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24761. 题目: Effect of humic acid on Se and Fe transformations in soil during waterlogged incubation
文章编号: N19051902
期刊: Science of The Total Environment
作者: Jianxin Fan, Guoliang Zhao, Jiaoxia Sun, Ying Hu, Tujin Wang
更新时间: 2019-05-19
摘要: Humic acid (HA) serves as electron donor and acceptor in the biogeochemical cycle of Fe and Se in soil. In anoxic condition, a series of redox reactions occur, including reductive dissolution of Fe oxides, decomposition of organic matters, and transformation of trace elements. Thus, this study demonstrates the effect of HA on Se and Fe transformations in soil during waterlogged incubation. Soils were incubated under anoxic condition for 56 days, and pH, redox potential (Eh), and Fe and Se concentrations were measured at specific reaction times (days 2, 4, 8, 15, 28, and 56 of incubation). Moreover, sequential extraction and X-ray photoelectron spectroscopy (XPS) were used to obtain Se and Fe transformations, respectively. High resolution transmission electron microscopy (HR-TEM) was used to observe the morphology properties of soil. Results indicated that 4% HA addition decreased the pH and inhibited Eh decline continuously, and HA addition inhibited the Fe and Se release from soil. The Se concentration in soil solution without and with 4% HA addition at the day 15 of incubation were 1.05 mg L−1 and 0.30 mg L−1, respectively. Moreover, the residual Se fraction in soil with HA addition was evidently more than that in soil without HA addition. XPS of Se3d and Fe2p revealed that the binding energy of the main peak shifted to low values and the peak shape varied with the increase in HA addition. XPS2p3/2 and HR-TEM data indicated that the surface structure of Fe oxides in soil varied with the variations in anoxic incubation time and HA addition amount. HA addition would negatively influence Se and Fe release in soil solution and then reduce their bioavailability. This study aids in understanding the environmental behavior changes of Se and Fe when high HA concentrations enter the soils, especially wetland or paddy soil.
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24762. 题目: Sorption of lead in soil amended with coconut fiber biochar: Geochemical and spectroscopic investigations
文章编号: N19051901
期刊: Geoderma
作者: Jianhong Li, Shan-Li Wang, Lirong Zheng, Dongliang Chen, Zhipeng Wu, Yu Xie, Weidong Wu, Nabeel Khan Niazi, Yong Sik Ok, Jörg Rinklebe, Hailong Wang
更新时间: 2019-05-19
摘要: In this study, we applied coconut fiber-derived biochar (CFB) to a lead (Pb)-contaminated soil (at 600 mg kg−1) at 2% and 4% (w/w), in order to explore the efficacy and mechanism of CFB to immobilize Pb in soil during a 150-day incubation experiment. Our approach integrated various techniques namely micro-X-ray fluorescence, sequential extraction, X-ray absorption fine structure, scanning electron microscopy combined with energy dispersive X-ray spectroscopy to evaluate the Pb immobilization. Results indicated that the distribution of Pb in the studied soil was significantly affected by CFB application. The Pb content in organic matter bound fraction of the studied soil increased by 29.5% and 33.5% with 2% and 4% CFB, respectively, compared to control soil after 150-day of incubation. Lead-loaded humic acid (HA) and Pb3(PO4)2 were higher in the biochar-amended soil (2% CFB) as compared with the control soil. The CFB particles possibly offer more binding sites of PO43− and carboxylic functional groups than the binding sites of –FeO(OH), SiO32−, −Al2O3 and organic functional groups provided by the original soil particles alone (no biochar) for Pb. Overall, this study highlights that CFB can be a potential candidate to immobilize Pb for the restoration and remediation of Pb-contaminated soils.
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24763. 题目: Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models
文章编号: N19051819
期刊: Environmental Science & Technology
作者: Tara Marie Schendorf, Rossana Del Vecchio, Marla Bianca, Neil V. Blough
更新时间: 2019-05-18
摘要: The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.
