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22781. 题目: Soil labile organic carbon sequestration is tightly correlated with the abundance and diversity of arbuscular mycorrhizal fungi in semiarid maize field | |||||
22782. 题目: The influence of organic carbon on the toxicity of sediment-associated dinonylnaphthalene sulfonic acids to the benthic invertebrates Tubifex tubifex and Hyalella azteca Naphthalene sulfonic acids (NSAs) are used extensively in industrial applications as dispersants in dyes, rubbers, and pesticides, and as anti-corrosive agents in coatings, gels, and sealants. This study examined the toxicity of three NSA congeners, barium dinonylnaphthalene sulfonate (BaDNS), calcium dinonylnaphthalene sulfonate (CaDNS), and dinonylnaphthalene disulfonic acid (DNDS), to two benthic species, Tubifex tubifex and Hyalella azteca. Two substrates with different levels of organic carbon (sediment [2%] and sand [0%]) were used in toxicity tests. Juvenile production was the most sensitive endpoint for T. tubifex: the 28-d EC50s were <18.2, 22.2, and 64.0 μg/g dw in sand and 281.3, 361.6, and 218.9 μg/g dw in sediment for BaDNS, CaDNS, and DNDS, respectively. The 28-d LC50s for H. azteca were similar among compounds: 115.3, 82.1, and 49.0 μg/g dry weight (dw) in sand, and 627.3, 757.9, and >188.5 μg/g dw in sediment, for BaDNS, CaDNS, and DNDS, respectively. However, when LC50s were estimated based on concentrations of NSAs measured in overlying water (which can be an important route of exposure for H. azteca), BaDNS and CaDNS were 3–4 orders of magnitude more toxic than DNDS. The NSAs examined were >3-fold more toxic when present in substrates with no organic carbon (e.g., sand) for all H. azteca endpoints where LC/EC50s could be calculated and for sublethal endpoints for T. tubifex. The organic carbon content of the sediment appears to have acted as a sink and reduced NSA toxicity by decreasing bioavailability. Environmental sediment samples were collected from 12 river sites across southern Ontario. The maximum concentration of CaDNS observed in sediment collected from this region was 2.8 μg/g dw in sediment with 2% organic carbon; 100-fold lower than the lowest EC10 in the current study. | |||||
22783. 题目: Assessing the Reactive Surface Area of Soils and the Association of Soil Organic Carbon with Natural Oxide Nanoparticles Using Ferrihydrite as Proxy | |||||
22784. 题目: Effects of organic matter–goethite interactions on reactive transport of nalidixic acid: Column study and modeling The fractionation of natural organic matter (NOM) and its impact on the binding of quinolones to mineral surfaces and transport behavior under flow-through conditions have been scarcely investigated. In this study, the sorption and transport of a widely used quinolone antibiotic, Nalidixic acid (NA), were investigated in goethite-coated sand (GCS) columns over a wide concentration range (5–50 mg/L) of Leonardite humic acid (LHA), a representative NOM. Simultaneous injection of NA and LHA in GCS columns mutually alter transport of each other, i.e. NA mobility and LHA molecular fractionation. Preloading of GCS column with LHA dramatically facilitated the transport behavior of NA, where nonspecific interactions with LHA-covered goethite surfaces controlled NA mobility. Simulations using a two-site nonequilibrium model showed that a modified sorption rate constant was required to accurately describe the breakthrough curves of NA under these conditions. This altered rate constant suggests that nonspecific interactions of NA on bound LHA may take place as an additional binding mechanism affecting adsorption kinetics. NOM fractionation alters sorption mechanisms and kinetics of quinolone antibiotics, which in turn affect their fractionation. These results may have important implications for an accurate assessment of the fate of these types of antibiotics in aquatic environments. | |||||
