21. 题目: Influence of granular activated carbon media properties on natural organic matter and disinfection by-product precursor removal from drinking water
期刊: Water Research
作者: D.M. Golea, P. Jarvis, B. Jefferson, G. Moore, S. Sutherland, S.A. Parsons, S.J. Judd
摘要: Operational and financial constraints challenge effective removal of natural organic matter (NOM), and specifically disinfection by-product (DBP) precursors, at remote and/or small sites. Granular activated carbon (GAC) is a widely used treatment option for such locations, due to its relatively low maintenance and process operational simplicity. However, its efficacy is highly dependent on the media capacity for the organic matter, which in turn depends on the media characteristics.The influence of GAC media properties on NOM/DBP precursor removal has been studied using a range of established and emerging media using both batch adsorption tests and rapid small-scale column tests. DBP formation propensity (DBPFP) was measured with reference to trihalomethanes (THMs) and haloacetic acids (HAAs). All GAC media showed no selectivity for specific removal of precursors of regulated DBPs; DBP formation was a simple function of residual dissolved organic carbon (DOC) levels.UV254 was found to be a good surrogate measurement of DBPFP for an untreated water source having a high DOC. Due to the much-reduced concentration of DBP precursors, the correlation was significantly poorer for the coagulation/flocculation-pretreateed water source.Breakthrough curves generated from the microcolumn trials revealed DOC removal and consequent DBP reduction to correlate reasonably well with the prevalence pores in the 5–10 nm range. A 3–6 fold increase in capacity was recorded for a 0.005–0.045 cm3/g change in 5–10 nm-sized pore volume density. No corresponding correlation was evident with other media pore size ranges.
22. 题目: Mechanisms of Pb and/or Zn adsorption by different biochars: Biochar characteristics, stability, and binding energies
期刊: Science of The Total Environment
作者: Man Zhao, Yuan Dai, Miaoyue Zhang, Can Feng, Baojia Qin, Weihua Zhang, Nan Zhao, Yaying Li, Zhuobiao Ni, Zhihong Xu, Daniel C.W. Tsang, Rongliang Qiu
摘要: Biochar has been widely studied as an amendment for use in remediation of water and soil contaminated with heavy metals such as Pb2+ and Zn2+, but the effects of biochar characteristics, including stability, on the competitive adsorption of Pb2+ and Zn2+ by biochars from various sources are incompletely understood. In this work, biochars from three different feedstocks, including rice straw (RS), chicken manure (CM), and sewage sludge (SS), were prepared at two pyrolysis temperatures, 550 and 350 °C, and tested to investigate the influence of their stabilities and other characteristics on their adsorption of Pb2+ and Zn2+ in both single- and binary-metal systems. RS biochar had the highest carbon and hydrogen contents, greatest number of functional groups (e.g., OH and C=C/C=O), highest pH, most negative surface charge, and highest physical stability, and thus the highest adsorption capacity for Pb2+ and Zn2+. Pyrolysis at the higher temperature resulted in a slight decrease in aromatic functional groups on biochar surfaces but higher adsorption capacities for Pb2+ and Zn2+ due to the decreased biochar particle size and increased specific surface area. FTIR, XRD, and XPS analyses indicated that Pb2+ and Zn2+ were absorbed on the biochars primarily via chemical complexation with aromatic functional groups. Quantum chemistry calculations confirmed that these functional groups (e.g., –OH and-COOH) tended to bind more strongly with Pb2+ than with Zn2+ due to the former's lower binding energies, which also accounted for the notable decrease in adsorption of Zn2+ in the presence of Pb2+. In addition, compared to carboxyl groups, hydroxyl groups had smaller binding energies and stronger metal complexation. These findings provide a theoretical basis for improved understanding of potential applications of biochars in environmental remediation.
23. 题目: Monitoring dissolved organic carbon by combining Landsat-8 and Sentinel-2 satellites: Case study in Saginaw River estuary, Lake Huron
期刊: Science of The Total Environment
作者: Jiang Chen, Weining Zhu, Yong Q. Tian, Qian Yu
摘要: Dissolved organic carbon (DOC) in aquatic environments is an important cycled pool of organic matter on the Earth. Satellite remote sensing provides a useful tool to determine spatiotemporal distribution of water quality parameters. Previous DOC remote sensing studies in inland water suffered from either low spatial resolution or low temporal frequency. In this study, we evaluated the potential of jointly using Landsat-8 and Sentinel-2 with high spatial resolution to estimate DOC concentrations in Saginaw River plume regions of Lake Huron. Firstly, CDOM (colored dissolved organic matter) was estimated from images using the known models and then DOC can be derived in terms of the good correlations between DOC and CDOM. The results show that Landsat-8 and Sentinel-2 had acceptable accuracy and good consistency in DOC estimation so that jointly using them can improve the observation frequency. In different seasons from 2013 to 2018, DOC was typically higher in spring and autumn but lower in summer. Monthly spatiotemporal variations of DOC in 2018 were also observed. The image-derived DOC spatiotemporal variations show that DOC was covaried with Saginaw River discharge (r = 0.82) and also weakly and negatively correlated with water temperature (r = −0.6). This study demonstrated that using Landsat-8 and Sentinel-2 together can offer the potential applications for monitoring DOC and water quality dynamic in complex inland water.
