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31.
Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.  相似文献   
32.
The increasing volume of CO2 embodiment in international trade adds a layer of complexity to environmental policies and has raised arguments on the traditional production based responsibility for CO2 emissions. In order to help understand the quantity of CO2 embodiment in trade and its policy implications, this paper gives observations to recently emerging literatures that quantitatively discuss CO2 embodiment in trade. The analytical approaches share the principle of using input and output modeling but vary dramatically in study boundary and estimation accuracy. The calculations can be roughly categorized into three types: direct quantification of CO2 embodiments in multiregional trade, direct quantification of CO2 embodiment in bilateral trade, and indirect analysis by comparing the scenarios with or without trade. The practical estimations strongly rely on trade partner selection and data availability. An obvious imbalance of net CO2 embodiment in the commodity trade between major developed countries and developing economies as a whole was confirmed by these literatures. Carbon taxes and other possible limitations on CO2 emissions have been addressed. The consistency across the calculations could be enhanced by systematic analyses in more detail to convince the international community to take binding commitments for the reduction of global CO2 emissions.  相似文献   
33.
根据断层形变剖面资料分析泾阳口镇-关山断裂活动状况   总被引:2,自引:0,他引:2  
首先分析泾阳地震台1986~2005年跨口镇一关山断层定点形变观测资料,指出形变剖面各点的运动特征:1995年前泾阳台N1A测线资料基本上呈线性变化,1995~1997年该测线形变资料呈现较大的波动性异常,1998年1月5日陕西泾阳发生4.8级地震,靠近断层的点位发生了阶跃式变化,之后各点位运动渐趋于平缓.其后结合断层位错模型引起的地表形变特征,分析得出该形变变化主要由地裂和断裂活动共同引起;不考虑地震引起的异常时段,分析1986~1994以及1999~2005形变年变化量,可看出变化趋势基本一致;最后利用1986~1994形变速率进行断层蠕滑段或地裂速率及深度反演.从反演结果可以看出,基准点N1比较稳定,3号点附近的地裂较浅,底部几十米,以垂直下滑为主,兼有张裂活动;5、6号点之间的断层活动深度在1 km左右.该断层上盘仍在下降.  相似文献   
34.
2008年汶川8.0级地震发生以来,极震区泥石流爆发频率有增无减且规模越来越大,破坏性越来越强,严重威胁灾区人民生命财产安全。对比采取现场勘查、遥感图像分析、历史资料对比分析等方法,分析了极震区泥石流动力特征受地形、地层、物源等因素的影响,特别是泥石流爆发过程中深侵蚀和溃决对泥石流动力特征的影响。针对四川安县高川乡流域泥石流沟的调查和分析,建立泥石流流量-冲刷模型,分析了常规地区泥石流峰值流量与极震区泥石流峰值流量差别,推导出极震区峰值流量及冲刷深度定量计算公式。通过实例分析,理论与实际具有较好的一致性,对极震区泥石流动力参数计算具有较好适用性和有效性。  相似文献   
35.
In order to investigate the bioremedial potential of humic deposit (leonardite), the effects of the treatments of leonardite and a commercial bioaugmentation agent on the degradation of a variety of petroleum hydrocarbons (C13–C31) and soil enzyme activities (urease acid-alkaline phosphatase and dehydrogenase) were tested within a soil incubation experiment lasting 120 days. Experimentally crude-oil-contaminated soil (2.5%) was regulated to a C:N:P ratio (100:15:1; Oilcon), amended with 5% of leonardite and regulated to the same C:N:P ratio (Oilcon-L) or mixed with a commercial bioaugmentation product (Oilcon-B), respectively. In the short period of incubation (60 days), Oilcon and Oilcon-B treatments showed higher hydrocarbon degradations, whereas Oilcon-L showed higher hydrocarbon degradation over Oilcon and Oilcon-B treatments in the long-term (120 days). Applying contaminated soil with leonardite increased urease (LSD, 4.978, *P?<?0.05) and dehydrogenase (LSD, 0.660, *P?<?0.05) activities. However, acid and alkaline phosphatase activities showed no certain inclination between different treatments. Dehydrogenase seemed to be more related to hydrocarbon degradation process. Overall results showed that leonardite enhanced biodegradation of petroleum hydrocarbons and also stimulated soil ecological quality measured as soil enzyme activities.  相似文献   
36.
