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Rechargeable zinc-air batteries (ZABs) are regarded as a remarkably promising alternative to current lithium-ion batteries, addressing the requirements for large-scale high-energy storage. Nevertheless, the sluggish kinetics involving oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) hamper the widespread application of ZABs, necessitating the development of high-efficiency and durable bifunctional electrocatalysts. Here, we report oxygen atom-bridged Fe, Co dual-metal dimers (FeOCo-SAD), in which the active site Fe-O-Co-N6 moiety boosts exceptional reversible activity toward ORR and OER in alkaline electrolytes. Specifically, FeOCo-SAD achieves a half-wave potential (E1/2) of 0.87 V for ORR and an overpotential of 310 mV at a current density of 10 mA cm-2 for OER, with a potential gap (ΔE) of only 0.67 V Meanwhile, FeOCo-SAD manifests high performance with a peak power density of 241.24 mW cm-2 in realistic rechargeable ZABs. Theoretical calculations demonstrate that the introduction of an oxygen bridge in the Fe, Co dimer induced charge spatial redistribution around Fe and Co atoms. This enhances the activation of oxygen and optimizes the adsorption/desorption dynamics of reaction intermediates. Consequently, energy barriers are effectively reduced, leading to a strong promotion of intrinsic activity toward ORR and OER. This work suggests that oxygen-bridging dual-metal dimers offer promising prospects for significantly enhancing the performance of reversible oxygen electrocatalysis and for creating innovative catalysts that exhibit synergistic effects and electronic states. [ABSTRACT FROM AUTHOR]

The environmental transformations of nanomaterials are correlated with their behaviors and ecological risks. The applications of single-layer molybdenum disulfide (SLMoS2) have rapidly developed in environmental fields, but the potential transformations and biological effects of SLMoS2 remain largely unknown. This study revealed that humic acid (HA, over 10 mg/L) induced the scrolling of SLMoS2 with light irradiation over a 56-day incubation. The colloidal stability of SLMoS2 increased, and the aggregation ratio decreased from 0.59 ± 0.07 to 0.08 ± 0.01 nm/min after HA hybridization. Besides, compared with pristine SLMoS2, the chemical dissolution rate of SLMoS2 was up to 4.6-fold faster with HA exposure. These results demonstrate that HA affects the environmental fate and transformations of SLMoS2. SLMoS2-HA possessed a significantly widened direct band gap (2.06 eV) compared with that of SLMoS2 (1.8 eV). SLMoS2 acted as an electronic acceptor from HA, resulting in the separation of electron-hole pairs. Consequently, SLMoS2-HA exhibited stronger peroxidase-like catalytic activity, which was approximately 2-fold higher than that of SLMoS2. Moreover, the morphology and layered structure of SLMoS2 changed, and the damage SLMoS2 inflicted on microalgae was significantly reduced. This work provides insights into the behaviors and related biological risks of SLMoS2 in aqueous environments. [ABSTRACT FROM AUTHOR]

The interactions between nanomaterials and plants have attracted increasing attention. However, the systemic stress and recovery patterns of plants in response to nanomaterials and the connections between the molecular responses and the phenotypes remain unclear. Herein, rice was exposed to graphene oxide (GO) nanosheets at 0.01-1.0 mg/L for 7 days under hydroponic exposure, followed by a 7-day post exposure (GO-free). The significant upregulation (p < 0.05) of phenylalanine metabolism, secondary metabolism, and heme peroxidase reflected the stress and recovery patterns of rice roots exposed to GO. GO triggered 27% and more than 50% decreases in hydraulic conductivity and aquaporin gene expression (PIP1-3 and PIP2-2), respectively. The uptake of GO was mediated by aquaporin inhibition. Nanomaterial biotransformation reflected the potential for rice roots to adapt to GO stress. Oxidative stress, especially the downregulation of class III peroxidase mRNAs, were suppressed by GO. Lateral root inhibition, primary root growth, and cell wall synthesis, as forms of resistance to GO stress, were related to the significant (p < 0.05) downregulation of salicylic acid and lignin biosynthesis, as well as the upregulation of jasmonic acid and laccases. The present study helps elucidate the molecular and phenotypic responses of plants to nanomaterials, which are closely linked to their environmental risk assessment. [ABSTRACT FROM AUTHOR]

