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Biomass-derived porous carbon materials are potential adsorbents for VOCs. In this work, biomass-derived nitrogen-doped hierarchical porous carbons (NHPCs) were synthesized by a one-step pyrolysis activation combined with nitrogen doping method from several biomass wastes (corn straw, wheat stalk, bamboo, pine, and corncob). NHPCs have a hierarchical porous structure with micro-meso-macropores distribution, nitrogen doping, large specific surface area, and pore volume. The corncob derived carbon (NHPC-CC) has the best activation result as analyses showed that a lower ash content and higher total cellulose composition content of the biomass result in a better pore activation effect. Single and multi-component dynamic adsorption tests of typical VOCs (benzene, toluene, and chlorobenzene) were conducted on NHPCs in laboratory conditions (∼500 ppm). Promising VOC adsorption capacity and great adsorption kinetics with low mass transfer resistance were found on NHPCs. Correlation analysis showed that the high VOC adsorption capacity and great adsorption kinetics can be attributed to the large surface area of micro-mesopores and the mass transfer channels provided by meso-macropores respectively. The competitive dynamic adsorption tests revealed that the VOC with lower saturated vapor pressure has more adsorption sites on the surface of micro-mesopores and stronger adsorption force, which results in the higher adsorption capacity and desorption caused by substitution reaction in VOCs competitive adsorption process. In detail, the process of toluene and chlorobenzene competitive adsorption was described. Besides, well recyclability of NHPC-CC was revealed as the VOCs adsorption capacity reductions were less than 10% after four adsorption-desorption cycles. All studies showed that the NHPC-CC could be potential adsorbent for VOCs in industrial process.

The graphite-phase carbon nitride (g-C

Standard reference materials (SRMs) have been commonly used to perform quality assurance and quality control (QA/QC) in soil total metal concentration analyses or bioaccessibility assessment. In this study, 10 experimenters from 4 laboratories determined bioaccessibility of lead (Pb) in 4 widely-used SRMs (NIST 2710a, NIST 2587, BGS 102, and GBW 07405). Based on the gastric phase (GP) of the unified BARGE bioaccessibility method (UBM) and the Solubility Bioavailability Research Consortium procedure (SBRC), Pb bioaccessibility in SRMs was compared within and between laboratories to assess their intra-laboratory repeatability and inter-laboratory reproducibility. Lead bioaccessibility was 14.1 ± 2.44%-101 ± 2.48% in the 4 SRMs. The values were in vivo validated based on a mouse model in previous studies (R

Short-chain (SC) and medium-chain (MC) chlorinated paraffins (CPs) are found widely in the environment. Little research into air-soil exchange of SCCPs and MCCPs has been performed. In this study, CP concentrations, congener group profiles, and air-soil exchange in a typical contaminated area were investigated. A total of 10 soil samples and 10 air samples were collected from Zhoushan, an island in China. The samples were analyzed by two-dimensional gas chromatography electron capture negative ionization mass spectrometry. The SCCP and MCCP concentrations in the soil samples were 72-3842 and 117-8819 ng/g, respectively, and the SCCP and MCCP concentrations in the air samples were 57-208 and 1.8-25 ng/m

Most of the commonly used traditional permeable reactive barrier (PRB) fillers have many drawbacks, such as poor retention of hydraulic conductivity, high cost, and a complex preparation process. Porous geopolymers (PGPs) with controllable pore structures could circumvent these drawbacks owing to their high adsorption capacity, cost-effective synthesis, and good chemical stability. In this study, based on our previous research, the "foaming-liquid film" balance control method was proposed and used to fabricate three PGPs with gradient pore connectivity. The influence of pore structure on the Pb

