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25721. 题目: Effect of cephalexin after heterogeneous Fenton-like pretreatment on the performance of anaerobic granular sludge and activated sludge
文章编号: N19062804
期刊: Chemosphere
作者: Chengyuan Su, Xumeng Lin, Peng Zheng, Yongshen Chen, Lijian Zhao, Yongde Liao, Jie Liu
更新时间: 2019-06-28
摘要: Effects of Fe₃O₄ NPs heterogeneous Fenton-like pretreatment on the physicochemical properties and microbial community structure of anaerobic granular sludge (AGS) and activated sludge (AS) with cephalexin were investigated. Results showed that the average removal rate of chemical oxygen demand (COD) by the AGS was 80.9%, 85.9%, 90.3% and 91.6%, respectively, at cephalexin without pretreatment, pretreatment with 20% (H₂O₂), 40% (H₂O₂) and 60% (H₂O₂). Compared to the reactor without pretreatment, the COD removal rate increased by 24.14% with 60% (H₂O₂) pretreatment for the AS. Dehydrogenase levels in the AS were 313.05, 351.12, 434.81 and 480.77 mg TF (g·h)⁻¹, which increased with higher concentrations of the pretreatment. Three-dimensional fluorescence (EEM) spectra analysis showed that the absorption peak intensities of humic acid in soluble microbial products (SMP) decreased in the AGS with increasing pretreatment. In the AGS, the dominant bacterial populations were Levilinea, Litorilinea and Clostridium sensu stricto. Clostridium sensu stricto accounting for 4.35% without pretreatment, while it was as high as 17% when it was pretreated with 60% (H₂O₂). The increase in the proportion of Clostridium sensu stricto was beneficial to the removal of organic pollutants. The pretreatment was also beneficial to the growth of acetic acid producing Methanothrix. For the AS, Gemmobacter were the dominant species, which increased from 6.56% to 32.61% after increasing the pretreatment to 40% (H₂O₂). Furthermore, the microbial capacities of amino acid metabolism and carbohydrate metabolism were enhanced by addition of pretreatment.
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25722. 题目: Effects of the arrival of fresh organic matter on eroded and nutrient-depleted trawling grounds (Gulf of Castellammare, SW Mediterranean)
文章编号: N19062803
期刊: Biogeosciences
作者: Sarah Paradis, Antonio Pusceddu, Pere Masqué, Pere Puig, Davide Moccia, Tommaso Russo, and Claudio Lo Iacono
更新时间: 2019-06-28
摘要: Bottom trawling in the deep sea is one of the main drivers of sediment resuspension, eroding the deep seafloor and altering the content and composition of sedimentary organic matter (OM). The physical and biogeochemical impacts of bottom trawling on the seafloor were studied in the continental slope of the Gulf of Castellammare, Sicily (Southwestern Mediterranean) through the analysis of two triplicate sediment cores collected in trawled and untrawled sites (~ 550 m water depth) during the summer of 2016. Geochemical and sedimentological parameters (excess ²¹⁰Pb, excess ²³⁴Th, ¹³⁷Cs, dry bulk density, and grain size), elemental (organic carbon and nitrogen) and biochemical composition of sedimentary OM (proteins, carbohydrates, lipids), as well as its freshness (phytopigments) and degradation rates were determined in both coring locations. The untrawled site had a sedimentation rate of 0.15 cm yr⁻¹ and presented a 6-cm thick surface mixed layer that contained coarser sediment with low excess ²¹⁰Pb concentrations, possibly resulting from the resuspension, posterior advection, and eventual deposition of siltier and older sediment from adjacent trawling grounds. In contrast, the trawled site was characterized by highly eroded and compacted century-old sediment, as shown by the lack of excess ²¹⁰Pb and high dry bulk densities. The continuous erosion in the trawled site has led to the depletion of OM, which were between 20 % and 60 % lower than those in the untrawled site, as well as to statistically significant differences in the biochemical composition of OM. Nevertheless, the upper 2 cm of the trawled site consisted of recently accumulated sediments, enriched in excess ²³⁴Th, excess ²¹⁰Pb, and phytopigments, which had similar OM contents to surface sediments from the untrawled core. The arrival of fresh sediment in a chronically-trawled deep-sea site that is generally deprived of OM was associated with an enhancement of remineralization rates, reflected by protein turnover rates of 0.025 d⁻¹, which doubled the rates quantified in surface sediments of the untrawled site. We conclude that the detrimental effects of bottom trawling can be temporarily and partially abated by the arrival of fresh and nutritionally-rich OM, which stimulate the response of benthic communities. However, these ephemeral deposits are likely to be swiftly eroded due to the high trawling frequency over fishing grounds, highlighting the importance of establishing management strategies to mitigate the impacts of bottom trawling.