The performance optimization of isolated atomically dispersed metal active sites is critical but challenging. Here, TiO2@Fe species-N-C catalysts with Fe atomic clusters (ACs) and satellite Fe-N4 active sites were fabricated to initiate peroxymonosulfate (PMS) oxidation reaction. The AC-induced charge redistribution of single atoms (SAs) was verified, thus strengthening the interaction between SAs and PMS. In detail, the incorporation of ACs optimized the HSO5 -oxidation and SO5 ·-desorption steps, accelerating the reaction progress. As a result, the Vis/TiFeAS/PMS system rapidly eliminated 90.81% of 45 mg/L tetracycline (TC) in 10 min. The reaction process characterization suggested that PMS as an electron donor would transfer electron to Fe species in TiFeAS, generating 1O2. Subsequently, the hVB + can induce the generation of electron-deficient Fe species, promoting the reaction circulation. This work provides a strategy to construct catalysts with multiple atom assembly-enabled composite active sites for high-efficiency PMS-based advanced oxidation processes (AOPs). [ABSTRACT FROM AUTHOR]

Canola (Brassica napus) is one of the most economically important oilseed crops in Canada. Fusarium seedling blight is a root disease with the potential to cause severe yield reductions in canola. Fusarium spp. are commonly isolated root pathogens from fields in Alberta. Fusarium infection can also cause root rot in adult plants. In this study, 128 isolates identified as Fusarium spp. were recovered from field soils in central Alberta and from the roots of diseased canola plants with typical Fusarium seedling blight symptoms. Six species of Fusarium were identified, with Fusarium acuminatum as the predominant species (57 of 128 isolates, 44.5%). Phylogenetic analyses based on the translation elongation factor 1-α and the internal transcribed spacer sequence data were used for evaluation of genetic variations, and also used for Fusarium spp. identification in combination with morphological characteristics and polymerase chain reaction-based analyses. Based on disease ratings in pathogenicity tests, six isolates of F. avenaceum showed high aggressiveness on canola. Also, the aggressiveness varied within all Fusarium spp. No correlation was observed between aggressiveness and the geographic origin of the isolates. [ABSTRACT FROM AUTHOR]

It is well known that graphene (G) induces nanotoxicity towards living organisms. Here, a novel and biocompatible hydrated graphene ribbon (HGR) unexpectedly promoted aged (two years) seed germination. HGR formed at the normal temperature and pressure (120 days hydration), presented 17.1% oxygen, 0.9% nitrogen groups, disorder-layer structure, with 0.38 nm thickness ribbon morphology. Interestingly, there were bulges around the edges of HGR. Compared to G and graphene oxide (GO), HGR increased seed germination by 15% root differentiation between 52 and 59% and enhanced resistance to oxidative stress. The metabonomics analysis discovered that HGR upregulated carbohydrate, amino acid, and fatty acids metabolism that determined secondary metabolism, nitrogen sequestration, cell membrane integrity, permeability, and oxidation resistance. Hexadecanoic acid as a biomarker promoted root differentiation and increased the germination rate. Our discovery is a novel HGR that promotes aged seed germination, illustrates metabolic specificity among graphene-based materials, and inspires innovative concepts in the regulation of seed development [ABSTRACT FROM AUTHOR]

The article focuses on the health and ecosystem risks of graphene. It discusses several properties of graphene that determines risks including size-size distribution of graphene, corrugation in cell adhesion and pi-bonds inducing nonspecific binding. It highlights the in vitro and in vivo application of tissue engineering devices, electrical sensors and anticancer drugs. It highlights several health risks of graphene including damage of mucus, skin permeation and cell vision.

