Chidamide improves gefitinib treatment outcomes in NSCLC by attenuating recruitment and immunosuppressive function of myeloid-derived suppressor cells.

Clinical resistance to EGFR tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC) remains a significant challenge. Recent studies have indicated that the number of myeloid-derived suppressor cells (MDSCs) increases following gefitinib treatment, correlating with a poor patient response in NSCLC. Our study revealed that gefitinib treatment stimulates the production of CCL2, which subsequently enhances monocyte (M)-MDSC migration to tumor sites. Chidamide, a selective inhibitor of the histone deacetylase subtype, counteracted the gefitinib-induced increase in CCL2 levels in tumor cells. Additionally, chidamide down-regulated the expression of CCR2 in M-MDSCs, inhibiting their migration. Furthermore, chidamide attenuated the immunosuppressive function of M-MDSCs both alone and in combination with gefitinib. Chidamide also alleviated tumor immunosuppression by reducing the number of M-MDSCs in LLC-bearing mice, thereby enhancing the antitumor efficacy of gefitinib. In conclusion, our findings suggest that chidamide can improve gefitinib treatment outcomes, indicating that MDSCs are promising targets in NSCLC.

Ultrasmall polyvinylpyrrolidone-modified iridium nanoparticles with antioxidant and anti-inflammatory activity for acute pancreatitis alleviation.

Acute pancreatitis (AP) is a common and serious acute inflammatory disease with high severity rate and mortality. Inflammation and oxidative stress play an extremely important role in the development of AP disease. Polyvinylpyrrolidone-modified iridium nanoparticles (IrNP-PVP) have multienzyme mimetic activity, and the aim of this article is to discuss the therapeutic alleviative effects of the ultrasmall nanozymes IrNP-PVP on AP through their antioxidant and anti-inflammatory effects. IrNP-PVP were proved to inhibit inflammation and scavenge reactive oxygen species (ROS) at the cellular level. The synthetic IrNP-PVP exhibit remarkable antioxidant and anti-inflammatory activities in the prevention and treatment of AP mice by establishing murine AP model, which can reduce the oxidative stress and inflammatory response. The results of this article indicated that the ultrasmall nanozymes IrNP-PVP effectively alleviate AP via scavenging ROS as well as suppressing inflammation both in vivo and in vitro, which might provide enormous promise for the AP management.

A 26-week repeated dose toxicity evaluation of sporoderm-removed Ganoderma lucidum spores in rats.

Ganoderma lucidum spore powder is a traditional Chinese medicine with a variety of health benefits. Sporoderm-removed Ganoderma lucidum spores (RGLS) can be more effectively absorbed and utilized by the body. Due to the extensive clinical application and lack of long-term (>30 days) safety evaluation of RGLS, it is necessary to evaluate its repeated dose toxicity during a longer administration period. Here, we conducted a 26-week repeated dose toxicity test of RGLS in Sprague‒Dawley (SD) rats. The male and female rats were orally administered RGLS at doses of 0, 0.4, 1.2, and 4.0 g/kg once daily for a period of 26 weeks. The safety profile of RGLS was assessed through in vivo observations of survival, body weight, and food consumption; hematological, biochemical, and urine analyses; immunotoxicity assays; and histopathological examinations. The results showed that no significant systemic toxicity was observed following 26 weeks of repeated RGLS administration. Our data showed a no-observed adverse effect level (NOAEL) of 4.0 g/kg, which is approximately 20 times higher than the human equivalent dose. Our results support that RGLS can be considered a safe medicinal or food product that can be added to a healthy diet.

A repeat-dose toxicity study of human umbilical cord mesenchymal stem cells in NOG mice by intravenous injection.

BACKGROUND: Stem cell-based therapies have demonstrated great potential in several clinical trials. However, safety data on stem cell application remain inadequate. This study evaluated the toxicity of human umbilical cord mesenchymal stem cells (hUC-MSCs) in NOD/Shi-scid/IL-2 Rγnull (NOG) mice. RESEARCH DESIGN AND METHODS: Mice were administered hUC-MSCs intravenously at doses of 3.5 × 106 cells/kg and 3.5 × 107 cells/kg. Toxicity was assessed by clinical observation, behavioral evaluation, pathology, organ weight, and histopathology. We determined the distribution of hUC-MSCs using a validated qPCR method and colonization using immunohistochemistry. RESULTS: No significant abnormal effects on clinical responses, body weight, or food intake were observed in the mice, except for two in the high-dose group that died during the last administration. Mouse activity in the high-dose group decreased 6 h after the first administration. Terminal examination revealed dose-dependent changes in hematology. The mice in the high-dose group displayed pulmonary artery wall plaques and mild alveolar wall microthrombi. hUC-MSCs colonized primarily the lung tissues and were largely distributed there 24 h after the final administration. CONCLUSIONS: The no observed adverse effect level for intravenous administration of hUC-MSCs in NOG mice over a period of 3 w was 3.5 × 106 cells/kg.

