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17641. 题目: The Dual Mechanisms of Composite Biochar and Biofilm towards Sustainable Nutrient Release Control of Phosphate Fertilizer: Effect on Phosphorus Utilization and Crop Growth
文章编号: N21050309
期刊: Journal of Cleaner Production
作者: Tong An, Hao Cheng, Yan Qin, Weihua Su, Haishan Deng, Jianning Wu, Zhiyong Liu, Xuhong Guo
更新时间: 2021-05-03
摘要: The low utilization rate of phosphorus fertilizers is a common concern and is caused by high leaching loss rates and rapid nutrient release. While the precipitation with soil components also brings a series of problems. To address these problems, we propose a composite biochar and a hydrophobic biofilm to act as a synergistic mechanism for nutrient release control and to provide the required nutrients for crop growth. We optimized the preparation of composite biochar materials (1:1.2, 1.5 h, 450 °C) and explored the nutrient loading mechanism by different adsorption kinetic model fitting. The fitting curve showed that PO43- best fit with the Redlich-Peterson model with a high correlation coefficient (R2 = 0.9923). The water contact angle of a cotton stalk hydrophobic membrane material was 109°. Leaching experiments showed phosphate leaching losses increased with an increase in the amount in hydrophobic biofilm (2%, 4%, 6%), which showed a decreasing trend of 24%, 16% and 10%, respectively. After 31 d of nutrient release, the cumulative release rate of HCP2 was 65%, which matched the growth demand of corn maize crops and had a significant effect on early maize growth. All agronomic data showed optimized root length (32.5 cm), plant height (58.7 cm), dry weight (0.527 g) and fresh weight (4.907 g). This showed that the phosphate fertilizer carrier and co-release system constructed by the combination of biochar and biofilm has great advantages in promoting crop growth and a sustainable agricultural economy.

17642. 题目: Potential use of silica-rich biochar for the formulation of adaptively controlled release fertilizers: A mini review
文章编号: N21050308
期刊: Journal of Cleaner Production
作者: Minh N Nguyen
更新时间: 2021-05-03
摘要: The application of biochar is a win-win practice to improve soil properties, reduce the mobility of agrochemicals and respond to climate change. However, there is likely a lack of momentum in many agricultural countries where governments cannot involve farmers in this practice. This suggests that we need more incentives to integrate biochar into other field practices. This paper schematizes biochars, in particular those rich in silica, as potential composites for formulating adaptively controlled-release fertilizers to encourage the utilization of agricultural residues in smart fertilizer technology. Recent findings on the microstructure and physicochemical properties of silica-rich biochars indicated that biochars can potentially be used as controlled release platforms. The biochar builds up a skeleton and creates space for loading fertilizers; in addition, silica with tuneable dissolution can act as windows for releasing fertilizers. This review paper demonstrates a new route for the formulation of adaptively controlled release fertilizers and provides additional insight into cascading use and upcycling billions of tons of agricultural silica-rich biomass worldwide.

