Exploring the underlying mechanisms of enteritis impact on golden pompano (Trachinotus ovatus) through multi-omics analysis.

Enteritis posed a significant health challenge to golden pompano (Trachinotus ovatus) populations. In this research, a comprehensive multi-omics strategy was implemented to elucidate the pathogenesis of enteritis by comparing both healthy and affected golden pompano. Histologically, enteritis was characterized by villi adhesion and increased clustering after inflammation. Analysis of the intestinal microbiota revealed a significant increase (P < 0.05) in the abundance of specific bacterial strains, including Photobacterium and Salinivibrio, in diseased fish compared to the healthy group. Metabolomic analysis identified 5479 altered metabolites, with significant impacts on terpenoid and polyketide metabolism, as well as lipid metabolism (P < 0.05). Additionally, the concentrations of several compounds such as calcitetrol, vitamin D2, arachidonic acid, and linoleic acid were significantly reduced in the intestines of diseased fish post-enteritis (P < 0.05), with the detection of harmful substances such as Efonidipine. In transcriptomic profiling, enteritis induced 68 upregulated and 73 downregulated genes, predominantly affecting steroid hormone receptor activity (P < 0.05). KEGG pathway enrichment analysis highlighted upregulation of SQLE and CYP51 in steroidogenesis, while the HSV-1 associated MHC1 gene exhibited significant downregulation. Integration of multi-omics results suggested a potential pathogenic mechanism: enteritis may have resulted from concurrent infection of harmful bacteria, specifically Photobacterium and Salinivibrio, along with HSV-1. Efonidipine production within the intestinal tract may have blocked certain calcium ion channels, leading to downregulation of MHC1 gene expression and reduced extracellular immune recognition. Upregulation of SQLE and CYP51 genes stimulated steroid hormone synthesis within cells, which, upon binding to G protein-coupled receptors, influenced calcium ion transport, inhibited immune activation reactions, and further reduced intracellular synthesis of anti-inflammatory substances like arachidonic acid. Ultimately, this cascade led to inflammation progression, weakened intestinal peristalsis, and villi adhesion. This study utilized multi-level omics detection to investigate the pathological symptoms of enteritis and proposed a plausible pathogenic mechanism, providing innovative insights into enteritis verification and treatment in offshore cage culture of golden pompano.

pH-Activatable copper-axitinib coordinated multifunctional nanoparticles for synergistic chemo-chemodynamic therapy against aggressive cancers.

Chemodynamic therapy (CDT) is an emerging oncological treatment that eliminates tumor cells by generating lethal hydroxyl radicals (˙OH) through Fenton or Fenton-like reactions within tumors. However, the effectiveness of CDT is limited by the overexpression of glutathione (GSH) and low reaction efficiency in the tumor microenvironment (TME). To address these challenges and enhance tumor treatment, we developed a novel pH-activatable metal ion-drug coordinated nanoparticle (Cu-AXB NPs) system, incorporating a CDT agent (Cu2+) and a chemotherapeutic agent (axitinib, AXB). The obtained Cu-AXB NPs exhibited exceptional characteristics, including ultrahigh drug loading capacity (87.55%) and an average size of 180 nm. These nanoparticles also demonstrated excellent plasma stability and pH-responsive drug release, enabling prolonged circulation in the bloodstream and targeted therapy at weakly acidic tumor sites. Upon release, AXB acted as a chemotherapeutic agent, effectively eliminating tumor cells, while Cu2+ ions were reduced to Cu+ by GSH, further generating toxic ˙OH with hydrogen peroxide (H2O2) for CDT through a Fenton-like reaction. Additionally, the Cu-AXB NPs efficiently disrupted the copper metabolic balance and increased the intracellular Cu content, further amplifying the therapeutic impact of CDT. In vitro studies assessing cytotoxicity and apoptosis confirmed the superior tumor cell-killing efficacy of the Cu-AXB NPs. This enhanced efficacy can be attributed to the synergistic effect of CDT and chemotherapy. Moreover, the Cu-AXB NPs exhibited excellent tumor targeting capabilities, resulting in significant tumor inhibition (77.53% inhibition) while maintaining favorable biocompatibility in tumor-bearing mice. In conclusion, this study presents a promising and safe strategy for cancer therapy by combining CDT with chemotherapy, offering a potential breakthrough in the field of oncology.

