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24621. 题目: Effect of the pyrolysis duration and the addition of zeolite powder on the leaching toxicity of copper and cadmium in biochar produced from four different aquatic plants
文章编号: N19080713
期刊: Ecotoxicology and Environmental Safety
作者: Zhongchuang Liu, Bangjun Lu, Benyang He, Xiang Li, Li-ao Wang
更新时间: 2019-08-07
摘要: The study aimed to determine the biochar yield of four aquatic plants, the leaching toxicity of copper (Cu) and cadmium (Cd) in the biochar, and the stabilization characteristics of the biochar produced under different pyrolysis conditions (at 350 °C for 1, 2, and 3 h and absence/presence of zeolite powder). The results showed that different plant species required a different pyrolysis duration and the presence or absence of zeolite powder. The stabilization of Cu and Cd was significantly affected by the pyrolysis duration and the external materials for different plant species and different types of admixtures. Pyrolysis temperatures over 350 °C for 1 h without zeolite powder generated stable Cu and Cd in goldfish algae (Ceratophyllum demersum L.), foxtail algae (Myriophyllum verticillatum L.), and penny grass (Hydrocotyle vulgaris). Pyrolysis temperatures over 350 °C for 1 h with zeolite powder made Cu and Cd stable in water celery (Oenanthe javanica (Bl.) DC). The addition of zeolite powder during pyrolysis was possible due to the weight reduction efficiency in plants with Cu and Cd. Furthermore, the surface of the biochar with the zeolite powder showed honeycombs and a spongy porous structure. The duration of the pyrolysis had little effect on the honeycomb pore structure.

24622. 题目: Effects of plantation age and precipitation gradient on soil carbon and nitrogen changes following afforestation in the Chinese Loess Plateau
文章编号: N19080712
期刊: Land Degradation & Development
作者: Xiaoyang Han, Guangyao Gao, Zongshan Li, Ruiying Chang, Lei Jiao, Bojie Fu
更新时间: 2019-08-07
摘要: Afforestation of degraded land significantly influences soil organic carbon (SOC) and total nitrogen (STN) sequestration. The interaction effects of plantation age and climate gradient on SOC and STN changes following afforestation are not well understood. In this study, five sites were selected along a precipitation gradient (410~600 mm yr^‐1) in the Loess Plateau. The SOC and STN stocks at a depth of 0‐200 cm were measured in cropland and black locust (Robinia pseudoacacia L.) forests with different plantation ages, i.e., young forest (<15 years), middle‐aged forest (15‐25 years) and old forest (>25 years). The SOC and STN stocks in the 0‐200 cm profiles of young forest, middle‐aged forest and cropland increased significantly with mean annual precipitation (p<0.05), while the increasing trend of the SOC stocks of old forest was not significant, indicating an age‐dependent change in the SOC and STN stocks across the precipitation gradient. The SOC stock change (∆SOC) following afforestation increased with mean annual precipitation in young forest, but it had a decreasing trend in middle‐aged and old forests. The STN stock changes (∆STN) in the three forests were negative at most sites, and they all decreased along the precipitation gradient. There were significant positive correlations between ∆SOC and ∆STN (p<0.01), and 1 g STN stock accumulation was accompanied by 8.40 g, 6.10 g and 10.48 g SOC accumulation for young forest, middle‐aged forest and old forest, respectively. The different patterns of SOC and STN stock changes should be incorporated into soil C and N modelling and estimation.

24623. 题目: Zones of influence for soil organic matter dynamics: a conceptual framework for data and models
文章编号: N19080711
期刊: Global Change Biology
作者: C. Cagnarini, E. Blyth, B.A. Emmett, C.D. Evans, R.I. Griffiths, A. Keith, L. Jones, I. Lebron, N.P. McNamara, J. Puissant, S. Reinsch, D.A. Robinson, E.C. Rowe, A.R.C. Thomas, S.M. Smart, J. Whitaker, B.J. Cosby
更新时间: 2019-08-07
摘要: Soil organic matter (SOM) is an indicator of sustainable land management as stated in the global indicator framework of the United Nations Sustainable Development Goals (SDG Indicator 15.3.1). Improved forecasting of future changes in SOM is needed to support the development of more sustainable land management under a changing climate. Current models fail to reproduce historical trends in SOM both within and during transition between ecosystems. More realistic spatio‐temporal SOM dynamics require inclusion of the recent paradigm shift from SOM recalcitrance as an “intrinsic property” to SOM persistence as an “ecosystem interaction”. We present a soil profile, or pedon‐explicit, ecosystem‐scale framework for data and models of SOM distribution and dynamics which can better represent land use transitions. Ecosystem‐scale drivers are integrated with pedon‐scale processes in two zones of influence. In the upper vegetation zone SOM is affected primarily by plant inputs (above and belowground), climate, microbial activity and physical aggregation and is prone to destabilization. In the lower mineral‐matrix zone SOM inputs from the vegetation zone are controlled primarily by mineral‐phase and chemical interactions, resulting in more favourable conditions for SOM persistence. Vegetation zone boundary conditions vary spatially at landscape scales (vegetation cover) and temporally at decadal scales (climate). Mineral‐matrix zone boundary conditions vary spatially at landscape scales (geology, topography) but change only slowly. The thicknesses of the two zones and their transport connectivity are dynamic and affected by plant cover, land use practices, climate and feedbacks from current SOM stock in each layer. Using this framework we identify several areas where greater knowledge is needed to advance the emerging paradigm of SOM dynamics ‐ improved representation of plant‐derived carbon inputs, contributions of soil biota to SOM storage and effect of dynamic soil structure on SOM storage – and how this can be combined with robust and efficient soil monitoring.