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24764. 题目: The budget of macrobenthic reworked organic carbon ‐ a modelling case study of the North Sea
文章编号: N19051818
期刊: Journal of Geophysical Research: Biogeosciences
作者: Wenyan Zhang, Kai Wirtz, Ute Daewel, Alexa Wrede, Ingrid Kröncke, Gerhard Kuhn, Andreas Neumann, Julia Meyer, Mengyao Ma, Corinna Schrum
更新时间: 2019-05-18
摘要: The importance of macrobenthos in benthic‐pelagic coupling and early diagenesis of organic carbon (OC) has long been recognized but has not been quantified at a regional scale. By using the southern North Sea as an exemplary area we present a modelling attempt to quantify the budget of total organic carbon (TOC) reworked by macrobenthos in seafloor surface sediments. Vertical profiles in sediments collected in the field indicate a significant but nonlinear correlation between TOC and macrobenthic biomass. A mechanistic model is used to resolve the bi‐directional interaction between TOC and macrobenthos. A novelty of this model is that bioturbation is resolved dynamically depending on variations in local food resource and macrobenthic biomass. The model is coupled to 3D hydrodynamic‐biogeochemical simulations to hindcast the mutual dependence between sedimentary TOC and macrobenthos from 1948 to 2015. Agreement with field data reveals a satisfactory model performance. Our simulations show that the preservation of TOC in the North Sea sediments is not only determined by pelagic conditions (hydrodynamic regime and primary production) but also by the vertical distribution of TOC, bioturbation intensity, and the vertical positioning of macrobenthos. Macrobenthos annually ingest 20%–35% and in addition vertically diffuse 11%–22% of the total budget of TOC in the upper‐most 30 cm sediments in the southern North Sea. This result indicates a central role of benthic animals in modulating the OC cycling at the sediment‐water interface of continental margins.
24765. 题目: Leaf leachates have the potential to influence soil nitrification via changes in ammonia‐oxidizing archaea and bacteria populations
文章编号: N19051817
期刊: European Journal of Soil Science
作者: W. B. Chen, B. M. Chen, H. X. Liao, J. Q. Su, S. L. Peng
更新时间: 2019-05-18
摘要: Soil nitrogen (N) transformation is mainly controlled by microorganisms. Different plant species have specific effects on soil ammonia‐oxidizing archaea (AOA) and bacteria (AOB). Furthermore, plant secondary metabolites have dramatic influences on soil N transformation and soil ammonia‐oxidizers. However, no study has directly linked the changes in soil AOA and AOB communities to N transformation due to different plant species' leaf leachates, including comparing invasive versus native plants. We selected three invasive species, Wedelia trilobata, Ipomoea cairica and Mikania micrantha, and two native species, Wedelia chinensis and Merremia hederacea, and incubated soil with high and low concentrations of leaf leachates from the five species. Soil N transformation and ammonia oxidizer communities (based on quantitative PCR and 16S rRNA high‐throughput sequencing) were determined. Leaf leachates significantly affected soil N transformation and soil AOA and AOB abundance, and the effects were dependent on the plant species and leachate concentration. The leachate of W. chinensis increased soil net nitrification rates (NNR), while that of M. micrantha increased soil nitrate (NO3−) and NNR. The leachate of M. micrantha increased AOB amoA genes, while that of M. hederacea decreased AOA amoA genes. At the higher concentration, all leachates showed inhibitory effects on the relative abundance of all AOA taxonomic groups. Phenolics, flavonoids and organic carbon in leaf leachates had a negative correlation with soil NO3−, NNR and the amoA genes of AOA and AOB, whereas NH4+ and NO3− in leachates showed a positive correlation. Among the five species, invasive species M. micrantha had the strongest positive effect on soil N transformation and AOB abundance. The altered soil ammonia oxidizer communities and modified N process rates induced by leaf leachates provide an explanatory mechanism for the differential effects of plant species on N cycling.
24766. 题目: Improving soil aggregation, aggregate‐associated C and N, and enzyme activities by green manure crops in the Loess Plateau of China
文章编号: N19051816
期刊: European Journal of Soil Science
作者: Dabin Zhang, Zhiyuan Yao, Jiao Chen, Pengwei Yao, Na Zhao, Wenxiang He, Yangyang Li, Suiqi Zhang, Bingnian Zhai, Zhaohui Wang, Donglin Huang, Weidong Cao, Yajun Gao
更新时间: 2019-05-18
摘要: Green manure and fertilization practices have substantial impacts on soil chemical and biological properties over time. A field experiment was conducted on Cumulic Haplustoll to investigate the effects of leguminous green manure (LGM) crops and N fertilizer on dry‐stable soil aggregates distributions and stability, the concentrations of organic carbon (OC) and N in the bulk soil and separated aggregate fractions, and soil enzyme activities in dry croplands on the Loess Plateau of China. Species tested as LGM crops were Huai bean (Glycine ussuriensis Regel et Maack.), soybean (G. max (L.) Merr.) and mung bean (Phaseolus radiatus L.). Two rates of N fertilizer (0 & 162 kg N·ha−1) applied to winter wheat sown after LGM was incorporated into surface soil. Results showed that the inclusion of LGM crops for 6‐yr significantly increased the total nitrogen (TN), soil organic carbon (SOC), aggregate‐associated N and OC concentrations, enhanced the values of aggregate content with >0.25 mm size (R0.25) and mean weight diameter (MWD), and boosted soil enzyme (invertase, urease, dehydrogenase and aryl‐sulfatase) activities at the 0–20 cm depth compared to the bare fallow system under dryland conditions. The long‐term application of N fertilizer substantially increased the proportion of macro‐aggregates (>5.0 mm), MWD and N contents in the 0.25–5 mm aggregates, and promoted the relative activities of invertase, alkaline phosphatase, dehydrogenase and aryl‐sulfatase, but decreased the urease activity. The correlations among macro‐aggregate fractions and soil chemical properties, aggregate stability and enzyme activities were significant and positive, however, the correlations between small aggregate fractions (<2 mm) and corresponding parameters were negative, or there were no correlations. Overall, combining green manuring practice with suitable N fertilizer application should be recommended to improve the soil quality in dryland regions similar to the Loess Plateau of China.