Feasibility of soil oxidation-reduction potential in judging shear behaviour of hydrocarbon-contaminated soil.

This study investigates the indicative role of oxidation-reduction potential (ORP) and pH of hydrocarbon-contaminated soils on their shear characteristics, contributing to safer and more efficient ex-situ remediation and management processes. The presence of hydrocarbons alters the soil's shear strength by affecting the hydration shell thickness, fluid's dielectric properties, and ion/electron exchange, as well as the soil's electrochemical force, which in turn affects the ORP and pH. The relationship between hydrocarbon concentrations in contaminated soils (0.1-15%) and corresponding ORP/pH values could be fitted linearly with a good correlation coefficient r (0.978), highlighting the potential of ORP/pH as an indicator for pollutant occurrence. Furthermore, the relationships between ORP/pH and shear strength, as tested in our study and obtained after processing from relevant literature sources, exhibited a strong fit (r = 0.976-0.995). The Mohr-Coulomb criterion modified using the ORP/pH parameter was established, which could improve the fitting effect of these relationships (r = 0.988-0.996), verifying the reliability of the novel criterion and application feasibility of ORP/pH. In future research, this modified criterion can be employed to conveniently assess the shear strength of contaminated soil by considering the shear behaviour of virgin soil and the ORP/pH values of the contaminated soil.

Environmental, economic, and social sustainability assessment: A case of using contaminated tailings stabilized by waste-based geopolymer as road base.

Contaminated tailings, e.g., iron tailings, could be stabilized by low-carbon geopolymers for recycling as road base, but the sustainability has yet to be evaluated comprehensively. This study developed a sustainable framework from the life cycle perspective, consisting of quantitative indicators in environment, society, and economy, to assess five stabilization cases (i.e., M1, M2, C1, C2, and cement). Moreover, a modified AHP (Analytic Hierarchy Process)-CRITIC (CRiteria Importance Through Inter-criteria Correlation)-TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) model was applied to select the most sustainable stabilization method. The sustainability scores of four cases using geopolymers were higher than that of the cement case (0.22), with C2 (0.75), C1 (0.64), M1 (0.56), and M2 (0.54), respectively. Sensitivity analysis confirmed that the assessment results were relatively stable, especially when the subjective weight of the economy was not the highest (the cement counterpart had economic advantages). This study constituted a novel approach to complement the selection of sustainable stabilization cases, bridging the gap of focusing exclusively on green stabilization performance.

In situ rearranged multifunctional lipid nanoparticles via synergistic potentiation for oral insulin delivery.

Oral administration of therapeutic peptides/proteins (TPPs) is confronted with multiple gastrointestinal (GI) barriers such as mucus and intestinal epithelium, and the first-pass metabolism in the liver is also responsible for low bioavailability. In situ rearranged multifunctional lipid nanoparticles (LNs) were developed to overcome these obstacles via synergistic potentiation for oral insulin delivery. After the reverse micelles of insulin (RMI) containing functional components were gavaged, LNs formed in situ under the hydration effect of GI fluid. The nearly electroneutral surface generated by the rearrangement of sodium deoxycholate (SDC) and chitosan (CS) on the reverse micelle core facilitated LNs (RMI@SDC@SB12-CS) to overcome mucus barrier and the sulfobetaine 12 (SB12) modification further promoted epithelial uptake of LNs. Subsequently, chylomicron-like particles formed by the lipid core in the intestinal epithelium were easily transported to the lymphatic circulation and then into the systemic circulation, thus avoiding hepatic first-pass metabolism. Eventually, RMI@SDC@SB12-CS achieved a high pharmacological bioavailability of 13.7% in diabetic rats. In conclusion, this study provides a versatile platform for enhanced oral insulin delivery.

Self-Assembly of a Linear-Dendritic Polymer Containing Cisplatin and Norcantharidin into Raspberry-like Multimicelle Clusters for the Efficient Chemotherapy of Liver Cancer.

