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22501. 题目: Harvesting zero waste from co-digested fruit and vegetable peels via integrated fermentation and pyrolysis processes
文章编号: N19022813
期刊: Environmental Science and Pollution Research
作者: Mohamed Soltan, Mohamed Elsamadony, Alsayed Mostafa, Hanem Awad, Ahmed Tawfik
更新时间: 2019-02-28
摘要: The aim of this study is to assess an innovative economic approach for the production of both fermentative hydrogen and biochar from fruit and vegetable peels (FVPs) via fermentation/pyrolysis process. Firstly, in fermentation batches, multi-fermentation of FVPs positively affected the harvested hydrogen yield and COD reduction efficiency, which reached their maximal values of 3.9 ± 0.6 mmol/g_COD and 56.2 ± 4.6% at batch of 25% pea + 25% tomato + 25% banana + 25% orange (M4). Secondly, digestates produced from all batches were pyrolyzed at 500 °C for investigating the potential for biochar production. Based on the characteristics of the pyrolyzed digestate, biochar produced from S1 (spinach) exhibited the highest specific surface area, density, pore volume, biochar production yield, and pyrolysis profit of 28.43 ± 3.95 m²/g, 1.93 ± 0.18 g/cm³, 0.59 ± 0.08 cm³/g, 59.04 ± 2.36%, and 3.66 $/kg_feedstock, respectively. However, the maximum overall profit from both fermentation and pyrolysis processes was 5.21 $/kg_feedstock and was denoted for M4.

22502. 题目: Copper-doped TiO 2 photocatalysts: application to drinking water by humic matter degradation
文章编号: N19022812
期刊: Environmental Science and Pollution Research
作者: Nazli Turkten, Zekiye Cinar, Ayse Tomruk, Miray Bekbolet
更新时间: 2019-02-28
摘要: The aim of this study was to determine the photocatalytic performance of copper-doped TiO₂ (Cu-TiO₂) specimens on the degradation of dissolved organic matter (DOM) represented by a model humic acid (HA). TiO₂ was synthesized by sol-gel method from an alkoxide precursor. Cu-doped TiO₂ specimens containing 0.25 wt% and 0.50 wt% Cu were prepared by wet impregnation method using sol-gel synthesized as well as bare TiO₂ P-25 and characterized by XRD, SEM, XPS, Raman spectroscopy, UV-DRS, and BET measurements. Their photocatalytic activities were evaluated with regard to degradation kinetics of HA in terms of UV-vis and fluorescence spectroscopic parameters and organic contents. HA fluorescence excitation emission matrix (EEM) contour plots indicated that the solar photocatalytic degradation pathway was TiO₂-type specific and Cu dopant content.

22503. 题目: Evaluating Recent Updated Black Carbon Emissions and Revisiting the Direct Radiative Forcing in Arctic
文章编号: N19022811
期刊: Geophysical Research Letters
作者: Xinyi Dong, Qingzhao Zhu, Joshua S. Fu, Kan Huang, Jiani Tan, Matthew Tipton
更新时间: 2019-02-28
摘要: There is significant uncertainty in the global inventory of black carbon (BC). Several recent studies have reported BC emission updates, including the Fire Emission Inventory‐northern Eurasia (FEI‐NE), anthropogenic emission in Russia (RUS), and global natural gas flaring (NGF). Compared with the inventory used by IPCC, these updates are only 10% higher on a global scale but are 3 times greater than previous estimations in Arctic (60°N‐90°N). We applied GEOS‐Chem to examine these emission updates and evaluate their impacts on direct forcing. We found that FEI‐NE may be substantially overestimated, RUS shows no prominent influence on simulation, and NGF noticeably improve simulation performance in the Arctic. Model estimated direct forcing of BC is increased by 30% on the global scale and is 2 times higher in the Arctic through application of these emission updates. This study reveals the urgent need to improve the reliability of emission inventories in the high latitudes, especially over Eurasia.

22504. 题目: Decreasing Trend in Black Carbon Aerosols over the Indian Region
文章编号: N19022810
期刊: Geophysical Research Letters
作者: M. R. Manoj, S. K. Satheesh, K. Krishna Moorthy, Mukunda M. Gogoi, S. Suresh Babu
更新时间: 2019-02-28
摘要: We examine long‐term trends in the near‐surface Black Carbon (BC) mass concentration, using multi‐year primary data obtained from a dense network (ARFINET) of observatories over the Indian region. We report for the first time the statistically significant decreasing trend in BC mass concentration, based on primary data from this region, at an average rate of ~242 ± 53 ng m^‐3 yr^‐1during the period 2007‐2016. This finding contrasts with the generally increasing trend in the columnar Aerosol Optical Depth (AOD), reported earlier, and the steadily increasing trend in anthropogenic activities over this region. The roles of different possible mechanisms, including possible changes in the vertical re‐distribution of aerosols are discussed. Over the period 2007‐2015, a significant though weak, increasing trend is seen in the contribution from aerosols above 1 km, to the columnar AOD. These observations imply possible long‐term climate consequences.