A mixture of five commonly used pharmaceuticals and personal care products (PPCPs) was degraded using a new combined catalyst under visible light irradiation. Scanning electron microscopy and X-ray diffraction analysis revealed that the combined catalyst was composed of copper-plating iron doped Cu20 (FeCu/Cu20). Compared with the Fe/C inner micro-circuit, the electric currents flowing between Cu and Fe increase the speed of anodic Fe dissolution. Moreover, due to the photochemical properties, Cu20 can accelerate the PPCPs degradation processes under the irradiation of visible light. In addition, shaking increased the dissolved oxygen concentration in the solution, which not only preconditioned the photo-catalysis reaction, but also set the stage for Fe reduction. According to the experimental results, we propose the possible reaction mechanism of the reaction. [ABSTRACT FROM AUTHOR]

The adsorption and desorption behavior of tetracycline on an Alfisol and an Ultisol was investigated at varying soil/solution ratios (1:10, 1:50, and 1:100) and different cation types (CaCl2, KCl, and NaCl) and H2O using a batch equilibration experiment. Kinetic studies revealed that the adsorption of tetracycline on the two soils was rate limited, and the adsorption kinetics could be well described by the Elovich equation and exponent equation. Changes in the soil/solution ratio affected the relative equilibration time in the Ultisol, but there was no effect of the initial tetracycline concentration. The adsorption rate in the soils decreased as the soil/solution ratio increased from 1:50 to 1:10. The adsorption and desorption data on tetracycline in the two soils could be described by the Freundlich isotherm equation, with r values >0.952 under all experimental treatments. The Ultisol always had stronger adsorption (higher distribution coefficient [Kd] value) than the Alfisol under all experimental conditions. The Kd values decreased with increasing soil/solution ratios in the two tested soils at 1 or 1.25 mg L-1 of tetracycline; however, this trend did not occur at 25 mg L-1 of tetracycline. The adsorption isotherm had an S-type curve that changed into an L-type curve with decreasing soil/solution ratios from 1:10 to 1:100. The presence of cations in the soil solution, especially CaCl2, can significantly reduce the adsorption of tetracycline in soils. The presence of cations also significantly reduced the nonlinearity of the adsorption isotherms. [ABSTRACT FROM AUTHOR]

In most countries, sanitary landfill is nowadays the most common way to eliminate municipal solid wastes (MSWs). However, sanitary landfill generates large quantity of heavily polluted leachate, which can induce ecological risk and potential hazards towards public health and ecosystems. The application of advanced oxidation processes (AOPs) including ozone-based oxidation, Fenton oxidation, electrochemical oxidation, and other AOPs to treatment of landfill leachate was reviewed. The treatment efficiency in term of chemical oxygen demand (COD) of various AOPs was presented. Advantages and drawbacks of various AOPs were discussed. Among the AOPs reviewed, Fenton process should be the best choice, not only because it can achieve about 49∼89% of COD removal with COD ranging from 837 to 8894 mg/L, but also because the process is cost-effective and simple in technological aspect, there is no mass transfer limitation (homogeneous nature) and both iron and hydrogen peroxide are nontoxic. [ABSTRACT FROM AUTHOR]

