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17561. 题目: Delineating Source Contributions to Stream Dissolved Organic Matter Composition Under Baseflow Conditions in Forested Headwater Catchments
文章编号: N21071807
期刊: Journal of Geophysical Research: Biogeosciences
作者: M. P. Silva, K. Blaurock, B. Beudert, J. H. Fleckenstein, L. Hopp, S. Peiffer, T. Reemtsma, O. J. Lechtenfeld
更新时间: 2021-07-18
摘要: Dissolved organic matter (DOM) composition in streams reflects the dynamic interplay between DOM sources, mobilization mechanisms, and biogeochemical transformations within soils and receiving water bodies. The information regarding DOM sources being mobilized during baseflow can improve our ability to predict hydrological and biogeochemical responses to environmental changes, with implications for catchment management strategies. The objective of this study was to characterize the spatial changes in DOM composition along a headwater stream during baseflow and to link the findings in-stream with possible DOM sources in the catchment. DOM was monitored over 1.5 years at three sites in the Große Ohe catchment (19.2 km2), within the Bavarian Forest National Park, using UV-Vis absorption indicators of aromaticity (SUVA) and molecular weight (E2:E3) from high-frequency probe measurements. Additionally, discrete samples were collected and analyzed by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). At baseflow conditions, DOC concentrations – a proxy of DOM amount – ranged from 1.5 to 4.7 mg L-1 and were similar along the slope gradient. However, DOM quality exhibited clear spatial patterns, with overall high aromatic and low molecular weight DOM in the lower part of the catchment. Moreover, molecular data revealed that oxygen-rich, aromatic compounds increased their abundance at high DOC concentrations in both upper and lower part of the catchment, with also additional input of oxygen-depleted, aromatic compounds identified in the lower part. In contrast, nitrogen-rich, aliphatic compounds were negatively correlated with DOC concentration, indicating a higher contribution of deep groundwater flows.

17562. 题目: Identification and spatial mapping of tracers of PM10 emission sources using a high spatial resolution distributed network in an urban setting
文章编号: N21071806
期刊: Atmospheric Research
作者: Lorenzo Massimi, Joost Wesseling, Sjoerd van Ratingen, Iqra Javed, Maria Agostina Frezzini, Maria Luisa Astolfi, Silvia Canepari, Roel Vermeulen
更新时间: 2021-07-18
摘要: We employed an experimental approach for high spatial resolution sampling and analysis of PM10, allowing identification and spatial mapping of tracers of PM10 emission sources. Very-low-volume samplers were used at 17 sites in Amersfoort and at one regulatory reference site in Utrecht, The Netherlands, in a 5-month monitoring period (from September 2018 to February 2019), to assess the monthly spatial distribution of PM10 mass and PM10 chemical compounds. By performing principal component analysis on the obtained spatially-resolved data, selective and reliable source tracers were identified for soil dust (Ca+, Cl−, insoluble Al, Ce, Li, U and V), brake dust (insoluble Fe, Mn, Mo, Nb, Sb, Sn, W and Zr, water-soluble Fe, Mn, Mo and Sb), industrial and/or agricultural emissions (NH4+, water-soluble As, Co, Fe, Mn, Mo, Pb, Sb, Se, Sn and Ti), secondary organic and inorganic aerosols (water-soluble organic carbon, NO3− and SO42−), biomass domestic heating (water-soluble organic carbon, levoglucosan, water-soluble Cs, Li, Rb and Tl) and New Year's Eve fireworks (K+, Mg2+, Na+, water-soluble Al, Ba, Bi, Cr, Cu and Sr). The autumn and winter spatial mapping of the identified source tracers allowed us to effectively assess and localize the impact of the different PM10 sources and to evaluate the diffusion of the PM10 particles. This approach proved to be very effective to trace low-intensity PM10 sources and to map their seasonal spatial distribution. The obtained spatially-resolved chemical data can be used in further studies to evaluate spatial relationships between the concentration of PM10 air pollutants and adverse outcomes for human health. This approach promises to be a powerful tool for obtaining seasonal and spatially-resolved information about PM composition and sources in several study areas that can be integrated with data from existing networks, having high impact on the air quality management.