22785. 题目: Effect of submerged combustion evaporation on Cd complexation potential of organic matter in municipal solid waste landfill leachate Despite the strong ability for complexation of heavy metals, a high amount of humic substances (HS) is always contained in membrane retentate from municipal solid waste landfill leachates treatment processes. Submerged Combustion Evaporation (SCE) can be used to effectively concentrate the membrane retentate. However, the impact of the SCE treatment on HS complexation capacity is still unclear. Since cadmium (Cd) plays a vital role in the pollution of soil and food, this study investigated the influence of the SCE treatment on the Cd complexation potential of leachate HS. Specific effects and complexation properties on Cd complexation of leachate HS before and after the SCE treatment were demonstrated using the Non-Ideal Competitive Adsorption model. The results showed that the Cd complexation capacity of carboxyl sites increased from 3.76 to 4.65 mol/kg-Total Organic Carbon (TOC) after the SCE treatment, which agreed with the stoichiometric number of proton binding sites. Moreover, characterization results indicated that SCE increased the affinity of HS for Cd by enhancing the overall aromaticity of HS (E2:E4 from 9.8 to 9.3), dominantly due to the humic acid contribution. By modeling the practical Cd remediation scenarios, the enhanced Cd complexation performance of HS after SCE treatment was observed even at low pH values (pH = 5) or insufficient TOC content (TOC = 50 mg/L). | |||||
22786. 题目: Total organic carbon concentrations in ecosystem solutions of a remote tropical montane forest respond to global environmental change The response of organic C concentrations in ecosystem solutions to environmental change changes the release of dissolved organic matter from forests to surface and groundwaters. We determined the total organic C (TOC) concentrations (filtered <1‐7 µm) and the ratios of TOC/dissolved organic N (DON) concentrations, electrical conductivity (EC), and pH in all major ecosystem solutions of a tropical montane forest from 1998 to 2013. The forest was located on the rim of the Amazon basin in Ecuador and experienced increasing numbers of days with >25°C, decreasing soil moisture, and rising N deposition from the atmosphere during the study period. In rainfall, throughfall, mineral soil solutions (at the 0.15‐ and 0.30‐m depths), and streamflow, TOC concentrations and fluxes decreased significantly from 1998 to 2013, while they increased in stemflow. TOC/DON ratios decreased significantly in rainfall, throughfall, soil solution at the 0.15‐m depth, and streamflow. Based on Δ14C values, the TOC in rainfall and mineral soil solutions was 1 yr old and that of litter leachate 10 yr old. The pH in litter leachate decreased with time, that in mineral soil solutions increased, while those in the other ecosystem solutions did not change. Thus, reduced TOC solubility because of lower pH values cannot explain the negative trends of TOC concentrations in most ecosystem solutions. The increasing TOC concentrations and EC in stemflow pointed at an increased leaching of TOC and other ions from the bark. Our results suggest an accelerated degradation of dissolved organic matter (DOM), particularly of young DOM, associated with the production of N‐rich compounds simultaneously to changing climatic conditions and increasing N availability. Thus, environmental change increased the CO2 release to the atmosphere but reduced DOM export to surface and groundwater. | |||||
22787. 题目: Negative effects of oxytetracycline and copper on nitrogen metabolism in an aerobic fermentation system: Characteristics and mechanisms Aerobic fermentation is a sustainable option for livestock waste treatment, but little is known about the microbial mechanism that allows oxytetracycline (OTC) and copper (Cu) to affect nitrogen metabolism during aerobic fermentation. In this study, contamination with OTC and Cu alone or in combination reduced the total nitrogen (TN) content of the fermentation products. Metagenomic analysis demonstrated that the contribution of microorganisms to nitrogen metabolism changed significantly in different stages of fermentation. OTC and Cu affected the formation and utilization pattern of NO2−-N by microorganisms, which were mainly responsible for the reduced N2O emissions. In the presence of OTC and/or Cu, Myxococcus_stipitatus, Myxococcus_xanthus, and Gimesia_maris were evidently enriched at the end of fermentation, and their increased roles in the dissimilatory reduction of nitrite to ammonium were confirmed by network analysis. Ardenticatena_maritima was the main contributor to denitrification (NO3−-N to NO). Furthermore, organic matter (OM) was the most important factor responsible for driving the variation in nitrogen-transforming microorganisms and controlling denitrification. OTC affected the formation of OM, which can directly affect TN (λ = –0.37, p < 0.001), and the adverse impact of Cu on nirK- and nifH-dominant microorganisms was validated (p < 0.05). | |||||
