Effectiveness of non-CO2 greenhouse gas emission reduction technologies

Non-CO₂ greenhouse gases, such as methane and nitrous oxide, can make a relevant contribution to the enhanced greenhouse effect, and hence emission reduction is desirable. In emission reduction inventories, both the magnitude of the emission reduction as well as the specific emission reduction costs should be determined. The current knowledge of the potential for and costs of reducing these emissions is still limited. Taking this into account, the following results can be obtained. Methane emissions can be considerably reduced from underground coal mining, oil production, natural gas operations, landfilling of waste, and wastewater treatment. Also emissions from enteric fermentation and animal manure can be reduced substantially. The total technical potential for methane emission reduction (given the present activity level) is estimated to be about one third. The economic potential, having net negative emission reduction costs, is estimated to be about half of this value. These reductions can be attained over a period of 10 – 20 years. The technical potential for the reduction of nitrous oxide emissions is currently estimated to be less than 10% Apart from the possibility of implementing existing techniques, there seems to be considerable room for developing techniques for more far-reaching emission reductions both for methane and nitrous oxide.     

LCA-IWM: a decision support tool for sustainability assessment of waste management systems

The paper outlines the most significant result of the project 'The use of life cycle assessment tools for the development of integrated waste management strategies for cities and regions with rapid growing economies', which was the development of two decision-support tools: a municipal waste prognostic tool and a waste management system assessment tool. The article focuses on the assessment tool, which supports the adequate decision making in the planning of urban waste management systems by allowing the creation and comparison of different scenarios, considering three basic subsystems: (i) temporary storage; (ii) collection and transport and (iii) treatment, disposal and recycling. The design and analysis options, as well as the assumptions made for each subsystem, are shortly introduced, providing an overview of the applied methodologies and technologies. The sustainability assessment methodology used in the project to support the selection of the most adequate scenario is presented with a brief explanation of the procedures, criteria and indicators applied on the evaluation of each of the three sustainability pillars.     

Success of collaboration for sustainable agriculture: a case study meta-analysis

Environment, Development and Sustainability - More and better collaboration between farmers and other stakeholders has repeatedly been identified as a key strategy for sustainable agriculture....     

Slow desorption of PCBs and chlorobenzenes from soils and sediments: relations with sorbent and sorbate characteristics

The kinetics of slow desorption were studied for four soils and four sediments with widely varying characteristics [organic carbon (OC) content 0.5-50%, organic matter (OM) aromatic content (7-37%)] for three chlorobenzenes and five polychlorinated biphenyls (PCBs). Slowly and very slowly desorbing fractions ranged from 1 to 50% (slow) and 3 to 40% (very slow) of the total amount sorbed, and were observed for all compounds and all soils and sediments. In spite of the wide variations in sorbate K(OW) (factor 1000) and sorbent characteristics, the rate constants of slow (k(slow), around 10(-3) h(-1)) and very slow (k(very slow), 10(-5)-10(-4) h(-1)) desorption appeared to be rather constant among the sorbates and sorbents (both within a factor of 5). There was a good correlation (r(2) above 0.9) between the distribution over the slow, very slow and rapid sediment fractions and log K(OC), indicating that sorbate hydrophobicity may be important for this distribution. No correlation could be found between sorbent characteristics [OC, N, and O in the organic matter, polarity index C/(N+O), OC aromaticity as determined by CP-MAS (13)C-NMR] and slow desorption parameters (slowly/very slowly desorbing fractions+corresponding rate constants). The absence of (1) a correlation between k(slow) and k(very slow), respectively, and OC content, and (2) the narrow range of k(slow) and k(very slow) values, indicates that intra-OM diffusion is not the mechanism of slow or very slow desorption, because on the basis of this mechanism it would be expected that increasing OC content would lead to longer diffusion pathlengths and, consequently, to smaller rate constants. In addition, it was tested whether differential scanning calorimetry would reveal a glass transition in the soils/sediments. In spite of the sensitivity of the equipment used (changes in heat flow in the micro-Watt range were measurable), a glass transition was not observed. This means that activation enthalpies of slow desorption can be calculated from desorption measurements at various temperatures. In the present study these values ranged from 60 to 100 kJ/mol among the various soils and sediments studied.     

Opportunities for a probabilistic risk assessment of chemicals in the European Union

In risk assessment of new and existing substances, it is current practice to characterise risk using a deterministic quotient of the exposure concentration, or the dose, and a no-effect level. A sense of uncertainty is tackled by introducing worst-case assumptions in the methodology. Since this procedure leads to an assessment with an unknown degree of conservatism, it is advisable to deal quantitatively with uncertainties. This paper discusses the advantages and possibilities of a probabilistic risk assessment framework, illustrated with an example calculation. Furthermore, representatives of EU Member States and the chemical industry were interviewed to find out their views on applying uncertainty analysis to risk assessment of industrial chemicals.     

Estimation of no effect concentrations from exposure experiments when values scatter among individuals

The parameters that are most commonly used in risk assessment, LC_x values or no observed effect concentrations, both have serious drawbacks. As an alternative, No effect concentrations (NEC) as a parameter in a process-based model, offer great potential in risk assessment.     

微囊藻毒素-LR多克隆抗体的制备

通过对新西兰大白兔免疫自制的微囊藻毒素-LR(Microcystin-LR,MC-LR)完全抗原BSA-MC-LR,获得了质量较好的抗MC-LR的多克隆抗体,间接ELISA表明抗体的效价能达到1.5×10⁵;固定包被抗原OVA-MC-LR,采用间接竞争ELISA测定水体中的微囊藻毒素,标准曲线表明对水样中MC-LR的检测下限为10ng/L,线性区间为30ng/L·3μg/L,能满足对饮用水和地表水中MC-LR的检测要求.     

Improving the aeration of critical fine-grained landfill top cover material by vegetation to increase the microbial methane oxidation efficiency

The natural methane oxidation potential of methanotrophic bacteria in landfill top covers is a sustainable and inexpensive method to reduce methane emissions to the atmosphere. Basically, the activity of methanotrophic bacteria is limited by the availability of oxygen in the soil. A column study was carried out to determine whether and to what extent vegetation can improve soil aeration and maintain the methane oxidation process. Tested soils were clayey silt and mature compost. The first soil is critical in light of surface crusting due to vertical erosion of an integral part of fine-grained material, blocking pores required for the gas exchange. The second soil, mature compost, is known for its good methane oxidation characteristics, due to high air-filled porosity, favorable water retention capacity and high nutrient supply. The assortment of plants consisted of a grass mixture, Canadian goldenrod and a mixture of leguminous plants. The compost offered an excellent methane oxidation potential of 100% up to a CH₄-input of 5.6 l CH₄ m⁻² h⁻¹. Whereas the oxidation potential was strongly diminished in the bare control column filled with clayey silt even at low CH₄-loads. By contrast the planted clayey silt showed an increased methane oxidation potential compared to the bare column. The spreading root system forms secondary macro-pores, and hence amplifies the air diffusivity and sustain the oxygen supply to the methanotrophic bacteria. Water is produced during methane oxidation, causing leachate. Vegetation reduces the leachate by evapotranspiration. Furthermore, leguminous plants support the enrichment of soil with nitrogen compounds and thus improving the methane oxidation process. In conclusion, vegetation is relevant for the increase of oxygen diffusion into the soil and subsequently enhances effective methane oxidation in landfill cover soils.