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8221. 题目: Immobilized microalgae for anaerobic digestion effluent treatment in a photobioreactor-ultrafiltration system: Algal harvest and membrane fouling control
文章编号: N18080210
期刊: Bioresource Technology
作者: Binghan Xie, Weijia Gong, Huarong Yu, Xiaobin Tang, Zhongsen Yan, Xinsheng Luo, Zhendong Gan, Tianyu Wang, Guibai Li, Heng Liang
更新时间: 2018-08-02
摘要: A photobioreactor (PBR) coupled with ultrafiltration (UF) system was developed with goals of microalgae cultivation, harvest, and membrane fouling control in the anaerobic digestion effluent purification. Firstly, three-sequencing batch PBRs were started-up with suspended Chlorella vulgaris (C. vulgaris, SCV), immobilized C. vulgaris (ICV) and immobilized C. vulgaris with powdered activated carbon (ICV + PAC). The results exhibited high DOC degradation (66.61%–84.35%) and completely nutrients (nitrogen and phosphorus) removals were attained in PBRs. This indicated bacterial-microalgal consortiums enhanced biodegradation and PAC adsorption accelerated photodegradation. During the microalgae harvest by UF, immobilized microalgae beads protected cells integrity with less debris and intracellular/extracellular organic matters lysis. Moreover, the cake layer in ICV + PAC could even serve as a dynamic layer to entrap the residual pollutants and control membrane fouling. Hence, membrane fouling mitigation and ADE purification were realized during the microalgae harvest process in the ICV + PAC.
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8222. 题目: Lignin-induced growth inhibition in soybean exposed to iron oxide nanoparticles
文章编号: N18080209
期刊: Chemosphere
作者: Tamires Letícia Cunha Lopes, Rita de Cássia Siqueira-Soares, Guilherme Henrique Gonçalves de Almeida, Gabriele Sauthier Romano de Melo, Gabriela Ellen Barreto, Dyoni Matias de Oliveira, Wanderley Dantas dos Santos, Osvaldo Ferrarese-Filho, Rogério Marchiosi
更新时间: 2018-08-02
摘要: Plants are occasionally exposed to environmental perturbations that limit their growth. One of these perturbations is the exposure to and interaction with various nanoparticles (NPs) that are discarded continuously into the environment. Hitherto, no study has been carried out evaluating the effects of iron oxide (γ-Fe2O3) NPs on soybean growth and lignin formation, as proposed herein. For comparative purposes, we also submitted soybean plants to non-nanoparticulate iron (FeCl3). Exposure of the plants to γ-Fe2O3 NPs increased cell wall-bound peroxidase (POD) activity but decreased phenylalanine ammonia lyase (PAL) activity due, probably, to the negative feedback of accumulated phenolic compounds. In contrast, FeCl3 decreased cell wall-bound POD activity. Both γ-Fe2O3 NPs and FeCl3 increased the lignin content of roots and stems. However, significant lignin-induced growth inhibition was noted only in stems after exposure to NPs, possibly due to changes in lignin monomer composition. In this case, γ-Fe2O3 NPs decreased the guaiacyl monomer content of roots but increased that of stems. The high levels of monomer guaiacyl in stems resulting from the action of γ-Fe2O3 NPs decreased syringyl/guaiacyl ratios, generating more highly cross-linked lignin followed by the stiffening of the cell wall and growth inhibition. In contrast, FeCl3 increased the contents of monomers p-hydroxyphenyl and syringyl in roots. The observed increase in the syringyl/guaiacyl ratio in plant roots submitted to FeCl3 agrees with the lack of effect on growth, due to the formation of a less condensed lignin. In brief, we here describe that γ-Fe2O3 NPs and FeCl3 act differently in soybean plants.
