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451.
Long-term (≥20 years) application of fertilizers and straw return enhances soil carbon storage: a meta-analysis 总被引:2,自引:0,他引:2
Yu’e Li Shengwei Shi Muhammad Ahmed Waqas Xiaoxia Zhou Jianling Li Yunfan Wan Xiaobo Qin Qingzhu Gao Shuo Liu Andreas Wilkes 《Mitigation and Adaptation Strategies for Global Change》2018,23(4):603-619
Increasing soil carbon (C) storage is crucial to addressing climate change and ensuring food security. The C sequestration potential of the world’s cropland soil is 0.4–0.8 Pg soil C year?1, which may be achieved through the adoption of recommended management practices (RMPs), including fertilizer management. This study aimed to quantitatively evaluate the influence of long-term application of different fertilizers and straw retention on soil organic carbon (SOC) storage, to compare the calculated response ratios with Intergovernmental Panel on Climate Change (IPCC)-recommended default relative stock change factors, and to propose recommendations for enhancing SOC sequestration. The meta-analysis indicated that the long-term application of chemical fertilizers (CF), organic fertilizers (OF), combined chemical and organic fertilizers (CFOF), and straw return (SR) significantly enhanced the SOC storage. Response ratios varied significantly (p < 0.05) across different fertilization measures and climatic zones, and was sensitive to the initial SOC content. The mean response ratio was 0.94 for no fertilizer (NF), 1.08 for CF, 1.48 for OF, 1.38 for CFOF, and 1.28 for SR. When IPCC default values for response ratios were applied, SOC storage with OF and CFOF treatments in warm temperate regions with a dry climate was underestimated by 26%, and in the cool temperate region with a moist climate was overestimated by 25% (p < 0.05). Analysis showed that sustained application of organic fertilizers and straw return could be a beneficial measures to mitigate climate change and ensure food security in China. Our findings highlight the importance of deriving SOC stock change factors for a detailed classification of cropland by fertilizer management, climate, and soil types in order to more accurately reflect the effects of policy measures. 相似文献
452.
Andreas Uihlein Witold-Roger Poganietz Liselotte Schebek 《Resources, Conservation and Recycling》2006,46(4):410-429
Today, global climate change is one of the most urgent environmental problems. The atmospheric concentration of carbon dioxide (CO2) has to be stabilised by significant reductions of CO2 emissions in the next decades to keep the expected temperature rise within tolerable borders. Efforts exceeding the implemented measures to reduce CO2 emissions in Germany are desirable. An important pre-condition for such measures is a scientific-based inventory of the sources, sinks, and use of carbon.In this paper, we present CarboMoG, i.e. Carbon Flow Model of Germany. CarboMoG is a carbon flow model covering carbon flows, carbon sources and sinks in Germany and the German anthroposphere, showing concurrent energy and non-energy use of carbon sources.The model consists of seven modules in German anthroposphere following the German classification of economic sectors. Carbon flows to and from atmosphere and lithosphere as well as imports and exports were included into the model. The model comprises roughly 220 material flows determined based on material flow procedures for the base year 2000.Main sources of carbon are fossil energy carriers from lithosphere and uptake of CO2 by crops (52% resp. 48% of all carbon sources). The model calculations show that import of energy carriers dominates total carbon import to Germany (82%). Total non-energy use of carbon in Germany is significantly higher than energy use (386 Mt C and 230 Mt C, resp.). Carbon throughput of Industry is greatest (about 224 Mt C input), followed by Energy (about 129 Mt C input). Agriculture and Forestry & Industry show the highest figure for non-energy use of carbon, energy use of carbon is largest in the Energy sector. Emissions of CO2 to atmosphere account for 94% of all carbon flows to sinks in Germany. Carbon accumulates in German anthroposphere 5 Mt C in 2000. 相似文献
453.
Remediation of heavy metal polluted sediment by suspension and solid-bed leaching: estimate of metal removal efficiency 总被引:2,自引:0,他引:2
Remediation of heavy metal polluted sediment by extracting the metals with sulfuric acid can be performed as follows: abiotic suspension leaching, microbial suspension leaching, abiotic solid-bed leaching, and microbial solid-bed leaching. Abiotic leaching means that the acid is directly added, while microbial leaching means that the acid is generated from sulfur by microbes (bioleaching). These four principles were compared to each other with special emphasis on the effectiveness of metal solubilization and metal removal by subsequent washing. Abiotic suspension leaching was fastest, but suspending the solids exhibits some disadvantages (low solid content, costly reactors, permanent input of energy, high water consumption, special equipment required for solid separation, large amounts of waste water, sediment properties hinder reuse), which prevent suspension leaching in practice. Abiotic solid-bed leaching implies the supply of acid by percolating water which proceeds slowly due to a limited bed permeability. Microbial solid-bed leaching means the generation of acid within the bed and has been proven to be the only principle applicable to practice. Metal removal from leached sediment requires washing with water. Washing of solid beds was much more effective than washing of suspended sediment. The kinetics of metal removal from solid beds 0.3, 0.6 or 1.2m in height were similar; when using a percolation flow of 20lm(-2)h(-1), the removal of 98% of the mobile metals lasted 57-61h and required 8.5, 4.2 or 2.3lkg(-1) water. This means, the higher the solid bed, the lower the sediment-mass-specific demand for time and water. 相似文献
454.
