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17501. 题目: Enhanced extracellular polymeric substances production and aggravated membrane fouling potential caused by different disinfection treatment
文章编号: N21102813
期刊: Journal of Membrane Science
作者: Gen-Qiang Chen, Yin-Hu Wu, Zhuo Chen, Li-Wei Luo, Yun-Hong Wang, Xing Tong, Yuan Bai, Hao-Bin Wang, Yu-Qing Xu, Zi-Wei Zhang, Nozomu Ikuno, Hong-Ying Hu
更新时间: 2021-10-28
摘要: Extracellular polymeric substances (EPS) were the main cause of membrane biofouling in advanced treatment of wastewater. Disinfection was usually used to reduce microbial concentration in the feed water and prevent biofouling. However, the disinfection residual bacteria (DRB) could regrow to produce EPS, and there was still a paucity of information on EPS productivity and properties from DRB and their further interaction with membranes. In this study, three commonly-used disinfection methods (free chlorine, chloramine and ozone disinfection) were used to investigate their effects on microbial EPS production and the further effects on membrane fouling. It was found all the disinfection treatment increased the relative abundance of typical bacterial genus with high EPS production ability, and thus significantly enhanced EPS volumetric productivity (by 26%–82%). The molecular weight and fluorescence intensity of EPS produced by DRB also increased. The fouling potential of these EPS on ultrafiltration (UF) membranes and reverse osmosis (RO) membranes was then tested. EPS of DRB showed significantly higher fouling potential. Compared with the control group, the time for transmembrane pressure (TMP) increased to 3 bar decreased by 43%–49% in the constant-flow UF system in the disinfection groups. As for the constant-pressure RO systems, the final flux decreased by 33%–41% in the disinfection groups compared with the control group. The thickness of foulants on UF and RO membranes in the disinfection groups was all higher than that in the control group. The extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory further showed that the EPS of DRB had significantly higher interaction energy with membranes than that in the control group. Therefore, caution should be exercised when oxidizing disinfection was used as pre-treatment for membrane filtration in the wastewater reclamation process.

17502. 题目: Can aged biochar offset soil greenhouse gas emissions from crop residue amendments in saline and non-saline soils under laboratory conditions?
文章编号: N21102812
期刊: Science of The Total Environment
作者: Ningguo Zheng, Yongxiang Yu, Yaying Li, Chaorong Ge, Stephen J. Chapman, Huaiying Yao
更新时间: 2021-10-28
摘要: Applying biochar in association with crop residues might optimize costs and effectiveness in the reclamation of saline soils. Here, we explored the potential effects of biochar in association with crop residue amendments on soil greenhouse gas (GHG) emissions, and microbial communities. Previously, we found that soil N2O emission significantly increased with increasing salinity levels followed by cotton straw addition. In the present study, microcosm experiments were performed to investigate the interaction of salinity (0 and 1.2% salt) with the aging of biochar following soil amendments over an incubation period of 80 days. The results indicated that N2O emissions were approximately 5–10 times higher in saline soils than in non-saline soils, and the cumulative N2O emissions following two straw amendments treatment were the highest of all the treatments. Salinity increased the contribution of nitrification to soil N2O emissions stimulated by the cotton straw amendments, and aged biochar performed better in decreasing soil N2O emissions in saline soils than in non-saline soils. In addition, aged biochar increased soil C mineralization and CO2 emissions under saline conditions. Soil CO2 and N2O emissions were affected by both soil abiotic and biotic factors under non-saline and saline conditions. Moreover, much more specific but fewer microbial groups survived and utilized crop residues under saline than non-saline conditions, and aged biochar decreased salt stress in soil microorganisms. These findings indicated that aged biochar and crop residues together would be an optimal way to address soil C storage and mitigate N2O emissions under saline conditions.

17503. 题目: Tephra deposition and bonding with reactive oxides enhances burial of organic carbon in the Bering Sea
文章编号: N21102811
期刊: Global Biogeochemical Cycles
作者: Jack Longman, Thomas M. Gernon, Martin R. Palmer, Hayley R. Manners
更新时间: 2021-10-28
摘要: Preservation of organic carbon (OC) in marine sediments exerts a major control on the cycling of carbon in the Earth system. In these marine environments, OC preservation may be enhanced by diagenetic reactions in locations where deposition of fragmental volcanic material called tephra occurs. While the mechanisms by which this process occurs are well understood, site-specific studies of this process are limited. Here, we report a study of sediments from the Bering Sea (IODP Site U1339D) to investigate the effects of marine tephra deposition on carbon cycling during the Pleistocene and Holocene. Our results suggest that tephra layers are loci of OC burial with distinct δ13C values, and that this process is primarily linked to bonding of OC with reactive metals, accounting for ∼80% of all OC within tephra layers. In addition, distribution of reactive metals from the tephra into non-volcanic sediments above and below the tephra layers enhances OC preservation in these sediments, with ∼33% of OC bound to reactive phases. Importantly, OC-Fe coupling is evident in sediments >700,000 years old. Thus, these interactions may help explain the observed preservation of OC in ancient marine sediments.