22505. 题目: Effects of land use change on organic carbon dynamics associated with soil aggregate fractions on the Loess Plateau, China
文章编号: N19022809
期刊: Land Degradation & Development
作者: Zekun Zhong, Xinhui Han, Yadong Xu, Wei Zhang, Shuyue Fu, Weichao Liu, Chengjie Ren, Gaihe Yang, Guangxin Ren
更新时间: 2019-02-28
摘要: Organic carbon (OC) sequestration through soil aggregation is an important aspect of land use change/conversion (LUCC) influencing terrestrial ecosystem C cycle, although little is known on the changes in aggregate dynamics and their contributions to OC accumulation after LUCC in regions with serious soil erosion. Therefore, bulk soil under four land uses [farmland (FL) and three vegetated soils converted from FL 42 years ago: Robinia pseudoacacia (RP42a), Caragana korshinskii (CK42a), and abandoned land (AL42a)] in the Loess Plateau, China, was collected, separated into seven aggregate size fractions, and examined for OC content. Farmland conversion into AL42a, CK42a, and RP42a increased macro‐ (>2 mm) and mesoaggregate (2–0.25 mm) proportions, mean weight diameter, and geometric mean diameter but decreased microaggregates (0.25–0.053 mm) amount. Bulk soil and aggregates OC content and stock varied with soil depth and land use types, but were usually highest in RP42a. Mesoaggregates contained higher OC content and stock than other aggregates at 0–20 cm depth under all land uses. Increases in the OC stocks of mesoaggregates accounted for 46% and 85 % of the increase in bulk soil OC stocks at 0–20 and 20–40 cm depth, respectively. Thus, soil OC accumulation after LUCC is mainly due to increased OC stock within mesoaggregates, which is further attributed to increased mesoaggregate proportions. Overall, vegetation restoration promotes the physical protection of OC by increasing soil aggregation, being a management option to enhance the C sequestration potential in ecological fragile regions.

22506. 题目: Selective adsorption of soil humic acid on binary systems containing kaolinite and goethite: Assessment of sorbent interactions
文章编号: N19022808
期刊: European Journal of Soil Science
作者: H. F. Chen, L. K. Koopal, J. L. Xu, M.X. Wang, W. F. Tan
更新时间: 2019-02-28
摘要: Inorganic colloids are ubiquitous in soils and coexist as simple mixtures or as strong associations of particles. The coexisting inorganic colloids with a variety of active sites can selectively adsorb humic substance and thus affect the availability and mobility of organic matter. To investigate the selective adsorption behaviour of organic matter by coexisting inorganic colloids, humic acid (JGHA) extracted from soil, a synthetic association (KGA) and a mixture (KGM) of kaolinite and goethite were prepared and studied. With the adsorption expressed in μmol m^‐2, the adsorption affinity of JGHA on KGA (initial slope of isotherms) was slightly higher than that on KGM, although KGM could adsorb more JGHA molecules at larger JGHA concentrations. At pH 4, JGHA adsorbed on the kaolinite edges and goethite through electrostatic attraction and ligand exchange, and on the kaolinite siloxane plates through hydrophobic interaction. At pH 6 and 8, the adsorption occurred only on the kaolinite siloxane plates and goethite. The overall average adsorption Gibbs energies were moderately negative, and comprised a strongly negative average overall molar entropy and a negative average overall molar entropy contribution. Thus, overall JGHA adsorption on KGA and KGM was enthalpy controlled. The large exothermic enthalpy gains and entropy losses were due to electrostatic attraction and ligand exchange. The entropy gains because of hydrophobic attraction between JGHA and the kaolinite siloxane plates is masked by the larger entropy loss of adsorption on the hydrophilic surface. The fractions of JGHA with molar mass > ~12.9 kDa (1 Da = 1 g mol^‐1) were adsorbed selectively by KGM, whereas the fractions < ~12.9 kDa were selectively adsorbed by KGA. High molar mass and hydrophobic fractions adsorb selectively on the kaolinite siloxane plates, whereas low molar mass fractions with hydrophilic groups adsorb selectively on goethite and the kaolinite edges.

