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The relative concentrations of hydrogen sulphide and sulphur dioxide in volcanic gases cannot be explained simply by the temperatures and pressures, and appear as the result of the influence of different natural factors. SO2 is directly related to magma degassing, while H2S can be produced by the reaction of acidic solutions on dispersed sulphide minerals.
As long as these inputs to the surface environment are of moderate extent, then readjustment of redox conditions to an equilibrium situation will occur; a permanent disequilibrium will result in increased contributions of any component.
A wide spectrum of trace elements is normally associated with the presence of sulphur compounds in volcanic areas; their importance can be estimated for any system on the basis of the quantitative relationship between the oxidized and the reduced sulphur species. Extensive polluting effects can be produced by a continuous flow from a deep magmatic source, while minor consequences are associated with a re-circulation in the surface environment of heavy metals from previous volcanic activities. 相似文献
As long as these inputs to the surface environment are of moderate extent, then readjustment of redox conditions to an equilibrium situation will occur; a permanent disequilibrium will result in increased contributions of any component.
A wide spectrum of trace elements is normally associated with the presence of sulphur compounds in volcanic areas; their importance can be estimated for any system on the basis of the quantitative relationship between the oxidized and the reduced sulphur species. Extensive polluting effects can be produced by a continuous flow from a deep magmatic source, while minor consequences are associated with a re-circulation in the surface environment of heavy metals from previous volcanic activities. 相似文献
63.
Chemical composition of volatiles emitted from fresh mouse carcasses (laboratory mice, Mus musculus) was studied using solid sample injection technique (solid-phase micro-extraction), two-dimensional gas chromatography with
time of flight mass spectrometric detection and gas chromatography with electroantennographic detection. Electroantennography
(EAG) and laboratory olfactometric behavioural observations were used to study the antennal sensitivity to identified infochemicals
and their attractiveness for burying beetles Nicrophorus vespillo and Nicrophorus vespilloides (Silphidae: Nicrophorinae). Chemical analysis showed that immediately after death, emitted volatiles did not differ from
those emitted by a living organism. However, in the course of time, sulphur-containing chemicals, specifically methanethiol,
methyl thiolacetate, dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide appear. EAG measurements revealed antennal
sensitivity to these compounds. Behavioural tests in laboratory olfactometer showed that dimethyl sulphide, dimethyl disulphide
and dimethyl trisulphide are highly attractive to both studied species. The data suggest that sulphur-containing chemicals
are involved in mediating the fresh carcass attractiveness for N. vespillo and N. vespilloides. 相似文献
64.
González V García I del Moral F de Haro S Sánchez JA Simón M 《Journal of environmental management》2011,92(6):1509-1519
Thirty-five soil samples were taken from unconfined mine waste, stream sediments, and surfaces unoccupied by mining and presumably unaffected by it, in a sulphur-mining zone surrounded by carbonate material and characterized by a semi-arid climate with short torrential storms. These samples were analysed and the results compared to estimate the spread of pollution in the landscape and to assess potential environmental risk. The mean concentrations of S, Zn, Cd, Pb, and As in mine waste were between 3.5-fold (As) and 50-fold (S) greater than unaffected soils. Oxidation of S led to a sharp drop in pH, strong weathering of minerals, and solubilisation of the constituent elements, forming a toxic acidic mine drainage with highly concentrated pollutants that were discharged into the drainage channels. Successive acid mine drainage into the soil on the valley floor spreads acidification and pollution downstream. The high carbonate content in surrounding soils played an important role in the increase of the pH and precipitation of S, Pb, and Al of the affected soils. Meanwhile, high mobility of Zn, Cd and As under basic conditions and a low Fe concentration explain the broad spread of these elements, as high concentrations were detected in soil more than 2000 m from the source. Only the soil solutions from near the waste dump (first 500 m) were highly phytotoxic, and moderately phytotoxic from 500 to 1500 m away. The concentration of pollutants in the leachates was clearly higher than in soil solutions, even in the soils located over 2000 m from the source, implying that the size of the polluted area will increase with time. 相似文献
65.
"十一五"规划纲要中明确提出了主要污染物排放总量减少10%的战略目标,合理进行SO2削减是实现这一目标的基础。运用基于生产前沿的DEA模型计算了我国东部地区11个省、直辖市1990到2007年18年间的SO2有效削减百分比。计算结果显示,经济越发达、产业结构越优化的地区,该值越小。1990~2007年间的平均SO2有效削减百分比上海、广东、福建、海南最小,一直为0。北京、天津、浙江、江苏较低,平均SO2有效削减百分比分别为13.83%、15.31%、18.36%、21.14%,而河北、山东最高,分别为39.81%、32.00%,应该加强这些地区的SO2削减,采取措施提高SO2排放效率。 相似文献
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研究了大气自动监测系统中标准气、校准气以及零空气的流量大小引起仪器示值误差及时校准曲线质量的影响,提出了重点控制标气流量是减小仪器示值误差的关键,从而解决了低浓度校准点仪器示值偏低、误差大及校准曲线截距大的技术难点,提高了大气自动监测中多点校准质量和监测结果的准确性. 相似文献