Combination chemotherapy has been proved to be an effective strategy in the clinic, and nanoformulations have drawn much attention in the field of drug delivery. However, conventional nanocarriers suffer from shortcomings such as inefficient coloading and undesired molar ratios of the combined drugs, preleakage of cargos during systemic circulation, and lack of cancer-selective drug release. To achieve tumor-specific codelivery of cisplatin (CDDP) and norcantharidin (NCTD) for synergistic treatment of liver cancer, a novel linear-dendritic polymer, termed as G1(PPDC)x, was designed and synthesized, where a prodrug consisting of cisplatin (CDDP) and norcantharidin (NCTD) was conjugated to PEG2000 via ester bonds to fabricate linear polymer-drug conjugates, and the conjugates were subsequently grafted to the terminal hydroxyls of a dendritic polycarbonate core. Benefiting from the hydrogen bond interactions, G1(PPDC)x could spontaneously self-assemble into a unique type of raspberry-like multimicelle clusters in solution (G1(PPDC)x-PMs). G1(PPDC)x-PMs possessed an optimal synergistic ratio of CDDP and NCTD, without obvious premature release or disassembly in biological environments. Intriguingly, upon extravasation into the interstitial tumor tissues, G1(PPDC)x-PMs (132 nm in diameter) could disassemble and reassemble into smaller micelles (40 nm in diameter) in response to the mildly acidic tumor microenvironment, which would enhance the deep tumor penetration and cellular accumulation of drugs. In vivo delivery of G1(PPDC)x-PMs led to a significantly prolonged blood circulation half-life, which is beneficial to achieve sufficient tumor accumulation through the enhanced permeability and retention (EPR) effect. G1(PPDC)x-PMs displayed the best antitumor activity in H22 tumor-bearing mice with a tumor inhibition rate of 78.87%. Meanwhile, G1(PPDC)x-PMs alleviated both myelosuppression toxicities of CDDP and vascular irritation of NCTD. Our results demonstrated that G1(PPDC)x-PMs could serve as an effective drug delivery system for codelivery of CDDP and NCTD to treat liver cancer efficiently.

Study on the effect of landfill gas on aerobic municipal solid waste degradation: Lab-scale model and tests.

Aeration is of great importance in landfill remediation. However, most existing studies on aerobic waste degradation ignore the presence of landfill gases. In this study, gas characteristics during aerobic waste degradation in the presence of landfill gas in lab-scale lysimeters were investigated. Oxygen (O2) was intermittently injected into municipal solid waste. Changes in the gas concentration and reaction rate of methane (CH4), carbon dioxide (CO2), and O2 during the reaction process were monitored and calculated. The results showed that all reactions, including aerobic degradation, CH4 oxidation, and anaerobic waste degradation, occurred simultaneously during landfill aeration. The maximum O2 consumption rate was 0.013 mol day-1 kg-1 dry waste. CH4 production was stimulated after the O2 content was insufficient to sustain the aerobic environment. Higher CH4 production was likely attributed to the remaining substrate and biomass from dead aerobic microorganisms decomposed by growing anaerobic microorganisms. Based on the biochemical reaction and principle of mass conservation, a gas balance model during waste aeration was established to analyze the proportions of aerobic waste degradation, CH4 oxidation, and anaerobic waste degradation. The CH4 oxidation reaction was more advantageous than the aerobic waste degradation reaction during aeration. With an increase in gas injection times, the anaerobic reaction gradually weakened. The maximum proportion of CH4 oxidation reaction could achieve at 21.4 % during aeration, which is of great significance for the waste degradation reaction. The maximum proportion of aerobic waste degradation and the minimum proportion of anaerobic waste degradation were approximately 16.0 % and 74.2 %, respectively. The results show that landfill gas should be considered in the progress of landfill aeration. This study provides a novel approach for calculating the proportion of reactions during landfill aeration, which deepens the understanding of the reaction process and contributes to the design of aerobic landfill projects.

Impact of simulating real microplastics on toluene removal from contaminated soil using thermally enhanced air injection.