24624. 题目: The effect of exogenous organic matter on the thermal properties of tilled soils in Poland and the Czech Republic
文章编号: N19080710
期刊: Journal of Soils and Sediments
作者: Bogusław Usowicz, Jerzy Lipiec
更新时间: 2019-08-07
摘要: Purpose: Organic matter improves soil fertility and water and thermal properties, but its content often decreases. This decrease may be mitigated by the addition of exogenous organic matter (EOM). The aim of this study was to assess the effect of EOMs, including compost from manure, slurry, and straw (Ag); industrial organic compost from sewage sludge (Ra); animal meal from animal by-products (Mb); and digestate from a biogas fry factory (Dg) on soil thermal conductivity, heat capacity, thermal diffusivity, water content, and bulk density in the top (0–15-cm) layer of two soils in Poland and the Czech Republic. Materials and methods: Irrespective of EOM type, the total yearly nitrogen application rate being 200 kg N ha⁻¹ (100%) was from a given EOM at the rates 0, 50, 75, and 100% and the remaining parts from the mineral fertilizer. The study was conducted in 2013–2014 in Poland (Braszowice) and the Czech Republic (Pusté Jakartice) on loam silt and clay silt loam, respectively, as part of a cross-border cooperation project. The soil properties were examined using classical descriptive statistics, semivariograms, and kriging-interpolated maps. Results and discussion: Analysis of linear regressions (trends) showed that the EOM application rate influenced (positively or negatively) the soil properties in most measurement occasions. The variability of all soil properties was low and medium (coefficient of variation 7.3–34%). Geostatistical analysis indicated that the spatial dependence (C₀/(C₀ + C_s)) of the soil properties on the EOM-amended plots was very strong or moderate. The maps revealed that the heterogeneity and degree of patch fragmentation were greater for thermal conductivity and heat capacity than for thermal diffusivity, water content, and bulk density. In general, all the soil properties were spatially more variable in the Braszowice than Pusté Jakartice soil and in spring than autumn in both sites. Conclusions: The spatial analysis and maps enhance the comprehensive understanding of changes in soil thermal properties in response to EOM application. Suitability of the results from the field experiments in models predicting some thermal properties based on soil bulk density and water content in relation to EOM addition was indicated. Expressing the amount of EOMs added using the organic carbon content basis (% kg OC/kg of soil) instead of the nitrogen content basis allowed identifying areas on the kriging-interpolated maps where the distribution of soil thermal properties resembled that of soil organic carbon content, water content, and bulk density. Thus, the effect of EOMs on soil thermal properties is considered along with changes in soil water content and bulk density. The results will be helpful in forecasting effects of exogenous organic matter on the soil thermal properties affecting surface-energy partitioning, temperature distribution in soil, and plant growth.