Repeat-dose toxicity study of human umbilical cord mesenchymal stem cells in cynomolgus monkeys by intravenous and subcutaneous injection.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are proposed for the treatment of acute lung injury and atopic dermatitis. To advance hUC-MSC entry into clinical trials, the effects of hUC-MSCs on the general toxicity, immune perturbation and toxicokinetic study of hUC-MSCs in cynomolgus monkeys were assessed. hUC-MSCs were administered to cynomolgus monkeys by intravenous infusion of 3.0 × 106 or 3.0 × 107cells/kg or by subcutaneous injection of 3.0 × 107cells/kg twice a week for 3 weeks followed by withdrawal and observation for 6 weeks. Toxicity was assessed by clinical observation, clinical pathology, ophthalmology, immunotoxicology and histopathology. Moreover, toxicokinetic study was performed using a validated qPCR method after the first and last dose. After 3rd or 4th dosing, one or three the monkeys in the intravenous high-dose group exhibited transient coma, which was eliminated by slow-speed infusion after 5th or 6th dosing. In all dose groups, hUC-MSCs significantly increased NEUT levels and decreased LYMPH and CD3+ levels, which are related to the immunosuppressive effect of hUC-MSCs. Subcutaneous nodules and granulomatous foci were found at the site of administration in all monkeys in the subcutaneous injection group. Other than above abnormalities, no obvious systemic toxicity was observed in any group. The hUC-MSCs was detectable in blood only within 1 h after intravenous and subcutaneous administration. The present study declared the preliminary safety of hUC-MSCs, but close monitoring of hUC-MSCs for adverse effects, such as coma induced by intravenous infusion, is warranted in future clinical trials.

Developmental and reproductive toxicity of a recombinant protein subunit COVID-19 vaccine (ZF2001) in rats.

ZF2001, a protein subunit vaccine against coronavirus disease 2019 (COVID-19), contains recombinant tandem repeat of dimeric receptor-binding domain (RBD) protein of the SARS-CoV-2 spike protein with an aluminium-based adjuvant. During the development of this vaccine, two nonclinical studies were conducted to evaluate female fertility, embryo-fetal development, and postnatal developmental toxicity in Sprague‒Dawley rats according to the ICH S5 (R3) guideline. In Study 1 (embryo-fetal developmental toxicity, EFD), 144 virgin female rats were randomly assigned into four groups and received three doses of vaccine (25 µg or 50 µg RBD protein/dose, containing the aluminium-based adjuvant), the aluminium-based adjuvant or a sodium chloride injection administered intramuscularly on days 21 and 7 prior to mating and on gestation day (GD) 6. In Study 2 (pre- and postnatal developmental toxicity, PPND), ZF2001 at a dose of 25 µg RBD protein/dose or sodium chloride injection was administered intramuscularly to female rats (n = 28 per group) 7 days prior to mating and on GD 6, GD 20 and postnatal day (PND) 10. There were no obvious adverse effects in dams, except for local injection site reactions related to the aluminium-based adjuvant (yellow nodular deposits in the interstitial muscle fibres). There were also no effects of ZF2001 on the mating performance, fertility or reproductive performance of parental females, embryo-fetal development, postnatal survival, growth, physical development, reflex ontogeny, behavioural and neurofunctional development, or reproductive performance of the offspring. The strong immune responses associated with binding and neutralising antibodies were both confirmed in dams and fetuses or offspring in these two studies. These results would support clinical trials or the use of ZF2001 in maternal immunisation campaigns, including those involving women with childbearing potential, regardless of pregnancy status.