25723. 题目: Soil organic carbon recovery in tropical tree plantations may depend on restoration of soil microbial composition and function
文章编号: N19062802
期刊: Geoderma
作者: Mark T.L. Bonner, John Herbohn, Nestor Gregorio, Arturo Pasa, Mayet S. Avela, Crisanto Solano, Maria Opelia Maranguit Moreno, Angela Almendras-Ferraren, Jarrah Wills, Luke P. Shoo, Susanne Schmidt
更新时间: 2019-06-28
摘要: Soil organic carbon (SOC) supports essential functions in terrestrial biomes and global biogeochemical cycles, and tropical tree plantations are often called upon to reverse deforestation-induced SOC loss. Yet the comparative efficacy of different plantation types and associated drivers of SOC restoration remain unclear. Theory suggests that higher chemical and spatial heterogeneity of plant litter should promote greater efficiency of soil microbial communities involved in SOC formation, so we hypothesised that more species-diverse tree plantations should be more effective in accelerating recovery of SOC. To test this, we compared developmental recovery of SOC and soil microbial communities between monoculture (Swietenia macrophylla King, mahogany) and highly diverse and mostly native species plantations (termed “rainforestation”). All plantation types, which were aged 15 to 20 years, only restored the composition of the soil microbial community to 20–30% of the reference, selectively logged old-growth rainforest. Contrary to our hypothesis, mahogany plantations, but not rainforestation, restored SOC and microbial function. Rainforestation shifted soil microbial composition and the composition of the understory vegetation closer to reference conditions. Soil microbial composition at all plantation sites was correlated with plant composition and functional traits, and better explained variation in SOC than land use. In particular, soil fungal PLFA biomass displayed a strong positive correlation with topsoil SOC concentration. This suggests that belowground restoration with tropical reforestation is slow relative to typical rotation times of tropical plantations (15–20 years). We conclude that reliable and rapid restoration of SOC may depend on interventions both above and below ground to re-instate the soil microbial community. This may require careful selection of plant species in combination with microbial inoculations.

25724. 题目: Multivariate analysis of biochar-derived carbonaceous nanomaterials for detection of heavy metal ions in aqueous systems
文章编号: N19062801
期刊: Science of The Total Environment
作者: J. Plácido, S. Bustamante López, K.E. Meissner, D.E. Kelly, S.L. Kelly
更新时间: 2019-06-28
摘要: This article focuses on implementing multivariate analysis to evaluate biochar-derived carbonaceous nanomaterials (BCN) from three different feedstocks for the detection and differentiation of heavy metal ions in aqueous systems. The BCN were produced from dairy manure, rice straw and sorghum straw biochar using our NanoRefinery process. The NanoRefinery process transforms biochar into advanced nanomaterials using depolymerisation/chemical oxidation and purification of nanomaterials using solvent extraction. Dairy manure biochar-derived carbonaceous nanomaterials (DMB-CN), rice straw biochar-derived carbonaceous nanomaterials (RSB-CN) and sorghum straw biochar-derived carbonaceous nanomaterials (SSB-CN) were utilised as probes for the evaluation of their fluorescent properties and the detection of heavy metal ions. The BCN fluorescence quenching and fluorescence recovery was tested with lead (Pb²⁺), nickel (Ni²⁺), copper (Cu²⁺) and mercury (Hg²⁺). Principal component analysis (PCA) and discriminant analysis were used to differentiate among heavy metal ions in water samples. The BCN from different feedstocks had different characteristics and produced different interactions with heavy metal ions. DMB-CN had the highest quenching for Hg²⁺ and Ni²⁺ while SSB-CN and RSB-CN responded best to Cu²⁺ and Pb²⁺, respectively. The fluorescence quenching was modelled using linear and empirical functions. PCA and discriminant analysis used the quenching measurements to differentiate heavy metal ions in aqueous system. A key result was that the discriminant analysis had a 100% accuracy to detect Pb²⁺, 66% for Ni²⁺ and Cu²⁺, and 33% for Hg²⁺. This study has shown that biochar-derived carbonaceous nanomaterials could be used in heavy metal ions sensing applications. This is the first step in the development of a fast and accurate method for the detection of heavy metal ions in waters using environmentally friendly BCN.