24625. 题目: A consortium of fungal isolates and biochar improved the phytoremediation potential of Jacaranda mimosifolia D. Don and reduced copper, manganese, and zinc leaching
文章编号: N19080709
期刊: Journal of Soils and Sediments
作者: Christyan Paiva Farias, Gabriel Sousa Alves, Denis Coelho Oliveira, Edmar Isaías de Melo, Lucas Carvalho Basilio Azevedo
更新时间: 2019-08-07
摘要: Purpose: A consortium of fungal isolates may improve phytoremediation by stimulating root growth whereas biochar reduces metal leaching in contaminated soils. We combined these treatments to evaluate to what extent Jacaranda mimosifolia D. Don seedlings extract metals (Cu, Mn, and Zn) and reduce leaching in soil columns. Materials and methods: Contamination treatments were established by combining Cu (200 mg dm⁻³), Mn (450 mg dm⁻³), and Zn (450 mg dm⁻³). A spore suspension of five fungal isolates (Beauveria bassiana, Metarhizium anisopliae, Pochonia chlamydosporia, Purpureocillium lilacinum, and Trichoderma asperella) was sprayed on plant shoots and the soil surface. Biochar (1% m/v) was produced by the pyrolysis of wood sawdust and applied to the soil surface. Finally, control treatments were established in a completely randomized block design. Results and discussion: The consortium of fungal isolates increased shoot and root mass, improved the translocation potential of Cu (translocation factor (TF) of 0.25), Mn (TF of 2.93), and Zn (TF of 1.79) from roots to shoots, and increased the total accumulated mass of Mn and Zn in shoots and roots. Biochar applications improved Cu, Mn, and Zn translocation and increased the total accumulated mass of shoot Mn. Moreover, a combination of fungal isolates and biochar increased the translocation factor to 0.44 for Cu, 1.70 for Mn, and 1.34 for Zn relative to the treatment with J. mimosifolia in contaminated soil (CJ); increased shoot Cu concentration; and reduced total leached Cu by a factor of 22.9, Mn by 5.5, and Zn by 22.9 relative to the CJ treatment. A photochemical profile, based on chlorophyll a fluorescence, showed that Jacaranda mimosifolia was tolerant to contaminated soil and is a potential phytoremediator of Cu, Mn, and Zn. Conclusions: Overall, the consortium of fungal isolates and biochar improved the efficiency of phytoremediation by concentrating metals in plant tissue and reducing the risks of leaching.

24626. 题目: 500 days of swimmers: the chemical water quality of swimming pool waters from the beginning
文章编号: N19080708
期刊: Environmental Science and Pollution Research
作者: Rhys A. A. Carter, Sébastien Allard, Jean-Philippe Croué, Cynthia A. Joll
更新时间: 2019-08-07
摘要: Many studies of disinfection by-products (DBPs) in pools have focused on haloacetic acids, trihalomethanes, and chloramines, with less studies investigating the occurrence of other DBPs, such as haloketones, haloacetaldehydes, haloacetonitriles, halonitromethanes, and haloacetamides. Furthermore, while many studies have achieved a broadscreen analysis across several pools, fewer studies have followed the water quality of pools over time, with information regarding the production and fate of DBPs in pools over extended periods (e.g. > 1 year) being limited. This study reports the occurrence of 39 DBPs and several general water quality parameters in two newly built and filled swimming pools over 15 months, where investigations began prior to opening. DBP concentrations measured in this study were generally similar to or higher than those previously reported in chlorinated pools, with concentrations of chloroacetic acid, dichloroacetic acid, trichloroacetic acid, and chloral hydrate (trichloroacetaldehyde) in some samples being higher than previously reported maximum concentrations. Considering both pools, lower concentrations of DBPs were measured in the pool where a steady state non-purgeable organic carbon concentration was achieved, highlighting the importance of the establishment of a steady state balance of mineralisation versus addition of organic carbon to reduce precursors for DBP formation in pools. Pools were found to exhibit significantly higher estimated cytotoxicity than their filling water, which reflects the significantly higher concentrations of DBPs measured in the pools in comparison to the filling water. Chloral hydrate accounted for up to 99% the total estimated cytotoxicity and was found to be correlated to the number of pool entries, suggesting that swimmers may be a potential source of chloral hydrate precursors in pools. The presence and subsequent peak of non-purgeable organic carbon and DBPs prior to, and soon after, opening suggest that the building process and/or new pool infrastructure may have had a significant impact on the chemical water quality, particularly on DBP formation. This study includes the first quantification of bromochloroacetaldehyde, bromodichloroacetaldehyde, bromochloronitromethane, and dichloronitromethane in chlorinated swimming pools, and provides important new knowledge on the long-term trends of DBPs in pools.

24627. 题目: Organic micropollutant desorption in various water matrices - Activated carbon pore characteristics determine the reversibility of adsorption
文章编号: N19080707
期刊: Chemosphere
作者: Geert Aschermann, Corinna Schröder, Frederik Zietzschmann, Martin Jekel
更新时间: 2019-08-07
摘要: The adsorption of organic micropollutants (OMP) onto activated carbon (AC) in real waters is strongly affected by dissolved organic matter (DOM). This study examines the impact of DOM quantity and composition in terms of OMP desorption from different AC, by using four different water samples. In batch tests, an OMP concentration drop in the influent of an AC treatment system was simulated. These tests were conducted with six AC products with different internal pore structures. The tests were evaluated with respect to the extent of OMP desorption by interpreting corresponding OMP adsorption and desorption isotherms. For each tested AC and each evaluated OMP the isotherms in the different water samples were qualitatively very similar. Thus, despite different DOM composition very similar OMP desorption extents can be expected in different waters. Among the AC products a clear trend can be seen in all waters, namely that increasing pore size results in increasing desorption. The OMP desorption extent was quantified by a simple Freundlich equation-based approach, expressing the relative position of corresponding adsorption and desorption isotherms via the ratio K_{F, Des}/K_{F, Ads}. Plotting K_{F, Des}/K_{F, Ads} of any given substance for the different tested AC in one water over the average AC pore size shows a linear correlation. This confirms that the OMP desorption extent in real waters is strongly impacted by the AC pore structure. Furthermore, it indicates that the average AC pore size might be a good tool to assess the vulnerability of treatment systems towards desorption.

