生物质炭的性质及其对土壤环境功能影响的研究进展

在厌氧或者绝氧的条件下对生物质进行热解,可产生含碳丰富的固体物质,称为生物质炭。由于生物质炭在农业和环境中的巨大应用前景和对土壤碳的增汇减排作用,近期成为土壤学和环境科学的研究热点。综述了生物质炭的一些基本性质及其对土壤环境功能的影响,分析了该领域未来的发展趋势。国内外的研究表明：生物质炭含有大量植物所需的营养元素,可以促进土壤养分的循环和植物的生长;生物质炭一般呈碱性,施用生物质炭可以降低土壤的酸度和有毒元素如铝和重金属对植物的毒性;生物质炭表面含有丰富的-COOH、-COH和-OH等含氧官能团,它们产生的表面负电荷使生物质炭具有较高的阳离子交换量（CEC）,施用后可以提高土壤的CEC;生物质炭对农药等有机污染物和重金属等有很强的吸附能力,可用于污染土壤的修复;生物质炭具有高度的孔隙结构,可以增加土壤的空隙度和保水能力,降低土壤容重,有利植物根系生长;生物质炭是一种含碳的聚合物,主要由单环和多环的芳香族化合物组成,这种结构特点决定了生物质炭具有较高的化学和生物学稳定性,较强的抵抗微生物分解的能力,增强了土壤的固碳作用,减少碳向大气的再释放。该文可为从事农业废弃物的资源化利用、固碳减排、污染土壤修复和土壤改良与管理等领域的科研人员提供参考。     

中国农业领域温室气体主要减排措施研究分析

气候变暖已成不争事实,主要是由于人为温室气体(GHG)排放增加所致,为减缓气候变暖趋势,各领域迫切需要采取减排措施;农业是一个重要的GHG排放源,农业领域采取减排措施对于减少我国GHG排放、保护农村生态环境有重要意义。文章在大量阅读前人研究结果的基础上,总结我国农业领域主要的减排管理措施,主要从农业活动、农村生活和生物质能源利用三方面进行阐述,并简要分析各措施的减排效果和存在问题。分析发现,农业活动的水肥管理是农田温室气体减排的研究热点,但由于地域和管理流程上的差异,对措施的减排效果尚存在争议;农村生活中存在巨大的减排潜力,采取恰当的减排措施不但可以减少GHG排放,还可以改善农村生态状况和环境卫生条件;农村生物质能源有很大发展潜力,合理开发利用,可以有效替代化石能源消耗,缓解能源危机,减少GHG排放,保护生态环境。总之,在农业领域采取积极的减排措施,有助于国家效应对气候变化,降低农业源污染和GHG排放,减轻环境压力,转换农业发展模式,加速农业现代化,促进农业生产的可持续发展和社会主义新农村建设。     

New Metal Emission Patterns in Road Traffic Environments

The increased awareness of traffic as a major diffuse metal emission source emphasizes the need for more detailed information on the various traffic-related sources and how and where the metals are dispersed. In this study, metal emission patterns in the road traffic environment were examined from the perspective of different surrounding factors, e.g. the importance of intersections, deceleration, vehicle speed and traffic density. A total of 148 topsoil samples from 18 south Swedish roads were analysed (using GFAAS) for traffic-emitted metals, i.e. Cd, Cr, Cu, Ni, Pb, Sb and Zn. The roadside topsoil metal concentrations were used to examine correlations between metals and surrounding factors. The studied metals were divided into three groups corresponding to different emission sources: metals from decelerating activities (Cu, Sb and Zn), metals as historical residues from the combustion of petrol (Pb and Cd), and non-source-specific metals (Cr and Ni). It was found that Cu and Sb, despite their rather short history as traffic-emitted metals, have increased more than eightfold in roadside soils compared to background levels. The major source of road traffic related Cu and Sb is brake linings. The significant increase of Cu and Sb in roadside topsoil stresses the need for metal transport studies as well as effect studies of these metals. Metals emitted due to decelerating activities were not correlated to elevated concentrations near road junctions. Emission patterns of traffic-related metals alongside roads are crucial in order to be able to evaluate the optimal localization of storm water treatment ponds.     

Evaluation of Carbon Uptake and Emissions by Forests in Korea During the Last Thirty Years (1973–2002)

The contribution of Korean forests to carbon sequestration for anthropogenic carbon emissions was evaluated. In addition, monitoring of carbon species released from forest fires was conducted. Despite a high carbon uptake by Korean forests, a tremendous increase in fossil fuel burning resulted in a small contribution by forests to carbon removal. The removal efficiency had a 5–31% range with an average of 12% during the period 1973–2002. In 2000, the amount of carbon released from burned trees corresponded to 1.6% of carbon uptake by forests. The distribution of surface CO concentration (ppb) derived from MOPITT (Measurement of Pollution in the Troposphere) showed high CO levels over the East/Japan Sea on April 10, 2000 when the largest forest fires occurred along the east coast of Korea. Trajectory analysis and ground CO measurements also indicated that CO levels over the East/Japan Sea were influenced by forest fires. This study suggests that continuous monitoring of carbon emissions from forest fires is needed for a more reliable estimate of carbon flux in the environment.     