17504. 题目: Carbon, nutrient and metal controls on phytoplankton concentration and biodiversity in thermokarst lakes of latitudinal gradient from isolated to continuous permafrost
文章编号: N21102810
期刊: Science of The Total Environment
作者: Oleg S. Pokrovsky, Rinat M. Manasypov, Oksana A. Pavlova, Liudmila S. Shirokova, Sergey N. Vorobyev
更新时间: 2021-10-28
摘要: Shallow thaw (thermokarst) lakes abundant in regions of permafrost-affected peatlands represent important sources of carbon dioxide and methane emission to the atmosphere, however the quantitative parameters of phytoplankton communities which control the C cycle in these lakes remain poorly known. This is especially true considering the roles of permafrost, hydrochemical composition of lakes, lake sizes and season as major governing factors on phytoplankton abundance and biodiversity. In this work, we quantified phytoplankton characteristics of 27 thermokarst lakes (sizes ranging from 115 m2 to 1.24 km2) sampled in spring, summer and autumn across a permafrost gradient (isolated, sporadic, discontinuous and continuous zone) in the Western Siberia Lowland (WSL). The biodiversity indices were highest during all seasons in lakes of the continuous permafrost zone and rather similar in lakes of isolated, sporadic and discontinuous permafrost zone. Considering all seasons and permafrost zones, the biomass and cell number of phytoplankton correlated with Dissolved Organic Carbon (DOC), phosphate, and some metal micro-nutrients (Ni, Zn). The strongest correlations were observed for Cyanophycea during summer, with pH, Ni, Cu, Zn, Sr, Ba (cell number) and Cu, Zn, Ba (biomass), and during autumn, with DOC, K, Cr, Cu, Zn, Ba, Cd, Pb (biomass). Using a substituting space for time approach for climate warming and permafrost thaw and suggesting a shift in permafrost boundaries northward, we foresee an increase in cell number and biomass in continuous permafrost zone in spring and summer, and a decrease in phytoplankton abundance in the discontinuous and sporadic permafrost zones. The biodiversity of phytoplankton in the continuous permafrost zone might decrease whereas in other zones, it may not exhibit any sizably change. However, in case of strong deepening of the active layer down to underlaying mineral horizons, and the release of some limiting nutrients (Si, P) due to enhanced connectivity of the lake with groundwater, the share of cyanobacteria and diatoms may increase.

17505. 题目: Kill three birds with one stone: Iron-doped graphitic biochar from biogas residues for ammonium persulfate activation to simultaneously degrade benzo[a]pyrene and improve lettuce growth
文章编号: N21102809
期刊: Chemical Engineering Journal
作者: Xiaoying Li, Zhou Yu, Qincheng Chen, Chen Wang, Li Ma, Guoqing Shen
更新时间: 2021-10-28
摘要: A graphitized magnetic biochar material, Fe-impregnated biochar (FBC), was synthesized using biogas residue, a product of food waste after anaerobic fermentation. The FBC coupled with ammonium persulfate (APS) exhibited excellent performance in the catalytic degradation of benzo[a]pyrene (BaP), a pentacyclic polycyclic aromatic hydrocarbon (PAH). In the FBC-APS system, the pyrolysis temperature of biochar, the initial pH, and the FBC and APS dosages were all influencing factors for Bap degradation. The FBC at the pyrolysis temperature of 700°C performed the best catalytic performance, and FBC-APS efficiently degraded BaP at a wide pH range of 3–11. Results from quenching experiments, electron spin resonance measurement, and electrochemical analysis were used as the basis to propose the possible degradation mechanisms of BaP by FBC-APS, including the radical and non-radical pathways. The radical-induced oxidation was attained by SO4·− and O2·−. The non-radical pathway involved two aspects, one contributed by 1O2 and the other achieved through electron transfer. Six BaP intermediates were tentatively determined. Finally, FBC-APS was applied to BaP-polluted soil, and the overall degradation rate reached 91.7% after 72 h. Lettuce growth experiment showed that FBC-APS enhanced soil nitrogen and potassium availability and lettuce growth. In summary, FBC-APS application to soil can degrade BaP, improve the manurial effect, and solve environmental problems brought by biogas residues, that is, killing three birds with one stone.