24628. 题目: DRIFTS peaks as measured pool size proxy to reduce parameter uncertainty of soil organic matter models
文章编号: N19080706
期刊: Biogeosciences
作者: Moritz Laub, Michael Scott Demyan, Yvonne Funkuin Nkwain, Sergey Blagodatsky, Thomas Kätterer, Hans-Peter Piepho, and Georg Cadisch
更新时间: 2019-08-07
摘要: The initialization of soil organic matter (SOM) turnover models has been a challenge for decades. Instead of using laborious and error prone size-density fractionation SOM pool partitioning, we propose the inexpensive, rapid, and non destructive Diffuse reflectance mid infrared Fourier transform spectroscopy (DRIFTS) technique on bulk soil samples to gain information on SOM pool partitioning from the spectra. Specifically, the DRIFTS stability index, defined as the ratio of aliphatic C-H (2930 cm⁻¹) to aromatic C=C (1620 cm⁻¹) stretching vibrations, was used to divide SOM into fast and slow cycling pools in the soil organic module of the DAISY model. Long-term bare fallow plots from Bad Lauchstädt (Chernozem, 25 years) and the Ultuna frame trial in Sweden (Cambisol, 50 years) were combined with bare fallow plots of 7 years duration in the Kraichgau and Swabian Jura region in Southwest Germany (Luvisols). All fields had been in agricultural use for centuries before fallow establishment, so classical theory would suggest an initial steady state of SOM, which was hence used to compare the performance of DAISY initializations against the newly established DRIFTS stability index. The test was done using two different published parameter sets (2.7 × 10⁻⁶ d⁻¹, 1.4 × 10⁻⁴ d⁻¹, 0.1 compared to 4.3 × 10⁻⁵ d⁻¹, 1.4 × 10⁻⁴ d⁻¹, 0.3 for the turnover rates of slow pool, fast pool and humification efficiency, respectively). The DRIFTS initialization of SOM pools significantly reduced model errors of poor performing model runs assuming steady state, irrespective of the turnover rates used, but the faster turnover parameter set fit better to all sites except Bad Lauchstädt. This suggests that soils under long-term agricultural use were not necessarily at steady state. A Bayesian calibration was applied in a next step to identify the best-fitting turnover rates for the DRIFTS stability index in DAISY, both for each site individually and for a combination of all sites. The two approaches which significantly reduced parameter uncertainty and equifinality were: (1) the addition of the physico-chemically based DRIFTS stability index, and (2) combining several sites into one Bayesian calibration, as derived turnover rates can be strongly site specific. The combination of all four sites showed that SOM is likely lost at relatively fast turnover rates with the 95 % credibility intervals of the slow SOM pools half life ranging from 278 to 1095 years, with 426 years as a value of highest probability density. The credibility intervals of this study were consistent with several recently published Bayesian calibrations of similar SOM models, all turnover rates were considerably faster than earlier models suggested. It is therefore likely that published turnover rates understimate the potential loss of SOM.

24629. 题目: Oxidation of Microcystic-LR via the solar/chlorine process: Radical mechanism, pathways and toxicity assessment
文章编号: N19080705
期刊: Ecotoxicology and Environmental Safety
作者: Julong Sun, Lingjun Bu, Shiyang Chen, Xianlei Lu, Yangtao Wu, Zhou Shi, Shiqing Zhou
更新时间: 2019-08-07
摘要: Microcystin-LR (MC-LR) is the most widely distributed and harmful variant toxins released by cyanobacteria, which poses potential threaten to people and aquatic animals when entering natural water. In our research, solar/chlorine process was comprehensively investigated to degrade and detoxify MC-LR. Under the chlorine concentration of 1.0 mg L⁻¹, MC-LR (1.0 μM) was decreased by 96.7%, 26%, and 9% by solar/chlorine process, chlorination, and solar irradiation respectively. Quenching experiments confirmed that reactive chlorine species (RCS) and hydroxyl radical (HO) were the predominant reactive species in solar/chlorine process at neutral condition, and ozone was generated because of the participation of triplet-state oxygen (O(³P)). The respective contributions of each reactive species were calculated with the order as: RCS, HO, ozone, and solar irradiation. The presence of HCO₃⁻ and natural organic matter in water inhibited the degradation efficiency of MC-LR. Moreover, the transformation products of MC-LR generated during the solar/chlorine process were identified and a possible pathway was proposed. The hepatotoxicity of MC-LR and its transformation products was compared using protein phosphatase 2A. Our experimental results revealed that the concentration and hepatotoxicity of MC-LR both significantly decreased, and most products were not hepatoxic. Overall, the solar/chlorine process is a promising alternative technology to degrade MC-LR during eutrophication.
