Decomposition of CCl4 and CHCl3 on gliding arc plasma

Introduction C hlorinated volatile organic com pounds(C V O C s) w ere released to the atm osphere as flue gases from various industrial processes. C hlorinated hydrocar- bons have been w idely accepted as solvents and chem ical interm ediates in the m an…     

Planning for Climate Change: Identifying Minimum-Dispersal Corridors for the Cape Proteaceae

Abstract:  Climate change poses a challenge to the conventional approach to biodiversity conservation, which relies on fixed protected areas, because the changing climate is expected to shift the distribution of suitable areas for many species. Some species will persist only if they can colonize new areas, although in some cases their dispersal abilities may be very limited. To address this problem we devised a quantitative method for identifying multiple corridors of connectivity through shifting habitat suitabilities that seeks to minimize dispersal demands first and then the area of land required. We applied the method to Proteaceae mapped on a 1-minute grid for the western part of the Cape Floristic Region of South Africa, to supplement the existing protected areas, using Worldmap software. Our goal was to represent each species in at least 35 grid cells (approximately 100 km²) at all times between 2000 and 2050 despite climate change. Although it was possible to achieve the goal at reasonable cost, caution will be needed in applying our method to reserves or other conservation investments until there is further information to support or refine the climate-change models and the species' habitat-suitability and dispersal models.     

Long-Term Avifaunal Impoverishment in an Isolated Tropical Woodlot

Abstract:  Long-term (>50 years) extinction patterns and processes in isolated tropical forest patches are poorly understood. Considering that forest fragments are rapidly becoming the common feature of most tropical landscapes, data on the long-term conservation value of such fragments are urgently needed. We report on avifaunal turnover in a tropical woodlot (Bogor Botanical Gardens; 86 ha; 54% native and 46% introduced plants; mean 83,649 visitors/month) that has been surveyed several times before and after its isolation in 1936. By 2004 the original avifaunal richness of this woodlot declined by 59% (97 to 40 species) and its forest-dependent avifauna declined by 60% (30 to 12 species). Large-bodied birds were particularly prone to extinction before 1987, but following this time none of the species traits we studied could be considered predictive of extinction proneness. All seven forest-dependent bird species that attempted to colonize this woodlot by 1987 perished thereafter. Our results show that area reduction, isolation, intense human use, and perverse management (e.g., understory removal) of this patch have probably negatively affected the long-term sustainability of its forest avifauna.     

生物炭对土壤氮素淋失的抑制作用

淋洗作用是土壤氮肥损失途径之一,也是环境水体氮素污染的重要途径。研发降低土壤氮素淋失的技术途径不仅有助于提高氮肥利用率和降低化肥的施用量,而且有助于防治水体污染和改善生态环境。本文通过淋滤实验研究了生物炭对我国两种重要土壤类型黒钙土和紫色土氮素淋失的影响。由玉米秸秆制成的生物炭按10 t/ha,50 t/ha,100 t/ha的比例施用于土壤,同时模拟田间尿素施用量240 kg.N/ha并用相当于每天10 mm的降水量用去离子水淋洗土壤。对淋滤液氮素组成和含量分析结果显示,在不施用生物炭的条件下,黒钙土和紫色土总氮的淋失量分别占土壤(土壤+尿素)总氮含量的7.5%和9.0%,氮素的淋失主要发生在前130 mm降水过程中,其淋失量占全部淋失量的96%。在淋失的成分中,除硝态氮外,有机氮也是重要的组成物质,二者均占淋失总氮量的48%。生物炭的施用可以大幅度地降低氮素的淋失作用。50 t/ha和100t/ha的生物炭施用量降低黑钙土氮素淋失分别为29%和74%,减少紫色土氮素淋失分别达41%和78%。但10 t/ha的生物炭施用量却增加黒钙土和紫色土氮素淋失量分别达到22%和2%。这表明较低的生物炭施用量会促进氮素的淋失。生物炭对有机氮淋失的抑制作用大于硝态氮。100 t/ha的生物炭施用量对有机氮和硝态氮淋失的降低率分别为88%和62%左右,因土壤类型不同而有所差异。上述研究结果为寻求防治土壤氮素淋失的技术方法提供了理论依据。     

生物炭对水体中铵氮的吸附特征及其动力学研究

以生物炭作为吸附剂,通过静态实验研究了生物炭对水体中铵氮的吸附特性,并从动力学角度探讨了其吸附机理。结果表明,生物炭对铵氮的吸附在60min内基本达到吸附平衡,其吸附量随着水溶液中铵氮的增加而增加,Langmuir方程能够更好的描述铵氮在生物炭上的等温吸附行为,最大吸附量为l.24mg／g,铵氮在生物炭上的吸附动力学数...     

Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil

Municipal solid waste landfills emit nitrous oxide （N2O） gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites. The N2O emission rates from all test sites were considerably lower than those reported in the published reports. Specifically, the N2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil. The effects of leachate recirculation and irrigation were minimal. Properly chosen cover soils applied to the landfills reduced N2O flux.     

Naphthalene emissions from moth repellents or toilet deodorant blocks determined using head-space and small-chamber tests

The present study investigated the emissions of naphthalene and other compounds from several different moth repellents(MRs) and one toilet deodorant block(TDB)currently sold in Korea,using a headspace analysis.The emission factors and emission rates of naphthalene were studied using a small-scale environmental chamber.Paper-type products emitted a higher concentration of the total volatile organic compounds(VOCs)(normalized to the weight of test piece)than ball-type products,which in turn emitted higher ...     

相关分析和主成份分析在有机酸来源分析中的应用

源解析是大气中低分子有机酸研究的重要内容。收集了贵阳市和尚重镇2006年5月至2007年4月降水样品,测定其中有机酸和主要的无机离子。结果表明,大气降水有机酸存在显著相关关系,说明两地区均存在有机酸的共同来源。运用不同来源示踪剂发现,尚重镇低分子有机酸来源比较单一,主要是受植物或土壤的直接和间接释放作用的影响;贵阳市低分子有机酸的来源相对复杂,尤其是人为活动和大气光化学反应都可能是大气有机酸的重要来源。主成分分析把贵阳市和尚重镇大气降水中主要离子大致分为3类,尚重镇SO42-、NO3-、HCOOH、CH3COOH和(COOH)2是第一主成份,反映了农业活动、土壤释放和生物质燃烧可能是这类污染物的重要来源,贵阳市降水中CH3COOH、HCOOH和(COOH)2具有较高的因子负荷,为第三主成份占方差总和的19.68%。     

Morphological and semi-quantitative characteristics of diesel soot agglomerates emitted from commercial vehicles and a dynamometer

Diesel soot aggregates emitted from a model dynamometer and 11 on-road vehicles were segregated by a micro-orifice uniform deposit impactor (MOUDI). The elemental contents and morphological parameters of the aggregates were then examined by scanning electron microscopy coupled with an energy dispersive spectrometer (SEM-EDS), and combined with a fractional Brownian motion (fBm) processor. Two mode-size distributions of aggregates collected from diesel vehicles were confirmed. Mean mass concentration of 339 mg/m3 (dC/dlogdp) existed in the dominant mode (180–320 nm). A relatively high proportion of these aggregates appeared in PM1, accentuating the relevance regarding adverse health e ects. Furthermore, the fBm processor directly parameterized the SEM images of fractal like aggregates and successfully quantified surface texture to extract Hurst coe cients (H) of the aggregates. For aggregates from vehicles equipped with a universal cylinder number, the H value was independent of engine operational conditions. A small H value existed in emitted aggregates from vehicles with a large number of cylinders. This study found that aggregate fractal dimension related to H was in the range of 1.641–1.775, which is in agreement with values reported by previous TEM-based experiments. According to EDS analysis, carbon content ranged in a high level of 30%–50% by weight for diesel soot aggregates. The presence of Na and Mg elements in these sampled aggregates indicated the likelihood that some engine enhancers composed of biofuel or surfactants were commonly used in on-road vehicles in Taiwan. In particular, the morphological H combined with carbon content detection can be useful for characterizing chain-like or cluster diesel soot aggregates in the atmosphere.     

LCA法在韩国环境标志产品评价中的应用研究

中国在大力发展和推广环境标志产品的同时,对环境标志产品的系统评价工作却显得薄弱,仍主要停留在能源消耗、污染物排放、废弃回收等单一因素或简单组合方式,缺乏客观性、全面性。因此借鉴国外有关先进经验,尽快建立系统的环境标志产品评价体系是很有必要的。韩国环境标志产品LCA评价的最大优点是将复杂、专业的数据转变为易于国民理解的简单形式,而有利于环境标志产品的宣传与发展。文章以LCA法在评价韩国环境标志产品中的应用为实例,系统说明其评价过程,并探讨其优势和不足,为中国相关工作的开展提供可借鉴的经验。