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22821. 题目: Nitrogen isotope evidence for expanded ocean suboxia in the early Cenozoic
文章编号: N19042603
期刊: Science
作者: Emma R. Kast, Daniel A. Stolper, Alexandra Auderset, John A. Higgins, Haojia Ren, Xingchen T. Wang, Alfredo Martínez-García, Gerald H. Haug, Daniel M. Sigman
更新时间: 2019-04-26
摘要: The million-year variability of the marine nitrogen cycle is poorly understood. Before 57 million years (Ma) ago, the 15 N/ 14 N ratio (δ 15 N) of foraminifera shell-bound organic matter from three sediment cores was high, indicating expanded water column suboxia and denitrification. Between 57 and 50 Ma ago, δ 15 N declined by 13 to 16 per mil in the North Pacific and by 3 to 8 per mil in the Atlantic. The decline preceded global cooling and appears to have coincided with the early stages of the Asia-India collision. Warm, salty intermediate-depth water forming along the Tethys Sea margins may have caused the expanded suboxia, ending with the collision. From 50 to 35 Ma ago, δ 15 N was lower than modern values, suggesting widespread sedimentary denitrification on broad continental shelves. δ 15 N rose at 35 Ma ago, as ice sheets grew, sea level fell, and continental shelves narrowed.

22822. 题目: Characterizing Properties and Environmental Behaviors of Dissolved Organic Matter Using Two-Dimensional Correlation Spectroscopic Analysis
文章编号: N19042602
期刊: Environmental Science & Technology
作者: Wei Chen, Chun-Ying Teng, Chen Qian, Han-Qing Yu
更新时间: 2019-04-26
摘要: Dissolved organic matter (DOM) exists ubiquitously in environments and plays critical roles in pollutant mitigation, transformation, and organic geochemical cycling. Understanding its properties and environmental behaviors is critically important to develop water treatment processes and environmental remediation strategies. Generalized two-dimensional correlation spectroscopy (2DCOS), which has numerous advantages, including enhancing spectral resolution and discerning specific order of structural change under an external perturbation, could be used as a powerful tool to interpret a wide range of spectroscopic signatures relating to DOM. A suite of spectroscopic signatures, such as UV–vis, fluorescence, infrared, and Raman spectra that can be analyzed by 2DCOS, is able to provide additional structural information hiding behind the conventional one-dimensional spectra. In this article, the most recent advances in 2DCOS applications for analyzing DOM-related environmental processes are reviewed, and the state-of-the-art novel spectroscopic techniques in 2DCOS are highlighted. Furthermore, the main limitations and requirements of current approaches for exploring DOM-related environmental processes and how these limitations and drawbacks can be addressed are explored. Finally, suggestions and new approaches are proposed to significantly advance the development of 2DCOS in analyzing the properties and behaviors of DOM in natural and engineered environments.
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22823. 题目: Effects of size and spacing of basalt fiber carrier media on performance, extracellular polymeric substances and microbial community of hybrid biological reactors
文章编号: N19042601
期刊: Environmental Science: Water Research & Technology
作者: Qian Zhang, Xianlin Liang, Jing Wei, Shan-Wei Li, Xiang Xiao, Zhigang Liu, Xinshan Rong, Zhishui Liang, Zhi-Ren Wu
更新时间: 2019-04-26
摘要: Carrier media play a key role in microbial activity, biomass amount, microbial community and mass transfer, and hence the process performance in biological wastewater treatment. In this work, a green basalt fiber (BF) carrier medium was introduced into hybrid sequencing batch reactors (SBR) to determine the effects of two important engineering parameters (carrier size and spacing) on the wastewater treatment performance. Extracellular polymeric substances (EPS) and deoxyribonucleic acid (DNA) extracted from the BF-based bio-nest were analyzed to give further insight into the mechanisms. The results show that with carrier size of 15.0 cm and spacing of 14.0 cm the reactor had more nitrifying and denitrifying bacteria as well as appropriate protein/polysaccharide ratio (PN/PS), leading to slightly higher removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN) in wastewater. This study on the effects of carrier size and spacing provides implications for bioreactor construction when using BF carrier media in wastewater treatment.