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25725. 题目: Assessing the chemistry and bioavailability of dissolved organic matter from glaciers and rock glaciers
文章编号: N19062715
期刊: Journal of Geophysical Research: Biogeosciences
作者: Timothy Fegel, Claudia M. Boot, Corey D. Broeckling, Jill S. Baron, Ed K. Hall
更新时间: 2019-06-27
摘要: As glaciers thaw in response to warming, they release dissolved organic matter (DOM) to alpine lakes and streams. The United States contains an abundance of both alpine glaciers and rock glaciers. Differences in DOM composition and bioavailability between glacier types, like rock and ice glaciers, remain undefined. To assess differences in glacier and rock glacier DOM we evaluated bioavailability and molecular composition of DOM from four alpine catchments each with a glacier and a rock glacier at their headwaters. We assessed bioavailability of DOM by incubating each DOM source with a common microbial community and evaluated chemical characteristics of DOM before and after incubation using untargeted gas chromatography mass spectrometry based metabolomics (GC‐MS). Prior to incubations, ice glacier and rock glacier DOM had similar C:N ratios and chemical diversity, but differences in DOM composition. Incubations with a common microbial community showed DOM from ice glacier meltwaters contained a higher proportion of bioavailable DOM (BDOM) and resulted in greater bacterial growth efficiency (BGE). After incubation, DOM composition from each source was statistically indistinguishable. This study provides an example of how MS based metabolomics can be used to assess effects of DOM composition on differences in bioavailability of DOM. Furthermore, it illustrates the importance of microbial metabolism in structuring composition of DOM. Even though rock glaciers had significantly less BDOM than ice glaciers, both glacial types still have potential to be important sources of BDOM to alpine headwaters over the coming decades.

25726. 题目: Atmospheric wet deposition of dissolved organic carbon to a typical anthropogenic-influenced semi-enclosed bay in the western Yellow Sea, China: Flux, sources and potential ecological environmental effects
文章编号: N19062714
期刊: Ecotoxicology and Environmental Safety
作者: Jianwei Xing, Jinming Song, Huamao Yuan, Xuegang Li, Ning Li, Liqin Duan, Di Qi
更新时间: 2019-06-27
摘要: Dissolved Organic Carbon (DOC) is a key organic compound in wet precipitation, but few data are available in China marginal seas. To probe the concentration, deposition flux, seasonality, source and potential ecological environmental effects of precipitation DOC, in this study, one-year precipitation samples were collected at Jiaozhou Bay (JZB), a typical anthropogenic-influenced semi-enclosed bay in the western Yellow Sea for the first time from June 2015 to May 2016. The concentrations of DOC in precipitation were highly variable with a volume-weighted mean (VWM) concentration of 3.63 mg C L⁻¹, which was mostly higher than those in other areas. DOC concentrations were lower in wet season than that in dry season due to the dilution from more amount of rainfall. The wet deposition flux of DOC was calculated to be 3.15 g C m⁻² yr⁻¹ with 68.7% of which occurred in wet season mainly owing to the promoting of more rainfall amount. Besides, local emissions together with the long-range transport of pollutants were other factors controlling precipitation DOC. Fossil fuel combustion particularly coal burning was considered to be the leading source of precipitation DOC based on correlation analysis with some generally accepted indicators. Wet deposition dominates the external input of DOC at JZB by comparison with riverine input with a percentage of 54%. Heavy storm may exert enrichment effect on DOC levels in the surface water of JZB, and then promote the secondary productivity. This study emphasizes that wet deposition is an important process that should be seriously considered in the models of global/regional carbon biogeochemical cycling.

25727. 题目: Salinity disturbance affects faunal community composition and organic matter on a restored Crassostrea virginica oyster reef
文章编号: N19062713
期刊: Estuarine, Coastal and Shelf Science
作者: Danielle Aguilar Marshall, Benoit Lebreton, Terence Palmer, Kevin De Santiago, Jennifer Beseres Pollack
更新时间: 2019-06-27
摘要: Ecological restoration has become a widely recognized tool to ameliorate the effects of habitat loss. Half Moon Reef, once a highly-productive 2 km² Crassostrea virginica oyster reef in Matagorda Bay, Texas, was harvested to depletion in the early 20th century. In 2014, a 0.23 km² reef complex was created using limestone and concrete substrates to restore oyster populations—one of the largest contiguous oyster reef restoration efforts in the U.S. In the three years post-construction, two large freshwater inflow events provided a unique opportunity to determine the effects of prolonged salinity reductions (<10) on oyster reef faunal community composition and organic matter quality. Oyster size generally increased over the 3-year study period, enhancing habitat provision for reef fauna. Reef-resident and reef-associated species metrics (abundance, biomass, diversity, and species richness) were positively correlated with salinity. Following a large salinity reduction (from ∼26 to ∼9) one year post-construction, the reef-resident faunal community shifted from dominance by small gastropods to larger and more resilient crustaceans. A second, lower magnitude salinity reduction two years post-construction did not elicit the same biotic response. Reef-associated fauna showed no patterns related to distance from the reef (13 m vs. 150 m), indicating limited influence of the restored oyster reef on fauna outside of the physical reef structure. Salinity decreases were associated with ¹³C-depletion of suspended particulate organic matter, whereas no change in isotopic composition was observed for surface sediment organic matter. Carbon/chlorophyll a and carbon/nitrogen ratios of suspended particulate organic matter indicate the quality of organic matter was higher following low salinity events, likely due to increased autochthonous production facilitated by pulses of freshwater inflow. Oysters assimilated nearly equal proportions of surface sediment organic matter and suspended particulate organic matter. It is important to understand the effects of salinity variability for the effective management of coastal restoration projects because freshwater inflow has a major influence on coastal ecosystems.
