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24641. 题目: Bioaccumulation kinetics and tissue distribution of silver nanoparticles in zebrafish: The mechanisms and influence of natural organic matter
文章编号: N20031408
期刊: Ecotoxicology and Environmental Safety
作者: Bowen Xiao, Xiaolei Wang, Jing Yang, Kunkun Wang, Yinqing Zhang, Binbin Sun, Tong Zhang, Lingyan Zhu
更新时间: 2020-03-14
摘要: The wide application of silver nanoparticles (AgNPs) has inevitably led to their release into the natural aquatic environment. Natural organic matter (NOM) is ubiquitous and would influence the fate and effects of these nanoparticles in such aquatic environments. Here we demonstrate that NOM plays an important role in the bioaccumulation kinetics and tissue distribution of AgNPs in zebrafish. In the presence of humic acid and fulvic acid, the uptake rates of AgNPs decreased while the depuration rates of AgNPs increased. As a result, the bioconcentration factor (BCF) of AgNPs in the entire body of the zebrafish was reduced. AgNPs were mainly taken up by the zebrafish via oral ingestion and were greatly accumulated in the liver, intestine and gill. In the intestine, NOM effectively inhibited the AgNPs from penetrating the cell membranes into internal tissues and also suppressed the disintegration and dissolution of AgNPs in gastrointestinal fluid, thereby decreasing the absorption of Ag by zebrafish. This research underlines the significance of incorporating the effects of NOM into predictive models for accurately assessing the toxicity and ecological risks of nanoparticles in natural aquatic environments.

24642. 题目: Aggregate formation and organo-mineral association affect characteristics of soil organic matter across soil horizons and parent materials in temperate broadleaf forest
文章编号: N20031407
期刊: Biogeochemistry
作者: S. Vormstein, M. Kaiser, H.-P. Piepho, B. Ludwig
更新时间: 2020-03-14
摘要: Precise assessment of soil organic carbon (OC) storage requires understanding of soil type and depth specific differences in organic matter (OM) stabilization. Therefore, we aimed to analyze OC dynamics down the soil profile and to clarify the effect of depth on the importance of aggregate formation and mineral adsorption for OC storage in mature beech forest soils developed from different parent materials. Aggregate size and density fractions were separated from samples of top and subsoil horizons, which were quantified and analyzed by infrared spectroscopy. We also determined the microbial biomass C (Cmic) and the amount of C decomposed within incubation experiments (CO2-C) for the bulk soil samples. OC stabilized via aggregate formation and mineral association significantly increased with soil depth. However, this stabilized pool seemed to fuel the labile OM stronger in the subsoil than in the topsoil because the CO2-C/SOC and CO2-C/Cmic ratios increased with depth. Measured differences in the magnitude of the detected stabilization and destabilization patterns were attributed to parent material and soil horizon, indicating pronounced spatial and vertical heterogeneity in the contribution of soils under temperate broadleaf forest to terrestrial C sequestration. Considering such site and depth specific differences will improve assessment and modelling of soil OC storage for areas covered with the same forest type but with high pedogenetic diversity.

24643. 题目: Grazing significantly increases root shoot ratio but decreases soil organic carbon in Qinghai‐Tibetan Plateau grasslands: a hierarchical meta‐analysis
文章编号: N20031406
期刊: Land Degradation & Development
作者: Liang Yan, Yong Li, Li Wang, Xiaodong Zhang, Jinzhi Wang, Haidong Wu, Zhongqing Yan, Kerou Zhang, Xiaoming Kang
更新时间: 2020-03-14
摘要: The Qinghai‐Tibetan Plateau (QTP) is the most expansive area of alpine grasslands worldwide, which have been grazed for thousands of years. Distinct environmental conditions render QTP grasslands vulnerable to disturbances. Intensified grazing in the area has led to its degradation in recent decades. However, the effects of grazing on grassland production, soil carbon, and nitrogen contents, their relationships and the factors influencing the grasslands of QTP have yet to be determined. In this study, we evaluated the effect of grazing by using a hierarchical meta‐analysis, and explored relation of response variables by structural equation modeling. In all, grazing significantly decreased the aboveground biomass (−38%), total biomass (−14%), litter (−63%), soil organic carbon (−20%) and total nitrogen (−15%). The root shoot ratio was increased (75%). Grazing intensity exerted significant effects, and mean annual temperature and altitude influenced the responses to a certain degree. Specifically, the response of the root shoot ratio, which can affect the responses of soil organic carbon and total nitrogen, was significantly higher in the QTP grasslands. Our findings elucidated the response patterns, specialties, relationships, and factors influencing the QTP grasslands, which need to be considered in the development of process‐based models and the sustainable use of alpine grasslands on QTP in the future. This article is protected by copyright. All rights reserved.