24767. 题目: Effects of Rhizophagus clarus and biochar on growth, photosynthesis, nutrients, and cadmium (Cd) concentration of maize ( Zea mays ) grown in Cd-spiked soil
文章编号: N19051815
期刊: Environmental Science and Pollution Research
作者: Mazhar Rafique, Ibrahim Ortas, Muhammad Rizwan, Tariq Sultan, Hassan Javed Chaudhary, Mehmet Işik, Oğuzhan Aydin
更新时间: 2019-05-18
摘要: Cadmium (Cd) toxicity in agricultural crops is a widespread problem. Little is known about biochar and arbuscular mycorrhizal fungi (AMF) effect on Cd concentration in maize plant either applied separately or in combination. Current study was performed to demonstrate effects of biochar and Rhizophagus clarus on plant growth, photosynthesis activity, nutrients (P, Ca, Mg, Fe, Cu, and Mn), and Cd concentration in maize grown in Cd-spiked soil. The alkaline soil was spiked by Cd factor at three levels: 0 (Cd 0), 5 (Cd 5), and 10 (Cd 10) mg/kg; biochar factor at two levels: 0 and 1%; and mycorrhizal inoculum factor at two levels: MF0 and MF1 (R. clraus). Plants were harvested after 70 days of seed germination, and various morphological and physiological parameters, as well as elemental concentration and root colonization, were recorded. Addition of biochar increased plant biomass by 21% (Cd 5) and 93% (Cd 10), MF1 enhanced by 53% (Cd 0) and 69% (Cd 10), while biochar + MF1 enhanced dry plant biomass by 70% (Cd 0) and 94% (Cd 10). Results showed maximum increase of 94% (Cd 10) in plant biomass was observed in Cd-spiked soil. Root colonization decreased proportionally by increasing Cd concentration and at Cd 10, colonization was 36.7% and 31.7% for MF1 and biochar + MF1 treatments, respectively. Besides that, addition of biochar enhanced root attributes (root length, volume, and surface area) by 34–58% compared to control in Cd 10. The MF1 increased these attributes by 11–78% while biochar + MF1 enhanced by 32–61% in Cd-spiked soil. However, biochar + MF1 neutralized Cd stress in maize plant for gaseous attributes (assimilation rate, transpiration rate, intercellular CO2, and stomatal conductance). The MF1 enhanced Cd concentration in plant as it was 3.32 mg/kg in Cd 5 and 6.73 mg/kg in Cd 10 treatments while addition of biochar phytostabilized Cd and reduced its concentration in plants by 2.0 mg/kg in Cd 5 and 4.27 mg/kg in Cd 10. The biochar + MF1 had 2.9 mg/kg and 4.8 mg/kg Cd concentration in Cd 5 and Cd 10 plants, respectively. Phosphorus concentration was augmented in shoots (up to 26%) and roots (up to 20%) of maize plant in biochar-amended soil than control plants. In biochar + MF1, concentration of P was 1.01% and 0.73% in Cd 5 and Cd 10, respectively. It is concluded that biochar + MF1 treatment enhances plant biomass while addition of sole biochar reduced Cd uptake, slightly indifferent to earlier treatment.
