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271.
A comprehensive technological copper cycle treating a series of life stages (mining and processing, fabrication, utilization, and end of life) has been constructed for sixteen countries on the European continent for the year 1994. In this paper we draw on that information to present country-level copper cycles for a sampling of the countries. We then compare the countries on the basis of their relative and absolute copper production, import/export, usage, recycling, and losses to the environment, and go on to produce per capita assessments of flow and stock changes. Among the results of particular interest are: (1) country-level copper budgets possess features often different from the continental budgets of which they are a part. For example, Europe extracted only slightly more copper from mines than it deposited in landfills, while the mine to landfill flow ratio was about 11:1 in Poland and near zero in the United Kingdom; (2) Germany led all other countries in the group of sixteen in the absolute magnitude of every major copper flow (production, import, export, consumption, and waste generation, and in per capita flows of copper entering use and waste management), while the Benelux countries led all others in per capita flows for all other categories; (3) citizens of essentially all the countries discarded 1–3 kg Cu/year, mostly in obsolete electronics and end-of-life vehicles.  相似文献   
272.
Concentrations of Pb, Zn, Cd, Cu,Cr, Co and Ni were determined in topsoil obtained from vicinities of auto-repair workshops, gas-stations and motor-parks in Ibadan, Nigeria. The levels were elevated above background concentrations in control sites. Lead and copper were the most significant contaminants, and the degree of contamination was highest in auto-repair workshops. Factors of accumulation for Pb and Cu were: auto-repair workshops: Pb - 95.8, Cu - 117; gas stations: Pb - 46.6, Cu - 33.5; motor-parks: Pb - 31.6, Cu - 16.8. For Zn, Cd, Cr, Co and Ni, the factors of accumulation were much lower and did not vary much among the three study areas. Average values for all locations were: Zn - 5.2, Cd - 4.4, Cr - 3.7, Co - 1.5, Ni - 1.7. Improper disposal of waste lubricants is the likely source of high copper contamination.  相似文献   
273.
● Cu addition enhances CH3OH oxidation and alleviates its inhibitory effect on SCR. ● Cu addition improves the activation of SCR reactants in the presence of methanol. ● Damaged structure by more Cu addition decreases specific surface area and acidity. ● Excessive Cu addition would lead to the narrowing of SCR temperature window. Simultaneously removal of NOx and VOCs over NH3-SCR catalysts have attracted lots of attention recently. However, the presence of VOCs would have negative effect on deNOx efficiency especially at low temperature. In this study, copper modification onto Sb0.5CeZr2Ox (SCZ) catalyst were performed to enhance the catalytic performance for simultaneous control of NOx and methanol. It was obtained that copper addition could improve the low-temperature activity of both NOx conversion and methanol oxidation, where the optimal catalyst (Cu0.05SCZ) exhibited a deNOx activity of 96% and a mineralization rate of 97% at 250 °C, which are around 10% higher than that of Cu free sample. The characterization results showed that copper addition could obviously enhance the redox capacity of the catalysts. As such, the inhibition effect of methanol incomplete oxidation on NO adsorption and NH3 activation were then lessened and the conversion of surface formamide species were also accelerated, resulting in the rising of NOx conversion at low temperature. However, excessive copper addition would damage the Sb-Ce-Zr oxides solid solution structure owing to Cu-Ce strong interactions, decreasing the surface area and acidity. Meanwhile, due to easier over-oxidation of NH3 with more Cu addition, the temperature window for NOx conversion would become quite narrow. These findings could provide useful guidelines for the synergistic removal of VOCs over SCR catalyst in real application.  相似文献   
274.
Copper flotation waste from copper production using a pyrometallurgical process contains toxic metals such as Cu, Zn, Co and Pb. Because of the presence of trace amounts of these highly toxic metals, copper flotation waste contributes to environmental pollution. In this study, the leaching characteristics of copper flotation waste from the Black Sea Copper Works in Samsun, Turkey have been investigated before and after vitrification. Samples obtained from the factory were subjected to toxicity tests such as the extraction procedure toxicity test (EP Tox), the toxicity characteristic leaching procedure (TCLP) and the "method A" extraction procedure of the American Society of Testing and Materials. The leaching tests showed that the content of some elements in the waste before vitrification exceed the regulatory limits and cannot be disposed of in the present form. Therefore, a stabilization or inertization treatment is necessary prior to disposal. Vitrification was found to stabilize heavy metals in the copper flotation waste successfully and leaching of these metals was largely reduced. Therefore, vitrification can be an acceptable method for disposal of copper flotation waste.  相似文献   
275.
Stormwater wetlands are created to retain water from storms and snow melt to reduce sediment, nutrient, and contaminant pollution of natural waterways in metropolitan areas. However, they are often a source of attractive habitat to wetland-associated wildlife. In this study of 12 stormwater wetlands and a larger, older reference site, elevated concentrations of zinc and copper were found in sediments and carcasses of 8-day-old red-winged blackbird (Agelaius phoeniceus) nestlings inhabiting stormwater sites. Although nesting success in the stormwater wetlands was comparable to national averages, sediment zinc concentrations correlated with clutch size, hatching success, fledgling success, and Mayfield nest success, suggesting that the nestlings may have been stressed and impaired by elevated zinc. This stress may have been direct on the nestlings or indirect through effects on the availability of food organisms.Published online  相似文献   
276.
开发玉龙铜矿的经济评价   总被引:1,自引:0,他引:1  
本文分析了开发玉龙铜矿床的优势条件.对玉龙铜矿的开发进行了效益评估,并提出了可持续开发对策.  相似文献   
277.
We present here a copper speciation model that accounts for the long-term (‘coastal-acidification’) and short-term (daily and seasonal variation) variability in water pH and water temperature. The developed model is applied to a sub-tropical estuary (Moreton Bay, Australia) at a one hundred year time scale so that outputs are consistent with climate change projections. The model predicts that the mean cupric ion concentration (Cu2+) in the estuary will increase by 115% over the next 100 years as a result of the projected decrease in pH and increase in water temperature. Through calibration, the estimated concentration of copper-complexing dissolved organic matter (DOM) in the estuary is found to be 22.5 nM. An increase in the concentration of Cu2+, which is the most toxic and bioavailable form of copper, has implications for ecosystem health and may have a negative effect on the detoxifying capacity of DOM. Models that provide a framework for coupling biological, chemical and physical processes are important for providing a holistic perspective of coastal systems, especially for better understanding a system within the context of climatic and non-climatic drivers.  相似文献   
278.
Boojar MM  Goodarzi F 《Chemosphere》2007,67(11):2138-2147
This study was undertaken to identify the strategies and the status of antioxidant enzyme activities involved in three plant species tolerance against Cu-toxicity in copper mine. The following methods were used for evaluations in three wild type species; Datura stramonium, Malva sylvestris and Chenopodium ambrosioides. The level of chlorophyll and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) by spectrometry, malondialdehyde (MDA) and dityrosine by HPLC and the levels of Cu in tissues and soils by atomic absorption spectrometry (AAS).