Plasma Metabolic Analysis Reveals the Dysregulation of Short-Chain Fatty Acid Metabolism in Parkinson's Disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder, characterized by high morbidity, high disability rate, and slow course of disease. The clinical diagnostic method of PD is complex and time-consuming, and there is no clear biomarker for clinical use. We aimed to investigate the plasma metabolites in PD and find out potential biomarkers with diagnostic ability. In the analysis of more than 40 metabolites including short-chain fatty acids, long-chain fatty acids, amino acids, and carbohydrates, the difference of short-chain fatty acids was observed. Acetic acid concentration was higher in PD than in healthy controls, and propanoic acid and 2,3,4-trihydroxybutyric acid were lower in PD. Compared with the early stage of PD, acetic acid increased significantly in the advanced stage of PD. Propanoic acid increased significantly in medicated PD compared with drug naïve PD. ROC analysis revealed acetic acid discriminated PD from healthy controls with 100% sensitivity, 88.9% specificity, and an area under the curve (AUC) of 0.981, and propanoic acid discriminated PD from healthy controls with an AUC of 0.981, 100% sensitivity, and 94.4% specificity. Acetic acid and propanoic acid may be a potential biomarker for differentiating PD from health, and the propanoic acid was evaluated as the most potential diagnostic marker because of its extremely high sensitivity and specificity.

Preclinical Toxicity and Immunogenicity of a COVID-19 Vaccine (ZF2001) in Cynomolgus Monkeys.

Although the new coronavirus disease 2019 (COVID-19) outbreak occurred in late 2019, it is still endemic worldwide, and has become a global public health problem. Vaccination against SARS-CoV-2 is considered to be the most effective intervention to prevent the spread of COVID-19. ZF2001 is a recombinant protein vaccine based on SARS-CoV-2 receptor-binding domain (RBD) subunit which contains aluminum adjuvant. In order to advance our research on ZF2001 into clinical trial, we investigated the general toxicity and immunogenicity of ZF2001 in cynomolgus monkeys and assessed the possible target organs for vaccine-induced toxicity. In the present research, we observed no significant systemic toxicities and abnormal cardiovascular and respiratory events following four times injections of intramuscular ZF2001 in cynomolgus monkeys. Histological examination revealed recoverable inflammatory changes in quadricep muscle and adjacent lymph node at the vaccine injection site. As expected, the vaccine can produce a strongly specific binding antibody and neutralizing antibodies in cynomolgus monkeys after inoculation. Taken together, our regulatory toxicology research proves the safety and immunogenicity of the ZF2001 vaccine, supporting its entry into large scale clinical trials.

Chemical profiling of Fritillariae thunbergii Miq prepared by different processing methods reveals two new quality markers: Zhebeininoside and imperialine-3-ß-D-glucoside.

ETHNOPHARMACOLOGICAL RELEVANCE: Fritillariae thunbergii Miq (FTM)exhibit versatile biological activities including the significant antitussive and expectorant activities. As a herbal medicine, the therapeutic effects of FTM may be expressed by multi-components which have complicated integration effects on multi-targets. With the time going, the different processing methods of FTM has been changed a lot. Thus，the study described the effect of processing methods to FTM and its quality. MATERIAL AND METHOD: Studies were undertaken by using UHPLC-LTQ Orbitrap MS and pharmacodynamic models. All reagents were involved of analytical grade. While a HPLC-ELSD's method has been developed and validated, a certified Quality System is conformed to ICH requirements. The experimental animals followed the animal welfare guidelines. AIM OF THE STUDY: We aimed to found the differences after the different processing methods of FTM, and to demonstrate the changes could be selected as quality control indicators, and established a method for simultaneous determination of these for quality control. RESULTS: we have previously found two new steroidal alkaloids: zhebeininoside and imperialine-3-ß-D-glucoside from the different processing methods of FTM, which is the difference between the different processing methods of FTM, mainly on the steroidal alkaloids. The activity analysis of zhebeininoside, imperialine-3-ß-D-glucoside, verticine and verticinone showed that the mouse model of cough expectorant has antitussive effect. The positive drug selected was dextromethorphan syrup. The positive group showed biological activity, but the blank group showed nothing. The model group showed illness which means that the model was effective. There are two ways of the mechanism of action of the expectorant action which can make sputum thin, reduce its viscosity, and be easy to cough up, or can accelerate the movement of mucous cilia in the respiratory tract and promote the discharge of sputum. In our study, the content of phenol red was significantly reduced in the administration group. CONCLUSIONS: To sum up, our results suggest that zhebeininoside and other three components cloud be selected as quality control indicators, and a method for simultaneous determination of zhebeininoside and other three components was established for quality control.

Validation, Optimization, and Application of the Zebrafish Developmental Toxicity Assay for Pharmaceuticals Under the ICH S5(R3) Guideline.

