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22701. 题目: Spatial distribution and pollution assessment of metals in intertidal sediments, Korea
文章编号: N19050911
期刊: Environmental Science and Pollution Research
作者: Dong-Woon Hwang, Pyoung-Joong Kim, Seong-Gil Kim, Chul-In Sun, Byoung-Seol Koh, Sang-Ok Ryu, Tae-Hoon Kim
更新时间: 2019-05-09
摘要: We measured the concentrations of acid volatile sulfide (AVS), chemical oxygen demand (COD), and metals (As, Cd, Cu, Hg, Pb, and Zn) in surface sediments of 74 intertidal sectors along the western and southern coasts of Korea to determine their spatial distribution and pollution status. The concentrations of AVS, COD, and metals were relatively higher in northwestern and southeastern coasts due to human and industrial activities around metropolitan, industrial complexes, and large-scale farms. The results of the sediment quality guidelines and geoaccumulation index for organic matter and metal revealed that almost all intertidal sediments were unpolluted with regard to AVS, COD, Cd, Cu, Hg, Pb, and Zn and some intertidal sediments in northwestern and southeastern coasts were moderately polluted with regard to As. However, the results of pollution load index and ecological risk index for metal showed that intertidal sediments in the southeastern coast are significantly polluted and could have an adverse effect on benthic organisms. Thus, the appropriate management policy and restoration plan for intertidal sectors with high metal pollution level in Korea is necessary to improve the quality of intertidal sediment.
22702. 题目: Revealing the correlation of biomethane generation, DOM fluorescence, and microbial community in the mesophilic co-digestion of chicken manure and sheep manure at different mixture ratio
文章编号: N19050910
期刊: Environmental Science and Pollution Research
作者: Liuying Song, Dunjie Li, Hongli Fang, Xiangyunong Cao, Rutao Liu, Qigui Niu, Yu-You Li
更新时间: 2019-05-09
摘要: Batch co-digestion tests of chicken manure (CM) and sheep manure (SM) at different ratio (Rs/c) were conducted under mesophilic condition (35 °C). Batch kinetic analysis of bioCH4 production, excitation-emission matrix (EEM) fluorescence of dissolved organic matter (DOM), and microbial community were investigated. The well-fitted modified Gompertz model (R2, 0.98–0.99) resulted that the co-digestion markedly improved the methane production rate and shortened the lag phase time. The highest bioCH4 yield of 219.67 mL/gVSadd and maximum production rate of 0.378 mL/gVSadd/h were obtained at an optimum Rs/c of 0.4. Additionally, a significant variation of DOM was detected at the Rs/c of 0.4 with a consistent degradation of soluble microbial byproduct-like and protein-like organics. The positive synergy effects of co-digestion conspicuously enhanced the bioCH4 production efficiency. FI370 and NADH were significantly correlated to Rs/c (p < 0.05). Moreover, the correlations among process indicator, EEM-peaks and different environmental parameters were evaluated by Pearson correlation analysis. The high diversity of acetoclastic methanogens and hydrogenotrophic methanogens in the co-digestion improved the stability of process.
22703. 题目: Effect of Oxalate and Sulfate on Iron-Catalyzed Secondary Brown Carbon Formation
文章编号: N19050909
期刊: Environmental Science & Technology
作者: Aseel Al Nimer, Laura Rocha, Mohammad A. Rahman, Sergey A. Nizkorodov, Hind A. Al-Abadleh
更新时间: 2019-05-09
摘要: Oxalate and sulfate are ubiquitous components of ambient aerosols with a high complexation affinity to iron. However, their effect on iron-driven secondary brown carbon formation in solution from soluble aromatic and aliphatic reagents was not studied. We report masses and hydrodynamic particle sizes of insoluble particles formed from the dark aqueous phase reaction of catechol, guaiacol, fumaric, and muconic acids with Fe(III) in the presence of oxalate or sulfate. Results show that oxalate decreases particle yield in solution from the reaction of Fe(III), with a stronger effect for guaiacol than catechol. For both compounds, the addition of sulfate results in the formation of more polydisperse (0.1–5 μm) and heavier particles than those from control experiments. Reactions with fumaric and muconic acids show that oxalate (not sulfate) and pH are determining factors in the efficiency of particle formation in solution. Polymerization reactions occur readily in the presence of sulfate in solution producing particles with iron-coordinated and/or pore-trapped sulfate anions. The addition of oxalate to the reactions of Fe(III) with all organics, except guaiacol, produced fewer and larger polymeric particles (>0.5 μm). These results imply that even in the presence of competing ligands, the formation of insoluble and colored particles from soluble organic precursors still dominates over the formation of soluble iron complexes.
