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The human body loading with arsenic (As) through rice consumption is a global health concern. There is a crucial need to limit As build-up in rice, either by remediating As accumulation in soils or reducing As levels in irrigation water. Several conventional approaches have been utilized to alleviate the As accumulation in rice. However, except for some irrigation practices, those approaches success and the adoption rate are not remarkable. This review presents human health risks posed due to consumption of As contaminated rice, evaluates different biomarkers for tracing As loading in the human body, and discusses the latest advancement in As reducing technologies emphasizing the application of seed priming, nanotechnology, and biochar application for limiting As loading in rice grains. We also evaluate different irrigation techniques to reduce As accumulation in rice. Altering water management regimes significantly reduces grain As accumulation. Bio- and nano-priming of rice seeds improve germination and minimize As translocation in rice tissues by protecting cell membrane, building pool around seed coat, methylation and volatilization, or quenching harmful effects of reactive oxygen species. Nanoparticle application in the form of nano-adsorbents or nano-fertilizers facilitates nano-remediation of As through the formation of Fe plaque or sorption or oxidation process. Incorporating biochar in the rice fields significantly reduces As through immobilization, physical adsorption, or surface complexation. In conclusion, As content in cooked rice depends on irrigation source and raw rice As level. [ABSTRACT FROM AUTHOR]

As using iron-based materials and biomass to prepare effective catalyst has emerged as a hit trend in persulfate-based advanced oxidation processes (PS-AOPs), the problems associated with excessive chemical consumption, costly expenses, and complex synthetic processes have become more urgent to be addressed. Therefore, by using red mud (RM) and corn straw (CS), a modified red mud biochar catalyst (MRBC) was synthesized through acid pretreatment and pyrolysis (700 °C). MRBC presented excellently in peroxydisulfate (PDS) activation to degrade levofloxacin (LFX). Under the experimental setup involving 8 mM PDS, 10 mg L−1 LFX, and 1.6 g L−1 MRBC, 88.59% of LFX was effectively eliminated within 30 min with an exceedingly low Fe leaching rate of 0.049 mg L−1. Furthermore, even after four cycles of reuse, it was able to sustain a remarkable 61.63% efficiency in LFX degradation. The characterization of catalysts demonstrated the synergistic effect of RM and biomass could be responsible for the excellent catalytic properties of MRBC. The results of quenching experiment and the presence of DMPOX in EPR demonstrated radical pathway mainly contributed to the LFX degradation in MRBC/PDS system. Overall, PDS was activated by the active sites of MRBC such as Fe (II) and persistent free radicals (PFRs) to generate a large amount of SO 4 •− and •OH to remove LFX. This work investigated the synergy of RM and biomass in catalyst preparation, deepened the insights into the application of RM catalysts in PS-AOPs to degrade antibiotic, and contributed greatly to the recovery of waste resources. [Display omitted] • 88.59% removal of LFX within 30 min was achieved by MRBC/PDS system. • The synergistic effect of red mud and biochar enhanced the PDS activation. • The modification of HNO 3 promoted surface structure and iron element proportion. • Results of quenching experiments and EPR confirmed radical pathway degrade LFX. [ABSTRACT FROM AUTHOR]

Abstract This work reports the use of ferrioxalate complexes to assist solar photo-Fenton treatment of pentachlorophenol (PCP) in aqueous medium at mild pH, which inhibits the precipitation of iron hydroxides and allows working at a low iron dosage. The experimental parameters were optimized by assessing the effect of initial concentrations of H 2 O 2 (0–2.5 mM) and Fe(II) (2–10 mg/L), pH (3.0–9.0) and iron/oxalic acid molar ratios (1:0–1:13.5) on total organic carbon (TOC) removal. Ferrioxalate-assisted solar photo-Fenton achieved 97.5% mineralization in 120 min, clearly outperforming conventional Fenton and solar photo-Fenton. The presence of photosensitive ferrioxalate complexes accounted for the enhancement, as a result of Fe(II) regeneration that accelerated the hydroxyl radical (OH) production. The time course of H 2 O 2 and Fe(II) concentrations was evaluated under different iron/oxalic acid ratios. The five carboxylic acids determined by ion-exclusion HPLC and the eight aromatic by-products identified by GC-MS allowed the proposal of a degradation pathway that included hydroxylation, dechlorination and dimerization steps. Complete chloride ion release was achieved after 90 min of treatment. Highlights • Up to 97.5% mineralization achieved by ferrioxalate-assisted solar photo-Fenton process. • Similar TOC abatement was obtained within pH range 3.0–6.0 • Complete dechlorination of PCP at 90 min using low iron dosage (5 mg/L) at pH 5.0 • Fe(III) was maintained soluble, being efficiently reduced to Fe(II) in the presence of oxalate. • Up to 8 aromatic products found by GC-MS: hydroxylation, dechlorination and dimerization. [ABSTRACT FROM AUTHOR]