24. 题目: Terrestrial loads of dissolved organic matter drive inter-annual carbon flux in subtropical lakes during times of drought
期刊: Science of The Total Environment
作者: Chih-Yu Chiu, John R. Jones, James A. Rusak, Hao-Chi Lin, Keisuke Nakayama, Timothy K. Kratz, Wen-Cheng Liu, Sen-Lin Tang, Jeng-Wei Tsai
摘要: Lentic ecosystems are important agents of local and global carbon cycling, but their contribution varies along gradients of dissolved organic matter (DOM) and productivity. We investigated how contrasting summer and autumn precipitation can shape annual and inter-annual variation in ecosystem carbon (C) flux (gross primary production (GPP), ecosystem respiration (ER), and CO2 efflux) in two subtropical lakes differing substantially in trophic state and water color. Instrumented buoys recorded time series of free-water DO, terrestrial DOM (tDOM), chlorophyll a, water temperature profiles, and meteorological measurements over five years (2009–2011 and 2014–2015). Reduced precipitation caused immediate and prolonged effects on C flux in both lakes. During the drought year (2014) GPP and ER declined by 60 to 80% and both lakes were either CO2 sinks or neutral. In the subsequent wet year (2015), GPP and ER increased by 40 to 110%, and both lakes shifted to strong net CO2 emitters. Higher ecosystem R resulted from larger GPP while higher tDOM contributed to a dramatic increase in dissolved inorganic carbon, which intensified CO2 emission in both lakes. C flux was more responsive in the clear mesotrophic lake, declining by approximately 40% in the cumulative GPP and ER, and increasing by >400% in CO2 efflux whereas changes in the oligotrophic colored lake were more modest (approximately 30% and 300% for metabolic declines and efflux increases, respectively). Temporal variation and magnitude of C flux were governed by tDOM-mediated changes in epilimnetic nutrient levels and hypolimnetic light availability. This study demonstrated terrestrial loads of DOM strongly influence the inter-annual response and sensitivity of ecosystem C flux to variation in inter-annual precipitation. Our findings have important implications for predicting the trend, magnitude, duration, and sensitivity of the response of C flux in subtropical lakes/reservoirs to future changes in precipitation patterns under altered climatic conditions.
25. 题目: Sterol, fatty acid, and lignin biomarkers identify the response of organic matter accumulation in Englebright Lake, California (USA) to climate and human impacts
期刊: Organic Geochemistry
作者: Christina R. Pondell, Elizabeth A. Canuel
摘要: Climate change is one of the biggest challenges facing humankind. Higher temperatures and changes in precipitation will lead to greater frequency of drought, wildfire, and intense storms that will threaten systems already vulnerable to climate and anthropogenic change. These threats will transform carbon delivery across the terrestrial–aquatic interface. This study investigated how anthropogenic activities and climate influence organic carbon delivery using Englebright Lake, a reservoir in California, as a model system. Organic carbon accumulation in three depositional settings (bottomset, foreset, topset) was analyzed using fatty acid, sterol and lignin biomarkers and compared to records of watershed events to determine responses to dam construction, mining impacts and flood events. Concentrations of long chain saturated fatty acids, plant sterols, epi-brassicasterol/brassicasterol and lignin biomarkers increased by an order of magnitude in foreset deposits in response to flood events (p < 0.007 for each biomarker). Hydraulic mining for gold was recorded as near-zero concentrations of terrigenous biomarkers in topset deposits, whereas decreases in diacids coincident with increases in aquatic sterols in bottomset deposits reflected the response to dam construction (p < 0.007 for each biomarker). Organic carbon accumulation was controlled by event magnitude and duration, and climate-driven event signals were up to an order of magnitude larger than anthropogenic-driven event signals. These data demonstrate the importance of understanding the depositional environment because the ability to characterize three different depositional settings in Englebright Lake enabled us to identify the smaller anthropogenic signals that would have been obscured by the much larger response to climate events.
