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17281. 题目: Dynamics in riverine inorganic and organic carbon based on carbonate weathering coupled with aquatic photosynthesis in a karst catchment, Southwest China
文章编号: N20112810
期刊: Water Research
作者: Ping'an Sun, Shiyi He, Shi Yu, Junbing Pu, Yaqiong Yuan, Cheng Zhang
更新时间: 2020-11-28
摘要: Biochar was utilized to intensify constructed wetland (CW) for further organic and nitrogen removal from secondary wastewater. Four sets of non-aerated biochar amended vertical flow CW (VFCW) were developed to investigate the synergistic effects of biochar and microbes on pollutant removal. Results showed that the average COD and nitrogen removal efficiencies of VFCW1 (with 1% w/w biochar with microbe and plants) achieved 89.1±5.6% and 90.2±3.1% respectively, and their corresponding removal rates of 10.2±0.8 mg-COD/(m3.d) and 3.57±0.3 mg-TN/(m3.d) which were 35 and 52.3% higher than control. The biochar's dissolved organic carbon release in VFCWs indicated that water and acidic media portray the optimum conditions for nitrogen removal. The 16S RNA gene sequencing analysis indicated that in the biochar-amended VFCWs, bacterial phylum Proteobacteria (24.13-51.95%) followed by Chloroflexi (5.64-25.01%), Planctomycetes (8.48-14.43%), Acidobacteria (2.29-11.65%) were abundantly enhanced. Conclusively, incorporating biochar in non-aerated VFCWs is an efficient technique for enhancing nitrogen removal from secondary effluent.

17282. 题目: Removal of natural organic matter by ion exchange: Comparing regenerated and non-regenerated columns
文章编号: N20112809
期刊: Water Research
作者: Michael Edgar, Treavor H. Boyer
更新时间: 2020-11-28
摘要: Dissolved organic matter (DOM) in water has adverse impacts on the water treatment process and is effectively removed by ion exchange (IEX). Some researchers have proposed the term biological ion exchange (BIEX) for the process of continuous DOM removal by ion exchange without the need for chemical regeneration that results in brine waste. Surface water with moderate dissolved organic carbon (DOC) concentrations (4–6 mg/L) and high sulfate concentrations (80 – 120 mg/L) was fed to two regenerated and two non-regenerated columns for 12,500 bed volumes (9 months) with the goal of investigating the effects of chemical and possibly biological regeneration on long-term IEX operation. Chemically regenerated columns achieved between 60 and 80% DOC removal for the entirety of the experiment, while non-regenerated columns achieved steady DOC removal of ~50%. Inorganic ion analysis showed that biological activity had minimal impact on DOC removal, and the main mechanism of removal was secondary IEX between sulfate (SO42−) and fractions of DOC with high affinities for ion exchange. Fluorescence and specific UV absorbance at 254 nm (SUVA 254) data showed that fractions of DOC with higher SUVA 254 values (terrestrial-like fractions) were better removed by secondary IEX than those with lower SUVA 254 values (aquatic/microbial-like fractions). Scanning electron microscopy showed that biofilms on non-regenerated resins covered 5–15% of the resin surface and are composed of numerous species of bacteria with varying functions, with some protozoa present.

