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25781. 题目: Pedogenic carbonates archive modern and past precipitation change – a transect study from soils and loess-paleosol sequences from Northern Iran
文章编号: N19121506
期刊: Quaternary International
作者: Farhad Khormali, Ali Shahriari, Amin Ghafarpour, Martin Kehl, Eva Lehndorff, Manfred Frechen
更新时间: 2019-12-15
摘要: Stable carbon and oxygen isotope compositions in soil carbonates and in soil organic matter provide insights into (paleo) climatic conditions, especially in arid and semiarid regions where carbonate is abundant in soils. We here investigate δ¹³C and δ¹⁸O isotope composition of bulk carbonate, pedogenic carbonate nodules and organic carbon from modern soils developed along a precipitation gradient (Entisol, Inceptisol, Mollisol and Alfisol) and paleosols formed within loess units in northern Iran. δ¹³C values of organic carbon in the modern soils ranged from -19.5‰ in the arid and semiarid regions to -24‰ in the more humid regions with forest vegetation. δ¹³C values of bulk carbonate in the modern soils ranged from -12.1‰ at the wettest sites to -0.8‰ at the drier sites and thus, a 550 mm increase in precipitation leads to a ∼ 11 ‰ decrease in δ¹³C values of bulk carbonate. In the modern soils, δ¹³C values of pedogenic carbonate nodules in the semiarid areas show higher values by ∼3-4‰ more than the regions with forest vegetation. Unlike δ¹³C values of pedogenic carbonate nodules the δ¹⁸O values of pedogenic carbonate nodules of modern soils in this study did not display pronounced changes across the sections. The change in δ¹³C of carbonates and organic carbon is consistent with the present above-ground vegetation, consisting of a mosaic of habitats with differences in the proportion of C₃ and C₄ vegetation tending to larger C₄ contribution with increasing aridity. The δ¹³C values of carbonates coupled with climate data of the region confirm seasonal bias in the formation of carbonate nodules in the modern soils seen in studies elsewhere. The δ¹³C values of pedogenic carbonate nodules in the paleosols range from -10‰ in humid areas to -7.2‰ in semiarid areas. The trends in δ¹³C composition in modern soils are also visible in the δ¹³C composition in the paleosols, suggesting that in the foothills of the Alborz and Iranian loess plateau, a precipitation gradient existed also in the last interglacial.

25782. 题目: Synthesis and characterization of a novel magnetic calcium-rich nanocomposite and its remediation behaviour for As(III) and Pb(II) co-contamination in aqueous systems
文章编号: N19121505
期刊: Science of The Total Environment
作者: Tao Chen, Xiangchun Quan, Zehua Ji, Xiuqing Li, Yuansheng Pei
更新时间: 2019-12-15
摘要: Herein, a novel magnetic calcium-rich biochar (MCRB), prepared by loading Fe₃O₄ nanoparticles (Fe₃O₄ NPs) on crab shell-derived biochar, was studied for remediation of arsenic and lead co-contamination. Characteristics of the MCRB demonstrated that Fe₃O₄ NPs adhered on the biochar matrix uniformly. Batch experiments on the effects of pH, contact time and initial concentrations revealed that for both metals, removal by the MCRB was pH-dependent with an optimal pH of 6, and that the MCRB had a strong ability for removing arsenic and lead with maximum removal capacities of 15.8 and 62.4 mg g⁻¹, respectively. The mechanisms of the simultaneous removal of arsenic and lead involved both competitive and synergistic effects. The As(III) addition enhanced Pb(II) removal by 5.4–18.8%, while the presence of Pb(II) suppressed As(III) removal by 5.8–17.8%. Competitive complexation of the two metals with biochar was responsible for the suppression, while the enhancement was due mainly to the formation of the Pb(II)-As(III)-FeO ternary surface complex with As(III) as the bridging molecule. These new insights can further our understanding of the application of MCRB as a potential material for use in the treatment of arsenic and lead co-contamination.