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8223. 题目: Winter road management effects on roadside soil and vegetation along a mountain pass in the Adirondack Park, New York, USA
文章编号: N18080208
期刊: Journal of Environmental Management
作者: Hanna M. Willmert, Joseph D. Osso, Michael R. Twiss, Tom A. Langen
更新时间: 2018-08-02
摘要: In 2003-2005, we resurveyed and expanded plots surveyed in 1985 to examine the cumulative impact of road salt (sodium chloride) and sand along a two-lane highway in the Adirondack State Park in New York State (USA). Annual salt applications in the period 1985-2005 ranged from 50 tonnes per centerline-km (1985) to 140 tonnes (2005) and sand applications ranged from nearly zero tonnes (2005) to 325 tonnes (1985). Roadside soils and vegetation were significantly impacted by salt deposition compared to soils and vegetation 30 meters and 150 meters from the road. Roadside soil contained more sand, less organic matter, had a lower cation exchange capacity, was denser, and retained less water than soils 30 m and 150 m from the road. The concentration of sodium in roadside soils was elevated (103 vs. 44 ppm in soil 150 m from the roadside), and roadside concentrations of plant-nutritive cations were lower than 150 m from the road (roadside Mg, Ca and K concentrations were 0.2, 5, and 1 ppm respectively vs. 23,168, and 30 ppm at 150 m from the road). Along the roadside, paper birch trees (Betula papyrifera) and other woody vegetation present in 1980 were absent in 2004, suggesting that survival and recruitment of paper birch trees was impacted by degradation of soil fertility, deposition of road salt and aerosolization of salt from the roadway. Roadside environmental degradation caused by winter road management has worsened since 1980; revegetation with native salt-tolerant plants may provide some mitigation of the most severe effects. Overall, we conclude that the full extent of roadside environmental degradation caused by winter road management can take decades to manifest, and this may be the case more generally along cold-climate montane roadways.

8224. 题目: Steroid fingerprints: efficient biomarkers of human decomposition fluids in soil
文章编号: N18080207
期刊: Organic Geochemistry
作者: Barbara von der Lühe, Jago J. Birk, Lorna Dawson, Robert W. Mayes, Sabine Fiedler
更新时间: 2018-08-02
摘要: The decomposition of animal and human cadavers can lead to comprehensive chemical and biochemical changes in soil, which can provide helpful information for the analysis of archaeological and crime scenes. The current study focused specifically on the concentration and distribution patterns of steroids in soil with the aim of assessing their suitability for demonstrating the presence of human decomposition products. Soil samples were collected from a forensic site where a human corpse had been lying on the soil surface for 18 days. Total organic carbon (TOC) and steroid concentrations were analysed in soil samples taken from beneath the body at the time the corpse was removed and also one year later. High concentrations of TOC and steroids were detected close to the soil surface at the time the body was removed, and the concentration of cadaver-derived cholesterol was considerably higher than that of the plant-derived sitosterol. The soil beneath the cadaver contained higher concentrations of faeces-derived 5β-stanol coprostanol than the control soil. Different concentrations and distribution patterns of steroid compounds in the soil upon removal of the corpse and one year later indicate that significant transformation, degradation and translocation processes had taken place during this period of time. The depth distribution of steroids beneath a decomposing body along with changes in the human steroidal fingerprints in soil over time were found to provide information that could help resolve forensic and archaeological issues. The combined analysis of tissue steroids (cholesterol), the reduction product of cholesterol in soil (5α-cholestanol) as well as faecal steroids (coprostanol, 5β-stigmastanol and their conversion products epicoprostanol and epi-5β-stigmastanol) represent excellent additions to the forensic toolbox for determining whether a soil of interest has ever been affected by a human cadaver or not.

8225. 题目: Radically different lignin composition in Posidonia species may link to differences in organic carbon sequestration capacity
文章编号: N18080206
期刊: Organic Geochemistry
作者: Joeri Kaal, Oscar Serrano, José C. del Río, Jorge Rencoret
更新时间: 2018-08-02
摘要: There is considerable variability in the ability of seagrass ecosystems to sequester organic carbon (Corg) in their sediments, which act as natural carbon sinks contributing to climate change mitigation. In this work, we studied the chemistry of two Posidonia seagrass species aiming to elucidate whether differences in chemical composition might explain differences in their Corg sequestration capacity. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and Thermally assisted Hydrolysis and Methylation (THM) GC-MS data showed a remarkable difference in phenolic compound patterns between P. oceanica and P. australis bulk plants and individual organs (leaves, sheaths, roots and rhizomes). The lignin of P. australis generates a series of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) products that are typical of herbaceous plants, whereas P. oceanica is particularly rich in p-hydroxybenzoic acid (pBA) derivatives. The structural characteristics of the lignins were further investigated by two-dimensional Nuclear Magnetic Resonance (2D-NMR) and Derivatization Followed by Reductive Cleavage (DFRC), focusing on sheath tissues. The analyses confirmed important differences in the lignin content (19.8% in P. australis and 29.5% in P. oceanica) and composition between the two species; intriguingly, the cell-walls of P. oceanica sheaths were highly enriched in pBA, a component that was completely absent in P. australis. 2D-NMR and DFRC further revealed that pBA was esterified to the lignin, acylating the γ-OH of the lignin side-chain. Interestingly, P. oceanica lignin presented an extremely high degree of p-hydroxybenzoylation in both guaiacyl (73%) and syringyl (61%) lignin units, the highest p-hydroxybenzoylation degree reported in plant lignins to date. It is tempting to conclude that the higher soil Corg storage capacity of P. oceanica ecosystems might be related to the higher abundance of pBA-rich lignin and its recalcitrant nature.