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24630. 题目: Enhanced biochar stabilities and adsorption properties for tetracycline by synthesizing silica-composited biochar
文章编号: N19080704
期刊: Environmental Pollution
作者: Zhendong Zhao, Tiantian Nie, Wenjun Zhou
更新时间: 2019-08-07
摘要: The silica-composited biochars (SBC) were synthesized by adding silica particulates into bamboo biomass during pyrolysis at 700 °C to examine the effect of silica addition on biochar stabilities and adsorption properties for tetracycline (TC). Silica addition increased the total pore volume and average pore diameter of biochar due to the abundant mesopores in SBC, but decreased specific surface area due to the blockage of biochar pore with silica particles. Biochar stability was obviously enhanced with silica addition due to the decreased atomic ratio of H/C and O/C, the reduced C loss amount after chemical oxidation treatment, and the increased thermal stability. The adsorption capacities of SBC for TC were greatly enhanced with silica addition and increased with the increasing silica addition amount, which can be attributed to the facilitating effect of π–π electron donor acceptor (EDA) interaction and pore-filling effect. In addition, silica addition can also effectively enhance the oxidation resistance of biochar for TC adsorption, since the decreased degree (δ) of TC adsorption amounts on the biochars after chemical oxidation decreased with the increasing silica addition level. The observed positive correlations between δ values and the corresponding C loss amount of biochars after chemical oxidation suggested that the high carbon stability was favorable for the maintenance of biochar adsorption capacity. These results can provide a new way to improve biochar stabilities, aging resistance, and adsorption properties for organic pollutants.
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24631. 题目: Porewater exchange drives trace metal, dissolved organic carbon and total dissolved nitrogen export from a temperate mangrove wetland
文章编号: N19080703
期刊: Journal of Environmental Management
作者: Mahmood Sadat-Noori, William Glamore
更新时间: 2019-08-07
摘要: Porewater exchange is usually the least quantified process in delivering dissolved material from wetlands to coastal waters, although it has been recognised as an important pathway for the transport of trace metal, carbon and nutrient to the ocean. Here, surface water fluxes of dissolved manganese (Mn), iron (Fe), dissolved organic/inorganic carbon (DOC/DIC), total dissolved nitrogen (TDN) and phosphorous (TDP) were estimated from a temperate mangrove wetland (Kooragang Island, Newcastle, Australia). Radon (²²²Rn, a natural groundwater tracer) was used to develop a mass balance model to quantify porewater exchange rates and evaluate the contribution of porewater-derived dissolved material to the overall wetland surface water export. A 25-h time series dataset depicted a clear peak of Mn, Fe, TDN, DOC and radon during ebb tides which related to porewater discharge. Porewater exchange rates were estimated to be 14.0 ± 6.3 cm/d (0.18 ± 0.08 m³/s), mainly driven by tidal pumping, and facilitated by a large number of crab burrows at the site. Results showed that the wetland was a source of Mn, Fe, TDN and DOC to the adjacent river system and a sink for TDP and DIC. Surface water Mn, Fe, TDN and DOC exports were 4.0 ± 0.6, 6.6 ± 1.6, 23.9 ± 3.6 and 197.7 ± 29.7 mmol/m² wetland/d, respectively. Porewater-derived Mn, Fe, TDN and DOC accounted for ~95, 100, 89 and 54% of the wetland surface water exports demonstrating its significant contribution. Our study indicates that temperate mangrove wetlands can be a major source of dissolved metal, carbon and nutrient delivery to coastal waters and that mangrove porewater exchange significantly contributes to this process.
