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12921. 题目: Seasonal changes in plankton respiration and bacterial metabolism in a temperate shelf sea
文章编号: N19092401
期刊: Progress in Oceanography
作者: E. Elena García-Martín, Chris J. Daniels, Keith Davidson, Clare E. Davis, Claire Mahaffey, Kyle M.J. Mayers, Sharon McNeill, Alex J. Poulton, Duncan A. Purdie, Glen A. Tarran, Carol Robinson
更新时间: 2019-09-24
摘要: The seasonal variability of plankton metabolism indicates how much carbon is cycling within a system, as well as its capacity to store carbon or export organic matter and CO2 to the deep ocean. Seasonal variability between November 2014, April 2015 and July 2015 in plankton respiration and bacterial (Bacteria + Archaea) metabolism is reported for the upper and bottom mixing layers at two stations in the Celtic Sea, UK. Upper mixing layer (UML, >75 m in November, 41–70 m in April and ∼50 m in July) depth-integrated plankton metabolism showed strong seasonal changes with a maximum in April for plankton respiration (1.2- to 2-fold greater compared to November and July, respectively) and in July for bacterial production (2-fold greater compared to November and April). However UML depth-integrated bacterial respiration was similar in November and April and 2-fold lower in July. The greater variability in bacterial production compared to bacterial respiration drove seasonal changes in bacterial growth efficiencies, which had maximum values of 89% in July and minimum values of 5% in November. Rates of respiration and gross primary production (14C-PP) also showed different seasonal patterns, resulting in seasonal changes in 14C-PP:CRO2 ratios. In April, the system was net autotrophic (14C-PP:CRO2 > 1), with a surplus of organic matter available for higher trophic levels and export, while in July balanced metabolism occurred (14C-PP:CRO2 = 1) due to an increase in plankton respiration and a decrease in gross primary production. Comparison of the UML and bottom mixing layer indicated that plankton respiration and bacterial production were higher (between 4 and 8-fold and 4 and 7-fold, respectively) in the UML than below. However, the rates of bacterial respiration were not statistically different (p > .05) between the two mixing layers in any of the three sampled seasons. These results highlight that, contrary to previous data from shelf seas, the production of CO2 by the plankton community in the UML, which is then available to degas to the atmosphere, is greater than the respiratory production of dissolved inorganic carbon in deeper waters, which may contribute to offshore export.

12922. 题目: Application of biochar and its composites in catalysis
文章编号: N19092304
期刊: Chemosphere
作者: Honghong Lyu, Qianru Zhang, Boxiong Shen
更新时间: 2019-09-23
摘要: With a wide range of raw materials, low cost and large specific surface area, biochar has been widely used in environmental remediation. However, the biochar has a saturated adsorption capacity when it is used as a pollutant adsorbent. Recent efforts have been made to prepare biochar and biochar-based catalysts with enhanced catalytic properties to expand their potential applications. The environmental persistent free radicals (EPFRs) of biochar could react with O2 to induce hydroxyl radicals (•OH) without the addition of oxidants. When oxidants were added, biochar and biochar-based catalysts could activate them to generate •OH and sulfate radicals (SO4•−), respectively. Moreover, biochar could act as an electron acceptor to improve the photodegradation capacity of catalysts. With reference to the information regarding biochar and biochar-based catalysts, this work provides a critical review on recent research development as follows: 1) the preparations of various types of biochar and biochar-based catalysts are summarized; 2) the effects of the synthetic conditions and transition metals on the catalytic activity of biochar-based catalysts are discussed; (3) methods for characterizing the active sites of the biochar-based catalysts are described; and (4) the environmental applications of biochar and biochar-based catalysts are discussed with regards to three aspects based on the interaction mechanisms, namely, oxidation, reduction, and photocatalysis. The synthesis conditions and loading of metal/metal-free catalyst are key parameters controlling the catalysis activity of biochar and biochar-based catalysts. This review provides new insights into the application of biochar in catalysis. Key challenges and further research directions are proposed as well.
图文摘要:

12923. 题目: Spectrum evolution of dissolved aromatic organic matters (DAOMs) during electro-peroxi-coagulation pretreatment of coking wastewater
文章编号: N19092303
期刊: Separation and Purification Technology
作者: Xin Zhou, Zilong Hou, Jingjing Song, Lin Lv
更新时间: 2019-09-23
摘要: Enormous existence of dissolved aromatic organic matters (DAOMs) is considered to be a major cause that coking wastewater is hardly degraded. In this study, an advanced electro-chemical process i.e. electro-peroxi-coagulation (EPC) was developed as a pretreatment for efficiently degrading DAOMs and improving the biodegradability of the raw coking wastewater. Gas chromatography-mass spectrometry (GC-MS) also confirmed that most of DAOMs (phenolics, heterocycles, polycyclic aromatic hydrocarbons, benzenes, organic nitriles and anilines) could be effectively decomposed by EPC pretreatment. Ultraviolet visible (UV-Vis), Fourier transform infrared spectroscopy (FTIR) and excitation-emission matrix (EEM) consistently found remarkable spectrum variations of DAOMs in the first 15 min, while spectrum changes became gentle until 2 h. The spectrum evolution of DAOMs suggests the strong attacks on the benzene rings and unsaturated bonds of DAOMs occurs initially and then low molecule intermediates are further degraded. Therefore, EPC should be a feasible option for coking wastewater pretreatment based on the combination of electro-oxidation and electro-precipitation.
图文摘要:

12924. 题目: Coupled retention of bovine serum albumin and NOM by porous membranes
文章编号: N19092302
期刊: Separation and Purification Technology
作者: Lanlan Qin, Haiou Huang
更新时间: 2019-09-23
摘要: Coupled retention of natural organic matter (NOM) is an important process in membrane water treatment. A mechanistic understanding is lacking due to the complex nature of NOM. In this study, filtration experiments were conducted with the mixture of bovine serum albumin (BSA) and Suwannee River NOM (SRNOM) through different pore-sized membranes. A macroscopic depth filtration theory was utilized for analyzing the underlying mechanisms. The results showed the importance of BSA-SRNOM interactions on NOM retention. At a neutral pH of 7.0, the co-existing SRNOM reduced BSA retention by up to 24% by mitigating concentration polarization and inner-pore BSA deposition. Meanwhile, the presence of BSA elevated SRNOM retention by up to 23% because of SRNOM adsorption onto the deposited BSA, as well as enhanced steric hindrance and concentration polarization effect. Furthermore, the reduction of solution pH to 3.7 enhanced BSA-SRNOM interactions that favored multilayer BSA/SRNOM deposition. As a result, BSA and SRNOM retention increased by 54% and 79 %, 78% and 37 %, and 48% and 10% for membranes having pore radii of 7.5 nm, 15 nm and 25 nm, respectively. This study demonstrated that the interplay of concentration polarization, steric hindrance, and inner-pore deposition governed NOM retention by porous membranes.

12925. 题目: Long-term stacking coal promoted soil bacterial richness associated with increased soil organic matter in coal yards of power plants
文章编号: N19092301
期刊: Journal of Soils and Sediments
作者: Congcong Shen, Dawei Ma, Ruibo Sun, Benyao Zhang, Delin Li, Yuan Ge
更新时间: 2019-09-23
摘要: Purpose: Coal exploitation inevitably brings a chain of ecological problems, e.g., land destruction and biodiversity decrease. Most previous studies have investigated the ecological effect of coal mining process and the ecological restoration after coal mining practice. However, no study has concerned about the potential influence of long-term stacking coal process on soil microbial communities, the pivotal components to maintain the health of terrestrial ecosystems. This study aims to investigate the influence of long-term stacking coal on soil microbial communities, as well as the time effect. Materials and methods: We collected soil samples from coal yards of four power plants (representing four stacking time: 10, 28, 31, and 71 years) in Huainan city. Soils in the lawn near each coal yard were also selected as control at four sites. Soil microbial communities were analyzed via 16S and 18S rRNA gene sequencing. Results and discussion: Our results showed that long-term stacking coal significantly (P < 0.05) increased soil organic matter (SOM), and thus facilitated soil bacterial richness and the shifts of bacterial community composition. We also detected significant (P < 0.05) increase of SOM, bacterial richness, and community dissimilarity with stacking time, indicating a substantial time effect. Meanwhile, predicted functional data implied that stacking coal activated anaerobic microbial communities by forming an anaerobic environment in soils. Conclusions: Together, these data provide basic knowledge of the potential influence of long-term stacking coal on soil microbial communities and reinforce the role of SOM in shaping bacterial community composition and richness.

