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17721. 题目: Nitrogen isotope constraint on the zonation of multiple transformations between dissolved and particulate organic nitrogen in the Changjiang plume
文章编号: N21111709
期刊: Science of The Total Environment
作者: Xiuli Yan, Jin-Yu Terence Yang, Min Nina Xu, Hongjie Wang, Minhan Dai, Shuh-Ji Kao
更新时间: 2021-11-17
摘要: Information on the sources and transformations of particulate organic N (PN) and dissolved organic N (DON) at the coastal interface remains insufficient due to technological difficulties and complicated features of intensive physical mixing and rapid biological activities. Here, we investigated the spatial distribution of concentrations and isotopic compositions of PN and DON in the Changjiang plume during the summer flood period. In average, DON and PN accounted for 25.6 ± 12.1% and 8.1 ± 9.1% (n = 55), respectively, of the total N pool, with the remaining N primarily in the form of nitrate (NO3−). Mean δ15N values were the lowest for DON (−0.1 ± 2.7‰, n = 58) and slightly higher for PN (2.0 ± 1.6‰, n = 101), and the highest for NO3− (6.5 ± 2.2‰, n = 67), suggesting multiple transformations had occurred to differentiate isotopic characteristics among the three N pools. By applying a conservative mixing model, we found DON deficits (−3.5 ± 3.7 μmol L−1, n = 43) and negative shift in δ15NDON (−3.6 ± 2.2‰, n = 43) in the Changjiang plume, revealing nonconservative DON behaviors. In the offshore surface plume where Chlorophyll a was high, the most likely cause is the DON uptake by phytoplankton with a strong inverse isotope effect (around −40‰). This DON assimilation by phytoplankton contributed to ~16 ± 12% of the PN production, with the remaining supported by NO3− assimilation, producing an overall isotope effect of 4–9‰. However, in waters near the river mouth and at the bottom of the offshore plume where total suspended matter concentrations were high (>5 mg L−1), the DON deficit was most likely induced by the selective adsorption of 15N enriched moieties of DON onto particulate surfaces (with an isotope effect of −20‰ to −5‰). Unlike dissolved organic carbon to behave conservatively in most estuaries, our results show that active transformations had occurred between the DON and PN pools in the Changjiang plume.

17722. 题目: Reducing soil organic carbon mineralization under moderate thinning magnifies the soil carbon sink in a Larix principis-rupprechtii plantation
文章编号: N21111708
期刊: CATENA
作者: Junyong Ma, Yu Han, Shengnan Ji, Bo Liu, Fengchun Lv, Xuan Cai, Jiaqiang Du, Junsheng Li
更新时间: 2021-11-17
摘要: How to reduce the rising carbon (C) in the atmosphere by enhancing forest soil C-holding capacity requires further research. Forest density via thinning has long been studied for this reason. However, how changes in density affect soil C sequestration is still uncertain for many other factors also affect soil C in open forest ecosystems. To measure the effect of thinning on soil organic carbon (SOC) stock relative to other contributing factors, we selected 12 25 × 25 m plots, and applied a series of thinning treatments: CK (control plots; 2173 ± 12 trees ha−1, which was how all plots started), LT (light thinning; 1834 ± 12 trees ha−1), MT (moderate thinning; 1418 ± 7 trees ha−1) and HT (heavy thinning; 1089 ± 13 trees ha−1). We measured the SOC stocks (kg C m−2) for 11 seasons crossing three years. In addition, soils of the four treatment plots (0–50 cm soil depth, 5 layers, 10 cm per layer) were collected once per season, and then the samples were incubated for 56 days before measuring their cumulate mineralized carbon (CMC). The temperature at 10 cm underground was measured every 60 min throughout two years. The active carbon (DOC (dissolved organic C) and MBC (microbial biomass C)) stocks were also measured. We found that soil in MT plots held more C overall, with more active carbon per unit of SOC. Soil temperatures were affected by the thinning as well as the C and N (nitrogen) stock. Soil temperatures and C, N stock alike rose from CK levels and peaked in MT, before decreasing in HT. However, SOC mineralization rate (mineralized-C) was reduced in MT across seasons, and mineralized-C varied seasonally. Soil C and N stocks were enhanced in MT plots, partly due to the increased soil temperatures and the reduced mineralized-C.