17563. 题目: Simultaneous recovery of valuable metal ions and tailings toxicity reduction using a mixed culture bioleaching process
文章编号: N21071805
期刊: Journal of Cleaner Production
作者: Xiaojian Liao, Maoyou Ye, Shoupeng Li, Jialin Liang, Siyu Zhou, Xiaodi Fang, Qiaowei Gan, Shuiyu Sun
更新时间: 2021-07-18
摘要: Lead–zinc sulfide mine tailings without appropriate disposal would cause resource waste and heavy metal pollution in the environment. This study aims to design a novel mixed culture A with higher leaching performance to improve the leaching efficiency of tailings, because mixed culture B consisting of ferrous oxidizer Leptospirillum ferriphilum (L. ferriphilum) and sulfur oxidizer Acidithiobacillus thiooxidans still has a long leaching period. The results showed that mixed culture A containing ferrous/sulfur oxidizers Acidithiobacillus ferrooxidans and Sulfobacillus thermosulfidooxidans shortened the bioleaching cycle by 30% to achieve the same zinc yield (94.0%) as mixed culture B. Thus, ferrous/sulfur oxidizers offer a competitive advantage over ferrous oxidizer and sulfur oxidizer, respectively, during bacterial combination to leach tailings. The better performance of mixed culture A was verified by its higher content of extracellular polymeric substances and living cells density (30.2 × 107 cells mL−1). Furthermore, data from microbial community succession also revealed that two bacteria could together produce acid in the mixed culture A system to substantially facilitate zinc leaching, while only L. ferriphilum played a role in mixed culture B system. Interestingly, results from toxicity evaluation of bioleached residues indicated that mixed culture A dramatically reduced the potential ecological risk index of tailings from 161.80 to 7.50, transforming tailings from hazardous waste into non-hazardous one. In brief, this study proposes a novel perspective for bacterial combinations to improve tailings bioleaching and reveals that bioleaching can reduce the eco-environmental risk of tailings.

17564. 题目: Applying CCB to predict management change affected long‐term SOM turnover of the Extended Static Fertilization Experiment in Bad Lauchstädt
文章编号: N21071804
期刊: European Journal of Soil Science
作者: U. Franko, J. Diel, J. Ruehlmann
更新时间: 2021-07-18
摘要: Long-term field experiments (LTEs) are an invaluable source to improve understanding of soil organic matter (SOM) turnover, as some of the involved processes are proceeding over centuries. Prediction of such slow carbon fluxes depends especially on the initialisation of slow reacting model pools and requires monitoring for a very long time for evaluation.

17565. 题目: EVALUATION OF A LEACH BED REACTOR FOR THE ANAEROBIC DIGESTION OF DRYLOT COLLECTED CATTLE MANURE
文章编号: N21071803
期刊: Journal of Environmental Chemical Engineering
作者: Asma Hanif, Lucas Loetscher, Sybil Sharvelle
更新时间: 2021-07-18
摘要: Conventional anaerobic digestion (AD) technologies are not appropriate for processing drylot collected manure without excessive water addition. An alternative AD approach, the leach bed reactor (LBR), may facilitate the digestion of drylot manures with minimal water use but leach bed reactors (LBRs) are known to experience hydraulic failures with manure wastes. The addition of a top sand layer to LBRs is investigated to facilitate the processing of drylot cattle manure containing up to 90% total solids (TS) without hydraulic failure. Here, LBRs were operated to overcome clogging issues and assess the extent of hydrolysis of organic matter in the manure. The system was operated as a batch process with a digestion time of 42 days. The LBRs showed a mean total chemical oxygen demand (COD) reduction of 51.6% and a total volatile solids reduction of 44.7% in manure. Biochemical methane potential tests on leachate indicated a mean methane yield of 0.13L CH4/g COD leached. The appropriate operational time for the system was found to be 14 days.

