationship (DDR). However, long-term oil exposure flattened the slopes of the DDRs of all of the functional genes and each functional group involved in C/N/P/S cycling, particularly of those involved in contaminant degradation. The relative importance of deterministic and stochastic processes in microbial assembly was determined. The decrease in microbial spatial turnover with long-term oil contamination was coupled with an increase in the proportion of deterministic processes that structured microbial assembly based on null model analysis. The results indicated long-term oil contamination significantly affects soil microbial community spatial structure by acting as an environmental filter to decrease the regional differences distinguishing soil microbial communities.

Biodegradation of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) with plant and nutrients and their effects on the microbial ecological kinetics.

Four pilot-scale test mesocosms were conducted for the remediation of organochlorine pesticides (OCPs)-contaminated aged soil. The results indicate that the effects on degradation of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were in the following order: nutrients/plant bioaugmentation (81.18 % for HCHs; 85.4 % for DDTs) > nutrients bioaugmentation > plant bioaugmentation > only adding water > control, and nutrients/plant bioaugmentation greatly enhanced the degradation of HCHs (81.18 %) and DDTs (85.4 %). The bacterial community structure, diversity and composition were assessed by 454-pyrosequencing of 16S recombinant RNA (rRNA), whereas the abundance of linA gene was determined by quantitative polymerase chain reaction. Distinct differences in bacterial community composition, structure, and diversity were a function of remediation procedure. Predictability of HCH/DDT degradation in soils was also investigated. A positive correlation between linA gene abundance and the removal ratio of HCHs was indicated by correlation analyses. A similar relationship was also confirmed between the degradation of HCHs/DDTs and the abundance of some assemblages (Gammaproteobacteria and Flavobacteria). Our results offer microbial ecological insight into the degradation of HCHs and DDTs in aged contaminated soil, which is helpful for the intensification of bioremediation through modifying plant-microbe patterns, and cessation of costly and time-consuming assays.

Use of a whole-cell bioreporter, Acinetobacter baylyi, to estimate the genotoxicity and bioavailability of chromium(VI)-contaminated soils.

A whole-cell bioreporter, Acinetobacter baylyi ADPWH_recA, was used to estimate the genotoxicity and bioavailability of chromium (VI) [Cr(VI)] in contaminated soils. Upon direct exposure to pre-sonicated soil samples, ADPWH_recA gave the highest response to the genotoxicity of Cr(VI) within 5 h with a detection limit of 2 µM Cr(VI). Investigations on sites contaminated with Cr(VI) revealed that soil-associated Cr(VI) was bioavailable to the bioreporter although it could not be extracted into the aqueous phase. The physical and chemical properties of soil might influence the bioavailability of Cr(VI), and higher genotoxicity was found in soils with a lower pH. This whole cell bioreporter approach makes it feasible to evaluate the bioavailability and genotoxicity of Cr(VI)-contaminated soils to uncover their potential impact on human health.

Innovative slow-release organic carbon-source material for groundwater in situ denitrification.

Slow-release organic carbon-source (SOC) material, a new kind of electron donor for in situ groundwater denitrification, was prepared and evaluated in this study. With starch as a biologically utilized carbon source and polyvinyl alcohol (PVA) as a frame, this material performed controllable carbon release rates and demonstrated stable behaviour during the simulated denitrification process. Raman spectrum analysis showed that the PVA skeleton formed cross-linking network structures for hydrogen-bonded water molecules reset in low temperatures, and the starchy molecules filled in the interspace of the skeleton to form a two-phase interlocking/disperse phase structure. In a static system, carbon release processes followed the Fickian law with (1.294-6.560)×10(-3) mg g(-1) s(-1/2) as the release coefficient. Under domestication and in situ groundwater simulation conditions, SOC material played a favourable role during denitrification, with 1.049±0.165 as an average carbon-nitrogen ratio. The denitrification process followed the law of zero-order kinetics, while the dynamics parameter kN was 0.563-8.753 gN m(-3) d(-1). Generally, SOC material was suggested to be a potential carbon source (electron donor) suitable for in situ groundwater denitrification.

Structure and mass transportation model of slow-release organic carbon-source material for groundwater in situ denitrification.

Based on the theories of organic polymer and chemical kinetics, the structure and mass transportation model of slow-release organic carbon-source (SOC) material was developed in this study to reveal and predict the carbon release mechanisms of polymer carbon source, which was feasible for in situ denitrification in nitrate-contaminated groundwater. Composed of polyvinyl alcohol (PVA) and starch, the SOC material formed the interlocking/disperse-phase structure. PVA performed as continuous phase and skeleton, whereas the starch or cellulose behaved as release component. Carbon release process was identified in two stages: solid-phase (inner) and interface (gel layer) diffusion. Solid-phase diffusion was affected by material porous medium parameters, for example, distance between the crosslinking points and starch free energy. The interface diffusion depended mostly on the groundwater dynamics and interface energy distribution. The interface diffusion was found as the limiting step of carbon release process, and the carbon release coefficient corresponded to kD,I as static coefficient and kC,I as dynamic coefficient. As the key indicator to evaluate carbon release capacity, kD,I and kC,I represented appropriate boundary conditions and interface properties. Sensitivity analysis showed that the key parameters of the carbon release model were the distance between the crosslinking points and the free energy of polymer, influenced by regulation of preparation technique, raw material composition and additive dosage.