12926. 题目: The Sources of Organic Matter in Seagrass Sediments and Their Contribution to Carbon Stocks in the Spermonde Islands, Indonesia
文章编号: N19092207
期刊: Aquatic Geochemistry
作者: Yusmiana P. Rahayu, Tubagus Solihuddin, Mariska A. Kusumaningtyas, Restu Nur Afi Ati, Hadiwijaya L. Salim, Tim Rixen, Andreas A. Hutahaean
更新时间: 2019-09-22
摘要: Seagrass ecosystems have a potential role in climate change mitigation due to their ability to store high amount of carbon, particularly in the sediment. Studying the factors and mechanisms responsible for this storing capacity is essential to understand seagrass carbon sink function. Therefore, in this study, we identified the sources of organic carbon (Corg) in seagrass sediments and the implication to Corg stocks from four islands in the Spermonde Islands that located at different zones. We used the Bayesian stable isotope mixing model to estimate the proportional contribution of different sources to sediment carbon. Seagrass meadows that located in adjacent to high anthropogenic activities (deforestation and aquacultures) with direct exposure to wave actions, such as on the Bauluang Island, accumulated organic carbon that derived from multiple sources, where phytoplankton contributed the highest, while on the other three islands that are relatively protected from wave actions, the highest contribution (~ 75%) was from autochthonous production (seagrass-derived). Sediment Corg stocks vary spatially, ranging from 11.9 to 32.1 Mg C ha−1 (based on the obtained depth of 20–55 cm), or 40.5 to 83.5 Mg C ha−1 if extrapolated to 1 m depth. The variability of sediment properties and Corg stocks in this study is not solely determined by the geographical differences (inshore, nearshore and offshore islands), but also influenced by other local factors such as hydrodynamics that control the distribution of carbon sources, anthropogenic pressures and species composition. These factors should be taken into account when developing coastal management strategies, as efforts are being undertaken to include coastal ecosystems (including seagrass ecosystems) on the National Green House Gasses Reduction Strategy.

12927. 题目: Sulfur controlled cadmium dissolution in pore water of cadmium-contaminated soil as affected by DOC under waterlogging
文章编号: N19092206
期刊: Chemosphere
作者: Guoxi Wang, Zhengyi Hu, Songyan Li, Yan Wang, Xiaolei Sun, Xiangru Zhang, Meng Li
更新时间: 2019-09-22
摘要: Cadmium (Cd) precipitation and dissolution in pore water is associated with dissolved organic carbon (DOC)-induced reduction-oxidation of sulfur (S) under waterlogging and is vital for controlling the bioavailability in paddy soil. A 120-day soil incubation experiment, including application of sulfur (S, 30 mg kg−1) and wheat straw (W, 1.0%) alone or in combination (W + S) into Cd-contaminated paddy soil under waterlogging, was conducted to investigate the dynamic of dissolved Cd and its relationship with DOC, S2−, Fe2+, pH, Eh and pe + pH in soil pore water. The results showed that the lowest dissolved Cd concentration was observed in the W + S-treated soil pore water among all treatments when the soil Eh remained at lower values during the period of 15–60 days of incubation, which could be attributed to CdS precipitation and/or co-precipitation of Cd absorbed by FeS2 because of the reduction in sulfur. The application of S resulted in a Cd rebound in the pore water irrespective of W addition when the Eh began to increase from its lowest values during the period of 45–75 days of incubation, and SOB genera were observed in the S added soil. This could be attributed to re-dissolution of the precipitated Cd in soils under the SOB-driven oxidation of sulfide such as CdS and FeS2. In conclusion, DOC-driven reduction-oxidation of sulfur controls Cd dissolution in the pore water of Cd-contaminated paddy soil under waterlogging conditions. Further studies are required to investigate the interaction of sulfur and SOM-induced DOC on Cd bioavailability in rice-planted paddy soils.