17566. 题目: Adsorption and mechanistic study for humic acid removal by magnetic biochar derived from forestry wastes functionalized with Mg/Al-LDH
文章编号: N21071802
期刊: Separation and Purification Technology
作者: Jian Zhang, Wenjing Lu, Siyan Zhan, Junming Qiu, Ximo Wang, Zhengde Wu, Hui Li, Zumin Qiu, Hailong Peng
更新时间: 2021-07-18
摘要: A novel adsorbent of Mg/Al-LDH functionalized magnetic biochar from waste poplar sawdust (CoFe2O4@PBC-LDH) and bamboo powder (CoFe2O4@BBC-LDH) was developed, and the removal performance of HA from aqueous solution was investigated. The Mg/Al-LDH was effectively functionalized on the CoFe2O4@BC surface via co-precipitation method. The CoFe2O4@BC-LDH exhibited a brush structure with larger surface area and higher adsorption capability. The adsorption mechanism was mainly the ions exchange and electrostatic interactions between CoFe2O4@BC-LDH and HA. The adsorption of HA was well fitted to the Freundlich model with endothermic nature and spontaneous process. CoFe2O4@BC-LDH showed remarkable adsorption capacity for HA, and the maximum adsorption capacity for CoFe2O4@PBC-LDH and CoFe2O4@BBC-LDH were 240.58 and 337.83 mg·g−1 at 25°C, respectively. The adsorption process was conformed to the pseudo-second-order model and dominated by the chemisorption. Meanwhile, the coexisting ions could conducive to the adsorption capacity of CoFe2O4@BC-LDH for HA. Most importantly, CoFe2O4@BC-LDH exhibited an excellent adsorption capacity in real water samples with long-term stability, and which can be easily recycled from water under an external magnet. Therefore, this work provides new insights into the fabrication of low-cost biochar from forestry wastes and that can be used to develop a high-performance adsorbent for removal of contaminants.

17567. 题目: Phytostabilization of a contaminated military site using miscanthus and soil amendments
文章编号: N21071801
期刊: Journal of Environmental Quality
作者: Zafer Alasmary, Ganga Hettiarachchi, Kraig L. Roozeboom, Lawrence C. Davis, Larry Erickson, Valentina Pidlisnyuk, Tetyana Stefanovska, Josef Trögl
更新时间: 2021-07-18
摘要: Military activities can contaminate productive land with potentially toxic substances. The most common trace metal contaminant on military bases is lead (Pb). A field experiment was begun in 2016 at Fort Riley, KS, in an area with total soil Pb concentrations ranging from 900 to 1,500 mg kg–1 and near-neutral pH. The main objectives were to test the potential of Miscanthus sp. for phytostabilization of the site and to evaluate the effects of soil amendments on Miscanthus growth, soil-plant Pb transfer, bioaccessibility of soil Pb, and soil health. The experimental design was a randomized complete block, with five treatments and four replications. Treatments were: (i) existing vegetation, (ii) Miscanthus planted in untilled soil, no amendments, (iii) Miscanthus planted in tilled soil, (iv) Miscanthus planted in tilled soil amended with inorganic P (triple superphosphate applied at 5:3 Pb:P), and (v) Miscanthus planted in tilled soil amended with organic P (class B biosolids applied at 45 Mg ha–1). Tilling and soil amendments increased dry matter yields only in the establishment year. Total Pb uptake, plant tissue Pb concentration, and soil Pb bioaccessibility were significantly less in the Miscanthus plots amended with biosolids than the Miscanthus plots with no added P across all three years. Enzyme activities, organic carbon, and microbial biomass were also greater in biosolids-treated plots. Results show that planting-time addition of soil amendments to Pb-contaminated soil supported Miscanthus establishment, stabilized and reduced bioaccessibility of soil Pb, reduced concentration and uptake of Pb by Miscanthus, and enhanced soil health parameters.

17568. 题目: Divergent controls of soil organic carbon between observations and process-based models
文章编号: N21071712
期刊: Biogeochemistry
作者: Katerina Georgiou, Avni Malhotra, William R. Wieder, Jacqueline H. Ennis, Melannie D. Hartman, Benjamin N. Sulman, Asmeret Asefaw Berhe, A. Stuart Grandy, Emily Kyker-Snowman, Kate Lajtha, Jessica A. M. Moore, Derek Pierson, Robert B. Jackson
更新时间: 2021-07-17
摘要: The storage and cycling of soil organic carbon (SOC) are governed by multiple co-varying factors, including climate, plant productivity, edaphic properties, and disturbance history. Yet, it remains unclear which of these factors are the dominant predictors of observed SOC stocks, globally and within biomes, and how the role of these predictors varies between observations and process-based models. Here we use global observations and an ensemble of soil biogeochemical models to quantify the emergent importance of key state factors – namely, mean annual temperature, net primary productivity, and soil mineralogy – in explaining biome- to global-scale variation in SOC stocks. We use a machine-learning approach to disentangle the role of covariates and elucidate individual relationships with SOC, without imposing expected relationships a priori . While we observe qualitatively similar relationships between SOC and covariates in observations and models, the magnitude and degree of non-linearity vary substantially among the models and observations. Models appear to overemphasize the importance of temperature and primary productivity (especially in forests and herbaceous biomes, respectively), while observations suggest a greater relative importance of soil minerals. This mismatch is also evident globally. However, we observe agreement between observations and model outputs in select individual biomes – namely, temperate deciduous forests and grasslands, which both show stronger relationships of SOC stocks with temperature and productivity, respectively. This approach highlights biomes with the largest uncertainty and mismatch with observations for targeted model improvements. Understanding the role of dominant SOC controls, and the discrepancies between models and observations, globally and across biomes, is essential for improving and validating process representations in soil and ecosystem models for projections under novel future conditions.