26. 题目: Characterization of water-insoluble oxidative potential of PM2.5 using the dithiothreitol assay
期刊: Atmospheric Environment
作者: Dong Gao, James A. Mulholland, Armistead G. Russell, Rodney J. Weber
摘要: Both water-soluble and insoluble components of ambient particulate matter (PM) have been shown to contribute to the oxidative potential (OP) of PM. In this study, we used the dithiothreitol (DTT) assay to assess the water-soluble (OPWS−DTT) and total OP (OPtotal−DTT) of ambient fine particles (PM2.5), with water-insoluble OP (OPWI−DTT) determined by difference. Ambient PM2.5 filter samples were collected daily during 2017 in urban Atlanta and were analyzed for OP and major PM components. Results from measurements suggested a measurable contribution of water-insoluble components to OPDTT, which comprised on average 20% of total PM OP. Strong seasonal trends were observed in both volume- and mass-normalized OPtotal−DTT and OPWI−DTT, with higher values in the winter than in the summer, possibly driven by biomass burning emission seasonality. Correlation analysis indicated that all forms of OPDTT measurements were related to organic species and metals. OPtotal−DTT and OPWI−DTT were correlated with brown carbon (BrC) and total metals, especially total crustal elements. A multivariate regression model was developed for OPtotal−DTT based on particle composition data. The model suggested that the variability of OPtotal−DTT was primarily affected by BrC, followed by EC, total Cu and an antagonistic interaction between BrC and total Cu.
27. 题目: Co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions
期刊: Environmental Science and Pollution Research
作者: Jingqiao Li, Wenjing Zhang, Yunqi Qin, Xiaofei Li, Shengyu Wu, Juanfen Chai, Shanghai Du
摘要: To investigate co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions, NH4+ was selected as the target contaminant, and silicon and humic acid (HA) were selected as typical organic and inorganic colloids in groundwater. Column experiments were then conducted to investigate the transport of NH4+ colloids under various hydrochemical conditions. The results showed that because of the different properties of colloidal silicon and HA after combining with NH4+, the co-transport mechanism became significantly different. During transport by the NH4+–colloid system, colloidal silicon occupied the adsorption sites on the medium surface to promote the transport of NH4+, while humic acid (HA) increased the number of adsorption sites of the medium to hinder the transport of NH4+. The co-transport of NH4+ and colloids is closely related to hydrochemical conditions. In the presence of HA, competitive adsorption and morphological changes of HA caused NH4+ to be more likely to be transported at a higher ionic strength (IS = 0.05 m, CaCl2) and alkalinity (pH = 9.3). In the presence of colloidal silicon, blocking action caused the facilitated transport to be dependent on higher ionic strength and acidity (pH = 4.5), causing the recovery of NH4+ to improve by 7.99%, 222.25% (stage 1), and 8.63%, respectively. Moreover, transport increases with the colloidal silicon concentrations of 20 mg/L then declines at 40 mg/L, demonstrating that increased concentrations will lead to blocking and particle aggregation, resulting in delayed release in the leaching stage.
28. 题目: Spatially Resolved Organomineral Interactions across a Permafrost Chronosequence
期刊: Environmental Science & Technology
作者: Tyler D. Sowers, Rucha P. Wani, Elizabeth K Coward, Matthew H.H. Fischel, Aaron R. Betts, Thomas A. Douglas, Owen W. Duckworth, Donald L. Sparks
摘要: Permafrost contains a large (1700 Pg C) terrestrial pool of organic matter (OM) that is susceptible to degradation as global temperatures increase. Of particular importance is syngenetic Yedoma permafrost containing high OM content. Reactive iron phases promote stabilizing interactions between OM and soil minerals and this stabilization may be of increasing importance in permafrost as the thawed surface region (active layer) deepens. However, there is limited understanding of Fe and other soil mineral phase associations with OM carbon (C) moieties in permafrost soils. To elucidate the elemental associations involved in organomineral complexation within permafrost systems, soil cores spanning a Pleistocene permafrost chronosequence (19,000, 27,000, and 36,000 years old) were collected from an underground tunnel near Fairbanks, Alaska. Subsamples were analyzed via scanning transmission X-ray microscopy–near edge X-ray absorption fine structure spectroscopy at the nano- to microscale. Amino acid-rich moieties decreased in abundance across the chronosequence. Strong correlations between C and Fe with discrete Fe(III) or Fe(II) regions selectively associated with specific OM moieties were observed. Additionally, Ca coassociated with C through potential cation bridging mechanisms. Results indicate Fe(III), Fe(II), and mixed valence phases associated with OM throughout diverse permafrost environments, suggesting that organomineral complexation is crucial to predict C stability as permafrost systems warm.