12928. 题目: Low-molecular-weight organic acids enable biochar to immobilize nitrate
文章编号: N19092205
期刊: Chemosphere
作者: Natalie Heaney, Emem Ukpong, Chuxia Lin
更新时间: 2019-09-22
摘要: Batch experiments were conducted using two biochar materials produced from different feedstocks to examine the behavior of solution-borne nitrate in the presence and absence of three model low-molecular weight organic acids (LMWOAs). The results showed that the biochar materials alone were not able to remove the solution-borne nitrate. LMWOAs caused protonation of the biochar surfaces and consequently enabled the biochar materials to adsorb nitrate from the solution. Different types of LMWOA had different capacities to immobilize solution-borne nitrate. Over 80% of the solution-borne nitrate could be removed within 72 h in the presence of citric acid or malic acid. By comparison, removal rate of nitrate was lower in the presence of oxalic acid, possibly due to competition of oxalate ion with nitrate for the available adsorption sites on the biochar surfaces. Nitrate adsorption onto the MSP700 biochar in the presence of all three-LMWOAs followed first order and second order kinetics, suggesting that the immobilization of nitrate involved complex interplay of physisorption and chemisorption. Nitrate adsorption onto RH700 biochar in citric and malic acid treatment systems followed second order kinetics. In the presence of oxalic acid for both biochar materials, nitrate adsorption showed perfect correlation R2 = 1 for both models.

12929. 题目: pH dependence of the binding interactions between humic acids and bisphenol A - A thermodynamic perspective
文章编号: N19092204
期刊: Environmental Pollution
作者: Li-hong Gan, Zi-run Yan, You-fei Ma, Yu-ying Zhu, Xiu-yan Li, Juan Xu, Wei Zhang
更新时间: 2019-09-22
摘要: The wide application of bisphenol A (BPA) leads to the emergence of BPA residuals in natural water environments. Dissolved organic matter (DOM) existed in water can bind with BPA, hence influencing the migration and transformation of BPA in aquatic environments. pH is a crucial factor governing the binding interactions between DOM and BPA. However, the mechanisms driven the binding process under different pH conditions are still unclear. In this study, the interactions between BPA and humic acids (HA), a primary component of DOM, are investigated over a wide pH range of 3–12 by integrating fluorescence quenching, dynamic light scattering and microcalorimetry. pH dependence of the binding interactions between HA and BPA are interpreted from a thermodynamic perspective. The results indicate that HA can spontaneously interact with BPA to form a stable HA-BPA complex. With the increasing pH, the binding interactions change from entropy driven to entropy-enthalpy co-driven. Hydrophobic force dominate the binding interactions under acidic condition. The synergy of hydrophobic force and hydrogen bond promotes the binding process under neutral condition. Under alkaline condition, electrostatic repulsion participates the binding process in addition to hydrophobic force and hydrogen bond, weakening the binding strength. Therefore, neutral pH is favorable for HA to bind with BPA, consequently enhancing the dissolution of BPA in natural water bodies. The results are beneficial to better understand the pH dependent distribution of BPA in aquatic environments.
图文摘要:

12930. 题目: Sludge dewaterability: The variation of extracellular polymeric substances during sludge conditioning with two natural organic conditioners
文章编号: N19092203
期刊: Journal of Environmental Management
作者: Marie Christine Amie Sene Faye, Kai Kai Zhang, Sun Peng, Yanrong Zhang
更新时间: 2019-09-22
摘要: To assess the characteristics of Extracellular Polymeric Substances during natural organic conditioners for sludge treatment, Moringa oleifera (MO) and chitosan (CTS) were used as conditioners. The findings of this study show that despite the high EPS content due to the fact that this component is not destroyed upon conditioning, sludge conditioned with MO and CTS displayed efficient and improved dewaterability. MO and CTS showed the same mechanism of action by protonation of the negatively charged EPS and reduction of electrostatic repulsions between sludge flocs, thus enhancing sludge filterability by neutralizing and settling. The effect of MO and CTS on EPS lies in their ability to neutralize EPS, settling them. MO and CTS neutralize and aggregate the EPS, hence improving sludge dewaterability. The results indicate that CTS can impact the EPS quantity and quality while MO impacts the EPS quality. Understanding the impact of MO and CTS on sludge EPS can help elucidate the mechanism of their dewaterability efficiency.

12931. 题目: Composition change and adsorption performance of EPS from Bacillus vallismortis sp. induced by Na2S
文章编号: N19092202
期刊: Ecotoxicology and Environmental Safety
作者: Qiuhua Li, Weifeng Song, Mengge Sun, Jiayao Li, Zefeng Yu
更新时间: 2019-09-22
摘要: Sodium sulfide (Na2S) was used as an inducer to regulate the components of Bacillus vallismortis sp. EPS (Extracellular Polymeric Substances). The main objective of this study was to improve the content of sulfhydryl protein and the adsorption property of EPS to Zn (Ⅱ) that as an typical heavy metal. The results showed that the maximum EPS production of 105.58 mg/g VSS coupling with doubled increase in protein in which the contant of -SH increased by 48.2% from 104.15 to 154.36 μmol/L were recorded in the presence of 20 mg/L Na2S. Under this condition, the adsorption capacity of S-EPS (EPS with added exogenous Na2S) for Zn (Ⅱ) was highest. The kinetics of the adsorption process of Zn (Ⅱ) by the S-EPS can be well fitted by the Langmuir isotherm model and the theoretical maximum adsorption amount of 979.09 mg/g EPS could be obtained. The results of 3D-EEM and FTIR analyses, illustrated that -SH, CO, and N-H/C-N played major roles in the removal of Zn (Ⅱ) by S-EPS. The results obtained in this study demonstrated that the addition of sulfur source could increase the content of sulfhydryl protein, and effectively regulate the content of chemical composition, expecially for the sulfhydryl of EPS, and thereby greatly improving the removal efficiency of heavy metals, which showed a great application prospect in the prevention and control of heavy metal pollution.