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22704. 题目: Does dissolved organic matter or solid peat fuel anaerobic respiration in peatlands?
文章编号: N19050908
期刊: Geoderma
作者: Anya M. Hopple, Laurel Pfeifer-Meister, Cassandra A. Zalman, Jason K. Keller, Malak M. Tfaily, Rachel M. Wilson, Jeffrey P. Chanton, Scott D. Bridgham
更新时间: 2019-05-09
摘要: Solid-phase soil organic matter is the largest carbon (C) pool in peatlands and, as such, has long been assumed to be the primary substrate driving anaerobic respiration in these systems. However, radiocarbon data from previous field samples suggest that dissolved organic matter (DOM) plays a key, and often dominant, role in fueling heterotrophic respiration across a variety of peatlands. In this study, we manipulated available C sources under laboratory conditions to empirically determine the primary C source – solid-phase peat or DOM – fueling anaerobic respiration at surface and deep depth increments within two bogs and a poor fen in northern Minnesota. We found that increasing DOM concentration from 0 to 50% during anaerobic incubations significantly increased rates of surface (25–50 cm) methane (CH4) production, but not carbon dioxide (CO2) production, indicating that DOM acts as a primary driver of surface methanogenesis in peatlands. Contrary to our expectations, this response was consistent across all three sites despite differences in plant communities and biogeochemical characteristics. However, we observed no effect of DOM availability on CH4 or CO2 production at deeper depths (75–100 or 150–200 cm). The lack of response of CO2 production to DOM manipulation highlights the sensitivity of surface CH4 production to changes in the DOM pool quality and quantity, which are likely to occur under future climate change scenarios. However, CH4 production in deeper peat appears to be limited by additional factors beyond labile C availability, at least on the timescale of the laboratory incubations.
22705. 题目: Ashes to ashes: Characterization of organic matter in Andosols along a 3400 m elevation transect at Mount Kilimanjaro using analytical pyrolysis
文章编号: N19050907
期刊: CATENA
作者: Joscha N. Becker, Michaela A. Dippold, Andreas Hemp, Yakov Kuzyakov
更新时间: 2019-05-09
摘要: Tropical mountain ecosystems cover a broad variety of climatic and vegetation zones and are global hotspots of biodiversity. These ecosystems are severely threatened by climate and land-use change, which also strongly affect soil properties. Mt. Kilimanjaro, with its large elevation gradient and relatively homogeneous geology of volcanic rocks and ashes, provides a unique opportunity to study and interpret soil organic matter (SOM) responses to climatic changes.Our objectives were to identify key SOM compounds in six elevation zones (covering ecosystems from tropical dry-lowland, through montane forest, up to alpine heathlands) that are affected by the climatic changes along a 3400 m transect, and to relate these SOM changes to ecosystem specific characteristics. The SOM composition in four topsoils (0–10 cm) samples per ecosystem was characterized by analytical double-shot pyrolysis-gas chromatography–mass spectrometry (Py-GC/MS). Evolving-gas analysis-mass spectrometry (EGA-MS) was used to quantitatively compare the thermal desorption (first shot: <280 °C) and pyrolysis step (second shot: 280–600 °C).The percentage of thermally desorbed compounds increased 10 fold from lowland (<900 m) to mountain forest soils (>2000 m), followed by a 40% decrease in alpine ecosystems (>4000 m). Alkanes/-enes/-ols contributed between 4% and 30% to the identified SOM composition, with a maximum at mid elevation (2120 m). Fatty acids and fatty acid esters contributed with <3% to SOM composition and decreased to a minimum of <1% at Podocarpus forest soils (2900 m), followed by a re-increase at higher elevation. The percentage of lignin-derived compounds followed a similar pattern but also responded to reduced woody inputs above the tree line.Two main factors that seem to affect SOM quality and composition at Mt. Kilimanjaro were: 1) the rate and composition of organic matter inputs that in turn are controlled by climatic characteristics and the vegetation type and 2) the decomposition rate and efficiency, mainly controlled by soil pH, temperature and water availability. High forest productivity at mid elevations (2200 m) leads to high amounts of volatile compounds and increases stable SOM pools. The overall carbon accumulation in Andosols of Mt. Kilimanjaro is linked to the percentage of bound lipids (mainly alkanes, alkenes and alcohols), while site specific input patterns (e.g. vegetation or wild fires) are strongly reflected by sterols, lignin derived compounds or polycyclic aromatic compounds in SOM.