17643. 题目: Biochar effects acidic soil remediation and Brassica oleracea L. toxicity—A case study in subtropical area of China
文章编号: N21050307
期刊: Environmental Technology & Innovation
作者: Muhammad Ibrahim, Gang Li, Yu-Ting Tang
更新时间: 2021-05-03
摘要: As an important part of the terrestrial ecosystem, agriculture ecosystem plays a key role in supporting and maintaining human survival on earth. To restore contaminated sites as well as improve soil fertility, applying biochar to soil is an environmentally approachable technology. To evaluate the benefit of applying peanut shells biochar (PNB) to the soil, a glasshouse experiment was conducted at a ratio of biochar of 2%, 4%, and 6% of either type of biochar. The results indicated that PNB application increased soil pH, electric conductivity (EC), total carbon (TC), total nitrogen (TN), and dissolved organic carbon (DOC) in soil. The bioavailable concentration of PTEs such as cadmium (Cd), nickel (Ni), arsenic (As), chromium (Cr) and lead (Pb) significantly (P ≤ 0.05) decreased by about 25%, 50%, 31%, 55%, and 41% by applying PNB at ratio of 6%. Furthermore, in the same treatment group (PNB-6%), the significant (P < 0.01) decrease in Cr (62%), Ni (44%), As (43%), Cd (41%), and Pb (44%) bioaccumulation was detected in Brassica oleracea L. shoots.. In the treatment group of RSB-6%, B. oleracea antioxidant enzymes such as superoxide dismutase (SOD), guaiacol peroxidase (POD), and catalase (CAT) declined significantly (P ≤ 0.05) by about 68%, 55%, and 38% respectively. A statistically highest significant (P ≤ 0.05) increase in concentration of chlorophyll a, b (125%, 350%) and carotenoid (166%) was found in the B. oleracea shoots treated with the highest ratio of PNB (6%). Leaf soluble protein significantly (P<0.01) raised by about 50%, 100%, and 250% in the B. oleracea grew in the soil treated with PNB at the ratio of 2%, 4%, and 6%, respectively, while leaf soluble proline and sugar concentrations significantly (P ≤ 0.05) declined by about 40%, 60%, and 80% as well as 30%, 50%, and 70%. The results suggested that PNB-6% was the best acidic soil amendment among the tested treatment. However, larger-scale studies are needed to verify the effects of PNB on plant growth, toxicity, and soil properties in diverse environmental conditions before widespread agricultural application.

17644. 题目: Recovering Cr(III) from chromium-containing waste: an in-depth study on mechanism via retaining organic matters
文章编号: N21050306
期刊: Journal of Environmental Chemical Engineering
作者: E Tao, Ying Cheng, Shuyi Yang, Hongtao Zou
更新时间: 2021-05-03
摘要: Recovering Cr(III) from chromium-containing waste (CCW) is considered to be a friendly way to protect environment. In this paper, the recovery of Cr(III) from CCW is achieved, via alkali incineration (NaOH and Na2CO3), followed with leaching process using HCl. Firstly, it is demonstrated that there is a large amount of organic matters (oxygen-containing functional groups contained in collagen) in CCW, charactering with Infrared spectrophotometry (FT-IR), Thermogravimetric aanalysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, density functional theory (DFT) simulation method is carried out to study the inhibitory behavior of organic matters on recovery of Cr(III). Through geometric optimization, binding energy calculation and a series of electronic structure analysis, the influence of organic matters are analyzed in detail. According to the calculation results, it is clarified that the inhibition mechanism of organic matters on Cr(III) is mainly contributing by forming covalent bond and -OH exhibits greater inhibiting effect than -COOH. In this examine, the related factors are also investigated to reduce the amount of organic matters that is destroyed, including extractant species, alkali dosage, acid dosage and acid concentrations. Finally, the recovering efficiency of Cr(III) is greatly enhanced (95.83%), associated with optimized factors in the process.

17645. 题目: (Im)mobilization of arsenic, chromium, and nickel in soils via biochar: A meta-analysis
文章编号: N21050305
期刊: Environmental Pollution
作者: Zahra Arabi, Jörg Rinklebe, Ali El-Naggar, Deyi Hou, Ajit K. Sarmah, Eduardo Moreno Jiménez
更新时间: 2021-05-03
摘要: Biochar is a promising immobilizing agent of trace elements (TEs) in contaminated soils. However, several contradictory results have been reported regarding the potential of biochar to immobilize arsenic (As), chromium (Cr), and nickel (Ni) in contaminated soils. We conducted a meta-analysis on the published papers since 2006 until 2019 to examine the effects of biochar on the chemical (im)mobilization of As, Cr, and Ni in contaminated soils and to elucidate the major factors that control their interactions with biochar in soil. We synthesized 48 individual papers comprised of a total of 9351 pairwise comparisons and used the statistical tool of Cohen's d as an appropriate effect size for the comparison between means. We found that the application of biochar often increased the As mobilization in soils. Important variables that modulated the biochar effects on As mobilization in soil were pyrolysis temperature and time (ranging between 8-16 times when T>450°C and t>1hr), organic matter (7-16 times when SOM<3%) and further site conditions. In contrast to As, biochar efficiently immobilized Cr and Ni in contaminated soils. The extent of the Cr and Ni immobilization was determined by the feedstock (Cr: 7-18 times for agricultural residue-derived biochar; Ni: 13-32 times for woody biomass-derived biochar). Our meta-analysis provides a compilation on the potential of different types of biochar to reduce/increase the mobilization of As, Cr, and Ni in various soils and under different experimental conditions. This study provides important insights on factors that affect biochar’s efficiency for the (im)mobilization of As, Cr, and Ni in contaminated soils. While biochar effectively immobilizes Cr and Ni, a proper management of As-polluted soils with pristine biochar is still challenging. This limitation might be overcome by modification of biochar surfaces to exhibit higher surface area and functionality and active sites for surface complexation with TEs.