22507. 题目: Influence of biochar particle size on biota responses
文章编号: N19022807
期刊: Ecotoxicology and Environmental Safety
作者: M. Prodana, C. Silva, C. Gravato, F.G.A. Verheijen, J.J. Keizer, A.M.V.M. Soares, S. Loureiro, A.C. Bastos
更新时间: 2019-02-28
摘要: Despite the increasing interest for biochar as a soil amendment, a knowledge gap remains on its impacts on non-target soil and aquatic species. We hypothesised that biochar particle size and application rate can play a role in the toxicity to biota. Pine woodchip biochar was incorporated in a clean soil at three particle size classes: small (<0.5 mm), medium (1–2 mm), and large (<4 mm), and at two concentrations: 1% and 6% w/w. A laboratory screening with earthworm Eisenia andrei avoidance behaviour bioassay was carried out to test the most adequate application rates, particle sizes and soil-biochar pre-incubation period. Thereafter, a 28-day greenhouse microcosm experiment was conducted as an ecologically more representative approach. Survival, vertical distribution and weight changes of E. andrei, and bait-lamina consumption were recorded. Soil leachates from the microcosms were collected to evaluate their impact on Daphnia magna immobilisation and Vibrio fischeri (Microtox®) bioluminescence. A feeding experiment with E. andrei was also performed to address earthworm weight changes and to conduct a screening of PAH-type metabolites in their tissue. The 6% <0.5 mm treatment pre-incubated for 96 h induced significant avoidance of the earthworms. Significantly lower bait-lamina consumption was observed in microcosms for the 6% <0.5 mm treatment. Moreover, particle size was a statistically significant factor regarding the loss of weight in the feeding experiment and higher concentration of naphthalene-type metabolites detected in E. andrei tissue, when exposed to <0.5 mm biochar particles. The leachates had no adverse effects on the aquatic species. The results suggest that particles <0.5 mm of pine woodchip biochar can pose sub-lethal effects on soil biota.

22508. 题目: Magnetic biochar catalysts from anaerobic digested sludge: Production, application and environment impact
文章编号: N19022806
期刊: Environment International
作者: Yi-di Chen, Shunwen Bai, Ruixiang Li, Guanyong Su, Xiaoguang Duan, Shaobin Wang, Nan-qi Ren, Shih-Hsin Ho
更新时间: 2019-02-28
摘要: Regulated disposal or re-utilization of dewatered sludge is of economic benefits and can avoid secondary contamination to the environment; however, feasible and effective management strategies are still lacking. In this study, a peroxydisulfate/zero-valent iron (PDS-ZVI) system is proposed to destroy proteins in soluble extracellular polymeric substances (S-EPS) and loosely bound EPS (LB-EPS) in anaerobic digested sludge (ADS) to improve the dewaterability. Moreover, ADS derived biochars supported via iron oxides (Fe-ADSBC) were generated by dewatering and thermal annealing. Intriguingly, the iron species was discovered to gradually transform from Fe₃O₄ to FeO with increased pyrolysis temperatures from 600 to 1000 °C. The manipulated iron species on the biochar can remarkably impact the catalytic activity in PDS activation and degradation of sulfamethazine (SMT). The in situ radical scavenging and capturing tests revealed that the principal reactive oxygen species (ROS) in Fe-ADSBC/PDS system experienced a variation from OH into SO₄⁻ at higher annealing temperature (1000 °C). In addition, the carbonaceous ADSBC can promote the catalytic activity of iron oxides by synergistically facilitating the adsorption of reactants and charge transfer through C-O-Fe bonds at the interfaces. This study enables the first insights into the properties and catalytic performance of Fe-ADSBC, meanwhile unveils the mechanism, reaction pathways, and environmental impacts of the ultimate transformation products (TPs) from SMT degradation in the Fe-ADSBC/PDS system. The study also contributes to developing value-added green biochar catalysts from bio-wastes towards environmental purification.