24644. 题目: The soluble fraction from straw-derived biochar supplies nutrients and affects carbon storage of coastal mudflat soil in rice paddy
文章编号: N20031405
期刊: Environmental Science and Pollution Research
作者: Jining Zhang, Sheng Zhou, Huifeng Sun, Fan Lü, Pinjing He
更新时间: 2020-03-14
摘要: Incorporation of biochar into soil has been proposed as a strategy for enhancing soil fertility and rice production. A pot trial was carried out to investigate the effects of the dissolvable fraction of biochar in the Yangtze River estuary, China. Soil in plastic pots was incorporated with straw biochar at five different rates: 0%, 5%, 10%, 15%, and 20% (w/wet weight). The rice height, tiller number, and grain yield were recorded; soils and surface water were sampled, and key chemical properties were investigated. Rice grain yield was improved by 29.1–34.2%, and the grain-to-straw ratio was promoted by 8.0–26.1% in the treatments with 10–15% biochar incorporated compared with the control. Soil total organic carbon and total nitrogen contents increased 65.7–242.8% and 22.9–75.3% in the biochar-amended treatments, respectively. Meanwhile, the soil dissolved organic carbon contents increased by 13.4–25.3% in biochar-amended treatments. Higher amounts of added biochar resulted in increased soil electrical conductivity but had no significant effect on soil pH. The major anion was Cl−, and the main cations were K+ and Na+ in the mudflat soil. Addition of 10–15% straw biochar to soil for agronomic purposes is a potentially sustainable ecologically technology.

24645. 题目: On the fate of oxygenated organic molecules in atmospheric aerosol particles
文章编号: N20031404
期刊: Science Advances
作者: V. Pospisilova, F. D. Lopez-Hilfiker, D. M. Bell, I. El Haddad, C. Mohr, W. Huang, L. Heikkinen, M. Xiao, J. Dommen, A. S. H. Prevot, U. Baltensperger, J. G. Slowik
更新时间: 2020-03-14
摘要: Highly oxygenated organic molecules (HOMs) are formed from the oxidation of biogenic and anthropogenic gases and affect Earth’s climate and air quality by their key role in particle formation and growth. While the formation of these molecules in the gas phase has been extensively studied, the complexity of organic aerosol (OA) and lack of suitable measurement techniques have hindered the investigation of their fate post-condensation, although further reactions have been proposed. We report here novel real-time measurements of these species in the particle phase, achieved using our recently developed extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF). Our results reveal that condensed-phase reactions rapidly alter OA composition and the contribution of HOMs to the particle mass. In consequence, the atmospheric fate of HOMs cannot be described solely in terms of volatility, but particle-phase reactions must be considered to describe HOM effects on the overall particle life cycle and global carbon budget.

24646. 题目: Recalcitrant dissolved organic nitrogen formation in thermal hydrolysis pretreatment of municipal sludge
文章编号: N20031403
期刊: Environment International
作者: Dian Zhang, Yiming Feng, Haibo Huang, Wendell Khunjar, Zhi-Wu Wang
更新时间: 2020-03-14
摘要: Thermal hydrolysis pretreatment (THP) has been considered as an advanced approach to enhance the performance of anaerobic digestion treating municipal sludge. However, several drawbacks were also identified with THP including the formation of brown and ultraviolet-quenching compounds that contain recalcitrant dissolved organic nitrogen (rDON). Melanoidins produced from the Maillard reaction between reducing sugar and amino group have been regarded as a representative of such compounds. This review presented the state-of-the-art understanding of the mechanism of melanoidin formation derived from the research of sludge THP, food processing, and model Maillard reaction systems. Special attentions were paid to factors affecting melanoidin formation and their implications to the control of rDON in the sludge THP process. These factors include reactant availability, heating temperature and time, pH, and the presence of metallic ions. It was concluded that efforts need to be focused on elucidating the extent of the Maillard reaction in sludge THP. This paper aims to provide a mechanistic recommendation on the research and control of the THP-resulted rDON in municipal wastewater treatment plants.

