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14201. 题目: Carbon-based Materials Reinforced Waste Activated Sludge Electro-dewatering for Synchronous Fuel Treatment
文章编号: N18110102
期刊: Water Research
作者: Bingdi Cao, Ruilu Wang, Weijun Zhang, Hanjun Wu, Dongsheng Wang
更新时间: 2018-11-01
摘要: Sludge treatment and disposal have become critical environmental issues in China. Electro-dewatering (ED) is an attractive technology for enhancing dewaterability and improving the sustainability of waste activated sludge (WAS) handling. However, electrically assisted mechanical dewatering processes consume more energy and the extracellular polymeric substance (EPS) dissolution caused by electrochemical reactions can lead to clogging of the filter cloth. Carbon-based materials (CBMs) such as activated carbon and graphite have electrical conductivity and well-developed pore structures which can adsorb the biopolymers. Therefore, addition of CBMs is expected to improve WAS electro-dewatering performance for fuel treatment by enhancing sludge conductivity and filterability. In this study, we evaluated the effects of the three carbon materials (AC-0, AC-5, and graphite) on sludge electro-dewatering behavior and the flammability of sludge cakes. The results showed that CBMs promote the performance of WAS electro-dewatering, and the promoting effect of the carbon materials on the sludge electro-dewatering is proportional to the electrical conductivity of the carbon material, and carbon materials can increase the electrophoretic mobility of sludge flocs and the electro-osmotic effect. Moreover, CBMs can adsorb the dissolved EPS, thus alleviate the plugging and filtration resistance of the filter medium. The addition of CBMs also decreases the energy consumption for water removal during the electro-dewatering process and improves the calorific value and sustainable combustion time of the sludge cake. Our approach can facilitate the resource utilization of the dewatered sludge cake in electro-dewatering processes.
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14202. 题目: Chlorella Vulgaris Enhance the Photodegradation of Chlortetracycline in Aqueous Solution via Extracellular Organic Matters (EOMs): Role of Triplet State EOMs
文章编号: N18110101
期刊: Water Research
作者: Yajun Tian, Jinru Zou, Li Feng, Liqiu Zhang, Yongze Liu
更新时间: 2018-11-01
摘要: Algae, which are ubiquitous in surface waters (e.g., lakes, ponds, wetlands) may play an important role in sunlight-driven transformation of compounds. This study is to investigate the role of algae (Chlorella Vulgaris) in chlortetracycline (CTC) photolysis and explore the photosensitive mechanism. The algae were found to significantly accelerate the photodegradation rate of CTC and extracellular organic matters (EOMs) were confirmed to be the major active substances. Triplet state EOMs (3EOMs*) were verified to be the dominant reactive species with 93% contribution to the indirect photodegradation rate of CTC, while ·OH and 1O2 contributed minor (7%). The steady-state concentration of 3EOMs* was determined by probe compounds (2,4,6-trimethylphenol) to be 3.50 × 10−14∼1.88 × 10−13 M with the increase of EOMs from 2.0 to 8.0 mg L-1. The rate constant for reaction of 3EOMs* with CTC was calculated to be 3.17 × 109 M-1s-1. 3EOMs* were found to react with CTC mainly via electron transfer, on basis of susceptible reaction of 3EOMs* with the hydroxyl and amidogen groups in CTC. In addition, the energy transfer of 3EOMs* to CTC was possible according to the higher energy of 3EOMs* than that of triplet CTC.
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14203. 题目: Identification of Glycoproteins Isolated from Extracellular Polymeric Substances of Full-Scale Anammox Granular Sludge
文章编号: N18103108
期刊: Environmental Science & Technology
作者: Marissa Boleij, Martin Pabst, Thomas R. Neu, Mark C. M. van Loosdrecht, Yuemei Lin
更新时间: 2018-10-31
摘要: ANaerobic AMMonium OXidation (anammox) is an established process for efficient nitrogen removal from wastewater, relying on anammox bacteria to form stable biofilms or granules. To understand the formation, structure, and stability of anammox granules, it is important to determine the composition of the extracellular polymeric substances (EPS). The aim of this research was to elucidate the nature of the proteins, which are the major fraction of the EPS and were suspected to be glycosylated. EPS were extracted from full-scale anammox granular sludge, dominated by “Candidatus Brocadia”, and subjected to denaturing polyacrylamide gel electrophoresis. By further analysis with mass spectrometry, a high abundant glycoprotein, carrying a heterogeneous O-glycan structure, was identified. The potential glycosylation sequence motif was identical to that proposed for the surface layer protein of “Candidatus Kuenenia stuttgartiensis”. The heavily glycosylated protein forms a large fraction of the EPS and was also located by lectin staining. Therefore, we hypothesize an important role of glycoproteins in the structuring of anammox granules, comparable to the importance of glycans in the extracellular matrix of multicellular organisms. Furthermore, different glycoconjugates may have distinct roles in the matrix of granular sludge, which requires more in-depth characterization of different glycoconjugates in future EPS studies.
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14204. 题目: Enhanced Cu and Cd sorption after soil aging of woodchip-derived biochar: What were the driving factors?