17506. 题目: Effects of pine sawdust and shrimp shell biochar on anaerobic digestion under different acidification conditions
文章编号: N21102808
期刊: Journal of Environmental Chemical Engineering
作者: Tian Wenjing, Jiang Qin, Junyan Liu, Feng Liu, Li Gu
更新时间: 2021-10-28
摘要: Effects of different types of biochar (pine sawdust biochar (PSBC) and shrimp shell biochar (SSBC) on anaerobic digestion under different acidification conditions were studied and compared. Compared with PSBC, SSBC had more alkaline functional groups and higher conductivity. As a result, PSBC and SSBC posed different impacts on the anaerobic digestion system under different acid inhibition conditions. In the case of less acidification, PSBC and SSBC reduced the lag time in methane production from 10.2 d to 6.3 d and 3.5 d, but didn’t present significantly improvement in the final CH4 production. But regarding more serious acid stress, PSBC-added and SSBC-added digesters respectively obtained the specific methane yield of 266.8 and 280.0 mL CH4/g VSS, 7.6 % and 12.9% higher than the control digester. Both PSBC and SSBC showed pH buffering potency and the ability to promote the degradation of volatile fatty acids, while the latter was superior to the former. On the one hand, this might be due to more basic functional groups and more areas for microbial attachment existing on the surface of SSBC, which was expected to buffer the acid shock and promote microbial growth; on the other hand, according to microbial diversity analysis, the SSBC was likely to stimulate direct interspecific electron transfer, thereby accelerating methane production.

17507. 题目: A perfect storm: An anomalous offshore phytoplankton bloom event in the NE Atlantic (March 2009)
文章编号: N21102807
期刊: Science of The Total Environment
作者: Afonso Ferreira, Joaquim Dias, Vanda Brotas, Ana C. Brito
更新时间: 2021-10-28
摘要: While primary productivity is more stable in oceanic regions, it may vary to a great extent with the proximity to coasts, where mesoscale processes may intertwine and shape phytoplankton community composition and biomass. Sometimes, this may lead to the development of anomalous phytoplankton blooms (i.e., episodic blooms that exceed several times the average phytoplankton biomass). A massive bloom observed off the Western Iberian Coast (SW Europe) during March 2009 prompted a full investigation on its spatial and temporal extent, its causes, and its potential impact on the ecosystem. Results revealed that the March 2009 bloom was both novel in terms of biomass in a regional context and one of the largest anomalous blooms until now described in terms of relative magnitude. Its causes were due to a concurrence of long-term (deep winter MLD) and short-term factors (coastal upwelling, sudden changes in the water column, consistent offshore water transport). Its impact on the regional ecosystem is difficult to gauge, although the high concentrations of particulate organic carbon at surface during the bloom period suggests that it may have had a significant local impact. Since climate change is expected to increase the frequency and intensity of extreme weather events, it is possible that anomalous blooms will also become more frequent, expanding their role in shaping carbon export and food webs. These results are crucial for the monitoring of the Western Iberian Coast and are applicable to other complex coastal upwelling regions where phytoplankton biomass and variability have a crucial link to fisheries.

17508. 题目: Soil characteristics and microbial community structure on along elevation gradient in a Pinus armandii forest of the Qinling Mountains, China
文章编号: N21102806
期刊: Forest Ecology and Management
作者: Yonghua Zhao, Yujie Zhou, Xia Jia, Lei Han, Li Liu, Kun Ren, Xuan Ye, Zhi Qu, Yuanjie Pei
更新时间: 2021-10-28
摘要: Lots of studies have shown that elevation, plant species, and soil characteristics and their relationships significantly affect microbial community in forest soils. However, how do elevation, soil characteristics, and their relationship affect microbial community in the same plant community in different latitudes, such as warm temperature zone and subtropical zone, remains unclear. Here, microbial community structure, soil characteristics, and their relationship were analyzed in Pinus armandii forests in subtropical zone at an altitude of 1700–2300 m in the Huoditang Forest of the Qinling Mountains, China. Bacterial and fungal communities were analyzed by Illumina sequencing. Elevation showed a significant effect on soil organic matter (SOM) and pH. Proteobacteria, Acidobacteria, Ascomycota, and Basidiomycota were higher abundant phyla across elevations. Ectomycorrhizal fungi abundance decreased with increasing elevation. The fungi richness decreased with increasing elevation and was negatively and significantly correlated with SOM and elevation. The relative abundance of Acidobacteria, Verrucomicrobia, Sordariomycetes, and Eurotiomycetes and Ectomycorrhizal fungi abundance was significantly correlated with soil pH. Additionally, Agaricomycetes abundance was positively correlated (p < 0.05) with available potassium (AK) in soils. Elevation, pH, soil temperature, SOM, and AK were significant factors affecting microbial communities according to the data on Pearson and redundancy analyses. Overall, responses of soil characteristics to elevation significantly affected microbial community structure in P. armandii forests of the Qinling Mountains. The results will make us better understand the roles of microbial communities in providing ecosystem services in subtropical forests.