22788. 题目: Nano-zerovalent manganese/biochar composite for the adsorptive and oxidative removal of Congo-red dye from aqueous solutions Congo-red (CR), a precursor of textile products and a contaminant of great concern, has contaminated aquatic environments. Here, we explored the synthesis of mesoporous nano-zerovalent manganese (nZVMn) and Phoenix dactylifera leaves biochar (PBC) composite for the removal of CR from water. The nZVMn/PBC adsorbed 117.647 mg/g of CR versus 25.316 mg/g by PBC at [CR]0 = 20 mg/L and [PBC]0 = [nZVMn/PBC]0 = 500 mg/L. Variation of [nZVMn/PBC]0, [CR]0 and pH influenced the adsorption of CR. Freundlich adsorption isotherm and pseudo-first-order kinetic models best fitted CR adsorption. The H2O2 coupling with nZVMn/PBC promoted removal of CR possibly due to the formation of hydroxyl radical (●OH) and caused 95 % removal of CR versus 77 % by nZVMn/PBC alone. The ●OH scavengers inhibited the removal of CR. The nZVMn/PBC showed a good reusability and efficient removal of CR up to the seventh cycle of treatment. Results reveal that nZVMn improved performance, thermal stability and reusability of biochar. Degradation products from ●OH-mediated degradation of CR were studied by ultraperformance liquid chromatography with mass spectrometric detector to establish degradation pathways. The ion-chromatographic analysis showed the formation of non-toxic inorganic acetate product, which suggests high potential of the newly fabricated adsorbent in the removal of CR. | |||||
22789. 题目: Life Cycle Assessment of Biochar Modified Bioasphalt Derived from Biomass | |||||
22790. 题目: Biochar amendment increases bacterial diversity and vegetation cover in trace element-polluted soils: A long-term field experiment Application of biochar has been widely suggested as a remediation tool for trace element-polluted soils, but the impact of biochar on microbial communities and on native plants remain largely unknown. To overcome this knowledge gap, biochar produced from rice husk and olive pit were applied at a rate of 8 t ha−1 into a soil with two contrasting levels of trace elements (high and moderate) to study their effects on soil microbial community composition, vegetation cover and soil properties after 1, 6, 12 and 20 months under field conditions. Differences in bacterial community composition were studied using the Illumina Miseq technology of the 16S rRNA gene. Although variations in soil properties and ecological function were seasonal and soil-type dependent, biochar application enhanced soil properties and vegetation cover in the moderately polluted soil (MPS), and increased microbial diversity as well as vegetation cover in the highly polluted soil (HPS). Enzymatic activities and soil respiration rates were not modified with the application of biochar, but increased total carbon content of soils. The application of biochar from crop residues to trace-element contaminated soils provided environmental benefits, including plant diversity and growth, as well as the increase of bacterial diversity and carbon sequestration. | |||||
22791. 题目: Biochar aging increased microbial carbon use efficiency but decreased biomass turnover time Biochar amendment causes immediate increases in soil organic carbon (SOC), but long-term effects are unclear. Biochar properties change with time (biochar aging) potentially affecting how efficiently SOC remains in soil after decomposition, indicated by microbial carbon use efficiency (CUE, the ratio of microbial growth over carbon uptake). Effects of fresh and aged biochar amendments on microbial CUE and biomass turnover time (BTT) were determined using the H218O-DNA incorporation method. Biochar aging increased CUE (control vs. fresh vs. aged of 0.6 vs. 0.6 vs. 0.7) but decreased BTT (51 vs. 37 vs. 27 days) due to changes in soil pH. Moreover, a greater CUE but shorter BTT was found in the sandy-textured Tenosol compared to the clayey Dermosol, possibly due to protection by clay minerals. Biochar aging and associated increase in soil pH may promote soil biogenic carbon sequestration through increasing microbial CUE or decreasing BTT. | |||||