Multipoint source method in air pollution modelling of cold start emission

The paper presents a new method of air pollution modelling on a micro scale. For estimation of concentration of car exhaust pollutants, each car is treated as an instantaneous moving emission source. This approach enables us to model time and spatial changes of emission, especially during cold and cool start of an engine. These stages of engine work are a source of significant pollution concentration in urban areas. In this work, two models are proposed: one for the estimation of emission after cold start of the engine and another for the prediction of pollutant concentration. The first model (defined for individual exhaust gas pollutants) enables us to calculate the emission as a function of time after the cold or cool start, ambient temperature and average speed of motion. This model uses the HBEFA database. The second mathematical model is developed in order to calculate the pollutant dispersion and concentrations. The finite volume method is applied to discretise the set of partial differential equations describing wind flow and pollutant dispersion in the domain considered. Models presented in this paper can be called short-term models on a small spatial scale. The results of numerical simulation of pollutant emission and dispersion are also presented.     

环境空气中VOC_S在线监测法与SUMMA罐采样气相色谱-质谱法比对研究

定性比较了环境空气VOCs在线监测法和SUMMA罐采样GC-MS法的基本原理、检测化合物种类和适用范围,并对标样实验、日均浓度、小时浓度从统计学角度进行了定量比对.研究表明,VOCs在线监测法监测结果与实验室方法有较好可比性,可用于相关领域VOCs的连续监控.     

石化行业的VOCs排放控制管理

概述了我国挥发性有机化合物（VOCs）的排放情况。介绍了国内外VOCs的管理现状。分析了国内石化行业VOCs排放控制管理中存在的主要问题以及污染物排放过程的类别。提出了明确定义、制定相关标准、完善分类管理体系、研究最佳的可行性控制技术等加强VOCs排放控制管理的对策和建议。     

Using multivariate regression modeling for sampling and predicting chemical characteristics of mixed waste in old landfills

Municipal solid waste landfills pose a threat on environment and human health, especially old landfills which lack facilities for collection and treatment of landfill gas and leachate. Consequently, missing information about emission flows prevent site-specific environmental risk assessments. To overcome this gap, the combination of waste sampling and analysis with statistical modeling is one option for estimating present and future emission potentials. Optimizing the tradeoff between investigation costs and reliable results requires knowledge about both: the number of samples to be taken and variables to be analyzed.This article aims to identify the optimized number of waste samples and variables in order to predict a larger set of variables. Therefore, we introduce a multivariate linear regression model and tested the applicability by usage of two case studies. Landfill A was used to set up and calibrate the model based on 50 waste samples and twelve variables. The calibrated model was applied to Landfill B including 36 waste samples and twelve variables with four predictor variables.The case study results are twofold: first, the reliable and accurate prediction of the twelve variables can be achieved with the knowledge of four predictor variables (Loi, EC, pH and Cl). For the second Landfill B, only ten full measurements would be needed for a reliable prediction of most response variables. The four predictor variables would exhibit comparably low analytical costs in comparison to the full set of measurements. This cost reduction could be used to increase the number of samples yielding an improved understanding of the spatial waste heterogeneity in landfills.Concluding, the future application of the developed model potentially improves the reliability of predicted emission potentials. The model could become a standard screening tool for old landfills if its applicability and reliability would be tested in additional case studies.     

不同小叶章湿地H2S和COS的排放通量研究

利用静态箱/气相色谱法,观测了小叶章沼泽化草甸和小叶章典型草甸两种湿地类型中H2S和COS在生长季(5-9月)的释放动态,结果表明:在两种小叶章湿地中,H2S和COS的排放通量均具有明显的季节和日变化规律.在小叶章沼泽化草甸中H2S和COS的平均释放通量分别为0.34μg·m-2·h-1和-0.29μg·m-2·h-1;小叶章典型草甸H2S和COS的平均释放通量分别为0.14μg·m-2·h-1和-0.20μg·m-2·h-1;小叶章沼泽化草甸H2S和COS的平均释放通量均高于小叶章典型草甸.在生长季两种小叶章湿地均能向大气释放H2S,对COS则表现为从大气中吸收.小叶章的生长过程对H2S和COS的排放影响显著,在小叶章生长旺盛期,H2S出现排放峰值,COS出现吸收高峰.     

植物对沼泽湿地生态系统N2O排放的影响

利用静态暗箱/气相色谱法连续3个生长季(2003-2005年)对三江平原小叶章草甸和毛果苔草沼泽N2O排放通量进行野外对比观测试验.结果表明,植物不同生长阶段对湿地生态系统N2O排放通量的影响不尽相同.植物的参与促进了湿地生态系统N2O的排放,2003-2005年生长季小叶章草甸土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.58倍、2.09倍和2.34倍,同期毛果苔草沼泽土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.86倍、1.50倍和1.33倍.3个生长季小叶章草甸N2O排放通量均大于毛果苔草沼泽,这主要是由土壤理化性质的空间变异性以及水文情况的差异造成的.