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22706. 题目: N-doped graphitic biochars from C-phycocyanin extracted Spirulina residue for catalytic persulfate activation toward nonradical disinfection and organic oxidation
文章编号: N19050906
期刊: Water Research
作者: Shih-Hsin Ho, Yi-di Chen, Ruixiang Li, Chaofan Zhang, Yiming Ge, Guoliang Cao, Ming Ma, Xiaoguang Duan, Shaobin Wang, Nan-qi Ren
更新时间: 2019-05-09
摘要: Biochars are low-cost and environmental-friendly materials, which are promising in wastewater treatment. In this study, biochars were manufactured from C-phycocyanin extracted (C-CP) Spirulina residue (SDBC) via thermal pyrolysis. Simultaneously, N-doping was also achieved from the protein in the algae for obtaining a high-performance carbocatalyst for peroxydisulfate (PDS) activation. The SDBC yielded large specific surface areas, nitrogen loading, and good conductivity, which demonstrated excellent oxidation efficiencies toward a wide array of aqueous microcontaminants. An in-depth mechanistic study was performed by integrating selective radical scavenging, solvent exchange (H2O to D2O), diverse organic probes, and electrochemical measurement, unveiling that SDBC/PDS did not rely on free radicals or singlet oxygen but a nonradical pathway. PDS intimately was bonded with a biochar (SDBC 900-acid, pyrolysis at 900 °C) to form a surface reactive complex that subsequently attacked an organic sulfamethoxazole (SMX) adsorbed on the biochar via an electron-transfer regime. During this process, the SDBC 900-acid played versatile roles in PDS activation, organic accumulation and mediating the electron shuttle from SMX to PDS. This nonradical system can maintain a superior oxidation efficiency in complicated water matrix and long-term stable operation. More importantly, the nonradical species in SDBC 900-acid/PDS system were capable of inactivating the bacteria (Escherichia coli) in wastewater. Therefore, the biochar based nonradical system can provide a mild and high-efficiency strategy for disinfection in waste and drinking water by green carbocatalysis. This study provides not only a value-added biochar catalyst for wastewater purification but also the first insight into the bacteria inactivation via nonradical oxidation.
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22707. 题目: Membrane fouling by the aggregations formed from oppositely charged organic foulants
文章编号: N19050905
期刊: Water Research
作者: Senlin Shao, Wenwen Fu, Xiujuan Li, Danting Shi, Yu Jiang, Jiangyun Li, Tengjing Gong, Xue Li
更新时间: 2019-05-09
摘要: Due to the lack of robust ways to quantify aggregations, fouling of two-foulant aggregations is poorly understood. This work systematically reports the ultrafiltration membrane fouling by aggregations formed from two oppositely charged organic foulants (i.e., humic acid (HA) and lysozyme (LYS)) with the aid of resonance light scattering (RLS) technique. RLS provides an effective approach to detecting the aggregation concentration and reveals that the HA-LYS aggregations were formed at a mass ratio of m(LYS)/m(HA) = 2.77. During the filtration of the mixture of HA and LYS, aggregations over individual foulants were identified to be the main substances deposited on the membrane surface, where the mass of deposition had a good linear relationship with the feed concentration of the aggregations. The HA-LYS aggregations might decrease the total fouling due to their large size, but reduce the fouling reversibility. In the pH range of 5.5–9.2, the pH value had limiting effects on the concentration of HA-LYS aggregations, as well as the consequent fouling. At low ionic strength, the membrane fouling by HA-LYS aggregations decreased as the ionic strength increased due to the reduction of the aggregation concentration. Oppositely, at high ionic strength, this tendency was reversed due to the electrical double layer compression effect. These results suggest that RLS is a simple and effective way to quantify the aggregations of foulants, and the aggregations of foulants have distinct fouling behaviors compared with the individual foulants.
