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921.
Bergknut M Laudon H Jansson S Larsson A Gocht T Wiberg K 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1592-1598
The mass-balance between diffuse atmospheric deposition of organic pollutants, amount of pollutants retained by the terrestrial environment, and levels of pollutants released to surface stream waters was studied in a pristine northern boreal catchment. This was done by comparing the input of atmospheric deposition of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and PCBs with the amounts exported to surface waters. Two types of deposition samplers were used, equipped with a glass fibre thimble and an Amberlite sampler respectively. The measured fluxes showed clear seasonality, with most of the input and export occurring during winter and spring flood, respectively. The mass balance calculations indicates that the boreal landscape is an effective sink for PCDD/Fs and PCBs, as 96.0-99.9 % of received bulk deposition was retained, suggesting that organic pollutants will continue to impact stream water in the region for an extended period of time. 相似文献
922.
923.
Mosses and lichens are useful biological indicators of environmental contamination for a variety of metals and radionuclides of both natural and artificial origin. These plants lack a well-developed root system and rely largely on atmospheric deposition for nourishment. Therefore in the study, different lichens (Cladonia convoluta, Cladonia foliacea) and mosses (Homalothecium sericeum, Hypnum lacunosum, Hypnum cupressiforme, Tortella tortuosa, Didymodon acutus, Syntrichia ruralis, Syntrichia intermedia, Pterogonium graciale, Isothecium alopecuroides, Pleurochatae squarrosa) were collected around the Yata?an (Mu?la), Soma (Manisa), Seyitömer - Tunçbilek (Kütahya) coal-fired power plants and investigated for potential use as biomonitors for 210Po and 210Pb deposition. While the activity concentrations of 210Po and 210Pb in lichens are in the ranges of 151 ± 7-593 ± 21 and 97 ± 5-364 ± 13 Bq kg−1, for mosses the ranges for 210Po and 210Pb are 124 ± 5-1125 ± 38 and 113 ± 4-490 ± 17 Bq kg−1, respectively. In the study, the moss samples were observed to accumulate more 210Po and 210Pb compared to lichens. While the most suitable biomonitor was a moss species (H. lacunosum) for Yata?an (Mu?la), it was another moss species (S. intermedia) for Soma (Manisa) and Seyitömer - Tunçbilek (Kütahya) sites. 210Po concentrations were found higher than 210Pb concentrations at the all sampling stations. 相似文献
924.
Soil acidification has been of concern in the oil sands region in Alberta due to increased acid deposition. Using the canopy budget model, and accounting for H+ canopy leaching by organic acids, we determined sources and sinks of H+ in throughfall in jack pine (Pinus banksiana) and trembling aspen (Populus tremuloides) stands in two watersheds from 2006 to 2009. In pine stands, H+ deposition was greater in throughfall than in bulk precipitation while the opposite was true in aspen stands. The annual H+ interception deposition was 148.8-193.8 and 49.7-70.0 molc ha−1 in pine and aspen stands, respectively; while the annual H+ canopy leaching was 127.1-128.7 and 0.0-6.0 molc ha−1, respectively. The greater H+ supply in pine stands was caused by greater interception deposition of SO42− and organic acids released from the pine canopy. Such findings have significant implications for establishing critical loads for various ecosystems in the oil sands region. 相似文献
925.
926.
湿式镁法烟气脱硫技术发展综述 总被引:4,自引:0,他引:4
介绍了湿式镁法烟气脱硫工艺的历史,评述了国内镁法烟气脱硫技术的发展现状,以及镁法烟气脱硫副产物的利用。 相似文献
927.
G.T. Geertsema B.G.J. Wichers Schreur 《Atmospheric environment (Oxford, England : 1994)》2009,43(32):4924-4934
The predictive potential of air quality models and thus their value in emergency management and public health support are critically dependent on the quality of their meteorological inputs. The atmospheric flow is the primary cause of the dispersion of airborne substances. The scavenging of pollutants by cloud particles and precipitation is an important sink of atmospheric pollution and subsequently determines the spatial distribution of the deposition of pollutants. The long-standing problem of the spin-up of clouds and precipitation in numerical weather prediction models limits the accuracy of the prediction of short-range dispersion and deposition from local sources. The resulting errors in the atmospheric concentration of pollutants also affect the initial conditions for the calculation of the long-range transport of these pollutants. Customary the spin-up problem is avoided by only using NWP (Numerical Weather Prediction) forecasts with a lead time greater than the spin-up time of the model. Due to the increase of uncertainty with forecast range this reduces the quality of the associated forecasts of the atmospheric flow.In this article recent improvements through diabatic initialization in the spin-up of large-scale precipitation in the Hirlam NWP model are discussed. In a synthetic example using a puff dispersion model the effect is demonstrated of these improvements on the deposition and dispersion of pollutants with a high scavenging coefficient, such as sulphur, and a low scavenging coefficient, such as cesium-137. The analysis presented in this article leads to the conclusion that, at least for situations where large-scale precipitation dominates, the improved model has a limited spin-up so that its full forecast range can be used. The implication for dispersion modeling is that the improved model is particularly useful for short-range forecasts and the calculation of local deposition. The sensitivity of the hydrological processes to proper initialization implies that the spin-up problem may reoccur with changes in the model and increased model resolution. Spin-up should be an ongoing concern for atmospheric modelers. 相似文献
928.
929.
湿法烟气脱硫除雾器设计选型和维护 总被引:1,自引:0,他引:1
分析了除雾器叶片的设计要求,比较了平板型和屋脊型除雾器的特点。从运行、维护的角度出发,建议建立除雾器检测和冲洗制度,以确保除雾器的安全、正常运行。 相似文献
930.
摘要:通过河南鹤壁丰鹤火电厂2×600MW湿法脱硫的工程实践,结合国内其他脱硫工程的应用经验.对湿法脱硫工艺中增压风机的运行控制进行探讨。 相似文献