The cumulative exposure to metals affects cardiac conduction, and the effect of polymetallic exposure on heart rate in children is unknown. To evaluate the relationship between cumulative exposure to metal mixtures and heart rate among Chinese preschoolers, the determination of urinary 24 metals was processed by high-resolution inductively coupled plasma-mass spectrometry. Heart rate was recorded when measuring blood pressure after resting 5 min or longer. As a method to compute the Environmental risk score (ERS) according to heart rate under heavy metal mixtures, adaptive elastic net (AENET) with 299 predictors which were formed by the combination of main effects, squared terms, and pairwise interactions of heavy metals with a total number of 23, 23, 253 respectively. To further assess the associations between ERS and heart rate, regression analyses were performed with complex survey designs. The construction of ERS under heart rate-related metal mixtures was returned by AENET in according to 11 main effects (tin, arsenic, zinc, iron, titanium, vanadium, nickel, manganese, cobalt, copper and chromium) and 2 squared terms (tungsten and rubidium). A high correlation was monitored between the alteration of ERS in the study population and heart rate (β = 1.030, 95% CI: 0.730 - 1.330 in 1239; β = 1.085, 95% CI: 0.777 - 1.393 in 1061). Significant associations of ERS with higher heart rates were also pointed out (Ps 0.05). Our study elucidates the association of the cumulative exposure of heavy metals as mixtures and heart rate among Chinese preschoolers. Further research is obliged to corroborate these findings in longitudinal studies.

The disposing of municipal solid waste incineration(MSWI) fly ashes containing dioxins is an intractable problems. Co-sintering is one of the most ideal methods to dispose MSWI fly ash, because it not only degrades the dioxins but also makes it possible to re-utilize MSWI fly ashes. In the present study, MSWI fly ash(FA) and water washed MSWI fly ash(WFA) were added into the sinter raw mixture in a lab-scale sintering pot. Different effects of fly ash and water washed fly ash on emission characteristics of dioxins were studied, and possible pathways to form dioxins were discussed in detail. During co-sintering, at least 88.9%, 99.1% of dioxins brought in by FA, WFA was decomposed, respectively, and re-synthesis with a significant distribution characteristic of dioxins originated from sintering process. In the preheating and dry zone, the recombination and condensation reaction of precursors were the main formation pathways of 2,3,7,8-PCDDs in the sintering process and 2,3,7,8-PCDFs were formed by de novo synthesis. In addition, the resynthesis process was affected by chlorine and calcium brought in by fly ash. Sufficient chlorine boosted the chlorination of reactants while calcium increased the residence time, causing the emission concentration of toxic dioxins and the adding ratio were nonlinearly dependent. Therefore, the maximum proportion of water washed MSWI fly ash that can be added into the sintering process was 0.5 wt.%. Besides, the possible pathways to form dioxins were proposed.

Trace anionic dyes in wastewater are difficult to be rapidly and efficiently removed because they are completely soluble and poorly biodegradable. Herein, a facile and environmentally friendly adsorbent was fabricated via the surface functioned SiO2 with abundant amine groups of polyethyleneimine (PEI). The structural characterization indicated that PEI was successfully immobilized on the SiO2 surface. The adsorption performance of SiO2-PEI was evaluated using acid orange II (AOII) as model pollutant. The adsorption of AOII on SiO2-PEI displayed high removal rates in the pH range of 2.0–9.0, and exhibited ultrafast removal (99.1% removal rate at 10 min). The adsorption behavior fitted well with the Langmuir isotherm and pseudo-second-order kinetic model, and the maximum uptake capability of AOII was higher than 705.3 mg/g. The excellent adsorption capacity of AOII on SiO2-PEI mainly relied on the electrostatic attraction between the sulfonic acid group of AOII and amine group of PEI in the adsorption process. Additionally, other anionic dyes like acid fuchsin and direct sky blue 5B could also be fast and efficiently removed by SiO2-PEI. This work is expected to open new possibilities for the ultrafast removal of anionic dye pollutants.

