Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg0) are currently levelling off. In the future, however, evasion from land ...surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season.
In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification.
Display omitted
•Presence and dangers of medieval mining sites are often forgotten and neglected.•Hg-concentrations are raised in conifer needles in a former German mining district.•Concentrations increase with needle age and are above those from national networks.•In the study area, Hg-concentrations are also elevated in certain mushroom species.•Consuming locally sourced mushrooms may result in a high total weekly Hg intake.
Unexplained cyanosis without any complex congenital heart disease needs further diagnostic work up. We present an adolescent child presenting with unexplained cyanosis who was found to have diffuse ...pulmonary arteriovenous malformations (PAVMs) due to abernethy malformation type 2, a variety of congenital extrahepatic portosystemic shunt (CEPS). This malformation was successfully closed by endovascular occlusion.
Display omitted
•95% of phosphorus from wastewater was concentrated into Fe-sludge at 25 mg/L FeCl3.•Phosphorus release and recovery from alkaline Fe-sludge fermentation was studied.•69.35% of ...phosphorus was released at pH 11 with 20.57 mg/L.•90% of the released phosphorus in the fermented liquid can be precipitated as MAP.
Phosphorus release and recovery from Fe-based chemically enhanced primary sedimentation (CEPS) sludge via alkaline fermentation was investigated. The coagulation results showed that 78% of organic matter and 95% of phosphorus were concentrated from sewage into sludge with the optimum dosages of 25 mg/L FeCl3. The batch fermentation results revealed that 69.35% of the phosphorus in the Fe-sludge can be released and the maximum phosphorus concentration was 20.57 mg/L at pH 11. In the recovery stage, 90% of the P released in the fermented sludge supernatant was precipitated at a 2:1 ratio of magnesium to phosphorus and pH 11. The result of X-ray diffraction indicated that magnesium ammonium phosphate (MAP) was the major component of the precipitated solids. Thus, the present study provides an alternative option for phosphorus release and recovery as MAP from CEPS sludge via alkaline fermentation.
Display omitted
•PACl and FeCl3 perform similarly for chemically enhanced primary sedimentation (CEPS).•Fe coagulant shows no inhibitory effect on organic hydrolysis of CEPS Fe-sludge.•PACl coagulant ...has an inhibitory effect on the organic hydrolysis of CEPS Al-sludge.•FeCl3 is more favored than PACl in CEPS use for organic and P recovery from the sludge.
FeCl3 and PACl as coagulants in chemically enhanced primary sedimentation (CEPS) were compared in terms of their efficiencies in removing pollutants from wastewater and their effects on the acidogenic fermentation of CEPS sludge for resource recovery. PACl was found to be more effective than FeCl3 for removing suspended solids by CEPS, with around 20% higher removal efficiency. However, the coagulated Al-sludge experienced more difficulty and had lower efficiency than Fe-sludge in organic hydrolysis and acidogenesis. The batch fermentation results showed that FeCl3 dosed at 10–30mg Fe/Lsewage had little influence on sludge hydrolysis and volatile fatty acid (VFA) production, whereas an obvious inhibitory effect was observed for PACl in organic hydrolysis of the sludge. The specific hydrolysis rate constant (Kh,P) for sludge fermentation decreased from 0.0321 for the sludge without PACl to 0.017 for the Al-sludge obtained at a dosage of 24mgAl/Lsewage. Compared to the Al-sludge, the Fe-sludge had a much higher VFA yield and significant PO4–P release during the sludge fermentation, which is attributed to the reduction of Fe(III) to Fe(II) under anaerobic conditions and the resulting disintegration of sludge flocs. By simple pH adjustment of the fermented Fe-sludge supernatant, up to 31% of the phosphorus in wastewater can be recovered in the form of vivianite as P fertilizers. VFAs produced in the supernatant are valuable organic carbon resources that can be recovered for beneficial uses.
Overweight and obesity among adolescents has become a common public health problem, and both obesity rates and the amount of pocket money among adolescents in China are rising. We investigated to ...what extent the increase in pocket money could lead to weight gain of junior high school students and how this association may vary by school environment in China. Researchers utilized 3 waves of data from the China Education Panel Survey, a national longitudinal study, to investigate the likelihood of overweight and obesity. The Generalized Estimation Equation was employed to analyze the data. Three Generalized Estimation Equation models were constructed to explore the relationship between pocket money and overweight and obesity in 2 distinct food environments surrounding schools. A total of 8903 individuals (4604 boys and 4299 girls) from the China Education Panel Survey were analyzed. After adjusting for confounding factors, it was found that girls who received 20 to 49 yuan and ≥ 50 yuan per week had a higher risk of overweight and obesity compared to those who received 0 to 9 yuan per week (OR = 1.34, 95% CI: 1.07–1.69, OR = 1.53, 95% CI: 1.22–1.92). However, no significant association was observed between pocket money and overweight and obesity when food around the school was not easily accessible. The prevalence of overweight among Chinese teenagers has steadily increased from Wave1 to Wave3. Moreover, junior high school girls who receive more pocket money are at a greater risk of developing obesity and overweight issues.