24768. 题目: The role of photodegradation in the environmental fate of hydroxychloroquine
文章编号: N19051814
期刊: Chemosphere
作者: Dario Dabić, Sandra Babić, Irena Škorić
更新时间: 2019-05-18
摘要: For many organic pollutants present in surface waters, photolysis is considered as a major abiotic degradation process. The present study aimed to explore the role of photolysis in the environmental fate of hydroxychloroquine (HCQ) for the first time. The photolytic degradation of HCQ was investigated under simulated solar radiation (300–800 nm) in ultrapure, spring, river, and sea water. The effect of pH on the photodegradation rate was substantial and it was observed that degradation was faster at higher pH-values. Obtained half-lives ranged from 5.5 min at pH 9 to 23.1 h at pH 4. Humic acids, nitrate and iron(III) enhanced photodegradation of HCQ due to formation of hydroxyl radicals and its attack on HCQ molecule. In contrast, chloride, sulfate and bromide inhibited photodegradation. Additionally, the humic acids exhibited a dual role, photosensitization and inner filter effect. The study of the reaction kinetics was performed with HPLC-PDA, while the identification of degradation products formed during photolytic degradation was carried out using HPLC-MS/MS and NMR spectroscopy. The hydroxylation was recognized as the dominant path of photoproducts formation. The results of this research reveal the importance of photolytic degradation in environmental fate of HCQ and enable a better understanding of its behavior in the environment. Moreover, the results showing the significant effect of pH on the photodegradation of HCQ can be very useful in water treatment processes.
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24769. 题目: Biodegradation and photooxidation of phenolic compounds in soil—A compound-specific stable isotope approach
文章编号: N19051813
期刊: Chemosphere
作者: Zacharias Steinmetz, Markus P. Kurtz, Jochen P. Zubrod, Armin H. Meyer, Martin Elsner, Gabriele E. Schaumann
更新时间: 2019-05-18
摘要: Phenolic compounds occur in a variety of plants and can be used as model compounds for investigating the fate of organic wastewater, lignin, or soil organic matter in the environment. The aim of this study was to better understand and differentiate mechanisms associated with photo- and biodegradation of tyrosol, vanillin, vanillic acid, and coumaric acid in soil. In a 29 d incubation experiment, soil spiked with these phenolic compounds was either subjected to UV irradiation under sterile conditions or to the native soil microbial community in the dark. Changes in the isotopic composition (δ13C) of phenolic compounds were determined by gas chromatography–isotope ratio mass spectrometry and complemented by concentration measurements. Phospholipid-derived fatty acid and ergosterol biomarkers together with soil water repellency measurements provided information on soil microbial and physical properties. Biodegradation followed pseudo-first-order dissipation kinetics, enriched remaining phenolic compounds in 13C, and was associated with increased fungal rather than bacterial biomarkers. Growing mycelia rendered the soil slightly water repellent. High sample variation limited the reliable estimation of apparent kinetic isotope effects (AKIEs) to tyrosol. The AKIE of tyrosol biodegradation was 1.007 ± 0.002. Photooxidation kinetics were of pseudo-zero- or first-order with an AKIE of 1.02 ± 0.01 for tyrosol, suggesting a hydroxyl-radical mediated degradation process. Further research needs to address δ13C variation among sample replicates potentially originating from heterogeneous reaction spaces in soil. Here, nuclear magnetic resonance or nanoscopic imaging could help to better understand the distribution of organic compounds and their transformation in the soil matrix.
24770. 题目: Storage of organic carbon in the soils of Mexican temperate forests
文章编号: N19051812
期刊: Forest Ecology and Management
作者: Nadia S. Santini, María Fernanda Adame, Rachael H. Nolan, Yosune Miquelajauregui, Daniel Piñero, Alicia Mastretta-Yanes, Ángela P. Cuervo-Robayo, Derek Eamus
更新时间: 2019-05-18
摘要: The deforestation and degradation of natural habitats is the second largest contributor to carbon dioxide (CO2) emissions to the atmosphere. Temperate forests cover ∼16.5% of the Mexican landscape, and are a priority ecosystem for global conservation due to their high rate of endemism and species diversity. These forests also provide valuable ecosystem services, including the storage of organic carbon. Mexican temperate forests have lost more than half of their original cover, with ongoing forest degradation, resulting in CO2 emissions to the atmosphere. Most studies and carbon inventories only consider organic carbon stored in the aboveground biomass, and do not consider the organic carbon stored within soils of temperate forests. As a result, the emissions of CO2 due to deforestation are underestimated, and the value of temperate forests is underappreciated. To address this shortcoming, (1) we examine the extent and factors determining soil organic carbon stocks; (2) we estimate soil organic carbon stocks of Mexican temperate forests, the CO2 emissions caused by deforestation and avoided emissions from conservation and (3) we discuss the causes of loss of soil OC and management strategies to mitigate this loss. We propose that including the soil organic carbon stock-component is a priority for national projects targeting reducing emissions from deforestation. Also, urgent studies on the impacts of forest degradation in stocks of soil organic carbon are needed. Management strategies for conservation and rehabilitation of Mexican temperate forests must consider social and economic aspects of the local communities.
