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Copper and Zinc in Rhizosphere Soil and Toxicity Potential in White Oats (Avena sativa) Grown in Soil with Long-Term Pig Manure Application
2019
Benedet, Lucas | De Conti, Lessandro | Lazzari, Cleiton Junior Ribeiro | Júnior, Vilmar Müller | Dick, Deborah Pinheiro | Lourenzi, Cledimar Rogério | Lovato, Paulo Emílio | Comin, Jucinei José | Tiecher, Tadeu Luis | Ricachenevsky, Felipe Klein | Brunetto, Gustavo
Successive applications of pig manure increase Cu and Zn contents in soils and may cause toxicity to plants. However, plants may have defense strategies that reduce Cu and Zn availability in rhizosphere soil. The study aimed to evaluate growth of white oats (Avena sativa) and Cu and Zn availability in rhizosphere soil subjected to long-term applications of pig slurry (PS) and pig deep litter (PL). The study was carried out with samples of a Typic Hapludalf soil from an 11-year experiment with annual fertilization of 180 kg N ha⁻¹ as pig slurry (PS180) and pig deep litter (PL180) and a control (C) treatment. White oats were grown in pots with soil collected at 0.0–0.10 m depth. Thirty-five and 70 days after emergence (DAE), rhizosphere (RS) and bulk soil (BS) were analyzed to determine Cu and Zn availability. Plant growth, tissue Cu and Zn concentration, and content (concentration X dry weight) were measured. The application of pig manure for 11 years increased available soil Cu and Zn, as well as tissue concentration and content. Dry matter yield and plant height in PL180 were similar to those found in plants grown in the control treatment, while plants grown in PS180 had higher dry matter than in C. We found few differences in soil chemical characteristics and Cu and Zn contents between RS and BS. The high Cu concentrations in roots, especially in soil treated with PL180, show that Cu retention in the roots prevents excess Cu transport to white oat shoots.
Mostrar más [+] Menos [-]Access to Natural Substrates in Urban Streams Does Not Counter Impoverishment of Macroinvertebrate Communities: a Comparison of Engineered and Non-engineered Reaches
2019
Reid, D. J. | Tippler, C.
Urban streams are degraded through multiple mechanisms, including severely altered flow regimes, elevated concentrations of waterborne contaminants, removal of riparian vegetation and the loss of a mosaic of heterogeneous aquatic habitats. Engineering of urban stream reaches using concrete is a widespread and extreme case of deliberate alteration of flow regimes and concomitant habitat simplification. To assess the effect of such engineering practices on stream ecosystems, we compared aquatic macroinvertebrate communities from concrete-lined engineered urban reaches, non-engineered urban reaches with natural substrates and reference reaches flowing through minimally disturbed forested subcatchments and with natural substrates, in the Sydney metropolitan region, Australia. The communities from all urban reaches were impoverished and distinctly different from more diverse communities in forested reference reaches. Despite low aquatic habitat heterogeneity, engineered urban reaches had very high abundances of Diptera and some other tolerant taxa. Diptera and/or Gastropoda were dominant in non-engineered urban reaches. Multivariate community structures were dissimilar between the urban reaches and forested reference reaches and between non-engineered and engineered urban reaches. However, the low family-level richness and SIGNAL scores in both urban reach types indicated they were severely ecological impaired, whether engineered or not. Most macroinvertebrate taxa in the regional pool that were hardy enough to inhabit urban reaches with natural substrates were also present in nearby concreted reaches. The results add weight to the growing evidence that in urban landscapes, regional-scale changes in water quality and flow regimes limit the establishment of diverse macroinvertebrate communities, which cannot be addressed through the provision of increased reach-scale habitat heterogeneity.