A systematic investigation was conducted to screen for cadmium-hyperaccumulator from 54 species in 20 weed families using outdoor pot-culture experiment and small-scale field experiment. The results from the outdoor pot-culture experiment showed that Cd concentrations in the stems and leaves of Solanum nigrum L. growing in a soil spiked with 25 mg/kg Cd were up to 103.8 and 124.6 mg/kg (DW), respectively, which was greater than 100 mg/kg, minimum Cd concentration for a Cd-hyperaccumulator. The Cd enrichment factor (EF, concentration ratio in plant to soil) in shoots was as high as 2.68. Moreover, Cd accumulation in shoots was greater than that in roots (TF, concentration ratio in shoots to roots) and the plant biomass growth was not inhibited at the Cd concentrations tested compared with the control. The results of the small-scale field experiment also showed that the characteristics of Cd accumulation in S. nigrum were all consistent with the characteristics of Cd-hyperaccumulators. Thus S. nigrum can be classified as a Cd-hyperaccumulator. This work is important for further research in the areas of hyperaccumulators screening, and plant-tolerance physiology and evolution. It provides a patentable new plant species for phytoremediation of Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Previous field investigations and a pot-culture experiment treated with 0, 5, 10, and 20 mg kg-1 of reactive X-3B red dye (RRD), combined with chemical and statistical analyses, indicated that the amount of iron accumulated in seeds of soybean (Glycine max) and rice (Oryza sativa) and edible parts of watermelon (Citrullus Vulgaris Schrad) decreased with the increase in the amount of RRD added to various soils including burozem, aquorizem and krasnozem. There were significant negative relationships between the uptake of iron by the crops and the concentration of RRD added to the soils. Thus, chemical pollution of some organic dyes in agricultural soils may result in the deficiency of iron in crops. According to the extraction with 1.0 M NH4OAc solution and the determination of enzyme activity, the adverse effect inhibiting the uptake of iron in crops was chemical chelation and immobilization of iron with RRD. The activity of iron reductase was also greatly affected. [ABSTRACT FROM AUTHOR]

Joint effects of Cd and other heavy metals (Pb, Cu, Zn and As) on the growth and development of rice plants and the uptake of these heavy metals by rice were studied using the pot-culture method combined with chemical and statistical analyses. The re-suits showed that the growth and development of rice plants were strongly influenced by the doubie-element combined pollution. There was an average decrease In the height of rice plants of 4.0-5.0 cm, and grain yield was decreased by 20.0-30.0%, compared with the control. The uptake of Cd by rice plants was promoted due to the interactions between Cd and the other heavy metals added to the soil. The Cd concentration in roots, stems/leaves and seeds increased 31.6-47,7,16,7-61,5 and 79.6-78.6%, respectively. Due to interactions, uptake of Pb, Cu and Zn by roots and stems/leaves was inhibited, accumulation of Pb, Cu and Zn in seeds was increased, uptake of As by roots was promoted and uptake of As by stems/leaves was inhibited. In particular, the upward transporting ability of the heavy metals absorbed by rice plants was significantly increased. [ABSTRACT FROM AUTHOR]

Presents a study which investigates the sensitivities to marine pollution of marine organisms in the Zhoushan Sea area of China, through systematic collection of affected marine organisms. Marine ecosystem in Zhoushan Sea Waters; Materials and methods; Discussion of results.

A review of the literature published in 2016 on topics relating to water reclamation and reuse is summarized. The review is divided into the following sections: 1) General: monitoring and assessment, social awareness and acceptance, and energy and resources recovery; 2) Treatment technology: integrated technologies, membrane treatment, reactors, WSPs, disinfection, and others; 3) Planning and Management: modeling, LCA, GHG emission, and case studies. Much of the water treatment research focused on the integrated technologies and membrane treatment. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is an important green oxidant in the field of sewage treatment, and how to improve its activation efficiency and generate free radicals with stronger oxidation performance is a key issue in current research. Herein, we synthesized a Cu-doped α-Fe2O3 catalyst (7% Cu-Fe2O3) for activation of H2O2 under visible light for degradation of organic pollutants. The introduction of a Cu dopant changed the d-band center of Fe closer to the Fermi level, which enhanced the adsorption and activation of the Fe site for H2O2, and the cleavage pathway of H2O2 changed from heterolytic cleavage to homolytic cleavage, thereby improving the selectivity of ⋅OH generation. In addition, Cu doping also promoted the light absorption ability of α-Fe2O3 and the separation of hole-electron pairs, which enhanced its photocatalytic activities. Benefiting from the high selectivity of ⋅OH, 7% Cu-Fe2O3 exhibited efficient degradation activities against ciprofloxacin, the degradation rate was 3.6 times as much as that of α-Fe2O3, and it had good degradation efficiency for a variety of organic pollutants. [ABSTRACT FROM AUTHOR]