This paper investigated the impacts of various real microplastics (MPs), i.e., polyethylene (PE) and polyethylene terephthalate (PET) with different sizes (1000-2000 and 100-200 µm) and different dosages (0.5 and 5% on a dry weight basis), on the toluene removal during the thermally enhanced air injection treatment. First, microscopic tests were carried out to determine the MPs' microstructure and behavior. The PE was mainly a small block, and PET appeared filamentous and sheeted with a larger slenderness ratio. Second, the interactions between MPs and toluene-contaminated soils were revealed by batch adsorption equilibrium experiments and low-field magnetic resonance. The morphological differences and dosage of the MPs impacted soils' total porosity (variation range: 39.2-42.7%) and proportion of the main pores (2-200 µm). Third, the toluene removal during the air injection consisted of compaction, rapid growth, rapid reduction, and tailing stages, and the MPs were regarded as an emerging solid state to affect these removal stages. The final cumulative toluene concentrations of soil-PET mixtures were influenced by total porosity, and those of soil-PE mixtures were controlled by total porosity (influence weight: 0.67) and adsorption capacity (influence weight: 0.33); meanwhile, a self-built comprehensive coefficient of MPs can reflect the relationship between them and cumulative concentrations (correlation coefficient: 0.783).

Thermal desorption optimization for the remediation of hydrocarbon-contaminated soils by a self-built sustainability evaluation tool.

Current thermal desorption practices of hydrocarbon-contaminated soils focus on remediation efficiency and cost, with little systematic assessment of the reuse value of treated soils. This study evaluated various integrated indices of treatment cost and reuse of treated soils at three desorption temperatures. Various typical engineering and ecological characteristics closely related to soil reusability were selected to analyze the changes in various treated soils, including shear strength, Atterberg limits, particle size distribution, permeability, soil carbon, and soil biomass. A sustainability evaluation tool was developed for the greener disposal of hazardous soils considering both the treatment cost and reuse indices. Such an evaluation led to the conclusion that the contaminated soils treated at 350 °C generated the highest soil reusability with an excellent remediation efficiency. The sensitivity analysis confirmed that the tool had better stability in a common situation where the weight of the remediation cost was heavier than the soil reusability. Meanwhile, published data were input into the tool to validate its applicability under different scenarios. The results were consistent with the qualitative assessment of the literature. The tool can quantitatively select a more sustainable desorption method for the disposal and reuse of hazardous soils.

Candidate sex-associated gene identification in Trachinotus ovatus (Carangidae) using an integrated SLAF-seq and bulked segregant analysis approach.

It is difficult to distinguish the sexes of Trachinotus ovatus based on appearance, and little data about sex-determining genes are available for this species. Here, we generated 200 F2 individuals using the parents R404 and R403. DNA samples were collected from 50 individuals of each sex and aggregated into sex-specific DNA pools. Specific-locus amplified fragment sequencing was integrated with bulked segregant analysis to detect candidate sex-associated genes. Approximately 3,153,153 high-quality single-nucleotide polymorphism (SNP) markers and 135,363 high-quality insertion-deletion (Indel) markers were generated. Six candidate regions within chromosome 14, encompassing 132 candidate genes, were identified as closely related to sex. Based on annotations, six genes (EVM0019817, EVM0004192, EVM0001445, EVM0005260, EVM0014734, and EVM0009626) were predicted to be closely associated with sex. These results present an efficient genetic mapping approach that lays a foundation for molecular sex discrimination in T. ovatus.

A fenestrated persistent primitive hypoglossal artery harboring a ruptured aneurysm: A case report.

RATIONALE: Persistent primitive hypoglossal artery (PPHA) is a rare and permanent carotid-vertebrobasilar anastomoses. Patients with PPHA usually have higher changes of developing intracranial aneurysms due the high intracranial hemodynamics. Although cases of PPHA alone and PPHA with aneurysms have been reported in literature, cases of fenestrated PPHA harboring a ruptured aneurysm have seldomly be reported in literature. We present a rare occurrence of a fenestrated PPHA harboring a reputed aneurysm. PATIENTS CONCERNS: A 43-year-old woman was presented with a sudden-onset severe headache and nausea. DIAGNOSIS: Computerized tomography scan showed third, fourth, and bilateral ventricular hemorrhages. Computed tomographic angiogram showed a PPHA with fenestration malformation and a cystic protrusion consistent with an aneurysm. INTERVENTION: The patient underwent a successful stent-assisted coil embolization via the trans-arterial route under general anesthesia. OUTCOMES: Two years follow-up revealed no recurrence of her symptomatology and she is currently well and go about her normal daily life. CONCLUSION: Fenestrated PPHAs harboring aneurysms may be more prone to rupture because of the fenestration and connective tissue weakness of the artery as well as changes in hemodynamics of the already malformed and weak artery.