17646. 题目: Microalgae-based technology for antibiotics removal: From mechanisms to application of innovational hybrid systems
文章编号: N21050304
期刊: Environment International
作者: Qian Xiong, Li-Xin Hu, You-Sheng Liu, Jian-Liang Zhao, Liang-Ying He, Guang-Guo Ying
更新时间: 2021-05-03
摘要: Antibiotics contamination is an emerging environmental concern, owing to its potential risks to ecosystems and human health. Microalgae-based technology has been widely reported as a promising alternative to conventional wastewater treatment, since it is a solar-power driven, ecologically friendly, cost-effective, and sustainable reclamation strategy. This review provides fundamental insights into the major mechanisms underpinning microalgae-based antibiotics removal, including bioadsorption, bioaccumulation, and biodegradation. The critical role of extracellular polymeric substances on bioadsorption and extracellular biodegradation of antibiotics are also covered. Moreover, this review sheds light on the important factors affecting the removal of antibiotics by microalgae, and summarizes several novel approaches to improve the removal efficiency, including acclimation, co-metabolism and microbial consortium. Besides, hybrid systems (such as, microalgae-based technologies combined with the conventional activated sludge, advanced oxidation processes, constructed wetlands, and microbial fuel cells), and genetic engineering are also recommended, which will be feasible for enhanced removal of antibiotics. Finally, this review also highlights the need for further studies aimed at optimizing microalgae-based technology, with emphasis on improving performance and expanding its application in large-scale settings, especially in terms of technical, environmental-friendly and economically competitiveness. Overall, this review summarizes current understanding on microalgae-based technologies for removal of antibiotics and outlines future research directions.

17647. 题目: New use for biochar derived from bovine manure for tetracycline removal
文章编号: N21050303
期刊: Journal of Environmental Chemical Engineering
作者: Jiawei Zhao, Feng Gao, Yue Sun, Wanyi Fang, Xiaohan Li, Yingjie Dai
更新时间: 2021-05-03
摘要: This study investigated the physicochemical properties of bovine manure biochar (BC) obtained at different temperature of 500 °C (BC-500) and 700 °C (BC-700). The effects of the contact time, temperature, pH, background electrolyte, and regenerated adsorbent on the adsorption of tetracycline (TC) by BC-500 and BC-700 were determined. The TC removal rates were 95.31% by BC-500 after 12h and 99.70% by BC-700 after 4h. The maximum adsorption capacities of BC-500 and BC-700 were 5.38mg/g and 5.82mg/g, respectively. The adsorption of TC by BC-500 and BC-700 was characterized better by pseudo-second order kinetics. The adsorption kinetics of BC-500 and BC-700 were fitted well by the pseudo-second order kinetic model. Regeneration experiments showed that BC-500 and BC-700 still delivered satisfactory removal efficiencies even after three cycles, 52.95% and 77.20%, respectively. The main mechanisms responsible for the adsorption of TC by BC were determined as hydrophobic interactions and π-π electron donor acceptor interactions. This new type of inexpensive and readily available adsorbent may provide an effective solution for the removal of TC from wastewater in the future.