文章编号: N18103107
期刊: Chemosphere
作者: Maria V. Rechberger, Stefanie Kloss, Shan-Li Wang, Johannes Lehmann, Harald Rennhofer, Franz Ottner, Karin Wriessnig, Gabrielle Daudin, Helga Lichtenegger, Gerhard Soja, Franz Zehetner
更新时间: 2018-10-31
摘要: Biochar (BC) is increasingly tested as a soil amendment for immobilization of heavy metals (HMs) and other pollutants. In our study, an acidic soil amended with wood chip-derived BC showed strongly enhanced Cu and Cd sorption after 15 months of aging under greenhouse conditions. X-ray absorption near edge structure suggested formation of Cu(OH)2 and CuCO3 and upon aging increasingly Cu sorption to the BC organic phase (from 9.2% to 40.7%) as main binding mechanisms of Cu on the BCs. In contrast, Cd was predominantly bound as CdCO3 on the BCs even after 15 months (82.7%). We found indications by mid-infrared spectroscopy that the formation of organic functional groups plays a role for increased HM sorption on aged BCs. Yet, our data suggest that the accessibility of BC's pore network and reactive surfaces is likely to be the overriding factor responsible for aging-related changes in HM sorption capacity, rather than direct interactions of HMs with oxidized functional groups. We observed highly weathered BC surface structures with scanning electron microscopy along with strongly increased wettability of the BCs after 15 months of soil aging as indicated by a decrease of water contact angles (from 62.4° to 4.2°).
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14205. 题目: Biochar and crushed straw additions affect cadmium absorption in cassava-peanut intercropping system
文章编号: N18103106
期刊: Ecotoxicology and Environmental Safety
作者: Luping Zeng, Xianke Lin, Fei Zhou, Junhao Qin, Huashou Li
更新时间: 2018-10-31
摘要: Cassava (Manihot esculenta Crantz) intercropped with peanut (Arachis hypogaea) has good complementary effects in time and space. In the field plot test, the land equivalent ratio (LER) of cassava-peanut intercropping system was 1.43, showing obvious intercropping yield advantage. Compared with monocropping, Cd contents in the roots of cassava and seeds of peanut were significantly reduced by 20.00% and 31.67%, respectively (p < 0.05). Under the unit area of hectare, compared with monocropping of cassava and peanut, the bioconcentration amount (BCA) of Cd in the intercropping system increased significantly by 24.98% and 25.59%, respectively (p < 0.05), and the metal removal equivalent ratio (MRER) of Cd was 1.25, indicating that the intercropping pattern had advantage in Cd removal. In the cement pool plot test, compared with the control, cassava intercropped with peanut under biochar and crushed straw additions did not only enhance the available nutrients and organic matter contents in rhizosphere soil but also promoted the crop growth and increased the content of chlorophyll (SPAD values) of plant leaves. The peanut seeds biomass under biochar and straw additions were significantly increased by 112.34% and 59.38% (p < 0.05), respectively, while the cassava roots biomass under biochar addition was significantly increased by 63.54% (p < 0.05). Applying biochar significantly decreased the content of Cd which extracted by diethylenetriaminepentaacetic acid (DTPA-Cd) in soil and reduced Cd uptake as well as translocation into plant tissues. The BCA of Cd of cassava under biochar addition decreased significantly by 53.87% in maturity stage (p < 0.05), thus reduced the ecological risk of Cd to crops and was of great significance to produce high quality and safe agricultural products. Besides, the crushed straw enhanced the biomass of crops, reduced Cd content in all tissues and maintained Cd uptake in the intercropping system. Therefore, it can realize the integration of ecological remediation and economic benefit of two energy plants in Cd contaminated soil after applied crushed straw in cassava-peanut intercropping system.
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14206. 题目: Vegetation effects on temperature calibrations of branched glycerol dialkyl glycerol tetraether (brGDGTs) in soils
文章编号: N18103105
期刊: Organic Geochemistry
作者: Jie Liang, James M. Russell, Haichao Xie, Rachel L. Lupien, Guicai Si, Jian Wang, Juzhi Hou, Gengxin Zhang
更新时间: 2018-10-31
摘要: Distributions of branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are sensitive to environmental parameters, which enables their use in paleoenvironmental studies. In particular, the degree of methylation of brGDGTs (MBT and MBT́) and the cyclization ratio of brGDGTs (CBT) are often used to estimate changes in temperature in paleoclimate studies. Application of these proxies requires reliable and precise calibrations to temperature. However, available calibrations of brGDGT proxies to temperature have large calibration errors in arid areas which suggests that other environmental variables influence brGDGT distributions in these areas. Here we analyze brGDGT distributions in soils from the Tibetan Plateau, an arid/semi-arid region with gradients in vegetation cover (forest, grassland, and desert) to examine: (1) the applicability of MBT́/CBT calibrations to reconstruct mean annual air temperature (MAAT); and (2) the effects of vegetation cover on temperature calibrations. We show that temperatures reconstructed using the global soil MBT́/CBT calibrations are warmer than instrumentally observed temperature, and that the calibrations are significantly influenced by the presence or absence of vegetation. Excluding sample sites without vegetation (bare soil) from temperature calibrations substantially improves the correlation between observed and reconstructed temperatures. Within the vegetated soils, we reanalyzed published global soil calibration datasets, including results of analyses that either did or did not separate 5- and 6-methyl brGDGT isomers, and find that the correlation between MBT́5Me and MBT́ and temperature varies for different vegetation types (grass and forest) and that the error of temperature calibrations is reduced if calibrations are separated by the type of vegetative cover (grass or forest). We test these new calibrations in sequences from the Lantian and Mangshan loess of the Chinese Loess Plateau and find that reconstructed temperatures from both modern and Last Glacial Maximum sediments are more consistent with other reconstructions and climate model simulations when vegetation-specific calibrations are applied to the brGDGT data. The results indicate that changes in vegetation should be taken into consideration when applying brGDGT proxies to reconstruct past changes in climate.