Abstract The removal of benzophenone-3 (BP-3), a ubiquitous pollutant in municipal wastewater treatment facilities, was optimal by means of a sequential electrocoagulation (EC)/UVA photoelectro-Fenton (PEF) treatment. Overall mineralization was attained upon combination of EC (Fe/Fe cell, 15 mA cm−2, 20 min) with PEF (boron-doped diamond/air-diffusion cell, 33.3 mA cm−2, 720 min), being superior to EC/electro-Fenton (EF) and requiring shorter time than single PEF. In EC, an Al/Al cell yielded the largest removal of BP-3 in a simulated matrix at pH 11.0 due to precipitation of its neutral form caused by a substantial pH drop, with optimum current density of 15 mA cm−2. EC of BP-3-loaded urban wastewater at natural pH was quite effective also with a Fe/Fe cell, being preferred since it provided the required metal catalyst for subsequent treatment. Among the electrochemical advanced oxidation processes tested, PEF was superior to electrochemical oxidation with electrogenerated H 2 O 2 (EO-H 2 O 2) and EF, especially when using the boron-doped diamond instead of a RuO 2 -based anode, due to the oxidation of generated active chlorine and hydroxyl radicals, along with the photolytic action of UVA irradiation. GC-MS revealed the formation of 14 cyclic products in PEF treatment, two of them being also formed during EC. Graphical abstract Image 1 Highlights • Best benzophenone-3 and TOC decays in simulated matrix at pH 11.0 by EC with Al/Al cell. • Greater pollutant degradation in urban wastewater by PEF with BDD/air-diffusion cell. • Identification of 14 organic products by GC-MS in PEF with BDD/air-diffusion cell. • Sequential EC (Fe/Fe cell)/PEF (BDD/air-diffusion cell) better than EC/EF and PEF. • First investigation of EC/EAOPs coupling to treat organic pollutants in urban wastewater. [ABSTRACT FROM AUTHOR]

Aims The purpose of this paper was to fabricate PLLA/PCL nanofibrous scaffolds containing HAP to mimic the native bone extracellular matrix for potential applications as bone tissue engineering scaffolds materials and ultimately to help the repairing of bone defects. Materials and methods PLLA (MW 200 kDa), PCL (MW 80 kDa), HAP, dichloromethane, N , N -dimethylformamide; α-MEM, FBS, trypsin-EDTA, penicillin G, streptomycin, β-sodium glycerophosphate, l -ascorbic acid, dexamethasone; CCK-8, Alkaline Phosphatase Assay Kit, Mouse Osteocalcin ELISA Kit, MC3T3-E1 cells. PLLA, PCL and HAP were dissolved in the solution of DCM and DMF to fabricate nanofibrous scaffolds through electrospinning. The morphology of the scaffolds was investigated with SEM, while the diameter of the fibers, pore size and water uptake of the scaffolds were tested, respectively. TGA was carried out to verify the percentage of HAP in the composite scaffolds fabricated with different HAP concentrations. Cell count kit-8 assay, alkaline phosphatase (ALP) assay, and osteocalcin assay were applied to observe the MC3T3-E1 cells proliferation, differentiation on the composite scaffolds. Key findings MC3T3-E1 cells were found to grow actively on the composite scaffolds based on the results of CCK-8 assay. The level of MC3T3-E1 differentiation was evaluated through the ALP activity and osteocalcin concentration, which showed higher value with HAP containing (PLLA/PCL/HAP) than that ones without (PLLA/PCL). Significance The results demonstrated that the biocomposite PLLA/PCL/HAP nanofibrous scaffold should be a promising candidate for proliferation, differentiation and mineralization of osteoblasts, and potentially can be used for bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Leachate, a highly polluted wastewater, is generated from landfill containing complex compositions which have great impact on the environment. The advanced treatment of biochemically treated landfill leachate using electrochemically assisted UV/chlorine process (UEC) in a flow reactor was investigated. The effects of pH and current density on COD and NH 3 -N removal by UEC process were evaluated. At the pH value of 5.0, current density of 60 mA/cm 2 , the removal efficiencies for COD and NH 3 -N were observed as 77% and 87%, respectively. The electrochemical process alone (EC) could obtain relatively high NH 3 -N removal but very low COD removal, compared with which, the UEC process significantly promoted the removal efficiency of COD while that of NH 3 -N increased to a very limited extent. Most of NH 3 -N was converted into N 2 and little nitrogen compounds and chloramines were remained in the leachate after 8 h treatment. Moreover, the variations of active chlorine and chloride ions were monitored in the EC and UEC systems, and a possible mechanism was proposed for the UEC process. The in situ electro-generated active chlorine and photo-generated radical species should be responsible for the efficient degradation of landfill leachate. The total energy consumption and current efficiency were 216.5 (kW h/kg COD) and 17.5%, respectively, for 8 h treatment. In addition, the molecular weight (MW) percentage distribution analysis and PARAFAC analysis of excitation emission matrix (EEM) fluorescence spectroscopy indicated that the organic matters in the leachate were significantly degraded into the fractions with small molecular weight. [ABSTRACT FROM AUTHOR]