29. 题目: Valorization of biomass waste to engineered activated biochar by microwave pyrolysis: Progress, challenges, and future directions
期刊: Chemical Engineering Journal
作者: Shin Ying Foong, Rock Keey Liew, Yafeng Yang, Yoke Wang Cheng, Peter Nai Yuh Yek, Wan Adibah Wan Mahari, Xie Yi Lee, Chai Sean Han, Dai-Viet N. Vo, Quyet Van Le, Mortaza Aghbashlo, Meisam Tabatabaei, Christian Sonne, Wanxi Peng, Su Shiung Lam
摘要: Biomass waste represents the promising surrogate of fossil fuels for energy recovery and valorization into value-added products. Among thermochemical conversion techniques of biomass, pyrolysis appears to be most alluring owing to its low pollutant emission and diverse products formation. The current pyrolysis applications for valorization of biomass waste is reviewed, covering the key concepts, pyrolysis mode, operating parameters and products. To date, existing types of pyrolysis include conventional pyrolysis (poor heat transfer due to non-selective heating), vacuum pyrolysis (lower process temperature because of vacuum), solar pyrolysis (entirely “green” with solar-powered), and a newly touted microwave pyrolysis. In microwave pyrolysis of biomass, the heat transfer is more efficient as the heat is generated within the core of material by the interaction of microwave with biomass. The plausible mechanisms of microwave heating are dipole polarization, ionic conduction and interfacial polarization. The lack of top-tier reactor design is identified as the main obstacle that impedes the commercialization of microwave pyrolysis in biomass recycling. Based on the existing works, it is surmised that microwave pyrolysis of biomass produces solid biochar as a main product. To confront the great market demand of activated biochar, it is proposed that the solid char could be upgraded into engineered activated biochar with desirable properties for wide application in pollution control, catalysis and energy storage. Hence, the production of engineered activated biochar from microwave pyrolysis process and its applications are reviewed and explicitly discussed to fill the research gap, and the key implications for future development are highlighted.
30. 题目: Leaching behavior and potential ecological risk of heavy metals in Southwestern China soils applied with sewage sludge compost under acid precipitation based on lysimeter trials
作者: Guangxia Qi, Yufeng Jia, Wenjie Liu, Yonghong Wei, Bin Du, Wen Fang, Yumei Guo, Fang Guo, Yihui Wu, Qiong Zou, Jianguo Liu
摘要: The ecological risk of heavy metals (HM) resulting from the use of sewage sludge compost (SSC) as an amendment to flower garden soil (FGS) and to abandoned phosphate mine soil (APMS) influenced by acid rain were simulated in lysimeter trials and the potential ecological risk index (PERI) was evaluated with minor modifications. The use of SSC indeed increased the mobility and release of HMs in FGS and APMS under conditions of acid rain. The leaching dynamics of HMs was found to be influenced by Fe/Al oxides and organic matter (OM) in the soil. The application of SSC as a fertilizer to barren APMS dramatically decreased the mobility of Cr, Cu and Pb by 51–56% due to their retention by particulate organic matter, while the leaching of As, Cd and Ni was increased as the result of competition with OM for available Fe/Al oxides (As) and proton-metal exchange reactions that occurred in HM-OM complexes (Cd and Ni). The ecological risk of FGS and APMS resulting from HM migration was actually low (PERI = 0.07–0.12), but the increased potential ecological risk resulting from the use of SSC were estimated to be moderate (a 16.0–33.5% increase in PERI for SSC-amended FGS) or high (a 140% increase in PERI for SSC-amended APMS). Ni, Cd and Cu were identified as the three main HMs responsible for increasing the ecological risk in soil which was mainly composed of fine-grained particles, whereas Cd and As were key ecological risks HMs in soil that was mainly composed of coarse-grained particles.