22824. 题目: Assessing Air–Surface Exchange and Fate of Mercury in a Subtropical Forest Using a Novel Passive Exchange-Meter Device
文章编号: N19042520
期刊: Environmental Science & Technology
作者: Hui Zhang, Luca Nizzetto, Xinbin Feng, Katrine Borgå, Jonas Sommar, Xuewu Fu, Hua Zhang, Gan Zhang, Thorjørn Larssen
更新时间: 2019-04-25
摘要: A novel passive exchange meter (EM) device was developed to assess air–surface exchange and leaching of Hg in a forest floor. Flux measurements were carried out in a subtropical forest ecosystem during a full year. Over 40% of the Hg fixed in fresh forest litter was remobilized in less than 60 days in warm and humid conditions as a response to rapid turnover of labile organic matter (OM). A two-block experiment including understory and clearing showed that losses of Hg covaried with seasonal conditions and was significantly affected by forest coverage. The process controlling the bulk loss of total Hg from the litter was volatilization, which typically represented 76–96% of the loss processes (F_loss). The F_loss ranges were 520–1370 and 165–942 ng m^–2 d^–1 in the understory and clearing, respectively. On a yearly basis, deposition of airborne Hg exceeded total losses by a factor of 2.5 in the clearing and 1.5 in the understory. The vegetation litter in this subtropical forest therefore represented a net sink of atmospheric Hg. This study provided a novel approach to Hg air–soil exchange measurements and further insights on the link between Hg remobilization and OM turnover along with its environmental drivers.
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22825. 题目: Tree species identity alters decomposition of understory litter and associated microbial communities: a case study
文章编号: N19042519
期刊: Biology and Fertility of Soils
作者: Šárka Angst, Lenka Harantová, Petr Baldrian, Gerrit Angst, Tomáš Cajthaml, Petra Straková, Jan Blahut, Hana Veselá, Jan Frouz
更新时间: 2019-04-25
摘要: Investigations on how tree species modify decomposition of understory litter have rarely been conducted, although potentially having impacts on soil carbon stocks and stability. The aim of our study was to disentangle the effects different tree species (alder, spruce, oak, and willow) exert on litter decomposition by comparing decomposition patterns and microbial measures (phospholipid fatty acids and microbial DNA) of both tree and understory (Calamagrostis epigejos) litter exposed at the respective tree species stands of a common garden experiment. An initially uniform mass loss of understory litter exposed at the stands suggests that inherent litter quality (assessed by C:N ratios and lignin content) was the major driver in early decomposition. However, in later stages of our experiment, decomposition of understory litter began to differ among the stands, suggesting a delayed tree species effect. Here, differences in microbial community composition caused by tree species identity (e.g., through varying N supply or phenolics leached from low-quality litter) were likely the major determinants affecting the decomposition of understory litter. However, in these advanced decomposition stages, tree species identity only partly altered microbial communities associated with understory litter. These results indicate that the development of microbial communities on understory litter (and its decay) is likely a combined result of inherent chemical composition and tree species identity.

22826. 题目: Long-term effects of biochar amendment on rhizosphere and bulk soil microbial communities in a karst region, southwest China
文章编号: N19042518
期刊: Applied Soil Ecology
作者: Jianzhong Cheng, Xinqing Lee, Yuan Tang, Qinghai Zhang
更新时间: 2019-04-25
摘要: Biochar (BC) addition is widely used in agriculture to condition soils. However, the effects of BC addition on soil microbial community diversity and composition in karstic regions are unclear, especially after long-term application. To address this knowledge-gap, a field experiment was established to examine changes in soil physicochemical properties and microbial communities following six years of BC amendment. BC was applied to calcareous soils in a karstic region of southwestern China at four levels (w/w): 0%, 1.0%, 5.0%, and 10%. Bacterial community composition was then investigated in both the rhizosphere and bulk soils by 16S rRNA gene sequencing on the Illumina MiSeq Platform. BC addition increased soil pH, total carbon (TC), total nitrogen (TN), and total hydrogen (TH) contents in the rhizosphere and bulk soils. In addition, BC amendment was associated with changes in soil bacterial community compositions and diversities, especially at higher BC application levels. The relative abundances of Gemmatimonadetes increased in rhizosphere soils with increasing BC amendment, while those of the Bacteroidetes, Firmicutes, and Cyanobacteria decreased. The relative abundances of Proteobacteria and Chloroflexi increased in bulk soils with increasing BC application levels, while those of the Bacteroidetes and Verrucomicrobia decreased. Canonical correspondence analysis indicated that bacterial community composition was related to soil characteristics including pH, TC, TN, and TH contents in both rhizosphere and bulk soils. Importantly, variations in these soil parameters were closely associated with BC application rates. These results indicate that long-term BC application significantly impacts soil bacterial community characteristics in karstic regions via modulation of soil physiochemical properties.