8226. 题目: Depositional environment of the Late Santonian lacustrine source rocks in the Songliao Basin (NE China): Implications from organic geochemical analyses
文章编号: N18080205
期刊: Organic Geochemistry
作者: Xiaoning Tong, Jianfang Hu, Dangpeng Xi, Mengbo Zhu, Jianzhong Song, Ping'an Peng
更新时间: 2018-08-02
摘要: The Songliao Basin (SLB) located in northeastern China is one of the largest Cretaceous continental sedimentary basins in the world. The SLB is filled with sediments deposited in the Upper Jurassic, the Lower Cretaceous and the Upper Cretaceous epochs. The Nenjiang Formation (K2n) is subdivided into five members, where Member 2 (K2n2) was deposited in the late Santonian in the lower part of the Nenjiang Formation. This member is characterized by a thick succession of organic-rich source rocks. However, the complexity of the depositional environment raises questions about the specific factors that drove this accumulation of organic material. Here, we present data on the total organic carbon (TOC) contents and their stable carbon isotope values (δ13Corg), as well as biomarker data from 50 outcrop samples collected from the Yuewangcheng (YWC) section, in the southeastern SLB. According to the variations of the bulk organic parameters (TOC and δ13Corg) and biomarker indices, the profile could be divided into three stages (stages I–III). The distribution of biomarkers (n-alkanes, steranes and hopanes) and δ13Corg values indicate that the organic matter (OM) in the Lower K2n2 is derived largely from algae and macrophytes, with a minor input from bacteria and land plants. The water column was stratified, as indicated by the presence of gammacerane. Variations in the pristane/phytane (Pr/Ph) and aryl isoprenoids relative to phenanthrene ratio (A-i/P) suggest that bottom waters were anoxic during Stage I (31.5–26.0 m) and Stage II (26.0–16.3 m), with the anoxic layer impinging on the euphotic zone and a relative oxic environment at Stage III (16.3–0 m). This brackish environment persisted in the water over the interval represented by the section, as reflected by methytrimethyltridecyl chromans (MTTCs) Index (MTTCI) and α-MTTC/γ-MTTC ratios. Marine transgressions, with subsequent seawater incursions, can be detected with the presence of 24-n-propyl-cholestanes and 24-iso-propyl-cholestanes in the Lower K2n2 sediments, especially during Stage I. These seawater incursions are closely correlated with anoxic conditions and the deposition of organic-rich source rocks.

8227. 题目: Effect of salinity on the decomposition of soil organic carbon in a tidal wetland
文章编号: N18080204
期刊: Journal of Soils and Sediments
作者: Wendi Qu, Juanyong Li, Guangxuan Han, Haitao Wu, Weimin Song, Xiaoshuai Zhang
更新时间: 2018-08-02
摘要: Purpose: Climate warming and sea level rise have the potential to change the salt level of soil in tidal wetlands. And it is important to clarify the process and the mechanism of decomposition of soil organic carbon in a tidal wetland under varying salinities. The aim of this study was to evaluate the impacts of soil salinity on the decomposition rate of organic carbon (DROC) and dissolved organic carbon (DOC) in a tidal wetland. Materials and methods: Two types of soil (surface soil in Suaeda salsa and bare tidal flat) were collected, air-dried, and homogenized. After adding different content of salt (0 g/L, 3 g/L, 6 g/L, 9 g/L, and 12 g/L), the soils were incubated for 28 days at stable room temperature (25 ± 2 °C) and added by deionized water to maintain the stability of soil moisture. The gases (CO2 and CH4) emission rates of each salt treatment were measured during 28-day incubation. DROC was determined by the sum of daily CO2-C emission rates and daily CH4-C emission rates in this study. Results and discussion: Salt addition inhibited the process of gas emissions and DROC. Gases emission rates and DROC of two types of soil showed similar temporal trends, with distinctive drop in the beginning of experiment and no significant decrease followed. Significant difference of DOC among salt treatments was found in the bare tidal flat soil. Variations of partial correlation between DROC and soil salinity and DOC showed similar trends (e.g., in days 9–18, the positive effect of DOC on DROC was greatly promoted (R2 = 0.80, p < 0.001), and the negative effect of soil salinity was highly improved (R2 = 0.93, p < 0.001)). Soil properties, in particular DOC, may be primary factors accounting for the discrepancy of gases emission rates and DROC of two types of soil. Conclusions: Increased soil salinity had a negative effect on DROC during 28-day incubation. The impact of soil salinity and DOC on DROC were varied in different phases of laboratory experiment (soil salinity generally had increasingly negative relationship with DROC, but DOC showed most significantly positive relationship in the middle stage of incubation). Both the formation and consumption of DOC may be valuable for more detail research regarding to decomposition of soil organic carbon.