24647. 题目: Meteorological phenomenon as a key factor controlling variability of labile particulate mercury in rivers and its inflow into coastal zone of the sea
文章编号: N20031402
期刊: Environmental Research
作者: Karolina Gębka, Magdalena Bełdowska, Dominika Saniewska, Ewa Korejwo, Michał Saniewski
更新时间: 2020-03-14
摘要: Mercury (Hg) is recognized as a global pollutant, which can be transported to the sea by suspended particulate matter (SPM) via rivers constituting the main source of mercury in the southern Baltic sea. The aim of the present study was to characterize the mercury fractions in suspended particulate matter, as well as the transformations of Hg during its riverine transportation into the sea. The thermo-desorption method was used to determine the labile and stable mercury fractions in SPM of rivers (Reda, Zagórska Struga, Gizdepka, Płutnica) within the Baltic Sea basin. In this paper six periods were designated (heating, non-heating, drought, rains, downpour/flood and thaws), during which the river suspended particulate matter was enriched with various fractions of mercury. Meteorological and hydrological phenomena such as downpours and thaws intensified surface runoff, causing an increase in the share of Hgabs and Hgads1 mercury fractions in suspended particulate matter. Whereas, droughts contributed to the formation of HgS in a large river and to an inflow of adsorbed Hg in smaller rivers decrease of air temperature leads to increase of fossil fuel combustion and then increases the share of adsorbed Hg (mainly bound with halides) in riverine particulate matter. In the non-heating season, the main fraction was the mercury absorbed inside organic matter.

24648. 题目: Organic Amines Enhance the Formation of Iodinated Trihalomethanes during Chlorination of Iodide-Containing Waters
文章编号: N20031401
期刊: Environmental Science & Technology
作者: Yan Wang, Huiyu Dong, Zhengdi Wu, Zhimin Qiang
更新时间: 2020-03-14
摘要: The effects of organic amines (OAs) including glycine (Gly), sarcosine (Sar), and triethanolamine (Tea), representing primary, secondary, and tertiary amines, respectively, on iodinated trihalomethanes (I-THMs) formation during chlorination of iodide (I–)-containing waters were investigated. The total concentration of I-THMs formed in the co-presence of an OA and natural organic matter (NOM) was more than 3 times the sum of those formed in the presence of an OA alone and NOM alone, as OAs competed for free chlorine (FC) to form organic chloramines. Taking Gly as an example, the transformation of I– was determined. In the absence of NOM, the yields of iodate (IO3–) were 89%, 60%, and nearly 0 at [Gly]o/[FC]o = 0:1, 3:4, and 1:1, but 0, 2%, and 43% for hypoiodous acid (HOI), respectively. In the presence of NOM, as [Gly]o/[FC]o increased from 0:1 to 1:1, the yield of IO3– decreased from 66% to 0, while that of I-THMs increased from 2.9% to 16.1%. The competition of FC by OAs inhibited the oxidation of HOI to IO3–, and the formed organic chloramines can oxidize I– to HOI, thus promoting I-DBPs formation. Finally, the enhanced I-THMs formation was verified in real waters.