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25783. 题目: Simultaneous reduction of Cr(VI) and oxidization of organic pollutants by rice husk derived biochar and the interactive influences of coexisting Cr(VI)
文章编号: N19121504
期刊: Science of The Total Environment
作者: Kaikai Zhang, Aimal Khan, Peng Sun, Yu Zhang, A. Taraqqi-A-Kamal, Yanrong Zhang
更新时间: 2019-12-15
摘要: In this study, biochar derived from rice husk via one-spot calcination treatment at 550 °C (biochar R550), demonstrated a remarkable efficiency in the simultaneous reduction of Cr(VI) and degradation of organic pollutants. With a low Cr(VI) content (0–0.2 mM) coexisting in the biochar (10 g L⁻¹) system, organic pollutants (1 mM) were mostly degraded via a radical process at pH 3, additionally oxidized by Cr(VI) via an electron transfer mediated by biochar, which ultimately promoted the removal of organic pollutants. While further increasing the Cr(VI) content, the radical degradation of organic pollutants was gradually restrained, but partially replaced by the accelerated oxidization of organics by Cr(VI). On the other hand, the Cr(VI) was mainly reduced to Cr (III) by the functional groups on biochar in the absence of organic pollutants. However, the coexisted organic pollutants could take the place of biochar to reduce Cr(VI), resulting in a slight change of Cr(VI) reduction. Further studies indicated that the defective sites on biochar could enhance the reaction between organic pollutants and Cr(VI). These findings are very much interesting and innovative in the ongoing biochar research and demonstrate a new dimension of biochar potential for detoxification of multiple industrial pollutants containing Cr(VI) and organics.
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25784. 题目: Removal of poly- and perfluoroalkyl substances (PFAS) from water by adsorption: Role of PFAS chain length, effect of organic matter and challenges in adsorbent regeneration
文章编号: N19121503
期刊: Water Research
作者: Erica Gagliano, Massimiliano Sgroi, Pietro P. Falciglia, Federico G.A. Vagliasindi, Paolo Roccaro
更新时间: 2019-12-15
摘要: Poly- and perfluoroalkyl substances (PFAS) are a wide group of environmentally persistent organic compounds of industrial origin, which are of great concern due to their harmful impact on human health and ecosystems. Amongst long-chain PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the most detected in the aquatic environment, even though their use has been limited by recent regulations. Recently, more attention has been posed on the short-chain compounds, due to their use as an alternative to long-chain ones, and to their high mobility in the water bodies. Therefore, short-chain PFAS have been increasingly detected in the environmental compartments. The main process investigated and implemented for PFAS removal is adsorption. However, to date, most adsorption studies have focused on synthetic water.The main objective of this article is to provide a critical review of the recent peer-reviewed studies on the removal of long- and short-chain PFAS by adsorption. Specific objectives are to review 1) the performance of different adsorbents for both long- and short-chain PFAS, 2) the effect of organic matter, and 3) the adsorbent regeneration techniques. Strong anion-exchange resins seem to better remove both long- and short-chain PFAS. However, the adsorption capacity of short-chain PFAS is lower than that observed for long-chain PFAS. Therefore, short-chain PFAS removal is more challenging. Furthermore, the effect of organic matter on PFAS adsorption in water or wastewater under real environmental conditions is overlooked. In most studies high PFAS levels have been often investigated without organic matter presence. The rapid breakthrough of PFAS is also a limiting factor and the regeneration of PFAS exhausted adsorbents is very challenging and needs more research.
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25785. 题目: Effects of chemical pretreatments on microplastic extraction in sewage sludge and their physicochemical characteristics
文章编号: N19121502
期刊: Water Research
作者: Xiaowei Li, Lubei Chen, Yanyan Ji, Man Li, Bin Dong, Guangren Qian, John Zhou, Xiaohu Dai
更新时间: 2019-12-15
摘要: Sewage sludge is a primary pathway for microplastics (MPs) entering into terrestrial ecosystems. However, a standardized method to analyze MP in sludge is lacking due to its high organic matter. This study investigated the extraction efficiency of six MPs in five solid matrices, i.e. sewage sludge, cattle manure, soil, sediment and silicon dioxide. Results show lower extraction efficiency of 87.2% for MPs in sludge compared with that in other matrices, especially polyethylene terephthalate (PET) (only 27.8%). The possible reason was that the presence of extracellular polymeric substances within the sludge hinders the MPs to float. Therefore, five protocols, i.e. hydrogen peroxide (H₂O₂), Fenton, nitric acid (HNO₃), hydrochloric acid (HCl) and sodium hydroxide (NaOH) were used to pretreat the sludge and optimize the MP extraction. The sludge pretreated by H₂O₂, Fenton and 1 M of acids had higher MP extraction efficiency than the raw sludge due to higher extraction of the PET. The MP extraction efficiency in the sludge first increased, and subsequently decreased with the soluble chemical oxygen demand (SCOD) content, implying that moderate dissolution of sludge organic matter is beneficial to the MP extraction. Quantitative analysis of the changes in the MP physicochemical characteristics after the pretreatments indicated that polyamide (PA) and PET are not resistant to acid and alkali treatment, respectively. Principal component analysis shows that the effect of pretreatments on the MPs follows a decreasing sequence: alkali > high concentration of acids > low concentration of acids > H₂O₂ and Fenton. Additionally, the susceptibility of the MPs to the pretreatments follows a decreasing sequence: PET, PA and polymethyl methacrylate (PMMA) > polystyrene (PS) > polyethylene (PE) and polypropylene (PP). The findings supply novel insights into the effect of chemical pretreatments on MP extraction in sewage sludge.