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25728. 题目: Relation between changes in organic matter structure of poultry litter and heavy metals solubility during composting
文章编号: N19062712
期刊: Journal of Environmental Management
作者: Camila da Costa Barros de Souza, Nelson Moura Brasil do Amaral Sobrinho, Erica Souto Abreu Lima, Jéssica de Oliveira Lima, Margarida Goréte Ferreira do Carmo, Andrés Calderín García
更新时间: 2019-06-27
摘要: Poultry litter (PL) is widely used as fertilizer because of its rich N, P and Ca content. When PL is applied to previously untreated soil, it is a potential contaminant. Composting is an alternative for stabilizing organic and mineral components. This study aimed to elucidate the structural changes and its influence on the solubility of heavy metals in poultry litter during the first 30 d of composting, which is the period when the most intense transformations occur. For this analysis, the transformation dynamics of the organic structures and the availability of mineral elements were studied via spectroscopic characterization, total heavy metal content determination and chemical fractionation at three composting times (0, 15, and 30 d). During composting, the material's aromaticity increased, while its aliphaticity decreased, and the hydrophobicity index increased as the polarity decreased. These results indicate that during the first 30 d, PL composting occurs via transformation of the most labile structures (carbohydrate, peptide and fatty acid fragments), thereby preserving the most stable and least functionalized structures. Composting increased the concentrations of Cu, Cr, Pb and Zn and the transformation of C_Alk-O and C_Alk-di-O associated with peptides and carbohydrates and favored solubilizing and leaching a water-soluble fraction rich in these compounds. The labile fractions of Fe and the humified organic matter fractions of Cu, Fe, Mn, Zn, and Al increased. The structural changes reduced heavy metal solubility, thus indicating that after 30 d of composting, the heavy metal contamination risk is low.

25729. 题目: Biodegradation of aged polycyclic aromatic hydrocarbons in agricultural soil by Paracoccus sp. LXC combined with humic acid and spent mushroom substrate
文章编号: N19062711
期刊: Journal of Hazardous Materials
作者: Xiuchu Liu, Wei Ge, Xiaomei Zhang, Chao Chai, Juan Wu, Dan Xiang, Xiaoyu Chen
更新时间: 2019-06-27
摘要: Paracoccus sp. LXC combined with humic acid (HA) and spent mushroom substrate (SMS) obtained from Auricularia auricular and Sarcomyxa edulis was tested for the remediation of agricultural soil contaminated with aged polycyclic aromatic hydrocarbons (PAHs). The biomass and diversity of bacteria and fungi and the soil enzyme activity were analyzed. PAH removal and dissipation kinetics were examined. The highest degradation rate of PAHs was 56.5% when soil was amended with Paracoccus sp. LXC combined with HA and unsterilized SMS from A. auricular. The half-life of PAHs decreased from 2323.3 days in natural attenuation to 66.6–277.2 days in amended treatments. Soil treated with Paracoccus sp. LXC combined with HA and SMS from A. auricular acquired high contents of organic matter and nutrients. HA and SMS aided the growth of PAH-degrading bacteria and promoted the diversity of bacteria but not of fungi. The degradation rate of PAHs was mainly correlated positively with soil laccase activity. Low- and middle-molecular-weight PAHs were significantly removed by Paracoccus sp. LXC, HA and SMS. High-molecular-weight PAHs were removed by SMS but not by Paracoccus sp. LXC. Biodegradation by Paracoccus sp. LXC combined with HA and SMS is a promising choice for remediating aged PAH-contaminated agricultural soils.

