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41.
Estimation and characterization of PCDD/Fs, dl-PCBs, PCNs, HxCBz and PeCBz emissions from magnesium metallurgy facilities in China 总被引:2,自引:0,他引:2
Magnesium production is considered to be one potential source of unintentional persistent organic pollutants (unintentional POPs). However, studies on the emissions of unintentional POPs from magnesium metallurgy are still lacking. Emissions of unintentional POPs, such as polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated naphthalenes (PCNs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz) are covered under the Stockholm Convention. In this study, these emissions were investigated through a magnesium smelting process. Stack gas and fly ash samples from a typical magnesium plant in China were collected and analyzed to estimate the emissions of unintentional POPs from magnesium metallurgy. Emissions factors of 412 ng TEQ t−1 for PCDD/Fs, 18.6 ng TEQ t−1 for dl-PCBs, 3329 μg t−1 for PCNs, 820 μg t−1 for HxCBz, and 1326 μg t−1 for PeCBz were obtained in 2009. Annual emissions from magnesium metallurgy in China were estimated to be 0.46 g WHO-TEQ for PCDD/Fs and dl-PCBs, 1651 g for PCNs, 403 g for HxCBz and 653 g for PeCBz, respectively. 相似文献
42.
The effectiveness of different conservation policies is debated, but the policies are rarely evaluated quantitatively. A voluntary or 'soft' policy based mainly on education provides information about ecosystems and effects of land use, to encourage conservation action. Swedish forestry relies mainly on soft policy, with substantial resources for education and advice to more than 200,000 forest owners, while legal regulation is weak. Increased retention of broadleaved trees at clear-cutting, with environmental benefits in the conifer-dominated forestry, is important in the policy. We used the Swedish National Forest Inventory to analyse this policy for young forests in southern Sweden. Between 1983-1987 and 1998-2002 the policy had no positive effect on saplings (1.3m tall to 4.9 cm dbh) of birch, oak, beech and other species that mostly decreased in density, due to planting of conifers and browsing by ungulates. However, broadleaved conservation trees (>or=15 cm dbh) increased in density, e.g. to about one oak and six birches per ha in young coniferous forest in 1998-2002. The relative increase in density was higher for large (>or=20 cm dbh) than for small trees (15-20 cm dbh). The density of conservation trees was higher on forestland of high than of low productivity. Thus, the soft conservation policy did not influence regeneration of saplings in this type of forestry system, but large broadleaved trees were increasingly saved at 'clear-cuttings'. Advice and educational programmes probably contributed to this result. A continued increase in conservation trees at harvest may require economical support to forest owners. 相似文献
43.
Shinji Ueda Yoshihito Ohtsuka Kunio Kondo Shun'ichi Hisamatsu 《Journal of environmental radioactivity》2009,100(10):835-840
We investigated the vertical profiles of 239+240Pu, 137Cs, and excess 210Pb (210Pbex) in sediment core samples obtained from two freshwater lakes and two brackish lakes situated near the first commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan, before the final test of the plant using actual spent nuclear fuel. The inventory of 239+240Pu in those lakes was larger than that in soil in Rokkasho, which indicated the inflow of 239+240Pu from the catchment area in addition to direct deposition on the lake surfaces. The 137Cs inventory in sediments of the brackish lakes was lower than that in the soil, which showed that part of the 137Cs was removed from the sediments by the brackish water or that it was not deposited into the sediments, because of the high solubility of Cs in brackish water. The 137Cs inventory in sediments of the freshwater lakes was higher than that of the brackish lakes, and comparable with that in soil except for one core sample out of four. The 239+240Pu/137Cs ratio in freshwater lake sediments was higher than that in soil, and that indicated that part of the 137Cs was lost from the sediments. The low inventory of 137Cs may be attributable to competition for absorption sites in sediments with ammonium ions formed in the reducing environment which occurs from summer to fall in the sediments. Those data will be used as background data on the artificial radionuclides in the lakes to assess the effect of released radionuclides on their concentrations. 相似文献
44.
土地利用变化及林业(LUCF)活动是生态固碳最重要手段。研究确定LUCF温室气体排放核算制度和方法,对平衡碳排放、开展全国统一碳市场交易具有重要基础作用。在综述LUCF温室气体核算理论和方法基础上,借鉴IPCC指南和《省级温室气体清单编制指南(试行)》推荐的基本方法,构建了符合地域特色的LUCF温室气体排放核算制度和方法。采用2014年第九次国家森林资源清查数据,以全国低碳试点省陕西省为实证对象,初步核算了陕西省LUCF温室气体的净排放量,并从排放能力、排放结构和空间特征等角度揭示了陕西省LUCF温室气体的排放特征。结果显示:(1)2014年,陕西省LUCF温室气体净吸收量为1 698.42万t CO_2e,其中森林及其他木质生物质碳贮量净吸收1 852.67万t CO2e,森林转化净排放154.25万t CO_2e。(2)乔木林等优势树种,是陕西省LUCF温室气体排放中重要的固碳源(吸收源)。(3)陕南地区是重要固碳贡献区,陕北地区森林固碳能力较差。最后,针对LUCF温室气体排放核算制度和方法不够完善、森林固碳能力差异较大、区域固碳分化严重等问题,提出了健全温室气体核算制度、平衡森林资源空间分布、改善固碳树种结构等加强陕西省LUCF活动应对气候变化统计核算制度和能力建设的基本措施。 相似文献
45.