22792. 题目: Permafrost existence is closely associated with soil organic matter preservation: Evidence from relationships among environmental factors and soil carbon in a permafrost boundary area Permafrost regions store a large amount of soil organic carbon (SOC). Although permafrost degradation with climate warming can stimulate soil organic matter (SOM) decomposition, it remains unknown that whether the permafrost existence benefits SOM preservation. Here, a boundary area of permafrost and non-permafrost zone was selected to test the hypothesis that SOM underlain by permafrost has been better preserved than the area without permafrost under similar climatic conditions. The interactions among topography, vegetation cover, permafrost, soil variables and SOC distribution were examined. The results showed the sites beneath wet meadow land covers, which are usually underlain by permafrost, have higher SOC stocks than those of alpine meadows without permafrost. Based on mixed effects models, both soil water content and bulk density explained higher SOC content variances in the sites without permafrost than the sites underlain by permafrost. The north-facing non-permafrost sites have significantly higher SOC contents than those in south-facing non-permafrost sites. Vegetation cover, aspect, and permafrost have mixing effects on SOC contents both in permafrost and non-permafrost sites. Soil particle size and the rock fragment content are good predictors for prediction of SOC contents, while the best predictor was depending on the presence of permafrost. These results suggested that under similar climatic conditions, permafrost existence favors the preservation of SOM, this should be taken into consideration in the future carbon emission from permafrost regions since permafrost degradation can lag behind climate warming in many areas. | |||||
22793. 题目: Geochemical characterization of sediments from the archaeological site Vinča – Belo Brdo, Serbia In this study, a multidisciplinary approach was used for a detailed characterization of sediments from the archaeological site Vinča – Belo Brdo, Serbia, one of the most important Neolithic settlements in Europe. This research aimed to determine the paleoenvironmental conditions during Pleistocene and Early Holocene sedimentation prior to Early Neolithic settlement (~5800 cal BC) and provide novel insight into the interaction between humans and the environment during the Middle and Late Neolithic (5300–4550 cal BC). For the first time, organic geochemical characterization, combined with organic petrography, grain size, mineralogy, and inorganic analysis were done on sediment samples from geological and archaeological sections of the Vinča – Belo Brdo site. In the archaeological section, the layer with remains of the burned house and the overlaying leveling layer were particularly interesting. The samples from the oldest geological layers were characterized by the relatively high content of carbonates, the largest amount of soluble organic matter (OM), predominance of liptinite macerals, along with the prevalence of short and mid-chain n-alkanes indicating a marsh-lake depositional environment. The sedimentation of overlaying geological layers continued in an oxbow lake, followed by a shallow depositional environment with stronger input of vascular plants. This was indicated by an increase of the terrigenous component, a high amount of huminite maceral, especially textinite, the predominance of odd long-chain n-alkanes, as well as the presence of diterpanes, pimarane, and 16α(H)-phyllocladane. Quartz was the most abundant mineral in paleosol, while the OM had a mixed origin with a major input of microorganism in the precursor biomass. Estimated average paleosol temperature around 12–16 °C and mean annual precipitation of 938 mm/yr were favorable for ancient civilization settlement. In archaeological samples, the OM was predominantly formed by microorganisms, with a certain contribution of terrestrial plants. Their occurrence was substantiated by the presence of telohuminite, detrohuminite, resinite, and sporinite. The prevalence of n-alkane C18, along with the occurrence of inertinite macerals, semifusinite and fusinite, in the layer with the burned house remains confirmed the incomplete combustion of woody biomass at temperatures <500 °C. Organic and inorganic geochemical parameters for the leveling layer covering the destroyed buildings showed analogous composition as the lowest geological layers. This proved that Vinča inhabitants excavated material for leveling at a site in their vicinity, and used it for covering the burnt debris, clearing the areas for a new settlement. In this context, the decades long archaeological dilemma of the origin of the leveling material was resolved. | |||||