Analysis showed that total and available copper were at toxic levels for plants growing on contaminated soil (zone 1). However, there were not any visual and conspicuous symptoms of Cu toxicity in plant species. Among three species, excess copper was transferred only into the D. stramonium and C. ambrosioides tissues. The C. ambrosioides accumulated Cu in roots and then in leaves, in which the leaves chloroplasts stored Cu around two times of vacuoles. In D. stramonium most of Cu was accumulated in leaves in which the storage rate in vacuoles and chloroplasts were 42% and 8%, respectively. In zone 1, the chlorophyll levels increased significantly in leaves of C. ambrosioides with respect to the same plant growing on uncontaminated soil (zone 2). There was insignificant decrease in chlorophyll content of D. stramonium leaves, collected from zone 1 with respect to zone 2. The D. stramonium and C. ambrosioides in zone 1, both revealed significant increase in their tissues antioxidant enzyme activities in comparison with the same samples of zone 2. There was significant elevation in oxidative damage biomarkers; MDA and dityrosine, when the aerial parts of D. stramonium in zone 1 were compared with the same parts of zone 2.

We concluded that there were different tolerance strategies in studied plant species that protected them against copper toxicity. In M. sylvestris, exclusion of Cu from the roots or its stabilization in the soil restricted Cu toxicity effects. On the other hand D. stramonium and C. ambrosioides, elevated their antioxidative enzyme activities in response to cu-toxicity. In addition, the species D. stramonium accumulated excess of Cu in leaves vacuoles.  相似文献   

279.
杨红飞  王友保  李建龙 《生态环境》2011,(10):1470-1477
通过盆栽试验,系统研究了Cu、Zn重金属污染对油菜(Brassica chinensis L.)生长、SOD保护酶活性、脯氨酸、可溶性糖及Cu、Zn在油菜体内吸收富集的影响。结果表明:Cu、Zn污染对油菜生物量和生理生化指标(SOD保护酶活性、脯氨酸和可溶性糖)均有影响。随着Cu、Zn质量分数的升高,植株干物重和SOD保护酶活性表现为先增后降;当Cu质量分数达到1 000 mg?kg-1时,油菜干物重和SOD酶活性分别比对照下降36.79%、66.67%;当Zn质量分数达到3 000 mg?kg-1时,油菜干物重和SOD酶活性分别比对照下降55.21%、82.05%。Cu污染下,油菜叶片脯氨酸质量分数逐渐下降,总可溶性糖质量分数表现为先增后降;Zn污染下,脯氨酸和总可溶性糖质量分数均表现为先增后降。Cu、Zn污染使油菜幼苗叶片及根中的Cu、Zn质量分数明显增加,根部的积累尤其明显。当Cu处理为1 000 mg?kg-1时,油菜茎叶和根中质量分数分别为57.6、424.162 mg?kg-1;当Zn处理为1 000 mg?kg-1时,油菜茎叶和根中质量分数分别为240、608.54 mg?kg-1。与Zn相比,Cu主要积累在油菜的根部,向茎叶迁移累积的量很少,并且随着添加质量分数的增加,茎叶吸收Cu的量变化不大。总之,重金属Zn相对于Cu更容易积累于油菜的地上部分,从而更易进入食物链,它们在油菜体内富集都对其生理生化和营养产生了明显毒害作用。  相似文献   
280.
The common and widespread copper contamination in marine coastal environments make toxicity data necessary to assess the aquatic hazard and risk of this metal.  相似文献   
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