Mostrar más [+] Menos [-]Calcined Eggshell as a P Reactive Media Filter—Batch Tests and Column Sorption Experiment
2019
Bus, Agnieszka | Karczmarczyk, Agnieszka | Baryła, Anna
The goal of the study was to assess the sorption properties of calcined eggshells (CEs) as a P reactive media filter. The CEs were calcined in a temperature of 900 °C. A double stage test was performed: batch studies (kinetic and equilibrium) and small-scale column experiment. The estimation of optimal mass ratio of CEs for perspective usage was the additional benefit of column experiment. The short kinetic tests showed that 5 min of contact time with solution of initial concentration of 6.020 mgP-PO₄ L⁻¹ is enough to reduce the P-PO₄ in 100%. The equilibrium studies were conducted with P-PO₄ solution of 6.020 to 977.7 mg L⁻¹ with contact time of 30 min. The obtained data was compensated by non-linear regression using the Marquardt algorithm in the Statgraphics Centurion XVI. The eggshell calcined characterized by high sorption capacity (Sₘₐₓ = 72.87 mg g⁻¹) obtained from the Langmuir isotherm model with a good fit (96.77%). To choose the appropriate ratio of a sand filter to eggshells amendment, four small columns were constructed and fed with P-PO₄ solution (Cᵢₙ ≈ 5 mg L⁻¹). The percentage mass (m/m) of CEs in the columns was 0.0 (the reference one); 1.0; 2.5; and 5.0. The unit sorption obtained during 95 days of column experiment was 10.668, 4.277, and 2.286 mg P-PO₄ g⁻¹ for 1.0, 2.5, and 5.0%, respectively. For practical implementation, the most recommended addition seems to be 1% of CEs. It corresponds, e.g., to the mass of 49 kg CEs for septic tank system.
Mostrar más [+] Menos [-]Green vehicle adoption behavior among low-income households: evidence from coastal Malaysia
2019
Al Mamun, Abdullah | Masud, Muhammad Mehedi | Fazal, Syed Ali | Muniady, Rajennd
In an attempt to mitigate the effects of extreme natural events caused by greenhouse gases (GHGs), a significant number of researchers and environmentalists have repeatedly stressed the importance of implementing protective measures, including the promotion of green consumption. This study examined the elements that motivated the willingness and the practice of green behavior (GB) among low-income households in coastal Peninsular Malaysia. To meet the research objectives, this study adopted the survey questionnaire method to collect data from 380 low-income households. The findings revealed that self-efficacy (SE) and environmental concerns (EC) have statistically significant effects on the attitude toward green products (ATT), while subjective norms (SN) and perceived behavioral control (PBC) have influence on the intention of green vehicles. Eventually, the study discovered the effects of the intention to adopt green vehicle on green vehicle adoption behavior. Hence, the findings of this study provide new insights for policymakers in Malaysia to place more emphasis on improving consumer attitudes, social standards, and PBC, which will ultimately contribute to the adoption of environment-friendly vehicles. In addition, car manufacturers should support this program by designing products and options that would encourage those in the low-income group to replace their conventional vehicles with green alternatives in Malaysia.
Mostrar más [+] Menos [-]Cadmium Accumulation in Peruvian Cacao (Theobroma cacao L.) and Opportunities for Mitigation
2019
Zug, Katharina Laila Marie | Huamaní Yupanqui, Hugo Alfredo | Meyberg, Frank | Cierjacks, Julia Susanne | Cierjacks, Arne
Crops are the main source of toxic cadmium for humans due to uptake from naturally or anthropogenically polluted soils. Chronic Cd ingestion causes kidney, liver, and skeletal damage along with an increased risk of cancer. Cacao is known to accumulate Cd and may therefore be potentially harmful to human health. Consequently, cocoa production on intensely polluted soils should be avoided. Cocoa products from South America in particular often exceed the limits for Cd, but the factors that drive Cd uptake are as yet poorly studied. In this study, we measured Cd concentrations in defatted cocoa powder from unfermented seeds of 40 different trees on 20 farms in the Huánuco Region, Peru, and associated the Cd levels with the farms’ soil, field management, and nearby vegetation diversity. The mean Cd concentration found in cocoa of the study region was 2.46 mg kg⁻¹ with a range of 0.2–12.56 mg kg⁻¹. The maximum content measured was an order of magnitude higher than the allowed limit of 1.5 mg kg⁻¹ and was the highest reported so far in the literature. Soil Cd content was the most relevant driver of Cd concentration in cacao. In addition, fertilizer use caused significantly higher Cd concentration in cocoa. Higher biodiversity of herbs was positively correlated with Cd contents in cocoa. The study shows that, apart from the known correlation of soil conditions with Cd accumulation in cacao seeds, changes in fertilization and plant composition may be promising measures to counteract Cd contamination in regions with high soil Cd content.