22827. 题目: Linking plant community composition with the soil C pool, N availability and enzyme activity in boreal peatlands of Northeast China
文章编号: N19042517
期刊: Applied Soil Ecology
作者: Yanyu Song, Changchun Song, Fuxi Shi, Mingquan Wang, Jiusheng Ren, Xianwei Wang, Lei Jiang
更新时间: 2019-04-25
摘要: Plant species composition influences belowground ecosystem function. However, there are few data on the interactive effects of plant diversity and soil function. We surveyed plant species diversity, and determined soil carbon (C), nitrogen (N) fractions and enzyme activity in five peatlands with different vegetation-types. We also investigated the interactions between plant species diversity and richness, and soil biochemical properties. We found a close relationship between plant species diversity and total carbon (TC) in both surface (0–15 cm) and subsoil (15–30 cm) layers. Plant diversity and richness positively correlated with soil dissolved organic carbon (DOC), NH₄⁺-N in both soil layers and subsoil moisture and total nitrogen (TN), as well as topsoil pH. Plant species diversity and richness were also positively correlated with subsoil moisture, pH, protease, acid phosphatase activity and topsoil urease activity. Soil β-glucosidase, invertase, urease, protease, and acid phosphatase activity positively correlated with soil TC, TN, DOC, available N and soil moisture. Our findings demonstrate that plant community diversity is linked with soil C and N turnover through soil enzyme activity. These results will improve our ability to more fully understand the linkages between aboveground and belowground components in peatland ecosystems.

22828. 题目: Organic matter composition and paleoclimatic changes in tropical mountain peatlands currently under grasslands and forest clusters
文章编号: N19042516
期刊: CATENA
作者: Alexandre Christófaro Silva, Maurício Soares Barbosa, Uidemar Morais Barral, Bárbara Pereira Christófaro Silva, José Sebastião Cunha Fernandes, Abraão José Silva Viana, Carlos Victor Mendonça Filho, Diêgo Faustolo Alves Bispo, Cristiano Christófaro, Carla Ragonezi, Luiz Roberto Guimarães Guilherme
更新时间: 2019-04-25
摘要: Tropical peatlands are important ecosystems for Planet Earth, as they store large amounts of carbon and water. A better understanding of the impact of vegetation type and altitude in content, composition, and rate of accumulation of organic matter is key for assessing the current role of such environments. This study evaluated fibric and soluble fractions as well as the lignocellulosic and the isotopic compositions of the peat organic matter from four tropical mountain peatlands located at different altitudes of the Serra do Espinhaço Meridional, state of Minas Gerais, Brazil. The peatlands are currently under grasslands and forest clusters. Samples of peat under both vegetation types were collected and analyzed for organic matter fractions, cellulose, and lignin (van Soest method), as well as carbon and nitrogen isotopes. Different depths were chosen for radiocarbon dating of selected samples. The organic matter of peatlands currently under grasslands and forest clusters presented differences in soluble fractions, lignocellulosic composition, and δ¹³C values. Multivariate analyses allowed grouping the peatlands by altitude and vegetation type. The chronological succession of grassland and forest clusters in tropical mountain peatlands was influenced by altitude and was related to paleoclimatic changes.