The zebrafish as an alternative animal model for developmental toxicity testing has been extensively investigated, but its assay protocol was not harmonized yet. This study has validated and optimized the zebrafish developmental toxicity assay previously reported by multiple inter-laboratory studies in the United States and Europe. In this study, using this classical protocol, of 31 ICH-positive compounds, 23 compounds (74.2%) were teratogenic in zebrafish, five had false-negative results, and three were neither teratogenic nor non-teratogenic according to the protocol standard; of 14 ICH-negative compounds, 12 compounds (85.7%) were non-teratogenic in zebrafish and two had false-positive results. After we added an additional TI value in the zebrafish treated with testing compounds at 2 dpf along with the original 5 dpf, proposed a new category as the uncategorized compounds for those TI values smaller than the cutoff both at 2 dpf and 5 dpf but inducing toxic phenotypes, refined the testing concentration ranges, and optimized the TI cut-off value from ≥ 10 to ≥ 3 for compounds with refined testing concentrations, this optimized zebrafish developmental assay reached 90.3% sensitivity (28/31 positive compounds were teratogenic in zebrafish) and 88.9% (40/45) overall predictability. Our results from this study strongly support the use of zebrafish as an alternative in vivo method for screening and assessing the teratogenicity of candidate drugs for regulatory acceptance.

Targeted fatty acid metabolomics to discover Parkinson's disease associated metabolic alteration.

The pathogenesis of Parkinson's disease (PD) remains to be elucidated, and the metabolomics analysis has the potential to identify metabolic profiles that are involved in PD pathogenesis. Here we applied a target metabolomics approach to measure the plasma levels of 158 fatty acid metabolites in a discovery cohort including 42 PD patients and 54 health volunteers, and found two upregulated (arachidonic acid and 13-hydroxy-octadecatrienoic acid) and eleven down-regulated (docosahexaenoic acid, lyso-platelet-activating factor, 12-hydroxy-eicosatetraenoic acid, dihydroxy-eicosatrienoic acids, dihidroxy-octadecenoic acids, 17,18-dihydroxy-eicosatetraenoic acid, and hydroperoxy-octadecadienoic acids) metabolites as primary candidate marker of PD. A support vector machine algorithm with primary candidate marker was used in an independent validation cohort to identify PD. Arachidonic acid and 13-hydroxy-octadecatrienoic acid were evaluated as an effective tool in that area under the receiver operating characteristic curve reached 0.995 and 0.912 in the validation set for diagnosing PD from healthy volunteers. Besides, the sensitivity and specificity of arachidonic acid as diagnostic factor of PD in validation set were 100% and 94.10%. Similarly, the sensitivity and specificity of 13-hydroxy-octadecatrienoic acid were 100% and 82.40% for identifying PD. This target fatty acid metabolomics demonstrated a series of plasma fatty acid metabolite as PD candidate marker with high efficiency and provided insights into the understanding of PD metabolic regulation.

Root Extract of Lindera aggregata (Sims) Kosterm. Modulates the Th17/Treg Balance to Attenuate DSS-Induced Colitis in Mice by IL-6/STAT3 Signaling Pathway.

Ulcerative colitis (UC) is a chronic, idiopathic and relapsing inflammatory disease of the gastrointestinal tract that has a prolonged disease duration. Lindera aggregata (Sims) Kosterm. is a traditional Chinese herb which has been used to treat gastrointestinal diseases for thousand years. However, there are few reports about the application of L. aggregata in the treatment of UC at present. Herein, we investigated the therapeutic effect of the root extract of L. aggregata (LREE) against UC and explored its underlying mechanisms based on IL-6 signaling pathway and the balance of T helper (Th) 17 and regulatory T (Treg) cells. Results showed that LREE could not only decrease the production and secretion of IL-6, but also could inhibit the signal transduction of IL-6/STAT3 signaling pathway. Moreover, LREE could significantly inhibit the differentiation of CD4+ T cells to Th17 cells in vitro and decrease the proportion of Th17 cells in mesenteric lymph nodes (MLNs) of model mice in vivo. Besides, LREE could also alleviate the disease symptoms, reduce intestinal permeability and improve histopathological changes of colitis model mice. Together, LREE can significantly inhibit the production and secretion of IL-6, regulate IL-6/STAT3 signal transduction, and modulate the balance of Th17 and Treg cells and effectively attenuate UC.

Association of occupational burnout and occupational exposure factors on psychological health among factory workers and miners: a propensity score analysis.