24771. 题目: Estimation of soil organic matter content by modeling with artificial neural networks
文章编号: N19051811
期刊: Geoderma
作者: Mariele Monique Honorato Fernandes, Anderson Prates Coelho, Carolina Fernandes, Matheus Flavio da Silva, Claudia Campos Dela Marta
更新时间: 2019-05-18
摘要: Soil organic matter has direct relationship with soil fertility and quality. However, its estimation in laboratory generates chemical residues which can contaminate the environment, and more ecological methods to determine the soil organic matter present high costs to the laboratories. This study aimed to evaluate the accuracy of artificial neural networks (ANNs) in estimating soil organic matter content from soil chemical attributes and to indicate whether network complexity affects estimation accuracy. A database was created containing 8556 samples, and 75% of the data were used for calibration and 25% for validation of the models. The variables used were: pH, potassium, phosphorus, calcium, magnesium and potential acidity. However, potassium and phosphorus were removed from the input variables. The ANNs were from the Multilayer Perceptron class, with two hidden layers, each of which had number of neurons ranging from 4 to 20. The 15 ANNs with lowest root mean square error (RMSE) were randomly presented by the program Statistica7®, and 6 of them were chosen for accuracy assessment. The fits were tested by analysis of variance (F test) and accuracy was assessed based on the coefficient of determination (R2), RMSE, mean error (ME), index of agreement (d) and confidence coefficient (c). The ANNs showed high accuracy to estimate soil organic matter in the phases of both calibration (R2 = 0.92; RMSE = 1.82 g kg−1) and validation (R2 = 0.76; RMSE = 1.98 g kg−1). Less complex networks can be trained and show the same accuracy as more complex networks.
24772. 题目: A comparative analysis of ball-milled biochar, graphene oxide, and multi-walled carbon nanotubes with respect to toxicity induction in Streptomyces
文章编号: N19051810
期刊: Journal of Environmental Management
作者: Xiaomei Liu, Jingchun Tang, Lan Wang, Qinglong Liu, Rutao Liu
更新时间: 2019-05-18
摘要: Ball-milled biochar has recently attracted a lot of attention due to the simplicity of its preparation and low cost. However, it is unknown if the biochar is environmentally safe. Here, the toxic effect of ball-milled biochar on Streptomyces was compared to that of pristine biochar and two other carbon nanomaterials of different shapes—graphene oxide and multi-walled carbon nanotubes. The effect of these different materials on antibiotic production was characterized. The results showed that even at concentrations of up to 10 mg/L, pristine biochar had a negligible effect on toxicity and antibiotic production in Streptomyces. However, after ball milling, the physical and chemical properties of biochar changed dramatically. Cells were severely damaged, and there was a significant increase in antibiotic production after the addition of ball-milled biochar. Exposure to 10 mg/L of ball-milled biochar caused massive cell disruption; the survival rate of Streptomyces coelicolor M145 cells was only 68.2% as compared to 90% after treatment with 10 mg/L graphene oxide and multi-walled carbon nanotubes. The secretion of the antibiotics— the red intracellular pigment undecylprodigiosin (RED) and blue diffusible pigment actinorhodin (ACT) was enhanced with the highest level in treatment with ball milled biochar, as compared to that with the other two carbon nanomaterials. This effect can be attributed to increased expression of pathway-specific regulatory genes redD, redZ and actⅡ-ORF4. Ball-milled biochar can be developed as an effective additive to increase antibiotic yield. However, we should restrict the large-scale use of ball-milled biochar before fully understanding its impact on the environment and human health.
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24773. 题目: Synthesis of carbon nanotubes using biochar as precursor material under microwave irradiation
文章编号: N19051809
期刊: Journal of Environmental Management
作者: Pamela Hildago-Oporto, R. Navia, R. Hunter, G. Coronado, M.E. Gonzalez
更新时间: 2019-05-18
摘要: Biochar is a carbon-rich porous material obtained by the thermochemical treatment of biomass. Biochar presents a suitable composition as precursor material for carbon nanotubes (CNTs) growth, and can be used as a sustainable alternative in the valorization of biomass. In this study, the synthesis of CNTs using biochar as biological precursor material is presented. CNTs were synthesized using a mixture of biochar and ferrocene including microwave assisted heating. Biochar samples used in the synthesis of CNTs were obtained from agroindustrial waste such as wheat straw, oat hulls, rapeseed cake and hazelnut hulls pyrolyzed at 400 °C and 600 °C. Synthesized CNTs were examined by dynamic light scattering, UV-VIS spectroscopy, Raman spectroscopy and transmission electron microscopy. The results indicate that the physicochemical properties of CNTs were influenced by pyrolysis temperature of biomass. Biochars obtained at 600 °C produced higher CNTs concentration and smaller hydrodynamic diameter. Moreover, CNTs synthesized from biochar of hazelnut hulls and wheat straw show a higher degree of wall graphitization, suggesting superior CNT quality. The results of this study show the feasible production of CNTs using biochar as precursor material.