31. 题目: Experimental warming and precipitation reduction affect the biomass of microbial communities in a Sphagnum peatland
期刊: Ecological Indicators
作者: Anna M. Basińska, Monika K. Reczuga, Maciej Gąbka, Marcin Stróżecki, Dominika Łuców, Mateusz Samson, Marek Urbaniak, Jacek Leśny, Bogdan H. Chojnicki, Daniel Gilbert, Tadeusz Sobczyński, Janusz Olejnik, Hanna Silvennoinen, Radosław Juszczak, Mariusz Lamentowicz
摘要: Due to their unique flora, hydrology and environmental characteristics, peatlands are precious and specific habitats for microorganisms and microscopic animals. Their microbial network structure and their biomass are crucial for peatland carbon cycling, through primary production, as well as decomposition and mineralization of organic matter. Wetlands are one of the ecosystems most at risk from anthropogenic activities and climate change. Most recent scenarios of climate change for Central Europe predict an increase in air temperature and a decrease in annual precipitation. These changes may disturb the biodiversity of aquatic organisms, and the peat carbon sink. Considering the above climatic scenarios, we aimed to: i) assess the response of microbial community biomass to warming and reduced precipitation through the lens of a manipulative experiment in a peatland ecosystem ii) predict how global warming might affect microbial biodiversity on peatlands exposed to warmer temperatures and decreased precipitation conditions. Additionally, we wanted to identify ecological indicators of warming among microorganisms living in Sphagnum peatland. The result of a manipulative experiment carried out at Rzecin peatland (W Poland) suggested that the strongest reduction in microbial biomass was observed in heated plots and plots where heating was combined with a reduction of precipitation. The most pronounced changes were observed in the case of the very abundant mixotrophic testate amoeba Hyalosphenia papilio and cyanobacteria. Shifts in the Sphagnum microbial network can be used as an early warning indicator of peatland warming, especially a decrease in the biomass of important phototrophic microbes living on the Sphagnum capitula, e.g. Hyalosphenia papilio.
32. 题目: Paddy periphyton reduced cadmium accumulation in rice (Oryza sativa) by removing and immobilizing cadmium from the water–soil interface
期刊: Environmental Pollution
作者: Haiying Lu, Yue Dong, Yuanyuan Feng, Yanchao Bai, Xianjin Tang, Yuncong Li, Linzhang Yang, Junzhuo Liu
摘要: Periphyton plays a significant role in heavy metal transfer in wetlands, but its contribution to cadmium (Cd) bioavailability in paddy fields remains largely unexplored. The main aim of this study was to investigate the effect of periphyton on Cd behavior in paddy fields. Periphyton significantly decreased Cd concentrations in paddy waters. Non-invasive micro-test technology analyses indicated that periphyton can absorb Cd from water with a maximum Cd2+ influx rate of 394 pmol cm−2 s−1 and periphyton intrusion significantly increased soil Cd concentrations. However, soil Cd bioavailability declined significantly due to soil pH increase and soil redox potential (Eh) decrease induced by periphyton. With periphyton, more Cd was adsorbed and immobilized on organic matter, carbonates, and iron and manganese oxides in soil. Consequently, Cd content in rice decreased significantly. These findings give insights into Cd biogeochemistry in paddy fields with periphyton, and may provide a novel strategy for reducing Cd accumulation in rice.
33. 题目: Effects of excessive impregnation, magnesium content, and pyrolysis temperature on MgO-coated watermelon rind biochar and its lead removal capacity
期刊: Environmental Research
作者: Jingzhuo Zhang, Deyi Hou, Zhengtao Shen, Fei Jin, David O'Connor, Shizhen Pan, Yong Sik Ok, Daniel C.W. Tsang, Nanthi S. Bolan, Daniel S. Alessi
摘要: MgO-coated watermelon rind biochar (MWRB) is a potentially highly-effective waste-derived material in environmental applications. This research aims to provide valuable insights into the optimization of the production of MWRB for superior environmental performance. It was found that the Mg content of the MWRB could be easily controlled by adjusting the Mg/feedstock mass ratio during excessive impregnation. The BET surface area was found to first increase and then decrease as the Mg content of the MWRB (produced at 600 °C) increased from 1.52% to 10.1%, with an optimal surface area of 293 m2/g observed at 2.51%. Similarly, an optimum pyrolysis temperature of 600 °C was observed in the range of 400–800 °C for a maximum surface area of the MWRB at a fixed Mg/feedstock ratio of 0.48% (resulting in MWRBs with Mg contents of 1.89–2.51%). The Pb removal capacity of the MWRB (produced at 600 °C) increased with increasing Mg content, with a greatest Pb removal capacity of 558 mg/g found for the MWRB with the highest Mg content (10.1%), an improvement of 208% over the 181 mg/g Pb removal capacity of unmodified WRB produced at 600 °C. The Pb removal capacity of the MWRB (produced with 1.89–2.51% Mg) was also discovered to increase from 81.7 mg/g (at 400 °C) to 742 mg/g (at 700 °C), before dropping to 368 mg/g at 800 °C. These findings suggest that the MWRB can be more efficiently utilized in soil and water remediation by optimizing its synthesis conditions.