17648. 题目: Biochars ages differently depending on the feedstock used for their production: Willow- versus sewage sludge-derived biochars
文章编号: N21050302
期刊: Science of The Total Environment
作者: Anna Siatecka, Krzysztof Różyło, Yong Sik Ok, Patryk Oleszczuk
更新时间: 2021-05-03
摘要: The aim of this study was to determine the effect of abiotic aging of biochars under controlled laboratory conditions on its physicochemical properties and in consequence on their stability. Biochars (BCs) produced at 500 and 700 °C from willow or sewage sludge were incubated at different temperatures (−20, 4, 20, 60, or 90 °C) for 6 and 12 months. Pristine (i.e. immediately after their production) and aged BCs were characterized using a range of complementary methods. As a result of simulated temperature aging, there was a change in all biochar properties studied, with the direction of these changes being determined by both the type of feedstock and biochar production temperature. At all temperatures, aging was the most intense during the first 6 months and led to oxidation of the biochars and removal of the most labile components from them. The intensity of these processes increased with increasing aging temperature. Incubation of the biochars for another 6 months did not have such a significant effect on the biochar properties as that observed during the first months of incubation, which is evidence that the biochars had reached stability. The sewage sludge-derived biochars with a higher mineral content than the willow-derived biochars were less stable. The low-temperature biochars (BC-500) with lower aromaticity were more prone to abiotic oxidation than the high-temperature biochars (BC-700) with higher aromaticity and structurally ordered C. Based on this study, it can be concluded that aging induced changes will be specific for each biochar, i.e. they will depend on both the type of feedstock and pyrolysis temperature. Nonetheless, all biochars will be oxidized to a smaller or greater extent, which will result in an increase in the number of surface oxygen functional groups, an increased degree of their hydrophilicity and polarity, and a decrease in pH.

17649. 题目: Litter crusts enhance soil nutrients through bacteria rather than fungi in sandy ecosystems
文章编号: N21050301
期刊: CATENA
作者: Yu Liu, Caroline A. Havrilla, Chao Jia, Xiao-Zhen Liu, Gao-Lin Wu
更新时间: 2021-05-03
摘要: Litter crusts in dryland ecosystems can promote ecosystem functioning through modification of the soil microhabitat. Yet, we still have a limited understanding of how soil microbial communities associated with litter crusts may contribute to soil functioning. Therefore, we examined the changes of soil organic carbon, soil total nitrogen, soil ammonium nitrogen and nitrate nitrogen and microbial communities (i.e., bacteria & fungi) associated with litter crusts, bare soil and biocrusts, to interpret potential relationships between litter crusts their associated microbial communities and soil nutrient functioning in a sandy ecosystem, China. We found that increases in soil organic carbon and total nitrogen associated with litter crusts was closely related to the bacterial community but not to the fungal community. Positive effects of litter crusts on soil nutrient inputs were associated with soil moisture and porosity potentially regulated by bacterial communities. Our results provide insights into ecological functioning of microbial communities associated with litter crusts and suggest that litter crusts enhance soil nutrient availability primarily through bacteria rather than fungi. This finding highlights the potential ecological functioning of litter crusts in governing soil nutrient dynamics.

17650. 题目: Photosensitized formation of sulfate and volatile sulfur gases from dissolved organic sulfur: Roles of pH, dissolved oxygen, and salinity
文章编号: N21050118
期刊: Science of The Total Environment
作者: Jian-Long Li, Xing Zhai, Lin Du
更新时间: 2021-05-01
摘要: The photodegradation of dissolved organic sulfur (DOS) is a potential source of aqueous sulfate and its chemical precursors in surface water. However, the photochemical fate of DOS and factors that control its fate still remain unclear. Herein, we employed a DOS model featuring a photosensitizer (humic acids, HA) to investigate the photochemical degradation pathways of DOS in various natural water sources, from which we observed the substantial photosensitized formation of sulfate, methanesulfonic acid (MSA), carbonyl sulfide (COS), and carbon disulfide (CS2). However, the photochemical production of sulfate and MSA tends to be more efficient than COS and CS2. The formation of sulfur-containing photodegradation products was also strongly affected by the identity of the organic sulfur precursor, the oxygen concentration, and the pH, while the salinity did not significantly influence the production ratios. Our results revealed that the photosensitization of DOS contributed significantly to the overall production of sulfate and MSA production, especially in acidic and oxygen-enriched environments, which was attributed to the photochemical production of reactive intermediates, such as excited CDOM (3CDOM*) and reactive oxygen species (ROS). Considering the coexistence of DOS and photosensitizers in aquatic environments, photochemistry may play an essential role in the fate of aquatic DOS.