24649. 题目: Biochar supported CuO composites used as an efficient peroxymonosulfate activator for highly saline organic wastewater treatment
文章编号: N20031311
期刊: Science of The Total Environment
作者: Zhendong Li, Dongfang Liu, Wenli Huang, Xiaocheng Wei, Weiwei Huang
更新时间: 2020-03-13
摘要: Biochar supported copper oxide composite (BC-CuO) was synthesized and attempted to activate peroxymonosulfate (PMS) for treating highly saline (100–400 mM) wastewater. In the BC-CuO/PMS system, rapid removals of Methylene Blue (MB), Acid Orange 7, Rhodamine B, Atrazine and Ciprofloxacin from the highly saline system were observed within 30 min, attaining a high efficiency of 99.68%, 100%, 100%, 100% and 78.27%, respectively. Meanwhile, the BC-CuO/PMS can remove >88.61% of MB in other salt systems containing one or more salt components and 68.43% of COD from landfill leachate. Experimental results confirmed that sulfate radical (SO4▪-), hydroxyl radical (▪OH) and singlet oxygen (1O2) all contributed to the pollutants degradation, but 1O2 was dominated in highly saline systems. On the basis of the characterization and analysis data, possible activation mechanisms of the oxygenated functional groups of biochar and hydroxylation of CuO surface accelerating the generation of 1O2 were proposed. BC-CuO activating PMS is a promising technique for the removal of organic pollutants from highly saline wastewater or complex background.

24650. 题目: Neutral monosaccharides and their relationship to metal contamination in mangrove sediments
文章编号: N20031310
期刊: Chemosphere
作者: Dandan Duan, Wenlu Lan, Fengyuan Chen, Pei Lei, Hao Zhang, Jie Ma, Yang Wei, Ke Pan
更新时间: 2020-03-13
摘要: Mangrove sediments act as an important natural sink and a secondary source for trace metals. The main objective of this study was to investigate metal contamination and its relationship to mangrove-derived carbohydrates in mangrove sediments. Sixteen metals (Be, V, Cr, Co, Ni, Cu, Zn, Ga, As, Sr, Cd, Sn, Sb, Ba, Tl, and Pb)were analyzed in the surface sediments from four sites at different latitudes on the southeast coastline of China. The sedimentary organic matter was characterized by Rock-Eval pyrolysis, and the neutral sugars were examined by gas chromatograph mass spectrometry. Our results from the enrichment factors indicated that the mangrove sediments were no enriched by Ga, Sr, and Ba, minor enriched by Be, V, Cr, Co, Ni, Cu, Zn, As, Sn, Sb, Tl, and Pb, and moderate enriched by Cd. Litterfall was a major source of organic matter in the mangrove sediments, and the neutral sugars were mainly derived from this litterfall. Significant correlations were detected between the total organic carbon, pyrolytic parameters, neutral sugars, and enrichment factors of V, Cr, Co, Ni, Zn, and Cd, suggesting the input of neutral carbohydrates played an important role in enhancing the metal accumulation in the mangrove sediments. The mangrove litterfall itself was a major source of metals for the sediments, and the mangrove-derived organic matter enhanced the sediment's metal accumulation.

24651. 题目: Microbial community composition, co-occurrence network pattern and nitrogen transformation genera response to biochar addition in cattle manure-maize straw composting
文章编号: N20031309
期刊: Science of The Total Environment
作者: Ayodeji Bello, Yue Han, Haifeng Zhu, Liting Deng, Wei Yang, Qingxin Meng, Yu Sun, Ugochi Uzoamaka Egbeagu, Siyuan Sheng, Xiaotong Wu, Xin Jiang, Xiuhong Xu
更新时间: 2020-03-13
摘要: A better understanding of the microbial group influencing nitrogen (N) dynamics and cycling in composting matrix is critical in achieving good management to alleviate N loss and improve final compost quality. This study investigated the bacterial composition, structure, co-occurrence network patterns and topological roles of N transformation in cattle manure-maize straw composting using high-throughput sequencing. The two treatments used in this experiment were cattle manure and maize straw mixture (CM) and CM with 10% biochar addition (CMB). In both treatments, the bacterial community composition varied during composting and the major phyla included Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes and Chloroflexi. The phyla Actinobacteria and Proteobacteria were more abundant in CMB treatment while Firmicutes was abundant in CM piles. The metabolic functional profiles of bacteria was predicted using the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) which revealed that except for cellular processes pathway, CMB had slight higher abundance in metabolism, genetic information processing and environmental information processing than the CM. Pearson correlation revealed more significant relationship between the important bacteria communities and N transformation in CMB piles compared with CM. Furthermore, network pattern analysis revealed that the bacterial networks in biochar amended piles are more complex and harbored more positive links than that of no biochar piles. Corresponding agreement of multivariate analyses (correlation heatmap, stepwise regression, Path and network analyses) revealed that Psychrobacter, Thermopolyspora and Thermobifida in CM while Corynebacterium_1, Thermomonospora and Streptomyces in CMB were key bacterial genera affecting NH4+-N, NO3−-N and total nitrogen (TN) transformation respectively during composting process. These results provide insight into nitrogen transformation and co-occurrence patterns mediating microbes and bacterial metabolism which could be useful in enhancing compost quality and mitigating N loss during composting.