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22509. 题目: Mechanisms of algal biomass input enhanced microbial Hg methylation in lake sediments
文章编号: N19022805
期刊: Environment International
作者: Pei Lei, Luís M. Nunes, Yu-Rong Liu, Huan Zhong, Ke Pan
更新时间: 2019-02-28
摘要: Eutrophication is a major environmental concern in lake systems, impacting the ecological risks of contaminants and drinking water safety. It has long been believed that eutrophication and thus algal blooms would reduce methylmercury (MeHg) levels in water, as well as MeHg bioaccumulation and trophic transfer (e.g., by growth dilution). In this study, however, we demonstrated that algae settlement and decomposition after algal blooms increased MeHg levels in sediments (54–514% higher), as evidenced by the results from sediments in 10 major lakes in China. These could in turn raise concerns about enhanced trophic transfer of MeHg and deterioration of water quality after algal blooms, especially considering that 9 out of the 10 examined lakes also serve as drinking water sources. The enhanced microbial MeHg production in sediments could be explained by the algal organic matter (AOM)-enhanced abundances of microbial methylators as well as the input of algae-inhabited microbes into sediments, but not Hg speciation in sediments: (1) Several AOM components (e.g., aromatic proteins and soluble microbial by product-like material with generally low molecular weights), rather than the bulk AOM, played key roles in enhancing the abundances of microbial methylators. The copies of Archaea-hgcA methylation genes were 51–397% higher in algae-added sediments; thus, MeHg production was also higher. (2) Input of algal biomass-inhabited microbial methylators contributed to 2–21% of total Archaea-hgcA in the 10 lake sediments with added algal biomass. (3) However, AOM-induced changes in Hg speciation, with implications on Hg availability to microbial methylators, played a minor role in enhancing microbial Hg methylation in sediments as seen in X-ray absorption near edge structure (XANES) data. Our results suggest the need to better understand the biogeochemistry and risks of contaminants in eutrophic lakes, especially during the period of algae settlement and decomposition following algal blooms.
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22510. 题目: Dissolved organic matter derived from rape straw pretreated with selenium in soil improves the inhibition of Sclerotinia sclerotiorum growth
文章编号: N19022804
期刊: Journal of Hazardous Materials
作者: Wei Jia, ChengXiao Hu, JiaYang Xu, JiaJia Ming, YuanYuan Zhao, MiaoMiao Cai, XueCheng Sun, XinWei Liu, XiaoHu Zhao
更新时间: 2019-02-28
摘要: Sclerotinia sclerotiorum (S. sclerotiorum) is a soil-borne pathogen with broad host range. Dissolved organic matter (DOM) plays a vital role in regulating microbial activity in soil. Exogenous selenium (Se) inhibits plant pathogen growth and enhances the capacity of plants to resist disease. DOM from rape straw with Se treated in soil (RSDOM_Se) was extracted, and the inhibitory effect on S. sclerotiorum growth was investigated. RSDOM_Se inhibited S. sclerotiorum growth, which not only caused severe damage to S. sclerotiorum hyphae but also enhanced soluble protein leakage, thereby improving the growth inhibition ratio by 20.9%. As the action in intercellular, RSDOM_Se led to a significant increase in oxalic acid and decrease in CWDE (cell wall-degrading enzyme, which helps pathogens to invade plants) activities, downregulation of Bi1 (BAX inhibitor-1, required for S. sclerotiorum virulence), Ggt1 (γ-glutamyl transpeptidase, regulates the ROS antioxidant system), CWDE2 and CWDE10 gene expression levels, compared with non-Se treated RSDOM (RSDOM_N). Eight metabolites upregulated in RSDOM_Se were identified by GC-TOF-MS, and among these metabolites, fumaric acid, maleic acid, malonic acid, mucic acid, saccharic acid, succunic acid and phenylacetic acid showed significant inhibition on S. sclerotiorum growth. These findings provide valuable insight into a new approach for developing eco-friendly fungicides.
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22511. 题目: Role of temperature on the development of hypoxia in blackwater from grass
文章编号: N19022803
期刊: Science of The Total Environment
作者: Chamindra L. Vithana, Leigh A. Sullivan, Troy Shepherd
更新时间: 2019-02-28
摘要: In eastern Australia the development of hypoxic blackwater/floodwater and its detrimental consequences are more common in summer than winter. This study examined the effect of temperature on the development of hypoxic conditions which was determined as biochemical oxygen demand (BOD) in floodwater when pasture grass (a source containing labile organic carbon) was inundated. Labile dissolved organic carbon (DOC) in blackwater is one of the main factors that contribute to the development of hypoxic conditions. Temperature plays a key role on the microbial mineralization of labile DOC and hence the development of hypoxic conditions. Prolonged flooding at different seasons (having different temperatures) was simulated in the laboratory by incubating fresh pasture grass cuttings with river water and soil at three different temperatures (20 °C, 27.5 °C and 35 °C) for 20 days. Although this study shows that elevated ambient temperatures can result in more rapid development of hypoxic conditions during the first week of flood peak, it is evident that blackwater formed at relatively moderate ambient temperatures (e.g. 20 °C) has a similar potential to deoxygenate the receiving water bodies, especially after one week's duration of flood peak.