17283. 题目: Distinct nature of soil organic carbon pools and indices under nineteen years of rice based crop diversification switched over from uncultivated land in eastern plateau region of India
文章编号: N20112808
期刊: Soil and Tillage Research
作者: Madhumonti Saha, Madhumita Das, Abhijit Sarkar
更新时间: 2020-11-28
摘要: Crop diversification and their impact on soil C pools and C indices in Eastern plateau region of India is yet to be clearly understood. To explore this, a nineteen years field experiment was carried out to identify suitable diversified cropping system of this region with assessing the SOC pool, C and humification indices. Selected cropping systems were, uncultivated grassland (D-0), rice-fallow (D-1), rice-fallow/rice-okra/rice-maize (D-2), rice-fallow/rice-capsicum/rice-mungbean (D-3) and rice-fallow/rice-capsicum/rice-babycorn/rice-groundnut systems (D-4). Total organic carbon (TOC), various fractions of reactive and recalcitrant C pools, humification indices, dehydrogenase activity and carbon management index (CMI) were determined for 0−15, 15−30 and 30−45 cm soil layers. After 19 years of cultivation, SOC content (g kg−1) of the soil was improved by 22.9 % in D-1 system in 0−15 cm soil depth. Depth dynamics revealed decrement of SOC fractions and stocks with increasing soil depth, although minimum decrement has noticed in D-3 and D-4 systems. D-1 system had the highest very labile C (VLC), labile C (LC) stock, whileless labile C (LLC) and humus C (Hum-C) was found to be highest in D-0. In deeper soil layers (30−45 cm), D-4 system had the highest reactive C pool (RP) stock. Percent deviation of RP-C stock under D-4 system had also the lowest across the 45 cm soil profile. D-2, D-3 and D-4 systems had ∼34, 52 and 40 % higher C lability index (CLI) than D-0 in 0−15, 15−30 and 30−45 cm soil depths, respectively. Besides, D-1 system had similar and ∼ 63 % higher CMI value at 0−15 and 15−30 cm, while, ∼76 % higher CMI value was observed in D-4 system at 30−45 cm in respect to the reference. At lower depth, rate of humification and dehydrogenase activity were enriched in D-4 system. Thus D-4 can be considered as efficient agro-ecosystem to maintain temporal soil fertility and soil health. At regional scale, more diversified rice-based cropping system with legumesappears to be more promising cropping practice that sustains SOC with higher rate of humification and microbial activity.

17284. 题目: Adsorption of arsenite to polystyrene microplastics in the presence of humus
文章编号: N20112807
期刊: Environmental Science: Processes & Impacts
作者: Youming Dong, Minling Gao, Weiwen Qiu, Zhengguo Song
更新时间: 2020-11-28
摘要: Polystyrene microplastics (PSMPs) are detrimental in aqueous environments. This study found that humus, mainly comprising humic acid (HA) and fulvic acid (FA), can facilitate the adsorption of As(III) by PSMPs. The phenolic hydroxyl groups provided by HA contribute to the transport of As(III). HA interacts with the PSMPs to form a π complex, providing more sites on the microplastics for As(III) adsorption, while reducing the time required to reach adsorption equilibrium. Increased temperatures in aqueous environments destroy the hydrogen bonds contributing to the adsorption process, thus causing desorption. Increases in pH and ionic strength reduce the adsorption of As(III) by increasing charge repulsion and microplastic agglomeration, and the co-existing NO3− and PO43− ions inhibit the removal of As(III) in the solution. Our combined results indicate that the migration of PSMPs after As(III) adsorption in the presence of HA and FA requires further research attention.

17285. 题目: Simple method to quantify extraneous water and organic matter degradation in sewer networks
文章编号: N20112806
期刊: Environmental Science: Water Research & Technology
作者: Fengle Yang, Xianzhi Zhang, Jinhua Li, Fangming Jin, Baoxue Zhou
更新时间: 2020-11-28
摘要: Extraneous water and COD degradation along sewer networks were quantified by using the balance model of water flow and pollutant loads.

17286. 题目: Drivers of disinfection byproduct formation and speciation in small, chlorinated coastal groundwater systems: relative roles of bromide and organic matter, and the need for improved source water characterization and monitoring
文章编号: N20112805
期刊: Environmental Science: Water Research & Technology
作者: Tessora R. Young, Steve Deem, Jolyn C. Leslie, Virpi Salo-Zieman, Huan He, Michael C. Dodd
更新时间: 2020-11-28
摘要: Numerous small public groundwater systems on coastal islands in Washington State (WA) that are susceptible to seawater intrusion have reported disproportionately high frequencies of regulatory exceedances for halogenated organic DBPs; especially brominated DBPs. Fifteen such systems spread across a ∼1000 km2 study area were monitored quarterly over a year in a collaboration between the WA Department of Health and University of Washington to identify key drivers of these trends, and to develop operational and regulatory recommendations aimed at minimizing DBP formation in these and similar systems in WA and elsewhere. [Br−] alone was not observed to be a strong predictor of DBP formation potentials (DBP-FPs) or speciation for source waters across the study area, likely due to accompanying large variations in [DOC]. However, bromine substitution factors correlated relatively well with [Br−]/[DOC] ratios, highlighting the importance of both [Br−] and [DOC] in governing DBP formation and speciation in coastal groundwaters. Overall DBP-FPs correlated strongly with [DOC], UV absorbance at 254 nm (A254), and selected size exclusion chromatography (SEC) and fluorescence metrics for each groundwater, with A254 a particularly strong surrogate for DOC. This was consistent with high uniformity of DOM properties (confirmed from SUVA254, fluorescence index, PARAFAC components, and SEC chromatograms) across the study area. Specific DBP-FPs (e.g., ∼72 μgTTHM mgC−1) for the source waters were quite high compared to typical groundwaters, pointing to inherently high DOM reactivity as an additional factor in the frequent DBP regulatory exceedances observed for the investigated sites. Measurements also revealed seasonal trends (e.g., in [Br−] and [DOC]) correlated with DBP formation, but not captured by routine regulatory monitoring, as well as widespread inconsistencies in chlorination practices at the studied systems. While such factors and correlations are well established for surface waters, this work provides one of the few examinations incorporating both laboratory and full-scale observations to demonstrate their importance in small, coastal groundwater systems. Based on these findings, WA has adopted a number of changes in its design manual for new groundwater disinfection systems, and is evaluating changes in its disinfection monitoring and DBP programs that may also serve as models for wider implementation.