PURPOSE: This study is to explore the association of occupational burnout and occupational exposure factors on psychological health among factory workers and miners. METHODS: A total of 6130 factories workers and miners in Urumqi, China were included using a cluster sampling method. The occupational burnout and psychological health were investigates using the Chinese Maslach Burnout Inventory (CMBI) and the Symptom Check List-90 (SCL-90). The propensity score analysis (PSA) was used to eliminate the influence of individual characteristics, and 2164 pairs of participants on psychological healthy and unhealthy were matched. After PSA, the relationship between occupational burnout, occupational hazard exposure, and psychological health was evaluated. RESULTS: The results showed that asbestos dust (OR 1.65, CI 95% 1.35-2.02) and CMBI (OR 2.59, CI 95% 2.39-2.83) were risk factors affecting psychological health (P < 0.001). CONCLUSIONS: Measures need to be taken to ease occupational burnout among factories workers and miners, and strengthen personal protection to improve their psychological health.

Establishment of Reference Intervals for Umbilical Arterial Blood from Healthy Neonates in the Hulunbuir Area of China.

BACKGROUND: This study aimed to establish reference intervals for blood gas analyses of umbilical arterial blood from healthy neonates in the Hulunbuir area of China. METHODS: APGAR scores of 8 - 10 (1-min intervals) were obtained for umbilical arterial blood collected from 2,845 healthy newborns during 2,016 - 2,018 based on 10 items - pH, PCO2, PO2, K+, Na+, Cl-, Ca2+, lactic acid (Lac), hemoglobin (Hb), base excess (BE) - using the electrode method. Means ± 1.96 SD were used to establish reference ranges. RESULTS: Reference intervals obtained were pH 7.25 ± 0.13, PCO2 53.8 ± 20.6 mmHg, PO2 20.8 ± 10.3 mmHg, K+ 4.34 ± 1.32 mmol/L, Na+ 132.4 ± 4.30 mmol/L, Cl- 105.22 ± 5.51 mmol/L, Ca2+ 1.35 ± 0.13 mmol/L, Lac 3.36 ± 1.75 mmol/L, Hb 15.62 ± 3.06 g/dL, BE -4.62 ± 3.28 mmol/L. CONCLUSIONS: These results can help evaluate hypoxia associated with neonatal ischemia in the clinical setting and provide a basis for establishing references for umbilical arterial blood gas in other geographic regions.

Mn-substituted goethite for uranium immobilization: A study of adsorption behavior and mechanisms.

Goethite is a common iron hydroxide, which can be substituted by manganese (Mn) in the goethite structure. It is important to investigate the immobilization of uranium(VI) on Mn-substituted goethite (Mn-Goe) to understand the fate and migration of uranium in soils and sediments. In this study, the sorption of uranium(VI) by Mn-Goe was investigated as a function of pH, adsorbent dosage, contact time, and initial uranium concentration in batch experiments. Several material analysis techniques were used to characterize manganese substituted materials. Results indicated that Mn was successfully introduced into the goethite structure, the length of particles increased gradually, the surface clearly exhibited higher roughness with increasing Mn content, and that uranium(VI) sorption of synthetic Mn-Goe appeared to be higher than that of goethite. The sorption kinetics supported the results presented by the pseudo-second-order model. The sorption capacity of uranium on Mn-Goe was circa 77 mg g-1 at pH = 4.0 and 25 °C. Fourier transform-infrared spectroscopy (FT-IR) analyses revealed that uranium ions were adsorbed through functional groups containing oxygen on the Mn-Goe structure. The enhancement of Mn-substitution for the uranium(VI) sorption capacity of goethite was revealed. This study suggests that goethite and Mn-Goe can both play a significant role in controlling the mobility and transport of uranium(VI) in the subsurface environment, which is helpful for material development in environmental remediation.

The Status of Occupational Burnout and Its Influence on the Psychological Health of Factory Workers and Miners in Wulumuqi, China.