New methods for quantification of Fenton's reagent addition based on aged sludge indicators to improve filterability.

Fenton oxidation can effectively improve the dewaterability of aged sludge. Quantification of the addition of optimal reagents is central to the conditioning and dewatering of aged sludge. Improving the accuracy of quantification is significant to promote cost effectiveness. The effects of reagent addition and the mechanism governing the improved filterability of the aged sludge need to be understood uniformly. In this study, the optimal reagent additions have been determined using the response surface method (RSM) for five out of the eight aged sludges that were investigated. The physicochemical characteristics of eight aged sludges, including the extracellular polymer substance, undissolved organic matter, and suspension structure network, were investigated. Meanwhile, a comprehensive correlation analysis of critical indicators was conducted to investigate the interactions among the properties of the aged sludge. The effects of these interactions on the conditioning and filtration processes were examined, and a unified understanding of the combination of factors affecting the optimal reagent addition was obtained. The key factors were aggregate size, dewatering extent, yield stress, and organic substance content. Based on these results, a new reagent addition quantification method was developed along with an empirical model of the relationship between physicochemical properties and the economically optimal reagent addition.

Evaluation of the effectiveness of VOC-contaminated soil preparation based on AHP-CRITIC-TOPSIS model.

Currently, several methods have been adopted for the laboratory preparation of artificial volatile organic compound (VOC) contaminated soils (VCSs). However, it remains unclear whether the prepared contaminated soils are homogenous. In this study, two representative VOCs, toluene and perchloroethylene, were separately mixed with a kaolin-based soil using six preparation methods. Thereafter, the homogeneity and recovery of the contaminated kaolin prepared using these methods were determined and analyzed. The six procedures were quantitatively assessed according to the comprehensive evaluation mathematical model (AHP-CRITIC-TOPSIS), and the final score order of the different procedures was: A > C > E > B > F > D. Additionally, the qualitative evaluation of the procedures was performed based on the phase transformation and mass transfer during the mixing processes. Based on these discussions, method A, which was considered to be optimal, was then adopted for further investigations with various natural soils. The results showed that this optimal method could be applied to natural soils and revealed that the adsorption-related characteristics of natural soils, including total organic carbon, specific surface area, pore volume, pH, plastic limit, particle size, and mineral composition, influenced the homogeneity and recovery through mass transfer. In addition, it was also observed that the chemical properties of VOCs, including molecular structure, vapor pressure, and the octanol/water partition coefficient, could also affect the effectiveness of sample recovery. Through this study, researchers can prepare VCSs with excellent homogeneity and low loss rates to conduct standardized tests for technology development.

Severe autoimmune-mediated thrombocytopenia in an elderly woman.

The efficacy of immunotherapies that use antibodies to block programmed cell death 1 (PD-1) has been extensively investigated for lung cancer. Along with reactivation of the patient's immune response to tumour cells, immune-related adverse effects with anti-PD1 therapy have been reported. We report an 80-year-old woman who had suffered from a primary lung adenocarcinoma pre-treated with pembrolizumab and was admitted to our hospital with serious autoimmune-mediated thrombocytopenia induced by pembrolizumab.

Adsorption of toluene on various natural soils: Influences of soil properties, mechanisms, and model.