24774. 题目: Agro-environmental impacts, carbon sequestration and profit analysis of blended biochar pellet application in the paddy soil-water system
文章编号: N19051808
期刊: Journal of Environmental Management
作者: JoungDu Shin, EunSuk Jang, SangWon Park, Balasubramani Ravindran, Soon Woong Chang
更新时间: 2019-05-18
摘要: The application of biochar pellet blended with pig manure compost was investigated to estimate its agro-environmental impacts and to evaluate its soil carbon sequestration and profit analysis during rice cultivation. The experiment consisted of four different treatments such as control as pig manure compost only, pig manure compost pellet (PMCP), biochar pellet blended with biochar and pig manure compost (4: 6 ratios, BCP), and slow release fertilizer (SRF). The application of chemical fertilizer and pig manure compost in the whole treatment except the BCP were 90-45-57 kg ha−1 (N-P-K) and 2600 kg ha−1, respectively, based on the recommended rates for rice cultivation at National Institute of Agricultural Sciences (NIAS). The BCP and SRF were applied with N 90 kg ha−1 basis only as basal application before transplanting. The pig manure compost, phosphorous and potassium were applied at basal application while nitrogen fertilizer was applied with three separations as basal and two additional applications. Results showed that concentrations of ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N) in the BCP at an early stage of rice growth were lowest among the treatments, but their concentrations in the paddy water rapidly decreased at 21 days after transplanting. For paddy soil, NH4-N concentration in the SRF was continuously high compared to the BCP until 20 days of rice cultivation. For paddy water, phosphate phosphorous (PO4-P) concentrations in the BCP were three fold lower than the SRF at an early stage of rice growth. Similar pattern between potassium (K) concentrations in paddy water and potassium oxide (K2O) contents in surface soil was also observed during rice cultivation where their concentrations decreased abruptly 41 days after transplanting. Carbon sequestration and mitigation of carbon dioxide equivalency (CO2-eq.) emission in the BCP were higher at 1.65 tons ha−1 and 6.06 tons ha−1, respectively, than the control while result of its profit analysis was $145.59 (KAU, Korean Allowance Unit) per hectare during rice cultivation. The rice yield were not significantly different (p > 0.05) among all treatments.
24775. 题目: A compost-derived thermophilic microbial consortium enhances the humification process and alters the microbial diversity during composting
文章编号: N19051807
期刊: Journal of Environmental Management
作者: Jiaqi Xu, Zhiwei Jiang, Mingqi Li, Qunliang Li
更新时间: 2019-05-18
摘要: This work was conducted to assess the influence of a compost-born multifunctional thermophilic microbial consortium (CTMC) on the physico-chemical parameters, organic matter (OM) transformation and dynamic succession of microbial communities in dairy manure-sugarcane leaves co-composting. The results revealed that CTMC inoculation not only improved the bio-degradation of OM and lignocellulose but also distinctly enhanced the aromaticity and stability degrees of dissolved organic matter and humic substance (HS). Additionally, the complexity and diversity of bacterial and fungal community increased after inoculation. Redundancy analysis indicated that the microbial communities compositions and the physico-chemical parameters interacted with each other in humification process. The dominated bacterial and fungal species related to lignocellulose degradation and humification process were also detected. Accordingly, this research could put forward a possible optimized inoculation strategy to enhance the mineralization of organic carbon, accelerate the lignocellulose degradation and promote the humification process in solid organic waste composting.