17569. 题目: Changes in soil chemical composition caused by self‐heating of coal‐waste dump
文章编号: N21071711
期刊: Land Degradation & Development
作者: Anna Abramowicz, Oimahmad Rahmonov, Monika J. Fabiańska, Ádám Nádudvari, Ryszard Chybiorz, Michał Michalak
更新时间: 2021-07-17
摘要: The paper presents soil features and chemical composition in a self-heating coal-waste dump. The investigations were carried out in the Upper Silesian Coal Basin. A fire zone in which the soil temperature exceeded 50°C was selected. Soil analyses were carried out for three grain sizes – d > 1 mm, 0.063 mm < d ≤ 1 mm, and d ≤ 0.063 mm – enabling identification of the diversity of the chemical composition in soil fractions. The highest concentration of heavy metals is represented by Mn (212-6972 mg/kg), Zn (127-3283 mg/kg), Pb (33.6-1344.7 mg/kg), Cu (38.9-101.4 mg/kg), and major elements by Fe (14300-117400 mg/kg), Ca (900-63600 mg/kg). Soil chemistry showed variations within individual studied sites. The soil reaction ranges from acidic (4.3 in KCl and 5.26 in H2O) to moderate alkaline (7.96 in H2O, 7.31 in KCl), whereas TOC ranges from 1.21-14.60% and TN from 0.023-0.291%. The distribution of n-alkanes clearly showed a low degree of transformation of organic matter and characteristic high values of Pr/Ph ratio for humic coals and coal waste in the region. Grains with diameters greater than 1 mm exhibited completely different features than those of fractions smaller than or equal to 1 mm. High organic carbon content (14.60) was detected in the samples along with PAHs. The influence of fire on the chemical composition of all samples was identified using geochemical indicators. PCA analysis showed that the values of the variables were more closely correlated in finer grains than in the coarsest fraction.

17570. 题目: Toxicity reduction of reverse osmosis concentrates from petrochemical wastewater by electrocoagulation and Fered-Fenton treatments
文章编号: N21071710
期刊: Chemosphere
作者: Chenhao Gong, Xiaojing Ren, Junxing Han, Yue Wu, Yaling Gou, Zhongguo Zhang, Peiran He
更新时间: 2021-07-17
摘要: In this work, both Electrocoagulation (EC) and Fered-Fenton (FF) technologies were used to treat reverse osmosis concentrates (ROC) from petrochemical production. The toxicity reduction capacity and mechanism were comparatively assessed during these two treatments. The results showed that FF exhibited higher capacity to reduce toxicity than EC in the 30 min treatment, which could be attributed to the removal of organic pollutants and heavy metals. The results showed that the ROC contained organics with molecular weight of 1200 g mol−1 and 220 g mol−1, which mainly consisted of the soluble microbial by-product-like and humic acid-like substances. The removal of these organics directly led to the noticeable toxicity reduction. Alkanes, haloalkanes, ketones, PAHs, and other four organic pollutants were the dominant species in the ROC, and the removal of small molecular weight organic pollutants played an essential role in reducing toxicity. FF exhibited stronger capacity to remove PAHs, BTEXS and haloalkanes, and the removal efficiencies for the PAHs were in the following order: 5-ring > 4-ring > 3-ring > 2-ring. The promotion of heavy metals removal appeared to be favorable for decreasing toxicity in ROC. This study illustrated the mechanism of the toxicity reduction and the characteristics of pollutants removal during FF and EC treatments, and provided valuable guidance for petrochemical manufacturing to the toxicity reduction and operation of wastewater treatment facilities.