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25786. 题目: Characterization of dissolved organic matter derived from atmospheric dry deposition and its DBP formation
文章编号: N19121501
期刊: Water Research
作者: Jijie He, Feifei Wang, Tiantao Zhao, Shaogang Liu, Wenhai Chu
更新时间: 2019-12-15
摘要: Disinfection by-products (DBPs) precursors can be regarded mainly from the drinking water sources and the water treatment processes. A recent study showed that dissolved organic matter (DOM) in atmosphere is an important precursor source of DBPs through atmospheric wet deposition. However, little information is available on the characteristics of DOM derived from dry deposition particulate matter (PM) and the impact of dry deposition on CX₃R-type DBP formation. This study determined whether dry deposition directly contributed the production of DBPs during chlor (am)ination and investigated the mechanism behind the contribution based on the combination of the resin and membrane for fractionating DOM fractions. The results showed that the hydrophilic fraction (HPI) contributed the most DOM and low molecular weight DOM (<10 kDa) was the main component of HPI. In addition, aromatic proteins and soluble microbial products-like compounds were the dominant fluorescent species in DOM derived from PM, and <10 kDa transphilic was the most abundant. The concentrations of C-DBPs and N-DBPs in disinfected PM solution were trihalomethanes (THMs) > haloacetic acids (HAAs) > haloaldehydes and haloacetamides > haloacetonitriles > halonitromethanes for both chlorination and chloramination. The main contributors of calculated toxicity are transphilic and hydrophobic in chlorination and chloramination respectively. Dry deposition PM was deduced to contribute DOM and DBP formation after chlorination in surface water, especially THMs and HAAs. These results presented herein provide key information for controlling DBPs from the perspectives of atmospheric dry deposition, especially in the case of heavy air pollution.
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25787. 题目: Organic Hydroxy Acids as Highly Oxygenated Molecular (HOM) Tracers for Aged Isoprene Aerosol
文章编号: N19121420
期刊: Environmental Science & Technology
作者: Mohammed Jaoui, Rafal Szmigielski, Klara Nestorowicz, Agata Kolodziejczyk, Kumar Sarang, Krzysztof J. Rudzinski, Anna Konopka, Ewa Bulska, Michael Lewandowski, Tadeusz Edward Kleindienst
更新时间: 2019-12-14
摘要: Highly oxygenated molecules (HOMs) are a class of compounds associated with secondary organic aerosols exhibiting high oxygen to carbon (O:C) ratios and often originating from the oxidation of biogenic compounds. Here, the photooxidation and ozonolysis of isoprene were examined under a range of conditions to identify HOM tracers for aged isoprene aerosol. The HOM tracers were identified as silylated derivatives by gas chromatography–mass spectrometry and by detecting their parent compounds by liquid chromatography–high resolution mass spectrometry. In addition to the previously observed methyltetrols and 2-methylglyceric acid, seven tracer compounds were identified, including 2-methyltartronic acid (MTtA), 2-methylerythronic acid (2MeTrA), 3-methylerythronic acid (3MeTrA), 2-methylthreonic acid (2MTrA), 3-methylthreonic acid (3MTrA), erythro-methyltartaric acid (e-MTA), and threo-methyltartaric acid (t-MTA). The molecular structures were confirmed with authentic standards synthesized in the laboratory. The presence of some of these HOMs in the gas and particle phases simultaneously provides evidence of their gas/particle partitioning. To determine the contributions of aged isoprene products to ambient aerosols, we analyzed ambient PM2.5 samples collected in the southeastern United States in summer 2003 and at two European monitoring stations located in Zielonka and Godów (Poland). Our findings show that methyltartaric acids (MTA) and 2- and 3-methylthreonic acids (and their stereoisomers) are representative of aged isoprene aerosol because they occur both in the laboratory chamber aerosol obtained and in ambient PM2.5. On the basis of gas chromatography–mass spectrometry (GC-MS) analysis, their concentrations were found to range from 0.04 ng for 3-methylthreonic acid to 6.3 ng m–3 for methyltartaric acid at the southeast site in Duke Forest, NC, USA.

