Long-term conservation tillage enhances microbial carbon use efficiency by altering multitrophic interactions in soil.

Microbial carbon (C) use efficiency (CUE) plays a key role in soil C storage. The predation of protists on bacteria and fungi has potential impacts on the global C cycle. However, under conservation tillage conditions, the effects of multitrophic interactions on soil microbial CUE are still unclear. Here, we investigate the multitrophic network (especially the keystone ecological cluster) and its regulation of soil microbial CUE and soil organic C (SOC) under different long-term (15-year) tillage practices. We found that conservation tillage (CT) significantly enhanced microbial CUE, turnover, and SOC (P < 0.05) compared to traditional tillage (control, CK). At the same time, tillage practice and soil depth had significant effects on the structure of fungal and protistan communities. Furthermore, the soil biodiversity of the keystone cluster was positively correlated with the microbial physiological traits (CUE, microbial growth rate (MGR), microbial respiration rate (Rs), microbial turnover) and SOC (P < 0.05). Protistan richness played the strongest role in directly shaping the keystone cluster. Compared with CK, CT generally enhanced the correlation between microbial communities and microbial physiological characteristics and SOC. Overall, our results illustrate that the top-down control (the organisms at higher trophic levels affect the organisms at lower trophic levels) of protists in the soil micro-food web plays an important role in improving microbial CUE under conservation tillage. Our findings provide a theoretical basis for promoting the application of protists in targeted microbial engineering and contribute to the promotion of conservation agriculture and the improvement of soil C sequestration potential.

Associations of Sleep Patterns With Dynamic Trajectory of Cardiovascular Multimorbidity and Mortality: A Multistate Analysis of a Large Cohort.

Background The purpose of this study was to explore the association of sleep patterns with the development of first cardiovascular diseases (FCVD), progression to cardiovascular multimorbidity (CVM), and subsequently to mortality. Methods and Results This prospective study included 381 179 participants without coronary heart disease, stroke, atrial fibrillation, or heart failure at baseline, and they were followed up until March 31, 2021. We generated sleep patterns by summing the scores for 5 sleep behaviors, whereby <7 or >8 hours/d of sleep, evening chronotype, frequent insomnia, snoring, and daytime dozing were defined as high-risk groups. We used a multistate model to estimate the impacts of sleep patterns on the dynamic progression of cardiovascular diseases. Over a median follow-up of 12.1 years, 41 910 participants developed FCVD, 7302 further developed CVM, and 20 707 died. We found that adverse sleep patterns were significantly associated with the transition from health to FCVD, from FCVD to CVM, and from health to death, with hazard ratio associated with 1-factor increase in sleep scores being 1.08 (95% CI, 1.07-1.09), 1.04 (95% CI, 1.02-1.06), and 1.04 (95% CI, 1.02-1.05), respectively. When further dividing FCVD into coronary heart disease, stroke, atrial fibrillation, and heart failure, adverse sleep patterns showed a significant and persistent effect on the transition from health to each cardiovascular disease, and from heart failure or atrial fibrillation to CVM. Conclusions Our study provides evidence that adverse sleep patterns might increase the risk for the progression from health to cardiovascular diseases and further to CVM. Our findings suggest that improving sleep behaviors might be helpful for the primary and secondary prevention of cardiovascular diseases.

Peroxymonosulfate-Activation-Induced Phase Transition of Mn3O4 Nanospheres on Nickel Foam with Enhanced Catalytic Performance.

The transformations of physicochemical properties on manganese oxides during peroxymonosulfate (PMS) activation are vital factors to be concerned. In this work, Mn3O4 nanospheres homogeneously loaded on nickel foam are prepared, and the catalytic performance for PMS activation is evaluated by degrading a target pollutant, Acid Orange 7, in aqueous solution. The factors including catalyst loading, nickel foam substrate, and degradation conditions have been investigated. Additionally, the transformations of crystal structure, surface chemistry, and morphology on the catalyst have been explored. The results show that sufficient catalyst loading and the support of nickel foam play significant roles in the catalytic reactivity. A phase transition from spinel Mn3O4 to layered birnessite, accompanied by a morphological change from nanospheres to laminae, is clarified during the PMS activation. The electrochemical analysis reveals that more favorable electronic transfer and ionic diffusion occur after the phase transition so as to enhance catalytic performance. The generated SO4•- and •OH radicals through redox reactions of Mn are demonstrated to account for the pollutant degradation. This work will provide new understandings of PMS activation by manganese oxides with high catalytic activity and reusability.