17287. 题目: Application of Fourier transform ion cyclotron resonance mass spectrometry in deciphering molecular composition of soil organic matter: A review
文章编号: N20112804
期刊: Science of The Total Environment
作者: Xiaoxiao Zhang, Zhonglin Chen, Huo Xiaoyu, Jing Kang, Shenxin Zhao, Yutao Peng, Fengxia Deng, Jimin Shen, Wei Chu
更新时间: 2020-11-28
摘要: Swiftly deciphering soil organic matter (SOM) composition is critical for research on soil degradation and restoration. Recent advances in analytical techniques (e.g., optical methods and mass spectrometry) have expanded our understanding of the composition, origin, and evolution of SOM. In particular, the use of Fourier transform ion cyclotron resonance mass spectrometers (FTICR-MS) makes it possible to interpret SOM compositions at the molecular level. In this review, we discuss extraction, enrichment, and purification methods for SOM using FTICR-MS analysis; summarize ionization techniques, FTICR-MS mechanisms, data analysis methods, and molecular compositions of SOM in different environments (providing new insights into its origin and evolution); and discuss factors affecting its molecular diversity. Our results show that digenesis, combustion, pyrolysis, and biological metabolisms jointly contribute to the molecular diversity of SOM molecules. The SOM thus formed can further undergo photodegradation during transportation from land to fresh water (and subsequently oceans), resulting in the formation of dissolved organic matter (DOM). Better understanding the molecular features of DOM therefore accelerates our understanding of SOM evolution. In addition, we assess the degradation potential of SOM in different environments to better inform soil remediation methods. Finally, we discuss the merits and drawbacks of applying FTICR-MS on the analysis of SOM molecules, along with existing gaps in knowledge, challenges, and new opportunities for research in FTICR-MS applications and SOM identification.

17288. 题目: Study of the Photoinduced Transformations of Sertraline in Aqueous Media
文章编号: N20112803
期刊: Science of The Total Environment
作者: Calza Paola, Jiménez-Holgado Cristina, Coha Marco, Chrimatopoulos Christoforos, Federica dal Bello, Medana Claudio, Sakkas Vasilios
更新时间: 2020-11-28
摘要: In the present study, the photoinduced degradation of the antidepressant drug sertraline under artificial solar radiation was examined. Photolysis was studied under different experimental conditions to explore its photolytic fate in the aqueous environment. Photolytic degradation kinetics were carried out in ultrapure water, wastewater effluent, as well as in the presence of dissolved organic matter (humic acids), bicarbonate and nitrate ions which enabled their assessment on sertraline photo-transformation. The reaction of sertraline with photoactive compounds accelerated sertraline transformation in comparison with direct photolysis. Moreover, TiO2-mediated photocatalytic degradation of sertraline was investigated, and focus was placed on the identification of by-products. As expected, photocatalysis was extremely effective for sertraline degradation. Photocatalytic degradation proceeded through the formation of forty-four transformation products identified by HPLC-HRMS and after 240 min of irradiation total mineralization was achieved. Microtox bioassay (Vibrio fischeri) was employed to assess the ecotoxicity of the photocatalysis-treated solutions and results have indicated that sertraline photo-transformation proceeds through the formation of toxic compounds.