25788. 题目: Controls of Land Use and the River Continuum Concept on Dissolved Organic Matter Composition in an Anthropogenically Disturbed Subtropical Watershed
文章编号: N19121419
期刊: Environmental Science & Technology
作者: Jesse Alan Roebuck, Michael Seidel, Thorsten Dittmar, Rudolf Jaffé
更新时间: 2019-12-14
摘要: About 250 Tg of dissolved organic carbon are annually transported from inland waters to coastal systems making rivers a critical link between terrestrial and ocean carbon pools. During transport through fluvial systems, various biogeochemical processes selectively remove or transform labile material, effectively altering the composition of dissolved organic matter (DOM) exported to the ocean. The river continuum concept (RCC) has been historically used as a model to predict the fate and quality of organic matter along a river continuum. However, the conversion of natural landscapes for urban and agricultural practices can also alter the sources and quality of DOM exported from fluvial systems, and the RCC may be significantly limited in predicting DOM quality in anthropogenically impacted watersheds. Here, we studied DOM dynamics in the Altamaha River watershed in Georgia, USA, a fluvial system where headwater streams are highly impacted by anthropogenic activities. The primary goal of this study was to quantitatively assess the importance of both the RCC and land use as environmental drivers controlling DOM composition. Land use was a stronger predictor of spatial variation (∼50%) in DOM composition defined by both excitation–emission matrix–parallel factor analysis (EEM–PARAFAC) and ultrahigh-resolution mass spectrometry. This is compared to an 8% explained variability that can be attributed to the RCC. This study highlights the importance of incorporating land use among other controls into the RCC to better predict the fate and quality of DOM exported from terrestrial to coastal systems.

25789. 题目: Internal Phosphorus Storage in Two Headwater Agricultural Streams in the Lake Erie Basin
文章编号: N19121418
期刊: Environmental Science & Technology
作者: Nadia N. Casillas-Ituarte, Audrey Hucks Sawyer, Kelsey M. Danner, Kevin W. King, Alexandra J. Covault
更新时间: 2019-12-14
摘要: Internal phosphorus (P) in sediments plays an important role in the nutrient dynamics of lakes, sometimes long after external loads have been reduced. Similarly, internal P sources may drive the nutrient dynamics of small agricultural streams that drain to larger rivers and lakes, despite best management practices intended to reduce external P loads from adjacent fields. Here, internal P concentrations were measured with sequential extraction on cores collected in spring and summer from two small agricultural streams in the drainage basin of Lake Erie, a large, eutrophic lake experiencing increasing SRP loads. Average total extractable P concentrations were similar to within 5% during spring and summer, but mobile P binding fractions nearly doubled in summer, possibly due to accelerated rates of organic matter mineralization or iron reduction beneath suboxic, stagnant surface waters. One site had chronically greater internal P concentrations by 25–75%, despite the implementation of best management practices such as grass buffers. The site also had more aquatic vegetation that restricted the flow, less dissolved oxygen in surface water, and greater organic matter in sediments during both seasons, suggesting that variations in hydrology, sediment composition, and vegetation influence hot spots of P retention throughout small agricultural streams.

25790. 题目: The optical properties in alkali-soluble fractions extracted from newly shed litters in a subalpine forest
文章编号: N19121417
期刊: Journal of Soils and Sediments
作者: Jiaping Yang, Yu Zhang, Ziyi Liang, Kai Yue, Changkun Fu, Xiangyin Ni, Fuzhong Wu
更新时间: 2019-12-14
摘要: Purpose: Humification of plant detritus is an important pathway for soil organic matter formation. The long-standing studies considered that humification proceeds at very late stages of litter decomposition, while the degree of humification in newly shed litters before decomposition remains unclear. In this study, we aimed to explore the degree of humification and conjugate structures of humic substances in newly shed litters, and their variations between litter types with different chemical components and between seasons with different environmental conditions. Materials and methods: In this study, we collected fresh foliar (evergreen vs. deciduous and tree vs. shrub), twig, flower, and fruit litters by litter traps in a subalpine forest on the eastern Tibetan Plateau monthly from April to November 2016. The humification degrees of these newly shed litters were evaluated by the optical properties (i.e., ΔlogK, E4/E6, and A600/C) of the alkaline-extracted humic acid-like solutions. E4/E6 and ΔlogK are often used to evaluate the degree of humification, and these values were also used to classify the maturity levels of humic substances. Results and discussion: We found that the ΔlogK, E4/E6, and A600/C values varied greatly among seasons with a higher degree of humification observed in August than in the other months for foliar litter. Compared with other litter components, foliar litter exhibited higher ΔlogK, E4/E6, and A600/C values, indicating that fresh foliar litter had a lower degree of humification than the other litters. Twig litter had more stable and abundant precursors of soil organic matter with a higher degree of humification. Moreover, higher degrees of humification with lower ΔlogK and E4/E6 values were observed in evergreen and tree litter species than in deciduous and shrub species, indicating that deciduous and shrub species retained strong abilities to sequester carbon (C). Conclusions: The degree of humification in newly shed litters was strongly affected by chemical components. Twig litter had more stable and abundant precursors of soil organic matter with high degree of humification. Deciduous species and shrub species retained strong abilities to sequester C in cold biomes. Additionally, the humic substances in newly shed litters were very young (type Rp), as assessed by the ΔlogK and A600/C values according to the Kumada’s classification, implying that these humic substances might have faster turnover times but strongly contribute to soil organic matter formation in this subalpine forest.