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22512. 题目: Geochemical controls on the distribution of mercury and methylmercury in sediments of the coastal East China Sea
文章编号: N19022802
期刊: Science of The Total Environment
作者: Lu Zhao, Rui Wang, Chi Zhang, Daqiang Yin, Shouye Yang, Xiangtong Huang
更新时间: 2019-02-28
摘要: We examined the spatial and vertical distribution of total mercury (THg) in 119 surface sediment samples and 4 sediment cores from the coastal East China Sea. The THg concentrations (3.6–69.2 μg kg⁻¹, average 34.7 μg kg⁻¹) in surface sediments exhibited a decreasing trend from the inner shelf towards the outer shelf. The THg levels in sediment cores showed a significant increasing trend from the bottom to the top layer. Both the spatial and vertical distribution of THg indicates the impacts of anthropogenic inputs. The THg concentrations in the surface sediments of Yangtze River estuary were strongly correlated with sediment particle size and organic matter, governing by the Yangtze River inputs. The relatively higher THg levels in the surface sediments of southern inner shelf were attributed to the stronger binding affinity of the finer-grained sediments, the nature of organic matter, as well as local inputs. The spatial distribution of toxic methylmercury (MeHg) was distinct from THg, controlled by direct terrigenous MeHg inputs and in situ MeHg formation. The net Hg methylation potential (indicated by MeHg/THg ratio) in surface sediments were significantly influenced by both geochemical factors (DO, temperature and water depth) and the physicochemical properties of sediments (grain size, TOC, S, Fe₂O₃ and MnO), and exhibited the highest correlation with TOC, suggesting the key role of organic matter in governing net MeHg production. Moreover, sites with high MeHg/THg ratios mainly occurred within the summer hypoxia zones adjacent to the Yangtze River estuary, suggesting special attention on Hg ecological risks should be paid in this region.
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22513. 题目: Innovative drinking water treatment techniques reduce the disinfection-induced oxidative stress and genotoxic activity
文章编号: N19022801
期刊: Water Research
作者: Johan Lundqvist, Anna Andersson, Anders Johannisson, Elin Lavonen, Geeta Mandava, Henrik Kylin, David Bastviken, Agneta Oskarsson
更新时间: 2019-02-28
摘要: Disinfection of drinking water using chlorine can lead to the formation of genotoxic by-products when chlorine reacts with natural organic matter (NOM). A vast number of such disinfection by-products (DBPs) have been identified, making it almost impossible to routinely monitor all DBPs with chemical analysis. In this study, a bioanalytical approach was used, measuring oxidative stress (Nrf2 activity), genotoxicity (micronucleus test), and aryl hydrocarbon receptor (AhR) activation to evaluate an innovative water treatment process, including suspended ion exchange, ozonation, in-line coagulation, ceramic microfiltration, and granular activated carbon. Chlorination was performed in laboratory scale after each step in the treatment process in order to investigate the effect of each treatment process to the formation of DBPs. Suspended ion exchange had a high capacity to remove dissolved organic carbon (DOC) and to decrease UV absorbance and Nrf2 activity in non-chlorinated water. High-dose chlorination (10 mg Cl₂ L^-1) of raw water caused a drastic induction of Nrf2 activity, which was decreased by 70% in water chlorinated after suspended ion exchange. Further reduction of Nrf2 activity following chlorination was achieved by ozonation and the concomitant treatment steps. The ozonation treatment resulted in decreased Nrf2 activity in spite of unchanged DOC levels. However, a strong correlation was found between UV absorbing compounds and Nrf2 activity, demonstrating that Nrf2 inducing DBPs were formed from pre-cursors of a specific NOM fraction, constituted of mainly aromatic compounds. Moreover, high-dose chlorination of raw water induced genotoxicity. In similarity to the DOC levels, UV absorbance and Nrf2 activity, the disinfection-induced genotoxicity was also reduced by each treatment step of the innovative water treatment technique. AhR activity was observed in the water produced by the conventional process and in the raw water, but the activity was clearly decreased by the ozonation step in the innovative water treatment process.