22829. 题目: Impact of a river flood on marine water quality and planktonic microbial communities
文章编号: N19042515
期刊: Estuarine, Coastal and Shelf Science
作者: Annamaria Zoppini, Nicoletta Ademollo, Manuel Bensi, Daniela Berto, Lucia Bongiorni, Alessandra Campanelli, Barbara Casentini, Luisa Patrolecco, Stefano Amalfitano
更新时间: 2019-04-25
摘要: Coastal systems represent primary receptors of land-derived nutrients and pollutants, thus playing a crucial role in carbon burial and marine productivity processes. A closer look into potential effects of river floods and following seawater quality modifications is fundamental to specifically explore the links between the marine contamination patterns and the planktonic microbial processes involved in carbon fluxes. Here we investigated the effects of an extreme flood event (8603 m³ s⁻¹) from a large river (Po River, Italy) on the physical and chemical seawater properties, along with the responses of phytoplanktonic and heterotrophic microbial communities to riverine inputs. Following a multidisciplinary oceanographic survey conducted across three sampling transects perpendicular to the Italian coastline, marine waters differently impacted by the river flood could be discriminated according to the variation patterns of relevant seawater properties (i.e., temperature, salinity, dissolved oxygen, total suspended matter). The concentrations of major nutrients and the organic matter composition (i.e., particulate and dissolved organic carbon, stable carbon isotopic composition, chromophoric dissolved organic matter) were significantly higher in waters at high river flood impact levels. The total dissolved organic carbon and the concentrations of selected inorganic and organic pollutants (i.e., heavy metals and polycyclic aromatic hydrocarbons) were unaltered by riverine inputs, showing values similar or lower than those reported at regular flow conditions. Moreover, the phytoplanktonic and heterotrophic microbial communities showed significant changes linked to river flood, as revealed by a net increase of Chlorophyll-b concentrations (related to the occurrence of freshwater algal taxa), higher prokaryotic C production rates, and shorter prokaryotic cell turnover times in highly impacted waters. In conclusion, our results showed that an extreme river flood event could represent a source of energy for the microbial metabolism involved in OM transformation processes, with consequences on the microbially-driven C-flux and to the overall productivity of coastal marine systems.

22830. 题目: Root diameter controls the accumulation of humic substances in decomposing root litter
文章编号: N19042514
期刊: Geoderma
作者: Qun Liu, Liyan Zhuang, Rui Yin, Xiangyin Ni, Chengming You, Kai Yue, Bo Tan, Yang Liu, Li Zhang, Zhenfeng Xu
更新时间: 2019-04-25
摘要: The humification of plant litter is a crucial step for the buildup of soil organic matter in terrestrial ecosystems. Yet, how environmental change and substrate quality affect root humification still remains poorly understood. A two-year litterbag experiment was conducted to assess the root mass remaining and accumulation of humic substances in roots of three diameter classes (0–2, 2–5 and 5–10 mm) of two common subalpine tree species (Picea asperata and Abies faxoniana) at two elevations (3037 m and 3580 m) on the eastern Tibetan Plateau. No significant differences were found between elevation treatments in the concentration of humic substances. Both root mass loss and concentrations of humic substance, humic acid and fulvic acid decreased with increasing root diameter. Both fulvic acid concentration and humification degree declined as root decomposition progressed but humic acid concentration exhibited an opposite trend. Our results reveal that the diameter-associated variations in accumulation of humic substances were substantially stronger than altitudinal and interspecific differences in decomposing root litters. These findings have important implications for carbon sequestration via root humification in the subalpine forests experiencing snow-covered winter.