25791. 题目: Formation of assimilable organic carbon (AOC) during drinking water disinfection: A microbiological prospect of disinfection byproducts
文章编号: N19121416
期刊: Environment International
作者: Guocheng Huang, Tsz-Wai Ng, Huan Chen, Alex T. Chow, Shengwei Liu, Po Keung Wong
更新时间: 2019-12-14
摘要: Disinfection processes might alter the chemical structure of biological recalcitrant natural organic matter (NOM) in source water to form assimilable organic carbon (AOC), which can be readily utilized by microbes for growth. However, AOC has not been classified as disinfection byproducts (DBPs) before and little is known about the chemical and structural nature of AOC. This study, for the first time, considers the disinfection-induced AOC as DBPs from a microbiological perspective. The AOC formation by three types of disinfection processes, i.e., chlorination, UVC irradiation (254 nm) and photocatalysis represented by TiO₂-UVA in drinking water containing two reference NOM materials of Suwannee River and Nordic Reservoir (SRNOM and NRNOM, respectively) were comparatively benchmarked using Pseudomonas aeruginosa as inoculum. Results showed that chlorination caused a substantial increase in AOC content, whereas TiO₂-UVA led to a moderate increase in AOC content and UVC rendered the AOC content unchanged, independent of the types of NOM. Molecular weight indicated by spectral slope ratio and fluorescence fingerprint were found to not provide critical information about the AOC formation potential. FTIR and FT-ICR-MS results indicated that the AOC formation by chlorination was attributed to the oxidation and chlorine substitution on aromatic molecules to form molecules with carboxylic- and alcohol- functionalities, as well as chlorinated aromatics. These molecules could be metabolized and assimilated by Pseudomonas species by a catechol pathway. The results obtained in this study can provide valuable insight regarding the selection of proper technologies for disinfection to prevent microbial growth/regrowth in the distributing system and is intended to encourage more thinking and research on AOC as a new prospect of DBPs during disinfection of drinking water.
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25792. 题目: Biowaste-source-dependent synthetic pathways of redox functional groups within humic acids favoring pentachlorophenol dechlorination in composting process
文章编号: N19121415
期刊: Environment International
作者: Xinyu Zhao, Wenbing Tan, Jingjing Peng, Qiuling Dang, Hui Zhang, Beidou Xi
更新时间: 2019-12-14
摘要: Humic acids (HAs) can function as electron mediators for contaminants transformation in different environments. The humus respiration can facilitate pentachlorophenol (PCP) dechlorination during different biowastes composting. However, different characteristics of synthetic pathways of redox functional groups within HAs during different biowastes composting have never been characterized. Herein, we assessed the synthetic pathways of redox functional groups within HAs from protein-, lignocellulose-, and lignin-rich composts that facilitated the microbially reductive dechlorination of PCP, respectively. The results show that the aromatic systems are the major electron-accepting moieties of HAs and function as electron shuttles to facilitate the PCP dechlorination. Amino acid and reducing sugar are the major precursors for the synthesis of redox functional groups within HAs in protein-rich composts, and polyphenols and amino acids are discerned as the significant components to synthesize redox functional groups of HAs in lignocellulose- and lignin-rich composts. Seven groups of bacterial communities based on relationships among remarkable precursors, key bacterial communities, and redox functional groups within HAs are classified as participants in the precursors’ catabolism and aromatic system’ anabolism. Furthermore, the significant environmental factors on the synthetic pathways of redox functional groups within HAs in composting are confirmed by structural equation models. Conclusively, the regulating methods for promoting PCP dechlorination by HAs during different biowastes composting are proposed. Our results can help in understanding the distinct formative mechanisms of redox functional groups within HAs during different biowastes composting, providing insights into a classification-oriented approach for recycling utilization of different biowastes.

