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922.
923.
924.
山阴水砷中毒区地下水砷的富集因素分析 总被引:27,自引:5,他引:22
通过对山阴地区66个地下水样中常量元素、微量元素及有机物分析,研究了山阴高砷地下水的水化学特性并在此基础上,结合该地区含水层沉积物矿物分析,探讨了地下水中砷富集的影响因素.结果表明,山阴地下水平均pH为8.09,磷酸根含量为0.71mg/L,溶解性有机物含量为5.14 mg/L,以及地下水处于还原环境.高pH值、高磷酸根含量及还原环境不利于含水介质对以阴离子形式存在的砷的吸附,高溶解性有机物含量则增加了砷的活性这些因素促使了含水介质中砷的解吸和迁移. 相似文献
925.
Shufang WU Pute WU Hao FENG G. P. Merkley 《Frontiers of Environmental Science & Engineering》2011,5(1):76-83
An evaluation of the interactions between vegetation, overland and soil erosion can provide valuable insight for the conservation of soil and water. An experiment was conducted to study water infiltration, runoff generation process, rate of sediment erosion, and hydrodynamic characteristics of overland flow from a sloping hillside with different draw-off discharges from alfalfa and control plots with 20° slope. The effect of alfalfa on runoff and sediment transport reduction was quantitatively analyzed. Alfalfa was discussed for its ability to reduce the overland flow scouring force or change the runoff movement. Compared to the bare-soil plots, alfalfa plots generated a 1.77 times increase in infiltration rate. Furthermore, the down-slope water infiltration rate for the bare soil plots was higher than in the up-slope, while the opposite was found in the alfalfa plots. In addition, alfalfa had a significant effect on runoff and sediment yield. In comparison to the control, the runoff coefficient and sediment transportation rate decreased by 28.3% and 78.4% in the grass slope, respectively. The runoff generated from the alfalfa and bare-soil plots had similar trends with an initial increase and subsequent leveling to a steady-state rate. The transport of sediment reduced with time as a consequence of the depletion of loose surface materials. The maximum sediment concentration was recorded within the first few minutes of each event. The alfalfa plots had subcritical flow while the bare-soil plots had supercritical flow, which indicate that the capability of the alfalfa slope for resisting soil erosion and sediment movement was greater than for bare soil plots. Moreover, the flow resistance coefficient and roughness coefficient for the alfalfa plots were both higher than for the bare-soil plots, which indicate that overland flow in alfalfa plots had retarded and was blocked, and the flow energy along the runoff path had gradually dissipated. Finally, the ability to erode and transport sediment had decreased. 相似文献
926.
927.
通过电炉铜与转炉铜能耗对比,突显了电炉钢的节能与环保优势,同时介绍了国内外电炉钢应用现状。随着社会工业化的发展所带来的钢铁积蓄量的增加,以及电炉钢技术的不断完善和发展,加之迎合国家低碳经济政策的实施,国内电炉钢发展具有广阔前景。 相似文献
928.
Hydrocarbon emissions from a diesel invert mud residue (DIMR) were monitored while the hydrocarbons were being biodegraded in a solid‐phase bioreactor. Five to twenty percent of the reduction in diesel hydrocarbons was attributed to evaporation depending on the treatment, i.e. homogenization, cultivation, and aeration. Most of these volatile hydrocarbons were linear C8 — C12 alkanes and one‐ring aromatics. Of the treatments aeration had the largest effect on emissions; forced air through the bottom of the bioreactor cells increased emissions by three times over that of the non‐aerated cells. Cultivation increased hydrocarbon emission concentration as much as twofold over the pre‐cultivation value, however, emissions returned to the original levels within 12 hours. Homogenization had the least effect of all treatments. Diurnally, the emission rate was 40% higher in late afternoon than at midnight; the cause of which was probably atmospheric fluctuations such as temperature and solar radiation. The effects of daily atmospheric fluctuations were empirically modeled and taken into account for determining the total volume of emissions. 相似文献
929.
930.
利用彗星实验检测渤海区主要入海河流遗传毒性.以虾虎鱼为受试生物,暂养在河口水样中,染毒48h,取外周血细胞,运用彗星实验检测外周血细胞内DNA损伤程度,以尾相(TM)作为DNA损伤程度指标,并据此评估入海河流邻近海域遗传毒性风险.实验结果表明,入海河流中的特征污染物可导致虾虎鱼外周血细胞的DNA损伤,且损伤程度可以通过彗星实验定量分析,同时该试验方法操作简便、快速、灵敏度高,能够反映出多种污染因子的综合致毒能力.因此,通过彗星实验建立实验室检测入海河流遗传毒性方法具有可行行和创新性. 相似文献