25730. 题目: Soil properties and combustion temperature: Controls on the decomposition rate of pyrogenic organic matter
文章编号: N19062710
期刊: CATENA
作者: R.B. Abney, L. Jin, A.A. Berhe
更新时间: 2019-06-27
摘要: Pyrogenic carbon (PyC) is the material left behind after incomplete combustion of biomass, including a spectrum of materials ranging from charcoal to lightly charred biomass. We investigated the roles of combustion temperature and properties of soil at two distinct landform positions on carbon dioxide (CO₂) flux from soil and decomposition of PyC. Bark from Pinus jeffreyi was charred at three temperatures (200 °C, 350 °C, and 500 °C) for an hour to create PyC before it was incubated with soil collected from eroding and depositional landform positions along the same hillslope. We determined the fraction of PyC in soil C at the beginning and end of the incubation using the Kurth-MacKenzie-Deluca digestion method. We found rates of microbial respiration in soil from the depositional landform position were over three times higher than from soil from the eroding landform position. The soil from the eroding landform position had less optimal decomposition conditions, including water holding capacity and organic matter content, compared with the soil from the depositional landform position. Furthermore, over the length of the incubation experiment, PyC concentrations decreased only in depositional soils that contained lower temperature chars, indicating that low temperature PyC has shorter residence times in soils from depositional landform positions, compared to eroding ones. Using scanning electron microscopy, we also observed physical decay of the low temperature chars. Previous research has shown that PyC is preferentially eroded from hillslopes post-fire. Here we show that erosion of PyC and deposition into depositional landform positions can cause the decay rate of PyC to significantly increase, exerting a significant control on the long-term fate of PyC in the soil system.

25731. 题目: Rice straw biochar and phosphorus inputs have more positive effects on the yield and nutrient uptake of Lolium multiflorum than arbuscular mycorrhizal fungi in acidic Cd-contaminated soils
文章编号: N19062709
期刊: Chemosphere
作者: Mohan Liu, Yeye Che, Leqi Wang, Zhuojun Zhao, Yanchao Zhang, Lingling Wei, Yan Xiao
更新时间: 2019-06-27
摘要: The purpose of the study was to examine biochar amendment, phosphorus (P) fertilizer and arbuscular mycorrhizal fungi (AMF) on the yield, nutrient and cadmium (Cd) absorption of Lolium multiflorum in acidic soil. It was shown that mycorrhizal inoculation had no positive influence on the plant shoot biomass and the contents of nitrogen (N), P, potassium (K), calcium (Ca) and magnesium (Mg) in plants at all biochar and P level treatments. Irrespective of mycorrhizal inoculation and P level, biochar amendments markedly elevated the soil available P and K uptake in plant tissues. In contrast, biochar significantly decreased the translocation factor of plants, soil exchangeable Cd, and acid and neutral phosphatase activities, regardless of the mycorrhizal inoculation and P fertilizer. Without P fertilization, biochar amendments significantly promoted shoot P content, while biochar amendments significantly reduced shoot P content when P fertilizer was applied. Without biochar application, P fertilizer application significantly promoted the biomass and N uptake of shoots in both AMF inoculation treatments, while P fertilizer increased these only in the presence of biochar and mycorrhizal inoculation. The increased N content induced by the biochar amendment elevated the shoot N:P ratio and alleviated the N deficiency with P fertilizer input. Thus, we concluded that the addition of biochar and P fertilizer showed more positive effects on the promotion of growth and nutrient uptake of L. multiflorum than AMF grown in acidic Cd-contaminated soils.
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25732. 题目: Adsorption/desorption and transport of sulfadiazine, sulfachloropyridazine, and sulfamethazine, in acid agricultural soils
文章编号: N19062708
期刊: Chemosphere
作者: M. Conde-Cid, D. Fernández-Calviño, M.J. Fernández-Sanjurjo, A. Núñez-Delgado, E. Álvarez-Rodríguez, M. Arias-Estévez
更新时间: 2019-06-27
摘要: Batch-type experiments were used to study adsorption-desorption of three sulfonamides: sulfadiazine (SDZ) sulfachloropyridazine (SCP), and sulfamethazine (SMT), in five crop soils, whereas laboratory soil column experiments were employed to obtain data on transport processes. Adsorption results were satisfactorily adjusted to Linear and Feundlich equations, with R² values above 0.95. Adsorption followed the sequence SDZ < SMT < SCP, showing higher values for soils with higher levels of organic carbon (OC) content. Conversely, desorption was higher in soils with less OC, and lower in soils with higher OC contents. The temporal moment analysis method gave values for the transport parameters τ and R which were significantly correlated with soil parameters related to organic matter, specifically OC and N concentrations. The higher retention of the three sulfonamides in soils with high organic matter content is a relevant fact, with value when programming management practices in agricultural soils, and specifically in relation to the spreading of animal manures, slurries, or waste containing these emerging pollutants.