25793. 题目: Partitioning of iron and plutonium to exopolymeric substances and intracellular biopolymers: A comparison study between the coccolithophore Emiliania huxleyi and the diatom Skeletonema costatum
文章编号: N19121414
期刊: Marine Chemistry
作者: Peng Lin, Chen Xu, Wei Xing, Luni Sun, Kathleen A. Schwehr, Antonietta Quigg, Peter H. Santschi
更新时间: 2019-12-14
摘要: Iron (Fe), a micronutrient for algal growth, and plutonium (Pu), an anthropogenic radionuclide, share some common features. This includes similar oceanic distributions when different input modes are taken into account, as well as their chemical behavior, such as a high affinity to natural organic matter (NOM). The NOM produced by various phytoplankton communities can potentially influence Fe cycling in the ocean, and likely also influence the transport behavior of Pu. We conducted laboratory incubation experiments using the coccolithophore Emiliania huxleyi and the diatom Skeletonema costatum, in the presence of ⁵⁹Fe and ²³⁸Pu as radiotracers, in order to differentiate Fe and Pu uptake by extracellular exopolymeric substances (EPS) and intracellular biopolymers. The Fe and Pu distributions in select organic compound classes produced by these two types of phytoplankton, including proteins, total carbohydrates (TCHO) and uronic acids (URA), were compared. Our results indicated that most of the Fe and Pu (>95%) were found concentrated in E. huxleyi-derived non-attached EPS, while much less (<2%) was present in the intracellular fraction of E. huxleyi. In contrast, in the diatom S. costatum, Fe and Pu were both distributed with EPS > intracellular biopolymers > outer cell covering (i.e., frustule). In fact, over 50% of the Fe was concentrated in S. costatum-derived attached EPS and intracellular biopolymers. The diatom derived Fe-EPS complexes were more hydrophobic, with stronger tendency to aggregate in seawater. Fe binding to biopolymers in both E. huxleyi and S. costatum cultures was related to URA concentrations, but the overall distribution of URA between these two phytoplankton species was different (e.g., high intracellular abundance of URA in S. costatum but low intracellular URA abundance in E. huxleyi). Our findings suggest that the presence of URA on cellular surfaces of S. costatum (i.e., attached EPS) and its high intracellular fraction could be an indicator for Fe transport from the surrounding seawater to the diatom cells. However, for the coccolithophore E. huxleyi, Fe was not efficiently taken up during its growth. Instead, the more hydrophilic non-attached EPS (i.e., low protein/TCHO ratio) produced by E. huxleyi could have stabilized Fe in the colloidal form as Fe-EPS complexes. Similar partitioning behavior of Fe and Pu suggests that Pu isotopes can potentially serve as a tracer for Fe biogeochemistry in the ocean.

25794. 题目: Can biochar conserve water in Oregon agricultural soils?
文章编号: N19121413
期刊: Soil and Tillage Research
作者: Claire L. Phillips, Sarah E. Light, Hero T. Gollany, Stephanie Chiu, Thomas Wanzek, Kylie Meyer, Kristin M. Trippe
更新时间: 2019-12-14
摘要: Few studies have evaluated the ability of biochar to improve soil water content under field conditions. Our objective was to assess the potential drought benefits of biochar across a range of soil textures by measuring indicators of hydraulic capacity and water-retention curves for field-amended soils. Two biochars, conifer wood and wheat straw, were incorporated by rotary tillage at amendment rates of 9−36 Mg ha⁻¹ in four locations. All four soils showed a significant increase (p≤0.04) in saturated water content of 0.05–1.7 % volume per Mg ha⁻¹ biochar added, but no increase in water content at field capacity. There were significant (p<0.01) decreases in volumetric water content at wilting point by 0.09 to 0.8 % per Mg ha⁻¹ of biochar added in all soil textures. This translated to small, significant increases in plant-available water capacity of the same magnitude. Although the conifer wood biochar was less hydrophobic and had 14 % more internal pore space than the wheat straw biochar, both biochars had similar impacts on volumetric soil water content (θ). Simulations of soil drying and recharge using moisture retention curves and the Hydrus-1D model indicated that biochar amendment would generally decrease θ in the loam soil, and would have minimal impact on θ (± 1 %) in the more coarse textured soils. Monitoring of in situ θ in two of these soils showed similar results. Biochar sped up soil drying in the loam following irrigation, but had no impact on θ in the loamy sand. These results suggest limited utility for biochar as a drought adaptation tool in the first year following incorporation into these medium- to coarse-textured soils.