24652. 题目: Incorporation of Cochlodinium bloom-derived organic matter into a temperate subtidal macrobenthic food web as traced by stable isotopes
文章编号: N20031308
期刊: Marine Pollution Bulletin
作者: Hyun Je Park, Jung Hyun Kwak, Hee Yoon Kang, Kee-Young Kwon, Weolae Lim, Chang-Keun Kang
更新时间: 2020-03-13
摘要: Harmful algal blooms involving the dinoflagellate Cochlodinium polykrikoides occur every summer off the Korean peninsula's central southern coast. To determine whether Cochlodinium bloom-derived organic carbon is incorporated into the subtidal macrobenthic food web, we compared the δ13C and δ15N values of suspended particulate organic matter (SPOM) and sedimentary organic matter, and macrobenthic consumers between bloom and non-bloom seasons. Chemotaxonomic analysis revealed the presence of Cochlodinium blooms in summer and a predominance of diatoms in autumn. Both the δ13C and δ15N values of SPOM were higher in the bloom than in the non-bloom seasons. Such temporal shifts in the δ13C and δ15N values were also observed for most macrobenthic consumers collected in both seasons. Consistent temporal isotopic shifts in SPOM and macrobenthos revealed that the Cochlodinium bloom-derived carbon was incorporated into the coastal benthic food web, resulting from its increasing availability during blooms.

24653. 题目: Does soil organic carbon quality or quantity govern relative temperature sensitivity in soil aggregates?
文章编号: N20031307
期刊: Biogeochemistry
作者: Madhuri Wankhede, Avijit Ghosh, M. C. Manna, Sukanya Misra, P. Sirothia, Mohammad Mahmudur Rahman, Pratap Bhattacharyya, M. Singh, Ranjan Bhattacharyya, A. K. Patra
更新时间: 2020-03-13
摘要: Soil aggregates govern soil organic carbon (SOC) sequestration. But, sparse understanding about the process leads to inaccuracy in predicting potential of soil to stabilize C in warming world. We appraised effects of 43 years of fertilization on relative temperature sensitivity of SOC decomposition (Q10) in soil aggregates to know whether SOC quality or quantity governs Q10. Treatments were: fallow, control, 100% recommended dose of nitrogen (N), N and phosphorus (NP), N, P and potassium (NPK), and NPK + farmyard manure (FYM) (NPK + FYM). Macroaggregates, microaggregates and silt + clay (s + c) fractions were incubated for 16 weeks at 25, 35 and 45 °C, SOC quality (R0) and Q10 were computed. SOC mineralization from macro- and micro- aggregates were 34 and 28% higher than s + c across the treatments. The s + c fraction of NPK + FYM had ~ 41, 40 and 24% higher C decay rate than NPK plots at 25, 35 and 45 °C, respectively. For s + c fraction Q10 increased over other aggregates. Mean Q10 of s + c fraction was ~ 18.3 and 17.5% higher than macro and micro-aggregate-C, respectively. R0 was the lowest for NPK + FYM, suggesting long-term manuring with balanced NPK significantly enhance recalcitrance of C. We observed Q10 of macroaggregates and s + c fraction is controlled by C quality but C quantity governs Q10 of microaggregates in Vertisol. Specifically, microaggregates of NPK + FYM were more temperature sensitive, and could be vulnerable to C loss. Hence, practices facilitating microaggregate formation should be avoided. Thus, we recommend manure application for facilitating C sequestration.