17509. 题目: Seasonality of dissolved organic matter in lagoon ecosystems along the Alaska Beaufort Sea coast
文章编号: N21102805
期刊: Limnology and Oceanography
作者: Craig T. Connolly, Byron C. Crump, Kenneth H. Dunton, James W. McClelland
更新时间: 2021-10-28
摘要: Seasonal variations in dissolved organic matter (DOM) fluxes from land to sea have been well documented in the Arctic, yet remarkably little is known about how DOM varies seasonally within Arctic coastal waters. This is particularly true for shallow inshore environments. Here we document seasonality of DOM in lagoons along the eastern Alaska Beaufort Sea coast during the spring ice break-up (June), summer open-water (August), and late winter ice-covered (April) periods. We measured dissolved organic carbon (DOC) concentrations, C:N ratios, and chromophoric DOM (CDOM) characteristics (SUVA254 and S275–295). On average, lagoon DOC was highest during spring (~200 μM) and lowest during winter (~120 μM). C:N and SUVA254 also differed markedly between spring (C:N ~ 28; SUVA254 ~ 3.5 L mg C−1 m−1) and winter (C:N ~ 16; SUVA254 ~ 2.2 L mg C−1 m−1). Average S275–295 values (~14–17 × 10−3 nm−1) were not significantly different among seasons, but variability in S275–295 was much lower in spring. This was attributed to terrestrial runoff based on its relatively uniform composition during the spring freshet. Seasonal variations in lagoon DOM were broadly correlated with variations in salinity (i.e., lagoon water transitioned from largely fresh in spring to hypersaline in winter), but a mixing analysis revealed strong evidence of processing and net DOC generation in summer. We also found evidence of DOC processing and build-up under the ice over the winter. This baseline understanding of DOM seasonality in Arctic lagoons is essential for evaluating climate-linked impacts on Arctic coastal ecosystems and broader feedbacks associated with carbon cycling.

17510. 题目: Spatiotemporal Distribution of Hydrophobic Organic Contaminants in Spiked‐Sediment Toxicity Tests: Measuring Total and Freely Dissolved Concentrations in Porewater and Overlying Water
文章编号: N21102804
期刊: Environmental Toxicology and Chemistry
作者: Kyoshiro Hiki, Fabian Christoph Fischer, Takahiro Nishimori, Haruna Watanabe, Hiroshi Yamamoto, Satoshi Endo
更新时间: 2021-10-28
摘要: The sediment–water interface of spiked-sediment toxicity tests is a complex exposure system, where multiple uptake pathways exist for benthic organisms. The freely dissolved concentration (Cfree) in sediment porewater has been proposed as a relevant exposure metric to hydrophobic organic contaminants (HOCs) in this system. However, Cfree has rarely been measured in spiked-sediment toxicity tests. We first developed a direct immersion solid-phase microextraction method for measuring Cfree in overlying water and porewater in a sediment test using polydimethylsiloxane-coated glass fibers, resulting in sensitive and repeatable in situ measurements of HOCs. Then, we measured Cfree and total dissolved concentrations (Cdiss) in the sediment test systems with the freshwater amphipod Hyalella azteca and thoroughly evaluated the temporal and spatial profiles of four HOCs (phenanthrene, pyrene, benzo[a]pyrene, and chlorpyrifos). Furthermore, we examined the relationship between the measured concentrations and the lethality of H. azteca. We found that the test system was far from an equilibrium state for all four chemicals tested, where Cdiss in overlying water changed over the test duration and a vertical Cfree gradient existed at the sediment–water interface. In porewater Cdiss was larger than Cfree by a factor of 170 to 220 for benzo[a]pyrene because of the strong binding to dissolved organic carbon. Comparison of the median lethal concentrations of chlorpyrifos in the sediment test and those in water-only tests indicates that Cfree in porewater was the most representative indicator for toxicity of this chemical. The method and findings presented in the present study warrant further research on the chemical transport mechanisms and the actual exposure in sediment tests using different chemicals, sediments, and test species. Environ Toxicol Chem 2021;40:3148–3158. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