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22514. 题目: Combined biochar and nitrogen fertilization at appropriate rates could balance the leaching and availability of soil inorganic nitrogen
文章编号: N19022719
期刊: Agriculture, Ecosystems & Environment
作者: Shuailin Li, Shuo Wang, Zhouping Shangguan
更新时间: 2019-02-27
摘要: Biochar has been proposed to ameliorate soil properties and plant growth. However, it remains unclear how the interaction between biochar and nitrogen (N) fertilizer impacts soil inorganic nitrogen (SIN) leaching and availability in dryland systems. Therefore, a two-year field experiment was carried out on the Loess Plateau in northern China to study the effects of biochar combined with N fertilizer on the leaching and availability of SIN. Biochar applied at 0, 20 and 40 t ha⁻¹ (B0, B1 and B2, respectively) interacted with three N fertilization levels (0, 120 and 240 kg N ha⁻¹; N0, N1 and N2, respectively). Winter wheat (Triticum aestivum L.) was cultivated in a winter wheat-summer fallow cropping system. We measured wheat aboveground biomass and residual SIN in the soil profile (0–60 cm at 10 cm intervals) using standard extraction methods (2 M KCL, shaking at 25 °C for 1 h). Additionally, to ascertain whether field-aged biochar captured SIN and to determine residual SIN availability, we also used a modified extraction method (2 M KCL, shaking at 60 °C for 2 h) and ion exchange membranes (IEMs) to extract SIN from plow layer soil (0–20 cm). Our results indicated that biochar application alone in the absence of N fertilization had no significant effect on wheat biomass or residual SIN in the soil profile. However, compared with the application of N fertilizer alone, the application of biochar at 20 t ha^-1 combined with N fertilizer not only increased wheat biomass by 12.2–13.8% but also significantly decreased residual NO₃⁻-N in the subsoil by 13.2–74.7%. Nevertheless, long-term N fertilization at 240 kg N ha^-1 led to large amounts of residual NO₃⁻-N without a significant increase in crop biomass, which inevitably increased the risk of leaching during the fallow period. Although the application of biochar at 40 t ha^-1 combined with N fertilizer more effectively decreased residual SIN in the subsoil, this approach was impractical because it decreased wheat biomass. Furthermore, the difference between NO₃⁻-N extracted via the modified method and via the standard method increased with biochar application under each N level. Thus, field-aged biochar absorbed a certain amount of NO₃⁻-N, thereby sequestering N in the soil after two years of N fertilization. Hence, biochar could reduce the residual NO₃⁻-N available for leaching during the fallow period. However, notably, overuse of biochar could reduce the amount of NO₃⁻-N available not only for leaching but also for crops. Ultimately, the application of biochar at 20 t ha^-1 combined with N fertilization at 120 kg N ha^-1 is a promising dual-win strategy for improving N availability while concurrently mitigating SIN leaching.

22515. 题目: Soil properties on sub-Antarctic Macquarie Island: Fundamental indicators of ecosystem function and potential change
文章编号: N19022718
期刊: CATENA
作者: Brian R. Wilson, Susan C. Wilson, Brian Sindel, Laura K. Williams, Kirsten L. Hawking, Justine Shaw, Matthew Tighe, Quan Hua, Paul Kristiansen
更新时间: 2019-02-27
摘要: We examined the nature and properties of soils on Australian sub-Antarctic Macquarie Island to determine key environmental factors driving their distribution, development and change. We provide the first classification of these soils using Australian and international (WRB) systems while combining elemental, stable and radio-isotope analysis to interpret processes of soil formation and key controlling environmental factors. Soil organic carbon (SOC) and total nitrogen (TN) concentrations across the island were influenced largely by elevation and topographic position with coastal soils and wetter depressions containing more SOC and TN compared with drier and higher elevation locations. Soils on the high, exposed plateau of the island contained low SOC and TN concentrations by comparison. Results suggested that soils of the coastal zone are subject to ongoing aggradation with significant inputs of nutrient, particularly extractable P (Ext P), from oceanic and especially avifauna sources. Nutrient subsidy was concentrated on coastal margins and the more sheltered eastern side of the island, diminishing significantly with increasing elevation and distance from the coast. Soils of the central plateau contained very low Ext P concentrations throughout the profile and appear to be relic if not degrading. Further comprehensive soil mapping, classification and monitoring across Macquarie Island will elucidate the important role that soils serve for healthy ecosystem function in these sub-Antarctic environments and provide early warning indicators of significant environmental change.