25795. 题目: Biochar-related studies from 1999 to 2018: a bibliometrics-based review
文章编号: N19121412
期刊: Environmental Science and Pollution Research
作者: Dongyang Li, Rui Zhao, Xing Peng, Zhifei Ma, Ying Zhao, Tiancheng Gong, Mengyang Sun, Yuxin Jiao, Tianxue Yang, Beidou Xi
更新时间: 2019-12-14
摘要: Biochar has been paid great attentions during the last two decades, because of its resources potentials and environmental benefits. A bibliometric analysis was applied to assess the publications regarding the keyword biochar from the Web of Science database during the period of 1999 to 2018. A total of 8629 publications were obtained with a rapid increase of annual citations and number of papers. The research topics were diversified, which were mainly divided into “Environmental Sciences and Ecology,” “Agriculture,” and “Engineering.” Bioresource Technology was the journal which published most of the relevant papers. China ranked first in the number of published papers, followed by the USA, Australia, UK, and Germany. Especially, China established close collaboration with the USA in joint publication. Analysis of the keywords indicated that biochar production, comparative sorption, soil-applied black carbon, and soil management were the main research hotspots of biochar. The burst detection reflected that the innovation of biochar production and the new application field of biochar was the future research trends. These results can provide insight into the research progress regarding biochar.

25796. 题目: Biochar efficacy for reducing heavy metals uptake by Cilantro (Coriandrum sativum) and spinach (Spinaccia oleracea) to minimize human health risk
文章编号: N19121411
期刊: Chemosphere
作者: Amir Zeb Khan, Xiaodong Ding, Sardar Khan, Tehreem Ayaz, Rivka Fidel, Muhammad Amjad Khan
更新时间: 2019-12-14
摘要: Environmentally friendly and cost-effective techniques are required to reclaim land degraded during mining activities. Bioaccumulation of heavy metals (HMs) in vegetables grown on contaminated soils can increase human health risks. The potential effects of hardwood biochar (HWB) was assessed for chromium (Cr), zinc (Zn), copper (Cu), manganese (Mn) and lead (Pb) bioavailability in mine-contaminated soils and their subsequently bioaccumulation in crops and associated health risk. HWB was applied to chromium-manganese mine contaminated soils at the rate of 3% to investigate the efficiency of HWB for the second crop in crop rotation technique. Cilantro (Coriandrum sativum) and spinach (Spinaccia oleracea) were grown as second crop in the same pots which were already used for rice cultivation as first crop (without adding further amendments). Application of HWB decreased the concentrations of Cr, Zn, Cu, Mn, and Pb in cilantro by 25.5%, 37.1%, 42.5%, 34.3%, and 36.2%, respectively as compared to control. In spinach, the reduction in concentrations of Cr was 75.0%, Zn 24.1%, Cu 70.1%, Mn 78.0%, and Pb 50.5% as compared to control. HWB significantly (P 0.01) reduced the HMs uptake in spinach cultivated in the amended soils as compared to the spinach in control. Bioaccumulation factor results also indicate that HWB decreased the bioaccumulation of selected HMs in cilantro and spinach, thus reducing health risks. Results of the study clearly demonstrate that the use of HWB can significantly reduce HMs in vegetables, associated health risk and improve food quality, therefore can be used as soil amendment for reclamation of mine-degraded soils.

25797. 题目: Bioconversion of Hg⁰ into HA-Hg for simultaneous removal of Hg⁰ and NO in a denitrifying membrane biofilm reactor
文章编号: N19121410
期刊: Chemosphere
作者: Z.S. Huang, Z.S. Wei, X.L. Xiao, B.L. Li, S. Ming, X.L. Cheng, H.Y. Jiao
更新时间: 2019-12-14
摘要: Bacterial mercury oxidation coupled to denitrification offers great potential for simultaneous removal of elemental mercury (Hg⁰) and nitric oxide (NO) in a denitrifying membrane biofilm reactor (MBfR). Four potentially contributory mechanisms tested separately, namely, membrane gas separation, medium absorption, biosorption and biotransformation, which contributed 4.9%/7.2%, 8.1%/8.9%, 38.8%/9.5% and 48.2%/84.9% of overall Hg⁰/NO removal in MBfR. Herein, Hg⁰ bio-oxidation, oxidative Hg⁰ biosorption and denitrification played leading roles in simultaneous removal of Hg⁰ and NO. Living microbes performed simultaneous Hg⁰ bio-oxidation and denitrification, in which Hg⁰ as electron donor was biologically oxidized to oxidized mercury (Hg²⁺), while NO as the terminal electron acceptor was denitrified to N₂. The Hg²⁺ further complexed with humic acids in extracellular polymeric substances via functional groups (-SH, –OH, -NH^- and -COO^-) and formed humic acids bound mercury (HA-Hg). Non-living microbial matrix performed oxidative Hg⁰ biosorption, in which Hg⁰ may be physically adsorbed by cellular matrix, then non-metabolically oxidized to Hg²⁺ via oxidative complexation with –SH in humic acids and finally cleavage of S–H bond and surface charge transfer led to formation of HA-Hg. Therefore, bioconversion of Hg⁰ to HA-Hg by Hg⁰ bio-oxidation and oxidative Hg⁰ biosorption coupled with NO denitrification to N₂ dynamically cooperated to accomplish simultaneous removal of Hg⁰ and NO in MBfR.