17511. 题目: Unveiling the dual faces of chitosan in anaerobic digestion of waste activated sludge
文章编号: N21102803
期刊: Bioresource Technology
作者: Mengyu Yin, Hongbo Chen
更新时间: 2021-10-28
摘要: In this study, the roles of chitosan (CTS) in anaerobic digestion of Waste activated sludge (WAS) were investigated. The results show that the methane production potential of WAS is positively correlated with the CTS content. The presence of 30 g/kg total suspended solids CTS increased the cumulative methane production from 215 ± 1.52 to 272 ± 1.83 mL/g volatile suspended solids. The positively charged amino groups in CTS neutralize the hydroxyl and carboxyl groups of extracellular polymeric substances, which reduces the negative charge on the surface of sludge and promotes sludge agglomeration, thereby inhibiting the release of organic matter. CTS also inhibits hydrolysis and acidification by immobilizing hydrolases and acidulase enzymes. However, CTS flocculates humus to avoid its interference with electron transfer, thereby enhancing the activity of coenzyme F420 and methanogenesis. In addition, CTS increases the abundance of methanogens, which also contributes to methane production.

17512. 题目: Impact of Eisenia fetida earthworms and biochar on potentially toxic element mobility and health of a contaminated soil
文章编号: N21102802
期刊: Science of The Total Environment
作者: Matteo Garau, Tom Sizmur, Sean Coole, Paola Castaldi, Giovanni Garau
更新时间: 2021-10-28
摘要: This study aimed to evaluate the influence of Eisenia fetida (Savigny), added to an acidic soil contaminated with potentially toxic elements (PTEs; As, Sb, Cd, Pb, Zn) and amended with a softwood-derived biochar (2 and 5% w/w), on the mobility of PTEs and soil health (i.e. nutrient availability, enzyme activity and soil basal respiration). The PTEs bioaccumulation by E. fetida and the acute ecotoxicity effects of the amended soils were also evaluated. The interaction between earthworms and biochar led to a significant increase in soil pH, organic matter, dissolved organic carbon content, cation exchange capacity, and exchangeable Ca compared to the untreated soil. Moreover, the water-soluble and readily exchangeable PTE fraction decreased (with the exception of Sb) between 1.2- and 3.0-fold in the presence of biochar and earthworms. Earthworms, biochar, and their combination, led to a reduction of phosphomonoesterase activity which in soils amended with biochar and earthworms decreased between 2.2- and 2.5-fold with respect to the untreated soil. On the other hand, biochar and earthworms also enhanced soil basal respiration and protease activity. Although the survival rate and the weight loss of E. fetida did not change significantly with the addition of 2% biochar, adding the highest biochar percentage (5%) resulted in a survival rate that was ~2-fold lower and a weight loss that was 2.5-fold higher than the other treatments. The PTE bioaccumulation factors for E. fetida, which were less than 1 for all elements (except Cd), followed the order Cd > As>Zn > Cu > Pb > Sb and were further decreased by biochar addition. Overall, these results highlight that E. fetida and biochar, especially at 2% rate, could be used for the restoration of soil functionality in PTE-polluted environments, reducing at the same time the environmental risks posed by PTEs, at least in the short time.