17723. 题目: Reinforcing hydration layer on membrane surface via nano-capturing and hydrothermal crosslinking for fouling reduction
文章编号: N21111707
期刊: Journal of Membrane Science
作者: Zhu Xiong, Jiangtao Liu, Yang Yang, Qiaoyun Lai, Xueyan Wu, Jingxin Yang, Qingyi Zeng, Gaosheng Zhang, Shuaifei Zhao
更新时间: 2021-11-17
摘要: Polyvinylidene fluoride (PVDF)@Fe3O4 composite membranes were prepared by phase inversion, followed by crosslinking with hydrophilic silane-based prepolymers. The influences of Fe3O4 nanoparticles (NPs) on morphology, chemistry, hydrophilicity, electric charge and roughness of membrane surfaces were investigated by a number of characterization techniques. The results revealed that the dispersed Fe3O4 nanoparticles reduced the micropores of the composite membrane and maintained the membrane surface roughness. Meanwhile, the dispersed Fe3O4 enabled the membrane to capture more hydrophilic silane-based prepolymers, thereby leading to a robust, dense and zwitterionic characteristic hydration layer on the membrane surface. The reinforced hydration layer imparted the membrane surface with more stable water permeability and higher rejections to humic acid (HA), bovine serum albumin (BSA) and soybean oil during five cycles of cross-flow separation. According to the resistance-in-series model, the anti-oil-fouling mechanism of the membrane relied on manipulating the hydration layer on the membrane surface to prevent the foulants from approaching the membrane surface. The surface-immobilized Fe3O4 facilitated the hydration layer to repel HA and BSA to permeate through the membrane via chelation and adsorption, and then reduced the membrane internal fouling. Our findings provide a new strategy to construct antifouling membrane surfaces by properly tailoring the strength and thickness of the surface hydration layer.

17724. 题目: The effect of the 2020 COVID-19 lockdown on atmospheric black carbon levels in northeastern Greenland
文章编号: N21111706
期刊: Atmospheric Environment
作者: Daniel Charles Thomas, Jesper H. Christensen, Andreas Massling, Jakob Boyd Pernov, Henrik Skov
更新时间: 2021-11-17
摘要: The outbreak of SARS-CoV-2 and subsequent spread of the disease COVID-19 became classified as a pandemic in March of 2020, leading to global safety measures introduced to limit the impact of the virus. This combination of safety measures has become commonly referred to as “lockdown”. The associated industry and lifestyle changes led to reductions in the anthropogenic emission of atmospheric pollutants such as black carbon (BC), which is transported from the mid-latitudes into the Arctic during the winter and spring. Measurements of BC and other anthropogenic pollutants are of increasing importance in the Arctic due to the rapid warming observed there in the past few decades. It is believed that BC has a significant role in this warming, and so understanding the Arctic's response to reduced BC emissions at lower latitudes will provide insight into how future changes might mitigate further warming. Reductions in BC have been reported worldwide, and so in this study, the impact of these reductions on BC concentrations at the High Arctic site Villum Research Station was investigated. The effect was examined from March 2020, around when global lockdowns began, to June 2020, when the Arctic haze period ended and BC levels were once again low. Firstly, the Danish Eulerian Hemispheric Model (DEHM) was used to assess this impact on BC concentrations by adjusting global anthropogenic pollution emission inventories to simulate those observed during the lockdown period and comparing the results to a similar model run with standard emission inventories. Secondly, equivalent BC data from an aethalometer at Villum Research Station were analysed, comparing the concentrations during the lockdown period to both aethalometer data from previous years and DEHM results from the lockdown period. It was found that when adjusted DEHM emission inventories were introduced from the 1st of March, the model predicted a reduction in BC concentrations beginning on the 10th of March and reached a 10% reduction by the 1st of April. This reduction fluctuated around 10% until the end of the Arctic haze period. Aethalometer data did not show any significant change from previous years, and no concentration reduction could be concluded from its comparison with DEHM results. This is likely because the predicted reduction of 10% is smaller than both the inter-annual and intra-annual variability of measured BC concentrations at Villum.