14207. 题目: Succession of soil macro-faunal biodiversity in forests converted from croplands after long-term coastal reclamation
文章编号: N18103104
期刊: Soil and Tillage Research
作者: Baoming Ge, Jun Cui, Daizhen Zhang, Qiuning Liu, Senhao Jiang, Boping Tang, Li Yang, Chunlin Zhou
更新时间: 2018-10-31
摘要: The long-term succession of the soil macro-faunal community after reclamation at coastal areas is not well understood, especially at the time scale of centuries. The objective of this work was to analyze soil development by measuring its principal physico-chemical properties and study the macro-faunal biodiversity succession along the successional trajectory created by intermittent reclamation. We hypothesized that soil macro-faunal taxonomic and functional diversity, richness, and density would increase after long-term reclamation, and that macro-faunal succession was related to dike age. In July 2014, sites of varying dike age (30, 50, 100, and 200 years) were used to represent a successional trajectory of Fluvisol soils at a reclaimed coast at Yancheng, China. The selected habitats were planted with 14–17 years old poplar (Populus euramericana) or dawn redwood (Metasequoia glyptostroboides) trees. With increasing dike age, soil nutrient status improved over the successional trajectory, as indicated by the increased soil organic carbon (SOC) concentration, total nitrogen (TN), and total phosphorous (TP). Soil salt concentration (SSC), pH, and carbon-nitrogen (C/N) ratio continuously decreased, as did soil bulk density (BD), the latter of which had a smaller coefficient of variation than the other properties did. Over the first 100 years of macro-faunal succession, taxonomic richness, abundance, Margalef’s richness index, and the Shannon-Weaver diversity index increased significantly, but did not differ significantly between the habitats with dike ages of 100 and 200 years. Significant differences in the measured communities’ characters were detected between forests planted with different trees when the dike age was 50 years but not when it was 30 years. Differences in macro-faunal community structure were primarily related to SOC and SSC, which were considerably related to dike age. The taxonomic richness and abundance of functional groups varied significantly among habitats and was related to changes in food resources in the soil environment. The abundance and taxonomic richness of phytophagous and saprophagous species increased with increasing dike age; no significant differences were noted in taxonomic richness of omnivorous species and predator abundance. The results thus supported our hypotheses. In conclusion, long-term macro-faunal community succession was affected by dike age, land use, and soil development after reclamation, and the soil macro-faunal biodiversity tended to increase with increasing dike age.

14208. 题目: Biochar improves soil quality and N2-fixation and reduces net ecosystem CO2 exchange in a dryland legume-cereal cropping system
文章编号: N18103103
期刊: Soil and Tillage Research
作者: Muhammad Azeem, Rifat Hayat, Qaiser Hussain, Mukhtar Ahmed, Genxing Pan, Muhammad Ibrahim Tahir, Muhammad Imran, Muhammad Irfan, Mehmood-ul-Hassan
更新时间: 2018-10-31
摘要: Biochar, a product of the pyrolysis of organic material, has received wide attention as a means to improve soil fertility, crop productivity, and carbon sequestration to mitigate climate change. This study was conducted in an arid zone agricultural region to investigate the impacts of biochar on soil quality, N2-fixation, and net ecosystem CO2 exchange (NEE) for a legume-cereal crop rotation (2013-15). Biochar was produced by pyrolysis of sugarcane bagasse and applied at rates of 0%, 0.25%, and 0.5% carbon (C) equivalent, with and without chemical fertilizer (23 kg N, 45 kg P and 25 kg K ha−1). In terms of soil quality, biochar applications increased soil organic carbon (SOC), total nitrogen (TN), and decreased soil bulk density. The yield of mash bean and wheat crop was significantly enhanced in response to biochar treatment with and without chemical fertilizer during both the years of study. N2-fixation in mash bean increased by 83% in biochar-only (0.5% C) amended soil and by 127% with chemical fertilizer. In the first year of mash bean, no difference was observed in NEE, while a significant decrease was observed in the second year attributed to priming effect of fresh biochar. Wheat NEE decreased by 144% and 200% in the first year, and by 283% and 265% in the second year, in unfertilized soil amended with 0.25 and 0.5% biochar, respectively, as compared to the controls. In treatments with chemical fertilizer, wheat NEE decreased by 311% and 344% in the first year, and by 293% and 292% in the second year, as compared to their respective controls. Biochar treatment increased biomass yield (BY) and grain yield (GY) in both mash bean and wheat crops during both the years with and without chemical fertilizer. These results indicate that sugarcane-bagasse biochar applications in arid soils with low organic carbon may increase crop productivity and N2-fixation of legumes while reducing the NEE of legume-cereal cropping systems.