17513. 题目: Interspecific differences in root exudation for three tropical seagrasses and sediment pore-water dissolved organic carbon beneath them
文章编号: N21102801
期刊: Marine Pollution Bulletin
作者: Linglan Li, Zhijian Jiang, Yunchao Wu, Jialu He, Yang Fang, Jizhen Lin, Songlin Liu, Xiaoping Huang
更新时间: 2021-10-28
摘要: Seagrass beds act as blue carbon sinks globally; however, little attention has been given to carbon dynamics in the seagrass rhizosphere. Hence, in this study, the quantity and characteristics of dissolved organic carbon (DOC) from root exudation of the three dominant tropical seagrasses (Thalassia hemprichii, Enhalus acoroides, and Cymodocea rotundata) and sediment pore water beneath them were compared, to examine their interspecific differences, and to establish a connection between seagrass root exudation and sediment carbon. The rate of root-exuded DOC from T. hemprichii (2.15 ± 1.06 mg g DW root-1 h-1) was significantly higher (p < 0.05) than that from E. acoroides (0.72 ± 0.39 mg g DW root-1 h-1) and C. rotundata (0.46 ± 0.25 mg g DW root-1 h-1). Root exudation rates were more affected by root hair density and root hair length than by root carbon, nitrogen, and soluble sugar content. Simultaneously, DOC concentrations of the sediment pore water beneath T. hemprichii, E. acoroides and C. rotundata were 22.05 ± 11.61 mg l-1, 15.55 ± 2. 66 mg l-1, and 14.32 ± 1.82 mg l-1, respectively. The corresponding absorption coefficients at 254 nm (a254) were 30.53 ± 18.00, 17.31 ± 2.24, and 14.07 ± 2.03, respectively, while the relevant specific ultraviolet absorbances at 254 nm (SUVA254) were 1.38 ± 0.29, 1.19 ± 0.26 and 1.03 ± 0.28, respectively. Therefore, the roots of T. hemprichii exuded DOC at a higher rate, leading to a higher pore-water DOC pool in the sediment. This suggests that T. hemprichii played a greater role in the sediment carbon pool through root exudation. Thus, it can be considered as the priority species for transplantation to promote the carbon sink function of seagrass beds.

17514. 题目: Adsorption of organic and inorganic arsenic from aqueous solution: Optimization, characterization and performance of Fe–Mn–Zr ternary magnetic sorbent
文章编号: N21102724
期刊: Chemosphere
作者: Shuai-Wen Zou, Kok Yuen Koh, Zhihao Chen, Yu-Yang Wang, Yu-Ming Zheng, J. Paul Chen
更新时间: 2021-10-27
摘要: Arsenic is a highly toxic pollutant and exists in inorganic and organic forms in groundwater and industrial wastewater. It is of great importance to reduce the arsenic content to lower levels in the water (e.g., <10 ppb for drinking) in order to minimize risk to humans. In this study, a Fe–Mn–Zr ternary magnetic sorbent was fabricated via precipitation for removal of inorganic and organic arsenate. The synthesis of sorbent was optimized by Taguchi method, which leads to an adsorbent with higher adsorption capacity. The adsorption of As(V) was pH dependent; the optimal removal was achieved at pH 2 and 5 for inorganic and organic As(V), respectively. Contact time of 25 h was sufficient for complete adsorption of both inorganic and organic As(V). The adsorption isotherm study revealed that the adsorbent performed better in sequestration of inorganic As(V) than that of organic As(V); both adsorption followed the Langmuir isotherm with maximum adsorption capacities of 81.3 and 16.98 mg g−1 for inorganic and organic As(V), respectively. The existence of anions in the water had more profound effect on the adsorption of organic As(V) than the inorganic As(V). The co-existing silicate and phosphate ions caused significantly negative impacts on the adsorption of both As(V). Furthermore, the existence of humic acid caused the deterioration of inorganic As(V) removal but showed insignificant impact on the organic As(V) adsorption. The mechanism study demonstrated that ion exchange and complexation played key roles in arsenic removal. This study provides a promising magnetic adsorptive material for simultaneous removal of inorganic and organic As(V).

17515. 题目: Controls on organic matter accumulation in the Bakken Formation, Williston Basin, USA
文章编号: N21102723
期刊: Chemical Geology
作者: Zain Abdi, Susan M. Rimmer, Harold D. Rowe, Stephen Nordeng
更新时间: 2021-10-27
摘要: The environmental processes and conditions controlling productivity and organic matter accumulation/preservation in the lower black shale (LBS) and upper black shale (UBS) members of the Devonian-Mississippian Bakken Formation were evaluated utilizing molybdenum (Mo), total organic carbon (TOC), total sulfur (ST), and iron (Fe) data. High-resolution (1- to 3-cm scale) chemostratigraphic records were generated for twelve drill cores, four of which closely flank the north-south-trending axis of the Nesson Anticline, proximal to the center of the Williston Basin in northwest North Dakota, USA. Degree of pyritization (DOPT) values (0.25 to 1.0) indicate that bottom waters were frequently dysoxic with intermittent aerobic and anoxic/euxinic conditions. However, the presence of organic sulfur in black shales can complicate the use of DOPT as a redox proxy requiring a multi-proxy approach to adequately elucidate depositional conditions. In such samples, the use of ST to approximate pyritic sulfur can lead to an overestimation of DOPT values. Total organic carbon contents of 2–20%, by weight, and consistently elevated Mo concentrations (>100 ppm) in both the LBS and UBS imply that the Williston Basin was often hydrographically unrestricted, allowing for ample nutrient resupply that resulted in enhanced primary productivity. Enhanced organic production (as indicated by the elevated TOC contents) was most likely supported by an abundant supply of nutrients in the basin. Using published Mo–TOC relationships from modern anoxic-euxinic basins, it is estimated that renewal time of the sub-chemoclinal water mass during accumulation of the LBS and UBS approximated 10 and 30 yr, respectively. Key differences between LBS and UBS redox proxies highlight different bottom-water redox conditions during deposition, suggesting differences in paleo-water mass geochemical characteristics and general circulation.