34. 题目: The influence of corncob-based biochar on remediation of arsenic and cadmium in yellow soil and cinnamon soil
期刊: Science of The Total Environment
作者: Mingke Luo, Hai Lin, Yinhai He, Ye Zhang
摘要: Biochar plays a significant role in soil remediation. However, the simultaneous immobilization mechanism and relationship of biochar to cations and anions have never been clear. We designed a batch incubation experiment to investigate the impact of corncob-based biochars to cadmium (Cd) and arsenic (As) contaminations in yellow soil and cinnamon soil, and analyze the relationships among biochars physicochemical characteristics (surface area: SA, total pore volume: TV, average pore size: AV and the C/O rate), soil properties, metals immobilization and microbial diversity indices. Results showed that the modified biochars (inorganic-modified biochar: BCTD) had a good effect on heavy metals immobilization and transformed acid extractable and reducible fraction into the residual fraction. Total nitrogen, organic matter and available potassium increased in both soils after biochar application. The principal component analysis presented that the smaller C/O rate was favorable to As stabilization; the SA and TV of biochar were negatively correlated with the leaching concentration of Cd. The larger surface area, higher porosity and organic matters of biochar were more beneficial to soil microbial diversity. This work not only can demonstrate remediation mechanisms of heavy metals contaminated soil by biochars, but also gain an application of biochars technology in the recycling and reutilize of agricultural waste, and provide a clear strategy for heavy metals contaminated soil, especially As and Cd.
35. 题目: Changes in soil microbial activity, essential oil quantity, and quality of Thai basil as response to biofertilizers and humic acid
期刊: Journal of Cleaner Production
作者: Anahita Boveiri Dehsheikh, Mohammad Mahmoodi Sourestani, Maryam Zolfaghari, Naeimeh Enayatizamir
摘要: Thai basil (Ocimum basilicum var. thyrsiflorum) is an important medicinal plant that used in pharmaceutical, cosmetic, and food industries. In order to evaluate the effect of biofertilizers and humic acid on secondary metabolites of Thai basil, a factorial experiment; fertilizer treatments (Control, NF (nitrogen-fixing bacterium), PS (phosphate solubilizing bacteria), combination of NF and PS, chemical fertilizer, combination of NF and PS + 50% chemical fertilizer) and humic acid (0 and 20 kg ha−1) was conducted. The soil microbial respiration and carbon biomass, soil organic matter, leaf nitrogen and phosphorus elements, number and size of glandular trichomes as well as the quantity and quality of the essential oil were evaluated. Results showed that the application of biofertilizers greatly caused to increase 60% in soil microbial respiration (1.11 CO2 g−1 dry soil day−1) and 3-fold in carbon biomass (117.47 mg C 100 g−1 dry soil) than control. The use of humic acid enhanced the soil organic matter by 2-fold (1.15%) more than control. The highest value of phosphorus element (0.67%), size of glandular trichomes in upper (411.11 μm2) and lower (419.31 μm2) surfaces, and essential oil content (2.81%) were obtained in the inoculation of plants by PS and the lowest values were observed in control. The combination of NF and PS + 50% chemical fertilizer led to increment 45% in the nitrogen element (3.42%), 1.5-fold in number of glandular trichomes in upper (5.03 number mm−2) and lower (6.22 number mm−2) surfaces and 80% essential oil yield (7.89 g m−2) compared to the control. The maximum amount of methyl chavicol (66.26%), eucalyptol (12.98%), linalool (5.42%), and β-pinene (2.15%) was recorded in combination of NF and PS + 50% chemical fertilizer and the minimum amounts were detected in control. Despite the positive effect of the simultaneous application of humic acid and biofertilizers treatment on the soil organic matter, nitrogen element and some major oil components, humic acid had no significant impact on the phosphorus concentration, size of glandular trichomes and essential oil content and yield. Further investigation is needed to use humic acid in plant nutrition management. In conclusion, combination of NF and PS + 50% chemical fertilizer can be recommended as a suitable solution to reduce the demand for chemical fertilizers and their environmental hazards in warm regions.