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14209. 题目: Soil resistance to flowing water erosion of seven typical plant communities on steep gully slopes on the Loess Plateau of China
文章编号: N18103102
期刊: CATENA
作者: Bao-jun Zhang, Guang-hui Zhang, Han-yue Yang, Hao Wang
更新时间: 2018-10-31
摘要: Steep gully slopes are widespread and have been recognized as the main sediment source on the Loess Plateau. Different vegetation growth may lead to the differences in soil properties and plant roots, and thus likely affects soil resistance to flowing water erosion, reflected by rill erodibility and critical shear stress. However, few studies have been conducted to evaluate this effect on steep gully slopes on the Loess Plateau of China. This study was performed to investigate the effects of vegetation growth on soil resistance to flowing water erosion on steep gully slopes, and quantify the main potential influencing factors on the Loess Plateau. Three typical shrub communities and four typical grass communities that distributed on different gully slopes were selected. 240 undisturbed soil samples were collected from these seven gully slope lands and one slope farmland (control), and were subjected to detachment by overland flow under six different shear stresses (6.64 to 17.85 Pa). The results showed that the mean detachment capacity of slope farmland was 6.9 to 47.8 times greater than those of steep gully slopes covered with different plant communities. The rill erodibilities of steep gully slopes covered with different plant communities reduced greatly by 77.0% to 95.1% compared to the control slope. The critical shear stress of slope farmland (2.72 Pa) was only 57.2% and 39.6% of that of shrubland (4.76 Pa) and grassland (6.88 Pa). Both shrub and grass communities were effective in reducing soil detachment capacity and rill erodibility, and increasing critical shear stress on steep gully slopes. But the effects were more obvious for the grass communities. The differences in rill erodibility between slope farmland and gully slope lands were mainly explained by the changes in root mass density (82.4%). Plant roots had strong direct effects on increasing soil cohesion (0.78), organic matter content (0.56), and water stable aggregation (0.92). Rill erodibility was negatively related to root mass density as an exponential function (p < 0.05), and soil cohesion and water stable aggregation as power functions (p < 0.05). Critical shear stress was positively related to root mass density and soil water stable aggregation following a logarithmic function.

14210. 题目: Ornithogenic soils on basalts from maritime Antarctica
文章编号: N18103101
期刊: CATENA
作者: Mayara Daher, Carlos E.G.R. Schaefer, André Thomazini, Elias de Lima Neto, Caroline Delpupo Souza, Daví do Vale Lopes
更新时间: 2018-10-31
摘要: Large amounts of organic matter deposited by marine birds, especially penguins, accumulate on ice-free areas of maritime Antarctica during the short austral summer. The well-known ornithogenic soils of this region are unique in Antarctica and represent important sites where phosphatization is the main soil-forming process. Most recent studies in ornithogenic soils of maritime Antarctica were conducted on andesitic areas, and no reports are available about ornithogenic soils on basaltic intrusion. The purpose of this study was to report the main chemical, physical, and mineralogical characteristics of ornithogenic soils on basaltic intrusion of Barrientos, and evaluate the effects of different nesting bird species and altitude. The amount of Mehlich-extractable P indicates a close interaction between guano and underlying soils, with different end products depending on altitude, weathering degree and nesting bird species. In the soil collected from the giant petrel's nest, the intensity of organic deposition was much lower. The lower means of Mehlich-extractable P, total organic carbon and total nitrogen in Barrientos Island showed the little influence of marine birds when compared to King George Island. On the other hand, the means of exchangeable Ca and Mg were higher due to the basaltic composition of the regional volcanoes, contrasting with the andesites, which are the commonest rock type in maritime Antarctica. Thus, the soil characteristics of the Barrientos Island are influenced by both parent material and phosphatization.