Abstract: Microbe-assisted phytoremediation has been considered as a promising measure for the remediation of heavy metal-polluted soils. In this study, a metal-tolerance and plant growth-promoting endophytic bacterium JN6 was firstly isolated from roots of Mn-hyperaccumulator Polygonum pubescens grown in metal-contaminated soil and identified as Rahnella sp. based on 16S rDNA gene sequence analysis. Strain JN6 showed very high Cd, Pb and Zn tolerance and effectively solubilized CdCO3, PbCO3 and Zn3(PO4)2 in culture solution. The isolate produced plant growth-promoting substances such as indole-3-acetic acid, siderophore, 1-aminocyclopropane-1-carboxylic deaminase, and also solubilized inorganic phosphate. Based upon its ability in metal tolerance and solubilization, the isolate JN6 was further studied for its effects on the growth and accumulation of Cd, Pb and Zn in Brassica napus (rape) by pot experiments. Rape plants inoculated with the isolate JN6 had significantly higher dry weights, concentrations and uptake of Cd, Pb and Zn in both above-ground and root tissues than those without inoculation grown in soils amended with Cd (25mgkg−1), Pb (200mgkg−1) or Zn (200mgkg−1). The isolate also showed a high level of colonization in tissue interior of rapes. The present results demonstrated that Rahnella sp. JN6 is a valuable microorganism, which can cost-effectively improve the efficiency of phytoremediation in soils contaminated by Cd, Pb and Zn. [Copyright &y& Elsevier]

Rice consumption has been identified as a major route of methylmercury (MeHg) exposure in some areas of inland China. We investigated two potential mitigation methods (water management and deliberate selection of rice cultivars) to reduce the amount of total mercury (Hg) and MeHg within the grain. Rice grown aerobically had markedly reduced total Hg and MeHg concentrations as well as a much lower proportion of MeHg in the grain. Remarkably, there were considerable variations in the total Hg and MeHg concentrations as well as the proportion of MeHg in the grain among the 24 cultivars grown in the same paddy soil. The Hg tolerance index (expressed as % mean of control root growth) also varied substantially among the different cultivars. Furthermore, negative correlations were found between the total Hg and MeHg concentrations (P <0.05) of grain and the proportion of MeHg in the grain (P <0.01). [Copyright &y& Elsevier]