25733. 题目: Green preparation of magnetic biochar for the effective accumulation of Pb(II): Performance and mechanism
文章编号: N19062707
期刊: Chemical Engineering Journal
作者: Yueling Zhao, Ruyu Zhang, Haibo Liu, Mengxue Li, Tianhu Chen, Dong Chen, Xuehua Zou, Ray L. Frost
更新时间: 2019-06-27
摘要: Magnetic biochar (MBC) was prepared by the pyrolysis of wheat straw and natural hematite in nitrogen. The effect of the pyrolysis temperature and time was considered. The as-prepared MBCs were characterized by using XRD, FTIR, BET, XPS, and a magnetic susceptibility device. The performance of the prepared MBCs on the removal of Pb(II) was evaluated. The effect of the contact time, pH value, and initial Pb(II) concentration on the adsorption capacity of Pb(II) by the MBCs was investigated. The results show that porous MBCs were successfully prepared by the pyrolysis method. The pyrolysis temperature and time controlled the pore structure, surface area, valence state of iron and magnetic susceptibility of the prepared MBCs. The prepared MBC800-120 exhibited the best Pb(II) adsorption capacity (196.91 mg/g). Moreover, the former still displayed excellent solid-liquid separation efficiency by magnetic separation due to strong magnetism. The hydrolysis-induced precipitation of PbOHCl and the surface complexation by the active sites on the surface of biochar and corroded iron were proposed as the main removal mechanisms. The experimental results provide a novel method for preparing magnetic carbon material and enhancing the comprehensive utilization of biomass and hematite.
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25734. 题目: Patterns of heavy metal immobilization by MSW during the landfill process
文章编号: N19062706
期刊: Chemical Engineering Journal
作者: Jun Yao, Qingna Kong, Zhanhong Qiu, Luxi Chen, Dongsheng Shen
更新时间: 2019-06-27
摘要: Simulated landfill was established and operated for 507 days to explore the pattern of heavy metal immobilization by municipal solid waste (MSW) in the landfill process. The results showed that 45.6 mg of Cu, 3.16 mg of Pb, and 44.2 mg of Zn were immobilized by 25 kg of MSW during the whole landfill process. The immobilization of Cu, Pb and Zn followed different patterns. Two peaks were found for the immobilization of Cu in the landfill process, which occurred at the initial stage and the acidification stage. The immobilization of Cu by MSW was more affected by the feed concentration than pH, and physical adsorption may control the immobilization. One peak was observed for the immobilization of Pb, which occurred at the initial stage of the landfill. The fluctuation of Pb concentration was similar to that of Cu. However, the immobilization of Pb was restricted due to the low feed concentration. No immobilization of Zn was observed at the initial stage of the landfill. The peak immobilization was observed from days 44 to 143 and at the acidification stage. Compared with Cu and Pb, the immobilization of Zn was more affected by pH, which might be due to their different speciation in the leachate, resulting from different affinities to dissolved organic matter. These results help to understand the migration of heavy metals in a landfill, which could provide insights for heavy metal pollution control in the landfill.
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25735. 题目: Short-term leachability of salts from Atriplex-derived biochars
文章编号: N19062705
期刊: Science of The Total Environment
作者: Kwabena Addae Sarpong, Ali Amiri, Sterling Ellis, Omololu John Idowu, Catherine E. Brewer
更新时间: 2019-06-27
摘要: Disposal of concentrate from brackish water desalination is limited by concerns of salt leaching into fresh water sources. Prevention of salt from leaching can greatly increase desalination concentrate management costs, as there are few options to recover those costs. An option for concentrate disposal is to grow halophyte crops using the concentrate as irrigation water. The purpose of this study was to determine how much of the Ca, Mg, Na, and K taken up by Atriplex species during growth can be stabilized by pyrolysis, thus preventing those cations from returning into the soil solution after harvest. Results show that salts in the biomass are concentrated into the biochars and that pyrolysis conditions affect the amount of salt that can be leached with water. Ca was the most retained of the cations: 100% and 94% were retained in A. canescens biochars and A. lentiformis 600 °C biochar, respectively. Mg retention was similar: 100% and 93% retained for A. canescens and A. lentiformis 600 °C biochars, respectively. Increasing pyrolysis temperature increased the retention of Ca and Mg; trends for K and Na were inconsistent. Soil application of these biochars will still be problematic due to low retention of Na against short-term leaching, thus limiting the potential for on-site sequestration to enable land utilization for crop production. With more understanding of the salt formation and retention mechanisms within biomass, higher amounts of salt might be sequestered longer, while taking advantage of the carbon sequestration and soil quality benefits of biochars.
