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151.
152.
In January–February 1991, about 1 million m3 of crude oil were released into the Arabian Gulf as a means of ecological warfare. A stretch of 644 km along the Saudi Arabian coast was heavily polluted over a width between a few meters and more than one kilometer. In four studies performed between March 1991 and April 1993 the state of representative areas of the affected coast was examined with the result that only minor changes were found in those oiled zones which are seldom inundated by the tides. Technical measures up to 1993 did not exceed the test level. A biological regeneration process is in progress which was not recognized as such in analyses of previous coastal oil pollution. Cyanobacterial mats, containing hydrocarbon-degrading bacteria, grow on oiled sediments which are regularly reached by tidal water. Shrinking and fracturing of the stable tar crusts starts a process of loosening and degrading of aged hydrocarbons.  相似文献   
153.
Haloacetic acids are atmospheric oxidation products of airborne C2-halocarbons which are important solvents and propellants. Levels of trichloroacetate (TCA) in conifer needles from mountain ranges in Germany (Black Forest, Erzgebirge) and from two sites in Finland are compared; TCA is present in conifer needles at concentrations up to 0.7 μmol/kg, MCA up to 0.2 μmol/kg. At the Finnish sites, TCA-concentrations and branch degeneration symptoms of Scots pine are correlated. Monochloroacetate (MCA) has been determined in needle samples from Southern Germany in concentrations exceeding its phytotoxicity threshold towards photoautotrophic organisms. Data on atmospheric chloroacetate levels in Germany are also given; ambient air levels of chloroacetic acids range from about 2 pmol/m3 (TCA) to 390 pmol/m3 (MCA). TCA and dichloroacetic acid (DCA) arise from atmospheric oxidation of airborne C2-chlorocarbons, while the source of MCA is not yet known; several tentative pathways are suggested.  相似文献   
154.
Stability and genetic variation of a structural protein   总被引:1,自引:0,他引:1  
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155.
Agri-environmental measures are payments to farmers to reduce environmental risks or to preserve cultivated landscapes. These measures are codified in European Union regulations. Poor spatial targeting is one of the major causes of low cost-effectiveness in agri-environmental measures. Existing studies on spatial targeting focus primarily on selected individual measures; hence, they do not allow for conclusions at the program level, where the planning and implementing of decisions on a number of different measures has to be made. In this study, we analyzed the impacts of two spatial targeting options (targeting of erosion-reducing measures on erosion vulnerable areas; targeting of grassland extensification on N-pollution vulnerable areas) on the cost-effectiveness of the single measures and the entire agri-environmental program of the federal state of Brandenburg in Germany. The methodological steps included an analysis of empirical data on land use and program participation, an expert-based environmental impact assessment and a spatial allocation procedure based on linear programming. The environmental impact assessment delivered goal-specific index values for each measures-land parcel combination expressing the suitability of the measures for contributing to four regionally relevant program objectives. The cost-effectiveness of the measures and the program were calculated by putting budgetary costs in relation to the achieved environmental index sum. The calculated cost-effectiveness of the program in 2006 was 89.6% of the simulated optimal cost-effectiveness. The spatial targeting of erosion-reducing measures on erosion vulnerable areas caused an increase in the cost-effectiveness at the measures level and almost no changes at the program level. The spatial targeting of grassland extensification on N-pollution vulnerable areas, despite also improving the cost-effectiveness of this measure, had negative effects on the cost-effectiveness of the program.  相似文献   
156.