22831. 题目: Biochar composition-dependent impacts on soil nutrient release, carbon mineralization, and potential environmental risk: A review
文章编号: N19042513
期刊: Journal of Environmental Management
作者: Ali El-Naggar, Ahmed Hamdy El-Naggar, Sabry M. Shaheen, Binoy Sarkar, Scott X. Chang, Daniel C.W. Tsang, Jörg Rinklebe, Yong Sik Ok
更新时间: 2019-04-25
摘要: Biochar application has multiple benefits for soil fertility improvement and climate change mitigation. Biochar can act as a source of nutrients and sequester carbon (C) in the soil. The nutrient release capacity of biochar once applied to the soil varies with the composition of the biochar, which is a function of the feedstock type and pyrolysis condition used for biochar production. Biochar has a crucial influence on soil C mineralization, including its positive or negative priming of microorganisms involved in soil C cycling. However, in various cases, biochar application to the soil may cause negative effects in the soil and the wider environment. For instance, biochar may suppress soil nutrient availability and crop productivity due to the reduction in plant nutrient uptake or reduction in soil C mineralization. Biochar application may also negatively affect environmental quality and human health because of harmful compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins, and dibenzofurans (PCDD/DF). In this review, we discuss the linkage between biochar composition and function, evaluate the role biochar plays in soil fertility improvement and C sequestration, and discuss regulations and concerns regarding biochar's negative environmental impact. We also summarize advancements in biochar production technologies and discuss future challenges and priorities in biochar research.

22832. 题目: Enhanced “contact mechanism” for interaction of extracellular polymeric substances with low-grade copper-bearing sulfide ore in bioleaching by moderately thermophilic Acidithiobacillus caldus
文章编号: N19042512
期刊: Journal of Environmental Management
作者: Zhuangzhuang Huang, Shoushuai Feng, Yanjun Tong, Hailin Yang
更新时间: 2019-04-25
摘要: In order to enhance the “contact mechanism” governing the interaction of extracellular polymeric substances (EPS) with low-grade copper-bearing sulfide ore for the bioleaching of copper, moderately thermophilic Acidithiobacillus caldus was subjected to exogenous intervention with iron and sulfur. The enhancement of the contact mechanism was systematically investigated by evaluating the attached cells/EPS dynamics, intracellular adenosine triphosphate (ATP), cell functional groups, gene transcriptional level, and ore characteristics. Confocal laser scanning microscopy (CLSM) revealed that exogenous intervention with iron and sulfur led to the production of a denser EPS layer and faster adsorption of the attached cells to the ore based on differential fluorescence staining, which indicated enhancement of the “contact mechanism”. The increased intracellular ATP content of the attached cells in the exogenous substrate system provided the required energy for the adsorption processes associated with the “contact mechanism”. Fourier-transform infrared spectroscopic (FTIR) analysis of the attached cells and the ore showed a dramatic shift of the NH and COS peaks (associated with EPS formation), whereas the FTIR peaks of SO and SO42 associated with sulfur metabolism were also significantly influenced. Moreover, reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that the expression of genes related to cellular energy metabolism (nuoB, nuoC, atpE, atpF), sulfur metabolism (sor, sqr, sdo, soxA), biofilm formation (pgaA, pgaB), and cell colonization (acfA, acfB, acfC, acfD) was up-regulated after exogenous intervention, verifying enhancement of the “contact mechanism” at the transcriptional level. In addition, scanning electron microscopy (SEM) indicated more obvious adsorption traces on the ore surface. X-ray diffraction (XRD) indicated the presence of more complex derivatives, such as Fe₃(SO₄)₄, FeSO₄, Fe₂(SO₄)₃, and Cu₂S, which is suggestive of more active iron/sulfur metabolism with addition of the exogenous iron and sulfur. Overall, a model for bioleaching of low-grade copper-bearing sulfide ore by moderately thermophilic A. caldus was constructed. The results of this investigation should provide a guide for similar industrial bioleaching processes.