22708. 题目: Characterization of the refractory dissolved organic matters (rDOM) in sludge alkaline fermentation liquid driven denitrification: Effect of HRT on their fate and transformation
文章编号: N19050904
期刊: Water Research
作者: Shenbin Cao, Faqian Sun, Dan Lu, Yan Zhou
更新时间: 2019-05-09
摘要: Enhanced biological denitrification for nitrogen removal using sludge alkaline fermentation liquid (SAFL) as an alternative carbon source has been widely reported in previous studies, while limited studies focused on the degradation of the organics presented in SAFL. In this study, an SAFL driven anoxic denitrification sequencing batch reactor (SBR) was established, the mechanism of organics utilization was characterized and the refractory dissolved organic matters (rDOM) was identified. Denitrification could rapidly proceed with the presence of volatile fatty acids (VFAs) initially, while the denitrification rate largely decreased after the VFAs depleted. A great deal of rDOM, which was hard to be utilized by denitrifying microorganism, was found in the effluent. A prolonged hydraulic retention time (HRT) led to the further transformation of particles and colloids to smaller colloids and soluble organics. Extended HRT promoted the degradation of soluble microbial by-product (SMP), but had minor effect on the removal of humic-like, and fulvic acid-like substances. The characterization of the effluent demonstrated the building blocks, were dominated in the rDOM (43.79%–48.78%), followed by high molecular weight protein (HMW-PN) (13.37%–17.39%), HMW polysaccharide (HMW-PS) (12.84%–15.9%), low molecular weight (LMW) neutrals (11.28%–13.65%), and hydrophobic dissolved organic carbon (HO-DOC) (8.0%–12.62%). Moreover, it was found that the building blocks were relatively easy to be degraded with the extension of HRTs, followed by LMW-PS, LMW-PN, LMW neutrals, HMW-PN, and HMW-PS. However, further extended HRT >24 h could not improve the removal of building blocks, LMW-PS and LMW neutrals. This study, for the first time, provided insights into the transformation of organic matters produced by SAFL in a denitrification system and acted as a guide for the subsequent advanced treatment.
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22709. 题目: Molecular characteristics of dissolved organic matter transformed by O3 and O3/H2O2 treatments and the effects on formation of unknown disinfection by-products
文章编号: N19050903
期刊: Water Research
作者: Phanwatt Phungsai, Futoshi Kurisu, Ikuro Kasuga, Hiroaki Furumai
更新时间: 2019-05-09
摘要: We investigated semiquantitative changes in almost 1,000 dissolved organic matter (DOM) features during oxidation with 1 mg of O3 per liter (mg O3/L), 4 mg O3/L, or 4 mg O3/L + 2.5 mg of H2O2 per liter (advanced oxidation process, AOP) by unknown screening analysis with Orbitrap mass spectrometry. The consequential effects on formation of unknown disinfection by-products (DBPs) by chlorination were evaluated in laboratory-scale experiments. Several hundred unsaturated DOM features with positive oxygen-subtracted double bond equivalents per carbon ((DBE–O)/C) were decomposed by the ozone-only treatment and AOP. The AOP decomposed some saturated (negative (DBE–O)/C)) and reduced molecules, which had negative carbon oxidation states (Cos). Several hundred saturated oxidation by-products were detected after ozonation and the AOP. After chlorination, the samples pre-treated with ozone alone resulted in higher formation of unknown DBPs than the AOP pre-treated sample or the sample without oxidation. Over half of the DBP precursors, estimated by electrophilic substitution, were not totally decomposed by any oxidation process, but they were increased after the ozone-only process and AOP. DBP precursors produced by the ozone-only process or AOP formed unique unknown DBPs. Therefore, post-treatment processes after oxidation and before chlorination are important to minimize formation of unknown DBPs.
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22710. 题目: Efficient phosphorus removal from MBR effluent with heated aluminum oxide particles (HAOPs)
文章编号: N19050902
期刊: Water Research
作者: Gichang Lee, Siamak Modarresi, Mark M. Benjamin
更新时间: 2019-05-09
摘要: Biological processes and chemical precipitation in combination with polishing by granular media or membrane filtration can remove 90–95% of the phosphorus (P) from wastewater. However, reducing the concentration to levels near those in high-quality receiving waters requires additional advanced treatment, typically including adsorption onto specialty media. These processes are often costly, they can be hard to control when the P loading varies, and their effectiveness can be compromised by the presence of competing adsorbates in the water. In this work, a novel process that might mitigate or overcome some of these challenges was explored. In this process, water is treated by passage through micron-sized adsorbent particles (Heated Aluminum Oxide Particles, HAOPs) packed in a layer that is < 1 mm thick, thus combining the attractive features of very small particles with those of flow through packed media.In laboratory tests using both synthetic feed and the effluent from an MBR at a full-scale wastewater treatment plant, the process removed P very efficiently until the HAOPs’ capacity was nearly exhausted, at which point rapid breakthrough of P occurred. The removal capacity was proportional to the thickness of the HAOPs layer and declined by only ∼20% when SO42−, Cl−, and NO3− were all added to the MBR effluent at concentrations of 30 mM (2880, 1065, and 1860 mg/L, respectively). Increasing the solution pH from 7.0 to 8.5 had a similar effect, and increasing the flux of water through the adsorbent layer from 200 to 600 LMH had an even smaller effect (∼10% reduction). In 18 days of continuous pilot-scale operation at the treatment plant, the process performed well, achieving 99.5% P removal steadily during the final seven days of testing, during which the P concentration in the feed ranged from 4 to 9 mg/L. The process also removed 52% of the organic matter in the MBR effluent, as represented by UV254. The sludge generated by the process was extremely easy to dewater and dry.