17651. 题目: Microplastics as an emerging threat to plant and soil health in agroecosystems
文章编号: N21050117
期刊: Science of The Total Environment
作者: Jie Zhou, Yuan Wen, Miles R. Marshall, Jie Zhao, Heng Gui, Yadong Yang, Zhaohai Zeng, Davey L. Jones, Huadong Zang
更新时间: 2021-05-01
摘要: Microplastics (MPs, <5 mm in diameter) have been widely recognized as a critical environmental issue due to their extensive use and low degradation rate. Based on current evidence, our aim is to evaluate whether MPs represent an emerging threat to plant-soil health in agroecosystems. We assess the ecological risks to plant-microbe-soil interactions associated with MPs and discuss the consequences of MPs on soil carbon (C), nutrient cycling, as well as greenhouse gas emissions in agroecosystems. We also identify knowledge gaps and give suggestions for future research. We conclude that MPs can alter a range of key soil biogeochemical processes by changing its properties, forming specific microbial hotspots, resulting in multiple effects on microbial activities and functions. Mixed effects of MPs on plant growth and performance can be explained by the direct toxicity of MPs or the indirect alteration in soil physical structures and microbial communities (i.e. symbiotic arbuscular mycorrhizal fungi). Because of the diverse nature of MPs found in soils, in terms of polymer type, shape and size, we also see differing effects on soil organic matter (SOM) decomposition, nutrient cycling, and greenhouse gases production. Importantly, increased bioavailable C from the decomposition of biodegradable MPs, which enhances microbial and enzymatic activities, potentially accelerates SOM mineralization and increases nutrient competition between plant and microbes. Thus, biodegradable MPs appear to pose a greater risk to plant growth compared to petroleum-based MPs. Although MPs may confer some benefits in agroecosystems (e.g. enhanced soil structure, aeration), it is thought that these will be far outweighed by the potential disbenefits.

17652. 题目: The possible role of the Surface Active Substances (SAS) in the airborne transmission of SARS-CoV-2
文章编号: N21050116
期刊: Environmental Research
作者: Irena Ciglenečki, Palma Orlović-Leko, Kristijan Vidović, Viša Tasić
更新时间: 2021-05-01
摘要: Surface active substances (SAS) have a potential to form films at different interfaces, consequently influencing the interfacial properties of atmospheric particulate matter (PM). They can be derived from both human activities and natural processes, and can be found in an indoor and outdoor environment. This paper's fundamental question is possible role of the SAS in stabilizing respiratory aerosols in the closed space. In that context, we discuss results of preliminary measurements of the SAS and dissolved organic carbon (DOC) concentrations in the water-soluble fractions of PM2.5 and PM10 that were sampled simultaneous in primary school inside and outside of the building. The concentrations of SAS were determined using highly sensitive electrochemical measurements. It was observed that SAS and DOC concentrations have been enhanced indoor in both PM fractions. Consistent with these results, a discussion arises on the possibility that SAS could play a crucial role in respiratory droplet dispersion as stabilizers, especially in a closed space. At the same time, we assume that they could prolong lifetime of respiratory aerosols and as well viability of some (possible SARS-CoV-2) virus inside of the droplets.