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24776. 题目: Organic carbon source-dependent properties of soluble microbial products in sequencing batch reactors and its effects on membrane fouling
文章编号: N19051806
期刊: Journal of Environmental Management
作者: Quang Viet Ly, Long D. Nghiem, Jinwoo Cho, Tahir Maqbool, Jin Hur
更新时间: 2019-05-18
摘要: This study investigated the influence of three different organic carbon sources including sodium acetate (SOD), glucose (GLU), and starch (STAR), on soluble microbial products (SMP), which presumably have dissimilar uptake rates and metabolic pathways, in sequencing batch reactors (SBR) and their subsequent effects on membrane fouling of ultrafiltration (UF). SMP were mainly characterized by fluorescence excitation emission matrix coupled with parallel factor analysis (EEM-PARAFAC) and size exclusion chromatography (SEC). SMP produced in SOD-fed SBR showed higher abundances of protein-like fluorescent component and large sized aliphatic biopolymer (BP) than GLU- or STAR-fed counterpart did, while the STAR-based operation resulted in more SMP enriched with humic-like fluorescence. The differences in SMP exerted marked effects on UF membrane fouling as indicated by the highest fouling potential with reversibility shown for the SMP from the SOD-fed reactor. Regardless of the carbon source, BP fraction and protein-like component exhibited the greatest extent of reversible fouling, suggesting that size exclusion plays a critical role. However, notable differences in the reversible fouling propensity of relatively smaller size fractions among the three SBRs signified the possible involvement of chemical interactions as a secondary fouling mechanism and its dependency on different carbon sources. Our results provide a new insight into the roles of carbon sources in the characteristics of SMP in biological treatment systems and their effects on the post-treatment using membrane filtration, which is ultimately beneficial to the optimization of biological treatment design and membrane filtration operation.
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24777. 题目: Impact of membrane biofouling in the sequential development of performance indicators: Feed channel pressure drop, permeability, and salt rejection
文章编号: N19051805
期刊: Journal of Membrane Science
作者: Nadine Siebdrath, Nadia Farhat, Wei Ding, Joop Kruithof, Johannes S. Vrouwenvelder
更新时间: 2019-05-18
摘要: Biofouling development is affected by a variety of factors that change over the length of reverse osmosis (RO) membrane modules in pressure vessels. Spatially resolved biofouling formation was studied under conditions representative to practice using four one-meter Long Channel Membrane Test Cells (LCMTCs) in series, simulating an industrial pressure vessel.Biofouling was induced by dosing an easily assimilable substrate to the feed water. The impact of biofouling on the sequential decline of RO membrane performance indicators (feed channel pressure drop, permeability and salt rejection) was investigated. Also, the temporal organic carbon (DOC) consumption was assessed spatially over the four test cells.Results showed that all membrane performance indicators were impacted by biofouling formation. The feed channel pressure (FCP) drop increase was impacted earliest and strongest followed by permeability and salt rejection decline, underlining that FCP drop is a sensitive and early biofouling monitoring indicator. Spatially resolved biofouling investigations revealed that most biofouling was formed in the lead sections of membrane installation with a decreasing gradient over length, linked to DOC availability in the system. In this study, FCP drop played a crucial role: the FCP drop increase at the lead test cell of the membrane installation caused performance losses for the downstream test cells.Minimizing the effect of biofouling on membrane performance should be pursued by a combination of strategies involving (i) early detection and preventive cleaning, (ii) substrate limitation for delaying biofouling built-up and (iii) optimized (early) cleaning procedures for more effective biofilm removal.
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24778. 题目: Use of n-alkanes to trace erosion and main sources of sediments in a watershed in southern Brazil
文章编号: N19051804
期刊: Science of The Total Environment
作者: Carlos Eduardo Galoski, Angela Ethelis Jimenez Martinez, Gilson Bauer Schultz, Irani dos Santos, Sandro Froehner
更新时间: 2019-05-18
摘要: Erosive processes can transport sediments containing nutrients, heavy metals and contaminants of organic and inorganic origin into bodies of water, therefore affecting the local ecosystem and the population that benefits from the water sources. In order to better understand the origin of sediment sources and establish mitigation measures, the use of the sediment fingerprinting technique has been highlighted. Thus, the present work had as objective to apply n-alkanes in order to trace and understand the main sources of organic matter in sediments and associate the results with land and soil occupation. The study area is located in the municipality of Rio Negrinho - Brazil, in the Saci river basin. Soil samples were collected and classified according to their use and occupation, as well as and samples of local vegetation to be used as reference. The distribution of n-alkanes in the sediments was compared with the distribution found in the vegetation and soil. Previously, a distribution pattern of n-alkanes had been identified in all major vegetation used to trace the source of organic matter and hence the soil. The concentrations of total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and granulometry were also analyzed in the soil and sediment samples. Indexes between n-alkanes were used and applied to assess the source together with statistical analysis (PCA). In sum, the results showed that the sediments are mainly composed of Pinus taeda reforestation soils, as well as soil from the abandoned roads used to transport the cut trees, while the contribution of autochthonous sediments was found to be minimal. In this way, the fingerprint technique served as an auxiliary tool in order to establish measures for the good management of a river basin, bringing important information about the contributing sources of sediment to water bodies.