8228. 题目: Distribution, dynamics and determinants of antibiotics in soils in a peri-urban area of Yangtze River Delta, Eastern China
文章编号: N18080203
期刊: Chemosphere
作者: Fangkai Zhao, Liding Chen, Lei Yang, Shoujuan Li, Long Sun, Xinwei Yu
更新时间: 2018-08-02
摘要: Antibiotics are increasingly recognized as anthropogenic contaminants in soils, and they can persist through a complex vicious cycle of transformation and bioaccumulation. In this study, we quantified 11 quinolones (QNs), 5 sulfonamides (SAs), 5 macrolides (MLs), and 4 tetracyclines (TCs) in soils at three soil layers (0–10, 10–20, 20–40 cm) in a typical peri-urban catchment in the Yangtze River Delta, Eastern China. The results showed that total antibiotic levels were significantly higher in cropland topsoil (p < 0.05) compared to orchards and forests (p < 0.05). Moreover, a significant seasonal variation for antibiotic concentrations in croplands’ topsoil were observed in the summer (50.59 ± 84.55 ng/g) and winter (112.44 ± 140.58 ng/g). Chlortetracycline (15.30 ± 45.44 ng/g), enrofloxacin (0.43 ± 0.93 ng/g), sulfamethazine (0.05 ± 0.02 ng/g) and clarithromycin (0.03 ± 0.03 ng/g) were detected with the highest frequencies within TCs, QNs, SAs, and MLs, respectively. Concentrations of TCs, QNs, and SAs decreased with increasing soil depth. The concentrations of TCs, QNs, and SAs were significantly affected by the intensity of human activities. According to the results of redundancy analysis (RDA), anthropogenic effects on the distribution of antibiotics in soils in winter were so strong that they dwarfed the effects of environmental factors. In summer, human activities and their interactions with environmental factors were the dominant contributors to variations in soil antibiotics. In addition, the results of RDA suggested that soil pH and organic matter closely correlated with the levels of antibiotics, and Actinobacteria was the predominant contributor to the biodegradation of antibiotics in this study area.
图文摘要:

8229. 题目: Visible-light-driven photocatalytic degradation of ciprofloxacin by a ternary Mn2O3/Mn3O4/MnO2 valence state heterojunction
文章编号: N18080202
期刊: Chemical Engineering Journal
作者: Jianhui Zhao, Zhiwei Zhao, Ning Li, Jun Nan, Ruixin Yu, Jinying Du
更新时间: 2018-08-02
摘要: Valence state heterostructure exhibits great potential for contaminants remediation from water and wastewater with effective charge separation and little energy loss. However, the preparation process commonly shows complex with uncontrolled manner, forming undesired valence states, which hinders the advancement of valence state heterostructure. Herein, an Oxone induced strategy is established to controllably design manganese-based valence state heterostructure for the first time. A superior Mn2O3/Mn3O4/MnO2 (molar ratio of 3:1:2) photocatalyst with dual Ⅱ heterostructures was generated by Oxone (0.3 mM) induced Mn2O3 (0.2 g/L) under visible light. The Mn2O3/Mn3O4/MnO2 heterojunction achieved 95.6% removal and 63.9% mineralization of ciprofloxacin (cipro) under visible light irradiation for 40 min. The excellent catalytic performance was derived from the improved surface area, decreased isoelectric point, enhanced light absorption and efficient charge separation of the Mn2O3/Mn3O4/MnO2 heterostructure. Moreover, the radicals trapping experiment and Electron paramagnetic resonance (EPR) measurement revealed the dominant roles of holes and superoxide radicals for cipro degradation. Furthermore, the reusable Mn2O3/Mn3O4/MnO2 could remove cipro selectively with co-existing natural organic matters and inorganic ions, which exhibited high practicability in real waters. Impressively, this work provides an innovative approach for controllable design of valence state heterostructure and fabricates a promising photocatalyst towards antibiotics degradation.