12932. 题目: Magnetic Biochar Derived from Biosolids via Hydrothermal Carbonization: Enzyme Immobilization, immobilized-enzyme kinetics, environmental toxicity
文章编号: N19092201
期刊: Journal of Hazardous Materials
作者: He Zhang, Anthony G. Hay
更新时间: 2019-09-22
摘要: Magnetic and nonmagnetic biochar (MBC & BC) were produced from biosolids under hydrothermal conditions and characterized in order to understand surface chemistry impacts on enzyme immobilization and activity. Peak surface pore size of MBC was 180 nm and that of BC was 17 nm. Despite similar surface area (≈ 49 m2/g) MBC immobilized more laccase (99 mg/g) than biochar (31 mg/g). For horseradish peroxidase (HRP), the two biochars had similar immobilization capacity (≈ 65 mg/g). Laccase and HRP on MBC had 47.1 and 18.0% higher specific activity than on BC, respectively. The matrix activity of MBC-laccase (33.3 U/mg support) was 3.7-fold higher than BC-laccase (8.8 U/mg support) and higher than the same amount of free laccase (30.2 U) at pH 3.0 (P < 0.05). Although MBC had its own peroxide oxidation activity (104.1 and 165.9 U/mg biochar at pHs 5&6) this only accounted for 16.7 and 20.4 % of the total MBC-HRP activity respectively. After 10 wash cycles, MBC still retained 79.3% and 60.3% of laccase and HRP activity, respectively. Additionally, MBC had lower acute toxicity, suggesting that it is relative benign from an environmental perspective.
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12933. 题目: Photodegradation of Fludioxonil and Other Pyrroles: The Importance of Indirect Photodegradation for Understanding Environmental Fate and Photoproduct Formation
文章编号: N19092106
期刊: Environmental Science & Technology
作者: Jennifer N Apell, Nicholas C. Pflug, Kristopher McNeill
更新时间: 2019-09-21
摘要: Fludioxonil is a pyrrole-containing pesticide whose registration as a plant protection product is currently under review in the United States and Europe. There are concerns over its potential persistence and toxicity in the aquatic environment; however, the pyrrole moiety represents a potential reaction site for indirect photodegradation. In this study, the direct and indirect photodegradation of fludioxonil, along with pyrrole, 3-cyanopyrrole, and 3-phenylpyrrole, were investigated. Results showed that pyrrole moieties are capable of undergoing direct photoionization and sensitized photooxidation to form radical cation species, which then likely deprotonate and react with dissolved oxygen. Additionally, pyrrole moieties can undergo reactions with singlet oxygen (1O2). Furthermore, the presence of electron-withdrawing or -donating substituents substantially impacted the reaction rate with 1O2 as well as the one-electron oxidation potential of the pyrrole that dictates reactions with triplet states of dissolved organic matter (3CDOM*). For fludioxonil, which can undergo both direct and indirect photodegradation, the reaction rate constant with 1O2 alone resulted in a predicted t1/2 < 2 days in waters under sunlit near-surface conditions, suggesting it will not be persistent in aquatic systems. These results are useful for evaluating the environmental fate of fludioxonil as well as other pyrrole compounds.

12934. 题目: Spectral characteristics of soil dissolved organic matter: Long-term effects of exogenous organic matter on soil organic matter and spatial-temporal changes
文章编号: N19092105
期刊: Chemosphere
作者: N.Y. Musadji, L. Lemée, L. Caner, G. Porel, P. Poinot, C. Geffroy-Rodier
更新时间: 2019-09-21
摘要: The aim of this study was to evaluate the long-term effect of urban and green waste compost exogenous organic matter (EOM) on soil dissolved organic matter (DOM). A luvic cambisol was amended 7 years before the study. DOM was investigated along a soil profile down to 1 m depth regarding seasonal variations (autumn and spring). DOM sampled by suction cups was characterized using dissolved organic carbon (DOC) content and excitation emission matrix (EEM) fluorescence. The variability of DOM concentrations was pronounced but no major change in composition was determined. The results obtained, reinforced by statistical analysis, showed that the DOM quality was mainly influenced by soil management (organic matter amendment) whereas the quantity mainly depended on the season (heavy precipitation event). DOM humic characteristics were strongly dependent on amendment and changed with depth but was not affected by the season. Long term effect of compost organic matter was highlighted after a 7-years amendment.

12935. 题目: Competitive adsorption of tylosin, sulfamethoxazole and Cu(II) on nano-hydroxyapatitemodified biochar in water
文章编号: N19092104
期刊: Chemosphere
作者: Zhen Li, Zhaoyan Wang, Xiaona Wu, Miao Li, Xiang Liu
更新时间: 2019-09-21
摘要: Antibiotics and heavy metals are frequently detected simultaneously in water environment. In this study, the competitive adsorption behavior of tylosin (TYL) and sulfamethoxazole (SMX) on nano-hydroxyapatite modified biochar (nHAP@biochar) in accordance with Cu(II) in single, binary and ternary systems was investigated. The specific surface area of nHAP@biochar was 566.056 m2/g. The adsorption of TYL on nHAP@biochar reduced by 13.36%–41.04% or 9.92%–38.69% with Cu(II) and SMX in the solution, respectively. The suppression of SMX was stronger than Cu(II) on the adsorption of TYL when the SMX or Cu(II) was constant. The adsorption of SMX increased by 2.01–3.56 times in the present of Cu(II), while suppressed by TYL up to 42.30%. Due to the bridging of TYL or SMX between the nHAP@biochar and Cu(II) and destroying of bound water surrounded, the adsorption of Cu(II) increased to a greater extent. Electrostatic interaction and H-bond were the two main interactions between TYL, SMX and Cu(II) and nHAP@biochar. π-π interactions was also interaction between the SMX and nHAP@biochar.