This work reports the novel application of an Fe-based 2D metal−organic framework (MOF), prepared with 2,2′-bipyridine-5,5′-dicarboxylate (bpydc) as organic linker, as highly active catalyst for heterogeneous photoelectro-Fenton (PEF) treatment of the lipid regulator bezafibrate in a model matrix and urban wastewater. Well-dispersed 2D structures were successfully synthesized and their morphological, physicochemical and photocatalytic properties were assessed. UV/Vis PEF using an IrO 2 /air-diffusion cell with an extremely low catalyst concentration (0.05 g L−1, tenfold lower than reported 3D MOFs) outperformed electro-oxidation with electrogenerated H 2 O 2 , electro-Fenton and visible-light PEF. Its excellent performance was explained by: (i) the enhanced mass transport of H 2 O 2 (and organic molecules) at the 2D structure, providing active sites for heterogeneous Fenton's reaction and in-situ Fe(II) regeneration; (ii) the ability of photoinduced electrons to reduce H 2 O 2 to •OH, and Fe(III) to Fe(II); and (iii) the enhanced charge transfer and excitation of Fe–O clusters, which increased the number of electron-hole pairs. LC-QToF-MS and GC-MS allowed the identification of 16 aromatic products of bezafibrate. The complete removal of four micropollutants mixed in urban wastewater at pH 7.4 revealed the great potential of (Fe−bpydc)-catalyzed PEF process. Image 1 • Fe−based 2D MOF degrades various organic micropollutants at mild pH via PEF catalysis. • Complete degradation of bezafibrate by UV/Vis PEF using only 0.05 g L−1 Fe−based 2D MOF. • 16 primary oxidation products of bezafibrate detected by LC-QToF-MS and GC-MS. • Detailed mechanism for PEF with Fe−based 2D MOF: heterogeneous Fenton + photocatalysis. • Thorough study on the stability, recyclability and electronic structure of Fe−based 2D MOF. [ABSTRACT FROM AUTHOR]

The radial translocation of cadmium (Cd) from the root to the shoot is one of the major processes affecting Cd accumulation in rice (Oryza sativa L.) grains, but few studies have focused on Cd apoplastic transport in rice. The aim of this study was to determine how apoplastic barriers affect Cd translocation via the apoplastic pathway, Cd accumulation levels in upper parts (shoot and grains) of rice cultivars, and the possible mechanism involved. Hydroponic and soil pot trials were conducted to study the development and chemical constituents of apoplastic barriers and their permeability to bypass flow, and to determine Cd localization in the roots of rice cultivars with different Cd-accumulating characteristics. The Cd accumulation in upper parts was positively correlated with bypass flow in the root and the apparent Cd concentration in the xylem, indicating that the apoplastic pathway may play an important role in Cd root-shoot translocation in rice. Apoplastic barriers were deposited closer to the root tip and were thicker in low Cd-accumulating cultivars than in high Cd-accumulating cultivars. The amounts and rates of increase in lignin and suberin were significantly higher in ZD14 (a low Cd-accumulating cultivar) than in FYXZ (a high Cd-accumulating cultivar) under Cd stress, indicating that stronger barriers were induced by Cd in ZD14. The stronger and earlier formation of barriers in the low Cd-accumulating cultivar decreased bypass flow more efficiently, so that more Cd was retained in the root during apoplastic translocation. This was confirmed by localization analyses of Cd in root transverse sections. These results suggest that apoplastic barriers reduce Cd root-to-shoot translocation via the apoplastic pathway, leading to lower Cd accumulation in the upper parts of rice plants. Bypass flow may have the potential to be used as a rapid screening indicator for low Cd-accumulating rice cultivars. Image 1 • Apoplastic barriers reduced Cd transport into xylem via apoplastic pathway. • Cd low-accumulating cultivars had stronger and earlier-deposited barriers. • Stronger apoplastic barriers in low-accumulating cultivar retained more Cd in root. • Ability of develop barriers in response to stress also determined Cd accumulation. Root apoplastic barriers play an important role in Cd accumulation in rice. [ABSTRACT FROM AUTHOR]