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8230. 题目: Influence of organic management on As bioavailability: Soil quality and tomato As uptake
文章编号: N18080201
期刊: Chemosphere
作者: Silvia Rita Stazi, Roberto Mancinelli, Rosita Marabottini, Enrica Allevato, Emanuele Radicetti, Enio Campiglia, Sara Marinari
更新时间: 2018-08-02
摘要: The research studied the effects of organic vs. conventional management of soil quality and tomato yield quality, cultivated in a geogenic arsenic contaminated soil. The chemical and biochemical properties were analyzed to evaluate soil quality, arsenic mobility and its phyto-availability, as well as arsenic accumulation in the tomato plant tissues and if tomatoes cultivated in arsenic rich soil represents a risk for human health. A general improvement of tomato growth and soil quality was observed in the organic management, where soil organic carbon increased from 1.24 to 1.48% and total nitrogen content. The arsenic content of the soil in the organic management increased from 57.0 to 65.3 mg kg−1, probably due to a greater content of organic matter which permitted the soil to retain the arsenic naturally present in irrigation water. An increase of bioavailable arsenic was observed in the conventional management compared to the organic one (7.05 vs 6.18 mg kg−1). The bioavailable form of metalloid may affect soil microbial community structure assessed using El-FAME analysis. The increase of the total arsenic concentration in the organic management did not represent a stress factor for soil microbial biomass carbon (Cmic), which was higher in the organic management than in the conventional one (267 vs. 132 μg Cmic g−1). Even if the organic management caused an increase of total arsenic concentration in the soil due to the enhanced organic matter content, retaining arsenic from irrigation water, this management mitigates the arsenic uptake by tomato plants reducing the mobility of the metalloid.

8231. 题目: The interplay between natural organic matter and bromide on bromine substitution
文章编号: N18080110
期刊: Science of The Total Environment
作者: Mahmut S. Ersan, Chao Liu, Gary Amy, Tanju Karanfil
更新时间: 2018-08-01
摘要: This study examined the interplay between bromide and DOM characteristics, described with SUVA254, in terms of formation and speciation of selected DBPs [trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs)] during chlorination under various water treatment conditions. Cytotoxicity evaluations were also conducted based on the types and amounts of DBPs formed and their corresponding cytotoxicity index values. The results showed that the formation of THMs and HAAs increased as the specific UV absorbance at 254 nm (SUVA254) of the waters increased; however, there was no clear trend for HANs. THM and HAN formation increased with increasing bromide levels, while there was no bromide effect on the HAA formation. Lower HAA5 (monochloroaceticacid, monobromoaceticacid, dichloroaceticacid, trichloroaceticacid, dibromoaceticacid) to HAA9 (monochloroaceticacid, monobromoaceticacid, dichloroaceticacid, trichloroaceticacid, dibromoaceticacid, bromochloroaceticacid, bromodichloroaceticacid, dibromochloroaceticacid, tribromoaceticacid) ratios, independent of SUVA254, were observed with increasing bromide levels. Bromine substitution factor (BSF) values were in the order of BSFDHAN > BSFTHAA > BSFTHM ≈ BSFDHAA. BSF values for all class of DBPs decreased with increasing SUVA254. TOX formation increased with increasing SUVA254 without an impact of bromide concentration. UTOX/TOX ratios were higher in treated low SUVA254 waters than raw waters having higher SUVA254 values, and they decreased with increasing initial bromide concentration in all sources. Increasing bromide concentration from 0.5 μM to 10 μM elevated the calculated cytotoxicity index values of waters. Despite their much lower (approximately ~10 times) formation as compared to THMs and HAAs, HANs controlled the calculated cytotoxicity of studied waters.
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8232. 题目: The influence of aging on the comparative terrestrial ecotoxicity potential of copper and zinc in soils
文章编号: N18080109
期刊: Environmental Science and Pollution Research
作者: Aiju Liu, Qiang Liao, Mingzhu Li, Menghong Li, Zilin Meng, Qian Zhang, Huansheng Cao
更新时间: 2018-08-01
摘要: Metal exposure to terrestrial organism is influenced by the reactivity of the solid-phase metal pool. Aging is one of the important factors that control the reactivity of the solid-phase metal pool in soil. In this study, the selected 13 soils were collected from different locations of China, representing different soil types. The reactivity variation of spiked Cu and Zn with aging was assessed in these 13 soils, and their comparative toxicity potentials (CTPs) were also calculated. The median reactive fractions (freactive) of Cu and Zn with 95% confidence intervals were 1.6 × 10−2 (3.5 × 10−6 to 2.2 × 10−1) and 0.10 (9.1 × 10−4 to 0.44) kgreactive/kgtotal, and the median CTPs for Cu and Zn were 2.09 (8.1 × 10−4 to 2.2 × 104) and 0.85 (8.5 × 10−4 to 7.2 × 102) m3/kg day, respectively. The statistical analysis indicated that aging variability in the CTP of Cu and Zn was mainly associated with the variability in soil organic carbon and pH. These results stress the importance of dealing with aging in the calculation of CTPs for terrestrial ecotoxicity of metals.