17571. 题目: Surface Properties of Nanoparticles Dictate Their Toxicity by Regulating Adsorption of Humic Acid Molecules
文章编号: N21071709
期刊: ACS Sustainable Chemistry & Engineering
作者: Shixin Li, Shenqing Wang, Bing Yan, Tongtao Yue
更新时间: 2021-07-17
摘要: In an aquatic environment, nanoparticles (NPs) acquire coatings of natural organic matter (NOM) that alter the fate and toxicity of NPs. However, the essential relationship between engineered NP properties and NOM assemblage that determines how NPs are modified and behave at biological interfaces remains unclear. Herein, we use a complementary experimental and molecular dynamics approach to elucidate the mechanisms underlying adsorption of humic acid (HA) on NPs of different surface properties and effects on NP interactions with bacteria. Our results demonstrate that hydrophobic and positively charged NPs are more capable of adsorbing HAs in unique standing or lying conformations that expose particular groups to modify NP properties. In particular, HA adsorption increases effective NP size, reduces NP’s hydrophobicity, and reverses NP’s surface charge. As a consequence of HA adsorption, the binding of NPs to bacteria is sterically hindered and suppressed by electrostatic repulsion between negatively charged groups in adsorbed HAs and lipopolysaccharide on the bacterial membrane. The toxicity of NPs is mitigated as seen by reductions of NP association with bacteria and NP-induced membrane damage. These findings provide compelling explanations on the cascading events from dictation of HA adsorption by engineered NP properties to how the modified NP surfaces change their toxicity.

17572. 题目: Spatial distribution and co-occurrence of aerobic ammonia oxidation and anaerobic ammonium oxidation activities in the water-soil interface, bulk, and rhizosphere regions of paddy soil
文章编号: N21071708
期刊: Plant and Soil
作者: Jie Xu, Cheng Han, Yunbin Jiang, Wenhui Zhong
更新时间: 2021-07-17
摘要: Purpose Aerobic ammonia oxidation often couples with anaerobic ammonium oxidation (anammox) in natural ecosystems; however, their in situ activities and relative contributions are still unclear. Methods We evaluated in situ activities of both processes in the water-soil interface, bulk, and rhizosphere regions of paddy soil by 15N stable isotope. Results At the interface, we only detected aerobic ammonia oxidation activities (RA, 6.06 mmol L−1 d−1), and RA was significantly higher than in the other two regions. In the bulk soil, the RA and anammox activities (RAn) were 0.87 and 1.84 mmol L−1 d−1, respectively. In the rhizosphere soil, the RA and RAn were 0.92 and 1.17 mmol L−1 d−1, respectively. Aerobic ammonia oxidation contributed 7.0%, 5.9%, and 3.9% to the total ammonium consumption in the interface, bulk, and rhizosphere regions, respectively, while anammox contributed 13.3% and 5.3% in the bulk and rhizosphere regions, respectively. RA and RAn were positively correlated with transcript abundances of amoA and hzsB genes, respectively, rather than gene abundances. Moreover, dissolved oxygen (DO) was the most critical factor statistically influencing RA and RAn, while dissolved organic carbon (DOC) and total organic carbon (TOC) was also correlated with RAn. Conclusion Overall, we demonstrated that in situ aerobic ammonia oxidation in the interface and rhizosphere regions was more active than in the bulk soil, whereas in situ anammox was more active in the bulk soil. This study provides an increased understanding of the in situ distribution and contributions of aerobic ammonia oxidation and anammox co-occurring in complex ecosystems.

17573. 题目: Biochar boosts dark fermentative H2 production from sugarcane bagasse by selective enrichment/colonization of functional bacteria and enhancing extracellular electron transfer
文章编号: N21071707
期刊: Water Research
作者: Jie Bu, Hao-Lin Wei, Yu-Tao Wang, Jing-Rong Cheng, Ming-Jun Zhu
更新时间: 2021-07-17
摘要: The influence of biochar (BC) on anerobic digestion (AD) of organic wastes have been widely studied. However, the effect of BC on rate-limiting step during AD of lignocellulosic waste, i.e. the hydrolysis and acidogenesis step, is rarely studied and the underlying mechanisms have not been investigated. In this study, the benefits of BC with respect to dark fermentative hydrogen production were explored in a fermentation system by a heat-shocked consortium from sewage sludge (SS) with pretreated sugarcane bagasse (PSCB) as carbon source. The results showed that biochar boosted biohydrogen production by 317.1% through stimulating bacterial growth, improving critical enzymatic activities, manipulating the ratio of NADH/NAD+ and enhancing electron transfer efficiency of fermentation system. Furthermore, cellulolytic Lachnospiraceae was efficiently enriched and electroactive bacteria were selectively colonized and the ecological niche was formed on the surface of biochar. Synergistic effect between functional bacteria and extracellular electron transfer (EET) in electroactive bacteria were assumed to be established and maintained by biochar amendment. This study shed light on the underlying mechanisms of improved performance of biohydrogen production from lignocellulosic waste during mesophilic dark fermentation by BC supplementation.