Dynamic association of ambient air pollution with incidence and mortality of pulmonary hypertension: A multistate trajectory analysis.

BACKGROUND: There is little evidence regarding the association between ambient air pollution and incidence and the mortality of pulmonary hypertension (PH). METHODS: We included 494,750 participants at baseline in the UK Biobank study. Exposures to PM2.5, PM10, NO2, and NOx were estimated at geocoded participants' residential addresses, utilizing pollution data provided by UK Department for Environment, Food and Rural Affairs (DEFRA). The outcomes were the incidence and mortality of PH. We used multivariate multistate models to investigate the impacts of various ambient air pollutants on both incidence and mortality of PH. RESULTS: During a median follow-up of 11.75 years, 2517 participants developed incident PH, and 696 died. We observed that all ambient air pollutants were associated with increased incidence of PH with different magnitudes, with adjusted hazard ratios (HRs) [95% confidence intervals (95% CIs)] for each interquartile range (IQR) increase of 1.73 (1.65, 1.81) for PM2.5, 1.70 (1.63, 1.78) for PM10, 1.42 (1.37, 1.48) for NO2, and 1.35 (1.31, 1.40) for NOx. Furthermore, PM2.5, PM10, NO2 and NO2 influenced the transition from PH to death, and the corresponding HRs (95% CIs) were 1.35 (1.25, 1.45), 1.31 (1.21, 1.41), 1.28 (1.20, 1.37) and 1.24 (1.17, 1.32), respectively. CONCLUSION: The results of our study indicate that exposure to various ambient air pollutants might play key but differential roles in both the incidence and mortality of PH.

Ambient air pollution and incidence, progression to multimorbidity and death of hypertension, diabetes, and chronic kidney disease: A national prospective cohort.

BACKGROUND: The link between ambient air pollution and the incidence of hypertension, diabetes, and chronic kidney disease (CKD) has been widely studied. However, the associations of air pollution with the dynamic progression to multimorbidity and mortality of these diseases are unknown. METHODS: This study included 162,334 participants from the UK Biobank. Multimorbidity was defined as the coexistence of at least two of hypertension, diabetes, and CKD. Land use regression was used to estimate annual concentrations of particulate matter (PM2.5), PM10, nitrogen dioxide (NO2), and nitrogen oxides (NOx). Multi-state models were used to assess the association between ambient air pollutants and the dynamic progression of hypertension, diabetes, and CKD. RESULTS: During a median follow-up of 11.7 years, 18,496 participants experienced at least one of hypertension, diabetes, and CKD, 2216 experienced multimorbidity, and 302 died afterwards. We observed differential associations of four air pollutants on different transitions from healthy status to incident disease (hypertension, diabetes, or CKD), to multimorbidity, and to death. The hazard ratios (HRs) of each IQR increment in PM2.5, PM10, NO2, and NOx for the transition to incident disease were 1.07 [95 % confidence intervals (CI): 1.04, 1.09], 1.02 (1.00, 1.03), 1.07 (1.04, 1.09), and 1.05 (1.03, 1.07), but the associations with the transition to death were significant for NOx only [HR: 1.04 (95 % CI: 1.01, 1.08)]. CONCLUSIONS: Air pollution exposure might be one important determinant for the incidence and dynamic progression of hypertension, diabetes, and CKD, suggesting that more attention should be paid to ambient air pollution control in the prevention of hypertension, diabetes, and CKD, as well as their progression.

Air pollution associated with incidence and progression trajectory of chronic lung diseases: a population-based cohort study.