17289. 题目: Environmental-friendly coal gangue-biochar composites reclaiming phosphate from water as a slow-release fertilizer
文章编号: N20112802
期刊: Science of The Total Environment
作者: Bing Wang, Yuena Ma, Xinqing Lee, Pan Wu, Fang Liu, Xueyang Zhang, Ling Li, Miao Chen
更新时间: 2020-11-28
摘要: To solve the problem of limited adsorption efficiency of pristine biochar for phosphate, a novel biochar composite was prepared from different feedstocks and coal gangue by one facile-step pyrolysis method. The effects of pyrolysis temperature, adsorbent dosage, pH of the solution, and coexisting ions on phosphate adsorption were analyzed. The adsorption performance and mechanism of phosphate in water were investigated. The application of the phosphorus-laden (P-laden) composite as slow-release fertilizer was evaluated by a germination test. The results showed that the maximum phosphate adsorption capacity of coal gangue modified oilseed rape straw biochar prepared at 700 °C (CG-OR700) was 7.9 mg/g at pH 4.0, which is 4.6 times that of pristine biochar. The adsorption process can be well fitted by the pseudo-second-order kinetic and Langmuir isotherm adsorption model. The mechanism of phosphate adsorption mainly includes surface precipitation, ligand exchange, and electrostatic attraction. The P-laden biochar can be used as a slow-release fertilizer to promote seed germination and growth. This study shows that the coal gangue modified biochar composite can not only be used to remove phosphate from wastewater, but also be used as a slow-release fertilizer, providing a new way for the phosphorus recovery and resource utilization of solid wastes.

17290. 题目: Land application of sewage sludge biochar: Assessments of soil-plant-human health risks from potentially toxic metals
文章编号: N20112801
期刊: Science of The Total Environment
作者: Jin Zhang, Hanyu Hu, Minyan Wang, Yanan Li, Shengchun Wu, Yucheng Cao, Peng Liang, Jianyun Zhang, Ravi Naidu, Yanju Liu, Yu Bon Man, Ming Hung Wong, Changai Zhang, Shengdao Shan
更新时间: 2020-11-28
摘要: Effects of sewage sludge-derived biochar and its precursor on the accumulation of metals (Cd, Cu, Pb and Zn) in soil and their uptake by plants in a 1-year field experiment involving corn-radish rotation were comparatively studied. The human health risks were assessed, and the safe application period of biochar were estimated. The application of biochar, compares to sewage sludge, significantly enhanced the radish yield (p < 0.05; not corn yield) and significantly reduced the accumulation of metals in both plants (p < 0.05), especially the annual application at ≤ 15 t ha-1. The hazard quotient analyses of the metals showed there were no health risks to humans (Hazard Index < 1) in consuming the edible parts of the both plants. The application of sewage sludge at ≥ 15 t ha-1 resulted in Cd in radish exceeded the threshold for foodstuffs set by China (0.1 mg kg-1). The total contents of Cd, Cu, Pb and Zn in soil increased gradually as the application of sewage sludge or its biochar increased from 7.5 t ha-1 to 30 t ha-1. More metals were found to be introduced to soil by the land application of biochar than by its precursor at the same doses, because the metals were concentrated in biochar during the preparation process. The contamination risk assessment of soil based on the geo-accumulation index, the contamination factor and the pollution load index suggested the application of biochar on farmland should < 15 t ha-1. Therefore, taking into account the yield of and metal concentrations in the radish and corn plants and the contamination risks in soil, it is recommended that the continuous safe application period at an application of 7.5 t ha-1 year-1 of biochar should not exceed 15 years, and that of its precursor sewage sludge should not exceed 17 years.