22833. 题目: Production of tyrosine-like fluorescence and labile chromophoric dissolved organic matter (DOM) and low surface accumulation of low molecular weight-dominated DOM in a productive Antarctic sea
文章编号: N19042511
期刊: Marine Chemistry
作者: Meilian Chen, Jinyoung Jung, Yun Kyung Lee, Tae-Wan Kim, Jin Hur
更新时间: 2019-04-25
摘要: The Antarctic seas play critical roles in global carbon cycling. Yet, little is known about the dissolved organic matter (DOM) characteristics and the dynamics there. Here, we conducted an extensive study on the seawater DOM in the Amundsen Sea in the Pacific sector of the Southern Ocean. We found that low molecular weight fractions quantitatively dominated the DOM composition at the surface of the highly productive Amundsen Sea Polynya with the relative abundance reaching up to ~89%. Moreover, CDOM and tyrosine-like fluorescence generation were observed, with the average values of~2.4–2.6 m⁻¹ (a₂₅₄) and ~0.3 RU, respectively. While there is a net positive accumulation of dissolved organic carbon (DOC) at the ocean's surface, the net accumulation was negative for the chromophoric DOM (CDOM), which suggests a labile nature for the freshly produced CDOM. The estimated net DOC production ratio was only ~9 ± 6%, which was less than the global level (~17%). This finding signified a low surface accumulation of DOM in the austral summer, which is potentially explained by its nonlimiting nutrients, photo- and/or bio-labile nature of produced DOM, and long water residence time.
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22834. 题目: Carbonate thermoluminescence and its implication for marine productivity change during the Permian-Triassic transition
文章编号: N19042510
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Zhipu Qiu, Haijun Song, Chaoyong Hu, Paul B. Wignall, Huyue Song
更新时间: 2019-04-25
摘要: The Permian-Triassic (P-Tr) crisis was the largest mass extinction of the Phanerozoic and eliminated over 90% of marine species. However, the nature of marine productivity changes during the crisis is a matter of on-going debate. Here, thermoluminescence (TL) measurements from 144 bulk carbonate samples from Meishan (South China) show two levels of variation in TL peak intensities at ~270 °C. The first-order variation is characterized by a rapid, nearly three-fold increase. A secondary variation is interpreted to record periodic fluctuations on a Milankovitch scale (~20-kyr rhythm). The periodic variations of TL are negatively correlated with Mn concentrations, suggesting primary productivity is a key factor controlling the TL peak intensity by photo-reduction of particulate Mn in the presence of organic matter. Therefore, the periodic fluctuations of TL were likely controlled by primary productivity changes on orbital timescales. A significant rise of TL peak intensities across the P-Tr boundary represents the rapid increase of dissolved Mn associated with enhanced marine productivity and/or oceanic anoxia.

22835. 题目: Amino-functionalized sewage sludge-derived biochar as sustainable efficient adsorbent for Cu(II) removal
文章编号: N19042509
期刊: Waste Management
作者: Siqi Tang, Ningning Shao, Chunmiao Zheng, Feng Yan, Zuotai Zhang
更新时间: 2019-04-25
摘要: Sludge biochar as promising low-cost adsorbent has increasingly gained interests, but its poor surface functionality severely undermines its adsorption capacity and selectivity. Here a facile amino functionalization strategy was first proposed to enhance the surface functionality of sewage sludge derived biochar (SSDB) via the combination of sol-gel process for mesoporous silica coating and silylation for highly selective removal of Cu(II). The prepared amino-functionalized SSDB showed excellent adsorption capacity of 74.51 mg/g at room temperature, increasing by nearly 118% with regard to the unfunctionalized SSDB, and prominent selectivity (minute separation factor SF_{Co, Ni, Zn/Cu}) toward Cu(II) uptake. Characterizations demonstrated amine groups on the SSDB, the surface density of which reached 1.34 mg/m². The adsorption kinetics of Cu(II) on amino-functionalized SSDB was well described by a pseudo-second order kinetic model while the adsorption isotherm data was well fitted by Sips model. The pH range in which the adsorption preferentially occurred was 3–5. The occurrence of amine group protonation undermined adsorption performance at a pH < 3. These effects of amino-functionalized SSDB toward Cu(II) uptake were a result of the grafted amine groups specifically complexing with Cu(II) in the tetrahedron. Hence, prominent adsorption performance and low-cost feedstock make amino-functionalized SSDB a sustainable adsorbent for Cu(II) removal in water resulting in a cleaner utilization of sewage sludge.