以天津市2010年污染源普查数据中SO2、NOx及颗粒物排放数据以及各行业挥发性有机物调查核算数据为主要数据源,制作天津市大气污染物排放清单,用MM5模型模拟2010年天津市地区1、4、7、10月的气象场,通过CMAQ模型,设置不同计算情景,分析天津市ρ(O3)变化与NOx及挥发性有机物的排放量变化关系。结果表明,天津市的O3生成处于VOCs控制区,随着天津市NOx减排力度的不断加大,ρ(O3)可能呈上升趋势,在夏季,需要削减40%以上挥发性有机物,以避免ρ(O3)进一步上升。 相似文献
46.
Yangjian Zhang Hong S. He William D. Dijak Jian Yang Stephen R. Shifley Brian J. Palik 《Environmental management》2009,44(2):312-323
To achieve the overall objective of restoring natural environment and sustainable resource usability, each forest management
practice effect needs to be predicted using a simulation model. Previous simulation efforts were typically confined to public
land. Comprehensive forest management practices entail incorporating interactions between public and private land. To make
inclusion of private land into management planning feasible at the regional scale, this study uses a new method of combining
Forest Inventory and Analysis (FIA) data with remotely sensed forest group data to retrieve detailed species composition and
age information for the Missouri Ozark Highlands. Remote sensed forest group and land form data inferred from topography were
integrated to produce distinct combinations (ecotypes). Forest types and size classes were assigned to ecotypes based on their
proportions in the FIA data. Then tree species and tree age determined from FIA subplots stratified by forest type and size
class were assigned to pixels for the entire study area. The resulting species composition map can improve simulation model
performance in that it has spatially explicit and continuous information of dominant and associated species, and tree ages
that are unavailable from either satellite imagery or forest inventory data. In addition, the resulting species map revealed
that public land and private land in Ozark Highlands differ in species composition and stand size. Shortleaf pine is a co-dominant
species in public land, whereas it becomes a minor species in private land. Public forest is older than private forest. Both
public and private forests have deviated from historical forest condition in terms of species composition. Based on possible
reasons causing the deviation discussed in this study, corresponding management avenues that can assist in restoring natural
environment were recommended. 相似文献
47.
The USDA Forest Service, Forest Inventory and Analysis program (FIA) recently produced a nationwide map of forest biomass
by modeling biomass collected on forest inventory plots as nonparametric functions of moderate resolution satellite data and
other environmental variables using Cubist software. Efforts are underway to develop methods to enhance this initial map.
We explored the possibility of modeling spatial structure to make such improvements. Spatial structure in the field biomass
data as well as in residuals from the map was investigated across 18 ecological zones in the Interior Western U.S. Exploratory
tools included directional graphs of summary statistics, three dimensional maps, Moran’s I correlograms, and variograms. Where
spatial pattern was present, field and residual biomass were kriged, and predictions made for an independent test set were
evaluated for improvement over predictions in the initial biomass map. While kriging has some potential benefit when analyzing
the field data and exploring spatial structure, kriging residuals resulted in little or no improvement in the initial biomass
map developed using Cubist software. Stationarity assumptions, variogram behavior, and appropriate model fitting strategies
are discussed. 相似文献
48.
Martijn Mes Marco Schutten Arturo Pérez Rivera 《Waste management (New York, N.Y.)》2014,34(9):1564-1576
We consider the problem of collecting waste from sensor equipped underground containers. These sensors enable the use of a dynamic collection policy. The problem, which is known as a reverse inventory routing problem, involves decisions regarding routing and container selection. In more dense networks, the latter becomes more important. To cope with uncertainty in deposit volumes and with fluctuations due to daily and seasonal effects, we need an anticipatory policy that balances the workload over time. We propose a relatively simple heuristic consisting of several tunable parameters depending on the day of the week. We tune the parameters of this policy using optimal learning techniques combined with simulation. We illustrate our approach using a real life problem instance of a waste collection company, located in The Netherlands, and perform experiments on several other instances. For our case study, we show that costs savings up to 40% are possible by optimizing the parameters. 相似文献
49.
Daniel Press 《Environmental management》1996,20(5):725-730
Toxic Release Inventory (TRI) data were used to compare average releases (kilograms per metric ton) of paper mills using primarily recovered wastepaper versus mills using primarily virgin wood fiber. Annual releases, for 79 mills, of chlorine, chlorine dioxide, chloroform, acids (hydrochloric and sulfuric), volatile organics (methyl ethyl ketone, methanol, and acetone), and ammonia were compared over the years 1987–1992. Both types of mills reported generally lower toxic releases in 1992 than in 1987; however, toxic releases in all categories were significantly lower from mills using recovered wastepaper than from mills using virgin wood fiber, strongly demonstrating that recycling has added benefits beyond reduced resource consumption. These results suggest that environmental policy should concentrate as much on increasing demand for recycled paper and developing wastepaper collection infrastructure as it does on end-of-pipe pollution abatement. 相似文献
50.
Farrell AE 《Environmental monitoring and assessment》2005,107(1-3):59-80
The Montreal Process was formed in 1994 to develop an internationally agreed upon set of criteria and indicators for the conservation and sustainable management of temperate and boreal forests. In response to this initiative, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring (FHM) programs of the United States Department of Agriculture Forest Service have implemented soil measurements as part of a national monitoring program to address specific questions related to the conservation of soil and water resources. Integration of soil assessments into the national FIA program provides for systematic monitoring of soil properties across all forested regions of the U.S. using standardized collection, laboratory, and statistical procedures that are compatible with existing forest inventory data. The resulting information will provide quantitative benchmarks for regional, national, and international reporting on sustainable forest management and enhance our understanding of management effects on soil quality. This paper presents an overview of the FIA soil monitoring program, outlines the field and laboratory protocols as currently implemented, and provides examples of how these data may be used to assess indicators of sustainable management as defined by the Montreal Process. 相似文献