BACKGROUND: No prior study has examined the effects of air pollution on the progression from healthy to chronic lung disease, subsequent chronic lung multimorbidity and further to death. METHODS: We used data from the UK Biobank of 265 506 adults free of chronic lung disease at recruitment. Chronic lung multimorbidity was defined as the coexistence of at least two chronic lung diseases, including asthma, chronic obstructive pulmonary disease and lung cancer. The concentrations of air pollutants were estimated using land-use regression models. Multistate models were applied to assess the effect of air pollution on the progression of chronic lung multimorbidity. RESULTS: During a median follow-up of 11.9 years, 13 863 participants developed at least one chronic lung disease, 1055 developed chronic lung multimorbidity and 12 772 died. We observed differential associations of air pollution with different trajectories of chronic lung multimorbidity. Fine particulate matter showed the strongest association with all five transitions, with HRs (95% CI) per 5 µg/m3 increase of 1.31 (1.22 to 1.42) and 1.27 (1.01 to 1.57) for transitions from healthy to incident chronic lung disease and from incident chronic lung disease to chronic lung multimorbidity, and 1.32 (1.21 to 1.45), 1.24 (1.01 to 1.53) and 1.91 (1.14 to 3.20) for mortality risk from healthy, incident chronic lung disease and chronic lung multimorbidity, respectively. CONCLUSION: Our study provides the first evidence that ambient air pollution could affect the progression from free of chronic lung disease to incident chronic lung disease, chronic lung multimorbidity and death.

Exposure to Air Pollution during Pre-Hypertension and Subsequent Hypertension, Cardiovascular Disease, and Death: A Trajectory Analysis of the UK Biobank Cohort.

BACKGROUND: The associations between air pollution exposure and morbidity and mortality of cardiovascular diseases (CVDs) have been widely reported; however, evidence on such associations across different dynamic disease trajectories remain unknown. OBJECTIVE: We examined whether ambient air pollution during the prehypertension (pre-HTN) stage could aggravate the progression from hypertension (HTN) to CVD, and consequent death. METHODS: A total of 168,010 adults with pre-HTN (120-139 mmHg systolic blood pressure or 80-89 mmHg diastolic blood pressure) from the UK Biobank were included in this analysis. We used a multistate model to explore the associations between five air pollutants (PM2.5, PM2.5 absorbance, PM10, NO2, and NOx) and the risk of six disease transitions (from pre-HTN to HTN, from pre-HTN to CVD, from pre-HTN to death, from HTN to CVD, from HTN to death, and from CVD to death). Mediation analyses were further conducted to explore the role of intermediate diseases in the dynamic progression of CVDs. RESULTS: During a median follow-up of 12 y, 13,743 (8.18%) of participants with pre-HTN developed HTN, whereas 12,825 (7.63%) and 4,467 (2.66%) directly developed CVD or died, respectively. Air pollution was positively associated with the dynamic disease progression. For example, a per-interquartile range increase of PM2.5 was significantly associated with the hazard ratios (HRs) of 1.105 [95% confidence intervals (CI): 1.083, 1.127], 1.045 (95% CI: 1.022, 1.068), and 1.086 (95% CI: 1.047, 1.126) in the transition from pre-HTN to HTN, CVD, and death, respectively. Higher levels of air pollution were associated with increased transition probability of disease progression. Mediation analyses indicated that intermediate diseases subsequently significantly mediated air pollutant-associated risk to develop more serious disease. CONCLUSIONS: This study provides evidence that air pollution might play a role in the early stages of CVD progression. Controlling air pollution might be an effective measure to prevent CVD progression and reduce the disease burden of CVD. https://doi.org/10.1289/EHP10967.

Ambient air pollution, bone mineral density and osteoporosis: Results from a national population-based cohort study.