22794. 题目: Modified montmorillonite and illite adjusted the preference of biotic and abiotic pathways of humus formation during chicken manure composting The study aimed to identify the preference of pathways of humus formation. Five lab-scale composting experiments were established: the control (CK), montmorillonite addition (M), illite addition (I), thermal treatment montmorillonite addition (M-) and thermal treatment illite addition (I-). Results showed humus content was increased by 11.5%, 39.3%, 37.2%, 30.9% and 27.6% during CK, M-, M, I- and I composting. Meanwhile, Redundancy analysis indicated the bands of bacteria community related to humic acid (HA) were more abundant in the M- and I- treatments. Furthermore, structural equation model and variance partitioning analysis demonstrated that M- and I- treatments promoted precursors to synthesize HA by coordinated regulation of biotic pathway and abiotic pathway, the increase of HA in the M and I treatments mainly through the abiotic pathway. In summary, an effective method was proposed to improve humus production by adjusting the preference of biotic and abiotic pathways of humus formation. | |||||
22795. 题目: Exploring the optimized strategy in the nitritation-anammox biofilm process for treating low ammonium wastewater The main challenge for achieving the simultaneous nitritation, anammox and denitrification (SNAD) process is to optimize the concentrations of nitrite and dissolved oxygen (DO). This study explored the performance of SNAD biofilm reactor under three operational strategies. At Stage 1, 2 and 3, the average concentrations of DO were 0.7, 2.7 and 5.2 mg/L, respectively. The peak concentrations of NO2--N in the sequencing batch reactor (SBR) cycle were 5.3, 6.0 and 2.7 mg/L, respectively. The average removal rates of total inorganic nitrogen (TIN) were 0.30, 0.42 and 0.22 kg N/m3/d, respectively. Protein (PN) was the dominant extracellular polymeric substance (EPS) content on the SNAD biofilm. The PN concentration remained stable while the polysaccharide (PS) concentration changed rapidly under different operational strategies. High-throughput sequencing analysis indicated that high DO and long aeration period condition could lead to a slight decrease in the abundances of denitrifying bacteria and anammox bacteria. | |||||
22796. 题目: Monitoring dissolved organic matter in wastewater and drinking water treatments using spectroscopic analysis and ultra-high resolution mass spectrometry Dissolved organic matter (DOM) plays a critical role in determining the quality of wastewater and the safety of drinking water. This is the first review to compare two types of popular DOM monitoring techniques, including absorption spectroscopy and fluorescence excitation-emission matrices (EEMs) coupled with parallel factor analysis (PARAFAC) vs. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), for the applications in wastewater and drinking water treatments. The optical techniques provide a series of indices for tracking the quantity and quality of chromophoric and fluorescent DOM, while FT-ICR-MS is capable of identifying thousands of DOM compounds in wastewater and drinking water at the molecule level. Both types of monitoring techniques are increasingly used in studying DOM in wastewater and drinking water treatments. They provide valuable insights into the variability of DOM composition in wastewater and drinking water. The complexity and diversity of DOM highlight the challenges for effective water treatments. Different effects of various treatment processes on DOM are also assessed, which indicates that the information on DOM composition and its removal is key to optimize the treatment processes. Considering notable progress in advanced treatment processes and novel materials for removing DOM, it is important to continuously utilize these powerful monitoring tools for assessing the responses of different DOM constituents to a series of treatment processes, which can achieve an effective removal of DOM and the quality of treated water. | |||||
22797. 题目: Production, properties, and catalytic applications of sludge derived biochar for environmental remediation Environment-friendly and cost-effective disposal and reutilization of sludge wastes are essential in wastewater treatment processes (WWTPs). Converting activated sludge into biochar via thermochemical treatment is a promising technology for waste management in WWTPs. This review summarizes the compositions of sludge, the dewatering methods, and the thermochemical methods which influence the structures, chemistry, and catalytic performances of the derived biochar. Moreover, the physiochemical characteristics and chemical stability of sludge biochar are discussed. Catalytic applications of biochar are highlighted, including the reaction mechanisms and feasibility for catalytic removal of organic contaminants. High-temperature carbonized sludge biochar exhibits excellent performance for persulfate activation in advanced oxidation processes due to the graphitic carbon structure, newly-created active sites, and fine-tuned metal species. Therefore, the sludge biochar can be produced via cost-effective and eco-friendly approaches to immobilize harmful components from sludge and remediate organic pollution in wastewater, offering a sustainable route toward sludge reutilization into value-added products for water purification. | |||||