36. 题目: Plant-induced insoluble Cd mobilization and Cd redistribution among different rice cultivars
期刊: Journal of Cleaner Production
作者: Xinyang Li, Peiqin Peng, Jian Long, Xia Dong, Kai Jiang, Hongbo Hou
摘要: Selecting rice varieties that adsorb less or more Cd from soil can be respectively applied to safety rice production and phytoremediation. Considering plant-induced Cd mobilization will contribute to the rice cultivar screening. We firstly executed a pot experiment to assess the effect of rice plants on soil Cd forms (BCR method). The results showed that the presence of rice significantly reduced residual-Cd (BCR4) concentrations, indicating the rice plant-induced insoluble Cd mobilization. Subsequent sand culture trial with four rice species (conventional and hybrid low-Cd rice, conventional and hybrid high-Cd rice) and four insoluble Cd compounds (CdS, [Cd3(PO3)2], CdCO3 and CdSe) were conducted to further discuss the interaction between insoluble Cd among different rice varieties. The results showed that rice plants do solubilize soil Cd especially insoluble Cd form due to the interaction among rhizosphere acidification, root secretion of organic matter ligand and other ligands, like phytosiderophore. High-Cd cultivar and hybrid rice cultivar had a greater ability to solubilize the insoluble Cd. Visual MINTEQ predicted that free Cd2+ (∼85.6%) were the dominant Cd speciation of mobilized Cd followed by Cd-DOM complexes (∼7.80%) and other ligand-complexes (∼6.51%) in the rhizosphere solution. Cd bound to protein and pectates and to undissolved phosphate were the major mobilized-Cd chemical forms in rice roots and shoots. In addition, the subcellular analysis suggested that half of mobilized-Cd precipitated in the cell wall of rice root and shoot and the other Cd entranced into the protoplast of rice cell. The fate of rice plant-induced insoluble Cd mobilization could be an indispensable factor in prospective phytoremediation and cleaner rice production.
37. 题目: Efficient removal of refractory organics in landfill leachate concentrates by electrocoagulation in tandem with simultaneous electro-oxidation and in-situ peroxone
期刊: Environmental Research
作者: Ghulam Sarwar Soomro, Chao Qu, Na Ren, Shujuan Meng, Xiaohu Li, Dawei Liang, Shujun Zhang, Yangang Li
摘要: Leachate concentrates, an effluent produced from nanofiltration and/or reverse osmosis, contains a high amount of salts and dissolved organics especially refractory organics. Thus, the treatment of leachate concentrates would consume high energy or a large amount of chemicals. The present study is to develop an effective treatment method by using coupled electrochemical methods with the least possible energy consumption. The leachate concentrates was pretreated by electrocoagulation (EC), with aluminum or iron electrodes as anodes, to decrease the dissolved organic concentration. EC with Al electrode was found to be more efficient by consuming 1.25 kWh/m3 energy to remove 70% of TOC. EC effluent was further subjected to a novel simultaneous electro-oxidation and in-situ peroxone process, which used a Ti-based nickel and antimony doped tin dioxide (NATO) as anode and a carbon nanotubes coated carbon-polytetrafluoroethylene (CNTs-C/PTFE) as cathode for oxygen reduction reaction (ORR). Compared with a traditional EO with cathode for hydrogen evolution reaction (HER-EO), ORR-EO obtained higher efficiency and lower energy consumption of 26.25 kWh/m3, which was much lower than 35.5 kWh/m3 for HER-EO. Results showed that after ORR-EO, a final TOC of 57.3 mg/L was obtained. Thus, EC in tandem with ORR-EO process has an excellent capability and economic merit in the field of treating leachate concentrates.
38. 题目: Susceptible soil organic matter, SOM, fractions to agricultural management practices in salt-affected soils
作者: Mohamed Emran, Serena Doni, Cristina Macci, Grazia Masciandaro, Mohamed Rashad, Maria Gispert
摘要: In the recent decades, soil salinity became the main human-induced soil degradation causes in Egypt’s Nile Delta Valley (ENDV) by affecting the stabilization processes of soil organic matter (SOM). However, soil organic carbon (SOC) is highly conserved by aggregating the stabilized organic molecules under sound agricultural management. In particular, labile SOM fractions assumed to be dually influenced by salinity and agricultural management practices other than the stabilized fractions. This work aimed to study various labile and stable SOM fractions that are more susceptible to the current agricultural practices in salt-affected soils of the ENDV area. Three different agro-ecological sites were studied: Eastern (EH, EM soils) and Western (WM, WL soils) Delta regions dominated by Vertic Torrifluvents, and Coastal region (NCH, NCM soils) dominated by Typic Calcitorrerts of high CaCO3 contents. Two different salinity levels were detected in each site; low in WL soils, medium in WM, NCM, and EM soils, and high in EH and NCH soils. The least values in EM, WL, and NCM soils were due to the recurrent legume applications. The carbon content of glomalin-related soil protein (GRSP) (C-GRSP) was positively correlated with SOC and water-extractable organic carbon (WEOC) fraction confirming the contribution of GRSP to the stabilization of SOM. The lower soil β-glucosidase, phosphatase, and protease enzymes activities were in those soils with larger salinity levels in each site as NCH < NCM, WM < WL, and EH < EM reflecting the effect of soil salinity and CaCO3 contents on soil metabolic activities. Extracted organic carbon (EOC) in both humic and fulvic fractions was higher in EH, WM, WL, and EM soils than in NCH and NCM soils. The chemical composition of SOM obtained by the pyrolysis gas chromatography showed that lignocellulosic and condensed aromatic structures in SOM increased significantly with CaCO3 and salinity. In conclusion, the considered SOM fractions such as WEOC, EOC, GRSP, C-GRSP, together with the pyrolytic results can be considered as significant indicators in the dynamic stability of SOM. Intercropping with legumes may increase the stability of SOM fractions in salt-affected soils of degraded lands. In calcareous soils, severe alteration in SOC conservation was observed and negatively influenced the active constituents of SOM.