17516. 题目: Characteristics of humic substance in lake sediments: the case of lakes in northeastern China
文章编号: N21102722
期刊: Journal of Hydrology
作者: Xinyu Song, Chunhao Zhang, Xinya Su, Longji Zhu, Zimin Wei, Yue Zhao
更新时间: 2021-10-27
摘要: As an important part of lake ecosystems, sediments play a key role in the carbon cycle in lakes. Due to the complex sources of organic matter in sediments, the link between sequestration and transformation of humic substance is largely unknown. Therefore, it is essential to understand the characteristics of humic substance in lake sediments. In this study, the relationship between the characteristics of humic substance and environmental conditions was found in sediment samples from six typical lakes of northeast China. The structure of humic substance (HS), fulvic acid (FA) and humic acid (HA) tended to be simplified with decreasing lake depth. Pearson analysis indicated that characteristics of humic substances in deep lake sediments were dominantly determined by nutrient factors (e.g., NO3--N, NO2--N, NH4+-N) and physicochemical factors (e.g., pH, water temperature, dissolved oxygen), while the changes of HS in shallow lake sediments were dominantly determined by physicochemical factors (e.g., pH, water temperature, dissolved oxygen). Variation partitioning results also indicated that nutrient factors and physicochemical factors explained 64% and 24.2% of the variations of HS content in boreal deep lakes. In comparison, physicochemical factors explained most of the variation (35.6%) of HS composition, while nutrient factors only explained 3.4% of the variation in shallow lakes. Structural equation models further confirmed that complex components were transformed into simple components by nutrient and physicochemical factors with decreasing lake depth. This study suggests that changes in environmental conditions with lake depth may result in changes in the quality of HS in lake sediments.

17517. 题目: Unraveling the Reaction Mechanism of Selective C9 Monomeric Phenol Formation from Lignin Using Pd-Al2O3-Activated Biochar Catalyst
文章编号: N21102721
期刊: Bioresource Technology
作者: Lakshmiprasad Gurrala, M. Midhun Kumar, Attada Yerrayya, Prabu Kandasamy, Pedro Castaño, T. Raja, Giovanni Pilloni, Changyub Paek, R. Vinu
更新时间: 2021-10-27
摘要: The conversion of biomass-derived lignin to valuable monomeric phenols at high selectivity is of paramount importance for sustainable biorefineries. In this study, a novel Pd-Al2O3 supported on activated biochar catalyst is developed for lignin hydrogenolysis. The catalyst characterization revealed that the (111) planes of both of Pd0 and Al2O3 were exposed to the surface. The maximum lignin conversion of 70.4% along with high liquid yield (∼57 wt.%) was obtained at 240°C, 3 h and 3 MPa H2 pressure. The total monomeric phenols yield in the liquid was 51.6 wt.%, out of which C9 monomeric guaiacols constituted ∼30.0 wt.% with 38.0% selectivity to 4-propyl guaiacol. Using the reaction intermediate, coniferyl alcohol, chemoselective hydrogenation of Cα=Cβ is proved to occur over the Pd site, while dehydroxylation of Cγ–OH is shown to occur over the alumina site. An impressive carbon atom economy of 60% was achieved for the production of monomeric phenols.

17518. 题目: Particle-size-based elution of petroleum hydrocarbon contaminated soil by surfactant mixture
文章编号: N21102720
期刊: Journal of Environmental Management
作者: Tong Zhang, Jujin Cheng, Hanyue Tan, Shuai Luo, Yuanyuan Liu
更新时间: 2021-10-27
摘要: Surfactants are often used to elute the contaminants from soils in order to remediate the polluted soils. However, the heterogeneity of minerals and organic matters with soil particle size may result in adsorption and precipitation of surfactants and affect the distribution of petroleum hydrocarbons (PHCs). In this work, spiked soil samples and surfactant mixture consisting of Tween 80 (TW80) and sodium dodecyl sulfate were prepared. Results showed that the silt-clay-mixture held the high retention capacity of PHCs, and 30% total petroleum hydrocarbons (TPHs) was retained in the soil fraction of ‘<125 μm’ (high concentration), while 70% TPHs (low concentration) was retained in the soil fraction of ‘>125 μm’. TW80 was highly adsorbed on the montmorillonite and aluminosilicates of the soil, and the adsorption of TW80 in surfactant mixture could be relieved at mass ratio of 1:1. This study provides a novel strategy in the elution removal of PHCs from the contaminated soils, in which with the separation of soil particles by the size of 125 μm before elution, as high as 80% PHCs could be eluted from the soil by surfactant mixture.