17725. 题目: Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments
文章编号: N21111705
期刊: Proceedings of the National Academy of Sciences
作者: Min Song, Florence Schubotz, Matthias Y. Kellermann, Christian T. Hansen, Wolfgang Bach, Andreas P. Teske, Kai-Uwe Hinrichs
更新时间: 2021-11-17
摘要: A mechanistic understanding of formation pathways of low-molecular-weight hydrocarbons is relevant for disciplines such as atmospheric chemistry, geology, and astrobiology. The patterns of stable carbon isotopic compositions (δ 13 C) of hydrocarbons are commonly used to distinguish biological, thermogenic, and abiotic sources. Here, we report unusual isotope patterns of nonmethane hydrocarbons in hydrothermally heated sediments of the Guaymas Basin; these nonmethane hydrocarbons are notably 13 C-enriched relative to sedimentary organic matter and display an isotope pattern that is reversed relative to thermogenic hydrocarbons (i.e., δ 13 C ethane > δ 13 C propane > δ 13 C n -butane > δ 13 C n -pentane). We hypothesized that this pattern results from abiotic reductive conversion of volatile fatty acids, which were isotopically enriched due to prior equilibration of their carboxyl carbon with dissolved inorganic carbon. This hypothesis was tested by hydrous pyrolysis experiments with isotopically labeled substrates at 350 °C and 400 bar that demonstrated 1) the exchange of carboxyl carbon of C 2 to C 5 volatile fatty acids with 13 C-bicarbonate and 2) the incorporation of 13 C from 13 C-2–acetic acid into ethane and propane. Collectively, our results reveal an abiotic formation pathway for nonmethane hydrocarbons, which may be sufficiently active in organic-rich, geothermally heated sediments and petroleum systems to affect isotopic compositions of nonmethane hydrocarbons.

17726. 题目: Stepwise freezing-thawing treatment promotes short-chain fatty acids production from waste activated sludge
文章编号: N21111704
期刊: Science of The Total Environment
作者: Cong-Cong Tang, Xing-Ye Yao, Hong-Yu Jin, Qian Sun, Zheng-Shuo Zou, Wen-Jing Yang, Zhang-Wei He, Ai-Juan Zhou, Fan Chen, Yong-Xiang Ren, Wen-Zong Liu, Aijie Wang
更新时间: 2021-11-17
摘要: Waste activated sludge (WAS), as the byproducts of wastewater treatment plants, has been greatly produced. With high cost and environmental risk of WAS disposal, to explore a low-cost and environment-friendly technology has been a great challenge. Considering that WAS is a collection of organic matters, anaerobic fermentation has been selected as a sustainable way to simultaneously recover resources and reduce environmental pollution. To recover short-chain fatty acids (SCFAs) has gained great concern because of the high value-added application and high-efficiency production process. Considering the temperature in some areas of the world can reach to below 0 °C, this study proposed an efficient strategy, i.e., stepwise freezing and thawing treatment, to promote SCFAs production. The maximal production of SCFAs, i.e., 246 mg COD/g volatile suspended solid, was obtained with the shortened retention time of five days. Mechanistic studies showed that the solubilization of both extracellular polymeric substances (EPSs) and microbial cells could be accelerated, with the EPSs removal of 58.3% for proteins and 59.0% for polysaccharides. Also, the hydrolysis process was promoted to provide more substrates for subsequent acidogenisis, and the functional microorganisms, such as Romboutsia, Paraclostridium, Macellibacteroides and Conexibacter, were greatly enriched, with a total abundance of 26.2%. Moreover, compared to control, methanogenesis was inhibited at a shortened sludge retention time (e.g., five days), which benefited to the accumulation of SCFAs, but the methane production was increased by 25.2% at a longer sludge retention time (e.g., ten days). Thus, these findings of this work may provide some new solutions for the enhanced resource recovery from WAS, and further for carbon-neutral operation of wastewater treatment plants.

17727. 题目: Biochar applications enhance the phytoextraction potential of Salix smithiana [Willd.] (willow) in heavily contaminated soil: potential for a sustainable remediation method?
文章编号: N21111703
期刊: Journal of Soils and Sediments
作者: Kateřina Pračke, Jiřina Száková, Pavel Tlustoš
更新时间: 2021-11-17
摘要: Purpose The combination of chemostabilization and phytoextraction provide an affordable and environmentally effective remediation technology for the heavy metals in contaminated soils. The purpose of this study was to investigate how biochar applications in heavily contaminated alluvium soils reduced the toxic effects of heavy metal (Cd, Pb, Zn) and their transport through the soil profile. Materials and methods The 3-year experiment was conducted under controlled conditions in greenhouse. Extremely contaminated soil required high doses (5, 10, and 15% w/w) of biochar. Biochar was prepared from wood by high-temperature pyrolysis (800 °C). Salix smithiana Willd. was chosen as a model plant. Leachate describing the mobility of metals was collected five times during each vegetative period. Leachate was collected. Results and discussion Biochar application enhanced the phytoextraction potential of willow plants in the first and second year of a pot experiment. High biochar applications (5, 10, and 15% w/w) reduced the phytotoxicity of metals in soil solution, improved biomass growth in Salix smithiana, and enhanced heavy metal uptake by plants in the amendment treatments. In the 3rd year, the pH of both the soil and leachate decreased by 1 unit. The decrease of pH led to the increase of Cd and Zn in the leachate and/or limited the growth of plants. Conclusions Biochar seems to be an effective tool for heavy metal immobilization; however, further research is necessary to evaluate the mechanisms of biochar behavior and subsequent utilization for remediation of extremely contaminated alluvial soils.