Characterisation of polymer fractions from waste electrical and electronic equipment (WEEE) and implications for waste management 总被引:2,自引:0,他引:2
There is an increasing interest in the end-of-life management of polymers present in waste electrical and electronic equipment (WEEE). This is mainly due to high recycling and recovery quotas set by the European WEEE directive, which can only be fulfilled by including the plastic fraction in recycling and recovery approaches. Previous studies identified a high material diversity and various contaminants in WEEE plastics, including heavy metals, polybrominated biphenyls (PBB), diphenyl ethers (PBDE), as well as polybrominated dibenzodioxins and dibenzofurans (PBDD/F). These substances are regulated by European directives that limit their levels in marketable products. Consequently, both material diversity and contaminants are strong arguments against material recycling and point to hazardous waste treatment. However, recent developments in the production of flame retardants and electrical and electronic goods aimed to reduce contaminants and material diversity. Thus, the present study summarises updated contaminant levels of plastic fractions of European WEEE, as well as data on materials in waste housing polymers. Material characterisation revealed housing fractions to be interesting sources for polymer recycling, which however has to implement potent material separation and/or bromine elimination techniques. With respect to contaminants, our data indicate an effective phase-out of PBB, but still high levels of PBDE and PBDD/F are found. Sources and implications for the material recycling and thermal recovery approaches are discussed in detail. 相似文献
455.
Schlummer M Mäurer A van Eldik R Quicker P Fischer W Faulstich M 《Environmental science and pollution research international》2007,14(6):414-420
GOAL, SCOPE AND BACKGROUND: Changes in German and European legislation shifted processing of polymer-rich shredding residues (SR) from landfill to thermal treatment. However, when waste of electric and electronic equipment (WEEE) is the source of SR, thermal treatment is complicated by halogens as well as the presence of polybrominated dioxins and furans (PBDD/F) and brominated flame retardants (BFR). Hence, WEEE requires high temperature incineration with sufficient residence times. Post-combustion synthesis of polyhalogenated dioxins and furans (PXDD/F) is dominant in the temperature range between 250-450 degrees C. Thus, a very rapid gas cooling from 450 degrees to 250 degrees C is important for proper raw gas treatment. The pebble heater technology developed by ATZ Entwicklungszentrum (Sulzbach-Rosenberg, Germany) might serve as an alternative to the state-of-the-art quench cooling. It is based on the application of a pebble bed of natural bulk material, which the exhaust gases flows through radially. It provides an excellent heat transfer and a temperature gradient in the range of 1,500-2,000 K/m. The paper presents data of a pilot application of the pebble heater technology for the treatment of raw gas derived from the incineration of polymeric materials from WEEE. METHODS: A liquid fuel was chosen in order to minimise technical modifications of the plant. It was analysed for halogens by x-ray fluorescence, for brominated flame retardants by HPLC-UV/MS and for PXDD/F by GC-HRMS. Combustion gases were rapidly cooled down to temperatures below 200 degrees C and emissions of PBDD/F and PCDD/ F were estimated without further off-gas treatment. PBDD/F emissions were computed as PCDD/F toxicity equivalents applying two different calculation approaches. RESULTS AND DISCUSSION: PCDD/F emissions accounted for 0.04 ng I-TEQ/Nm3 and are in compliance with European emission limits. Calculated PBDD/F toxicity equivalents exceeded the emission limit of 0.1 ng I-TEQ/Nm3 by factors of 75 and 208 depending on the calculation approach. A mass balance of PBDD/F and PCDD/F congeners revealed an efficient elimination of more than 95% in most cases. Lower reduction rates (76% for 2,3,7,8-TeBDF and 82% for 1,2,3,7,8-PeBDF) were attributed to incomplete combustion. An intended recovery of halogens by one-stage scrubbing downstream of the pebble heater was ineffective, recovering 28% of the applied chlorine and 9% of the bromine, only. CONCLUSIONS: Our pilot incineration test indicates that the pebble heater technology can effectively suppress a post-combustion synthesis of PCDD/F and PBDD/F, resulting in low PCDD/F emission levels without further off-gas treatment. The presented data state that WEEE is sensible to incomplete combustion, which will lead to increased PBDD/F emissions without increasing PCDD/F emission limits. This finding is especially relevant for small and low-technical incineration appliances, which have been reported to treat WEEE in developing countries and are considered to serve as a significant source of PXDD/F these days. RECOMMENDATIONS AND PERSPECTIVES: Monitoring of PCDD/F emissions only might considerably underestimate the total emission of dioxins and dioxin-like compounds. It is therefore an ineffective means for assessing resulting health risks, at least for those waste treatment plants which are considered to handle the increasing amounts of PBDD/ F-containing polymers from WEEE in future. Consequently, it is recommended to initiate a screening programme for PXDD/F emissions in large scale incineration facilities which are capable of treating WEEE shredder residues. 相似文献
456.