In situ ZnO nanowire growth to promote the PVDF piezo phase and the ZnO-PVDF hybrid self-rectified nanogenerator as a touch sensor.

A PVDF-ZnO nanowires (NWs) hybrid generator (PZHG) was designed. A simple, cost effective method to produce the PVDF ß phase by nano force is introduced. With the ZnO NWs growing, the in situ nano extension force promotes the phase change. A theoretical analysis of the ZnO NWs acting as a self-rectifier of the nano generator is established. The ZnO NWs acted as a self-adjustment diode to control the current output of the PZHG by piezo-electric and semi-conductive effects. Based on the self-controllability of the piezoelectric output, three kinds of finger touching are distinguished by the output performances of the PZHG, which is applicable to an LCD touch pad.

Unraveling soil geochemical, geophysical, and microbial determinants of the vertical distribution of organic phosphorus pesticide pollutants.

Pesticide contamination has emerged as a global threat to humans. Here, we investigate the soil distribution pattern of organic phosphorus pesticide contamination at a pesticide manufacturing site in northern China, exploring their relationships with soil properties and microbial communities. The concentrations of four organic phosphorus pesticides (i.e., phorate, terbuthion, fenitrothion, and parathion) decreased substantially with soil depths from the surface down to 2 m. However, terbuthion, fenitrothion, and parathion had second-peak concentrations at a depth of 8 m. The concentrations of those organic phosphorus pesticides were negatively correlated with soil water content, but positively correlated with sulfide, pH, and total phosphorus. The distribution patterns of organic phosphorus pesticides closely aligned with that of soil organic matter and clay minerals, especially in the presence of montmorillonite, kaolinite, and chlorite. Various bacterial genera known to degrade organic phosphorus pesticides, such as Flavobacterium, Bacillus, Acinetobacter, Lactobacillus, Pseudomonas, Sphingomonas, and Thiobacillus, were correlated with these pesticides. Since these genera were among the top 50 abundant genera in our samples, they might play a significant role in the degradation of organic phosphorus pesticides. Together, this study unveils previously unrecognized pesticide-soil-microbe interactions, thus providing an important knowledge basis for environmental remediation strategies.

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.

Direct current driven persulfate delivery and activation for heterogeneous porous media remediation: Coupling effects of electric-thermal-chemical-flow fields.

Direct current (DC) has promising potential for persulfate delivery and activation in heterogeneous site remediation, yet requires deeper understanding. Here, we investigated the efficiency of DC for persulfate delivery and activation and compared with alternating current (AC). While AC electric field only influenced persulfate fate by Joule heating effect, DC electric field induced electrokinetic migration of persulfate and contaminants, as well as promoted persulfate activation with Joule heating and electrochemical reactions. DC system achieved 95 % MCB removal which was 3.1 times of that in AC system using the same voltage input (60 V) with a velocity of 0.5 m/d. When the applied DC voltage increased from 20 V to 60 V (0.5-1.5 V/cm), persulfate activation pathway changed from electrode reactions to the coupled activation pathways of electrode, chemical and heat reactions, thus resulting in increasing MCB removal efficiency from 57 % (20 V) to 95 % (40 V and 60 V). The energy consumption with 40 V (11.6 kWh/g) was 2.6 times of that using 20 V (4.4 kWh/g), and dramatically increased to 11.7 times with 60 V (50.2 kWh/g). This study provides a new perspective on improving the efficiency of persulfate delivery and activation in heterogeneous sites remediation using DC-driven system.

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 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.

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.

Long term impact of electrical resistance heating on soil bacterial community based on a field test.

Thermal remediation is an effective technology for organic contaminant remediation. However, the application of thermal remediation may have negative effects on soil properties and ecological functions, which requires further investigation. Based on a pilot test of electrical resistance heating remediation (ERH), soil samples were collected at different locations after heating for 116 days. Most soil physicochemical properties were less affected by the heating temperature difference. Application of high temperature increased microbial abundance but inhibited alpha diversity of the bacterial community. More significant changes in microbial communities were observed at temperatures above 60 °C. The genera mainly affected by heating temperature included Flavobacteria, Brockia, and S085, while the increase in temperature also inhibited the abundance of nitrochlorobenzene functional genes. At 140 days after the end of the pilot test, the bacterial community affected by thermal remediation could recover effectively, and the recovery of the bacterial community was not affected by temperature difference during the heating period. This study provides valuable field evidence of the long term impact of soil ERH treatment on soil properties and microbial communities, and provides further references for optimization of remediation performance with coupled technologies.

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.

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.

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.

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.