The environmental behaviors and risks associated with graphene have attracted considerable attention. However, the fundamental effects of ambient water and visible-light irradiation on the properties and toxicity of graphene remain unknown. This work revealed that hydration and irradiation result in the transformation of large-sheet graphene to long-ribbon graphene. The thickness of the treated graphene decreased, and oxides were formed through the generation of singlet oxygen. In addition, hydration and irradiation resulted in greater disorder in the graphene structure and in the expansion of the d-spacing of the structure due to the introduction of water molecules and modifications of the functional groups. Oxidative modifications with two-stage (fast and low) kinetics enhanced the number of negative surface charges on the graphene and enhanced graphene aggregation. The above property alterations reduced the nanotoxicity of graphene to algal cells by reducing the generation of reactive oxygen species, diminishing protein carbonylation and decreasing tail DNA. A comparative study using graphene oxide suggested that oxidative modifications could play an important role in inhibiting toxicological activity. This study provides a preliminary approach for understanding the environmental behaviors of graphene and avoids overestimating the risks of graphene in the natural environment. [ABSTRACT FROM AUTHOR]

The adsorption of chlorimuron-ethyl in two typical northeastern Chinese soils before and after removal of organic matter and removal of organic matter plus iron/aluminum oxides was investigated using batch equilibrium methods, and the effect of pH on the adsorption was also evaluated. The adsorption kinetics were fitted well with the Elovich and pseudo-second-order kinetic models (R² = 0.973-0.985) and the adsorption isotherms conformed to the Linear, Freundlich, and Langmuir models (R² > 0.963). The mineral fraction appeared to dominate adsorption of chlorimuron-ethyl in brown earth (BE; Alfisols), while organic matter was the major component for the adsorption in black soil (BS; Moliisols). The adsorption of chlorimuron-ethyl in the original and treated soils all decreased with increasing pH. Moreover, the effect of pH on the adsorption of chlorimuron-ethyl in soil minerals was stronger than that in organic matter at acidic conditions. [ABSTRACT FROM AUTHOR]

Aptamers are a new class of single-stranded DNA/RNA molecules selected from synthetic nucleic acid libraries for molecular recognition. Our group reports a novel aptamer column for the removal of trace (ng/L) pharmaceuticals in drinking water. In this study, cocaine and diclofenac were chosen as model molecules to test the aptamer column which presented high removal capacity, selectivity, and stability. The removal of pharmaceuticals was as high as 88-95%. The data of adsorption were fitted with Langmuir isotherm and a pseudo-second-order kinetic model. A thermodynamic experiment proved the adsorption processes were exothermic in spontaneity. The kinetics of aptamer was composed of three steps: activation, binding, and hybridization. The first step was the rate-controlling step. The adsorption system was divided into three parts: kinetic, mixed, and thermodynamic zones from 0% to 100% binding fraction of aptamer. Furthermore, the aptamer column was reusable and achieved strong removal efficiency from 4 to 30 °C at normal cation ion concentration (5-100 mg/L) for multipollutants without cross effects and secondary pollution. This work indicates that aptamer, as a new sorbent, can be used in the removal of persistent organic pollutants, biological toxins, and pathogenic bacteria from surface, drinking, and ground water. [ABSTRACT FROM AUTHOR]

Protein corona formation is critical for the design of ideal and safe nanoparticles (NPs) for nanomedicine, biosensing, organ targeting, and other applications, but methods to quantitatively predict the formation of the protein corona, especially for functional compositions, remain unavailable. The traditional linear regression model performs poorly for the protein corona, as measured by R2 (less than 0.40). Here, the performance with R2 over 0.75 in the prediction of the protein corona was achieved by integrating a machine learning model and meta-analysis. NPs without modification and surface modification were identified as the two most important factors determining protein corona formation. According to experimental verification, the functional protein compositions (e.g., immune proteins, complement proteins, and apolipoproteins) in complex coronas were precisely predicted with good R² (most over 0.80). Moreover, the method successfully predicted the cellular recognition (e.g., cellular uptake by macrophages and cytokine release) mediated by functional corona proteins. This workflow provides a method to accurately and quantitatively predict the functional composition of the protein corona that determines cellular recognition and nanotoxicity to guide the synthesis and applications of a wide range of NPs by overcoming limitations and uncertainty. [ABSTRACT FROM AUTHOR]