17574. 题目: Coastal riverine wetland biogeochemistry follows soil organic matter distribution along a marsh-to-mangrove gradient (Florida, USA)
文章编号: N21071706
期刊: Science of The Total Environment
作者: Sarah A. Harttung, Kara R. Radabaugh, Ryan P. Moyer, Joseph M. Smoak, Lisa G. Chambers
更新时间: 2021-07-17
摘要: Many subtropical coastal wetland vegetation communities are transitioning from herbaceous marsh to woody mangrove, often facilitated by sea-level rise. This study investigated the relationships between vegetation community (upstream marsh, ecotone/transition, and downstream mangrove), salinity (S), and soil biogeochemistry in wetlands along three rivers on the Florida Gulf coast (the Little Manatee, Peace, and Fakahatchee Rivers). Vegetation was surveyed, and soil and water samples were collected during both the dry and the wet season and analyzed for biogeochemical properties (soil: bulk density, pH, organic matter, extractable inorganic and total nutrients, dissolved organic carbon (DOC), and microbial biomass carbon; water: inorganic nutrients and DOC) and processes (greenhouse gas production) while salinity and water level were continuously monitored in the field. Results indicated landscape-scale patterns in soil biogeochemistry differed significantly by river and were most strongly correlated with soil organic matter content, regardless of vegetation community or salinity regime. Contrary to expectations, soil organic matter content gradients were not always inversely related to salinity gradients, and methane production was observed in moderate- (S = 12) and high- (S = 34) salinity mangrove communities. The vegetation ecotone experienced seasonally variable salinity and did not serve as a true biogeochemical intermediate between the marsh and mangrove communities. This study demonstrates the need for site-specific studies of biogeochemical gradients in coastal wetlands and indicates the marsh-to-mangrove ecotone is not a proxy for salinity or biogeochemical tipping points. Instead, soil organic matter content is suggested as the most relevant indicator of biogeochemical properties and processes in wetlands along coastal rivers, superseding vegetation community or salinity.

17575. 题目: Leaching behavior of polycyclic aromatic hydrocarbons (PAHs) from oil-based residues of shale gas drill cuttings
文章编号: N21071705
期刊: Environmental Pollution
作者: Bingxin Xie, Jihong Qin, Hui Sun, Shu Wang, Xin Li
更新时间: 2021-07-17
摘要: Cuttings are the main solid residues which are generated from drilling operations. Due to the presence of heavy and radioactive elements, the environment risk posed by cuttings has attracted increasing attention. In this work, a short-term static immersion experiment was carried out to investigate the leaching of polycyclic aromatic hydrocarbons (PAHs) from oil-based residues of shale gas drilling cuttings. Furthermore, the effects of some relevant environmental factors controlling the leaching behavior were evaluated, including the different particle sizes, pH, extraction time, solid-to-liquid (S/L) ratio and dissolved organic matter (DOM) concentration. The results showed that (1) the concentrations of leached PAHs gradually increased with prolonged leaching time, but the cumulative amount of PAHs released during leaching was less than 3% of the total. (2) The Elovich, parabolic diffusion and power function models were found to fit the experimental data better than the first-order kinetic equation, indicating that the leaching of PAHs was controlled by the coupling of diffusion and chemical reactions at the source surface. (3) Different environmental factors had different impacts on the leaching of PAHs: the shaking time and presence of DOM increased leachability, the particle size and S/L ratio decreased leachability, and the pH did not affect the leachability of PAHs. Therefore, PAHs leaching was a complex process, and it is of scientific and environmental interest to conduct the leaching tests under the simulated environmental conditions.