24654. 题目: Effect of the soil biochar aging on the sorption and desorption of Pb2+ under competition of Zn2+ in a sandy calcareous soil
文章编号: N20031306
期刊: Environmental Earth Sciences
作者: Sadegh Raeisi, Hamidreza Motaghian, Ali Reza Hosseinpur
更新时间: 2020-03-13
摘要: Applying biochar in contaminated soils can reduce the availability of the heavy metals (HMs). However, there is no sufficient evidence regarding the effects of biochar on adsorption and desorption of lead (Pb2+) in the calcareous soils. Thus, the present study aimed to investigate the effect of walnut leaf biochars (1% w/w) produced at different temperatures (200 (B200), 400 (B400), and 600 (B600) °C) on the adsorption and desorption properties of Pb2+ in individual (Pb) and competitive (Pb + Zn) systems at two incubation times (30 and 90 days). The results showed that the maximum adsorption capacity of Pb2+ (qm) in the soils treated with B400 and B600 was higher than the soils treated with feedstock and B200. In the presence of Zn2+, the qm value decreased. Strength of adsorption (KL) increased with an increment in the pyrolysis temperature, and was lower in competitive system than the individual system in all treatments. Also, the KL was lower in competitive system than the individual system in all treatments. Strength of Pb2+ adsorption in soils treated with B400 and B600 enhanced at 90 days compared to 30 days of incubation. Lead desorbed in 10 mM CaCl2 (< 1% of adsorbed Pb2+) and DTPA–TEA solutions decreased with an increase in the pyrolysis temperature. The results revealed that walnut leaf biochars produced at high temperatures had a higher capacity and strength of Pb2+ adsorption, while lowering Pb2+ desorption compared with other biochars. The results of this study revealed that walnut leaf biochars produced at high temperatures could adsorb and immobilize Pb2+ in sandy calcareous soils at either individual or competitive systems.

24655. 题目: Lean and keen: microbial activity in soils from the Maritime Antarctic
文章编号: N20031305
期刊: European Journal of Soil Science
作者: D. W. Hopkins, P. G. Dennis, S. P. Rushton, K. K. Newsham, A. G. O'Donnell
更新时间: 2020-03-13
摘要: The soils of the Maritime and sub‐Antarctic experience extreme environmental conditions but nonetheless host biological communities which can survive low temperatures, limited water availability and short‐day lengths or even the complete absence of solar radiation during the winter. We determined the organic carbon (SOC) and total N, soil microbial biomass (SMB), labile carbon (LC) and respiration rate (RR) in soil samples from the longest latitudinal transect (approximately 2000 km) ever sampled exclusively in the Maritime and sub‐Antarctic comprising 69 sites located between South Georgia (54°S) and south‐eastern Alexander Island (72°S). With the exception of the most northerly location (South Georgia), the greatest SMB values occurred at 67–68°S, despite the harsh environmental conditions. This is consistent with the relative nutrient richness of the soils at these latitudes, as indicated by large SOC and total soil N concentrations, which are in turn probably linked to more abundant guano and excreta deposition by sea birds and seals which have fewer and smaller areas of ice‐free terrain to land or haul out on further south. South of 68°S, SOC values declined with increasing latitude, which is probably due to increasingly extreme environmental conditions. We also found that the SOC and SMB values, the proportion of SOC considered labile (LC/SOC) and the carbon mineralization rates expressed as either RR/SOC or RR/SMB were all small compared with values from less extreme temperate and tropical regions. However, the proportion of the SOC in the microbial biomass (SMB/SOC) was substantially greater than that reported for non‐polar soils. We conclude that although the soils of the Maritime and sub‐Antarctic have small and relatively inactive microbial communities, they are characterised by efficient conversion of organic resources into microbial biomass and large affinities for added substrates. This article is protected by copyright. All rights reserved.