The electrical conductivity (EC) of soil is generally measured after soil extraction, so this method cannot represent the in situ EC of soil (e.g., EC of soils with different moisture contents) and therefore lacks comparability in some cases. Using a resistance measurement apparatus converted from a configuration of soil microbial fuel cell, the in situ soil EC was evaluated according to the Ohmic resistance (Rs) measured using electrochemical impedance spectroscopy. The EC of soils with moisture content from 9.1% to 37.5% was calculated according to Rs. A significant positive correlation (R2 = 0.896, p < 0.01) between the soil EC and the moisture content was observed, which demonstrated the feasibility of the approach. This new method can not only represent the actual soil EC, but also does not need any pretreatment. Thus it may be used widely in the measurement of the EC for soils and sediments. [ABSTRACT FROM AUTHOR]

From eastern to western areas, per- and polyfluoroalkyl substances (PFASs) were detected at substantial levels in the outdoor dust across mainland China Urban samples generally showed higher levels compared with those of rural samples. Compared with neutral PFASs, ionizable PFASs (C4-Cl2 perfluoroalkyl carboxylic acids and C4/C8 perfluoroalkyl sulfonic acids) were more abundant, with the highest total concentration up to 1.6 x 10² ng/g and perfluorooctanoic acid (PFOA) being a predominant analogue. Fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphoric acid diesters (DiPAPs) were both detected in most samples with total concentrations of 0.12-32 and 0.030-20 ng/g, respectively. Perfluorooctane sulfonamidoethanols/sulfonamides (FOSE/As) were detected at low frequencies (<30%). In addition to partitioning to organic moiety, specific adsorption onto mineral particles can be important for PFASs to bind onto outdoor dust, especially for short-chain ionizable PFASs. The eastern plain areas were characterized by a higher contribution of long-chain ionizable PFASs; whereas the western high plateau areas were characterized by the dominating contribution of short-chain analogues. The difference suggests that the long-range atmospheric transport potential of PFASs from source regions to the inland is probably limited by die increase in altitude, and different sources from adjacent regions may influence the western border area of China. [ABSTRACT FROM AUTHOR]

To study the uptake pathways of 3 main hexabromocyclododecane diastereoisomers (α-, Ś-, and γ-HBCDs) in wheat, four closed chambers were designed to expose wheat to HBCDs via air and/or soil for 4 weeks. The results showed that HBCDs could be absorbed by wheat both via root from soil and via leaf from air. The Rt values (ratio of HBCDs from root-to-leaf translocation to the total accumulation in leaves) ranging from 14.4 to 29.8% suggested that acropetal translocation within wheat was limited. A negative linear relationship was found between log Rt and log Kow of the HBCD diastereoisomers (p < 0.05). The bioconcentration factors (BCFs, (αg/g wheat tissues)/(μg/g soil)) were in the order α- > β- > γ-HBCD in wheat roots and stems, being negatively related to their Kow values. No such correlation was found in leaves, where the HBCDs came mainly from air distribution. The results of enantiomeric fractions indicated that the (-)-enantiomer of α- and γ-HBCDs and the (+)-β-enantiomer were selectively accumulated. Furthermore, β- and γ-HBCDs were transformed to α-HBCD in the wheat, with 0.309-4.80% and 0.920-8.40% bioisomerization efficiencies at the end of the experiment, respectively, being the highest in leaves. Additionally, no isomerization product from α-HBCD was found. [ABSTRACT FROM AUTHOR]