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24632. 题目: Reduction of N₂O emission by biochar and/or 3,4-dimethylpyrazole phosphate (DMPP) is closely linked to soil ammonia oxidizing bacteria and nosZI-N₂O reducer populations
文章编号: N19080702
期刊: Science of The Total Environment
作者: Hao Chen, Chang Yin, Xiaoping Fan, Mujun Ye, Hongyun Peng, Tingqiang Li, Yuhua Zhao, Steven A. Wakelin, Guixin Chu, Yongchao Liang
更新时间: 2019-08-07
摘要: Biochar has been demonstrated to reduce nitrous oxide (N₂O) emissions from soils, but its effect is highly soil-dependent. In particular, in soils with strong nitrification potential, biochar addition may increase N₂O emissions. Thus, in soils with strong nitrification potential, the combination of biochar with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) may be more effective in reducing N₂O emissions than biochar alone. However, the combined use of biochar and DMPP on soil N₂O emissions is relatively unexplored, and underlying microbial mechanisms of how biochar and/or DMPP amendment affect N₂O emissions is still largely unknown. Here, a 30-day incubation experiment was established with four treatments: CK (control), BC (biochar), DMPP, and BD (biochar and DMPP), all at agronomically recommended rates, and N cycling assessed following addition of urea. Treatment of soil with BC, DMPP and BD reduced N₂O emissions (compared with urea alone) by 59.1%, 95.5% and 74.1%, respectively. Quantification of N cycling genes (amoA, nirS, nirK, and nosZ) indicated that biochar stimulated growth of ammonia oxidizing archaea (AOA) and bacteria (AOB), while DMPP alone inhibited the activity and growth of AOB. In the BD treatment, DMPP was absorbed onto biochar reducing its efficacy in inhibiting AOB growth. The response patterns of nirS/nirK nitrite-reducing denitrifiers to biochar and/or DMPP addition varied among clades. Notably, biochar and/or DMPP increased the abundance of nosZI and nosZII-N₂O reducers, but nosZI-clade taxa were more closely associated with reducing N₂O emission than nosZII taxa. Overall, our findings proved that the dynamics of AOB and nosZI-N₂O reducers resulting from the addition of biochar and/or DMPP played a key role in governing soil N₂O emissions.
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24633. 题目: Biodegradation-induced signatures in sediment pore water dissolved organic matter: Implications from artificial sediments composed of two contrasting sources
文章编号: N19080701
期刊: Science of The Total Environment
作者: Morgane Derrien, Kyung-Hoon Shin, Jin Hur
更新时间: 2019-08-07
摘要: Biodegradation is one of the main processes causing the changes in amount, composition and properties of organic matter in sediment and water-sediment interface. The degradation processes of sediment organic matter lead to a release of dissolved organic matter (DOM) into the pore water via hydrolysis and depolymerization of particulate organic matter (POM). Whereas the pore waters represent a reactive zone in sediment closely linked to biogeochemistry of the substrate, they are still poorly characterized under diagenetic processes. In this study, we examined the DOM alterations in sediment pore water originating from the mixtures of two contrasting POM sources at known ratios through controlled incubation experiments with two different oxygen conditions (i.e., oxic versus anoxic). The changes in pore water DOM were tracked using fluorescence and absorbance spectroscopy and size exclusion chromatography. The results based on the sediments artificially mixed of two end-member sources (e.g., soil and algae) showed that the most affected parameter during the biodegradation process was the amount of the pore water DOM. It was also demonstrated that the changes in the spectroscopic and molecular properties were more dependent on the POM sources and the mixing ratios rather than on the oxygen conditions. This study provides insights into the responding features of DOM in a reactive sediment zone as pore water to the main biogeochemical process.
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24634. 题目: Interactions between Organic Model Compounds and Ion Exchange Resins
文章编号: N19080613
期刊: Environmental Science & Technology
作者: Pascal Finkbeiner, Graeme Moore, Tebogo Tseka, Thabo T. I. Nkambule, Lueta De Kock, Bruce Jefferson, Peter Jarvis
更新时间: 2019-08-06
摘要: Ion exchange (IEX) can successfully remove natural organic matter (NOM) from surface water. However, the removal mechanism is not well understood due to the complexity and variability of NOM in real source waters as well as the influence of multiple parameters on the removal behavior. For example, this includes the physicochemical properties of the NOM and IEX resin, and the presence of competing anions. Model compounds with a range of physical and chemical characteristics were therefore used to determine the mechanisms of NOM removal by IEX resins. Fifteen model compounds were selected to evaluate the influence of hydrophobicity, size, and charge of organic molecules on the removal by ion exchange, both individually and in mixtures. Three different resins, comprising polystyrene and polyacrylic resin of macroporous and gellular structure, showed that charge density (CD) was the most important characteristic that controlled the removal, with CD of >5 mequiv mgDOC–1 resulting in high removal (≥89%). Size exclusion of compounds with high MW (≥8 kDa) was evident. The hydrophobicity of the resin and model compound was particularly important for removal of neutral molecules such as resorcinol, which was best removed by the more hydrophobic polystyrene resin. Relationships were identified that provided explanations of the interactions observed between NOM and IEX resin in real waters.

