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91.
利用SPAMS 0515于2015年1月在盘锦市兴隆台空气质量自动监测点位采集PM_(2.5)样品,并分析其污染特征和来源。研究结果表明,盘锦市冬季PM_(2.5)的颗粒类型主要以OC颗粒、富钾颗粒、EC颗粒组成。其中,OC颗粒占比最高,为52.5%;PM_(2.5)污染的主要贡献源为燃煤、生物质燃烧、机动车尾气排放,占比分别为33.2%、25.7%、17.5%,特别是在PM_(2.5)质量浓度较高时段,燃煤和机动车尾气排放对污染的贡献较大。 相似文献
92.
综合传统重量法与冷凝法测定废气含湿量的特点,建立冷凝-吸附法测定固定源废气含湿量,有效解决重量法与冷凝法不适用于高温、高湿条件下的测定问题。通过优化测定条件,使冷凝-吸附法测定3台不同类型固定源废气结果的RSD为1.5%~4.7%,方法再现性试验结果的RSD为4.5%。用该方法与重量法同时测定油田注汽湿蒸汽发生器及普通流化床锅炉废气含湿量,结果表明冷凝-吸附法具备更强的适用性。 相似文献
93.
大气固定污染源低浓度颗粒物采样及分析技术研究进展 总被引:4,自引:0,他引:4
简述了我国现阶段大气固定污染源颗粒物监测中遇到的问题及低浓度颗粒物采样与分析技术研究的必要性,归纳了国外低浓度颗粒物采样分析技术要点,包括大体积采样、滤筒上游采样设备堆积颗粒物的回收、有效称重步骤的确立等,并对我国开展低浓度颗粒物采样及分析技术研究提出了相关建议. 相似文献
94.
海门市长江水厂饮用水源地富营养化调查及污染防治对策研究 总被引:1,自引:0,他引:1
采用综合营养状态指数法对2008年至2011年海门市长江水厂饮用水源地水质状况进行评价,结果表明,该水源地已呈现出富营养化的发展趋势。结合饮用水源地现状,必须采取控制外源和内源的排放、恢复生态系统等措施,遏止水体富营养化,确保人民群众的饮用水源安全。 相似文献
95.
以多年来中国各行业突发环境事故统计数据为基础,选取了对于企业突发环境事件有重大影响的7个因子以及17个指标,采用指标因子分析法对其进行定量,应用层次分析法确定各因子的权重,从而确定企业环境风险水平值。基于"危险物质水平—企业环境风险水平—周边环境受体状况"体系,构建了环境风险源分级矩阵,形成了包括"环境风险源初筛","环境风险源分级"的两步工业园区环境风险源识别与分级方法。该方法提出的工业园区环境风险源识别与分级体系具有科学性和可行性,能为工业园区环境风险管理提供依据。 相似文献
96.
Abstract: Conservation and restoration goals are often defined by historical baseline conditions that occurred prior to a particular period of human disturbance, such as European settlement in North America. Nevertheless, if ecosystems were heavily influenced by native peoples prior to European settlement, conservation efforts may require active management rather than simple removal of or reductions in recent forms of disturbance. We used pre‐European settlement land survey records (1859–1874) and contemporary vegetation surveys to assess changes over the past 150 years in tree species and habitat composition, forest density, and tree size structure on southern Vancouver Island and Saltspring Island, British Columbia, Canada. Several lines of evidence support the hypothesis that frequent historical burning by native peoples, and subsequent fire suppression, have played dominant roles in shaping this landscape. First, the relative frequency of fire‐sensitive species (e.g., cedar [Thuja plicata]) has increased, whereas fire‐tolerant species (e.g., Douglas‐fir [Pseudotsuga menziesii]) have decreased. Tree density has increased 2‐fold, and the proportion of the landscape in forest has greatly increased at the expense of open habitats (plains, savannas), which today contain most of the region's threatened species. Finally, the frequency distribution of tree size has shifted from unimodal to monotonically decreasing, which suggests removal of an important barrier to tree recruitment. In addition, although most of the open habitats are associated with Garry oak (Quercus garryana) at present, most of the open habitats prior to European settlement were associated with Douglas‐fir, which suggests that the current focus on Garry oak as a flagship for the many rare species in savannas may be misguided. Overall, our results indicate that the maintenance and restoration of open habitats will require active management and that historical records can provide critical guidance to such efforts. 相似文献
97.
MATTHEW E. WOLAK GEORGE W. GILCHRIST VICTORIA A. RUZICKA DANIEL M. NALLY RANDOLPH M. CHAMBERS 《Conservation biology》2010,24(5):1268-1277
Abstract: Juvenile growth rate and adult body size are important components of life‐history strategies because of their direct impact on fitness. The diamondback terrapin (Malaclemys terrapin) is a sexually dimorphic, long‐lived turtle inhabiting brackish waters throughout the Atlantic and Gulf coasts of the United States. In parts of its range, terrapins face anthropogenically imposed mortality: juveniles of both sexes inadvertently enter commercial crab traps and drown. For adult females, the carapace eventually grows large enough that they cannot enter traps, whereas males almost never reach that critical size. We compared age structure, carapace dimensions, growth curves, and indices of sexual dimorphism for a Chesapeake Bay population of terrapins (where mortality of turtles is high due to crab traps) with contemporary terrapins from Long Island Sound and museum specimens from Chesapeake Bay (neither group subject to commercial crab traps). We also calculated the allochronic and synchronic rates of evolutionary change (haldanes) for males and females to measure the rate of trait change in a population or between populations, respectively. We found a dramatic shift to a younger male age structure, a decrease in the length of time to terminal female carapace size, a 15% increase in female carapace width, and an increase in sexual dimorphism in Chesapeake Bay. In a new twist, our results implicate a fishery in the selective increase in size of a reptilian bycatch species. These sex‐specific changes in life history and demography have implications for population viability that need to be considered when addressing conservation of this threatened turtle. 相似文献
98.