Evidence concerning the associations of ambient air pollution exposure with bone mineral density and osteoporosis has been mixed. We conducted cross-sectional and prospective analysis of the associations between air pollution exposure and osteoporosis using data from UK Biobank study. Estimated bone mineral density (eBMD) of each participant at baseline survey was calculated using quantitative ultrasound data, and incident osteoporosis cases were identified during the follow-up period according to health-related records. Air pollution concentrations were assessed using land use regression models. We fitted multivariable linear and logistic regression models to estimate the associations of air pollution with eBMD and osteoporosis prevalence at baseline. We applied cox proportional hazard regression models to assess the relationships between air pollution and osteoporosis incidence. Among the 341,311 participants at baseline, higher air pollution exposure was associated with lower eBMD levels and increased odds of osteoporosis prevalence. For example, an IQR increase in PM2.5, PM2.5 absorbance, PM10, NO2 and NOx levels were associated with 0.0018 (95% CI: 0.0012, 0.0023) to 0.0052 (95% CI: 0.0046, 0.0058) g/cm2 decrease in eBMD. A total of 330,988 participants without osteoporosis were followed up for an average of 12.0 years. We identified 8105 incident osteoporosis cases (456 cases with pathological fracture and 7634 cases without pathological fracture) during the follow-up. The hazard ratios for an interquartile range increase in PM2.5, PM2.5 absorbance, PM10, NO2 and NOx were 1.09 (95% CI: 1.06, 1.12), 1.04 (95% CI: 1.02, 1.07), 1.04 (95% CI: 1.01, 1.07), 1.07 (95% CI: 1.04, 1.10), and 1.06 (95% CI: 1.03, 1.09), respectively. Our study suggests that ambient air pollution might be a risk factor of decreased bone mineral density and osteoporosis incidence.

Ambient air pollution associated with incidence and progression trajectory of cardiometabolic diseases: A multi-state analysis of a prospective cohort.

BACKGROUND: Previous studies on the association between ambient air pollution and cardiometabolic diseases (CMDs) focused on a single disease, without considering cardiometabolic multimorbidity (CMM) and the progression trajectory of CMDs. METHODS: Based on the UK Biobank cohort, we included 372,530 participants aged 37-73 years at baseline (2006-2010) with follow-up until September 2021. Incident CMDs cases were identified based on self-reported information and multiple health-related records in the UK Biobank. CMM was defined as the occurrence of at least two CMDs, including ischemic heart disease (IHD), stroke and type 2 diabetes (T2D). Exposure to ambient air pollutants, including particulate matter (PM) with aerodynamic diameter ≤2.5 µm (PM2.5), ≤10 µm (PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOx) were estimated at participants' geocoded residential addresses based on the high-resolution (1 × 1 km) pollution data from 2001 to 2021 provided by UK Department for Environment, Food and Rural Affairs. Multi-state models with adjustment for potential confounders were used to examine the impact of long-term exposure to ambient air pollution on transitions from healthy to first CMD (FCMD), subsequently to CMM, and further to death. RESULTS: During a median follow-up of 12.6 years, 40,112 participants developed at least one CMD, 3896 developed CMM, and 21,739 died. Among the four pollutants, PM2.5 showed the strongest associations with all transitions from healthy to FCMD, to CMM, and then to death [hazard ratios (95 % confidence intervals) per interquartile range (IQR) increment: 1.62 (1.60, 1.64) and 1.68 (1.61, 1.76) for transitions from healthy to FCMD and from FCMD to CMM, and 1.62 (1.59, 1.66), 1.67 (1.61, 1.73), and 1.52 (1.38, 1.67) for death risk from healthy, FCMD, and CMM, respectively]. After dividing FCMDs into three specific CMDs, we found that ambient air pollution had differential impacts on disease-specific transitions within the same transition phase. CONCLUSIONS: Our findings indicate that there is potential for air pollution mitigation in contributing to the prevention of the development and progression of CMDs.

Freeze-thaw cycles lead to enhanced colloid-facilitated Pb transport in a Chernozem soil.

