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541.
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Volatile organic compounds were determined in stack-gas emissions from the residential burning of brown-coal briquets using adsorptive enrichment on hydrophobic adsorbents, thermal desorption and capillary-gas chromatographic analysis. 152 compounds were identified and quantified. Quantitative emission factors of the identified individual compounds were determined in relation to the amount of the fuel used. These factors permit assessment of the pollution of the city of Leipzig with volatile organic compounds resulting from the burning of indigenous lignite.  相似文献   
545.
For the pilotproject ?Effect Monitoring — Biomonitoring of Immission Effects in the Testing Area of Munich”, standardized grass cultures were exposed at 19 locations during 10 series for two weeks each. The grass was analyzed for the accumulation of lead, antimony arsenic, cadmium, and copper. Highest accumulation was observed with antimony near traffic situations. The comparison of the results from the different sampling points identifies motor vehicle traffic as the source of antimony. First examinations of brake linings support this conclusion. Lead is only slightly increased near traffic. Immission-caused copper contents in the grass were found near the overhead tramway cables. The accumulation detection limits for arsenic and cadmium were not exceeded at any of the measuring points.  相似文献   
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Atmospheric heavy metals, (Pb, Cd, Cu, Zn), PAHs, and PCBs, depositions were monitored in scots pine needles during a monitoring network programme (Monitoring Programme Natural Budget Berlin and Environs) in 1991 in the city of Berlin, and the surrounding rural areas of Brandenburg (Germany). The total area of the network covered 3,000 km2. The passive monitoring technique is based on the fact that the concentrations of heavy metals, PAH’s and PCB’s in the needles are closely correlated to atmospheric depositions/emissions. The objectives of the project were to characterize qualitatively and quantitatively the regional atmospheric deposition patterns of heavy metals, PAH’s and PCB’s in rural and polluted urban areas of Berlin and Brandenburg. The indication of the locations which could be characterized as heavy metals, PAH and PCB pollution sources was also targetted in this investigation. After conclusion, comparison with similar studies conducted in different parts of Germany and Europe would be possible. The regional background deposition levels showed different distribution patterns. The lead and PAH concentrations in the pine needles were closely correlated to the locations of combustion sources petrol, oil, brown coal and heavy traffic activities. The PCB and cadmium concentration levels in the pine needles represented a more ubiquitous distribution pattern.  相似文献   
548.
Major objectives were to provide a comprehensive dataset on beach macro-litter for parts of the southern Baltic Sea and to analyse if the methodology is fully applicable and a suitable monitoring method in the Baltic. We carried out a regular macro litter beach monitoring (OSPAR methodology, 4 time a year) on 35 beaches along the German and Lithuanian Baltic coast over 2–5 years. Additional experiments addressed the subjectivity of the field surveys and spatio-temporal variability on different scales. We observed no seasonality of the data and a monthly compared to a 3-monthly sampling resulted in 3 times higher annual item numbers. Along the Lithuanian coast, the average number of items per survey varied between 138 and 340 and along the German Baltic coast between 7 and 404, with a median value of 47. All data showed a very high spatio-temporal variability. Using the Matrix Scoring Technique we assessed beach litter sources. With 50% tourism and recreation was the most important source. 3D–transport simulations helped to explain the minor role of shipping as a source and, compared to the North Sea, the low numbers of items on German Baltic beaches. Floating litter had a short duration time in the western Baltic Sea and offshore drift dominated. Further, the common regular beach cleanings reduced the potential for local litter accumulation and translocation. We suggest a monitoring system on 14 Baltic beaches in Germany and 2 in Lithuania and provide cost calculations. The analysis of macro-litter in cormorant nesting material and the search for beached dead animals did not show any result. We can conclude that the macro-litter beach monitoring method is less suitable for Baltic beaches and should only serve as a complementary method in combination with others.  相似文献   
549.
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Entanglement in fixed fishing gear affects whales worldwide. In the United States, deaths of North Atlantic right (Eubalaena glacialis) and humpback whales (Megaptera novaeangliae) have exceeded management limits for decades. We examined live and dead whales entangled in fishing gear along the U.S. East Coast and the Canadian Maritimes from 1994 to 2010. We recorded whale species, age, and injury severity and determined rope polymer type, breaking strength, and diameter of the fishing gear. For the 132 retrieved ropes from 70 cases, tested breaking strength range was 0.80–39.63 kN (kiloNewtons) and the mean was 11.64 kN (SD 8.29), which is 26% lower than strength at manufacture (range 2.89–53.38 kN, mean = 15.70 kN [9.89]). Median rope diameter was 9.5 mm. Right and humpback whales were found in ropes with significantly stronger breaking strengths at time of manufacture than minke whales (Balaenoptera acuturostrata) (19.30, 17.13, and 10.47 mean kN, respectively). Adult right whales were found in stronger ropes (mean 34.09 kN) than juvenile right whales (mean 15.33 kN) and than all humpback whale age classes (mean 17.37 kN). For right whales, severity of injuries increased since the mid 1980s, possibly due to changes in rope manufacturing in the mid 1990s that resulted in production of stronger ropes at the same diameter. Our results suggest that broad adoption of ropes with breaking strengths of ≤7.56 kN (≤1700 lbsf) could reduce the number of life‐threatening entanglements for large whales by at least 72%, and yet could provide sufficient strength to withstand the routine forces involved in many fishing operations. A reduction of this magnitude would achieve nearly all the mitigation legally required for U.S. stocks of North Atlantic right and humpback whales. Ropes with reduced breaking strength should be developed and tested to determine the feasibility of their use in a variety of fisheries.  相似文献   
550.
Werner EE  Peacor SD 《Ecology》2006,87(2):347-361
Indirect effects propagated through intervening species in a food web have important effects on community properties. Traditionally, these indirect effects have been conceptualized as mediated through density changes of the intervening species, but it is becoming increasingly apparent that those mediated through trait (phenotypic) responses also can be very important. Because density- and trait-mediated indirect effects have different properties, it is critical that we understand the mechanisms of transmission in order to predict how they will interact, and when or where they will be important. In this study, we examined the mechanisms and consequences of the lethal (density-mediated) and nonlethal (trait-mediated) effects of a larval odonate predator on a guild of four herbivore species (a larval anuran and three species of snails) and their resources. We also manipulated system productivity in order to explore the effects of environmental context on the transmission of these two types of indirect effects. We show that trait-mediated effects arising from the predator can be very strong relative to density-mediated effects on both the competing herbivores and the species composition and production of their resources. A number of these indirect effects are shown to be contingent on productivity of the system. We further present evidence that trait- and density-mediated indirect effects originating from a predator may be transmitted independently through different routes in a food web, particularly when spatial responses of the transmitting prey are involved. Finally, effects on prey growth due to trait responses to the predator varied from negative to positive in predictable ways as a function of time and indirect effects on the larger food web. These results indicate the important role that trait-mediated indirect effects can play in trophic cascades and keystone predator interactions, and we discuss how the mechanisms involved can be incorporated in theory.  相似文献   
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