22516. 题目: Comparison of efficacies of peanut shell biochar and biochar-based compost on two leafy vegetable productivity in an infertile land
文章编号: N19022717
期刊: Chemosphere
作者: Bingjie Liu, Zhaohui Cai, Yuchan Zhang, Guocheng Liu, Xianxiang Luo, Hao Zheng
更新时间: 2019-02-27
摘要: The soils in northwest China are severely stressed with nutrient deficiency and water depletion, thus limiting crop production and sustainable agricultural development. Biochar-based amendments, tailored for specific soil issues, have raised great public interest for soil improvement and carbon sequestration. Peanut shell-derived biochar (PBC) and PBC-based amendment (PAD) obtained from composting were added at concentrations of 0%, 1.5%, 3%, and 5% (w/w) into light sierozem soil to compare their effects on growth of crown daisy (Chrysanthemum coronarium L.) and leaf lettuce (Lactuca sativa var longifoliaf L.). PBC had no significant effect on the yields of the two vegetables due to the second season growth, while addition of low concentrations of PAD (≤3%) significantly increased their yields by 15.8%–107%. The positive effect of PAD was primarily attributed to the improved soil qualities (e.g., water holding capacity (WHC), soil organic matter (SOM), electrical conductivity (EC)) and increased contents of available macronutrients (e.g., P and K), and micronutrients (e.g., B, Zn and Mn). However, addition of 5% PAD decreased the yield of crown daisy by 26.9% compared to that grown in untreated soil because of surplus nutrient input resulting in high EC. Overall, our findings demonstrated that the designed PAD synthesized from PBC compost had the potential to ameliorate the infertility in the soil and thus to improve vegetable yield.
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22517. 题目: Alleviation of cadmium accumulation in maize (Zea mays L.) by foliar spray of zinc oxide nanoparticles and biochar to contaminated soil
文章编号: N19022716
期刊: Environmental Pollution
作者: Muhammad Rizwan, Shafaqat Ali, Muhammad Zia ur Rehman, Muhammad Adrees, Muhammad Arshad, Muhammad Farooq Qayyum, Liaqat Ali, Afzal Hussain, Shahzad Ali Shahid Chatha, Muhammad Imran
更新时间: 2019-02-27
摘要: Due to the increase in area of cadmium (Cd)-contaminated soils worldwide, effective measures are necessary to minimize the Cd accumulation in cereals including maize (Zea mays L.) plant. A study was therefore performed to explore the effectiveness of foliar spray of zinc oxide (ZnO) nanoparticle (NPs) alone (0, 50, 75, 100 mg/L) or combined with soil application of biochar (1.0% w/w) on biomass, antioxidant enzyme activity and Cd concentrations in maize plants grown on a Cd-contaminated soil. The results depicted that ZnO NPs alone or in combination with biochar improved the height of maize plants, number of leaves, shoot and roots dry biomass, chlorophyll concentrations and gas exchange attributes. All the amendments reduced the electrolyte leakage, malondialdehyde, and hydrogen peroxide contents while improved the activities of antioxidant enzymes in leaf and roots of maize over the control. The application of 50, 75 and 100 mg/L ZnO NPs reduced the Cd contents in shoots by about 12%, 23, and 61%, and in roots by 18%, 33%, and 53%, respectively, over the control. The Cd concentrations in shoot decreased by 15%, 28%, and 68% and in roots by 14%, 35, and 55% after biochar combined with foliar spray of 50, 75 and 100 mg/L ZnO NPs, respectively. All the amendments improved the Zn concentrations in maize shoots and roots whereas reduced the soil bioavailable Cd. Overall, biochar combined with foliar spray of ZnO NPs could be recommended for safely growing the crops on Cd-contaminated soils.
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22518. 题目: Mercury bioaccumulation in tilefish from the northeastern Gulf of Mexico 2 years after the Deepwater Horizon oil spill: Insights from Hg, C, N and S stable isotopes
文章编号: N19022715
期刊: Science of The Total Environment
作者: Vincent Perrot, William M. Landing, R. Dean Grubbs, Vincent J.M. Salters
更新时间: 2019-02-27
摘要: Mercury (Hg) concentration in fish of the Gulf of the Mexico (GoM) is a major concern due to the importance of the GoM for U.S. fisheries. The Deepwater Horizon (DWH) oil spill in April 2010 in the northern GoM resulted in large amounts of oil and dispersant released to the water column, which potentially modified Hg bioaccumulation patterns in affected areas. We measured Hg species (methylmercury (MMHg) and inorganic Hg (IHg)) concentrations, and light (C, N and S) and Hg stable isotopes in muscle and liver tissues from tilefish (Lopholatilus chamaleonticeps) sampled in 2012 and 2013 along the shelf break of the northeastern GoM. Fish located close to the mouth of the Mississippi River (MR) and northwest of the DWH well-head (47 km) showed significantly lower Hg levels in muscle and liver than fish located further northeast of the DWH (>109 km), where 98% of tilefish had Hg levels in the muscle above US consumption advisory thresholds (50% for tilefish close to the DWH). Differences in light and Hg stable isotopes signatures were observed between these two areas, showing higher δ¹⁵N, and lower δ²⁰²Hg, Δ¹⁹⁹Hg and δ³⁴S in fish close to the DWH/MR. This suggests that suspended particles from the MR reduces Hg bioavailability at the base of the GoM food chains. This phenomenon can be locally enhanced by the DWH that resulted in increased particles in the water column as evidenced by the marine snow layer in the sediments. On the other hand, freshly deposited Hg associated with organic matter in more oligotrophic marine waters enhanced Hg bioaccumulation in local food webs. Comparing Hg isotopic composition in liver and muscle of fish indicates specific metabolic response in fish having accumulated high levels of MMHg.