8233. 题目: Vertical and seasonal variations of soil carbon pools in ginkgo agroforestry systems in eastern China
文章编号: N18080108
期刊: CATENA
作者: Jing Guo, Bo Wang, Guibin Wang, Yaqiong Wu, Fuliang Cao
更新时间: 2018-08-01
摘要: Agroforestry provides opportunities to decrease the levels of carbon dioxide (CO2) released into the atmosphere by increasing the carbon (C) stored in agricultural systems. In agroforestry systems, soil C pools serve as the most important and stable C sink, but there is limited information on the vertical and seasonal variations of soil C pools. In this study, the vertical and seasonal variations of soil organic C (SOC) and its labile pools were measured in five planting systems: a pure ginkgo (Gingko biloba. L) planting system, a pure wheat (Triticum aestivum L.) field, a pure metasequoia (Metasequoia glyptostroboides Hu et Cheng) seedling system, a ginkgo and wheat agroforestry system, and a ginkgo and metasequoia seedling agroforestry system. Among these systems, the ginkgo and wheat system had a significantly higher SOC content than the other systems throughout the year, particularly at depths of 0–10 cm and 10–20 cm. Additionally, the pure ginkgo and pure metasequoia systems had lower SOC contents than the other planting systems, and this decrease was attributed to the relatively limited tree litter input and lower fine root biomass. Microbial biomass C (MBC) and soil readily oxidizable C (ROC) exhibited similar vertical and seasonal variations and reached minimum values in winter. The highest MBC and ROC contents were observed in the ginkgo and wheat system at a depth of 0–10 cm, i.e., 127.3 mg kg−1 and 4.49 g kg−1, respectively. The highest water-soluble organic carbon (WSOC) content was observed in summer at a depth of 0–10 cm, i.e., 472.2 mg kg−1. A Pearson correlation analysis indicated that soil properties were significantly correlated with SOC and labile C fractions. The results suggested that an agroforestry system resulted in a greater increase in the soil C sink; in particular, the ginkgo and wheat system achieved the best results. Basic soil properties played key roles in soil carbon formation. These results provide important information about SOC and labile C fraction dynamics resulting from planting systems and depth variations and strengthen our understanding of soil C sequestration in agroforestry systems.

8234. 题目: Effects of mixed surfactants on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in crops and the bioremediation of contaminated farmlands
文章编号: N18080107
期刊: Science of The Total Environment
作者: Zhiheng Li, Wei Wang, Lizhong Zhu
更新时间: 2018-08-01
摘要: Given the widespread contamination of polycyclic aromatic hydrocarbons (PAHs) in farmland, it is necessary to develop a technology to ensure the safety of agricultural productions and remediate the contaminated soils. In this study, a series of mixed surfactants were utilized to reduce the uptake of PAHs by crops in farming period and enhance the plant-microbe associated biodegradation in fallow period. During the farming period, the mixtures of cetyltrimethyl ammonium bromide (CTMAB) and Tween 80 were attached on soil by cationic-exchange and hydrogen bond, respectively, which increased soil organic matter to partition the bio-available fraction of PAHs. The maximum reduction of phenanthrene and pyrene was 88.6% and 94.9% for chrysanthemum (Chrysanthemum coronarium L.), and 90.6% and 91.9% for raphanus (Raphanus sativus L.), respectively. During the fallow period, sodium dodecyl benzene sulfonate (SDBS) reduced the adsorption loss of Tween 80 on soil to enhance desorption of PAHs. The mixtures of SDBS and Tween 80 increased the water-soluble fraction of PAHs in soils, modified bacterial community structure, and enriched the functional genes involved cell motility and signal transduction. Removal efficiencies of phenanthrene and pyrene in soils were high to 86.7% and 90.7%. This systematic technology provided an effective solution to remediate and plant on PAH-contaminated farmlands.