17291. 题目: Biochar and effective microorganisms promote Sesbania cannabina growth and soil quality in the coastal saline-alkali soil of the Yellow River Delta, China
文章编号: N20112708
期刊: Science of The Total Environment
作者: Qian Cui, Jiangbao Xia, Hongjun Yang, Jingtao Liu, Pengshuai Shao
更新时间: 2020-11-27
摘要: Soil salinization and nutrient deficiency have emerged as the major factors negatively impacting soil quality and primary productivity in the coastal saline-alkali soil of the Yellow River Delta. Biochar has been proposed as an efficient strategy for promoting plant growth and restoring degraded saline-alkali soil. However, knowledge is inadequate regarding the effects of adding Spartina alterniflora-derived biochar alone or in combination with effective microorganisms (EM) on the growth of Sesbania cannabina and soil quality in saline-alkali soil. To enhance this knowledge, a pot experiment with different EM treatments (without EM addition, EM-; with EM addition, EM+) and a gradient of biochar treatments (0%, B0; 0.5%, B1; 1.5%, B2; and 3%, B3; biochar weight/soil weight) was conducted. Our results showed that biochar addition alone and in combination with EM significantly increased seed germination, plant height, stem diameter, total biomass and plant nutrient uptake of S. cannabina. Biochar addition, EM addition and their interaction significantly decreased soil salt content efficiently and increased soil total carbon (TC), total nitrogen (TN), available phosphorus (AP) and available potassium (AK) but had little effect on soil pH. Biochar addition increased soil organic carbon, soil NH4+ and NO3-, microbial biomass carbon, and soil enzyme activities and these effects increased in strength when biochar and EM were present simultaneously. Of the treatments, the EM+B3 treatment had the largest effects in terms of inhibiting salinization, increasing soil fertility, elevating soil nutrients and enzyme activities, and improving plant growth. Moreover, the application of biochar and EM promoted the growth of S. cannabina by enhancing plant nutrient uptake, improving soil fertility (e.g., TN, AP, AK, NH4+ and NO3-), and elevating soil enzyme activities (urease and alkaline phosphatase activity). Overall, the integrated use of an appropriate biochar rate (3%) and EM for coastal saline-alkali soil could be an effective strategy to ameliorate soil salinity, improve soil quality and promote plant productivity.

17292. 题目: A meta-analysis of heavy metal bioavailability response to biochar aging: importance of soil and biochar properties
文章编号: N20112707
期刊: Science of The Total Environment
作者: Chengpeng Yuan, Baolin Gao, Yutao Peng, Xing Gao, Beibei Fan, Qing Chen
更新时间: 2020-11-27
摘要: Biochar has been widely applied to remediate the heavy metal-polluted soils, whereas biochar aging can induce the changes of the biochar physic-chemical properties. Afterwards, the bioavailability of heavy metals (BHM) will vary in soils which likely increase the unstable fractions of heavy metals and the following environmental risks. To explore the biochar aging effects on the BHM changes in responses to the variation of experimental conditions and biochar properties, a meta-analysis for the literatures published before May 2020 was conducted. A sum of 257 independent observations from 22 published papers was obtained. The results from the analysis of boosted regression tree showed that the soil pH was the most important factor influencing the BHM changes in biochar amended soil, followed by soil texture, aging time and biochar pyrolysis temperature. The results of this review showed that the BHM was decreased by 16.9%, 28.7% and 6.4% in weakly acid soil (pH 6.00 - 6.99), coarse- and medium-textured soils, respectively, but increased by 149% and 121% in the alkaline (pH > 8.00) and fine-textured soils. The BHM declined in the soils amended with biochar pyrolyzed at relative high temperature (> 500 °C), and increased during aging in soils amended with biochar pyrolyzed at relatively low temperature (401-500 °C). In terms of diverse immobilized heavy metals, only bioavailable Zn in soil decreased after aging. However, there was no significant changes in Cd, Cu and Pb’s bioavalability. Besides, the BHM was decreased by 18.6% within the short-term (less than one year) biochar aging, while showed inverse trend during the longer aging processes. Besides, the application of lignin-enriched biochar may counteract the positive effects of the biochar aging on BHM. Our works may promote the interpretation of the interference factors on the BHM changes and filled the research gaps on biochar aging process in soils.

17293. 题目: Efficient removal of volatile organic compound by ball-milled biochars from different preparing conditions
文章编号: N20112706
期刊: Journal of Hazardous Materials
作者: Zhicheng Zhuang, Lan Wang, Jingchun Tang
更新时间: 2020-11-27
摘要: Adsorption is an important technology to deal with volatile organic compounds (VOCs), and biochar has attracted much attention as a new type of adsorbent for VOCs. In this study, rice husk, corn stover and pine wood sawdust biochars from different pyrolysis temperatures (300°C, 500°C and 700°C) were synthesized and treated by ball milling. The pristine and ball-milled biochars were used as adsorbents for acetone and toluene removal. Results showed that wood biochar had higher adsorption capacity for VOCs. After ball milling, the BET specific surface area and the oxygen functional group content of biochars increased. With these changes, all the ball-milled biochars showed higher adsorption rate than the pristine biochars. The ball-milled biochars under pyrolysis temperature of 300°C showed the best adsorption performance for acetone (304 mg g-1), which was 1.7- fold greater than that of pristine biochar. Increasing the surface area by ball milling is conducive to the diffusion of hydrophobic VOCs molecules such as toluene to the adsorption sites in the biochar. However, for hydrophilic VOCs such as acetone, higher oxygen functional groups were the main reason for the enhanced adsorption by ball milling. Therefore, ball-milled biochar can be used as a potential adsorbent material in VOCs treatment.