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22836. 题目: Impacts of enhanced microbial-photoreductive and suppressed dark microbial reductive dissolution on the mobility of As and Fe in flooded tailing soils with zinc sulfide
文章编号: N19042508
期刊: Chemical Engineering Journal
作者: Zheng Chen, Guowen Dong, Yibin Chen, Honghui Wang, Shurui Liu, Zhijie Chen, Chenghu Yang, Xu Shang, Randy Dahlgren
更新时间: 2019-04-25
摘要: Semiconducting minerals are ubiquitous in soil and their association with microbes often affects the environment. In this study, the impacts of zinc sulfide (ZnS, used as a model compound for semiconducting sphalerite) on As/Fe mobility of flooded tailing soils under dark and intermittent illumination conditions were elucidated for the first time. Microbial reductive dissolution of As(V) and Fe(III) was more pronounced under intermittent illumination than under dark conditions. In ZnS-amended soils, release of As(III) and Fe(II) was 1.3 and 1.7 times higher, respectively, under intermittent illumination than the highest concentrations released from soils amended with acetate alone under dark conditions (12741.1 ± 714.3 μg/L and 37.9 ± 2.3 mg/L, respectively). However, under dark conditions in ZnS-amended soil, the release of As(III) and Fe(II) was 0.8 and 0.7 times that of the highest concentrations released from soils amended with acetate under dark conditions, respectively. Treatment with ZnS potentially decreased the abundance of several metal-reducing bacteria (e.g., Bacillus, Geobacter, Clostridium, and Desulfitobacterium), which resulted in lower As/Fe reduction than for the acetate alone treatment under dark conditions. However, under intermittent illumination, the excited mineral photoholes were scavenged by humic/fulvic acids, and photoelectrons were synchronously separated and participated in the microbial electron chain. The fortification provided by the photoelectrons subsequently boosted As/Fe reduction, even though there was a lower abundance of metal-reducing bacteria. Hence, this study provides an in-depth understanding of the impacts of semiconducting minerals on the fates of metal pollutants, microbial diversity, and the bioavailability of dissolved organic matter in flooded soils.
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22837. 题目: Fabrication and Environmental Applications of Multifunctional Mixed Metal-Biochar Composites (MMBC) from Red Mud and Lignin Wastes
文章编号: N19042507
期刊: Journal of Hazardous Materials
作者: Dong-Wan Cho, Kwangsuk Yoon, Yongtae Ahn, Yuqing Sun, Daniel C.W. Tsang, Deyi Hou, Yong Sik Ok, Hocheol Song
更新时间: 2019-04-25
摘要: This study fabricated a new and multifunctional mixed metal-biochar composites (MMBC) using the mixture of two abundant industrial wastes, red mud (RM) and lignin, via pyrolysis under N₂ atmosphere, and its ability to treat wastewater containing various contaminants was comprehensively evaluated. A porous structure (BET surface area = 100.8 m² g^-1) was created and metallic Fe was formed in the MMBC owing to reduction of Fe oxides present in RM by lignin decomposition products during pyrolysis at 700 °C, which was closely associated with the transformation of liquid to gaseous pyrogenic products. The potential application of the MMBC was investigated for the removal of heavy metals (Pb(II) and Ni(II)), oxyanions (As(V) and Cr(VI)), dye (methylene blue), and pharmaceutical/personal care products (para-nitrophenol and pCBA). The aluminosilicate mineral, metallic Fe, and porous carbon matrix derived from the incorporation of RM and lignin contributed to the multifunctionality (i.e., adsorption, chemical reduction, and catalytic reaction) of the MMBC. Thus, engineered biochar composites synthesized from selected industrial wastes can be a potential candidate for environmental applications.