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24779. 题目: Column chromatography approach to determine mobility of fluorotelomer sulfonates and polyfluoroalkyl betaines
文章编号: N19051803
期刊: Science of The Total Environment
作者: Yue Zhi, Jinxia Liu
更新时间: 2019-05-18
摘要: Betaine-based polyfluoroalkyl surfactants are major perfluoroalkyl and polyfluoroalkyl surfactants (PFASs) found in many aqueous film-forming foams (AFFF) contaminated sites, while the transport behavior (i.e., mobility and adsorption) of PFAS-based betaines in groundwater and natural geosorbents interfaces remains unclear. To fill the knowledge gap, partitioning between of 15 AFFF-relevant PFASs, including 3 fluorotelomer sulfonates (FTSAs) and 3 polyfluoroalkyl betaines, and a model soil organic matter (SOM) were systematically assessed using a modified column chromatography approach. Results show that the retention of FTSAs (perfluoroalkyl chain-length of 4, 6, and 8) to SOM are similar to that of corresponding legacy perfluoroalkyl sulfonic acids (PFSAs) with the same chain length; FTSAs also respond to changes in solution chemistry similarly as PFSAs. At a solution pH of 5.9, based on the equilibrium speciation of the betaine-PFASs together with the experimental observations, the predominance of the neutral species over zwitterion gives rise to the relatively higher retention of polyfluoroalkyl betaines than perfluoroalkyl carboxylic acids (PFCAs) of equivalent chain-length. Sorption edges (minimal and maximum logKoc values over a defined pH range) determined for three polyfluoroalkyl betaines are: 1.90–3.81 for perfluorooctaneamide betaine (PFOAB), 2.03–2.65 for perfluoroctane sulfonamide betaine (PFOSB), and < 3.04 for 6:2 fluorotelomer sulfonamide betaine (6:2 FTAB). Moreover, the increase in pH reduces the sorption of all PFAS to SOM. Increasing calcium ion (concentration ranges from 0.5 to 50 mM) has enhanced the sorption of anionic PFASs to SOM but decreased the sorption of the polyfluoroalkyl betaines. These findings are expected to improve the ability to anticipate and predict the possible subsurface location (i.e., predominantly in groundwater or sorbed to soil) of both novel and legacy PFASs.
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24780. 题目: Quantification of soil organic carbon stock in urban soils using visible and near infrared reflectance spectroscopy (VNIRS) in situ or in laboratory conditions
文章编号: N19051802
期刊: Science of The Total Environment
作者: Victor Allory, Aurélie Cambou, Patricia Moulin, Christophe Schwartz, Patrice Cannavo, Laure Vidal-Beaudet, Bernard G. Barthès
更新时间: 2019-05-18
摘要: Urban soils, like other soils, can be sink or source for atmospheric carbon dioxide, and due to urban expansion, are receiving increasing attention. Studying their highly variable attributes requires high-density sampling, which can hardly be achieved using conventional approaches. The objective of this work was to determine the ability of visible and near infrared reflectance spectroscopy (VNIRS) to quantify soil organic carbon (SOC) concentration (gC kg−1) and stock (gC dm−3, or MgC ha−1 for a given depth layer) in parks and sealed soils of two French cities, Marseille and Nantes, using spectra collected on pit walls or in laboratory conditions (air dried, 2 mm sieved samples).Better VNIRS predictions were achieved using laboratory than in situ spectra (R2 ≈ 0.8–0.9 vs. 0.7–0.8 in validation), and for sample SOC concentration than stock (R2val up to 0.83 in situ and 0.95 in the laboratory vs. 0.78 and 0.89, respectively). Stock was conventionally calculated according to four methods that variably account for coarse particles (>2 mm); and it was better predicted when coarse particles were not taken into account. This was logical using laboratory spectra, collected on 2 mm sieved samples; but concerning in situ spectra, this suggested the operator tended to put the spectrometer beside the coarsest particles during spectrum acquisition. This point is worth considering for urban soils, often rich in coarse particles.Stocks were then aggregated at the profile level: SOC stock prediction was more accurate at profile than sample level when using laboratory spectra (R2val = 0.94 vs. 0.89, respectively), probably due to uncertainty compensation; but this was not the case when using in situ spectra, possibly because samples collected for SOC analysis and corresponding VNIRS scans were not at the exact same location.This work demonstrates VNIRS usefulness for quantifying SOC stock time- and cost-effectively, in urban soils especially.
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