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25798. 题目: Aromatic hydrocarbons provide new insight into carbonate concretion formation and the impact of eogenesis on organic matter
文章编号: N19121409
期刊: Organic Geochemistry
作者: C. Plet, K. Grice, A.G. Scarlett, W. Ruebsam, A.I. Holman, L. Schwark
更新时间: 2019-12-14
摘要: Investigation of aromatic biomarkers extracted from carbonate concretions can contribute to characterize the enhanced microbial activity that mediates carbonate concretion formation. This microbial footprint can be further inferred from the stable isotopic values of carbonate (δ¹³C) and pyrite (δ³⁴S). Here, we used a combination of GC-MS and GC×GC-ToF-MS to compare the aromatic fractions of two Toarcian carbonate concretions from the H. falciferum ammonite zone of the Posidonia Shale (SW-Germany) and their host sediment. The results revealed that n-alkylated and phytanyl arenes were enhanced in the concretions relative to the host sediment. These findings support a very early diagenetic (eogenetic) microbial source for alkylated and phytanyl arenes derived from the microbial ecosystem mediating concretion formation. In contrast, aromatic compounds formed by thermal maturation (e.g. polycyclic aromatic hydrocarbons, aromatic steroids, organic sulphur compounds) remained invariant in host rock and concretion samples. When combined with bulk sediment and concretion properties, the distribution of aromatic compounds indicates that eogenetic microbial activity upon concretion growth does not diminish organic matter quality.

25799. 题目: On the negative carbon isotope excursion across the Wuchiapingian–Changhsingian transition: A regional event in the lower Yangtze region, South China?
文章编号: N19121408
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Lijia Li, Zhiwei Liao, Lidan Lei, Gary G. Lash, Anqing Chen, Xianfeng Tan
更新时间: 2019-12-14
摘要: Previous studies have reported faunal changeover and carbon isotope excursions through the Wuchiapingian–Changhsingian (WC) transition, a geologically significant period of time that bridged two major extinction events: the end-Permian and Guadalupian–Lopingian boundary mass extinctions. However, the causes of the carbon isotope excursion across the WC interval remain poorly understood. This study presents sedimentological and geochemical data from three well-exposed sections in the lower Yangtze region, South China. A strong negative carbon isotope excursion in organic matter is recorded across the WC interval and correlates well with other sections in South China. Sedimentology and elemental geochemistry indicate that the lower Yangtze region experienced a distinct regional deepening during the WC transition inducing bottom water redox changes increased primary productivity. Possible causes of the negative carbon isotope excursion at the WC boundary include selective preservation of organic matter during early diagenesis under anoxic/euxinic conditions and changes in terrigenous organic matter input. Both of these factors were controlled by regional relative sea-level rise triggered by contemporaneous tectonic movements.

25800. 题目: Biochar-induced migration of tetracycline and the alteration of microbial community in agricultural soils
文章编号: N19121407
期刊: Science of The Total Environment
作者: Hua-Yu Liu, Chao Song, Shan Zhao, Shu-Guang Wang
更新时间: 2019-12-14
摘要: Recently, biochar is widely used as a soil amendment to improve soil properties, which might affect the fate and behavior of contaminants in soil. In this study, we investigated the effect of biochar on the migration of tetracycline (TC) in soil and their combined impacts on microbiome. Due to the strong interaction between soil and TC, adsorption, rather than photolysis or biodegradation, was the dominating dissipation way of TC in soil. Moreover, biochar could promote the vertical migration of TC through the decreased soil bulk density and its lower adsorption capacity. After 90-day incubation, only slight impact of TC on soil bacterial community was observed due to the rapid dissipation of TC in soil, whereas more available C supply induced by biochar significantly altered bacterial community via the enhancement of copiotrophic bacteria. Besides, biochar could decrease the soil pH and thus change the composition of fungal community. The effect of TC on fungal community was partially counteracted by biochar, which could adsorb part of TC and thus decrease the contact of TC with microorganisms. This work will improve our understanding of the fate of organic pollutants and evolution of microbiome in soil where biochar servers as soil amendment.
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