22798. 题目: Effect of prescribed fires on the export of dissolved organic matter, precursors of disinfection by-products, and water treatability In this study, we report for the first time the effect of prescribed fires on the export of dissolved organic matter (DOM), and precursors of disinfectant by-products (DBPs) from periodically (every 2-3 years) and seasonally (i.e., dormant and growing) burned forest fuel materials (i.e., live vegetation, woody debris, and detritus [litter and duff]), and treatability of its rainwater leachate. Periodically applied (every 2-3 years for 40 years) prescribed fires decreased total fuel load (62±10 %), primarily detrital mass (75±2 %). However, functional groups (i.e., phenolic compounds, proteins, carbohydrates, aromatic [1-ring], polycyclic aromatic hydrocarbons [PAHs], and lipids) attached to DOM of ground solid materials did not change significantly. Outside rainwater leaching (from forest fuel materials) experiments showed that the leaching capacity of dissolved organic carbon (DOC) from burned litter samples decreased by 40±20 % regardless of the burning season compared to unburned litter samples. The leaching of total dissolved nitrogen (TDN), dissolved organic nitrogen (DON), ammonium (NH4+), and reactive phosphorus (PO43−) from burned materials decreased between 40 and 70% when compared to unburned materials. Also, DOM composition was affected by prescribed fire, which partially consumed humic-like substances based on fluorescence analyses. Thus, periodically applied prescribed fires also resulted in a reduction of trihalomethane (THM) (42±23 %) and haloacetic acid (HAA) (42±20 %) formation potentials (FPs), while DOC normalized reactivity of THM and HAA FPs did not change significantly. Additionally, the leaching of N-nitrosodimethylamine (NDMA) precursors, bromide ion (Br−), and selected elements (K, Ca, Mg, Mn, Fe, S, Na, B, and Al) were not significantly affected by prescribed fires. Finally, coagulant (i.e., alum and ferric) dose requirements and coagulation efficiencies were similar (i.e., removal of DOC, precursors of THMs and HAAs were 52-56 %, 69-70 %, 78-79 %, respectively) in unburned and pre-burned leachate samples. | |||||
22799. 题目: Algal biomarkers as a proxy for pCO2: Constraints from late Quaternary sapropels in the eastern Mediterranean Records of carbon dioxide concentrations (partial pressure expressed as pCO2) over Earth's history provide trends that are critical to understand our changing world. To better constrain pCO2 estimations, here we test organic pCO2 proxies against the direct measurements of pCO2 recorded in ice cores. Based on the concept of stable carbon isotopic fractionation due to photosynthetic CO2 fixation (Ɛp), we use the stable carbon isotopic composition (δ13C) of the recently proposed biomarker phytol (from all photoautotrophs), as well as the conventionally used alkenone biomarkers (from specific species) for comparison, to reconstruct pCO2 over several Quaternary sapropel formation periods (S1, S3, S4, and S5) in the eastern Mediterranean Sea. The reconstructed pCO2 values are within error of the ice core values but consistently exceed the ice core values by ca. 100 µatm. This offset corresponds with atmospheric disequilibrium of present day CO2[aq] concentrations in the Mediterranean Sea from global pCO2, equivalent to ca. 100 µatm, although pCO2 estimates derived from individual horizons within each sapropel do not covary with the ice core values. This may possibly be due to greater variability in local CO2[aq] concentration changes in the Mediterranean, as compared with the global average pCO2, or possibly due to biases in the proxy, such as variable growth rate or carbon-concentrating mechanisms. Thus, the offset is likely a combination of physiological or environmental factors. Nevertheless, our results demonstrate that alkenone- and phytol-based pCO2 proxies yield statistically similar estimations (P-value = 0.02, Pearson's r-value = 0.56), and yield reasonable absolute estimations although with relatively large uncertainties (± 100 µatm). | |||||
22800. 题目: Microbial biomarkers reveal a hydrothermally active landscape at Olduvai Gorge at the dawn of the Acheulean, 1.7 Ma | |||||