BACKGROUND, AIMS AND SCOPE: Over the last few years there has been extensive research for new indicators providing information about deposition resulting from road traffic and tunnel experiments received special attention in emission research. Mosses have been used for the estimation of atmospheric heavy metal and PAH depositions for more than three decades, although they were used only a few times for estimating ambient air pollution caused by traffic. In the current study, the suitability of using a moss species for monitoring road traffic emissions inside a tunnel was evaluated. This was a first-time ever attempt to use plants (mosses) as bioindicators in a tunnel experiment. Specifically, two relevant questions were examined: 1) Do mosses accumulate toxic substances derived from road traffic emissions under the extremely adverse conditions which can be found in a tunnel, and 2) Which substances can mainly be attributed to road traffic emissions and therefore be taken as efficient and reliable indicators for motor vehicles? METHODS: For the first time a biomonitor (the moss species Hylocomium splendens (Hedwig) B.S.G.) was used in a road tunnel experiment to analyse emissions from road traffic. Moss samples were exposed for four weeks in wooden frames (size 10 cm x 10 cm), covered by a thin plastic net with a mesh size of 1 cm x 1 cm. 17 elements, mainly heavy metals, and the 16 EPA-PAHs together with coronene were analysed by ICP-AES, AAS and GC-MSD. RESULTS: Enrichment factors, calculated by comparing post-experiment concentrations to those of a background site, were high for most PAHs, especially benzo(g,h,i)perylene (150.7), coronene (134.7), benzo(a)anthracene (125.0), indeno(1,2,3-c,d)pyrene (79.8), chrysene (78.1), pyrene (69.6) and benzo(b)-fluoranthene (67.4), and among the other elements for Sb (73.1), Mo (59.6), Cr (33.9), As (24.1), Cu (19.6), and Zn (17.1). All these substances can thus be taken as indicators for road traffic pollution. Concentrations were also significantly higher in the tunnel mosses for all investigated substances than along busy roads outside tunnels. Cluster analysis revealed groups of substances which could sensibly be attributed to various sources (abrasion processes, Diesel combustion) and enrichment in the various particle size classes. DISCUSSION: The extreme high concentrations in the analysed moss samples from inside the tunnel were due to higher concentrations in the ambient tunnel air, and the fact that already deposited chemical substances are not lost by rain, as well as efficient uptake capacities even under the extremely adverse conditions in a tunnel. In accordance with previous studies our results suggest that PAHs are better indicators for emissions from the burning process than heavy metals. CONCLUSIONS: As in open fields, mosses are suitable indicators for monitoring traffic emissions in tunnels. In addition to biomonitoring in open fields, in tunnel experiments mosses are even better indicators, because the confounding effects of other sources of pollution and the 'noise' in the accumulation process (e.g. washout through wet deposition) are minimised. The results of our study demonstrate the usefulness of mosses for surveying heavy metals and PAH emissions and deposition arising from road traffic sources, even under the extremely adverse conditions of the tunnel environment. RECOMMENDATION: It can be considered that biomonitors like mosses are a suitable alternative to technical particle filters inside tunnels. They are easy to handle, low in costs and valuable information regarding traffic emissions can be obtained. PERSPECTIVE: The results of this pilot-study proved the feasibility of the method, however, should be corroborated by further investigations based on a sample set that allows for generalization of the findings and might even include other moss species. A comparison of technical measurements with the biomonitoring method could lead to a more general acceptance of the results.  相似文献   
157.
Several catastrophic events in the process industry have caused extensive damage to life and property and have forever changed the process safety landscape. Despite the commitment from the industry, incidents still occur with similar root causes, impacting major companies in various ways. This work examines the financial impact of such incidents on the stability and future of affected companies in different industries. Several devastating incidents were analyzed to evaluate the direct impact in the short- and long-term and to discuss factors influencing the ability of affected companies to withstand the consequence of catastrophic events.  相似文献   
158.
Emulsified zero‐valent iron (EZVI) is a surfactant‐stabilized, biodegradable emulsion that forms droplets consisting of a liquid‐oil membrane surrounding zero‐valent iron (ZVI) particles in water. This article summarizes the results obtained during the first field‐scale deployment of EZVI at NASA's Launch Complex 34 (LC34) located on Cape Canaveral Air Force Station, Florida, in August 2002 and presents the results of recent follow‐on laboratory tests evaluating the mechanisms, which contribute to the performance of the technology. The field‐scale demonstration evaluated the performance of EZVI containing nanoscale zero‐valent iron (NZVI) when applied to dense, nonaqueous phase liquid (DNAPL) trichloroethylene (TCE) in the saturated zone. Results of the field demonstration indicate substantial reductions in TCE soil concentrations (greater than 80 percent) at all but two soil boring locations and significant reductions in TCE groundwater concentrations (e.g., 60 percent to 100 percent) at all depths targeted with EZVI. Laboratory tests conducted in 2005 suggest that both NZVI particles and EZVI containing NZVI can provide significant reductions in TCE mass when used to treat TCE DNAPL in small test reactors. However, EZVI was able to reduce TCE concentrations to lower levels than were obtained with NZVI alone, likely as a result of the combined impact of sequestration of the TCE into the oil phase and degradation of the TCE with the NZVI. © 2006 Wiley Periodicals, Inc.  相似文献   
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