17576. 题目: Evaluation of biochar addition and circulation control strengthening measures on efficiency and microecology of food waste treatment in anaerobic reactor
文章编号: N21071704
期刊: Journal of Environmental Management
作者: Lijian Zhao, Chengyuan Su, Anliu Wang, Pengfei Wang, Zhuxi Chen, Xian Huang, Menglin Chen
更新时间: 2021-07-17
摘要: The process of strengthening an expanded granular sludge blanket (EGSB) reactor under ammonia nitrogen stress conditions and by adopting three strengthening measures, namely, opening the circulation (OC), adding modified biochar (MB), adding modified biochar along with opening the circulation (MBOC), to treat food waste was studied. When the ammonia nitrogen concentration of influent increased to 1200 mg/L, the removal rate of COD reduced to about 75%, while the removal rate of ammonia nitrogen was about 6%. The average COD removal rate of the anaerobic reactor in the last 5 days of each operating cycle i.e. OC, MB and MBOC, was 85.51%, 84.11% and 90.03%, respectively. At the 30th day of each treatment-OC, MB and MBOC, the protease content in the sludge was 44.61, 42.47, 46.24 NH2–N (mg)/mg, respectively. and the content of coenzyme F420 was 0.244, 0.217 and 0.267 mmol/g, respectively. Proteobacteria was the most abundant phylum in the stage I (OC), reaching 34.36%. It was accounted for 16.68% and 21.38%, respectively, in the stage II (MB) and stage III (MBOC). The dominant archaea in the three stages were Methanosaeta, whose abundance was 38.98% in stage I, which increased to 64.94% and 64.01% in stage II and III, respectively. Among the active carbohydrate enzymes, the gene abundance of Glycoside transferases in the MBOC stage was the largest among the three stages.

17577. 题目: Application of co-pyrolysis biochar for the adsorption and immobilization of heavy metals in contaminated environmental substrates
文章编号: N21071703
期刊: Journal of Hazardous Materials
作者: Yuanling Li, Han Yu, Lina Liu, Hongbing Yu
更新时间: 2021-07-17
摘要: Heavy metal pollution has been considered as a serious threat to the environment and human in the past decades due to its toxic and unbiodegradable properties. Recently, extensive studies have been carried out on the removal of heavy metals, and various adsorption materials have been successfully developed. Among, biochar is a promising option because of its advantages of various biomass sources, abundant microporous channels and surface functional groups, as well as its attractive economic feasibility. However, the application of pristine biochar is limited by its low adsorption capacity and nonregenerative property. Co-pyrolysis biochar, produced from the pyrolysis of biomass with the addition of another biomass or non-biomass precursor, is potential in overcoming the limitation of pristine biochar and achieving superior performance for heavy metal adsorption and immobilization. Therefore, this article summarizes the recent advances in development and applications of co-pyrolysis biochar for adsorption and immobilization of various heavy metals in contaminated environmental substrates. In details, the production, characteristics and advantages of co-pyrolysis biochar are initially presented. Subsequently, the adsorption behaviors and mechanisms of different heavy metals (including Hg, Zn, Pb, Cu, Cd, Cr, As, etc.) in flue gas and wastewater by co-pyrolysis biochar are reviewed, as well as factors influencing their adsorption capacities. Meanwhile, the immobilization of heavy metals in both biochar itself and contaminated soils by co-pyrolysis biochar is discussed. Finally, the limitations of current studies and future prospects are proposed. It aims at providing a guideline for the exploitation and application of cost-effective and environmental-friendly co-pyrolysis biochar in the decontamination of environmental substrates.

17578. 题目: Semi-enclosed bays serve as hotspots for black carbon burial: A case study in Jiaozhou Bay, western Yellow Sea
文章编号: N21071702
期刊: Science of The Total Environment
作者: Na Feng, Weifeng Yang, Xiufeng Zhao, Min Chen, Yusheng Qiu, Minfang Zheng
更新时间: 2021-07-17
摘要: The provenance of black carbon (BC) and its role in affecting contaminant cycling in both the atmosphere and aquatic environments have been extensively studied. However, the fate and cycling dynamics of BC, particularly in marine environments, are poorly understood. Herein, soot BC was determined in the semi-enclosed Jiaozhou Bay to examine the seasonal variability, residence timescale in seawater, and settling flux to sediments, together with particle-reactive 234Th. Soot BC ranged from 0.39 to 4.26 μmol-C L−1. On average, spring produced the highest value of 1.88 ± 0.31 μmol-C L−1, followed by winter (1.59 ± 0.18 μmol-C L−1), summer (0.94 ± 0.09 μmol-C L−1), and autumn (0.90 ± 0.09 μmol-C L−1). The seasonality of soot BC was similar to the activity concentration of particulate 234Th (i.e., 234ThP). The close relationships between soot BC and 234ThP (p < 0.01) provide the basis for the application of 234Th to trace the fate of soot BC. Based on the 234Th deficit with respect to 238U, the residence times of soot BC were estimated to be 41 ± 6 d and 36 ± 5 d for May–August and August–November, respectively. The shorter residence times of soot BC than that of seawater indicated that soot BC delivered to Jiaozhou Bay settled in the local sediments. Furthermore, soot BC concentrations were higher in the inflow seawater from the Yellow Sea than the outflow water from Jiaozhou Bay, implying a net input of soot BC from the Yellow Sea to Jiaozhou Bay. The soot BC fluxes were 0.266 ± 0.035 mmol-C m−2 d−1 and 0.0472 ± 0.0065 mmol-C m−2 d−1 for May–August and August–November, respectively. From the bay-scale perspective, Jiaozhou Bay had buried 0.101 ± 0.010 Gg of soot BC each year. These results indicate that the semi-enclosed Jiaozhou Bay acts as an effective trap for soot BC and particle-reactive contaminants.