17728. 题目: Tracer elements revealed the soil organic carbon sources in a dam-controlled watershed
文章编号: N21111702
期刊: Soil and Tillage Research
作者: Yi Zhang, Peng Li, Xiao-jun Liu, Lie Xiao, Zhi-neng Li, Heng Wu, Shi-xuan Zhou, Ming-xing Ren
更新时间: 2021-11-17
摘要: The dynamics of the soil organic carbon (SOC) pool and the mechanisms that underpin those dynamics are at the frontier of terrestrial carbon (C) cycling research. Soil erosion seriously affects the migration and redistribution of SOC, driving a critical part of the C cycle. In this study, soil samples were collected from a 14.69 m sediment profile formed between 1960 and 2017, which was located in a small agricultural catchment on the Loess Plateau in northwest China. Nuclear tracer elements (137Cs, 210Pb) and stable C isotopes (δ13C) from organic matter were used to quantitatively identify the SOC sources in different siltation stages. The method used assumes that the contribution of a source is proportional to the elemental concentration in that source. SOC in soil samples from different erosion source areas (farmland, forest land, grassland, shrub land and ditch wall) were compared against the deposit in the check dam. The concentration of SOC in the sediments of the check dam was between 1.21 g kg−1 and 4.03 g kg−1. Nearly half of the SOC in the check dam sediments was traced back to the ditch wall. Farmland contributed 24.8 %, while shrub land contributed the least SOC at 0.4 %. SOC erosion attributed to farmland decreased gradually, while the relative contribution from the ditch wall increased. Within the agricultural catchment area, there was a net migration of SOC from the various land cover types (the source) to the sedimentary area behind the dam (the sink). These results indicate that a dynamic balance exists between redistribution and heterotopic storage of SOC during sedimentation. This study provides an opinion for sediment source identification and the soil C cycle in watersheds on the Loess Plateau.

17729. 题目: A state-of-the-art review on algae pyrolysis for bioenergy and biochar production
文章编号: N21111701
期刊: Bioresource Technology
作者: Jiacheng Sun, Omid Norouzi, Ondřej Mašek
更新时间: 2021-11-17
摘要: Algae, as a feedstock with minimum land footprint, is considered a promising biomass for sustainable fuels, chemicals, and materials. Unlike lignocellulosic biomass, algae consist mainly of lipids, carbohydrates, and proteins. This review focusses on the bio-oil and biochar co-products of algae-pyrolysis and presents the current state-of-the-art in the pyrolysis technologies and key applications of algal biochar. Algal biochar holds potential to be a cost-effective fertilizer, as it has high P, N and other nutrient contents. Beyond soil applications, algae-derived biochar has many other applications, such as wastewater-treatment, due to its porous structure and strong ion-exchange capacity. High specific capacitance and stability also make algal biochar a potential supercapacitor material. Furthermore, algal biochar can be great catalysts (or catalyst supports). This review sheds light on a wide range of algae-pyrolysis related topics, including advanced-pyrolysis techniques and the potential biochar applications in soil amendment, energy storage, catalysts, chemical industries, and wastewater-treatment plants.

17730. 题目: Andic Soil Properties and Tephra Layers Hamper C Turnover in Icelandic Peatlands
文章编号: N21111613
期刊: Journal of Geophysical Research: Biogeosciences
作者: Susanne Claudia Möckel, Egill Erlendsson, Guðrún Gísladóttir
更新时间: 2021-11-16
摘要: Due to frequent volcanic activity and erosion of dryland soils, magnified by land use after human settlement (c. 870 AD), peatlands in Iceland receive regular additions of mineral aeolian deposits. Their soils may develop not only histic, but also andic characteristics. Yet, mineral aeolian deposition as an environmental determinant of peatlands in Iceland is still poorly understood, not least with regard to the peatlands carbon (C) stores. This study advances our understanding of the impact of tephra deposition on Histosols by elucidating interactions between C characteristics and andic soil properties. We compare Histosols from three Icelandic peatlands of different degree of exposure to aeolian deposition by evaluating datasets of their C structure derived by 13C NMR spectroscopy, andic soil properties based on selective extractions of Al, Fe and Si, and decomposition proxies C/N, δ13C and δ15N. By applying multivariate statistical methods, we are able to present several important patterns. Soil organic matter of Histosols with andic properties is less decomposed than that of Histosols without notable andic properties. Andic soil properties seem to impact their C structure by facilitating the formation of organo-mineral complexes, which particularly hamper the decomposition of chemically more labile C groups. Tephra layers appear to hamper microbial activity in deeper soil layers by preventing input of fresh organic matter. The interaction of andic and histic soil properties and the protective role of major tephra deposits, may enable an unusual potential for long-term C stabilization in a natural peatland environment.