24656. 题目: Long-term CO2 enrichment alters the diversity and function of the microbial community in soils with high organic carbon
文章编号: N20031304
期刊: Soil Biology and Biochemistry
作者: Jian Jin, Jen Wood, Ashley Franks, Roger Armstrong, Caixian Tang
更新时间: 2020-03-13
摘要: The response of soil microorganisms to elevated atmospheric CO2 (eCO2) has the potential to alter the regulation of soil biogeochemical processes including carbon and nutrient cycling. A mechanistic understanding of this microbial response in agricultural systems is essential due to the potential impact on soil quality. This study used an eight-year free-air-CO2 enrichment (SoilFACE) experiment to assess the microbial response to eCO2 in three major agricultural soils (Chromosol, Vertosol, and Calcarosol) planted annually with grain crops. Elevated CO2 increased the number of operational taxonomic unit (OTU) by 14.3%, 13.3% and 4.1% and the Shannon diversity by 3.7%, 4.4%, and 2.6% in the top 5-cm soil layer of the Chromosol, Calcarosol and Vertosol, respectively. The relative abundance of the oligotroph Acidobacteriaceae Subgroup 1 in the top 5-cm soil of the Chromosol and Vertosol was significantly increased by eCO2. Elevated CO2 did not affect community diversity in the 5–10 cm soil layer. The functional attribute analysis of the bacterial communities showed that eCO2 increased pectin and benzene degradation, the pentose phosphate pathway and the production of phytase-6 in the top 5-cm soil of the Chromosol. These results suggest that eCO2 increases the presence of oligotrophs in the bacterial community and overall mineralization of soil organic carbon (SOC) in surface soils with high SOC. Changes in microbial function due to eCO2 likely impact the stability of SOC and, consequently, the quality of farming soils for sustainable crop production.

24657. 题目: Phosphorus species in bottom sediments of the Three Gorges Reservoir during low and high water level periods
文章编号: N20031303
期刊: Environmental Science and Pollution Research
作者: Shuai Wang, Wenbo Rao, Jin Qian, Changping Mao, Kun Li
更新时间: 2020-03-13
摘要: Eutrophication and algal blooms have recently been found in the backwater areas of some tributaries in the Three Gorges Reservoir (TGR), for which phosphorus (P) is an important driving factor. However, P species in the TGR sediments at different water levels were little known. In this study, five P species of the TGR sediments during the high and low water level periods were analyzed with a sequential extraction method. The total P (TP) concentrations were 714.88 ± 37.86 μg/g and 697.57 ± 111.49 μg/g at the low and high water levels, respectively. The concentrations of P species decreased in the orders detrital P > authigenic P > organic P > iron-bound P > exchangeable P at the low water level and detrital P > organic P > authigenic P > iron-bound P > exchangeable P at the high water level. P in the TGR sediment sourced mainly from the upstream input at the low water level but from the inputs of tributaries and hillslope soils at the high water level. The bioavailable P (BAP) possessed > 29.5% of total P in the two periods. The total storages of total P and BAP were estimated to be about 1.34 × 106 t and 1.77 × 105 t, respectively during 2003–2017. It was further found that the BAP concentration significantly increased from periods I (2003–2009), II (2010–2014), to III (2015–2017), while the deposition flux and storage of BAP were the highest in period II. Our findings provide new insight into the P cycle and benefit eutrophication treatment in the TGR.

24658. 题目: Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids
文章编号: N20031302
期刊: Science
作者: Olivier Poch, Istiqomah Istiqomah, Eric Quirico, Pierre Beck, Bernard Schmitt, Patrice Theulé, Alexandre Faure, Pierre Hily-Blant, Lydie Bonal, Andrea Raponi, Mauro Ciarniello, Batiste Rousseau, Sandra Potin, Olivier Brissaud, Laurène Flandinet, Gianrico Filacchione, Antoine Pommerol, Nicolas Thomas, David Kappel, Vito Mennella, Lyuba Moroz, Vassilissa Vinogradoff, Gabriele Arnold, Stéphane Erard, Dominique Bockelée-Morvan, Cédric Leyrat, Fabrizio Capaccioni, Maria Cristina De Sanctis, Andrea Longobardo, Francesca Mancarella, Ernesto Palomba, Federico Tosi
更新时间: 2020-03-13
摘要: The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the basis of laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semivolatile ammonium salts are a substantial reservoir of nitrogen in the comet, potentially dominating over refractory organic matter and more volatile species. Similar absorption features appear in the spectra of some asteroids, implying a compositional link between asteroids, comets, and the parent interstellar cloud.