Freeze-thaw cycles in soils lead to break up of soil aggregates and the formation of dispersible soil colloids. Leaching events following freeze-thaw cycles can therefore mobilize and transport colloids through the soil profile. Here, we investigated the effect of freeze-thaw cycles on the subsequent mobilization of colloids in a Pb contaminated soil, and we quantified the amount of colloid-facilitated Pb transport. Soil contaminated with Pb (250 mg/kg or 1000 mg/kg) was packed into 15 cm tall columns, and the soil water content adjusted to field capacity (0.306 kg/kg). Columns were subjected to freeze-thaw cycles of 12 h freezing at -20 °C followed by 12 h of thawing at 25 °C. Then, the soil columns were leached with distilled water, and the effluent was analyzed for colloids, soluble Pb, and colloidal-bound Pb. Freeze-thaw cycles were found to generate dispersible soil colloids and lead to colloid-facilitated Pb transport. Colloid and Pb mobilization increased with increasing number of freeze-thaw cycles. The majority (83-97%) of the Pb that leached out of the columns was colloid-bound. Our findings suggest that freeze-thaw cycles in high latitude areas can mobilize heavy metals, which are otherwise immobile, through colloid-facilitated transport. More frequent freeze-thaw cycles in high-latitude regions, as predicted by climate change models, thus increases the risk of metal leaching from contaminated soils and can lead to subsequent ground water pollution.

Ambient air pollution associated with incidence and dynamic progression of type 2 diabetes: a trajectory analysis of a population-based cohort.

BACKGROUND: Though the association between air pollution and incident type 2 diabetes (T2D) has been well documented, evidence on the association with development of subsequent diabetes complications and post-diabetes mortality is scarce. We investigate whether air pollution is associated with different progressions and outcomes of T2D. METHODS: Based on the UK Biobank, 398,993 participants free of diabetes and diabetes-related events at recruitment were included in this analysis. Exposures to particulate matter with a diameter ≤ 10 µm (PM10), PM2.5, nitrogen oxides (NOx), and NO2 for each transition stage were estimated at each participant's residential addresses using data from the UK's Department for Environment, Food and Rural Affairs. The outcomes were incident T2D, diabetes complications (diabetic kidney disease, diabetic eye disease, diabetic neuropathy disease, peripheral vascular disease, cardiovascular events, and metabolic events), all-cause mortality, and cause-specific mortality. Multi-state model was used to analyze the impact of air pollution on different progressions of T2D. Cumulative transition probabilities of different stages of T2D under different air pollution levels were estimated. RESULTS: During the 12-year follow-up, 13,393 incident T2D patients were identified, of whom, 3791 developed diabetes complications and 1335 died. We observed that air pollution was associated with different progression stages of T2D with different magnitudes. In a multivariate model, the hazard ratios [95% confidence interval (CI)] per interquartile range elevation in PM2.5 were 1.63 (1.59, 1.67) and 1.08 (1.03, 1.13) for transitions from healthy to T2D and from T2D to complications, and 1.50 (1.47, 1.53), 1.49 (1.36, 1.64), and 1.54 (1.35, 1.76) for mortality risk from baseline, T2D, and diabetes complications, respectively. Generally, we observed stronger estimates of four air pollutants on transition from baseline to incident T2D than those on other transitions. Moreover, we found significant associations between four air pollutants and mortality risk due to cancer and cardiovascular diseases from T2D or diabetes complications. The cumulative transition probability was generally higher among those with higher levels of air pollution exposure. CONCLUSIONS: This study indicates that ambient air pollution exposure may contribute to increased risk of incidence and progressions of T2D, but to diverse extents for different progressions.

Air Pollution Associated With Incident Stroke, Poststroke Cardiovascular Events, and Death: A Trajectory Analysis of a Prospective Cohort.