39. 题目: Methane emissions and associated microbial activities from paddy salt-affected soil as influenced by biochar and cow manure addition
期刊: Applied Soil Ecology
作者: Binh Thanh Nguyen, Nam Ngoc Trinh, Quang-Vu Bach
摘要: Although previous studies showed that biochar can mitigate methane emissions through microbial activities from paddy fields, little is known about its effects on salt-affected soil. The current study aims to examine the interactive effect of biochar and cow manure (CM) on (1) methane emissions from salt-affected soil and (2) methanogenic and methanotrophic activities to identify potential mechanisms for the emissions. A two-factor pot experiment was set up, following a randomized complete block design with four replicates. Paddy rice (Oryza sativa L.) was grown on six treatments (no CM + no biochar; no CM + rice husk biochar; no CM + rice straw biochar; CM + no biochar; CM + rice husk biochar; CM + rice straw biochar). Methane emissions from salt-affected soil were relatively low and CM addition significantly increased CH4 emissions (by 801%). For the CM treatments, biochar addition significantly reduced methane emissions (by 28 to 680%), but for the non-CM treatments, biochar addition showed no clear effect. The increase in methane emissions by CM could be involved in the improved relative abundance of methanogenic and methanotrophic genes. In contrast, the reduction of methane emissions by biochar was likely related to the reduced abundance of methanogenic and increased that of methanotrophic genes. In brief, low methane emissions from salt-affected soil were increased by CM addition and biochar addition could mitigate the CM's effect. Balancing methanogenic and methanotrophic activities could serve as a major mechanism in determining methane emissions from salt-affected soil added with cow manure and biochar.
40. 题目: Influence of sediment organic carbon on toxicity depends on organism’s trophic ecology
期刊: Environmental Pollution
作者: Mariana Aliceda Ferraz, Rodrigo Brasil Choueri, Ítalo Braga Castro, Cecília Simon da Silva, Fabiane Gallucci
摘要: Studies which showed the influence of organic carbon on the toxicity of sediment-associated contaminants on benthic invertebrates suggest this was primarily due to its influence on the interstitial water concentrations of the contaminant. A higher organic content offers more binding sites for organic contaminants, which means lower toxicity for organisms whose exposure route is mainly through contaminated interstitial water. However, a higher organic content in the sediment could mean a higher toxicity for deposit-feeding organisms, which can assimilate the contaminant by ingestion of contaminated particles. To investigate the influence of sedimentary organic carbon content on the toxicity of an organic contaminant on a benthic community, a microcosm experiment was carried out where natural nematode assemblages were exposed to three concentrations of Irgarol in sediments with two different levels of organic carbon for 7 and 35 days. The response of the nematode assemblage to sediment contamination by Irgarol differed between organically “Lower organic carbon” and “Higher organic carbon” sediments. Responses were genus specific and although community composition was the same in both sediments in the beginning of the assay, contamination by Irgarol affected different genera at each sediment type. Also, the differential amount of organic carbon promoted responses of different functional groups. In Lower organic carbon sediments, contaminated treatments showed lower abundances of the genus Viscosia and the group of predacious nematodes, which were probably affected by an increased availability of Irgarol in the interstitial water in this treatment. In Higher organic carbon sediments, the group of deposit-feeders were mainly affected, suggesting the ingestion of contaminated food as the main route of contamination in this condition. These results indicate that the bioavailability of toxic substances in sediments is not only determined by their partitioning between the different phases of the sediment but also by the organism’s trophic ecology.