17731. 题目: Effects of ant colonies on molecular characteristics of dissolved organic matter in peatland soils, Northeast China
文章编号: N21111612
期刊: Applied Soil Ecology
作者: Xuehui Zhang, Yuan Xin, Zhongsheng Zhang, Zimo Zhang,
更新时间: 2021-11-16
摘要: Increasing water discharge has resulted in rising dissolved organic matter (DOM) in draining peatlands. However, how contents and spectral characteristics of DOM changed by increasing terrestrial ants in peatland with water level decreasing, were not well revealed. In the present work, chemical and molecular composition of DOM in ant and nearby soils were characterized using UV–Visible absorption and fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC). Results indicated that four fluorescence components were identified, of which endogenetic fluorophores accounted for a higher proportion (79.21 ± 0.06%) of the total variability of all four. DOM from ant mound soils had lower aromaticity, humification degree, and smaller molecular size than those from control soil. The influence of microorganisms on the content and structure of DOM was crucial in the ant mound soil, whereas the effect from soil physicochemical properties was apparently more pronounced in the control soil. The study demonstrated that the endogenetic and microbial substances were closely related to the compositional variability of DOM in ant and control soils of peatlands.

17732. 题目: Reassessing riverine carbon dioxide emissions from the Indian subcontinent
文章编号: N21111611
期刊: Science of The Total Environment
作者: Omme K. Nayna, Vedula V.S.S. Sarma, Most Shirina Begum, Jens Hartmann, Sanjeev Kumar, Shafi M. Tareq, Ji-Hyung Park
更新时间: 2021-11-16
摘要: Anthropogenic perturbations are increasing uncertainties in estimating CO2 emissions via air-water CO2 flux (FCO2) from large rivers of the Indian subcontinent. This study aimed to provide an improved estimate of the total FCO2 from the subcontinental rivers by combining calculations of the partial pressure of CO2 (pCO2) in eight major rivers with new measurements in the Ganges and Godavari. The average pCO2 in the two newly surveyed rivers, including tributaries, wastewater drains, and impoundments, were 3–6 times greater than the previously reported values. In some highly polluted urban tributaries and middle reaches of the Ganges that drain metropolitan areas, the measured pCO2 exceeded 20,000 μatm, ~40 times the background levels of the headwaters originating in the carbonate-rich Himalayas. The high pCO2 above 28,000 μatm in the lower reach of the Godavari was seven times the moderate levels of pCO2 in the headwaters of the volcanic Deccan Traps, indicating enhanced CO2 production in soils and anthropogenic sources under favorable conditions for organic matter degradation. Across the northern rivers, pCO2 exhibited a significant negative relationship with dissolved oxygen, but a positive relationship with inorganic N or P concentrations. The strong influence of water pollution on riverine pCO2 suggests that CO2 emissions from hypoxic, eutrophic reaches can greatly exceed phytoplanktonic CO2 uptake. Spatially resolved pCO2 data, combined with three gas transfer velocity estimates, provided a higher range of FCO2 from the subcontinental rivers (100.9–130.2 Tg CO2·yr−1) than the previous estimates (7.5–61.2 Tg CO2·yr−1). The revised estimates representing 2–5% of the global riverine FCO2 illustrate the importance of the Indian subcontinental rivers under increasing anthropogenic pressures in constraining global inland waters FCO2.