17653. 题目: Analysis of Physicochemical Factors Regulating Transport Behaviors of Sulfonamide Antibiotics in Saturated Porous Media
文章编号: N21050115
期刊: Journal of Hydrology
作者: Peiyao Dong, Wenhui Qiu, Xin He, Yong Zhang, Chunmiao Zheng
更新时间: 2021-05-01
摘要: Sulfonamide antibiotics (SAs) are commonly used antibiotic classes in livestock worldwide. SAs are discharged to the environment and then may accumulate in rivers and aquifers, thereby diminishing water quality and the overall health of the ecosystem. While the occurrence and distribution of SAs in water environments have been the subject of numerous investigations, the fate and transport of SAs in aquifers have been less understood. In the present work, four of the most used SAs, including sulfadiazine (SDZ), sulfathiazole (STZ), sulfamethazine (SM2), and sulfamethoxazole (SMX), were selected for laboratory experiments and modeling analysis. The experiments were conducted in saturated columns filled with two common porous media, quartz sands and limestone grains. Results showed that the SAs had mobility changing on the order (from high to low) of SMX > SM2 > SDZ > STZ in the column, with SMX being the least absorbed SA by quartz sand or limestone grains. Moreover, calcium ionsinhibited the transport of SAs more strongly than that of sodium ions, while the inhibitory effect was slightly enhanced with an increasing Na + concentration from 0 to 10 mM. In contrast, the presence of humic acid facilitated the transport of SAs. Although the four SAs have similar molecular structures, their adsorption and transport characteristics were shown to be quite different. The dynamics of the adsorption and transport of SAs in groundwater can be effectively described by a two-site adsorption model coupled with advection and dispersion. This study sheds new light on the transport of SAs, contributing to a better understanding of how to control the presence and migration of antibiotics as new emerging contaminants in groundwater.

17654. 题目: Denitrification performance, biofilm formation and microbial diversity during startup of slow sand filter using powdery polycaprolactone as solid carbon source
文章编号: N21050114
期刊: Journal of Environmental Chemical Engineering
作者: Lei Yang, Lin-Kai Guo, Yong-Xiang Ren, Jiang-Wei Dou, Peng-Tao Zhu, Shen Cui, Zhi-Hao Zhang, Xiao-Tong Li
更新时间: 2021-05-01
摘要: To solve the problem of unsatisfactory nitrogen removal effect and long start-up in slow sand filter (SSF), the powdery polycaprolactone (PCL) with different particle sizes (40 and 200 mesh) were added to the lab-scale SSFs. This study compared the two solid carbon sources release capacity and enhanced denitrification performance in each SSF, and revealed the inner mechanism by analyzing the physical and chemical characteristics of the biofilm. The results represented that PCL200 could release organic carbon up to 273.9mg/L, which was much higher than PCL40 (121.2mg/L). Since the higher organic carbon release and specific surface area, the PCL200 was conducive to the rapid start-up of the SSF and achieving a desired removal efficiency of NO3--N (> 95%) and TN (> 80%) at the early stage of operation. In addition, large amounts of biomass and extracellular polymeric substances (EPS) were detected in the PCL200 system. Spectroscopic characterization further revealed EPS from two SSFs expressed similar fluorescence peak locations but different intensities. Specifically, the aromatic and tryptophan protein-like substances were the main fractions in EPS, and more functional bonds (C-(C, H), C=O, O-C-O) conducive to microbial flocculation were observed when adding PCL200. Furthermore, the high-throughput sequencing analysis showed the denitrifying bacteria almost accounted for 62.12% in the reactor with PCL200, and microorganisms in two SSFs were significant difference in amino acid and carbohydrate transportation and metabolism. Findings from this study would be valuable for enhancement of the denitrification and stability of SSF treating nitrogen-contaminated water bodies.