Despite the frequent detection of benzotriazoles (BTRs) and benzothiazoles (BTHs) in groundwater and surface-water environments, knowledge on their occurrence and profile in tap water is still scarce. This study demonstrates widespread occurrence of these compounds in tap water from 51 major cities in China, which have ranges of

Nanomaterial oxides are common formations of nanomaterials in the natural environment. Herein, the nanotoxicology of typical graphene oxide (GO) and carboxyl single-walled carbon nanotubes (C-SWCNT) was compared. The results showed that cell division of Chlorella vulgaris was promoted at 24 h and then inhibited at 96 h after nanomaterial exposure. At 96 h, GO and C-SWCNT inhibited the rates of cell division by 0.08-15% and 0.8-28.3%, respectively. Both GO and C-SWCNT covered the cell surface, but the uptake percentage of C-SWCNT was 2-fold higher than that of GO. C-SWCNT induced stronger plasmolysis and mitochondrial membrane potential loss and decreased the cell viability to a greater extent than GO. Moreover, C-SWCNT-exposed cells exhibited more starch grains and lysosome formation and higher reactive oxygen species (ROS) levels than GO-exposed cells. Metabolomics analysis revealed significant differences in the metabolic profiles among the control, C-SWCNT and GO groups. The metabolisms of alkanes, lysine, octadecadienoic acid and valine was associated with ROS and could be considered as new biomarkers of ROS. The nanotoxicological mechanisms involved the inhibition of fatty acid, amino acid and small molecule acid metabolisms. These findings provide new insights into the effects of GO and C-SWCNT on cellular responses. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a widely used carbonaceous nanomaterial. To date, the influence of natural organic matter (NOM) on GO toxicity in aquatic vertebrates has not been reported. During zebrafish embryogenesis, GO induced a significant hatching delay and cardiac edema. The intensive interactions of GO with the chorion induces damage to chorion protuberances, excessive generation of ·OH, and changes in protein secondary structure. In contrast, humic acid (HA), a ubiquitous form of NOM, significantly relieved the above adverse effects. HA reduced the interactions between GO and the chorion and mitigated chorion damage by regulating the morphology, structures, and surface negative charges of GO. HA also altered the uptake and deposition of GO and decreased the aggregation of GO in embryonic yolk cells and deep layer cells. Furthermore, HA mitigated the mitochondrial damage and oxidative stress induced by GO. This work reveals a feasible antidotal mechanism for GO in the presence of NOM and avoids overestimating the risks of GO in the natural environment. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is widely used in various fields and is considered to be relatively biocompatible. Herein, "indirect" nanotoxicity is first defined as toxic amplification of toxicants or pollutants by nanomaterials. This work revealed that GO greatly amplifies the phytotoxicity of arsenic (As), a widespread contaminant, in wheat, for example, causing a decrease in biomass and root numbers and increasing oxidative stress, which are thought to be regulated by its metabolisms. Compared with As or GO alone, GO combined with As inhibited the metabolism of carbohydrates, enhanced amino acid and secondary metabolism and disrupted fatty acid metabolism and the urea cycle. GO also triggered damage to cellular structures and electrolyte leakage and enhanced the uptake of GO and As. Co-transport of GO-loading As and transformation of As(V) to high-toxicity As(III) by GO were observed. The generation of dimethylarsinate, produced from the detoxification of inorganic As, was inhibited by GO in plants. GO also regulated phosphate transporter gene expression and arsenate reductase activity to influence the uptake and transformation of As, respectively. Moreover, the above effects of GO were concentration dependent. Given the widespread exposure to As in agriculture, the indirect nanotoxicity ofGOshould be carefully considered in food safety. [ABSTRACT FROM AUTHOR]