14211. 题目: Uptake and Transfer of 13C-Fullerenols from Scenedesmus obliquus to Daphnia magna in an Aquatic Environment
文章编号: N18103007
期刊: Environmental Science & Technology
作者: Chenglong Wang, Xue-Ling Chang, Qiuyue Shi, Xian Zhang
更新时间: 2018-10-30
摘要: Fullerenol, a water-soluble polyhydroxylated fullerene nanomaterial, enters aquatic organisms and ecosystems through different ingestion exposures and may pose environmental risks. The study of their uptake routes and transfer in aquatic systems is scarce. Herein, we quantitatively investigated the aquatic uptake and transfer of 13C-fullerenols from Scenedesmus obliquus to Daphnia magna using 13C-skeleton-labeling techniques. The bioaccumulation and depuration of fullerenol in Daphnia magna increased with exposure doses and time, reaching steady state within 16 h in aqueous and feeding-affected aqueous routes. The capacity of Daphnia magna to ingest fullerenol via the aqueous route was much higher than that via the dietary route. From the aqueous to feeding-affected aqueous, the kinetic analysis demonstrated the bioaccumulation factors decreases, which revealed that algae suppressed Daphnia magna uptake of fullerenols. The aqueous route was the primary fullerenols ingestion pathway for Daphnia magna. Kinetic analysis of the accumulation and transfer in Daphnia magna via the dietary route indicated low transfer efficiency of fullerenol along the Scenedesmus obliquus-Daphnia magna food chain. Using stable isotope labeling techniques, these quantitative data revealed that carbon nanomaterials underwent complex aquatic accumulation and transfer from primary producers to secondary consumers and algae inhibited their transfer in food chains.
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14212. 题目: Toxicity of GO to Freshwater Algae in the Presence of Al2O3 Particles with Different Morphologies: Importance of Heteroaggregation
文章编号: N18103006
期刊: Environmental Science & Technology
作者: Jian Zhao, Yanhui Dai, Zhenyu Wang, Wenting Ren, Yongpeng Wei, Xuesong Cao, Baoshan Xing
更新时间: 2018-10-30
摘要: The roles of Al2O3 particles with different morphologies in altering graphene oxide (GO) toxicity to Chlorella pyrenoidosa were investigated. Algal growth inhibition by GO with coexisting Al2O3 particles was much lower than the sum of inhibitions from the individual materials for all the three Al2O3, showing the toxicity mitigation by Al2O3. The lowest GO toxicity was observed at the concentrations of 300, 150, and 100 mg/L for Al2O3 nanoparticles (NPs, 8–10 nm), bulk particles (BPs, 100–300 nm), and fibers (diameter: 10 nm; length: 400 nm), respectively. GO-Al2O3 heteroaggregation was responsible for the observed toxicity reduction. GO-induced algal membrane damage was suppressed by the three types of Al2O3 due to GO-Al2O3 heteroaggregation, and the reduction in intracellular reactive oxygen species generation and physical contact were confirmed as two main mechanisms. Moreover, the exposure sequence of GO and Al2O3 could highly influence the toxicity, and the simultaneous exposure of individual GO and Al2O3 showed the lowest toxicity due to minimum direct contact with algal cells. Humic acid further decreased GO-Al2O3 toxicity due to enhanced steric hindrance through surface coating of GO-Al2O3 heteroaggregates. This work provides new insights into the role of natural mineral particles in altering the environmental risk of GO.
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14213. 题目: Soil Organic Carbon Stabilization: Mapping Carbon Speciation from Intact Microaggregates
文章编号: N18103005
期刊: Environmental Science & Technology
作者: Maria C. Hernandez-Soriano, Ram C. Dalal, Frederick J. Warren, Peng Wang, Kathryn Green, Mark J. Tobin, Neal W. Menzies, Peter M. Kopittke
更新时间: 2018-10-30
摘要: The clearing of land for agricultural production depletes soil organic carbon (OC) reservoirs, yet despite their importance, the mechanisms by which C is stabilized in soils remain unclear. Using synchrotron-based infrared microspectroscopy, we have for the first time obtained in situ, laterally resolved data regarding the speciation of C within sections taken from intact free microaggregates from two contrasting soils (Vertisol and Oxisol, 0–20 cm depth) impacted upon by long-term (up to 79 y) agricultural production. There was no apparent gradient in the C concentration from the aggregate surface to the interior for any of the three forms of C examined (aliphatic C, aromatic C, and polysaccharide C). Rather, organo-mineral interactions were of critical importance in influencing overall C stability, particularly for aliphatic C, supporting the hypothesis that microaggregates form through organo-mineral interactions. However, long-term cropping substantially decreased the magnitude of the organo-mineral interactions for all three forms of C. Thus, although organo-mineral interactions are important for OC stability, C forms associated with the mineral phases are not entirely resistant to degradation. These results provide important insights into the underlying mechanisms by which microaggregates form and the factors influencing the persistence of OC in soils.
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14214. 题目: Characterization and ecotoxicological investigation of biochar produced via slow pyrolysis: effect of feedstock composition and pyrolysis conditions
文章编号: N18103004
期刊: Journal of Hazardous Materials
作者: Xiao Yang, Weicheng Ng, Belinda Shu Ee Wong, Gyeong Hun Baeg, Chi-Hwa Wang, Yong Sik Ok
更新时间: 2018-10-30
摘要: This study systematically investigated the biochar toxicity from the in vitro tests involving the use of human liver and lung cell lines, as well as in vivo tests using Drosophila melanogaster (fruit fly). Biochars used in this study were produced from vegetable waste, pine cone and their mixture (1:1 by weight) at two representative temperatures (200 and 500 °C). Two common toxicant groups in biochar, heavy metals (HM) and polycyclic aromatic hydrocarbons (PAHs) contents, were detected for clarification of the relationship between their toxicity behaviors and biochar bulk characteristics. The results showed that 1) no HMs can be found in the biochar if HMs are absence in their feedstock 2) PAHs were formed during the pyrolysis no matter what type of biomss used, but the concentration is low that can be acceptable for soil legislative criteria 3) biochars had limited impact to the viability of flies, but inhibited the growth of the cells 4) the low leaching potential of HMs and PAHs (total 16 USEPA) in the studied biochars may not be the major reason which put the harm to the cell, more effort on the identification need to be done. This work can provide a new picture to the biochar researchers for better understanding of the two faces of biochar.