This work reports the first investigation on the use of EDDS as chelating agent in photoelectro-Fenton (PEF) treatment of water at near-neutral pH. As a case study, the removal of the antidepressant fluoxetine was optimized, using an electrochemical cell composed of an IrO 2 -based anode an air-diffusion cathode for in-situ H 2 O 2 production. Electrolytic trials at constant current were made in ultrapure water with different electrolytes, as well as in urban wastewater (secondary effluent) at pH 7.2. PEF with Fe(III)–EDDS (1:1) complex as catalyst outperformed electro-Fenton and PEF processes with uncomplexed Fe(II) or Fe(III). This can be explained by: (i) the larger solubilization of iron ions during the trials, favoring the production of •OH from Fenton-like reactions between H 2 O 2 and Fe(II)–EDDS or Fe(III)–EDDS, and (ii) the occurrence of Fe(II) regeneration from Fe(III)–EDDS photoreduction, which was more efficient than conventional photo-Fenton reaction with uncomplexed Fe(III). The greatest drug concentration decays were achieved at low pH, using only 0.10 mM Fe(III)–EDDS, although complete removal in wastewater was feasible only with 0.20 mM Fe(III)–EDDS due to the greater formation of •OH. The effect of the applied current and anode nature was rather insignificant. A progressive destruction of the catalytic complex was unveiled, whereupon the mineralization mainly progressed thanks to the action of •OH adsorbed on the anode surface. Despite the incomplete mineralization using BDD as the anode, a remarkable toxicity decrease was determined. Fluoxetine degradation yielded F− and NO 3 − ions, along with several aromatic intermediates. These included two chloro-organics, as a result of the anodic oxidation of Cl− to active chlorine. A detailed mechanism for the Fe(III)–EDDS-catalyzed PEF treatment of fluoxetine in urban wastewater is finally proposed. Image 1 • Total fluoxetine removal at near-neutral pH by Fe(III)–EDDS-catalyzed PEF process. • Fe(III)–EDDS complex: great photoactivity to form Fe2+, and long iron solubilization. • 2 Degradation stages: •OH-mediated, followed by M(•OH)-mediated once EDDS disappeared • 11 Primary degradation by-products detected, including two chloro-organics. • Detailed mechanism for Fe(III)–EDDS-catalyzed PEF treatment in urban wastewater. [ABSTRACT FROM AUTHOR]

Close contacts of novel coronavirus disease 2019 (COVID-19) patients may suffer from physical and psychological problems. Few studies have investigated the quarantine experiences of close contacts of COVID-19 patients. The objective of this study was to best capture participants' quarantine experiences during the COVID-19 outbreak in China. A descriptive, qualitative design was used. All interviews were recorded and coded using thematic analysis. Fifteen participants took part in this study. The following five themes emerged: (1) experience in the early stage of quarantine; (2) experience in the middle stage of quarantine; (3) experience in the late stage of quarantine; (4) self-coping persisted throughout the quarantine period; and (5) external support was evident throughout the quarantine period. Our study highlights the need to assess the psychological state of close contacts in the early stage of quarantine and to provide psychological support for them, especially for the older and the less educated. Although close contacts had physical symptoms and psychological issues, they adopted positive coping strategies, which indicated that they were vulnerable but strong. Furthermore, external support from the Chinese government helped them cope with the quarantine effectively. Learning from the quarantine experience is expected to help the Chinese government and institutions from other parts of the world to better care for close contacts. [ABSTRACT FROM AUTHOR]

The association between sedentary behavior and health-related outcomes has been well established, whereas it is inconclusive whether a sedentary behavior pattern is an additional risk factor for health-related outcomes independent of total sedentary time and physical activity. To determine sedentary behavior patterns and their association with risks of noncommunicable diseases and all-cause mortality and to assess whether this association is independent of total sedentary time and physical activity. This was a systematic review and meta-analysis. Studies were obtained by searching the Web of Science Core Collection, PubMed/Medline, the Cochrane Library, Embase, CINAHL, and SPORTDiscus up to April 2023. All observational studies published in English or Chinese were included if they explored sedentary behavior patterns and their association with risks of abdominal obesity, metabolic syndrome, diabetes, cardiovascular disease, cancer, and all-cause mortality among individuals who had never experienced the outcome event before the baseline assessment. Data extraction using a standardized form and quality appraisal using two authoritative tools were then performed. All these steps were completed by two independent reviewers from December 2022 to May 2023. If data were sufficiently homogenous, meta-analyses were performed; otherwise, narrative syntheses were employed. Harvest plots were also used to visually represent the distribution of evidence. Eighteen studies comprising 11 prospective cohort studies and seven cross-sectional studies were included. The findings suggested that prolonged sedentary time and usual sedentary bout duration were two metrics that reflected the nonlinear dose–response effect of prolonged sedentary behavior patterns. Only extremely high levels of prolonged sedentary behavior patterns significantly increased the risk of adverse health outcomes, independent of physical activity. Whether prolonged sitting was an additional risk factor for adverse health outcomes, independent of total sedentary time, was inconclusive due to an insufficient number of primary studies that included total sedentary time as one of the potential covariates. There was some evidence that supported a sedentary bout that significantly increased the risk of adverse health outcomes was 30–60 min. The threshold of prolonged sedentary time differed with outcomes, and future studies are needed to make this threshold more precise. A prolonged sedentary behavior pattern was associated with increased risks of several major noncommunicable diseases and all-cause mortality. People, especially those who do not reach the recommended level of moderate-to-vigorous physical activity, are encouraged to interrupt sedentary bouts every 30 to 60 min and limit prolonged sedentary time per day as much as possible. Breaking up consecutive sedentary bouts > 30 to 60 min and substituting them with brief bouts of physical activity. [ABSTRACT FROM AUTHOR]