This study investigated toluene adsorption on natural soils. The linear partition model was found to represent the adsorption isotherm well (R2 = 0.958-0.994), compared with the Freundlich model (R2 = 0.901-0.991). Therefore, the coefficient, Kd, of the linear model indicated the adsorption capacity of soils A to F. Traditionally, Kd and the total organic carbon (TOC) content have a good linear relationship. However, this relationship was weak (correlation coefficient (r) = 0.689) when TOC values (8.43-12.9 mg/g) were low and close. To correct this deviation, this study investigated the influences of physicochemical properties, such as special surface area, mineral composition, functional groups, pH, and potentials. As soils B and C consisted of a large amount of active clayey minerals (69.4% kaolinite and 79.3% nacrite, respectively) and rich functional groups, they demonstrated the strongest adsorption capacity. Additionally, the r for pH-Kd, zeta potential-Kd, and redox potential-Kd were high, at 0.806, 0.914, and 0.932, respectively. To explore adsorption mechanisms, the adsorption thermodynamic parameter (enthalpy) was used initially to determine the forces. Combined with the analysis of soil properties, the mechanisms identified were hydrophobic interaction and hydrogen-pi bonding, involving co-adsorption with water molecules. Based on all studies, the properties were quantified and simplified by the plastic limit (PL), and TOC was simplified by soil organic matter (SOM). Then, PL and SOM were weighted by the entropy-weight method to obtain the determination factor, DF, a logarithmic parameter to replace TOC. Finally, a new model describing toluene adsorption on natural soils was established and expressed as Kd = 4.80 + 3.53DF. This new model had significantly improved the correlation between Kd and TOC (r = 0.933) and expanded the engineering adaptability.

CTRP3 ameliorates cerulein-induced severe acute pancreatitis in mice via SIRT1/NF-κB/p53 axis.

Severe acute pancreatitis (SAP) is a common and life-threatening clinical acute abdominal disease. C1q/tumor necrosis factor-related protein 3 (CTRP3), a novel paralog of adiponectin, has been identified as a crucial regulator in multiple types of inflammatory disorders. However, the biological role of CTRP3 in SAP remains poorly understood. The present study aimed to characterize the role of CTRP3 in SAP and illuminate the potential mechanisms involved. In the current study, SAP mouse models were induced by seven hourly intraperitoneal injection of cerulein (50 µg/kg) and an immediate intraperitoneal injection of lipopolysaccharide (10 mg/kg) after the last cerulein administration. Histological examination and serological analysis demonstrated that SAP mouse models were successfully established. Herein, we found that CTRP3 expression was significantly decreased in the pancreatic tissues of SAP mice compared with normal control mice. Furthermore, we explored the effects of CTRP3 rescue in SAP mice and discovered that CTRP3 overexpression attenuated pathological lesions, inhibited inflammatory mediator release and repressed acinar cell apoptosis. Notably, mechanistic studies revealed that CTRP3 overexpression suppressed NF-κB p65 phosphorylation and p53 acetylation to alleviate cerulein-induced SAP in mouse models through activation of silent information regulator 1 (SIRT1), a nicotinamide adenine dinucleotide-dependent protein deacetylase. Collectively, our data indicate that CTRP3 may exert its protective effects in SAP mice via regulation of SIRT1-mediated NF-κB and p53 signaling pathways, implying a promising therapeutic strategy against SAP.

A case report of unusual cavity presentation of pulmonary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.

RATIONALE: The common CT scan findings of pulmonary MZBL of MALT type include airspace consolidation, nodules and ground-glass opacity. But, to our knowledge, the present case is the first report of a cavity presentation of pulmonary MZBL of MALT type. PATIENT CONCERNS: The patient gives his consent and authorizes the photographs featuring his likeness to be published. DIAGNOSES: This patient was diagnosed as pulmonary MZBL of MALT type by pathology, immunohistochemistry, and gene rearrangement. INTERVENTIONS: The patient was treated with CHOP (cyclophosphamide, adriamycin, vincristine and prednisone) chemotherapy for twice and antibiotics. OUTCOMES: He is being followed up for one year, with slight progress in pulmonary MZBL of MALT. LESSONS: This case highlights the need to be suspicious of MZBL of MALT type, when a radiographic image shows cavity lesion. We should consider whether the diagnosis is correct, when the patient's treatment is not effective.

Effect of carbonation on leachability, strength and microstructural characteristics of KMP binder stabilized Zn and Pb contaminated soils.

This study presents a systematic investigation of effects of carbonation on the contaminant leachability and unconfined compressive strength of KMP stabilized contaminated soils. A field soil spiked with Zn and Pb individually and together is stabilized using a new KMP additive under standard curing conditions and also with carbonation. The KMP additive is composed of oxalic acid-activated phosphate rock, monopotassium phosphate and reactive magnesia. The stabilized soils are tested for acid neutralization capacity, toxic characteristics leaching characteristics, contaminant speciation and unconfined compression strength. X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy analyses are performed to assess reaction products. The results demonstrate that carbonation increases both acid buffer capacity index and unconfined compressive strength, but decreases leachability of KMP stabilized soils. These results are interpreted based on the changes in chemical speciation of Zn and Pb and also stability and solubility of the reaction products (metal phosphates and carbonates) formed in the soils. Overall, this study demonstrates that carbonation has positive effects on leachability and strength of the KMP stabilized soils.