Mostrar más [+] Menos [-]Adsorption Behavior of Cobalt onto Saline Soil with/without a Biosurfactant: Kinetic and Isotherm Studies
2019
Narimannejad, S. | Zhang, B. | Lye, L.
Cobalt (Co) adsorption onto saline soil was investigated in this study. The effect of pH, interaction time, and initial concentration of Co on adsorption were evaluated empirically to screen the appropriate operating conditions. Three biosurfactant products (i.e., surfactin, trehalose lipids, rhamnolipid) each at two concentrations (1 and 2 critical micelle concentrations (CMCs)) were applied during Co adsorption. The adsorption kinetic models were explored and results indicated that the pseudo-second-order kinetic model fit the experimental data the best. Four isotherms, including Langmuir, Freundlich, Temkin, and Redlich-Peterson were used for regulating the Co adsorption with and without the addition of each biosurfactant. The research results show that Co has low mobility even with the existence of a biosurfactant. The findings help to better understand the adsorption behaviour of Co in saline soil so as to develop applicable remediation options.
Mostrar más [+] Menos [-]Photodegradation of 2,4-dichlorophenol and rhodamine B over n-type ZnO/p-type BiFeO3 heterojunctions: detailed reaction pathway and mechanism
2019
Humayun, Muhammad | Zheng, Zhiping | Fu, Qiuyun | Luo, Wei
The development of new technologies for efficient degradation of pollutant has been an increasing demand in the globe due to the serious environmental issues. Herein, we report n-type ZnO/p-type BiFeO₃ composites as highly efficient visible light nanophotocatalysts prepared via a wet chemical solution method. Based on the measurements of •OH-related fluorescence (FL) spectra, photoluminescence (PL) spectra, photoelectrochemical I–V curves, and electrochemical impedance spectra (EIS), it is demonstrated that the photo-induced charge carrier (electron-hole pairs) in the as-prepared n-type ZnO/p-type BiFeO₃ composites with proper amount of the coupled ZnO (10% by mass) exhibits high separation compared with the bare BiFeO₃ (BFO) nanoparticles. This is well responsible for the superior visible light photocatalytic performance of the composites for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) degradation. It is confirmed by means of scavenger test and liquid chromatography-tandem mass spectrometry (LC/MS) analysis of the intermediate products that •OH is the pre-dominant oxidant involved in the degradation of 2,4-DCP. A detailed reaction pathway for 2,4-dichlorophenol degradation over the amount-optimized ZnO/BFO composite is proposed mainly based on the LC/MS product ions. This work will provide a feasible route to design and develop BFO-based highly efficient visible light–active photocatalysts for environmental purification and could be extended to other visible light–active semiconductor materials.