Abstract A clear description of the certain mechanisms of cadmium (Cd) uptake and translocation in rice (Oryza sativa L.) may help to reduce Cd accumulation in rice grain. Hydroponic experiments were carried out to determine the effects of cultivation conditions (aerated and stagnant) on the uptake, translocation and subcellular distribution of Cd in relation to the morphology and anatomy of roots in two rice genotypes with different Cd accumulations in grains. Marked differences in morphology and anatomy were observed between these two genotypes under different cultivation conditions. Genotypes with low Cd accumulation in grains tended to develop fewer root tips per root surface area, larger root porosity and more mature apoplastic barriers. The stagnant cultivation condition decreased the number of root tips per root surface area but increased root porosity and accelerated apoplastic barrier formation in root tissues. Correlative Cd uptake studies revealed that rice plants with fewer number of root tips per root surface area reduced root Cd uptake ability, while mature apoplastic barriers increased root Cd retention in cell walls and the symplast. Thus, the fewer number of root tips per root surface area and the earlier formation of mature apoplastic barriers led to lower Cd uptake and translocation. The results indicated that the morphology and anatomy of roots could play important roles in Cd uptake and translocation in rice, and could be influenced by both genotype and cultivation conditions. The present results would be useful in screening and planting rice plants with low Cd accumulation. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract In order to help mitigate widespread cadmium (Cd) and arsenic (As) co-contamination in paddy soils in China, screening and breeding of low-accumulating rice ( Oryza sativa L.) cultivars (excluders) have been widely adopted. However, the performance of rice cultivars for grain Cd and As accumulation may vary in different growing environments. The inability to identify stable low-accumulating cultivars has largely hindered their application. In this study, 51 rice cultivars were evaluated at four Cd- and As-contaminated paddy sites in two crop seasons in northern Guangdong Province, China. The aim was to investigate the effects of cultivar, environment and their interactions in determining grain Cd and As concentrations, and so to identify stable low-accumulating cultivars. Results showed that environment effects dominated the Cd and As concentrations in rice grains, explaining 87% of the total variations. The crop season played a vital role; compared to early season, grain Cd levels increased and As levels lowered significantly in late season. Large variations in grain Cd, total As, inorganic As concentrations and the percentage of inorganic As were observed between different cultivars. Conventional japonica cultivars exhibited lower Cd levels but higher As levels in the grains than did indica cultivars. The cultivar × environment interaction (CEI) was significant, and its importance was comparable to the cultivar effect. By measuring and interpreting such an interaction, stable Cd and As excluder cultivars were identified based upon the yield, grain Cd and As levels as well as the stabilities of cultivars across the trial environments. Two stable Cd and As co-excluders were found among the hybrid indica cultivars. These results demonstrated that the variations in grain Cd and As concentrations could mainly be attributed to the environment effects and cultivar selection practices should include the analysis of CEI to identify stable low-accumulating rice cultivars. Graphical abstract Unlabelled Image Highlights • The environment and crop season are crucial in determining grain Cd and As. • Two hybrid indica cultivars exhibited stable Cd and As co-exclusion. • Stable excluders could be identified by analyzing cultivar × environment interaction. [ABSTRACT FROM AUTHOR]