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22711. 题目: A one-year long survey of temporal disinfection byproducts variations in a consumer's tap and their removals by a point-of-use facility
文章编号: N19050901
期刊: Water Research
作者: Lei Wang, Yi Chen, Shuwei Chen, Liangchen Long, Yinan Bu, Haoyu Xu, Baiyang Chen, Stuart Kranser
更新时间: 2019-05-09
摘要: In order to better understand the occurrence of disinfection byproducts (DBPs) in tap water and their real impacts on consumers, this study made a one-year long survey of the temporal variations of a series of DBPs before and after a point-of-use (POU) treatment facility installed in a building serving for ∼300 people. Water samples were collected every week at a fixed location and time for 1 year, and frequent samplings were carried out every 6 h a day for 1 month at selected seasons, which ultimately amounted to 322 samples. The results show that the concentrations of DBPs were higher in the summer than other seasons, with the lowest DBP levels being observed in spring. Within one week, higher levels of haloacetic acids (HAAs) were identified on weekdays than those on weekends. Diurnally, trihalomethanes, HAAs, and haloacetaldehydes were found to be higher at noon but lower in the evening. Consistent with other studies, the variations of most DBPs were somewhat positively related to the changes of temperature and organic matter, but negatively related to the quantity of free chlorine. With the use of a POU facility, which equips with two activated carbon cartridges and a boiler in sequence, most of DBPs were dramatically reduced, leading to 62–100% lower cytotoxicity for the measured DBPs. The study hence provides a real-water evidence about the DBP occurrences in a typical distribution system endpoint and the efficiency of a typical POU on mitigating DBP risks.
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22712. 题目: Soil properties, microbial communities, and sugarcane yield in paired fields with short- or long-term sugarcane cultivation histories
文章编号: N19050820
期刊: Applied Soil Ecology
作者: Adam F. Bigott, Jeffrey W. Hoy, Lisa M. Fultz
更新时间: 2019-05-08
摘要: Abiotic and biotic factors relationship with microbial ecology and yield decline were evaluated in soils under short- and long-term sugarcane cultivation. Sugarcane yields at paired sites were higher in short-term compared to long-term cultivation soils. Evaluation of soil properties confirmed higher levels of soil organic matter and micro- and macro-nutrients interacting with soil pH and texture in soils with newly cultivated sugarcane production capable of affecting microbial ecology. Depletion of micronutrients, including iron, copper, and zinc, was associated with the long-term cultivation of sugarcane. Soil extracellular enzyme activity was affected by soil nutrient concentrations and cultivation history. Endophytic fungal colonization was more extensive in sugarcane roots from plants grown in long-term cultivation soils. Fatty acid methyl ester (FAME) biomarker profiles in bulk soils exhibited clustering for location and paired soils within locations. Similarity was based on relative abundance of biomarkers for different taxonomic groups under the influence of soil pH, texture, organic matter, and nutrients. FAME biomarker profiles revealed greater cultivation history differences for rhizosphere soils than for bulk soils. The observed patterns for short- and long-term sugarcane cultivation soils would likely influence the structure of the microbial community in the rhizosphere and subsequently influence plant growth. However, there was no consistent pattern for the FAME biomarkers distinguishing long-term from short-term sugarcane cultivation soils. The soil chemical and microbial community results highlight differences between recently and continuously cultivated soils associated with detrimental effects on soil health resulting from long-term sugarcane production.