Geopolymer is an alternative binder to ordinary Portland cement (OPC) and expanded polystyrene (EPS) has been used as lightweight aggregates (LWA) to manufacture lightweight geopolymer composites ...(LWGC). Nevertheless, incorporating EPS beads in LWGC resulted in a significant decrease in mechanical properties as reported in a previous study. To achieve LWGC with a higher strength-to-weight ratio, a new commercially available coated expanded polystyrene (CEPS) with fibre reinforced epoxy was used as LWA for mixing LWGC in this study. Quasi-static and dynamic tests of the developed LWGC were conducted by using the universal test machine and Ø100-mm split Hopkinson pressure bar (SHPB) system, respectively. The physical properties of LWGC, such as density, workability and microstructure, were reported first, followed by the quasi-static mechanical properties including compressive and splitting tensile strength, modulus of elasticity and Poisson's ratio. Then the failure processes and failure modes observed in dynamic compressive and splitting tensile tests were reported and discussed. The strain rate effects on the dynamic properties, including the compressive and splitting tensile strengths, compressive critical strain and modulus of elasticity of LWGC with various CEPS contents, were revealed. The energy absorption capacities of the tested specimens were also examined. Furthermore, empirical formulae were proposed to predict the dynamic increase factors of both the compressive and splitting tensile strengths as well as energy absorption capacities of LWGC.
Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of ...organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl3-based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics.
Display omitted
•Fe-based CEPS sludge was fermented at different pHs for production of VFAs.•Highest VFAs yield occurred in CEPS sludge fermentation at stable pH 6.•Microbial community dynamics was reported for the CEPS sludge acidogenesis.•100 mg-COD/L of organic was recovered from wastewater via CEPS sludge fermentation.
Strategies for the efficient synthesis of peptide macrocycles have been a long‐standing goal. In this paper, we demonstrate the use of the peptide ligase termed omniligase‐1 as a versatile and ...broadly applicable enzymatic tool for peptide cyclization. Several head‐to‐tail (multi)cyclic peptides have been synthesized, including the cyclotide MCoTI‐II. Cyclization and oxidative folding of the cyclotide MCoTI‐II were efficiently performed in a one‐pot reaction on a 1‐gram scale. The native cyclotide was isolated and the correct disulfide bonding pattern was confirmed by NMR structure determination. Furthermore, compatibility of chemo‐enzymatic peptide synthesis (CEPS) using omniligase‐1 with methods such as chemical ligation of peptides onto scaffolds (CLIPS) was successfully demonstrated by synthesizing a kinase‐inhibitor derived tricyclic peptide. Our studies indicate that the minimal ring size for omniligase‐1 mediated cyclization is 11 amino acids, whereas the cyclization of peptides longer than 12 amino acids proceeds with remarkable efficiency. In addition, several macrocycles containing non‐peptidic backbones (e.g., polyethylene glycol), isopeptide bonds (amino acid side‐chain attachment) as well as d‐amino acids could be efficiently cyclized.
•The PTC achieved efficient removal of COD (79.2%) and PO43− (99%) from sewage.•A high VFAs yield was achieved by co-fermenting with Ti-loaded sludge food waste.•The bacteria essential for VFAs ...generation experience substantial enrichment.•Metabolic characteristics of microbes related to VFA production are revealed.•P and Ti are respectively recovered as struvite and TiO2 from fermented residue.
Recovery of resources from domestic sewage and food waste has always been an international-thorny problem. Titanium-based flocculation can achieve high-efficient destabilization, quick concentration and separation of organic matter from sewage to sludge. This study proposed co-fermentation of the titanium-flocculated sludge (Ti-loaded sludge) and food waste towards resource recovery by converting organic matter to value-added volatile fatty acids (VFAs) and inorganic matter to struvite and TiO2 nanoparticles. When Ti-loaded sludge and food waste were co-fermented at a mass ratio of 3:1, the VFAs yield reached 3725.2 mg-COD/L (VFAs/SCOD 91.0%), which was more than 4 times higher than the case of the sludge alone. The 48-day semicontinuous co-fermentation demonstrated stable long-term operation, yielding VFAs at 2529.0 mg-COD/L (VFAs/SCOD 89.8%) and achieving a high CODVFAs/NNH4 of 58.9. Food waste provided sufficient organic substrate, enriching plenty of acid-producing fermentation bacteria (such as Prevotella 7 about 21.0% and Bacteroides about 9.4%). Moreover, metagenomic sequencing analysis evidenced the significant increase of the relative gene abundance corresponding to enzymes in pathways, such as extracellular hydrolysis, substrates metabolism, and VFAs biosynthesis. After fermentation, the precious element P (≥ 99.0%) and extra-added element Ti (≥99.0%) retained in fermented residues, without releasing to VFAs supernatant, which facilitated the direct re-use of VFAs as resource. Through simple and commonly used calcination and acid leaching methodologies, 80.9% of element P and 82.1% of element Ti could be successfully recovered as struvite and TiO2 nanoparticles, respectively. This research provides a strategy for the co-utilization of domestic sludge and food waste, which can realize both reduction of sludge and recovery of resources.
Display omitted
PDF