17733. 题目: Inhibition by phenolic antioxidants of the degradation of aromatic amines and sulfadiazine by the carbonate radical (CO3•−)
文章编号: N21111610
期刊: Water Research
作者: Luca Carena, Davide Vione, Marco Minella, Silvio Canonica, Ursula Schönenberger
更新时间: 2021-11-16
摘要: The carbonate radical CO3•− and the excited triplet states of chromophoric dissolved organic matter play an important role in the photodegradation of some easily oxidized pollutants in surface waters, such as the aromatic amines. Anilines and sulfadiazine are known to undergo back-reduction processes when their degradation is mediated by the excited triplet states of photosensitizers (triplet sensitization). Back-reduction, which inhibits photodegradation, means that phenols or the antioxidant (mostly phenolic) moieties occurring in the natural dissolved organic matter of surface waters reduce, back to the parent compounds, the radical species derived from the mono-electronic oxidation of anilines and sulfadiazine. Here we show that a similar process takes place as well in the case of substrate oxidation by CO3•−. The carbonate radical was here produced upon oxidation of HCO3−/CO32− by either HO•, generated by nitrate photolysis, or SO4•−, obtained by photolysis of persulfate. Back-reduction was observed in both cases in the presence of phenols, but at different extents as far as the details of reaction kinetics are concerned, and the occurrence of additional reductants might affect the efficacy by which phenols carry out the reduction process. In particular, when the carbonate radicals were produced by NO3– photolysis in the presence of HCO3−/CO32−, the numerical values of [PhOH]1/2 (the phenol concentration that halves the photodegradation rate of the substrate) were 2.19 ± 0.23 µM for aniline, 1.15 ± 0.25 µM for 3-chloroaniline, 1.18 ± 0.26 µM for 4-chloroaniline, and 1.18 ± 0.22 µM for 3,4-dichloroaniline. In contrast, when CO3•− was produced by photolysis of persulfate in the presence of HCO3−/CO32−, the corresponding values were 0.28 ± 0.02 μM for aniline and 0.79 ± 0.10 μM for sulfadiazine. Back-reduction has the potential to significantly inhibit photodegradation by CO3•− and excited triplet states in natural waters, and to comparatively increase the importance of HO•-mediated degradation that is not affected by the same phenomenon.

17734. 题目: Reducing environmental risks of chlorpyrifos application in typical soils by adding appropriate exogenous organic matter: Evidence from a simulated paddy field experiment
文章编号: N21111609
期刊: Environmental Pollution
作者: Dahang Shen, Kaixiang Yu, Jirong Hu, Jiayin Zhong, Guoqing Shen, Qingfu Ye, Wei Wang
更新时间: 2021-11-16
摘要: Chlorpyrifos (CPF), as an organophosphate insecticide extensively used in the modern agricultural system, has been gradually banned in many countries due to its reported health risks to organisms, including humans. This study used simulated paddy field experiments and carbon-14 tracing to explore the possibility of reducing environmental risks of chlorpyrifos application through appropriate agronomic practice. Results showed 14C-CPF concentration in rice plants planted in the red soil (RS) was significantly higher than that in black soil (BS) and fluvo-aquic soil (FS). The application of biochar and chicken manure in RS reduced 14C-CPF accumulation in rice plants, and the content of 14C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of 14C-CPF, especially in FS with the highest risk of 14C-CPF migration. The addition of chicken manure in FS reduced the migration of 14C-CPF and the total residual amount of 14C-CPF in the soil. In addition, chicken manure treatment increased the formation of 14C-bound residues (BRs) in soils and changed the distribution 14C-BRs in humus. The results indicated that the degree of environmental risks associated with the CPF application varies with soil types and could be reduced by introducing suitable exogenous organic matter into different soils, which is of great significance for guiding the scientific application of chlorpyrifos in agronomic practices.

17735. 题目: The impact of silver nanoparticles on microbial communities and antibiotic resistance determinants in the environment
文章编号: N21111608
期刊: Environmental Pollution
作者: Kevin Yonathan, Riti Mann, Khandaker Rayhan Mahbub, Cindy Gunawan
更新时间: 2021-11-16
摘要: Nanosilver (NAg) is currently one of the major alternative antimicrobials to control microorganisms. With its broad-spectrum efficacy and lucrative commercial values, NAg has been used in medical devices and increasingly, in consumer products and appliances. This widespread use has inevitably led to the release and accumulation of the nanoparticle in water and sediment, in soil and even, wastewater treatment plants (WWTPs). This Article describes the physical and chemical transformations of NAg as well as the impact of the nanoparticle on microbial communities in different environmental settings; how the nanoparticle shifts not only the diversity and abundance of microbes, including those that are important in nitrogen cycles and decomposition of organic matters, but also their associated genes and in turn, the key metabolic processes. Current findings on the microbiological activity of the leached soluble silver, solid silver particulates and their respective transformed products, which underpin the mechanism of the nanoparticle toxicity in environmental microbes, is critically discussed. The Article also addresses the emerging evidence of silver-driven co-selection of antibiotic resistance determinants. The mechanism has been linked to the increasing pools of many antibiotic resistance genes already detected in samples from different environmental settings, which could ultimately find their ways to animals and human. The realized ecological impact of NAg calls for more judicial use of the nanoparticle. The generated knowledge can inform strategies for a better ‘risks versus benefits’ assessment of NAg applications, including the disposal stage.