17294. 题目: Canopy mitigates the effects of nitrogen deposition on soil carbon-related processes in a subtropical forest
文章编号: N20112705
期刊: Science of The Total Environment
作者: Xiaofei Lu, Yuanwen Kuang, Linyun Mou, Enqing Hou, Shenglei Fu, Jianlong Li
更新时间: 2020-11-27
摘要: The rapid increases in atmospheric nitrogen (N) deposition have greatly affected the carbon (C) cycles of terrestrial ecosystems. Most studies concerning on the effects of N deposition have simulated N deposition by directly applying N to the understory and have therefore not accounted for the possibility of N absorption, retention, and transformation by the canopy. In this study, we compared the effects of understory addition of N (UN), canopy addition of N (CN) at 25 and 50 kg N ha−1 yr−1, and ambient addition of N (CK) on soil carbon-related processes in a subtropical forest. After seven years of addition, the contribution of new C from litter (Fnew) was more than 2× greater with UN treatments than with CN treatments. UN treatments significantly increased the activity of β-1,4-glucosidase (BG) but reduced the activities of β-1,4-N-acetylglucosaminidase (NAG), polyphenol oxidase (PPO), and peroxidase (PER). CN treatments, in contrast, did not alter the activities of extracellular enzyme. Compared to CN, UN treatments significantly enhanced soil organic carbon (SOC) and mean weight diameter (MWD, represents soil aggregate stability). Differences in the responses of SOC and MWD to CN and UN treatments were positively correlated with Fnew but negatively correlated with the activities of PPO and PER. The results imply that forest canopy mitigates the effects of atmospheric N inputs on SOC, and that conventional understory N addition might overestimate the positive effects of N deposition on forest soil C-related processes. We suggest that CN rather than UN should be used to simulate the effects of atmospheric N deposition on soil C dynamics in subtropical forests.

17295. 题目: Accumulation and influencing factors of novel brominated flame retardants in soil and vegetation from Fildes Peninsula, Antarctica
文章编号: N20112704
期刊: Science of The Total Environment
作者: Siyuan Xiong, Yanfen Hao, Yingming Li, Ruiqiang Yang, Zhiguo Pei, Qinghua Zhang, Guibin Jiang
更新时间: 2020-11-27
摘要: The concentrations and distributions of nine novel brominated flame retardants (NBFRs) were analyzed in soil, lichen (Usnea aurantiaco-atra), and moss (Sanionia uncinata) samples collected from the Chinese Antarctic Great Wall Station and surrounding Fildes Peninsula area in west Antarctica. Total NBFR concentrations ranged from 61.2–225 pg/g dry weight (dw) in soil, 283–1 065 pg/g dw in moss, and 135–401 pg/g dw in lichen, respectively. Decabromodiphenyl ethane (DBDPE) was the dominant NBFR in all samples, accounting for 65.2%, 50.1%, and 72.4% of cumulative NBFR concentration in soil, lichen, and moss, respectively. The concentrations of NBFRs in plant samples were higher than those in soil, which may be related to plant bioaccumulation. Significant log/log-linear correlations (p < 0.05) were found between the concentrations of BEHTEBP and total organic carbon (TOC) in soil, and between DBDPE and lipid content in mosses, indicating that TOC and lipid content potentially affect certain NBFRs in Antarctic soil and moss. This study presents the first report on NBFR contamination in soil and various vegetation in Antarctica.