14215. 题目: Temperature sensitivity of microbial Fe(III) reduction kinetics in subalpine wetland soils
文章编号: N18103003
期刊: Biogeochemistry
作者: Kathrin Schilling, Thomas Borch, Charles C. Rhoades, Céline E. Pallud
更新时间: 2018-10-30
摘要: Microbially-mediated iron (Fe) cycling controls the fate of organic matter, contaminants, and nutrients in terrestrial ecosystems including wetland soils. However, the effects of temperature variations due to seasonal differences on Fe(III) reduction rates and kinetics in such ecosystems remains poorly understood. To evaluate the potential temperature impact on dissimilatory microbial Fe(III) reduction it is crucial to determine environmentally-relevant reaction rates and kinetic parameters. Here, we investigate the relationship between soil temperature and microbial Fe(III) reduction kinetics in mineral soils from two subalpine wetlands with distinct hydrologic and edaphic conditions. We conducted flow-through experiments (FTR) at three temperatures (6, 12, and 18 °C) using intact soil cores collected from 30 cm [(higher organic carbon (Corg) and total nitrogen (TN)] and 70 cm (lower Corg and TN) soil depths in order to determine the apparent Fe(III) affinity constant (Km), apparent maximum Fe(III) reduction rates (Vmax) and temperature sensitivity (Q10 and Ea) of Fe(III) reduction. We used Fe(III)-NTA, a model compound for aqueous labile and complexed Fe present in natural organic matter. Our results show that changes in apparent Vmax and Km are driven primarily by temperature. Significant differences in apparent Vmax at 18 °C relative to 6 and 12 °C (P < 0.05) suggest that dissimilatory microbial Fe(III) reduction in wetland soils accelerates during warmer summer days. However, temperature alone fails to explain the large variability of the apparent parameters Q10 (1.5–8.9) and Ea (26–148 kJ mol−1) for the two wetland types and depths (30 and 70 cm). Strong relationship between both parameters of temperature sensitivity (Q10 and Ea) and reactive soil Fe content at 30 cm and Corg/TN at 70 cm depth demonstrate the notable impact of soil properties on the temperature sensitivity for mirobial Fe(III) reduction in these wetland soils. Our results emphasize the importance of soil temperature on Fe(III) reduction kinetics and must be considered when predicting dissimilatory Fe(III) reduction under different seasonal temperatures or in wetlands located at different temperature regimes.

14216. 题目: TECHNOLOGICALLY ACHIEVABLE SOIL ORGANIC CARBON SEQUESTRATION IN WORLD CROPLANDS AND GRASSLANDS
文章编号: N18103002
期刊: Land Degradation & Development
作者: Niels H. Batjes
更新时间: 2018-10-30
摘要: Reported potentials for sequestration of carbon in soils of agricultural lands are overly optimistic because they assume that all degraded cropland and grassland can be subjected to best management practices. Two approaches for estimating this potential are presented. Method 1 (M1) considers literature‐derived best estimates for annual SOC gains (Mg C ha‐1) by bioclimatic zone; method 2 (M2) assumes an annual C increase of 3 to 5 pro mille with respect to present SOC mass (similar to the French ‘4‐pour‐mille’ initiative). Four management scenarios are considered, capturing the varying level of plausibility of meeting the full technological potential. According to M1, achievable gains range from 0.05‐0.12 Pg C yr‐1 to 0.14‐0.37 Pg C yr‐1, with a technological potential of 0.32‐0.86 Pg C yr‐1. For M2, these are 0.07‐0.12 Pg C yr‐1, 0.21‐0.35 Pg C yr‐1 and 0.60‐1.01 Pg C yr‐1. Consideration of the technological potential only and use of a proportional annual increase in SOC (M2), rather than using best estimates for soil carbon gains by bioclimatic zone (M1), will provide too ‘bright a picture’ in the context of rehabilitating degraded lands and mitigating/adapting to climate change. Further, M2 assumes that possible C gains will be greatest where present SOC stocks are highest, which is counter‐intuitive. Although all measures aimed at increasing SOC content should be encouraged due to the creation of win‐win situations, it is important to create a realistic picture of the amount of SOC gains that are feasible, based on bioclimatic and management implementation constraints.