17736. 题目: Biochar suppresses bacterial wilt disease of flue-cured tobacco by improving soil health and functional diversity of rhizosphere microorganisms
文章编号: N21111607
期刊: Applied Soil Ecology
作者: Chengjiang Li, Waqar Ahmed, Dafei Li, Liangjun Yu, Long Xu, Tianyang Xu, Zhengxiong Zhao
更新时间: 2021-11-16
摘要: Bacterial wilt caused by Ralstonia solanacearum is a devastating disease of flue-cured tobacco production. Amendments of biochar in soil suppress the incidence of bacterial wilt disease by improving soil health and functional diversity of rhizosphere microbes. In this study, we observed the effect of 0–5% application rate of tobacco stem biochar on soil health and the occurrence of tobacco bacterial wilt disease. Results demonstrated that the application of 2% tobacco stem biochar significantly improves soil physicochemical properties, microbial biomass carbon and nitrogen, and the functional diversity of microbes in the rhizosphere. The ability of rhizosphere microorganisms to utilize six types of carbon sources was significantly improved under the 2% application rate of tobacco stem biochar, which reduced the incidence of bacterial wilt disease and R. solanacearum population in the rhizosphere of tobacco plants. Biochar also increases the accumulation of dry matter contents in the roots, stems, and leaves of tobacco plant. We conclude that tobacco stem biochar at a certain level improves the soil physicochemical properties, functional diversity of rhizosphere microorganisms, mitigates the pathogen population, and reduces disease incidence. This study highlights the potential use of tobacco stem biochar to manage the bacterial wilt disease.

17737. 题目: Comparative study on the potential risk of contaminated-rice straw, its derived biochar and phosphorus modified biochar as an amendment and their implication for environment
文章编号: N21111606
期刊: Environmental Pollution
作者: Yutong Zong, Han Chen, Zaffar Malik, Qing Xiao, Shenggao Lu
更新时间: 2021-11-16
摘要: Direct application of contaminated-rice straw (CRS) to soil can cause the secondary pollution in agricultural land because of high content of Cd in rice straw. This study employed biochar or modified biochar technique to reduce the potential pollution risk of Cd in CRS. In the pot experiment, the CRS, straw biochar prepared at 300 °C (B300) and 500 °C (B500), and phosphorus modified biochar pyrolyzed at 300 °C (PB300) and 500 °C (PB500) were added at dosage of 5% into three typical paddy soils. The results showed that CRS and its derived biochar could enhance soil pH, EC, Eh, organic carbon, exchangeable base cations (K+, Na+, Ca2+ and Mg2+), and available phosphate. The application of CRS, biochar and phosphorus modified biochar significantly increased the contents of total Cd in soils relative to control soil. Compared to CRS, the biochar application (especially the PB500) decreased the contents of 0.01M CaCl2-extractable Cd. The application of CRS significantly increased the content of exchangeable Cd fraction (F1), whereas biochar increased residual Cd content (F4). The biochar and phosphorous modified biochar significantly decreased the contents of bioavailable Cd in soils compared to CRS application. The increased soil pH and dissolve organic matter were found to be the main factors in reducing the release of Cd in biochar. The possible mechanisms of biochar in reducing bioavailability of Cd were to significantly increase soil pH, enhance the complexation of Cd ions, and promote the transformation of Cd from easily available to stable (residual) forms. It could conclude that conversion of contaminated rice straw into biochar was an efficient way to minimize Cd availability in soil and reduce the pollution risk of Cd in rice straw.