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8235. 题目: Framework for Cost-Effective Prediction of Unregulated Disinfection By-Products in Drinking Water Distribution Using Differential Free Chlorine
文章编号: N18080106
期刊: Environmental Science: Water Research & Technology
作者: Gyan Chhipi Shrestha, Manuel J. Rodriguez, Rehan Sadiq
更新时间: 2018-08-01
摘要: Unregulated disinfection by-products (U-DBPs) in drinking water are formed primarily by the reaction of disinfectants (e.g., chlorine) and natural organic matter (NOM). The formation can be dictated by basic water quality and operational parameters. This purpose of this study was to develop a cost-effective framework for predicting U-DBP concentration in water distribution networks (WDNs) based on changes in free chlorine in the WDN with respect to that at the water treatment plant (WTP) outlet (called differential free chlorine, i.e., Cl2). Under the framework, mixed-effects models were developed to predict U-DBP families: haloacetonitriles (HANs) and haloketones (HKs) and individual compounds: chloropicrin (CPK), dichloroacetonitrile (DCAN), borochloroacetonitrile (BCAN), and 1,1,1 trichloropropanone (TCP). Common water quality parameters at the WTP outlet were also included to increase the effectiveness of the models. The models developed were applied successfully to two applications: a single large-sized and combined medium-sized water systems with the R2 of predictive models up to 0.95 and a 95% confidence interval of percent difference in the predictions of -27% to 32%. These applications show that Cl2 only or with basic water quality parameters at WTP are effective parameters for estimating U-DBP concentration in WDNs. The proposed framework can be used by water utilities as a low-cost method to develop models for their water systems to identify potential locations to monitor U-DBPs. Moreover, the frameworks can be used by public health organizations to assess population exposure to U-DBPs in drinking water.

8236. 题目: No difference in ectomycorrhizal morphotype composition between abandoned and inhabited nests of wood ants (Formica polyctena) in a central European spruce forest
文章编号: N18080105
期刊: Geoderma
作者: Veronika Jílková, Martin Vohník, Ondřej Mudrák, Hana Šimáčková, Jan Frouz
更新时间: 2018-08-01
摘要: In temperate forest ecosystems, ectomycorrhizal (EcM) fungi substantially support coniferous trees by nutrients, but importance of EcM for tree nutrition might be lower in nutrient-rich hotspots, such as in wood ant nests. In this study, we focused on differences in EcM morphotype composition between natural nutrient-rich hot spots of various quality (inhabited vs. abandoned wood ant nests) and the surrounding forest floor. In a secondary Norway spruce forest typical for central Europe, we took samples from different belowground parts of five inhabited and five abandoned nests (centre and rim) as well as from the forest floor 20 cm from the nests (run-off zone) and >3 m from the nests (forest soil). The substrates were subjected to analyses of the EcM morphotype composition, moisture and nutrient contents. Wood ant nest substrates had several times increased nutrient contents compared to the forest soil, but there were no significant differences in moisture. Available nutrient contents were higher in inhabited nests than in abandoned nests. The EcM morphotype composition differed between the nest samples and the forest floor samples but not between the inhabited and abandoned nests suggesting that, apart from the level of nutrient enrichment and their availability, moisture is another important factor affecting EcM community composition.

8237. 题目: Biochars mediated degradation, leaching and bioavailability of pyrazosulfuron-ethyl in a sandy loam soil
文章编号: N18080104
期刊: Geoderma
作者: Suman Manna, Neera Singh
更新时间: 2018-08-01
摘要: Burning of crop residues after harvest is a quick, cheap and an easy way to manage the large quantities of agricultural biomass for timely preparation of the field for next crop. Conversion of the crop harvest residues into biochars and incorporating them back in the same field can address the issue of land clearing, waste utilization and nutrient conservation but, any amendment to the soil changes its physico-chemical characteristics and can affect the fate of soil applied herbicides. The present study reports the effect of low (400 °C) and high (600 °C) temperature wheat (WBC) and rice (RBC) straw biochar's amendment on leaching, degradation and bioavailability of pyrazosulfuron-ethyl (PYRAZO) in a sandy loam soil. The PYRAZO was poorly retained in the control soil column where 78% of the soil-applied herbicide leached out of the control soil column. Biochars addition (0.02 and 0.05 g kg−1) significantly reduced the PYRAZO leaching by affecting herbicide's breakthrough time and its maximum concentration in leachate.