22713. 题目: Insights into the effect of nickel (Ni(II)) on the performance, microbial enzymatic activity and extracellular polymeric substances of activated sludge
文章编号: N19050819
期刊: Environmental Pollution
作者: Bingrui Ma, Zhiwei Li, Sen Wang, Zhaozhe Liu, Shanshan Li, Zonglian She, Naling Yu, Changkun Zhao, Chunji Jin, Yangguo Zhao, Liang Guo, Mengchun Gao
更新时间: 2019-05-08
摘要: The performance, nitrogen removal rate, microbial enzymatic activity and extracellular polymeric substances (EPS) of activated sludge were assessed under nickel (Ni(II)) stress. The organic matter and NH4+-N removal efficiencies were stable at less than 10 mg/L Ni(II) and subsequently decreased with the increment of Ni(II) concentration from 10 to 30 mg/L. The specific oxygen uptake rate and dehydrogenase activity kept stable at less than 5 mg/L Ni(II) and then declined at 5–30 mg/L Ni(II). Both specific ammonia-oxidizing rate (SAOR) and specific nitrite-oxidizing rate (SNOR) decreased with the increment of Ni(II) concentration. The changing trends of ammonia monooxygenase and nitrite oxidoreductase activities were matched those of SAOR and SNOR, respectively. The nitrite-reducing rate and nitrate-reducing rate illustrated a similar variation tendency to the nitrite reductase activity and nitrate reductase activity, respectively. Ni(II) impacted on the production, chemical composition and functional group of EPS. The relation between the sludge volume index and the EPS production exhibited a better linear function with a negative slope, demonstrating that Ni(II) improved the sludge settleability despite of the increase of EPS production.
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22714. 题目: Assessing the effect of pyrolysis temperature on the molecular properties and copper sorption capacity of a halophyte biochar
文章编号: N19050818
期刊: Environmental Pollution
作者: Jing Wei, Chen Tu, Guodong Yuan, Ying Liu, Dongxue Bi, Liang Xiao, Jian Lu, Benny K.G. Theng, Hailong Wang, Lijuan Zhang, Xiangzhi Zhang
更新时间: 2019-05-08
摘要: The capacity of biochar to take up heavy metals from contaminated soil and water is influenced by the pyrolysis temperature. We have prepared three biochar samples from Jerusalem artichoke stalks (JAS) by pyrolysis at 300, 500 and 700 °C, denoted as JAS300, JAS500, and JAS700, respectively. A variety of synchrotron-based techniques were used to assess the effect of pyrolysis temperature on the molecular properties and copper (Cu) sorption capacity of the samples. The content of oxygen-containing functional groups in the biochar samples decreased, while that of aromatic structures and alkaline mineral components increased, with a rise in pyrolysis temperature. Scanning transmission X-ray microscopy indicated that sorbed Cu(II) was partially reduced to Cu(I), but this process was more evident with JAS300 and JAS700 than with JAS500. Carbon K-edge X-ray absorption near edge structure spectroscopy indicated that Cu(II) cations were sorbed to biochar via complexation and Cu-π bonding. With rising pyrolysis temperature, Cu(II)-complexation weakened while Cu-π bonding was enhanced. In addition, the relatively high ash content and pH of JAS500 and JAS700 facilitated Cu precipitation and the formation of langite on the surface of biochar. The results of this investigation will aid the conversion of halophyte waste to useable biochar for the effective remediation of Cu-contaminated soil and water.
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22715. 题目: Occurrence, distribution, and potential risks of environmental corticosteroids in surface waters from the Pearl River Delta, South China
文章编号: N19050817
期刊: Environmental Pollution
作者: Jian Gong, Canyuan Lin, Xiaoping Xiong, Diyun Chen, Yongheng Chen, Yongshun Zhou, Cuiqin Wu, Yongming Du
更新时间: 2019-05-08
摘要: The occurrence, spatiotemporal distribution, and potential risks of 21 glucocorticoids (GCs) and 3 mineralocorticoids (MCs) in four rivers were studied by investigating the surface waters from the Pearl River Delta (PRD), South China. These environmental corticosteroids (ECs) were commonly present in the river surface waters with average concentrations varying from <0.17 ng/L for fluticasone propionate to 5.6 ng/L for clobetasone butyrate; and cortisone had the highest concentration, 32.9 ng/L. The total ECs ranged in concentration from undetectable to 83.3 ng/L, with a mean and median of 8.1 ng/L and 4.8 ng/L, respectively. Spatially the total EC concentration levels in the Pearl River system occurred in the following order: Zhujiang River (ZR) > Dongjiang River (DR) > Shiziyang waterway (SW) > Beijiang River (BR). These levels generally demonstrated a trend of increasing from upstream to midstream or downstream then attenuating toward the estuary. Considerable seasonal variations in the ECs differed among rivers. Higher ECs concentrations in winter were mostly found in the ZR, whereas lower levels were found in the DR. Moreover, the temporal variations of the ECs were marginal in the BR and SW. These spatiotemporal distributions of the ECs might have been simultaneously influenced by pollution sources derived from anthropogenic activities and river hydrologic conditions. Correlation analyses indicated that dissolved organic carbon (DOC) could play a key role in the occurrence and distribution of ECs in an aquatic environment. Risk assessment demonstrated that the occurrence of ECs might have posed medium to high risk to aquatic organisms in the Pearl River.