BACKGROUND AND OBJECTIVE: Ambient air pollution has been widely linked with morbidity and mortality of stroke. However, its effects on dynamic progression trajectory of stroke remain unknown.We investigated the effects of ambient air pollution on progression trajectory from healthy status to incident stroke, poststroke cardiovascular diseases, and subsequent death. METHODS: We retrieved 318,752 participants from the UK Biobank. The annual concentrations of air pollution [particulate matter (PM2.5, PMcoarse, PM10 and PM2.5 absorbance), nitrogen dioxide (NO2), and nitrogen oxides (NOx)] were estimated through land use regressions. A multistate regression model was used to investigate the effects of air pollution on each stage of the progression of stroke. RESULTS: During 3,765,630 person-years of follow-up, we identified 5,967 incident stroke patients, 2,985 poststroke cardiovascular patients, and 1,020 deaths afterward. Each 5 µg/m3 increase in PM2.5, NO2, and NOx was associated with the transition from healthy status to incident stroke [hazard ratios (HRs) (95% confidence intervals (CI)) = 1.24 (1.10, 1.40); 1.02 (1.00, 1.03); 1.01 (1.00, 1.02)] and transitions from healthy status to death directly [1.30 (1.21, 1.40); 1.03 (1.02, 1.04); and 1.02 (1.01, 1.02)]. We also observed positive associations for poststroke CVDs, especially for NO2 [1.04 (95% CI: 1.02, 1.06)], but these effects gradually declined for mortality outcome. DISCUSSION: This study provides the first evidence that ambient air pollution is one important factor associated with the progression of stroke, and the effects differed across different clinical stages. A better understanding of the differential effects of air pollutants on different stroke transition stages could provide valuable insight toward targets for health management and clinical prevention.

The effects of ambient fine particulate matter exposure and physical activity on heart failure: A risk-benefit analysis of a prospective cohort study.

BACKGROUND: Evidence supporting the adverse effects of air pollution and the benefits of physical activity (PA) on heart failure (HF) has continued to grow. However, their joint effects remain largely unknown. METHODS: Our investigation included a total of 321,672 participants free of HF at baseline from the UK Biobank. Participants were followed up till March 2021. Information on participants' PA levels and additional covariates was collected by questionnaire. The annual fine particulate matter (PM2.5) concentration was estimated using a Land Use Regression (LUR) model. Cox proportional hazards models were used to assess the associations of PA and PM2.5 exposure with incident HF, as well as their interaction on both additive and multiplicative scales. RESULTS: During a median follow-up of 12.0 years, 8212 cases of HF were uncovered. Compared with participants with low PA, the hazard ratios (HRs) were 0.69 (95 % CI: 0.65, 0.73) and 0.61 (95 % CI: 0.58, 0.65) for those with moderate and high PA, respectively. PM2.5 was associated with an elevated risk of incident HF with an HR of 1.11 (95 % CI: 1.08, 1.14) per interquartile range (IQR) increment. The synergistic additive interaction between low PA and high PM2.5 exposure on HF was observed. Compared with participants with high PA and low PM2.5 exposure, those with low PA and high PM2.5 exposure had the highest risk of HF [HR (95 % CI): 1.90 (1.76, 2.06)]. CONCLUSIONS: Our findings indicate that PA might still be an appropriate strategy to prevent HF for those living in areas with relatively high air pollution. Individuals with low PA may pay more attention to air pollution.

Application of biochar-immobilized Bacillus sp. KSB7 to enhance the phytoremediation of PAHs and heavy metals in a coking plant.

The co-existence of heavy metals and polycyclic aromatic hydrocarbons (PAHs) challenges the remediation of polluted soil. This study aimed to investigate whether a combined amendment of biochar-immobilized bacterium (BM) could enhance the phytoremediation of heavy metals and PAHs in co-contaminated soil. The Bacillus sp. KSB7 with the capabilities of plant-growth promotion, metal tolerance, and PAH degradation was immobilized on the peanut shell biochar prepared at 400 °C and 600 °C (PBM4 and PBM6, respectively). After 90 days, PBM4 treatment increased the removal of PAHs by 94.17% and decreased the amounts of diethylenetriamine pentaacetic acid-extractable Zn, Pb, Cr, and Cu by 58.46%, 53.42%, 84.94%, and 83.15%, respectively, compared with Kochia scoparia-alone treatment. Meanwhile, PBM4 was more effective in promoting K. scoparia growth and reducing the uptake of co-contaminants. The abundance of Gram-negative PAH-degrader and 1-aminocyclopropane-1-carboxylic deaminase-producing bacteria within rhizosphere soil was significantly improved after PBM4 treatment. Moreover, the relative abundance of the Bacillus genus increased by 0.66 and 2.05 times under PBM4 treatment compared with biochar alone and KSB7, indicating that KSB7 could colonize in the rhizosphere soil of K. scoparia. However, the removal of PAHs and heavy metals after PBM6 and 600 °C biochar-alone treatments caused no obvious difference. This study suggested that low-temperature BM-amended plant cultivation would be an effective approach to remove PAHs and heavy metals in co-contaminated soil.