24659. 题目: A Highly Stable Metal–Organic Framework-Engineered FeS 2 /C Nanocatalyst for Heterogeneous Electro-Fenton Treatment: Validation in Wastewater at Mild pH
文章编号: N20031301
期刊: Environmental Science & Technology
作者: Zhihong Ye, José Antonio Padilla, Elena Xuriguera, José L. Beltran, Francisco Alcaide, Enric Brillas, Ignasi Sirés
更新时间: 2020-03-13
摘要: Herein, the novel application of FeS2/C nanocomposite as a highly active, stable, and recyclable catalyst for heterogeneous electro-Fenton (EF) treatment of organic water pollutants is discussed. The simultaneous carbonization and sulfidation of an iron-based metal–organic framework (MOF) yielded well-dispersed pyrite FeS2 nanoparticles of ∼100 nm diameter linked to porous carbon. XPS analysis revealed the presence of doping N atoms. EF treatment with an IrO2/air-diffusion cell ensured the complete removal of the antidepressant fluoxetine spiked into urban wastewater at near-neutral pH after 60 min at 50 mA with 0.4 g L–1 catalyst as optimum dose. The clear enhancement of catalytic activity and stability of the material as compared to natural pyrite was evidenced, as deduced from its characterization before and after use. The final solutions contained <1.5 mg L–1 dissolved iron and became progressively acidified. Fluorescence excitation–emission spectroscopy with parallel factor analysis demonstrated the large mineralization of all wastewater components at 6 h, which was accompanied by a substantial decrease of toxicity. A mechanism with •OH as the dominant oxidant was proposed: FeS2 core–shell nanoparticles served as Fe2+ shuttles for homogeneous Fenton's reaction and provided active sites for the heterogeneous Fenton process, whereas nanoporous carbon allowed minimizing the mass transport limitations.

24660. 题目: Characterization of urban and industrial wastewaters using excitation-emission matrix (EEM) fluorescence: Searching for specific fingerprints
文章编号: N20031225
期刊: Journal of Environmental Management
作者: Francisco J. Rodríguez-Vidal, María García-Valverde, Beatriz Ortega-Azabache, Ángela González-Martínez, Ana Bellido-Fernández
更新时间: 2020-03-12
摘要: Excitation-emission matrix (EEM) fluorescence spectroscopy has been applied to characterize several urban and industrial wastewaters (effluents from different types of industries: brewery, winery, dairy, biscuit, tinned fish industry, slaughterhouse, pulp mill, textile dyeing and landfill leachates), searching for specific fluorescence fingerprints. Tryptophan protein-like peaks (T1 and T2) are the predominant fluorescence in urban and food industry wastewaters (brewery, winery, dairy/milk, biscuit and fish farm industries) but no special fingerprint has been found to discriminate among them. Protein-like fluorescence also dominates the spectra of meat/fish industries (effluents from a tinned fish industry and a slaughterhouse), but in this case tyrosine protein-like peaks (B1 and B2) also appear in the spectra in addition to tryptophan-like peaks. This fact might constitute a specific feature to differentiate these wastewaters from others, since the appearance of peaks B is quite uncommon in wastewaters. The textile dyeing effluent shows a characteristic triple humic-like fluorescence (peaks A, C1 and C2) that may represent a specific fingerprint for this kind of effluent. Leachates from medium-aged and old landfills might also show a specific fingerprint in their EEM spectra: the sole presence of the humic-like peak C with very high fluorescence intensity. This feature also allows differentiating them from young landfill leachates, which show predominance of protein-like peaks. The fluorescence index (FI) does not seem to be very appropriate to characterize wastewaters and its usefulness might be limited to the study of humic substances in natural waters, although further studies are needed on this topic. However, the humification index (HIX) and the biological index (BIX) do seem to be useful for studying wastewaters, since they have provided consistent results in the present work. This study shows the potential of EEM fluorescence to identify the origin of some industrial effluents, although more research is needed to check these preliminary results.