17655. 题目: Biogeochemical causes of sixty-year trends and seasonal variations of river water properties in a large European basin
文章编号: N21050113
期刊: Biogeochemistry
作者: Jiří Kopáček, Josef Hejzlar, Petr Porcal, Petr Znachor
更新时间: 2021-05-01
摘要: We evaluated long-term trends and seasonal variations in the major physical–chemical properties of the circum-neutral Slapy reservoir (Vltava, Czech Republic) from 1960 to 2019. Mean annual water temperature increased by 2.1 °C, flow maxima shifted by ~ 13 days from the early April to mid-March, and the onset of thermal stratification of water column and spring algal peaks advanced by 19 and 21 days, respectively, due to climate warming. Concentrations of major ions, phosphorus (P), and chlorophyll increased from the 1960s to the 1990–2000s, then decreased due to changing agricultural practices and legislation, intensified wastewater treatment, and decreasing atmospheric pollution. Concentrations of dissolved organic carbon (DOC) decreased from 1960 to the 1990s due to improved wastewater treatment, then began to increase in response to climate change and reduced acidic deposition. Concentrations of water constituents exhibited varying individual long-term and seasonal patterns due to the differing effects of following major processes on their production/removal in the catchment-river system: (1) applications of synthetic fertilizers, liming and farmland draining (NO3−, SO42−, Cl−, Ca2+, Mg2+, K+, and HCO3−), (2) wastewater production and treatment (DOC, P, N forms), (3) road de-icing (Cl− and Na+), (4) atmospheric pollution (SO42−), (5) climate change (DOC), and (6) the aging of reservoirs (NH4+). The water pH increased until the early 1990s, then decreased and exhibited pronounced seasonal variations, integrating the effects of changing external acidity sources and in-lake H+ sources and sinks (i.e., microbial CO2 production/consumption and availability and transformations of inorganic N), and changes in water buffering capacity. Anthropogenic and climatic effects, reservoir aging, and changes in water eutrophication thus may significantly affect water pH also in circum-neutral systems.

17656. 题目: Long-term environmental changes in the Geum Estuary (South Korea): Implications of river impoundments
文章编号: N21050112
期刊: Marine Pollution Bulletin
作者: Sujin Kang, Jung-Hyun Kim, Young Jin Joe, Kwangchul Jang, Seung-Il Nam, Kyung-Hoon Shin
更新时间: 2021-05-01
摘要: We investigated a sediment core collected from the Geum Estuary through sedimentological and geochemical analyses. Three lithological units were classified based on sedimentological characteristics. Unit 1 and Unit 3 were geochemically distinct, while Unit 2 was the transitional phase between them. The geochemical results suggest that the contribution of terrestrial organic carbon (OC) to the sedimentary OC pool in the coarse-grained Unit 1 was lesser than that of fine-grained Unit 3. The excess activity (210Pbex) and the sedimentation rate indicate that Unit 1 corresponded to 1977 Common Era (CE). Since the first dam construction on the Geum River began in 1975 CE, the deposition of Unit 1 in the Geum Estuary is likely associated with river impoundments, which reduce the delivery of fine-grained sediment and terrestrial OC to the estuary. This study highlights the role of river impoundments in altering the sedimentary OC and thus the sedimentary environment in the estuary.

17657. 题目: Chemical degradation of thermally altered silicified organic matter during acid maceration: a case study from the Lower Devonian Rhynie chert
文章编号: N21050111
期刊: Organic Geochemistry
作者: Frédéric Delarue, Thanh Thuy Nguyen Tu, Rémi Duhamel, Céline Paris, François Baudin
更新时间: 2021-05-01
摘要: The effect of standard acid maceration on organic matter (OM) from ancient silicified sediments remains undocumented. Early silicification favours preservation of organic moieties against thermal alteration over time. In this study, we investigated the effects of acid maceration on the structure of OM isolated from the Lower Devonian Rhynie chert. The structure of OM was investigated by combining Rock-Eval pyrolysis and Raman spectroscopy. Besides a loss of thermolabile organic matter owing to solvent extraction, Rock-Eval pyrolysis showed that standard acid maceration also causes a loss of C-H emissions at high pyrolysis temperature (> 500 °C). The standard acid maceration procedure was also associated with the disappearance of the D4 and D5 Raman spectrum shoulders assigned to C–H bonds in aliphatics and bitumens, respectively, entrapped in the macromolecular network. Taken together, Rock-Eval pyrolysis and Raman spectroscopy indicate that standard acid maceration can lead to the chemical degradation of syngenetic hydrocarbonaceous moieties of OM isolated from ancient silicified and thermally altered sediments. In sediments having experienced early silicification, which hampers bitumen migration and favours pyrobitumen formation, we suggest that novel in situ molecular analytical techniques are required to provide a thorough examination of the syngenetic molecular content independent of the soluble/insoluble operational definition.