17579. 题目: Source, sink and preservation of organic matter from a machine learning approach of polar lipid tracers in sediments and soils from the Yellow River and Bohai Sea, eastern China
文章编号: N21071701
期刊: Chemical Geology
作者: Keyu Tao, Yunping Xu, Yinghui Wang, Yuntao Wang, Ding He
更新时间: 2021-07-17
摘要: Transport and transformation of organic matter (OM) from the river to the marginal sea is a significant part of the global carbon cycle. Biomarkers are of indispensable advantage in precisely identifying the origin of OM that is crucial to understand the organic carbon cycle. Application of more biomarker molecules with mutually confirmable information commonly implies stricter constraint of the source but also brings challenges to the data analysis and interpretation due to a large amount of molecular information. Here we used random forest (RF) classification models to analyze 123 polar lipid biomarkers of six categories, including fatty alcohols, fatty acids, alkan-2-ones, steroids, triterpenoids, and 1-O-monoalkylglycerol ethers (MAGEs) from the sediments and soils in the Yellow River and the Bohai Sea of eastern China. The environmental specificity of biomarkers was assessed based on the effective distinguishment of samples from different habitats by RF models. The sources of polar lipid biomarkers were constrained according to their environmental specificity, and four genetic classifications, i.e., bacteria, algae and zooplankton, terrestrial higher plants, and anthropogenic input were identified. The spatial distribution of OM sources provides a reasonable scheme of the sink for biospheric OM in this typical “land-river-ocean” system. A type of MAGEs as the most important variables for the RF models was effectively used to be a potential bottom-water oxygen proxy to assess the preservation of OM, and ca. 37% of marine in-situ fresh OM was estimated to decompose under varying redox conditions in the surface sediments of Bohai Sea.

17580. 题目: Ultrafast Energy Transfer Determines the Formation of Fluorescence in DOM and Humic Substances
文章编号: N21071621
期刊: Environmental Science & Technology
作者: Boris P. Yakimov, Anna A. Rubekina, Gleb S. Budylin, Alexander Y. Zherebker, Victor O. Kompanets, Sergey V. Chekalin, Yuri G. Vainer, Victor V. Fadeev, Maxim Y. Gorbunov, Irina V. Perminova, Evgeny A. Shirshin
更新时间: 2021-07-16
摘要: Humification is a ubiquitous natural process of biomass degradation that creates multicomponent systems of nonliving organic matter, including dissolved organic matter (DOM) and humic substances (HS) in water environments, soils, and organic rocks. Despite significant differences in molecular composition, the optical properties of DOM and HS are remarkably similar, and the reason for this remains largely unknown. Here, we employed fluorescence spectroscopy with (sub)picosecond resolution to elucidate the role of electronic interactions within DOM and HS. We revealed an ultrafast decay component with a characteristic decay lifetime of 0.5–1.5 ps and spectral diffusion originating from excitation energy transfer (EET) in the system. The rate of EET was positively correlated to the fraction of aromatic species and tightness of aromatic species packing. Diminishing the number of EET donor–acceptor pairs by reduction with NaBH4 (decrease of the acceptor number), decrease of pH (decrease of the electron-donating ability), or decrease of the average particle size by filtration (less donor–acceptor pairs within a particle) resulted in a lower impact of the ultrafast component on fluorescence decay. Our results uncover the role of electronic coupling among fluorophores in the formation of DOM and HS optical properties and provide a framework for studying photophysical processes in heterogeneous systems of natural fluorophores.