Liquid catalytic hydrogenation is a green and cost-effective technique for the reductive removal of pollutants in water. Supported noble metals are the most frequently used catalysts in liquid phase catalytic hydrogenation, whereas marked catalyst deactivation is commonly identified. In this study, we coated supported Pd catalyst on carbon nanotube (denoted as Pd/CNT) by different overcoatings (including SiO2, carbon and N-doped carbon) to prevent catalyst deactivation. The activities of the coated catalysts for liquid phase catalytic hydrogenation reduction of hexavalent chromium (Cr(VI)) differed with the overcoating properties. Negligible Cr(VI) conversion was observed on SiO2 coated Pd/CNT, while feasible Cr(VI) reduction was identified on carbon coated (denoted as Pd/CNT@C) and N-doped carbon coated catalysts (denoted as Pd/CNT@CN). Pd/CNT@CN exhibited a much higher catalytic activity than Pd/CNT@C, which was ascribed to the stronger Cr(VI) adsorption on CN overcoating. The catalytic activity of Pd/CNT@CN was positively correlated with the conductivity and hydrophilicity of CN overcoating, which could be optimized by varying carbonization temperature. Furthermore, Pd/CNT@CN retained its initial activity after ten consecutive catalyst cycles without any deactivation, whereas Pd/CNT only retained 8.2% of its initial activity, reflecting much higher catalytic stability of Pd/CNT@CN than Pd/CNT. The findings in the present study highlight that liquid catalytic reduction using Pd/CNT@CN as the catalyst is a highly stable and effective method to remove Cr(VI) in water.

Dietary intake is an important route of human exposure to chlorinated paraffins (CPs). Cup instant noodles are widely popular food and millions packet of instant noodles are consumed every year. To investigate the levels, congener groups, and health risk of SCCPs and MCCPs in each component of cup instant noodles, samples of nine common brands were collected and analyzed by comprehensive two dimensional gas chromatography coupled with mass spectrometry. The mean concentrations in the noodles were 1.2 × 103 ng/g wet weight (ww) (SCCPs) and 1.2 × 102 ng/g ww (MCCPs), the mean concentrations in the seasoning were 1.4 × 103 ng/g ww (SCCPs) and 1.3 × 102 ng/g ww (MCCPs), and the mean concentrations in the soup were 5.6 × 102 ng/L (SCCPs) and 5.4 × 102 ng/L (MCCPs). The SCCP to MCCP ratio were similar in the soup and soup container, which means CPs in the soup might be migrated from the soup container. Seasoning and noodles from the same brands have similar congener profiles of SCCPs and MCCPs, which may be raised from the manufacturing process or food packaging materials. The dominant SCCP congener groups were C10–11Cl6–7 in noodles and seasoning, and C10,13Cl6–7 in soup. The dominant MCCP congener groups were C14–15Cl6–7 in noodles and seasoning, and C14–15Cl6–7 in soup. A preliminary health risk assessment indicated that the current intakes of SCCPs and MCCPs through cup instant noodles in China did not pose a significant risk to human health.

Amphibians are often exposed to pulse pollution due to fluctuational inputs of pollutants in water. Traditional ecotoxicology research is mainly performed under constant exposure conditions, which is not consistent with the true environmental pollution. Frogs are sensitive to changes in water pollutants in pre-hibernation. Thus, to understand the toxicity difference to continuous and pulse exposure in environmental concentrations of Pb (100 μg/L), Pelophylax nigromaculatus adults were exposed to short-term treatments (8 days) in pre-hibernation. Individual mortality, intestinal anatomical structure, bacterial diversity, and metabolites were measured in a control group (CON), a Pb continuous treatment group (CEPb) and a Pb pulse treatment group (PEPb). The results showed that PEPb significantly increased individual mortality, compared to the control group and CEPb. PEPb induced pathological changes in the small intestinal tissues, such as mucosal erosion, swollen and distorted villi, large vacuoles, and the proliferation of goblet cells. In addition, PEPb altered the structure and diversity of intestinal bacteria, resulting in an increase in some pathogenic bacteria (e.g. Bacteroides and Ruminococcus) and a decrease in beneficial bacteria (e.g. Cetobacterium and Akkermansia). Both CEPb and PEPb significantly changed intestinal metabolites and metabolic pathways. Moreover, PEPb has a significant effect on the metabolism of amino acids by increasing the content of 5-Aminopentanoic acid, cis-4-Hydroxy-l-proline, Glycocholic acid, l-Alanine, and l-Isoleucine. We concluded that PEPb may lead to intestine impairment of P. nigromaculatus in pre-hibernation by inducing intestinal structural integrity destruction, bacterial imbalance, and metabolic dysfunction, resulting in a significant increase in mortality. The study provides new insights for understanding the intestinal responses of frogs to pulse metal exposure.