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22519. 题目: Biotransformation of antibiotics: exploring the activity of extracellular and intracellular enzymes derived from wastewater microbial communities
文章编号: N19022714
期刊: Water Research
作者: Michael T. Zumstein, Damian E. Helbling
更新时间: 2019-02-27
摘要: Evaluating the activity of extracellular and intracellular enzymes derived from wastewater microbial communities is essential to improve our fundamental understanding of micropollutant removal during wastewater treatment. To study biotransformations with respect to enzyme biogeography, we developed a method to separate soluble extracellular, extracellular polymeric substance (EPS)-bound, and intracellular enzymes from wastewater microbial communities and assessed the protease and peptidase activity of the resulting enzyme pools. We also evaluated the biotransformation of six antibiotics (amoxicillin, ampicillin, clindamycin, daptomycin, linezolid, and vancomycin) in each enzyme pool because we expect that the kinetics, pathways, and biogeography of antibiotic biotransformations influence the selection of antibiotic resistance within wastewater microbial communities and in downstream environments. Our results demonstrated that biotransformation rate constants varied among the tested antibiotics, and that the observed rank order was consistent across three wastewater treatment plants. Importantly, many of the observed biotransformations eliminated the functional groups associated with antibiotic activity. Furthermore, we found that β-lactam hydrolysis and daptomycin hydrolysis were catalyzed by enzymes extracted from the EPS, while none of the tested antibiotics were biotransformed by soluble extracellular enzymes. Finally, our results demonstrated that the number of enzyme-catalyzed antibiotic transformations was larger for intracellular than for extracellular enzymes. Together, this study provides novel insights on the kinetics, pathways, and biogeography of antibiotic biotransformations performed by wastewater microbial communities and can be used to inform pathway prediction or the development of biodegradable chemicals.
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22520. 题目: The variation of flocs activity during floc breakage and aging, adsorbing phosphate, humic acid and clay particles
文章编号: N19022713
期刊: Water Research
作者: Mingyu Wu, Wenzheng Yu, Jiuhui Qu, John Gregory
更新时间: 2019-02-27
摘要: The mechanism of removal of humic acid, phosphate and kaolin particles by coagulation with alum and PACl or adsorption by their pre-formed precipitates was investigated, and it was found that the coagulation mechanisms for monomeric Al at neutral pH and polymeric Al₁₃ at alkaline pH were very similar. The removal of phosphate and humic acid by coagulation with alum or PACl did not change with stirring time (between 1 min and 15 min), independent of the dose and species of coagulants. However, for adsorption of these impurities by pre-formed precipitates, the results were significantly different. Both Al³⁺ and nano-sized Al₁₃ could precipitate and form aggregates at pH 7 and pH 9, respectively, and their precipitates became less active (fewer binding sites on the surface of precipitate) with the increase of shear time or shear rates before adsorbing pollutants. Thus, although the total surface area increased (the average size of flocs became smaller) at higher applied shear rates or longer shear time, the removal efficiency of humic acid and phosphate decreased. Also, from the MW distributions, it was confirmed that less humic acid was removed by the adsorption on alum precipitate pre-formed with longer shear time. Chemical groups (OH₂and OH) on the surface of precipitate determined the removal efficiency of phosphate and humic acid, and the activity of precipitate become lower as a result of higher applied shear and longer shear time. This is confirmed be due to some crystallization of the amorphous precipitate, forming inactivated hydroxyl. When kaolin was added 10 min after the alum or PACl precipitate formed, the precipitates captured kaolin particles only on their surface, whereas when alum was added to kaolin suspensions particles were trapped within the growing flocs. When alum/kaolin flocs were broken at high shear rate re-growth of flocs decreased with increasing shear time, but after a short breakage period, long aging of broken flocs had little effect on floc regrowth.
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