Marc O. Ribaudo Jessica Gottlieb 《Journal of the American Water Resources Association》2011,47(1):5-14
Ribaudo, Marc O. and Jessica Gottlieb, 2011. Point‐Nonpoint Trading – Can It Work? Journal of the American Water Resources Association (JAWRA) 47(1):5‐14. DOI: 10.1111/j.1752‐1688.2010.00454.x Abstract: Water quality trading between point and nonpoint sources is of great interest as an alternative to strict command and control regulations on point sources for achieving water quality goals. The expectation is that trading will reduce the costs of water quality protection, and may speed compliance. The United States Environmental Protection Agency has issued guidance to the States on developing point‐nonpoint trading programs, and United States Department of Agriculture is encouraging farmer participation. However, existing point‐nonpoint trading programs have resulted in very few trades. Supply side and demand side impediments seem to be preventing trades from occurring in most trading programs. These include uncertainty over the number of discharge allowances different management practices can produce, high transactions costs of identifying trading partners, baseline requirements that eliminate low‐cost credits, the reluctance of point sources to trade with unfamiliar agents, and the perception of some farmers that entering contracts with regulated point sources leads to greater scrutiny and potential future regulation. Many of these problems can be addressed through research and program design. 相似文献
99.
Abstract: We examined how differences in local forest‐management institutions relate to disparate anthropogenic forest disturbance and forest conditions among three neighboring montane forests in Tanzania under centralized, comanaged, or communal management. Institutional differences have been shaped by decentralization reforms. We conducted semistructured interviews with members of forest management committees, local government, and village households and measured anthropogenic disturbance, tree structure, and species composition in forest plots. We assessed differences in governance system components of local institutions, including land tenure, decision‐making autonomy by forest users, and official and de facto processes of rule formation, monitoring, and enforcement among the three management strategies. We also assessed differences in frequencies of prohibited logging and subsistence pole cutting, and measures of forest condition. An adjacent research forest served as an ecological reference for comparison of forest conditions. Governance was similar for comanaged and centralized management, whereas communal managers had greater tenure security and decision‐making autonomy over the use and management of their forest. There was significantly less illegal logging in the communal forest, but subsistence pole cutting was common across all management strategies. The comanaged forest was most disturbed by recent logging and pole cutting, as were peripheral areas of the larger centralized forest. This manifested in more degraded indicators of forest conditions (lower mean tree size, basal area, density of trees ≥ 90 cm dbh, and aboveground biomass and higher overall stem density). Greater tenure security and institutional autonomy of the communal strategy contributed to more effective management, less illegal logging, and maintenance of good forest conditions, but generating livelihood benefits was a challenge for both decentralized strategies. Our results underscore the importance of well‐designed institutional arrangements in forest management and illustrate mechanisms for improved forest governance and conservation in the context of Tanzanian decentralization reforms. 相似文献
100.
Dynamics of Bacterial Abundance,Biomass, Activity,and Community Composition in the Oligotrophic Traunsee and the Traun River (Austria) 总被引:1,自引:0,他引:1
Klammer Susanne Posch Thomas Sonntag Bettina Griebler Christian Mindl Birgit Psenner Roland 《Water, Air, & Soil Pollution: Focus》2002,2(4):137-163
The holomictic Traunsee is the deepest and second largest lakein Austria. The special characteristic of this ecosystem isthe fact that local salt and soda industries presumably alterthe lake by the discharge of waste materials. Since thebeginning of the 20th century salt and soda works areannually releasing up to 50,000 tons of solid wastes and up to150,000 tons of chloride into Traunsee. To assess potentialeffects of these anthropogenic impacts on the bacterioplanktonthree sampling sites, influenced as well as not influenced bythe industrial discharge, were chosen for comparison andsampled monthly from November 1997 to October 1998. Bacterialabundance ranged between 0.4 to 3.0 × 106 cells ml-1 with decreasing numbers along the depth profile. Theproportion of actively respiring bacteria, i.e. INT [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride]reducing cells, never exceeded 10% of DAPI (4',6'-diamidino-2-phenylindole) stained cells. Fluorescence in situ hybridization (FISH) was used to examine the seasonal and spatial distribution of dominant phylogenetic groups of thebacterioplankton. Up to 84% of bacteria detected with DAPIcould be detected via FISH applying the universal bacterialprobe EUB338. Percentages of alpha- and beta-Proteobacteriaand members of the Cytophaga-Flavobacterium cluster did notexceed 60% of DAPI-stained cells.Beta-Proteobacteriaappeared to be the most abundant group, not only in Traunsee butalso in two reference lakes, Attersee and Hallstättersee. No significant differences in any of the bacterial parameters couldbe detected between the three sampling sites and all measurementswere found in the range reported for oligotrophic lakes. The highdischarge of the Traun River, resulting in a lake water renewaltime of only one year, may diminish possible effects of industrial waste discharge in the pelagic zone. 相似文献