Graphene-related research has intensified rapidly in a wide range of disciplines, but few studies have examined ecosystem risks, particularly phytotoxicity. This study revealed that graphene significantly inhibits the number of wheat roots and the biosynthesis of chlorophyll, and altered the morphology of shoots. Humic acid (HA), a ubiquitous form of natural organic matter, significantly (P < 0.05) relieved this phytotoxicity and recovered the sharp morphology of shoot tips. Both graphene and graphene-HA were transferred from wheat roots to shoots and were found in the cytoplasms and chloroplasts. HA increased the disordered structure and surface negative charges, and reduced the aggregation of graphene. HA enhanced the storage of graphene in vacuoles, potentially indicating an effective detoxification path. The content of cadaverine, alkane, glyconic add, and aconitic acid was upregulated by graphene, greatly contributing to the observed phytotoxicity. Conversely, inositol, phenylalanine, phthalic acid, and octadecanoic acid were up-regulated by g raphene -HA The metabolic pathway analysis revealed that the direction of metabolic fluxes governed nanotoxicity. This work presents the innovative concept that HA acts as a natural antidote of graphene by regulating its translocation and metabolic fluxes in vivo. This knowledge is critical for avoiding tire overestimation of nanomaterial risks and can be used to control nanomaterial contamination. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH- transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m2, which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m2) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited. [ABSTRACT FROM AUTHOR]

The occurrence of antibiotics and antibiotic resistance genes (ARGs) was quantified in water and sediment samples collected from a 72 km stretch of the Haihe River, China. Tetracycline resistance genes (tetW, tetQ, tetQ, tetT, tetM, tetB, and tetS) were not detected by quantitative PCR in many samples. In contrast, sul1 and sul2 (coding for sulfonamide resistance) were present at relatively high concentrations in all (38) samples. The highest ARG concentrations detected were (7.8 ± 1.0) × 109 copies/g for sul1 and (1.7 ± 0.2) × 1011 copies/g for sul2, in sediment samples collected during the summer. The corresponding total bacterial concentration (quantified with a universal 16S-rDNA probe) was (33 ± 0.4) × 1012 cella/g. Sul1 and sul2 concentrations in sediments were 120-2000 times higher than that in water, indicating that sediments are an important ARG reservoir in the Haihe River. Statistical analysis indicated a positive correlation between the relative abundance of these ARCs (i.e., sul1/16S-rDNA and sul2/16S-rDNA) and the total concentration of sulfamethoxazole, sulfadiazine, plus sulfachlororyridazine, suggesting that sulfonamides exerted selective pressure for these ARGs. A class 1 integron was implicated in the propagation of sul1. Overall, the widespread distribution of sulfonamide ARGs underscores the need to better understand and mitigate their propagation in the environment and the associated risks to public health. [ABSTRACT FROM AUTHOR]

The combined effects of the porous structure, acidity, and ion-exchange properties of zeolites and the structures of the degradation products of nitrosamines in aqueous solution on adsorption were evaluated. The degradation products of nitrosamines including the aliphatic low-molecular-weight amines methylamine, dimethylamine, ethylamine, and diethylamine and the aromatic amine aniline all exhibited significant adsorption affinities to HZSM-5 zeolites, and aliphatic low-molecular-weight amines exhibited much greater adsorption affinities to HY zeolite than to NaY and HZSM-5 zeolites, but aromatic amines exhibited little adsorption affinity to HY and NaY zeolites. The results of the pH-dependency experiments further indicated that the acidity and polarity of the adsorbates and the acidity of the adsorbents play a combinational role in determining the significance of the adsorption interactions between low-molecular-weight amines in aqueous solution and zeolites. We propose that the acid-base and electrostatic interactions and the shape-selective adsorption properties of HZSM-5 zeolites are all responsible for the adsorption of aliphatic and aromatic low-molecular-weight amines on HZSM-5 zeolites in aqueous solution and that the acid-base and electrostatic interactions and ion-exchange properties of Y-type zeolites all contribute to the adsorption of aliphatic amines on Y-type zeolites in aqueous solution. The findings of the present study might have significant implications for the removal of low-molecular-weight amines from aqueous solutions and the thorough control of N-nitrosamines in water with zeolites. [ABSTRACT FROM AUTHOR]