吕太  张雄  杨博然 《环境工程学报》2017,11(3):1729-1736
中国环境保护部和国家质量监督检验检疫总局联合发布了GB 13223-2014,要求火电厂烟尘排放限值应小于30 mg·m-3,老式单一的电除尘器已经很难达到环保要求。以某电厂为例,对电除尘器入口处接低低温省煤器和将原静电除尘器改造为电袋复合除尘器的2种优化改造方案进行了模拟,并对2种方案的经济性进行了分析,所得结论可供类似机组在电除尘器改造和设计时参考。  相似文献   
37.
● pz-UiO-66 was synthesized facilely by a solvothermal method. ● Efficient capture of copper from highly acidic solution was achieved by pz-UiO-66. ● pz-UiO-66 exhibited excellent selectivity and capacity for copper capture. ● Pyrazine-N in pz-UiO-66 was shown to be the dominant adsorption site. The selective capture of copper from strongly acidic solutions is of vital importance from the perspective of sustainable development and environmental protection. Metal organic frameworks (MOFs) have attracted the interest of many scholars for adsorption due to their fascinating physicochemical characteristics, including adjustable structure, strong stability and porosity. Herein, pz-UiO-66 containing a pyrazine structure is successfully synthesized for the efficient separation of copper from strongly acidic conditions. Selective copper removal at low pH values is accomplished by using this material that is not available in previously reported metal–organic frameworks. Furthermore, the material exhibits excellent adsorption capacity, with a theoretical maximum copper uptake of 247 mg/g. As proven by XPS and FT-IR analysis, the coordination of pyrazine nitrogen atoms with copper ions is the dominant adsorption mechanism of copper by pz-UiO-66. This work provides an opportunity for efficient and selective copper removal under strongly acidic conditions, and promises extensive application prospects for the removal of copper in the treatment for acid metallurgical wastewater.  相似文献   
38.
为解决低C/N污水和高浓度白酒废水(HCBW)处理所面临的问题,采用移动床生物膜反应器(MBBR),构建了白酒窖底废水与模拟低C/N生活污水协同处理系统,以改性海绵填料和流化床填料分别探究HCBW作为反硝化外加碳源对低C/N生活污水处理的影响。结果表明:海绵填料协同处理系统(A1)对COD、${\rm{NH}}_4^+ $-N、TN和色度的平均去除率分别为91.29%、99.08%、89.81%和80.66%,流化床填料系统(A2)的平均去除率分别为90.51%、98.58%、75.73%和76.07%,改性海绵填料的去除效果优于流化床填料;混合废水经过MBBR系统处理后,${\rm{NH}}_4^+ $和TN得到了有效去除,出水中的醇类、硫酸盐和磷酸盐物质的相对比例有一定程度增加;协同处理系统A1和A2的硝化优势菌属均为Nakamurella、Nitrospira,反硝化优势菌属均为Amaricoccus、Dokdonella和Thermomonas,可能参与有机物去除的优势功能菌属均为Micropruina。通过功能预测得出:协同处理系统A1、A2中的主要代谢通路均为氨基酸代谢、碳水化合物代谢和能量代谢,主要的环境信息处理通路均为复制与修复和转译,主要的遗传信息处理通路均为膜运输。以上研究结果可为HCBW的资源化利用、低C/N生活污水处理提供参考。  相似文献   
39.
对武钢烧结厂401转运站除尘管道经常堵塞的原因进行了理论分析和计算,计算结果与工艺要求的有关参数进行对照,找出了现有除尘管道堵塞的原因,并提出了相关的改进措施.  相似文献   
40.
石油天然气钻探过程中硫化氢的监测   总被引:9,自引:0,他引:9  
石油天然气钻探过程中硫化氢的准确监测是确保钻井安全的条件。在介绍硫化氢气体的性质、危害的基础上具体阐述了现场常用硫化氢监测方法。对现行井场硫化氢监测问题进行了探讨,提出了硫化氢监测应从监测地面气体向监测地层流延伸,硫化氢报警内容应多样化的建议。  相似文献   
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