24635. 题目: Persistence of dissolved organic matter explained by molecular changes during its passage through soil
文章编号: N19080612
期刊: Nature Geoscience
作者: Vanessa-Nina Roth, Markus Lange, Carsten Simon, Norbert Hertkorn, Sebastian Bucher, Timothy Goodall, Robert I. Griffiths, Perla G. Mellado-Vázquez, Liesje Mommer, Natalie J. Oram, Alexandra Weigelt, Thorsten Dittmar, Gerd Gleixner
更新时间: 2019-08-06
摘要: Dissolved organic matter affects fundamental biogeochemical processes in the soil such as nutrient cycling and organic matter storage. The current paradigm is that processing of dissolved organic matter converges to recalcitrant molecules (those that resist degradation) of low molecular mass and high molecular diversity through biotic and abiotic processes. Here we demonstrate that the molecular composition and properties of dissolved organic matter continuously change during soil passage and propose that this reflects a continual shifting of its sources. Using ultrahigh-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, we studied the molecular changes of dissolved organic matter from the soil surface to 60 cm depth in 20 temperate grassland communities in soil type Eutric Fluvisol. Applying a semi-quantitative approach, we observed that plant-derived molecules were first broken down into molecules containing a large proportion of low-molecular-mass compounds. These low-molecular-mass compounds became less abundant during soil passage, whereas larger molecules, depleted in plant-related ligno-cellulosic structures, became more abundant. These findings indicate that the small plant-derived molecules were preferentially consumed by microorganisms and transformed into larger microbial-derived molecules. This suggests that dissolved organic matter is not intrinsically recalcitrant but instead persists in soil as a result of simultaneous consumption, transformation and formation.

24636. 题目: Cobalt-impregnated biochar (Co-SCG) for heterogeneous activation of peroxymonosulfate for removal of tetracycline in water
文章编号: N19080611
期刊: Bioresource Technology
作者: Van-Truc Nguyen, Thanh-Binh Nguyen, Chiu-Wen Chen, Chang-Mao Hung, C.P. Huang, Cheng-Di Dong
更新时间: 2019-08-06
摘要: Cobalt-impregnated spent coffee ground biochar (Co-SCG) was synthesized and applied for tetracycline (TC) removal from water. The results showed that Co-SCG biochar exhibited marked adsorption capacity and catalyst activity. The maximum adsorption capacity of Co-SCG biochar toward TC was 370.37 mg g^-1. TC was almost completely degraded in 25 min with a rate constant of 17.78 x 10^-2 min^-1 under the following optimal condition: TC concentration of 0.2 mM, PMS concentration of 0.6 mM, Co-SCG dosage of 100 mg L^-1, and pH of 7.0. Co-SCG was characterized for surface properties by SEM, TEM, HRTEM, and BET. The concentration of 16 PAHs in Co-SCG biochar was studied also. Results demonstrated that Co-SCG was an effective eco-friendly material for the removal of tetracycline from water.
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24637. 题目: A sustainable ferromanganese biochar adsorbent for effective levofloxacin removal from aqueous medium
文章编号: N19080610
期刊: Chemosphere
作者: Yujia Xiang, Zhangyi Xu, Yaoyu Zhou, Yuyi Wei, Xingyu Long, Yangzhou He, Dan Zhi, Jian Yang, Lin Luo
更新时间: 2019-08-06
摘要: This present study reported the synthesis and characterization of a low-cost, environment friendly and high efficient biochar, ferromanganese modified biochar (Fe/Mn-BC) for the removal of levofloxacin (LEV) from aqueous medium. Fe/Mn-BC was synthesized through the facile co-precipitation of Fe, Mn with vinasse wastes and then pyrolysis under controlled conditions. The characterization of Fe/MnBC was analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction patterns (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman. Some influencing factors (e.g., pH, Fe/Mn-BC dosage, initial LEV concentration, ionic strength, contact time and temperature) were comprehensively investigated. The results manifested that the adsorption process of LEV onto Fe/Mn-BC was high pH dependence and the maximum adsorption capacity was achieved at pH 5. Moreover, the adsorption capacity of LEV was increased with increasing ionic strength. To gain a clearer perspective on the adsorption behavior of LEV onto Fe/Mn-BC, the adsorption kinetics and isotherms were also performed, revealing pseudo-second-order and Freundlich model had a better fitting effect. Reusability experiments indicated that Fe/Mn-BC could maintain a certain adsorption capacity for LEV after 5 recycles. Overall, this work showed that Fe/Mn-BC was an effective and promising adsorbent for eliminating LEV from aqueous medium.