17519. 题目: Leveraging high-throughput hyperspectral imaging technology to detect cadmium stress in two leafy green crops and accelerate soil remediation efforts
文章编号: N21102719
期刊: Environmental Pollution
作者: Maria Zea, Augusto Souza, Yang Yang, Linda Lee, Krishna Nemali, Lori Hoagland
更新时间: 2021-10-27
摘要: Cadmium (Cd) is a toxic metal that can accumulate in soils and negatively impact crop as well as human health. Amendments like biochar have potential to address these challenges by reducing Cd bioavailability in soil, though reliance on post-harvest wet chemical methods to quantify Cd uptake have slowed efforts to identify the most effective amendments. Hyperspectral imaging (HSI) is a novel technology that could overcome this limitation by quantifying symptoms of Cd stress while plants are still growing. The goals of this study were to: 1) determine whether HSI can detect Cd stress in two distinct leafy green crops, 2) quantify whether a locally sourced biochar derived from hardwoods can reduce Cd stress and uptake in these crops, and 3) identify vegetative indices (VIs) that best quantify changes in plant stress responses. Experiments were conducted in a tightly controlled automated phenotyping facility that allowed all environmental factors to be kept constant except Cd concentration (0, 5 10 and 15 mg kg−1). Symptoms of Cd stress were stronger in basil (Ocimum basilicum) than kale (Brassica oleracea), and were easier to detect using HSI. Several VIs detected Cd stress in basil, but only the anthocyanin reflectance index (ARI) detected all levels of Cd stress in both crop species. The biochar amendment did reduce Cd uptake, especially at low Cd concentrations in kale which took up more Cd than basil. Again, the ARI index was the most effective in quantifying changes in plant stress mediated by the biochar. These results indicate that the biochar evaluated in this study has potential to reduce Cd bioavailability in soil, and HSI could be further developed to identify rates that can best achieve this benefit. The technology also may be helping in elucidating mechanisms mediating how biochar can influence plant growth and stress responses.

17520. 题目: Meta-analysis of the priming effect on native soil organic carbon in response to glucose amendment across soil depths
文章编号: N21102718
期刊: Plant and Soil
作者: Gokul Gaudel, Megharaj Poudel, Peter Semba Mosongo, Li Xing, Abraham Mulu Oljira, Yuming Zhang, Fiston Bizimana, Binbin Liu, Yuying Wang, Wenxu Dong, Jean Yves Uwamungu, Chunsheng Hu
更新时间: 2021-10-27
摘要: Aims The priming effect (PE) on native soil organic matter induced by exogenous carbon addition influences soil carbon and nutrient cycling across the soil depths. Therefore, this study aimed to explore the effects of exogenous glucose-induced PE on native soil organic carbon (SOC) influenced by soil properties across soil depths, weather factors in different ecosystems and experimental variables. Methods We conducted a meta-analysis of 1231 experimental comparisons from 41 publications to explore the responses of native SOC to stable or radioactive carbon isotope (glucose) addition in laboratory incubation experiments representing various ecosystems and soil depths on the global scale. Results Overall, glucose addition had 110% positive PE on native SOC. The PE was higher in deep soil (197%) and lowest in topsoil (99%). Deep soil contains significantly lower SOC, dissolved organic carbon and microbial biomass carbon and a higher soil carbon/nitrogen ratio than topsoil. The PE positively correlated with soil carbon/nitrogen ratio and glucose addition rate but negatively correlated with microbial biomass carbon, dissolved organic carbon, SOC and incubation duration. Furthermore, PE positively related to mean annual temperature and precipitation in cropland while negatively correlated with mean annual precipitation in grassland ecosystem. Conclusions Low soil nutrients and high carbon/nitrogen ratio is the reason for higher PE in deep soil than topsoil. Furthermore, the experimental variables and weather factors provide a framework for understanding the magnitude and direction of PE on native SOC induced by glucose addition and highlight the need for future integrated approaches of studies on PE.