In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process monitoring revealed that prevailing climatic conditions in a subtropical location do not affect the high efficiency of this technology. However, the composition of the input material can be detrimental for production of high quality compost because of a lack of nitrate. 相似文献
457.
458.
Greis T Helmholz K Schöniger HM Haarstrick A 《Environmental monitoring and assessment》2012,184(6):3577-3591
In this study, a 3D urban groundwater model is presented which serves for calculation of multispecies contaminant transport
in the subsurface on the regional scale. The total model consists of two submodels, the groundwater flow and reactive transport
model, and is validated against field data. The model equations are solved applying finite element method. A sensitivity analysis
is carried out to perform parameter identification of flow, transport and reaction processes. Coming from the latter, stochastic
variation of flow, transport, and reaction input parameters and Monte Carlo simulation are used in calculating probabilities
of pollutant occurrence in the domain. These probabilities could be part of determining future spots of contamination and
their measure of damages. Application and validation is exemplarily shown for a contaminated site in Braunschweig (Germany),
where a vast plume of chlorinated ethenes pollutes the groundwater. With respect to field application, the methods used for
modelling reveal feasible and helpful tools to assess natural attenuation (MNA) and the risk that might be reduced by remediation
actions. 相似文献
459.
Breuer D Heckmann P Gusbeth K Schwab G Blaskowitz M Moritz A 《Journal of environmental monitoring : JEM》2012,14(2):440-445
Until 2009, the limit values for airborne sulfuric acid in Europe were based on the inhalable particle fraction (e.g. MAK (Maximum allowed concentration at workplace) value 0.1 mg m(-3) as the inhalable fraction). With the publication of the Commission Directive 2009/161/EU, an Indicative Occupational Exposure Limit Value (IOELV) of 0.05 mg m(-3) for sulfuric acid aerosols was based for the first time on the thoracic particle fraction. To permit a comparison of the measured values for the inhalable fraction with those of the thoracic fraction and to quantify the thoracic fraction, a cyclone was fabricated out of sulfuric-acid-resistant stainless steel that achieves suitable collection characteristics (PM(10)) at a flow rate of 5.34 L min(-1). 49 measurements were carried out in parallel in 21 companies. At concentrations well below the IOELV, there is little difference between the thoracic and inhalable particle concentrations. At higher concentrations (>0.1 mg m(-3) inhalable aerosol), larger droplets have a marked effect on the measured values and the thoracic fraction accounts for only 32.1 ± 12.5% of the inhalable fraction. The EU's IOELV and the proposal of the MAK Commission therefore provide a comparable level of protection. In the transposition of the IOELV into national law, an air limit of 0.1 mg m(-3) could therefore be implemented for the inhalable fraction. 相似文献
460.
Andreas Kannen 《Regional Environmental Change》2014,14(6):2139-2150
Today, increasing use intensity and establishment of new sea uses such as offshore wind farming can be observed in coastal and marine waters. This development also increases the pressure on coastal and marine ecosystems. The exclusive economic zone of the German North Sea can serve as an example for this development, in particular illustrating the need to combine multiple uses and societal demands within a given sea area. In order to deal with the resulting conflicts and cumulative impacts, new planning tools and integrated approaches to planning and management are developing. While the sea becomes a contested but at the same time politically recognised area, also conflicts rooted in different perceptions, values and attitudes of coastal people can be observed. In order to deal with the current challenges in marine areas, marine spatial planning and similar tools for integrated planning need to be developed in the form of communication processes, which link diverse sets of information and span a dialogue between groups of society and across spatial scales including the transnational dimension. 相似文献