To understand how Cd in different fractions contributes to Cd bioaccessibility by in vitro assays, Cd bioaccessibility in 12 contaminated soils was determined by four assays (UBM, SBRC, IVG, and PBET) and correlated with different Cd fractions based on a sequential extraction scheme. The Cd bioaccessibility in the gastric phase (GP) was high (35–107%, averaging at 77%), implicating high risk to human health, while it decreased to 19–88% averaging at 47% in the intestinal phased (IP). From the GP to IP, the reduction of extractable Cd (0.45–48 mg kg−1) and Fe (118–3884 mg kg−1) showed significant correlation (R = 0.54–0.74) via UBM, SBRC, and IVG, suggesting co-precipitation with Fe and/or sorption onto Fe oxides maybe responsible for decrease in Cd bioaccessibility. Although Cd bioaccessibility varied among assays, their results show some consistency based on their correlation in the GP (R = 0.56–0.90) and IP (0.34–0.73, excluding UBM-IP and PBET-IP). Sequential extraction data show that Cd was primarily associated with the exchangeable fraction (E1; 7.05–72.9%, averaging 39.4%). The carbonate (C2; 6.86–44.8%, 21.9%) and Fe/Mn oxides fraction (F3; 12.5–53.6%, 28.2%) were similar, while organic (O4; 0.62–25.0%, 7.91%) and residual fraction (R5; 0.22–8.54%, 2.62%) were the lowest. Significant correlation (R = 0.59–0.88) between the first two fractions (E1+C2) and bioaccessible Cd suggest they were the main sources of bioaccessible Cd in those contaminated soils.

Seasonal changes in chemical compositions and source apportionment of PM

The instability and rapid consumption of H

Hypothyroidism is commonly associated with substantial adverse impacts on human health, and polybrominated diphenyl ether (PBDE), a kind of classic thyroid hormone disruptor, was speculated to be a potential environmental factor, but its effect on thyroxine metabolism has received little attention. In the present study, we investigated the role and mechanism of rno-miR-224-5p in deiodinase-mediated thyroxine metabolism in rats treated with 2,2',4,4'-tetrabromodiphenyl ether (BDE47), a predominant PBDE congener in humans. BDE47 decreased plasma triiodothyronine (T3) and thyroxine (T4) and increased reverse T3 (rT3) in the rats, and the expression of type 1 deiodinase (DIO1) and type 3 deiodinase (DIO3) increased in both the rats and H4-II-E cells. Rno-miR-224-5p was predicted to target dio1 instead of dio3, according to the TargetScan, miRmap.org and microRNA.org databases. Experiments showed that the rno-miR-224-5p level was decreased by BDE47 in a dose-dependent manner and confirmed that rno-miR-224-5p downregulated both DIO1 and DIO3 in the H4-II-E cells and in the rats, as determined using mimics and an inhibitor of rno-miR-224-5p. Furthermore, DIO1 was observed to be a direct functional target of rno-miR-224-5p, whereas DIO3 was indirectly regulated by rno-miR-224-5p via the phosphorylation of the MAPK/ERK (but not p38 or JNK) pathway. Reportedly, DIO1 and DIO3 act principally as inner-ring deiodinases and are responsible for the conversion of T4 to rT3, but not to T3, and the final clearance of thyroxine (mainly in the form of T2). Our results demonstrated that BDE47 induced low levels of T3 conversion through DIO1 and DIO3, which were regulated by rno-miR-224-5p. The findings suggest a novel additional mechanism of PBDE-induced thyroxine metabolism disorder that differs from that of PBDEs as environmental thyroid disruptors.

