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841.
The harmful effect of manmade particles on natural processes and human health is documented by a large number of studies showing a positive correlation between particulate matter (PM) concentration and health effects. Diminution of this health risk necessitates among others the precise knowledge of the particle sources, their physical and chemical properties and their dissemination in the environment. Pb isotope ratios have been successfully used during the past decades as tracers of anthropogenic Pb disseminated in the biosphere. Here we show that tree bark biomonitoring with lead (Pb), strontium (Sr) and neodymium (Nd) isotope ratios as tracers allow a thorough analysis of the impacts of industrial and other anthropogenic emissions on the urban environment. This is the first comprehensive multi-isotope tracer study of atmospheric pollution in an urban environment allowing to identify and to integrate the different plume paths of emissions in a digital map system. This innovative approach might become an important tool for environmental management and policy-making processes dealing especially with risks and surveillance of air quality in the urban environment. 相似文献
842.
The mineral resources exploitation stage and the economic growth rate are various in different regions of Xinjiang Autonomous region. Using the method of location quotient, this paper identifies and classifies the intensive regions of three types of mineral resources, known as coal, oil and natural gas, respectively. The intensive regions of economic growth were also identified, according to the rate of per capita GDP growth at prefecture, autonomous prefecture and city. The relationships between different mineral resources and economic growth are different, for example, the relationship between economic growth and coal resource is positive, while the relationship between economic growth and oil resource, or natural gas resource is negative. This study empirically examines the effects of natural resources on economic growth of Xinjiang. The results show that whilst natural resources have a positive impact on growth, and can make a negative impact on growth through the transmission channels, such as investment, manufacture, human capital, and scientific and technologic innovation. Moreover, it studies the transmission channels, that is, the effect of natural resources on the other explanatory variables, and calculates the indirect effect of natural resources on growth for each transmission channel, and comprehensive effects of natural resources on growth. The calculated result of comprehensive effects indicates that the positive direct effects of natural resources on growth are shown to outweigh the negative indirect effect of Xinjiang autonomous region. 相似文献
843.
Effect of surfactants, dispersion and temperature on solubility and biodegradation of phenanthrene in aqueous media 总被引:1,自引:0,他引:1
Pantsyrnaya T Blanchard F Delaunay S Goergen JL Guédon E Guseva E Boudrant J 《Chemosphere》2011,83(1):29-33
In the present study surfactant addition with the help of either a mechanical dispersion or a thermal treatment was applied in order to increase the solubility and the bioavailability of phenanthrene in aqueous media, and therefore to promote its biodegradation. Among four tested surfactants (Tween 80, Brij 30, sodium dodecyl sulphate and rhamnolipids), Brij 30 (0.5 gL(-1)) showed the best results allowing us to attain about 20 mgL(-1) of soluble phenanthrene. An additional thermal treatment at 60°C for 24h, 200 rpm permitted to increase the solubility of phenanthrene in the presence of Brij 30 (0.5 gL(-1)) to about 30 mgL(-1). Higher dispersions of phenanthrene particles as well as the reduction of their size were obtained using Ultra-Turrax and French press. The biodegradation of phenanthrene by Pseudomonas putida was then investigated. The reduction of size of phenanthrene particles by mechanical dispersion did not influence its biodegradation, suggesting that P. putida consumed only soluble phenanthrene. The addition of Brij 30 (0.5 gL(-1)) permitted to obtain more phenanthrene metabolized. The use of Brij 30 coupled with a transitory heating of phenanthrene-containing medium at 60°C led to an even more complete biodegradation. This might be a promising way to enhance biodegradation of PAHs. 相似文献
844.
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846.
The availability of the five chemical fractions, i.e., exchangeable (F1), carbonate-bound (F2), Fe/Mn oxide-combined (F3), organic matter-complexed (F4), residual (F5), of three heavy metals (Cu, Zn, and Cd), has been investigated by way of a sequential extraction technique based on the characteristics of the coastal soils developed from alluvial deposits, in order to analyze the relationship of the formation and development of coastal soils. The results showed that F1 and F5 of Cu, Zn, and Cd accounted dominantly for 9.11%, 2.74%, and 20.37%, and for 39.49%, 45.18%, and 32.43% of total heavy metal contents, respectively, indicating the order of availability and mobility: Cd > Cu > Zn. F2, F3, and F4 of HMs also featured prominently in the behaviors of heavy metals. Random measurement errors from both sampling and analysis were demonstrated by SAX to be well within the control target of 20% and, therefore, of no impediment to the geochemical interpretation of the data. Significant positive correlation was found between certain fractions of heavy metals and some soil properties. Some negative correlation was also found. The findings were helpful to the soil remediation, fertility adjustment, and plant cultivation. 相似文献
847.
Impact of woodchip biochar amendment on the sorption and dissipation of pesticide acetamiprid in agricultural soils 总被引:4,自引:0,他引:4
Pyrolysis of vegetative biomass into biochar and application of the more stable form of carbon to soil have been shown to be effective in reducing the emission of greenhouse gases, improving soil fertility, and sequestering soil contaminants. However, there is still lack of information about the impact of biochar amendment in agricultural soils on the sorption and environmental fate of pesticides. In this study, we investigated the sorption and dissipation of a neonicotinoid insecticide acetamiprid in three typical Chinese agricultural soils, which were amended by a red gum wood (Eucalyptus spp.) derived biochar. Our results showed that the amendment of biochar (0.5% (w/w)) to the soils could significantly increase the sorption of acetamiprid, but the magnitudes of enhancement were varied. Contributions of 0.5% newly-added biochar to the overall sorption of acetamiprid were 52.3%, 27.4% and 11.6% for red soil, paddy soil and black soil, respectively. The dissipation of acetamiprid in soils amended with biochar was retarded compared to that in soils without biochar amendment. Similar to the sorption experiment, in soil with higher content of organic matter, the retardation of biochar on the dissipation of acetamiprid was lower than that with lower content of organic matter. The different effects of biochar in agricultural soils may attribute to the interaction of soil components with biochar, which would block the pore or compete for binding site of biochar. Aging effect of biochar application in agricultural soils and field experiments need to be further investigated. 相似文献
848.
Gu HH Qiu H Tian T Zhan SS Deng TH Chaney RL Wang SZ Tang YT Morel JL Qiu RL 《Chemosphere》2011,83(9):1234-1240
The mechanisms of stabilization by silicon-rich amendments of cadmium, zinc, copper and lead in a multi-metal contaminated acidic soil and the mitigation of metal accumulation in rice were investigated in this study. The results from a pot experiment indicated that the application of fly ash (20 and 40 g kg−1) and steel slag (3 and 6 g kg−1) increased soil pH from 4.0 to 5.0-6.4, decreased the phytoavailability of heavy metals by at least 60%, and further suppressed metal uptake by rice. Diffusion gradient in thin-film measurement showed the heavy metal diffusion fluxes from soil to solution decreased by greater than 84% after remediation. X-ray diffraction analysis indicated the mobile metals were mainly deposited as their silicates, phosphates and hydroxides in amended treatments. Moreover, it was found metal translocation from stem to leaf was dramatically restrained by adding amendments, which might be due to the increase of silicon concentration and co-precipitation with heavy metals in stem. Finally, a field experiment showed the trace element concentrations in polished rice treated with amendments complied with the food safety standards of China. These results demonstrated fly ash and steel slag could be effective in mitigating heavy metal accumulation in rice grown on multi-metal contaminated acidic soils. 相似文献
849.
850.