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25736. 题目: Biochar and earthworms working in tandem: Research opportunities for soil bioremediation
文章编号: N19062704
期刊: Science of The Total Environment
作者: Juan C. Sanchez-Hernandez, Kyoung S. Ro, Francisco J. Díaz
更新时间: 2019-06-27
摘要: Intensive use of agrochemicals is considered one of the major threats for soil quality. In an attempt to mitigate their side-effects on non-target organisms and soil functioning, many engineering and biological remediation methodologies are currently available. Among them, the use of biochar, a carbonaceous material produced from pyrolysing biomass, represents an attractive option enhancing both remediation and soil carbon storage potentials. Currently, activation of biochar with chemical or physical agents seeks for improving its remediation potential, but most of them have some undesirable drawbacks such as high costs and generation of chemical wastes. Alternatively, the use of biological procedures to activate biochar with extracellular enzymes is gaining acceptance mainly due to its eco-friendly nature and cost-effectiveness. In these strategies, microorganisms play a key role as a source of extracellular enzymes, which are retained on the biochar surface. Recently, several studies point out that soil macrofauna (earthworms) may act as a biological vector facilitating the adsorption of enzymes on biochar. This paper briefly introduces current biochar bioactivation methodologies and the mechanisms underlying the coating of biochar with enzymes. We then propose a new conceptual model using earthworms to activate biochar with extracellular enzymes. This new earthworm-biochar model can be used as a theoretical framework to produce a new product “vermichar”, vermicompost produced from blended feedstock, earthworms, and biochar that can be used to improve soil quality and remove soil contaminants. This model can also be used to develop innovative in-situ “vermiremediation” technologies utilizing the beneficial effects of both earthworms and biochar. Since biochar may contain toxic chemicals generated during its production stages or later concentrated when applied to polluted soils, this paper also highlights the need for an ecotoxicological knowledge around earthworm-biochar interaction, promoting further discussion on suitable procedures for assessing the environmental risk of this conceptual model application in soil bioremediation.

25737. 题目: Faceted TiO₂ photocatalytic degradation of anthraquinone in aquatic solution under solar irradiation
文章编号: N19062703
期刊: Science of The Total Environment
作者: Tingming Ye, Weixiao Qi, Xiaoqiang An, Huijuan Liu, Jiuhui Qu
更新时间: 2019-06-27
摘要: Anthraquinone (AQ), a common oxygenated polycyclic aromatic hydrocarbon (PAH) in the water environment, often occurs with higher concentrations than its parent anthracene as it is the dominant intermediate from anthracene during both wastewater treatment and transformation in natural waters. During the elimination of PAHs and their intermediates, the water matrix often induces positive or negative effects. In this paper, photocatalytic degradation of AQ in the presence of inorganic ions (NO₃⁻, HCO₃⁻, Fe³⁺) and organic matter (humic acid) was studied with {101} and {010}-TiO₂ as sunlight-driven photocatalysts. Meanwhile, the effect of dissolved oxygen (DO) on photocatalytic degradation of AQ was evaluated. The results showed that NO₃⁻ had a slight suppressing effect, while HCO₃^– and Fe³⁺ promoted the photocatalytic activity due to formation of new oxidizers (CO₃⁻ and H₂O₂). Interestingly, HA could envelope {101}-TiO₂ to inhibit photodegradation; however, it had almost no effect on {010}-TiO₂ due to the different surface structures and properties. High dissolved oxygen content in water could markedly promote the photodegradation of AQ. This was consistent with the results of scavenging experiments, which demonstrated that O₂^– and h⁺ played more important roles than OH did. A small amount of benzene was detected as an intermediate product of AQ by LC-QTOF-MS analysis. Hopefully, this work can contribute to the understanding of the potential of water remediation by faceted photocatalysts.