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22716. 题目: Paradox in bulk and molecular geochemical data and implications for hydrocarbon migration in the inter-salt lacustrine shale oil reservoir, Qianjiang Formation, Jianghan Basin, central China
文章编号: N19050816
期刊: International Journal of Coal Geology
作者: Xiaoxiao Ma, Maowen Li, Xiongqi Pang, Xueying Wei, Menhui Qian, Guoliang Tao, Peng Liu, Qigui Jiang, Zhiming Li, Yi Zhao, Shiqiang Wu
更新时间: 2019-05-08
摘要: This study analyzes the bulk and molecular geochemical data of 56 core samples of the Eocene Qianjiang Formation, a confined source rock unit embedded with salt intervals formed in a hypersaline lacustrine setting in central China. These source rocks within a single evaporative cycle collected from a recent shale oil exploration well are highly laminated, consisting of both intra- and inter-salt shales. Both organic pores and matrix pores serve as storage for hydrocarbon generated from kerogen within the source rock. Because the contrast in density between kerogen and oil, conversion of kerogen to oil inevitably leads to the increase in pore pressure and oil expulsion from kerogen within the same source rock unit. Impregnation of source rocks by expelled oils from nearby mature source rocks or from the organic-rich laminae within the same source rock units leads to anomalous Rock-Eval pyrolysis data, characterized by an abnormally high S1 peak, a high Production Index (PI), a suppressed Tmax and other anomalies. It is contradictory that both Rock-Eval pyrolysis data and sterane isomerization ratios of the studied inter-salt shale samples indicate strong impact of allochthonous hydrocarbons in the source rocks, whereas most aliphatic biomarker parameters obtained from the solvent extracts of these shales still provide useful information on the vertical variation in organic source input and depositional environment of the host rocks. This study provides insights into the bulk and molecular geochemical data interpretation, particularly in the inter-salt shale oil system evaluation in inferring the prevailing directions and pathways of diagenetic fluid movement and hydrocarbon migration.
22717. 题目: Arsenic mobilization from soils in the presence of herbicides
文章编号: N19050815
期刊: Journal of Environmental Sciences
作者: Yuxuan Jiang, Wen Zhong, Wei Yan, Li Yan
更新时间: 2019-05-08
摘要: Arsenic (As) mobilization in soils is a fundamental step controlling its transport and fate, especially in the presence of the co-existing components. In this study, the effect of two commonly used herbicides, glyphosate (PMG) and dicamba, and two competing ions including phosphate and humic acid, on As desorption and release was investigated using batch and column experiments. The batch kinetics results showed that As desorption in the presence of competing factors conformed to the pseudo-second order kinetics at pH range of 5–9. The impact of phosphate on desorption was greatest, followed by PMG. The competitive effect of dicamba and humic acid was at the same level with electrolyte solution. In situ flow cell ATR-FTIR analysis was performed to explore the mechanism of phosphate and PMG impact on As mobilization. The results showed that PMG promoted As(III) desorption by competiting for available adsorption sites with no change in As(III) complexing structure. On the other hand, phophate changed As(III) surface complexes from bidentate to monodentate structures, exhibiting the most siginficant effect on As(III) desorption. As(V) surface complexes remained unchanged in the presence of PMG and phosphate, implying that the competitive effect for As(V) desorption was primarily determined by the available adsorption sites. Long-term (10 days) soil column experiments suggested that the effect of humic acid on As mobilization became pronounced from 3 days (18 PVs). The insights of this study help us understand the transport and fate of As due to herbicides application.