24638. 题目: Effects of total organic carbon content and leaching water volume on migration behavior of polycyclic aromatic hydrocarbons in soils by column leaching tests
文章编号: N19080609
期刊: Environmental Pollution
作者: Ting Cai, Yue Ding, Zhihuan Zhang, Xinwei Wang, Tieguan Wang, Yuanyuan Ren, Yibo Dong
更新时间: 2019-08-06
摘要: The risk of soils transferring polycyclic aromatic hydrocarbons (PAHs) into groundwater has caused widespread concern. Research on the leaching behavior of PAHs in soil profiles is very important for assessing this risk. Column leaching tests were carried out to provide insight into the effect of TOC and leaching water volume on leaching behavior of PAHs. Four groups were leached intermittently by deionized water under the same leaching rate for 10 d, 30 d, 90 d and 120 d. These four leaching periods are equivalent to 1 yr, 3 yr, 9 yr and 12 yr of rainfall time under natural conditions, respectively. The results showed that residual concentrations of PAHs on the surface of soil (0–5 cm) in three columns after 30 d of leaching were 37.9 μg/g, 18.5 μg/g and 3.7 μg/g, respectively, which was consistent with their TOC contents. According to the correlation analysis, both residual concentrations of ∑₁₆PAHs and PAHs with different ring numbers were significantly correlated with the TOC content at depths of 5–100 cm after 30 d of leaching. With increased leaching water volume, PAH migration rates significantly decreased (from 3.13 μg/g/d to 0.005 μg/g/d) from 10 d to 120 d, which indicates that the initial period of the leaching process has a stronger effect on PAH vertical migration than the later stages of the process. Under long-term leaching, PAHs that were not leached previously were capable of migrating deeper into the soil profile. Therefore, it has the risk of PAH-contaminated soils transferring PAHs into groundwater.
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24639. 题目: Retention of propiconazole and terbutryn on acid sandy-loam soils with different organic matter and Cu concentrations
文章编号: N19080608
期刊: Journal of Environmental Management
作者: Manuel Conde-Cid, Vanesa Santás-Miguel, Claudia Campillo-Cora, Cristina Pérez-Novo, David Fernández-Calviño
更新时间: 2019-08-06
摘要: Equilibrium propiconazole and terbutryn adsorption characteristics were evaluated in ten acid vineyard soils with a wide range of organic matter and copper concentrations using batch experiments. Adsorption data from equilibrium adsorption experiments were generally well described by linear and Freundlich models. Parameters from these models showed that soil organic matter played a key role of propiconazole adsorption processes, but also the amorphous Fe oxides content in soils. Soil organic matter positively influenced terbutryn adsorption, whereas increases in exchangeable copper decreased terbutryn adsorption. Desorption experiments showed that both, propiconazole and terbutryn adsorption in soils was quite irreversible, i.e. the amount of pesticides desorbed after its adsorption was always less than 50%.

24640. 题目: Identifying novel treeline biomarkers in lake sediments using an untargeted screening approach
文章编号: N19080607
期刊: Science of The Total Environment
作者: Ammar Saleem, Madison A. Bell, Linda E. Kimpe, Jennifer B. Korosi, John T. Arnason, Jules M. Blais
更新时间: 2019-08-06
摘要: Paleolimnology uses sedimentary biomarkers as proxies to reconstruct long-term changes in environmental conditions from lake sediment cores. This work describes an untargeted metabolomics-based approach and uniquely applies it to the field of paleolimnology to identify novel sediment biomarkers to track long-term patterns in treeline dynamics. We identified new potential biomarkers across the Canadian northern Arctic, non-alpine, treeline using high-resolution accurate mass spectrometry, and pattern recognition analysis. This method was applied to 120 sediment core extracts from 14 boreal, 25 forest-tundra, and 21 tundra lakes to assess long-term fluctuations in treeline position. High resolution accurate mass spectrometry resolved many compounds from complex mixtures with low mass accuracy errors. This generated a large dataset that required metabolomics styled statistical analyses to identify potential biomarkers. In total, 29 potential biomarkers discriminated between boreal and tundra lakes. Tetrapyrrole-type phorbides and squalene derivatives dominated in boreal regions, while biohopane-type lipids were in the tundra regions. Tetrapyrroles were in both surface and subsurface sediments of boreal lakes indicating these compounds can survive long-term burial in sediments. At the ecozone level, tetrapyrroles were more abundant in boreal Taiga Shield, and Taiga Plains. Boreal plant extracts belonging to Pinaceae and Ericaceae also contained tetrapyrroles. Squalene derivatives demonstrated long-term preservation, but wider distribution than tetrapyrroles. Hopanoids were present in tundra and forest-tundra lake regions, specifically the Low Arctic and Taiga Shield, and were absent in all boreal lake sediments. Herein, we describe a method that can systematically identify new paleolimnological biomarkers. Novel biomarkers would facilitate multi-proxy paleolimnological studies and potentially lead to more accurate paleoenvironmental reconstructions.
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