Contamination of rice ( Oryza sativa ) by Cd is of great concern. Steel slag could be used to amend Cd-contaminated soils and make them safe for cereal production. This work was conducted to study the effects of steel slag on Cd uptake and growth of rice plants in acidic and Cd-contaminated paddy soils and to determine the possible mechanisms behind these effects. Pot (rhizobag) experiments were conducted using rice plants grown on two acidic and Cd-contaminated paddy soils with or without steel slag amendment. Steel slag amendment significantly increased grain yield by 36–45% and root catalase activity, and decreased Cd concentrations in brown rice by 66–77% compared with the control, in both soils. Steel slag amendment also markedly decreased extractable soil Cd, Cd concentrations in pore-water and Cd translocation from roots to above-ground parts. It also significantly increased soil pH, extractable Si and Ca in soils and Ca concentrations in roots. Significant positive correlations were found between extractable soil Cd and Cd concentrations in rice tissues, but it was negatively correlated with soil pH and extractable Si. Calcium in root tissues significantly and negatively correlated with Cd translocation factors from roots to straw. Overall, steel slag amendment not only significantly promoted rice growth but decreased Cd accumulation in brown rice. These benefits appear to be related to improvements in soil conditions (e.g. increasing pH, extractable Si and Ca), a reduction in extractable soil Cd, and suppression of Cd translocation from roots to above-ground parts. [ABSTRACT FROM AUTHOR]

Agricultural waste was characterized by large quantity and low degree of resource utilization. The peanut shell waste was converted into value-added biochar to alleviate the pollution of dyeing wastewater, which caters to the concept of resource recovery and sustainable utilization. In this work, peroxydisulfate (PDS) could be efficiently activated by biochar obtained by pyrolysis at 700 °C (BC) and Acid Orange 7 (AO7) was rapidly eliminated with 96% removal ratio in 10 min. Meanwhile, BC catalyst performed good stability and reusability. In addition, remarkable removal performance within 40 min (>94%) could be achieved in a wide range of pH (3.0–11.0). Through series characterizations, it was found that 700 °C was the critical pyrolysis temperature to prepare material with excellent property mainly attributing to large specific surface area (SSA), followed by high defect structure and rich C–O. It was speculated that radical pathway mainly especially surface-bounded radicals (SO 4 •−、•OH、O 2 −•) worked in the degradation of AO7. Specifically, abundant and typical oxygen-containing functional groups (OFGs) and defect structure catalytic sites of BC enhanced PDS activation. In addition, various radicals participated the whole degradation processes, such as the cleavage of azo bond (-N N-), hydroxylation, deamination and desulfurization. [Display omitted] • 700 °C was the critical temperature for preparing excellent catalyst of peroxydisulfate. • Large SSA (542.88 m2 g−1) was mainly accounted for the generation of radicals. • Surface-bounded radicals (SO 4.•−、•OH、O 2 −•) were responsible for AO7 degradation. • AO7 degradation contains –N N- break, hydroxylation, deamination and desulfurization. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungus (AMF) can enhance plant growth and resistance to toxicity produced by heavy metals (HMs), affect the bioavailability of HMs in soil and the uptake of HMs by plants, and thus has been emerged as the most prominent symbiotic fungus for contribution to phytoremediation. A greenhouse pot experiment was conducted to assess the effect of Glomus versiforme BGC GD01C (Gv) on the growth and Cd accumulation of Cd-hyperaccumulator Solanum nigrum in different Cd-added soils (0, 25, 50, 100 mg Cd kg −1 soil). Mycorrhizal colonization rates were generally high (from 71% to 82%) in Gv-inoculated treatments at all Cd levels. Gv colonization enhanced soil acid phosphatase activity, and hence elevated P acquisition and growth of S. nigrum at all Cd levels. Moreover, the presence of Gv significantly increased DTPA-extractable (phytoavailable) Cd concentrations in 25 and 50 mg Cd kg −1 soils, but did not affect phytoavailable Cd in 100 mg Cd kg −1 soil. Similarly, inoculation with Gv significantly increased Cd concentrations of S. nigrum in 25 and 50 mg Cd kg −1 soils, but decreased Cd concentrations of the plants in 100 mg Cd kg −1 soil. Overall, inoculation with Gv greatly improved the total Cd uptakes in all plant tissues at all Cd levels. The present results indicated that S. nigrum associated with Gv effectively improved the Cd uptake by plant and would be a new strategy in microbe-assisted phytoremediation for Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Highlights: [•] This is a first report about microbe-assisted Cd phytoextraction by Amaranthus species. [•] Rahnella sp. JN27 is an efficient PGP entophytic bacterium. [•] Strain JN27 showed very high ability in Cd tolerance and Cd mobilization. [•] Strain JN27 enhanced growth and Cd uptake by Amaranthus hypochondriacus and Amaranthus mangostanus. [•] Strain JN27 could successfully re-colonized in root interior of A. hypochondriacus. [ABSTRACT FROM AUTHOR]