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25738. 题目: Variation in quantity and chemical composition of soil dissolved organic matter in a peri-urban critical zone observatory watershed in Eastern China
文章编号: N19062702
期刊: Science of The Total Environment
作者: Jianfeng Tang, Wendong Wang, Lei Yang, Changli Cao, Xinhu Li
更新时间: 2019-06-27
摘要: Soil organic matter plays a fundamental role in terrestrial ecosystems. However, little is known about the spectral characteristics and fluorescent components of soil dissolved organic matter (DOM) in peri-urban ecosystems and their influencing factors. In this study, we used the fluorescence excitation-emission matrix and parallel factor analysis (EEM-PARAFAC) to characterize soil DOM in a peri-urban Critical Zone Observatory watershed in Eastern China. Soil samples were collected at depths of 0–10 cm, 10–20 cm, and 20–40 cm from 82 sites (29 forest, 11 orchard, and 42 cropland). The results showed that soil organic carbon and water-soluble organic carbon content varied with land use type, and both were significantly higher in forest than cropland and orchard samples. Three fluorescent components, humic-, fulfic-, and protein-like substances, were derived from soil DOM using the PARAFAC model. All these components were distributed differently in the three land use types, as were their UV and fluorescence indices. The spatial distribution of soil DOM showed that the quantity and chemical composition of DOM were affected by environmental variables and human disturbance, among which pH and altitude significantly affected DOM content. Anthropogenic parameters such as distance to road and distance to town strongly influenced the chemical composition and characteristics of soil DOM. Negative correlations were observed between humic-like substances and distance to road or town, while positive correlations were observed between protein-like substances and these two parameters. These results demonstrate the pronounced influence of human activities on DOM composition and characteristics in the watershed area. The findings highlight the value of soil DOM characterization to better understand the origin, composition, and fate of DOM in soils in peri-urban critical zones.
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25739. 题目: Diffusion and phosphorus solubility of biochar-based fertilizer: Visualization, chemical assessment and availability to plants
文章编号: N19062701
期刊: Soil and Tillage Research
作者: José Ferreira Lustosa Filho, Cristiane Francisca Barbosa, Jefferson Santana da Silva Carneiro, Leônidas Carrijo Azevedo Melo
更新时间: 2019-06-27
摘要: Developing slow-release phosphate sources more synchronized with the crop cycle is needed to increase phosphorus (P) use efficiency in weathered tropical soils. We hypothesized that impregnation of biomass with phosphate and magnesium prior to biochar production will generate slow-release P fertilizer and increase P use efficiency by plants. In this study, triple superphosphate (TSP) or phosphoric acid (H₃PO₄) were mixed with magnesium oxide (MgO) and poultry litter (PL) to produce slow-release P biochar-based fertilizers (BBFs). The P fractions of the BBFs soluble in water, citric acid and neutral ammonium citrate + water were analyzed. Phosphorus diffusion in soil was determined using a visualization technique over time and chemical analyses, and the agronomic efficiency of the BBFs was compared with soluble fertilizer (TSP) in both granular and powder form for maize grown in an Oxisol under greenhouse conditions. Results showed that BBFs strongly decreased water-soluble P, which caused a slow-release of P in soil as demonstrated by diffusion visualization technique. When applied as powder mixed through the soil, BBFs improved soil pH and Mg and were able to provide P to plants similarly to TSP. The granular form of PLB-H₃PO₄-MgO was equivalent to TSP for P release during early growth of maize and preserved higher amounts of P in the granule, which can be used for plants in future harvests. Pyrolysis of biomass with phosphate and magnesium can be an option to enhance P use efficiency from fertilizers, especially for on high P-fixing soils.
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25740. 题目: The influence of the quantity and quality of sediment organic matter on the potential mobility and toxicity of trace elements in bottom sediment
文章编号: N19062612
期刊: Environmental Geochemistry and Health
作者: Agnieszka Baran, Monika Mierzwa-Hersztek, Krzysztof Gondek, Marek Tarnawski, Magdalena Szara, Olga Gorczyca, Tomasz Koniarz
更新时间: 2019-06-26
摘要: Knowledge on the fraction of trace elements in the bottom sediments is a key to understand their mobility and ecotoxicological impact. The purpose of this study was to assess the influence of the content of organic matter fractions on the mobility and ecotoxicity of trace elements in sediments from the Rybnik reservoir. The most refractory fraction of organic matter—Cnh (non-hydrolysing carbon)—dominated in the sediments. The content of organic matter fractions are arranged in the following order: Cnh (non-hydrolysing carbon) > Cfa (fulvic acid) > Cha (humic acid) > DOC (dissolved organic carbon). On the other hand, the highest value of correlation coefficients was found for different fractions of trace elements and DOC content in the bottom sediments. A higher content of TOC in the sediments significantly increased the share of elements in the potential mobile fraction and, at the same time, decreased the binding of elements in the mobile fractions. Moreover, in sediments that contain more than 100 g/kg d.m. TOC, no and medium risk of trace element release from sediments was observed. The Cu, Cd and Ni were potentially the most toxic elements for biota in the Rybnik reservoir. However, the correlation between the content of trace elements and the response of bacteria was insignificant. These results suggested that the complexation of trace elements with organic matter makes them less toxic for Vibrio fischeri. The transformation and sources of organic matter play an important role in the behaviour of trace elements in the bottom sediments of the Rybnik reservoir.