17738. 题目: Effects of demineralization on food waste biochar for co-firing: Behaviors of alkali and alkaline earth metals and chlorine
文章编号: N21111605
期刊: Waste Management
作者: Ye-Eun Lee, Yoonah Jeong, Dong-Chul Shin, Yeong-Seok Yoo, Kwang-Ho Ahn, Jinhong Jung, I-Tae Kim
更新时间: 2021-11-16
摘要: A significant amount of chlorine, and alkali and alkaline earth metal (AAEM) in food waste has been a major limitation to the utilization of food waste as fuel. The present study aims to investigate the behavior of chlorine and AAEM in food waste biochar during pyrolysis, demineralization, and combustion. Food waste compost (FWC) and food waste feedstock (FWF) were selected as raw materials. Three different pyrolysis temperatures from 300 to 500 °C and two demineralization processes, water and CO2–saturated water, were employed. As the pyrolysis temperature increased, crystallized salt was removed through demineralization, which further increased the heating value. Effective removal of chlorine was demonstrated in both demineralization methods. During demineralization, re-adsorption of Ca on food waste biochar occurred, which was alleviated by CO2-water demineralization. The total amounts of volatilized Cl and AAEM after CO2–water demineralization were reduced by 74.79–99.38% for FWF and 98.34–99.9% for FWC compared to raw biochar. Furthermore, slagging and fouling potentials for all food waste biochar samples were estimated using various indices. The proposed behavior of Cl and AAEM in food waste biochar during various fabrication conditions provides insight into how food waste biochar can be applied in thermos-electric power plant for co-firing with coal.

17739. 题目: Fungi drive soil multifunctionality in the coastal salt marsh ecosystem
文章编号: N21111604
期刊: Science of The Total Environment
作者: Jing Li, Lijuan Cui, Manuel Delgado-Baquerizo, Juntao Wang, Yinuo Zhu, Rumiao Wang, Wei Li, Yinru Lei, Xiajie Zhai, Xinsheng Zhao, Brajesh K. Singh
更新时间: 2021-11-16
摘要: Salt marshes are highly productive intertidal wetlands located in temperate climatic zones, in which marine-to-terrestrial transition significantly influences microbial life. Numerous studies revealed the important coupling relationship between microbial diversity and ecosystem functions in terrestrial ecosystem, however, the importance of microbial diversity in maintaining soil function in coastal ecosystems remains poorly understood. Here, we studied the shifts of microbial communities and soil multifunctionality (SMF; nine functions related with C, N and P cycling) along a vegetation gradient in a salt marsh ecosystem and investigated the microbial diversity-function relationship. The aboveground vegetation shifted from mud flat (MF) to Scirpus triqueter (SM) and then Phragmites australis (PA) with increasing distance away from the sea. Average approach showed that the SMF was much higher in halophytes covered zones including SM and PA than in mud flat, and structural equation model (SEM) analysis confirmed that vegetation was an important predictor on SMF besides moisture and organic carbon. Linear regression and multiple threshold methods showed that in MF zone and SM zone, fungal rather than bacterial richness was significantly and positively correlated with SMF, while in the PA zone microbial diversity did not relate with SMF. Random forest analysis identified several Ascomycota taxa with preference over marine environment as strong predictors of SMF. Taken together, our study lays the basis for a better understanding of the relationships between belowground microbial diversity and soil functions in salt marshes.

17740. 题目: Hydroxyl radicals induced mineralization of organic carbon during oxygenation of ferrous mineral-organic matter associations: Adsorption versus coprecipitation
文章编号: N21111603
期刊: Science of The Total Environment
作者: Mengxi Tan, Shaochong Liu, Ning Chen, Yuliang Li, Liqiang Ge, Changyin Zhu, Dongmei Zhou
更新时间: 2021-11-16
摘要: The iron (Fe) phases have been widely proposed to preserve organic carbon (OC) via adsorption or coprecipitation pathways, however, such role of Fe phases might be largely reversed under redox-fluctuation conditions, especially for Fe(II) minerals-protected OC. In this study, we synthesized the Fe(II)-OC associations via adsorption and coprecipitation using FeCO3 and three types of low-molecular-weight organic compounds (LMWOCs) at different C/Fe molar ratios, and investigated the OC mineralization induced by hydroxyl radicals (OH) during oxygenation processes. Abundant OH can be produced upon oxygenation of FeCO3-LMWOCs associations within 96 h, giving values of 28.49–151.36 μM in adsorption and 12.63–76.41 μM in coprecipitation treatments depended on types of LMWOCs and C/Fe molar ratios. Fe(II) species in coprecipitates with hydroquinone (HQ) mainly transformed into Goethite-like phases after oxygenation, while adsorption samples induced more formation of lower-crystalline Fe phase (e.g., ferrihydrite). The surface-Fe(II) was the primary electron donors to O2, which further induced hydrogen peroxide (H2O2) formation via one- and two-electron transfer pathways. Finally, the produced OH removed 0.55–9.65 and 0.16–85.54 mg L−1 total OC in adsorption and coprecipitation treatments after oxygenation. Collectively, this study highlights that OC associated with Fe(II) minerals might be labile due to the oxidation of formed OH, and the role of Fe phases in OC sequestration may be further re-evaluated under redox fluctuation conditions.