17658. 题目: Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate
文章编号: N21050110
期刊: Waste Management & Research: The Journal for a Sustainable Circular Economy
作者: Zaber Ahmed, Mohd Suffian Yusoff, Nurul Hana Mokhtar Kamal, Hamidi Abdul Aziz
更新时间: 2021-05-01
摘要: The removal of concentrated colour (around 5039 Pt–Co) and chemical oxygen demand (COD; around 4142 mg L −1 ) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L −1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient ( R 2 = 0.98 and 0.96) and predicted R 2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.

17659. 题目: Multiple Factors Influence the Accumulation of Heavy Metals (Cu, Pb, Ni, Zn) in Forest Soils in the Vicinity of Roadways
文章编号: N21050109
期刊: Water, Air, & Soil Pollution
作者: Dawid Kupka, Mateusz Kania, Marcin Pietrzykowski, Adam Łukasik, Piotr Gruba
更新时间: 2021-05-01
摘要: Intensified vehicular traffic causes increased heavy metal contamination of the environment. We investigated the heavy metal chemistry of soils located under silver fir stands in the vicinity of Poland’s S7 roadway. Three sampling sites were located in fir stands in central Poland. Fieldwork included soil sampling of the organic (O) horizon and mineral (A) topsoil. We analyzed the soil pH, carbon (C) and nitrogen (N) concentration, and the HCl-extractable forms of sodium (Na) and heavy metals: copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). The stoichiometric ratios Cu:C, Ni:C, Pb:C, and Zn:C were also calculated. In all sites, a higher Na concentration was found in the 0–10 m from the forest edge. This zone was characterized by increased pH in the O horizon, increased Zn and Ni in the A horizon, and a decreased Pb in the O horizon. There was no clear pattern for the Cu concentration. The Ni:C and Zn:C ratios were correlated with pH, while Pb:C and Cu:C ratios were correlated with the clay minerals. HCl-extractable Ni and Zn concentrations in A horizon were greater near the roadway, revealing strong pH dependency. The roadway affects the geochemical background of the topsoil in the nearby fir stands. Mechanistically, we suggest that Na increases the soil pH and therefore enhances the ability of soil organic matter to bind Ni and Zn by releasing hydrogen from soil organic matter functional groups into the soil solution. A depleted Pb near the road was likely owing to the strong competition from Na.

17660. 题目: Different climate sensitivity of particulate and mineral-associated soil organic matter
文章编号: N21050108
期刊: Nature Geoscience
作者: Emanuele Lugato, Jocelyn M. Lavallee, Michelle L. Haddix, Panos Panagos, M. Francesca Cotrufo
更新时间: 2021-05-01
摘要: Soil carbon sequestration is seen as an effective means to draw down atmospheric CO2, but at the same time warming may accelerate the loss of extant soil carbon, so an accurate estimation of soil carbon stocks and their vulnerability to climate change is required. Here we demonstrate how separating soil carbon into particulate and mineral-associated organic matter (POM and MAOM, respectively) aids in the understanding of its vulnerability to climate change and identification of carbon sequestration strategies. By coupling European-wide databases with soil organic matter physical fractionation, we assessed the current geographical distribution of mineral topsoil carbon in POM and MAOM by land cover using a machine-learning approach. Further, using observed climate relationships, we projected the vulnerability of carbon in POM and MAOM to future climate change. Arable and coniferous forest soils contain the largest and most vulnerable carbon stocks when cumulated at the European scale. Although we show a lower carbon loss from mineral topsoils with climate change (2.5 ± 1.2 PgC by 2080) than those in some previous predictions, we urge the implementation of coniferous forest management practices that increase plant inputs to soils to offset POM losses, and the adoption of best management practices to avert the loss of and to build up both POM and MAOM in arable soils.