14217. 题目: Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
文章编号: N18103001
期刊: CATENA
作者: Verena A. Campodonico, Andrea I. Pasquini, Karina L. Lecomte, M. Gabriela García, Pedro J. Depetris
更新时间: 2018-10-30
摘要: Subtropical laterites are partially found in the Argentinian province of Misiones, covering the Jurassic-Cretaceous Serra Geral flood basalts (known as Posadas Formation in Argentina). Two hypotheses have been proposed to explain the origin of these laterites. The autochthonous theory attributes the origin of these deposits to the chemical weathering of the underlying tholeiitic basalts. However, during the last decade, an allochthonous “tropical loess” model was proposed. Several mineralogical/geochemical characteristics of a lateritic profile (~2 m thick, 26°9′58″S–54°35′3″W) are analyzed in this paper in order to constrain the nature of weathering processes in this region and the provenance of the lateritic layer. The basaltic bedrock at the sampling site exhibits intergranular texture and is mainly composed of clinopyroxene, plagioclase and opaque minerals (likely titanomagnetite and ilmenite). Altered glass and apatite were also identified in lower proportions. The X-ray diffraction of the clay-size fraction shows prevailing kaolinite and hematite in the most altered samples, complemented by amorphous Fe-Al (hydr)oxides. Serra Geral basalts-normalized spidergrams and mass balance calculations confirmed almost complete losses of all major oxides (i.e., ~50 g of material was removed by weathering from each 100 g of the original basalt) and depletions of some trace elements (e.g., Sc, V, Sr, Cr, Ni, Rb and U) in the uppermost and intermediate layers of the lateritic profile, reflecting the weathering of feldspars, clinopyroxenes, volcanic glass and apatite. In contrast, some elements are enriched in the topmost and intermediate layers, due to intrinsic immobility during weathering (e.g., Zr, Hf, Ta, Th) or adsorption onto clays (e.g., Cs). Rare earth elements (REEs) are depleted in the top layers and enriched in the middle section of the profile. The preferential leaching of REEs from the uppermost levels during weathering and its accumulation in the middle section can be caused by a pH increase in this level, the decomposition of organic matter and the consequent precipitation of REEs which exhibit an affinity to form aqueous organic complexes, or the presence of Fe and Mn (hydr)oxides in the intermediate level. Weathering intensity was appraised by means of different alteration indices, which showed the extreme leaching endured by the basaltic bedrock. The index of lateritization (IOL), which ranges between 35 and 55, and the accompanying SAF ternary plot (SiO2-Al2O3-Fe2O3), indicate an increasing weathering trend towards the profiles' top, reflecting the modest loss of SiO2 (relative to Al2O3 and Fe2O3) during kaolinitization. The geochemical approach used to constrain the origin of the lateritic mantle that partially covers Misiones province, clearly relates the analyzed laterites to the underlying tholeiitic basalts, supporting the autochthonous origin theory.

14218. 题目: Role of a non-ionic surfactant and carboxylic acids on the leaching of aged DDT residues in undisturbed soil columns
文章编号: N18102905
期刊: Journal of Soils and Sediments
作者: Mariana Gonzalez, Francesca Maria Mitton, Karina Silvia Beatriz Miglioranza, Aránzazu Peña
更新时间: 2018-10-29
摘要: Purpose: Irrigation or flooding events with riverine waters containing compounds such as surfactants, colloids, and dissolved organic carbon and plant growth will modify pesticide availability and leaching. This work studies the effect of a non-ionic surfactant (Tween 80: polyethylene glycol sorbitan monooleate, Tw-80), carboxylic acids (CA), and the role of dissolved organic matter on the lixiviation, availability, and degradation of aged DDT (p,p′-DDT, p,p′-DDE and p,p′-DDD) residues in soil. Materials and methods: Undisturbed soil columns were collected in a known polluted area and irrigated under saturation conditions with 4 L of riverine water (control), Tween 80 at 0.5 times the critical micellar concentration (Tw-80), and a 0.05 M solution of oxalic and citric acids (CA). After elution, columns were air-dried (24 h), opened, and divided into 5-cm sections for pesticide residue analysis in soil by GC-ECD. Batch desorption studies were conducted to assess pesticide availability before treatments. Metabolite ratios were analyzed in relation with the soil microbial activity measured by the dehydrogenase activity (DHA) assay. Soil organic matter and dissolved organic matter were analyzed, and humic substances were characterized in terms of humic and fulvic acid content by spectrophotometric ratios. Results and discussion: The p,p′-DDE>p,p′-DDT>p,p′-DDD pattern was found in all soil sections and treatments with decreased levels with depth. Levels of p,p-DDE ranged between 8 and 280, between 8 and 80, and between 13 and 250 ng g−1 dry weight in control, Tw-80, and CA, respectively. Lixiviation of p,p-DDE was enhanced in Tw-80 or CA. Compared to control, elution with Tw-80 diminished effectively soil DDT levels, while with CA results showed an enhancement of the transference to water. Higher (p,p′-DDE + p,p′-DDD)/p,p′-DDT ratio in Tw-80 or CA soils, with respect to control, were related with higher p,p′-DDD and DHA levels in CA and with lower p,p′-DDE and p,p′-DDT levels in Tw-80. Control and CA showed a positive correlation between p,p′-DDE and p,p′-DDT soil levels and desorption (r > 0.8, p < 0.02). Losses of fulvic acid content in soil after Tw-80 agree with the enrichment in fulvic acids in the desorption solution. Conclusions: The influence of Tw-80 and CA on the availability of DDTs was related with the mobilization of organic matter fractions. Results highlight the role of the non-ionic surfactant Tw-80 in the mobilization of fulvic acids as well as on DDT desorption from soil. Both solutions might interact differentially with pesticides and with the soil microbial population controlling the fate of DDT residues in the soil matrix.