Synergistic roles of montmorillonite and organic matter in reducing bioavailable state of chromium in tannery sludge.

Organic matter (OM) has an excellent retention effect on stabilizing chromium (Cr), and functional groups on OM play a predominant role in this process. Based on this result, it is found that a considerable amount of Cr in tannery sludge is immobilized from ion exchangeable species into bound species, benefiting from complexing reaction with functional groups. Especially, the mentioned immobilizing process is enhanced in way of adding with montmorillonite (MMT) which performs adsorption reaction with Cr, as well as plays interaction with functional groups. The result is confirmed by employing density functional theory (DFT) analysis, suggesting the binding ability among Cr, functional groups, and MMT is stronger (- 77.36503 eV) than that of the system of Cr and MMT (- 61.29942 eV), indicating the synergetic roles of OM and MMT. This synergetic role could also be illustrated by a new peak (Cr-OH 20.1%) shown in XPS result. Meanwhile, DFT analysis emphasizes that functional groups on OM give the response for binding with Cr in the order of hydroxyl (-OH) > carboxyl (-COOH) > epoxy (-COC), and all the functional groups tend to donate electron to bind with Cr. In addition, the stabilizing process shows a better fitting effect with pseudo second-order kinetic model (R2 > 0.94), indicating that exchangeable Cr mass transfer and chemical adsorption occur simultaneously.

Performance and Mechanisms of Sulfidated Nanoscale Zero-Valent Iron Materials for Toxic TCE Removal from the Groundwater.

Trichloroethylene (TCE) is one of the most widely distributed pollutants in groundwater and poses serious risks to the environment and human health. In this study, sulfidated nanoscale zero-valent iron (S-nZVI) materials with different Fe/S molar ratios were synthesized by one-step methods. These materials degraded TCE in groundwater and followed a pathway that did not involve the production of toxic byproducts such as dichloroethenes (DCEs) and vinyl chloride (VC). The effects of sulfur content on TCE dechlorination by S-nZVI were thoroughly investigated in terms of TCE-removal efficiency, H2 evolution, and reaction rate. X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) characterizations confirmed Fe(0) levels in S-nZVI were larger than for zero-valent iron (nZVI). An Fe/S molar ratio of 10 provided the highest TCE-removal efficiencies. Compared with nZVI, the 24-h TCE removal efficiencies of S-nZVI (Fe/S = 10) increased from 30.2% to 92.6%, and the Fe(0) consumed during a side-reaction of H2 evolution dropped from 77.0% to 12.8%. This indicated the incorporation of sulfur effectively inhibited H2 evolution and allowed more Fe(0) to react with TCE. Moreover, the pseudo-first-order kinetic rate constants of S-nZVI materials increased by up to 485% compared to nZVI. In addition, a TCE degradation was proposed based on the variation of detected degradation products. Noting that acetylene, ethylene, and ethane were detected rather than DCEs and VC confirmed that TCE degradation followed ß-elimination with acetylene as the intermediate. These results demonstrated that sulfide modification significantly enhanced nZVI performance for TCE degradation, minimized toxic-byproduct formation, and mitigated health risks. This work provides some insight into the remediation of chlorinated-organic-compound-contaminated groundwater and protection from secondary pollution during remediation by adjusting the degradation pathway.

Effect of strip clear-cutting on the natural regeneration of Pinus tabuliformis plantations in northeastern China.

