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101.
The effect of polarity on the oxidation of Hg0 was examined in the presence of O2 via a pulsed corona discharge (PCD). The experimental result showed no difference in the energy yield of Hg0 oxidation at both positive and negative PCDs (∼8 μg Hg W h−1 at following conditions: total flow rate = 2 L min−1 (Hg0 = 50 μg N m−3, O2 = 10%, and N2 balance), temperature = 150 °C, and specific energy density = 5-15 W h N m−3). This suggests that the positive PCD process used to control gaseous air pollutants may play an essential key role in Hg0 oxidation because it consumes enough energy (∼15 W h N m−3) but an electrical precipitator could not because it consumes less energy (∼0.3 W h N m−3) to oxidize Hg0. 相似文献
102.
贵阳市一居民区大气颗粒态汞的污染状况 总被引:2,自引:0,他引:2
2004年4、7、8、11、12月采用微型捕集管-冷原子荧光光谱法对贵阳市一个居民区大气中的痕量颗粒态总汞(TPM)进行了测定。结果表明:TPM日均浓度范围是0.149~4.853 ng.m-3,平均值是1.091 ng.m-3,显著高于背景参考值1~86 pg.m-3;TPM浓度采暖期大于非采暖期,夜间通常大于白昼;TPM与大气气态总汞(TGM)可能具有同源性;燃煤、垃圾焚烧以及周边工厂排放的含尘烟气可能是居民区大气颗粒态汞的主要人为来源。 相似文献
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104.
Danuta Baralkiewicz Hanka Gramowska Ryszard Gołdyn Wiesław Wasiak Katarzyna Kowalczewska-Madura 《Chemistry and Ecology》2013,29(2):93-103
Sediment samples were analysed for mercury and methylmercury content in different parts of the bottom sediment of Swarz ?dzkie Lake, which were influenced by different external pollution sources. The results of determination with two methods of mineralization using two separate media (HNO3/H2O2 and HF) were compared. The accuracy of the studied methods was analysed using certified reference material IAEA 405 of river sediment. The recovery of mercury was satisfactory and ranged from 97.5 to 98.8%. Methylmercury compounds in the studied sediments were found in limited concentrations. Their concentrations ranged from 0.26 to 58.1 μg kg?1, i.e. 1.0–7.4% of the total mercury content. The depth profile displayed high values of both total and methylmercury content at a depth of 10–20 cm, related to the heavy pollution of the lake in the 1980s. Canonical analysis displayed the relationship of both total mercury and methylmercury concentrations with organic matter and phosphorus content in bottom sediments. 相似文献
105.
Amleto A. Pucci Douglas A. Harriman Elisabeth M. Ervin Lisa Bratton Alison Gordon 《Journal of the American Water Resources Association》1989,25(6):1267-1272
ABSTRACT: The U.S. Geological Survey collected ground-water samples from the upper and middle aquifers of the Potomac-Raritan-Magothy aquifer system in a 400-square-mile area of New Jersey from 1984 through 1986. Concentrations of lead were greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 50 micrograms per liter in water from 16 of 239 wells. The cencentrations of cadmium were greater than the MCL of 10 micrograms per liter in water from 10 to 241 wells. One-half of the wells that exceeded the lead MCL were in known areas of saltwater intrusion, as were all 10 wells that exceeded the cadmium MCL. The association of elevated concentrations of these metals with elevated concentrations of chloride indicates a mochanism related to saltwater intrusion. 相似文献
106.
The present study tested the separate and the interactive pollution effects of cadmium and mercury on the electrophoretically detected allelic isozyme frequencies of the enzyme phosphoglucose isomerase for two species of littoral marine gastropods —Littorina punctata andL. neritoides — and the enzyme amino peptidase forL. neritoides. Our results indicate differential survivorship of allelic isozyme genotypes specific for each type of pollutant and for their interaction, as well as trends common to all pollutants. Theoretically the results reflect the adaptive nature of at least some allozymic genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Practically, the results reinforce earlier conclusions that changes in the frequency of allelic isozymes may be used as a genetic monitor of pollution. 相似文献
107.
Dinshaw N. Contractor 《Journal of the American Water Resources Association》1983,19(5):745-751
ABSTRACT This paper deals with the application of a two-dimensional, saltwater intrusion model to the aquifer in Northern Guam. The model used finite element theory and the Galerkin, weighted-residual technique as its basis. The Northern Guam lens was discretized into 299 linear, triangular elements and 189 nodes. The model was calibrated using 1978 hydrologic data. The output of the model was compared with measured water levels in six observation wells. The calibrated values of permeability and porosity were then used to verify the model using 1979 data. A calibrated and verified model can be used to make an infinite variety of management and planning studies. In this study, three applications are provided that would be considered typical management runs. Steady state runs were made to compare the four conditions of no pumping, 1978 pumping levels, twice 1978 pumping levels, and five times 1978 pumping levels. The water levels due to these conditions are shown in plan and in cross sections of the aquifer. The effect of zero recharge to the aquifer is next demonstrated for the pumping levels existing during 1978. The final run shows how long the aquifer takes to reach steady state when the pumping rate is increased from the 1978 pumping level to twice that value. The program can be used for numerous other studies for management and planning purposes. 相似文献
108.
109.
Robert N. Havis Carlos V. Alonso John G. King Russell F. Thurow 《Journal of the American Water Resources Association》1993,29(3):435-444
ABSTRACT: A simulation model [Salmonid Spawning Analysis Model (SSAM)] was developed as a management tool to evaluate the relative impacts of stream sediment load and water temperature on salmonid egg survival. The model is useful for estimating acceptable sediment loads to spawning habitat that may result from upland development, such as logging and agriculture. Software in common use in the USA were adapted for use in gravel bedded rivers and linked to simulate water temperature (the USFWS Instream Water Temperature, SNTEMP model) and water and sediment routing (the USAE Scour and Deposition in Rivers and Reservoirs, HEC-6 model, version 3.2). These models drive the redd (spawning nest) model (the USDA-ABS Sediment Intrusion Dissolved Oxygen SIDO model) which simulates sediment intrusion and dissolved oxygen concentration in the redd environment. The SSAM model predictions of dissolved oxygen and water temperature compared favorably with field data from artificial redds containing hatchery chinook salmon eggs. 相似文献
110.
本文在总结长江口地区现状盐水入侵时空变化规律的基础上,着重分析了在未来海平面上升、长江东线南水北调和三峡水利枢纽工程以及长江口北支综合整治等因素影响下,南支河段盐水入侵强度的变化趋势。 相似文献