The purpose of this study was to investigate the status of occupational burnout and its influence on the psychological health of factory workers and miners, in order to provide theoretical basis and reference for alleviating occupational burnout and promoting psychological health. The cross-sectional study investigated 6130 factory workers and miners with online questionnaire; the Chinese Maslach Burnout Inventory (CMBI) and Symptom Check List-90 (SCL-90) were used. In total, 6120 valid questionnaires were collected; effectiveness was 99.8%. The percentage of the factory workers and miners suffering from occupational burnout was 85.98% and psychological health problems was 38.27%. A statistically significant difference was observed in relation to the prevalence of occupational burnout among factory workers and miners of different sex, education level, labor contracts, work schedule, monthly incomes, weight, hypertension, age, working years, working hours per day, working hours per week, coal dust, silica dust, asbestos dust, benzene, lead, and noise. The detection rate of psychological health was higher for males than females. The detection rate of psychological health was higher for working days per week less than 5 days than more than 5 days. The detection rate of psychological health with high school education, senior professional title, night shift, divorced, monthly income less than 3000 yuan, weight more than 75 kg, age more than 45 years, and working years between 25 and 30 years was higher than that of the other groups. The results showed that sex, education level, professional title, work schedule, monthly income, hypertension, age, working years, asbestos dust, benzene, and occupational burnout affected psychological health among factory workers and miners. Factory workers and miners had high levels of occupational burnout, and occupational burnout was a risk factor that can lead to psychological health.

Application of a DSS colitis model in toxicologically assessing norisoboldine.

In standard nonclinical drug safety evaluation studies, limitations exist in predicting the clinical risk of a drug based only on data from healthy animals. To obtain more comprehensive toxicological information on norisoboldine (NOR), we conducted an exploratory study using C57BL/6 mice in addition to healthy mice as models of dextran sodium sulfate (DSS) colitis to evaluate the safety of NOR. The healthy mice and DSS colitis mice were exposed to 30 or 90 mg NOR/kg body weight or water for 15 days. Compared with the model control group, 90 mg/kg of NOR aggravated the symptoms and colonic lesions of the DSS colitis mice and even caused death in two animals. No significant adverse effects were observed in the healthy mice. These different toxic reactions to NOR in the healthy and DSS colitis mice indicate that NOR toxicity varies by status among animals and suggests that the DSS colitis mouse model may be more susceptible, accurate and comprehensive in evaluating the safety of NOR. In conclusion, 90 mg/kg of NOR may be safe for healthy mice but not for DSS colitis mice. The DSS colitis mouse model, with many features similar to those of human colitis patients, may be a novel choice to counteract the deficiencies of using healthy mice to evaluate the safety of anti-inflammatory bowel disease (IBD) drugs, and further research is required.

A Comparative Study on the Prediction of Occupational Diseases in China with Hybrid Algorithm Combing Models.

Occupational disease is a huge problem in China, and many workers are under risk. Accurate forecasting of occupational disease incidence can provide critical information for prevention and control. Therefore, in this study, five hybrid algorithm combing models were assessed on their effectiveness and applicability to predict the incidence of occupational diseases in China. The five hybrid algorithm combing models are the combination of five grey models (EGM, ODGM, EDGM, DGM, and Verhulst) and five state-of-art machine learning models (KNN, SVM, RF, GBM, and ANN). The quality of the models were assessed based on the accuracy of model prediction as well as minimizing mean absolute percentage error (MAPE) and root-mean-squared error (RMSE). Our results showed that the GM-ANN model provided the most precise prediction among all the models with lowest mean absolute percentage error (MAPE) of 3.49% and root-mean-squared error (RMSE) of 1076.60. Therefore, the GM-ANN model can be used for precise prediction of occupational diseases in China, which may provide valuable information for the prevention and control of occupational diseases in the future.

Understanding the solid phase chemical fractionation of uranium in soil profile near a hydrometallurgical factory.

Uranium (U) contamination of soil has become a major concern with respect to its toxicity, accumulation in the food chain, and persistence in the environment. Anthropogenic activities like mining and processing of U ores has become pressing issues throughout the world. The aim of the work is to understand the chemical fractionation of U in polluted soil and the mechanism involved. U-free soils samples of eluvial (E), illuvial (B), and parent-material (C) horizons from a hydrometallurgical factory area were used. The experimental results showed that the U adsorption capacity decreased with depth, and its mobility in the upper soil is better than the lower. It was closely related to distribution coefficient (Kd), pH, organic-matter (OM), and carbonate content of soil horizons. The chemical fractionation of U was studied using the BCR sequential extraction scheme for soils after saturated adsorption. It was noted that the U reducible and oxidizable fraction in the E and B horizons can vertically transfer to the C horizon and occurs a significant rearrangement of U in different horizons. BET, SEM, XRD, and FT-IR analyses showed that different U distribution and migration in soil profile is mainly affected by specific surface area, soil particle size, mineral composition, and active groups. The XPS data further indicated that U (VI) is gradually converted to U (IV) with decreased depth and fixed in deeper soil becoming insoluble and immobile. It is the first step to investigate potential migration and plan U mining and milling area long-term management.