Effects of freeze-thaw on characteristics of new KMP binder stabilized Zn- and Pb-contaminated soils.

For viable and sustainable reuse of solidified/stabilized heavy metal-contaminated soils as roadway subgrade materials, long-term durability of these soils should be ensured. A new binder, KMP, has been developed for solidifying/stabilizing soils contaminated with high concentrations of heavy metals. However, the effects of long-term extreme weather conditions including freeze and thaw on the leachability and strength of the KMP stabilized contaminated soils have not been investigated. This study presents a systematic investigation on the impacts of freeze-thaw cycle on leachability, strength, and microstructural characteristics of the KMP stabilized soils spiked with Zn and Pb individually and together. For comparison purpose, Portland cement is also tested as a conventional binder. Several series of tests are conducted including the toxicity characteristic leaching procedure (TCLP), modified European Community Bureau of Reference (BCR) sequential extraction procedure, unconfined compression test (UCT), and mercury intrusion porosimetry (MIP). The results demonstrate that the freeze-thaw cycles have much less impact on the leachability and strength of the KMP stabilized soils as compared to the PC stabilized soils. After the freeze-thaw cycle tests, the KMP stabilized soils display much lower leachability, mass loss, and strength loss. These results are assessed based on the chemical speciation of Zn and Pb, and pore size distribution of the soils. Overall, this study demonstrates that the KMP stabilized heavy metal-contaminated soils perform well under the freeze-thaw conditions.

New phosphate-based binder for stabilization of soils contaminated with heavy metals: leaching, strength and microstructure characterization.

Cement stabilization is used extensively to remediate soils contaminated with heavy metals. However, previous studies suggest that the elevated zinc (Zn) and lead (Pb) concentrations in the contaminated soils would substantially retard the cement hydration, leading to the deterioration of the performance of cement stabilized soils. This study presents a new binder, KMP, composed of oxalic acid-activated phosphate rock, monopotassium phosphate and reactive magnesia. The effectiveness of stabilization using this binder is investigated on soils spiked with Zn and Pb, individually and together. Several series of tests are conducted including toxicity characteristic leaching (TCLP), ecotoxicity in terms of luminescent bacteria test and unconfined compressive strength. The leachability of a field Zn- and Pb- contaminated soil stabilized with KMP is also evaluated by TCLP leaching test. The results show that the leached Zn concentrations are lower than the China MEP regulatory limit except when Zn and Pb coexist and for the curing time of 7 days. On the other hand, the leached Pb concentrations for stabilized soils with Pb alone or mixed Zn and Pb contamination are much lower than the China MEP or USEPA regulatory limit, irrespective of the curing time. The luminescent bacteria test results show that the toxicity of the stabilized soils has been reduced considerably and is classified as slightly toxic class. The unconfined compressive strength of the soils decrease with the increase in the Zn concentration. The stabilized soils with mixed Zn and Pb contaminants exhibit notably higher leached Zn concentration, while there is lower unconfined compressive strength relative to the soils when contaminated with Zn alone. The X-ray diffraction and scanning electron microscope analyses reveal the presence of bobierrite (Mg3(PO4)2·8H2O) and K-struvite (MgKPO4·6H2O) as the main products formed in the KMP stabilized uncontaminated soils; the formation of hopeite (Zn3(PO4)2·4H2O), scholzite (CaZn2(PO4)2·2H2O), zinc hydroxide (Zn(OH)2), and fluoropyromorphite (Pb5(PO4)3F) in the soils are the main mechanisms for immobilization of Zn and Pb with the KMP binder. The change in the relative quantities of the formed phosphate-based products, with respect to the Zn concentration and presence of mixed Zn and Pb contaminants, can well explain the measured impact of the Zn concentration levels and presence of both Zn and Pb contaminants on the unconfined compressive strength of the KMP stabilized soils.