In this study, the effect of strip clear-cutting on the natural regeneration performance of mature Pinus tabuliformis plantations in the three locations in western part of the Liaoning Province was analyzed. Strip clear-cutting, with clear-cut and uncut strip widths of 15, 20, 25 m, and 10 and 18 m, respectively, was conducted in spring 2014, and control, in each study location. Field investigations were conducted in 2017. Fifteen sample plots with sizes of 4 m2 (2 m × 2 m) were established in each clear-cut strip, uncut strip, and control. One to four saplings were randomly selected to measure the current year increment, and the lengths and numbers for branch of the first whorl. Three saplings were randomly selected from the center of the strip to measure the photosynthetic rate. Three sample plots with sizes of 4 m2 (2 m × 2 m) and 1 m2 (1 m × 1 m) were developed in each strip and control to determine the biodiversity of shrubs and herbs as well as the water content of the decomposition and semi-decomposition layer. The results show that the current year increment and branch length of the first whorl can be ordered as follows: clear-cut strips > control > uncut strips. Number of the branches of the first whorl can be ordered as follows: clear-cut strips > uncut strips > control. Strip clear-cutting was a statistically significant treatment for the current year increment and length and number of branches of the first whorl. The saplings from the clear-cut strip with a width of 25 m have the largest photosynthetic capacity compared with those from the other strips and control. The transpiration rates of the large, medium, and small saplings from clear-cut strips are the largest and those of saplings from the control are the smallest. The water content of the decomposition and semi-decomposition layer in the control is the highest, but no significant difference was confirmed between the strip clear-cutting approaches.

Regulation of photosynthetic material production by inter-root microbial extinction and metabolic pathways in sorghum under different nitrogen application patterns.

The development of nitrogen fertilizer green and efficient application technology by exploring the mechanism of efficient sorghum N use is important for sustainable development of sorghum industry as well as barren marginal land development and utilization. This study was conducted in 2018, 2019, and 2020 at Shenyang, China, using the nitrogen-efficient sorghum variety Liaonian No. 3 as material. The correlation between soil microbial species, diversity, and metabolic pathways with photosynthetic parameters and yield traits was analyzed to elucidate the mechanisms of nitrogen utilization and photosynthetic material production in sorghum under four fertilizer application patterns. The results showed that 17 populations of soil inter-root microorganisms were active in the organic fertilizer + 0 kg per hm2 of nitrogen (N0Y) model, and the abundance of two key populations, Comamonadaceae and Ellin5301, was significantly increased. Soil microorganisms regulated sorghum growth mainly through 30 pathways, focus including ko00540, ko00471, ko00072 and ko00550, of which ko02030 (Bacterial chemotaxis) and ko00072 (Synthesis and degradation of ketone bodies) played the most critical role. The functional analysis of soil microbial populations revealed that N0Y fertilizer model significantly reduced the intracellular trafficking, secretion. In addition, vesicular transport of microorganisms, amino acid transport and metabolism and nucleotide transport and metabolism played a key role in the regulation of population function. Overall, the N0Y model of N-efficient sorghum can achieve high levels of photosynthetic material production and higher yield formation through regulation of population activities and metabolic pathways of loamy microorganisms, resulting in reduced chemical N application and efficient green production of sorghum.

Immobilizing chromium in tannery sludge via adding collagen protein waste: an in-depth study on mechanism.

Owing to containing high fraction of organic matter, the tannery sludge seemed to be fit for composting. Actually, it was intensively harmful to the environment, due to containing chromium (Cr). So it might undergo a long time of storage until finding a proper way to dispose it. In the storage period, it would expose the surrounding environment a risk via releasing Cr. In this study, an approach was proposed to minimize the amount of released Cr, and reveal the mechanism on immobilizing Cr. Collagen protein waste (CPW) was adopted to immobilize Cr, and it was evaluated via leaching experiment. The lowest leaching concentration of Cr was 12 mg/L, meeting the limits of related standard in China (GB 5085.3-2007, Tcr < 15 mg/L). Moreover, the compositions and functional groups of the optimum sample (12 mg/L) were also characterized, confirming that the dominant functional groups cross-linking with Cr were hydroxyl (-OH), carboxyl (-COOH), and epoxy (-COC). Importantly, density functional theory (DFT) calculation was also employed, suggesting that Cr was restrained by accepting electrons from O atoms donating by functional groups.