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131.
Plant communities in relation to flooding and soil contamination in a lowland Rhine River floodplain
Schipper AM Lotterman K Leuven RS Ragas AM de Kroon H Hendriks AJ 《Environmental pollution (Barking, Essex : 1987)》2011,159(1):182-189
Using canonical correspondence analysis (CCA), relationships were investigated between plant species composition and flooding characteristics, heavy metal contamination and soil properties in a lowland floodplain of the Rhine River. Floodplain elevation and yearly average flooding duration turned out to be more important for explaining variation in plant species composition than soil heavy metal contamination. Nevertheless, plant species richness and diversity showed a significant decrease with the level of contamination. As single heavy metal concentrations seemed mostly too low for causing phytotoxic effects in plants, this trend is possibly explained by additive effects of multiple contaminants or by the concomitant influences of contamination and non-chemical stressors like flooding. These results suggest that impacts of soil contamination on plants in floodplains could be larger than expected from mere soil concentrations. In general, these findings emphasize the relevance of analyzing effects of toxic substances in concert with the effects of other relevant stressors. 相似文献
132.
Concentration of trace elements in feathers of three Antarctic penguins: Geographical and interspecific differences 总被引:1,自引:0,他引:1
Silvia JerezMiguel Motas María José PalaciosFrancisco Valera José Javier Cuervo Andrés Barbosa 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2412-2419
Antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. Concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were determinated by ICP-MS in feathers (n = 207 individuals) of gentoo, chinstrap and Adélie penguin collected in 8 locations throughout the Antarctic Peninsula (2006-2007). The highest levels of several elements were found in samples from King George Island (8.08, 20.29 and 1.76 μg g−1 dw for Cr, Cu and Pb, respectively) and Deception Island (203.13, 3.26 and 164.26 μg g−1 dw for Al, Mn and Fe, respectively), where probably human activities and large-scale transport of pollutants contribute to increase metal levels. Concentrations of Cr, Mn, Cu, Se or Pb, which are similar to others found in different regions of the world, show that some areas in Antarctica are not utterly pristine. 相似文献
133.
Salinity increases mobility of heavy metals in soils 总被引:11,自引:0,他引:11
The effect of salinity induced by CaCl2, MgCl2, NaCl and Na2SO4 on the mobility of Cu, Cd, Pb and Zn was studied. An increase of ionic strength by any salts promoted a higher release of Cd than the others metals. When CaCl2 and NaCl were applied, Cd and Pb showed the highest degree of mobilization. When MgCl2 was applied, Cd and Cu were mobilized the most. Finally, an increase of Na2SO4 also promoted the strongest mobilization of Cd and Cu.As the total heavy metal content was higher, the percentage of Pb and Cu released upon salinization decreased, indicating that these metals are strongly bound to soil constituents. An increase of carbonates in the soil promoted a higher release of Pb for all used salts and for Zn when MgCl2 and NaCl were used. This indicates that Pb and Zn are adsorbed on the surface of carbonate crystals. An increase of fine particles promoted a decrease of percentage of released Cd for all salts, indicating that Cd is strongly retained in the fine fractions.The main mechanism regulating Pb and Cd mobility was competition with Ca2+ for sorption sites followed for metal chloro-complexation, association between the Cd/Pb-sulfates and competition with Mg2+. The main mechanism regulating Cu mobility was the formation of Cu-sulfate, followed by competition with cations (Mg > Ca) and chloride. For Zn, competition with Ca2+ for sorption sites was the most important process for its mobility; followed by Zn-sulfate association and, finally, chloride and competition with Mg with the same effect. 相似文献
134.
Comparison of EDTA-enhanced phytoextraction and phytostabilisation strategies with Lolium perenne on a heavy metal contaminated soil 总被引:2,自引:0,他引:2
Phytoremediation is a promising and cost-effective strategy to manage heavy metal polluted sites. In this experiment, we compared simultaneously phytoextraction and phytostabilisation techniques on a Cd and Zn contaminated soil, through monitoring of plant accumulation and leaching. Lolium perenne plants were cultivated for 2 months under controlled environmental conditions in a 27.6 dm3-pot experiment allowing the collect of leachates. The heavy metal phytoextraction was promoted by adding Na-EDTA (0.5 g kg−1 of soil) in watering solution. Phytostabilisation was assessed by mixing soil with steel shots (1%) before L. perenne sowing. Presence of plants exacerbated heavy metal leaching, by improving soil hydraulic conductivity. Use of EDTA for phytoextraction led to higher concentration of heavy metal in shoots. However, this higher heavy metal extraction was insufficient to satisfactory reduce the heavy metal content in soil, and led to important heavy metal leaching induced by EDTA. On the other hand, addition of steel shots efficiently decreased both Cd and Zn mobility, according to 0.01 M CaCl2 extraction, and leaching. However, improvement of growth conditions by steel shots led to higher heavy metal mass in shoot tissues. Therefore, soil heavy metal mobility and plant metal uptake are not systematically positively correlated. 相似文献
135.
以绿色经济和循环经济的重大需求为背景,系统阐述了废钢加工装备的现状与发展,详细介绍了废钢加工装备的种类与用途,分析并总结了废钢加工装备的应用现状,指出了废钢加工装备以及废钢加工行业的发展方向。 相似文献
136.
某武器放线装置振动夹具的设计 总被引:1,自引:0,他引:1
振动试验是武器装备环境与可靠性试验最关键的项目之一,而振动试验专用夹具设计对试验结果起着决定性影响.叙述了振动试验用夹具的设计要求、原则,对某武器线导放线装置振动试验夹具的设计方法、步骤及使用效果进行了阐述. 相似文献
137.
人-机-环境系统是把人、机、环境作为武器系统中的要素,从总体角度对武器装备进行全面规划和控制.人-机-环境系统在武器装备研制中的应用,将改变以往武器装备分散、孤立的研究局面,它把武器装备研制推向一个新阶段.综述了武器装备研制的不同阶段应用人-机-环境系统的基本思路. 相似文献
138.
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140.
Regasification plants have become an emerging risk because their numbers are increasing and concern from the general population towards these systems has grown. Consequently, there is increased interest in investigating the effect of mitigation measures to limit the impact of large accidents on the population living close to the plant. Among the various possible mitigation measures, physical barriers present several advantages; however, it is known that the necessary barrier height can became impracticably large to be effective in mitigating the consequences of a large LNG release. Therefore, computational fluid dynamics models were used in this work to analyze the performance of mitigation barriers with different shapes to investigate the possibility of increasing mitigation barrier efficiency by simply changing the main geometrical characteristics of the barrier such as roughness, battlements, or even holes. 相似文献