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8238. 题目: Characterizing dissolved organic matter in eroded sediments from a loess hilly catchment using fluorescence EEM-PARAFAC and UV–Visible absorption: Insights from source identification and carbon cycling
文章编号: N18080103
期刊: Geoderma
作者: Chun Liu, Zhongwu Li, Asmeret Asefaw Berhe, Haibing Xiao, Lin Liu, Danyang Wang, Hao Peng, Guangming Zeng
更新时间: 2018-08-01
摘要: The chemical characteristics of dissolved organic matter (DOM) in soils that experience erosion and deposition are key to the biogeochemical cycle of carbon on the earth's surface. However, data related to the transport and fate of DOM from soils that experience erosion and different management practices are scarce, particularly at catchment scales. In this study, soil samples (uppermost 10 cm) were collected from uplands representing four land use types (cropland, fallow, grassland, and forests) as well as gullies, and sediment samples (100 cm sampled at 10 depths) were collected from sediments retained by a check dam. Chemical characteristics of DOM in soils and sediments, as well as subsequent source identification, were inferred from UV–Visible absorption and fluorescence excitation emission matrix (EEM)-parallel factor analysis (PARAFAC) as well as principal component analysis (PCA). The results indicated higher aromaticity, hydrophobic fraction, and molecular size in DOM from forest soils than those from other land use types and gullies. These factors were also higher in soils at the eroding sites than in sediments. EEM-PARAFAC analysis demonstrated that more protein-like components (tyrosine-like and tryptophan-like combined, accounting for >42.77%) were present in sediments compared to soils with terrestrial humic-like substances. PCA results revealed that approximately 72% of the variance in the DOM characteristics was explained by the first two principal components and that the DOM in upland and gully soils had a negligible contribution to DOM in sediments. Combined our results indicate that, despite the large amount of sediment-associated carbon that is transported by erosion and trapped in check dams, DOM is likely mineralized during soil transport. Furthermore, biological production of new organic compounds (autochthonous sources) are likely the major source of sediment DOM in depositional settings.

8239. 题目: Anaerobic organic carbon mineralization in tidal wetlands along a low-level salinity gradient of a subtropical estuary: Rates, pathways, and controls
文章编号: N18080102
期刊: Geoderma
作者: Min Luo, Wenfeng Zhu, Jiafang Huang, Yuxiu Liu, Xun Duan, Jie Wu, Chuan Tong
更新时间: 2018-08-01
摘要: To examine how the rates and pathways of anaerobic organic carbon mineralization (AOCM) of tidal freshwater wetlands change with low-level increases in salinity, we investigated the rates and controls of microbial iron and sulfate reduction, methane production, and total AOCM in tidal wetlands along a freshwater to oligohaline (0.1–3.3 ppt) gradient in the Min River Estuary in southeastern China. Porewater chloride was found to be strongly correlated with total organic carbon (TOC), carbon to nitrogen (C:N) ratios, and porewater geochemistry (sulfate, pH, ammonium, and dissolved methane levels). Furthermore, a higher plant biomass, larger iron oxides pool, and lower sulfide levels were observed in the oligohaline wetlands. The contribution of microbial sulfate reduction to AOCM increased from 16% to 67%. In contrast, the contribution of microbial iron reduction and methane production declined from 52% to 22% and 12% to 2%, respectively, along the increasing salinity gradient. No consistent changes were found in the total AOCM rates. The rates of methane production were primarily controlled by the C:N ratios and concentrations of porewater ammonium and amorphous iron oxides, while the microbial sulfate and iron reduction rates were mainly controlled by belowground biomass, water content, and concentrations of porewater chloride and sulfate. Our findings provide insight into the potential consequences of modest saltwater intrusion; these may not alter the rates of AOCM in the Min River Estuary, but could change the dominant AOCM pathway from microbial iron reduction to sulfate reduction and accelerate sulfidic effects in this historically freshwater wetland ecosystem.
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8240. 题目: The occurrence, distribution and degradation of antibiotics by ionizing radiation: An overview
文章编号: N18080101
期刊: Science of The Total Environment
作者: Jianlong Wang, Run Zhuan, Libing Chu
更新时间: 2018-08-01
摘要: Antibiotics have been extensively applied, making them ubiquitous in aquatic environment. As emerging contaminants, the occurrence and distribution of antibiotics in the environment has received increasing attention due to their potential adverse effects on human health and ecosystem. However, antibiotics cannot be effectively removed in conventional biological treatment processes, and their natural biodegradation is also ineffective. In this review, the occurrence and distribution of antibiotics in aquatic environments, including surface water, wastewater and effluent of wastewater treatment plants, were analyzed and summarized. Recent progress of antibiotics degradation by ionizing radiation was reviewed. The various influencing factors, such as absorbed dose, initial concentration, inorganic anions and organic matters, on the removal efficiency of antibiotics were introduced and discussed. To improve their removal efficiency, several advanced oxidation processes (AOPs) such as H2O2, Fe2+, Fe2+/H2O2, as well as biological treatment processes, are combined with ionizing radiation. Some suggestions for future studies of antibiotics degradation by ionizing radiation were proposed. Ionizing radiation may be a promising technology for removal of antibiotics from water and wastewater.
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