12936. 题目: Effects of pH and gallic acid on the adsorption of two ionizable organic contaminants to rice straw-derived biochar-amended soils
文章编号: N19092103
期刊: Ecotoxicology and Environmental Safety
作者: Ying He, Ting Yao, Shuo Tan, Bingqi Yu, Kailin Liu, Lifeng Hu, Kun Luo, Min Liu, Xiangying Liu, Lianyang Bai
更新时间: 2019-09-21
摘要: The existing form of ionizable organic contaminants (IOCs) could affect their adsorption characteristics to soil and biochar. In this study, 2 IOCs, namely, sulfadiazine and imazalil, were selected to study their adsorption by rice straw-derived biochar-amended soils, as well as the effect of pH and gallic acid on their adsorption. The results showed that the soil adsorption isotherms of the two ionizable organic contaminants could be fitted well by a linear equation and the Freundlich equation, and r2 was more than 0.80. The adsorption coefficient (Kd) in the three kinds of soil ranged from 0.262 to 4.07 L kg−1 for sulfadiazine and from 3.11 to 96.5 L kg−1 for imazalil. After the addition of biochar, the adsorption of sulfadiazine and imazalil in the soil increased. The adsorption of sulfadiazine by biochar gradually decreased with the increase in pH; the adsorption of imazalil increased when the pH increased from 2 to 5 and then gradually decreased with increasing pH. Gallic acid enhanced the adsorption of the two IOCs to pure soil and biochar-amended soil.

12937. 题目: Binding characteristics of cadmium and zinc onto soil organic matter in different water managements and rhizosphere environments
文章编号: N19092102
期刊: Ecotoxicology and Environmental Safety
作者: Jiajun Wen, Zhongwu Li, Ninglin Luo, Mei Huang, Xiang Ding, Xianrong Bu, Ming Chen
更新时间: 2019-09-21
摘要: Soil organic matter (SOM) could immobilize most of metals, but it could promote the migration of a small part of metals in special environments. Heavy rainfall and drought makes wetlands affected by the alternation of drought and flood, altering the mobility of metals. Few studies have been conducted on the changes of binding characteristics of metals onto SOM which derived from different water conditions and rhizospheric environments. The objective of this paper was to explore the sequential differences of spectral variations of fluorescent groups and UV–Vis groups of metals onto SOM which derived from different water managements and rhizospheric environments. The method adopted was mainly two-dimensional correlation analysis (2DCOS). The results showed that flooding samples contained more aromatic substances compared to draining samples, which could promote metal binding. The binding characteristics were shown in the following: (1) Cd2+ and Zn2+ could react with aromatic substances, react with functional groups in SOM, and promote the formation of new groups such as carboxyl; (2) both Zn2+ and Cd2+ could bind with functional groups on proteins but relatively reductive environment can weaken the binding ability of Cd2+; (3) the protein-like or fulvic-like groups gave the fastest responses and then came the amide and carboxyl groups in nearly all flooding samples; (4) in flooding samples, Cd2+ was most easily to bind with fulvic-like groups, while Zn2+ was most easily to bind with protein-like groups. This work is conducive to the long-term management of heavy metal pollutants in wetlands.
图文摘要:

12938. 题目: Are the n-alkane carbon isotopic profiles of South Australian coastal asphaltites indicative of their extent of weathering?
文章编号: N19092101
期刊: Organic Geochemistry
作者: David M. McKirdy, Se Gong, Alexander J. Corrick, P. Anthony Hall, Christine Trefry, Andrew S. Ross
更新时间: 2019-09-21
摘要: Asphaltic bitumen (asphaltite) found on the ocean beaches of South Australia is considered to be a product of an adjacent, but as yet unlocated, submarine oil seep. Four large asphaltites recently stranded on three different beaches were sub-sampled (n = 5–6). Samples were analysed to determine if their n-alkane δ13C profiles displayed systematic variation along a transect from the centre to the outer rim of the specimen. Previously reported 13C-enrichment in n-alkanes isolated from the outer portions of similar archival asphaltites was attributed to weathering. With one notable exception, these new specimens exhibited no unidirectional enrichment from interior (fresh) to exterior (weathered), although in every instance n-alkanes in the intermediate and outermost sub-samples were for the most part isotopically heavier than the same homologues in the central interior of the specimen. To be a viable measure of the extent of weathering in a population of coastal asphaltites, and hence also their relative exposure time in the ocean, this analytical protocol requires the specimens to have remained physically intact during their transit from the parent seep to shore. Whether this requirement has been met is impossible to determine, thereby limiting the effectiveness of the method to those specimens in which there is a consistent pattern of internal variation in their n-alkane carbon isotope profiles.

12939. 题目: Exploring the upper particle size limit for field flow fractionation online with ICP-MS to address the challenges of water samples from the Taihu Lake
文章编号: N19092011
期刊: Analytica Chimica Acta
作者: Jingjing Yang, Ping Tan, Tianyin Huang, Volker Nischwitz
更新时间: 2019-09-20
摘要: Regular algal blooms are occurring in Taihu lake, which may be triggered by resuspension of sediments containing relevant amounts of phosphorus. Therefore, our study aims at quantification of phosphorus concentrations bound to suspended particulate matter in Taihu water samples to investigate this hypothesis. A field flow fractionation (FFF) method online with ICP-MS detection was developed to achieve an overview on particulate fractions of phosphorus and related elements including Fe, Al and C from the low nanometer to the low micrometer size range. Mass balance of dissolved and particulate elemental contents was established for quality control purpose and indicated low recovery of Fe, Al and P. Complementary determination of volume based particle size distribution by dynamic imaging analysis showed a majority of particle volume and thus mass in particles with size >5 μm. In order to address this challenge, the upper particle size limit of FFF online with ICP-MS was for the first time investigated in detail using well characterised monodisperse latex particles as model for organic matter in the low micrometer size range including microalgae. The effect of pre-filtration of the sample as well as the contribution of sample introduction via three different interfaces including micromist nebuliser/spray chamber, direct injection nebulisation and APEX with heated spray chamber and solvent removal by condensation on the particulate carbon recovery was studied by ICP-MS detection. The same instrumental setup was also applied for the characterisation of particulate elemental contents in the Taihu water samples as far as possible. Significant improvement of the detected particulate fraction in Taihu water samples was achieved by increasing the membrane pore size for pre-filtration and by using the APEX for introduction of the eluate from FFF into ICP-MS.

12940. 题目: Linkages between flow regime, biota, and ecosystem processes: Implications for river restoration
文章编号: N19092010
期刊: Science
作者: Margaret Palmer, Albert Ruhi
更新时间: 2019-09-20
摘要: River ecosystems are highly biodiverse, influence global biogeochemical cycles, and provide valued services. However, humans are increasingly degrading fluvial ecosystems by altering their streamflows. Effective river restoration requires advancing our mechanistic understanding of how flow regimes affect biota and ecosystem processes. Here, we review emerging advances in hydroecology relevant to this goal. Spatiotemporal variation in flow exerts direct and indirect control on the composition, structure, and dynamics of communities at local to regional scales. Streamflows also influence ecosystem processes, such as nutrient uptake and transformation, organic matter processing, and ecosystem metabolism. We are deepening our understanding of how biological processes, not just static patterns, affect and are affected by stream ecosystem processes. However, research on this nexus of flow-biota-ecosystem processes is at an early stage. We illustrate this frontier with evidence from highly altered regulated rivers and urban streams. We also identify research challenges that should be prioritized to advance process-based river restoration.

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