17296. 题目: Hydrogen peroxide and persulfate activation using UVA-UVB radiation: degradation of estrogenic compounds and application in sewage treatment plant waters
文章编号: N20112703
期刊: Journal of Hazardous Materials
作者: Anaëlle Gabet, Hélène Métivier, Christine de Brauer, Gilles Mailhot, Marcello Brigante
更新时间: 2020-11-27
摘要: In the present work, the degradation of three estrogens (17β-estradiol (E2), estrone (E1) and 17α-ethinylestradiol (EE2)) was investigated under photoactivation of hydrogen peroxide and persulfate. Lab-scale irradiation experiments showed that both UVA and UVB radiations are able to photoactivate the oxidant precursors, although UVB is more efficient to generate radicals and therefore to degrade the targets. The efficiency of both oxidant precursors was investigated showing higher efficiency in the system with persulfate. The pseudo-first order degradation rate constants and the second order rate constants between the hydroxyl or the sulfate radicals and estrogens were measured. In order to evaluate the process efficiency in real treatment conditions, the degradation of the estrogens spiked into sewage treatment plant effluent was studied. Measurements of second order rate constants between the radical and the effluent organic matter by laser flash photolysis allowed to understand the involved quenching mechanisms. A Yeast Estrogen Screen (YES) assay was used to follow the decrease in estrogenic activity during the estrogen degradation. This assay permitted to ensure that the studied processes are not only able to degrade the estrogens but also to remove their estrogenic activity.

17297. 题目: Impact of fertilization with pig slurry on the isotopic composition of nitrate retained in soil and leached to groundwater in agricultural areas
文章编号: N20112702
期刊: Applied Geochemistry
作者: Rosanna Margalef-Marti, Alba Llovet, Raúl Carrey, Angela Ribas, Xavier Domene, Stefania Mattana, Juan Chin-Pampillo, Claudio Mondini, Josep Ma Alcañiz, Albert Soler, Neus Otero
更新时间: 2020-11-27
摘要: The isotopic composition of N and O of nitrate (NO3-) is usually employed to trace its sources of pollution in groundwater. In agricultural areas, the amount of NO3- that reaches the aquifers after fertilization is controlled by different transformation processes that can affect the nitrogen species isotopic composition. Aiming to address the reliability of using isotope tools to trace sources of groundwater NO3-, the goal of this study was to check the effect of fertilization on the isotopic composition of N compounds retained and leached from soils. The concentration and isotopic composition (δ15N and δ18O) of ammonium (NH4+), NO3- and nitrite (NO2-) was characterized after the application of pig slurry in lysimeters containing either soil under fallow (LF) or the same soil continuously cropped and fertilized (LC) during the previous six years. Results showed that the leached NO3- isotopic signature did not directly reflect the isotopic composition of the applied pig slurry. Just after fertilization, nitrification led to lower δ15NNO3 values in soil extracts and leachates (e.g. from +5.9±0.9 ‰ to +3.8±3.1 ‰ in soil extracts of LF lysimeters). These values increased after complete nitrification (+11.5±1.3 ‰) towards the δ15Nbulk of pig slurry (+19.6±0.5 ‰). Later on, due to soil organic matter and plant debris mineralization and subsequent nitrification, values decreased towards the initial δ15NNO3 of soil but remained above them (+8.6±1.0 ‰). Both LF and LC experiments showed a similar trend and the latter ones allowed to reinforce that long-term fertilization with pig slurry can increase the soil δ15NNO3. Concerning the δ18O of NO3- from soil extracts and leachates, it mainly depended on the δ18O of irrigation water and oxygen, after nitrification of NH4+ from pig slurry. Therefore, studies aiming to trace groundwater NO3- pollution sources in rural areas by using an isotopic approach should consider the fertilization history of each setting. Also, analyzing the δ15Nbulk of soil is recommended, since it could mask the isotopic signature of the N applied through fertilization.

17298. 题目: Electron shuttles facilitate anaerobic methane oxidation coupled to nitrous oxide reduction in paddy soil
文章编号: N20112701
期刊: Soil Biology and Biochemistry
作者: Yaohong Zhang, Fangyuan Wang, Zhongjun Jia
更新时间: 2020-11-27
摘要: Anaerobic oxidation of methane (AOM) coupled with simultaneous consumption of nitrous oxide (N2O) has been recently reported, but the underlying coupling mechanism remains unclear. Here, we investigated N2O-mediated AOM in paddy soil under amendment of electron shuttles (anthraquinone-2,6-disulphonate and methylviologen). Sixty-day anaerobic incubation showed that N2O-mediated AOM occurred in paddy soil, and that electron shuttles stimulated AOM coupled to N2O reduction. Approximate 60% of 13CH4-C was converted into soil organic matter in paddy soil during anaerobic oxidation. Our results suggest that electron shuttles may play important roles in mitigating the emission of greenhouse gases (CH4 and N2O) and increasing organic matter in paddy soils.