Three functional zones, namely the industrial (IND), the agricultural (AGR), and the grassland (GRA) areas from Inner Mongolia (a remote province in northern China), were selected to evaluate the levels and distributions of PBDEs and the risks posed to local humans. PBDEs concentrations in surface soils and tree bark were detected and the air levels were estimated based on bark measurements. The total concentrations (∑8PBDEs) of BDE-28, -47, −100, −99, −154, −153, −183, and −209 in soils were 1.71–64.9 ng/g dry weight (d.w.), 0.720–4.08 ng/g d.w., and 0.604–3.76 ng/g d.w. in the IND, AGR and GRA areas respectively. The average total concentrations in bark and air were 0.792 ng/g d.w. and 0.125 ng/m³ in the AGR areas respectively, which were lower than those (1.69 ng/g d.w. in the bark and 0.476 ng/m³ in the air) in the IND areas. BDE-209 was the dominant congener, consistent with DeBDE being the dominant commercial products used in China. However, except for BDE-209, BDE-28 and BDE-47 in the AGR and GRA areas averagely contributed about half of the total PBDEs concentrations in soils. BDE-28 concentrations in the bark samples of the AGR areas were significantly higher (p

ZnO nanoparticles is one of the most used materials in a wide range including antibacterial coating, electronic device, and personal care products. With the development of nanotechnology, ecotoxicology of ZnO nanoparticles has been received increasing attention. To assess the phototoxicity of ZnO nanoparticles in aquatic ecosystem, microcosm experiments were conducted on Populus nigra L. leaf litter decomposition under combined effect of ZnO nanoparticles and visible light radiation. Litter decomposition rate, pH value, extracellular enzyme activity, as well as the relative contributions of fungal community to litter decomposition were studied. Results showed that long-term exposure to ZnO nanoparticles and visible light led to a significant decrease in litter decomposition rate (0.26 m−1 vs 0.45 m-1), and visible light would increase the inhibitory effect (0.24 m-1), which caused significant decrease in pH value of litter cultures, fungal sporulation rate, as well as most extracellular enzyme activities. The phototoxicity of ZnO nanoparticles also showed impacts on fungal community composition, especially on the genus of Varicosporium, whose abundance was significantly and positively related to decomposition rate. In conclusion, our study provides the evidence for negatively effects of ZnO NPs photocatalysis on ecological process of litter decomposition and highlights the contribution of visible light radiation to nanoparticles toxicity in freshwater ecosystems.

Enzyme-aided Cl 2 bleaching is widely considered as promising replacements for conventional Cl 2 bleaching in wood pulp and paper mills. However, the effects of using enzyme-aided bleaching on the formation of polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) in the non-wood pulp and paper mills are unclear. A field study was performed to investigate PCDD/F formation when enzyme-aided Cl 2 bleaching was used to replace conventional Cl 2 bleaching in non-wood pulp and paper mills. Unexpectedly, the PCDD/F toxic equivalents (TEQs) in solid samples were higher when using enzyme-aided bleaching (0.49–5.4 pg TEQ/g) than that using conventional Cl 2 bleaching (0.15–2.44 pg TEQ/g). Large amounts of octachlorodibenzo- p -dioxin were formed during the enzyme-aided bleaching process. This could have been because enzyme strongly promoted the release of organic molecules bound to lignin and thus accelerated the formation of octachlorodibenzo- p -dioxin through organic molecular precursors. Although enzyme-aided Cl 2 bleaching was previously considered to be efficient for reducing PCDD/F releases and to be the best available technologies and best environmental practices for wood pulp and paper mills, the results obtained in this study suggested the necessity and urgency to evaluate the suitability of enzyme-aided Cl 2 bleaching for non-wood pulp and paper mills that intensively practiced in developing countries.

Bromochloroacetic acid is classified as one of the typical disinfection byproducts (DBPs). In this work, supported palladium catalysts on different supports (CeO