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22838. 题目: Tracking Legacy Mercury in the Hackensack River Estuary Using Mercury Stable Isotopes
文章编号: N19042506
期刊: Journal of Hazardous Materials
作者: John R. Reinfelder, Sarah E. Janssen
更新时间: 2019-04-25
摘要: Spatial redistribution of legacy mercury (Hg) contamination in the Hackensack River estuary (New Jersey, USA) was evaluated using mercury stable isotopes. Total Hg varied from 0.06 to 3.8 μg g^-1 in sediment from the tidal Hackensack River and from 15 to 154 µg g^-1 near historically contaminated sites in upper Berry's Creek, a tributary of the Hackensack River. δ²⁰²Hg values for total Hg from Berry's Creek and Hackensack River estuaries varied over a fairly narrow range (-0.44‰ to -0.21‰), but were highest for sediment from upper Berry's Creek. Isotope mixing plots show that residual legacy mercury from upper Berry's Creek is partially diluted by a low concentration and low δ²⁰²Hg pool of mercury associated with low organic matter content sediments similar to those in Newark Bay. Based on an isotope mixing model, we estimate that upper Berry’s Creek contributes 21% to 82% of the mercury in sediments in the Hackensack River estuary and its tidal tributaries, including upstream marsh habitats far from the primary source. Our results show that mercury stable isotopes can be used to track the redistribution of mercury in tidal ecosystems and highlight the potentially large areas which may be affected by legacy mercury contamination in estuaries.
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22839. 题目: Inhibitory effects of dissolved organic matter on erythromycin bioavailability and possible mechanisms
文章编号: N19042505
期刊: Journal of Hazardous Materials
作者: Zhiping Liu, Laura Delgado-Moreno, Zhijiang Lu, Sufen Zhang, Yan He, Xin Gu, Ziyuan Chen, Qingfu Ye, Jay Gan, Wei Wang
更新时间: 2019-04-25
摘要: Macrolides are widely used antibiotics with ubiquitous occurrence in aquatic environments. Unlike many emerging contaminants, macrolides are positively charged on their amine groups and are likely to interact with negative charge groups of dissolved organic matters (DOMs), which may alter macrolide bioaccumulation but yet to be explored. Here we evaluated the effects of different DOM (LeHA, PPHA, SRHA and SRFA) on erythromycin (an important macrolide) bioaccumulation into aquatic biota with ¹⁴C tracing. Results showed that ERY uptake in organisms was significantly inhibited by DOM (P < 0.05). In the presence of DOM at 20 mg L^-1, the averaged equilibrium concentration (C_e) decreased by 28.1-40.6% for zebrafish and 10.9-25.8% for duckweed, corresponding to reductions in the bioconcentration factor (BCF) by 15.9-32.8% and 10.9-18.5%, respectively. Likely due to their higher carboxyl group content, SRHA and SRFA exhibited stronger inhibitory effects than LeHA or PPHA. The possible interactions between ERY and DOM were explored and results suggested that DOM inhibited ERY bioavailability by forming DOM-ERY complexes via ionic bonding of –COO- and ERY⁺, hydrogen bonding and hydrophobic partitioning. This study was the first to report on inhibitory effects of DOM on erythromycin bioavailability and has important implications for better understanding risks of macrolides.
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22840. 题目: Effects of multi-walled carbon nanotubes on metal transformation and natural organic matters in riverine sediment
文章编号: N19042504
期刊: Journal of Hazardous Materials
作者: Piao Xu, Ming Chen, Guangming Zeng, Danlian Huang, Cui Lai, Ziwei Wang, Ming Yan, Zhenzhen Huang, Xiaomin Gong, Biao Song, Tao Li, Abing Duan
更新时间: 2019-04-25
摘要: In this study, pragmatic prospection of multi-walled carbon nanotubes (MWCNTs) is conducted considering their impacts on Cd transformation, microbial activity and natural organic matter (NOM) in sediments. Indeed, dose-dependent of MWCNTs acceleration in Cd sedimentation and immobilization in water-sediment interface has been found. Unexpectedly, even with the reduced Cd bioavailability, high ratios of MWCNTs incorporation led to exacerbated microbial inactivation. Besides, we noted that MWCNTs significantly lowered NOM contents in sediments. Chemical characterization results also demonstrated that high ratios of MWCNTs incorporation reduced the aromaticity, hydrophobicity and humification of fulvic acid (FA) and humic acid (HA) in sediments. The Cd binding results confirmed that quantity and chemical variation of NOM affected their central ability to Cd binding, referring to significant decrease in combined Cd contents. The findings indicated that reduction in humic substances and chemical structure variation might be the important reason attributed to the MWCNTs toxicity. This study provides novel mechanisms understanding the fate of carbon nanotubes considering the balance in environmental benefit and potential risks.
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