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22718. 题目: Valorization of glycerol/ethanol-rich wastewater to bioflocculants: recovery, properties, and performance
文章编号: N19050814
期刊: Journal of Hazardous Materials
作者: Victor Ajao, Siti Millah, Maria Cristina Gagliano, Harry Bruning, Huub Rijnaarts, Hardy Temmink
更新时间: 2019-05-08
摘要: Microbial extracellular polymeric substances (EPS) were produced in two membrane bioreactors, each separately treating fresh and saline synthetic wastewater (consisting of glycerol and ethanol), with the purpose of applying them as sustainable bioflocculants. The reactors were operated under nitrogen-rich (COD/N ratios of 5 and 20) and limited (COD/N ratios of 60 and 100) conditions. Under both conditions, high COD removal efficiencies of 87-96 % were achieved. However, nitrogen limitation enhanced EPS production, particularly the polysaccharide fraction. The maximum EPS recovery (g EPS-COD/g CODinfluent) from the fresh wastewater was 54 % and 36 % recovery was obtained from the saline (30 g NaCl/L) wastewater. The biopolymers had molecular weights up to 2.1 MDa and anionic charge densities of 2.3-4.7 meq/g at pH 7. Using kaolin clay suspensions, high flocculation efficiencies of 85-92 % turbidity removal were achieved at EPS dosages below 0.5 mg/g clay. Interestingly, EPS produced under saline conditions proved to be better flocculants in a saline environment than the corresponding freshwater EPS in the same environment. The results demonstrate the potential of glycerol/ethanol-rich wastewater, namely biodiesel/ethanol industrial wastewater, as suitable substrates to produce EPS as effective bioflocculants.
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22719. 题目: Effects of the pyrolysis temperature on the biotoxicity of Phyllostachys pubescens biochar in the aquatic environment
文章编号: N19050813
期刊: Journal of Hazardous Materials
作者: Chao Zhang, Baoqing Shan, Shixin Jiang, Wenzhong Tang
更新时间: 2019-05-08
摘要: The use of biochar as an adsorbent for environmental remediation has been attracting increasing interest. However, biochar can contain contaminants such as polycyclic aromatic hydrocarbons (PAHs) and metals (e.g., Cu, Pb, and Zn). We prepared Phyllostachys pubescens biochars at temperatures between 400 and 700 °C. The biochars were used in bioassays using Vibrio qinghaiensis Q67, Daphnia magna, Pseudokirchneriella subcapitata, and Limnodrilus hoffmeisteri to characterize the toxicities and effects of the biochars. The PAH, Cu, Pb, and Zn contents of the biochars were 8.59–14.67, 1.82–3.26, 1.17–3.53, and 8.76–16.47 mg/kg, respectively. The biochars gave maximum P. subcapitata, D. magna, and V. qinghaiensis Q67 inhibition rates of 6.47%, 6.70%, and 29.87%, respectively. The biochars produced at high pyrolysis temperatures (≥600 °C) had low acute biotoxicities to L. hoffmeisteri and barely affected L. hoffmeisteri biomass, reproduction, and lipid content. The biochars may therefore be suitable for sediment remediation.
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22720. 题目: Insight into the enhanced sludge dewaterability by tannic acid conditioning and pH regulation
文章编号: N19050812
期刊: Science of The Total Environment
作者: Dongdong Ge, Haiping Yuan, Jiamu Xiao, Nanwen Zhu
更新时间: 2019-05-08
摘要: Tannic acid (TA), a phenolic compound, may be considered as a sludge conditioning agent on account of its ability to precipitate protein. In this study, the effectiveness of TA conditioning on enhancing waste activated sludge (WAS) dewatering was investigated at various pH values. The results indicated that with the conditioning of 0.15 mmol TA per gram of total solid (TS), the WAS dewaterability was affected distinctly by the pH regulation. The reductions of 86.8% capillary suction time (CST), 96.3% specific resistance of filtration (SRF), and 23.6% water content (Wc) of dewatered sludge cake were achieved at an optimal pH value of 4.0. Meanwhile, obvious alterations were observed in some aspects like supernatant viscosity, zeta potential, particle size and extracellular polymeric substances (EPS) polymers. Correlation analysis indicated that the proteins in slime EPS and loosely bound EPS dominantly governed sludge dewaterability. Fluorescence quenching analysis indicated that in the range of acidity, the increase of pH value afforded more binding sites of sludge EPS for TA. However, the removal of EPS protein depended on the combined effect of TA conditioning and pH regulation. The findings provided a novel approach and explanation of WAS dewaterability enhancement using organic additive conditioning and pH regulation.
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