Mostrar más [+] Menos [-]An assessment of energy efficiency based on environmental constraints and its influencing factors in China
2019
Chen, Yao | Xu, Jing-ting
The super-efficiency directional distance function (DDF) with data envelopment analysis (DEA) model (SEDDF-DEA) is more facilitative than to increase traditional method as a rise of energy efficiency in China, which is currently important energy development from Asia-pacific region countries. SEDDF-DEA is promoted as sustained total-factor energy efficiency (TFEE), value added outputs, and Malmquist-Luenberger productivity index (MLPI) to otherwise thorny environmental energy productivity problems with environmental constraint to concrete the means of regression model. This paper assesses the energy efficiency under environmental constraints using panel data covering the years of 2000–2015 in China. Considering the environmental constraints, the results showed that the average TFEE of the whole country followed an upward trend after 2006. The average MLPI score for the whole country increased by 10.57% during 2005–2010, which was mainly due to the progress made in developing and applying environmental technologies. The TFEE of the whole nation was promoted by the accumulation of capital stock, while it was suppressed by excessive production in secondary industries and foreign investment. The primary challenge for the northeast of China is to strengthen industrial transformation and upgrade traditional industries, as well as adjusting the economy and energy structure. The eastern and central regions of the country need to exploit clean- or low-energy industry to improve inefficiencies due to excessive consumption. The western region of China needs to implement renewable energy strategies to promote regional development.
Mostrar más [+] Menos [-]Effects of different scrap iron as anode in Fe-C micro-electrolysis system for textile wastewater degradation
2019
Sun, Zhenhua | Xu, Zhihua | Zhou, Yuwei | Zhang, Daofang | Chen, Weifang
The degradation of organic contaminants in actual textile wastewater was carried out by iron carbon (Fe-C) micro-electrolysis. Different Fe-C micro-electrolysis systems (SIPA and SISA) were established by using scrap iron particle (SIP) and scrap iron shaving (SIS) as anode materials. The optimal condition of both systems was obtained at the initial pH of 3.0, dosage of 30 g/L and Fe/C mass ratio of 1:1. Commercial spherical Fe-C micro-electrolysis material (SFC) was used for comparison under the same condition. The results indicated that total organic carbon (TOC) and chroma removal efficiencies of SIPA and SISA were superior to that of SFC. Total iron concentration in solution and XRD analysis of electrode materials revealed that the former showed relatively high iron corrosion intensity and the physicochemical properties of scrap iron indeed affected the treatment capability. The UV-vis and 3DEEM analysis suggested that the pollutants degradation was mainly attributed to the combination of reduction and oxidation. Furthermore, the potential degradation pathways of actual textile wastewater were illustrated through the GC-MS analysis. Massive dyes, aliphatic acids, and textile auxiliaries were effectively degraded, and the SIPA and SISA exhibited higher performance on the degradation of benzene ring and dechlorination than that by SFC. In addition, SIPA and SISA exhibited high stability and excellent reusability at low cost. Graphical abstract
Mostrar más [+] Menos [-]Vulnerability assessment of areas allocated for municipal solid waste disposal systems: a case study of sanitary landfill and incineration
2019
Ngamsang, Thittaya | Yuttitham, Monthira
This study was conducted to assess the vulnerability of areas allocated for sanitary landfill in Nakhon Ratchasima and for incineration in Phuket, Thailand, and to investigate the factors contributing to their vulnerability. Analysis was conducted to develop a vulnerability index using a composite index approach and the Intergovernmental Panel on Climate Change (IPCC) framework approach, while correlation and t tests were applied to identify the relationships and differences between the two systems. Additionally, vulnerability indices were developed using the IPCC vulnerability definition. The results suggested that the vulnerability of the areas allocated for sanitary landfill and incineration were not significantly different. The factor that had the greatest impact on the vulnerability of the sanitary landfill was nuisance, while sub-component correlation analysis revealed that cadmium in groundwater was significantly negatively correlated with vulnerability (r = − 0.958, p < 0.05). Furthermore, the factor that had the greatest effect on vulnerability from incineration was leachate. Similarly, correlation analysis suggested that the chemical oxygen demand in leachate and solid waste residues was significantly positively correlated with vulnerability (r = 0.981, 0.975 respectively, p < .05). It is hoped that these findings can be used to establish measures for preventing environmental problems, as well as to prioritize and identify issues that need to be resolved urgently, and to help policy makers select appropriate systems for different regions of Thailand.
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