17299. 题目: Quantification of organic aerosol and brown carbon evolution in fresh wildfire plumes
文章编号: N20112610
期刊: Proceedings of the National Academy of Sciences
作者: Brett B. Palm, Qiaoyun Peng, Carley D. Fredrickson, Ben H. Lee, Lauren A. Garofalo, Matson A. Pothier, Sonia M. Kreidenweis, Delphine K. Farmer, Rudra P. Pokhrel, Yingjie Shen, Shane M. Murphy, Wade Permar, Lu Hu, Teresa L. Campos, Samuel R. Hall, Kirk Ullmann, Xuan Zhang, Frank Flocke, Emily V. Fischer, Joel A. Thornton
更新时间: 2020-11-26
摘要: The evolution of organic aerosol (OA) and brown carbon (BrC) in wildfire plumes, including the relative contributions of primary versus secondary sources, has been uncertain in part because of limited knowledge of the precursor emissions and the chemical environment of smoke plumes. We made airborne measurements of a suite of reactive trace gases, particle composition, and optical properties in fresh western US wildfire smoke in July through August 2018. We use these observations to quantify primary versus secondary sources of biomass-burning OA (BBPOA versus BBSOA) and BrC in wildfire plumes. When a daytime wildfire plume dilutes by a factor of 5 to 10, we estimate that up to one-third of the primary OA has evaporated and subsequently reacted to form BBSOA with near unit yield. The reactions of measured BBSOA precursors contribute only 13 ± 3% of the total BBSOA source, with evaporated BBPOA comprising the rest. We find that oxidation of phenolic compounds contributes the majority of BBSOA from emitted vapors. The corresponding particulate nitrophenolic compounds are estimated to explain 29 ± 15% of average BrC light absorption at 405 nm (BrC Abs 405 ) measured in the first few hours of plume evolution, despite accounting for just 4 ± 2% of average OA mass. These measurements provide quantitative constraints on the role of dilution-driven evaporation of OA and subsequent radical-driven oxidation on the fate of biomass-burning OA and BrC in daytime wildfire plumes and point to the need to understand how processing of nighttime emissions differs.

17300. 题目: Early snowmelt and sea ice breakup enhance algal export in the Beaufort Sea
文章编号: N20112609
期刊: Progress in Oceanography
作者: Gabrielle Nadaï, Eva-Maria Nöthig, Louis Fortier, Catherine Lalande
更新时间: 2020-11-26
摘要: Microalgal cells collected with moored sediment traps deployed during three to five annual cycles at three sites in the Beaufort Sea were identified to investigate variations in the timing, abundance and composition of microalgal fluxes in relation to snow and sea ice cover. The investigation period encompassed two extremes in snow and sea ice conditions: a delayed melt due to an ice rebound in 2013 and a premature snowmelt and sea ice breakup that led to an ice-free Beaufort Sea in 2016. Diatoms dominated the microalgal fluxes, with the pelagic centric diatoms Thalassiosira spp. and the ice-associated pennate diatoms Fragilariopsis spp. consistently collected at the three sites. The export of the ice-obligated algae Nitzschia frigida indicated the release of sea ice algae at the onset of snowmelt. Early snowmelt and sea ice breakup in 2016 contributed to an early start of ice algae release accompanied with early peaks in diatom fluxes and higher diatom and phytoplankton carbon (PPC) fluxes during spring and summer. Conversely, delayed sea ice algae release, low diatom fluxes, and low PPC fluxes were observed when snowmelt and sea ice breakup occurred late over the Mackenzie shelf break. The amount of diatoms exported at ∼100 to 300 m also likely depended on a match or mismatch between algal production and zooplankton grazing. Variations in the snow and sea ice regimes at the regional scale therefore directly impact the timing and magnitude of microalgal export and its contribution to particulate organic carbon flux in the Arctic Ocean. With global warming, the ongoing sea ice reduction in the Arctic Ocean may increase PPC fluxes to the seafloor and potential carbon sequestration at depth.