14219. 题目: Biochar amendment of chromium-polluted paddy soil suppresses greenhouse gas emissions and decreases chromium uptake by rice grain
文章编号: N18102904
期刊: Journal of Soils and Sediments
作者: Jiangmin Zhou, Hualin Chen, Yueliang Tao, Ronald W. Thring, Jianliang Mao
更新时间: 2018-10-29
摘要: Purpose: Soil chromium (Cr) pollution has received substantial attention owing to related food chain health risks and possible promotion of greenhouse gas (GHG) emissions. The aim of the present study was to develop a promising remediation technology to alleviate Cr bioavailability and decrease GHG emissions in Cr-polluted paddy soil. Materials and methods: We investigated the potential role of biochar amendment in decreasing soil CO2, CH4, and N2O emissions, as well in reducing Cr uptake by rice grains at application rates of 0 t ha−1 (CK), 20 t ha−1 (BC20), and 40 t ha−1 (BC40) in Cr-polluted paddy soil in southeastern China. In addition, the soil aggregate size distribution, soil organic carbon (SOC) concentration of soil aggregates, soil available Cr concentration, and rice yield were analyzed after harvesting. Results and discussion: Biochar amendment significantly reduced CO2, CH4, and N2O emission fluxes. Compared to CK, total C emissions in the BC20 and BC40 treatments decreased by 9.94% and 17.13% for CO2-C, by 30.46% and 37.10% for CH4-C, and by 34.24% and 37.49% for N2O-N, respectively. Biochar amendment increased the proportion of both the 2000–200 μm and 200–20 μm size fractions in the soil aggregate distribution. Accordingly, the organic carbon concentration of these fractions increased, which increased the total SOC. Moreover, biochar amendment significantly decreased soil available Cr concentration and total Cr content of the rice grains by 33.6% and 14.81% in BC20 and 48.1% and 33.33% in BC40, respectively. Rice yield did not differ significantly between biochar amendment treatment and that of CK. Conclusions: Biochar application reduced GHG emissions in paddy soil, which was attributed to its comprehensive effect on the soil properties, soil microbial community, and soil aggregates, as well as on the mobility of Cr. Overall, the present study demonstrates that biochar has a great potential to enhance soil carbon sequestration while reducing Cr accumulation in rice grains from Cr-polluted rice paddies.

14220. 题目: Short term recovery of vegetation and soil after abandoning cultivated mixedgrass prairies in Alberta, Canada
文章编号: N18102903
期刊: CATENA
作者: Haibo An, Bin Zhang, Ben W. Thomas, Ryan Beck, Walter D. Willms, Yuejin Li, Xiying Hao
更新时间: 2018-10-29
摘要: Cultivating native rangeland can have detrimental effects on soil carbon and nitrogen storage. Understanding how vegetation and soil recover after returning marginal cultivated land to its native state is important since soil plays a key role not only in food production but also in regulating global climate change. Soil samples were taken from two sites, a mixedgrass and a dry mixedgrass prairie, which have different climates and plant species composition. Each study site included one undisturbed native plot (CK) and two cultivated treatments that were abandoned in 2008 after being cultivated for more than ten years prior to this study, one with continuous wheat (Triticum aestivum L.) and the other with wheat-fallow rotations. Soil organic carbon (SOC), total nitrogen (TN), and labile organic fraction content were measured in 2016, while plant coverage and species diversity were investigated in 2017. In both study sites, grass and sedge coverage in the previously cultivated treatments were lower than, with shrub and forb coverage similar to, the CK. The highest invasive species coverage appeared in the previously cultivated treatments. Species richness was higher with CK in the mixedgrass prairie but no differences were found in the more arid dry mixedgrass prairie. No differences were found among all treatments for species evenness, Simpson's index and Shannon–Wiener index. On average, in the 0–15 cm depth, SOC and TN contents with the previous cultivated treatments were still 20% and 16% lower than CK, respectively, whereas in the 15–30 cm depth, SOC and TN contents did not differ among all treatments except for SOC content in the mixedgrass prairie. Relative to CK, previously cultivated treatments had similar active carbon (AC), microbial respiration-carbon and NH4+-N contents but the mixedgrass prairie had lower water extractable-organic carbon and water extractable-nitrogen. In contrast, in the dry mixedgrass prairie all labile organic fraction contents, except for AC, were the same among all treatments. Negative relationships were found between plant diversity and surface soil carbon and nitrogen storage. Our results indicate that for short-term disturbed rangeland, 9 years is likely sufficient for the recovery of soil labile organic fractions and plant diversity but a longer time will be needed for the recovery of SOC and TN.

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