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为了解云南省文山州南北河表层沉积物中重金属的污染状况,2021年1月采集干流7个样点的沉积物样品,对沉积物中的Pb、Cd、As、Zn、Cu、Ni、Cr进行实验室检测。通过地累积指数法、潜在生态风险指数法对检测指标进行分析。结果表明:以地累积指数法评价,南北河沉积物重金属主要污染因子为As、Cd、Zn、Pb、Cu,Ni和Cr为无污染;以潜在生态危害指数法评价,南北河干流沉积物7种沉积物呈现不同生态风险,其中Cd为低生态风险—极强生态风险,As为低生态风险—中强生态风险,Pb、Zn、 Cu、 Ni、 Cr为低生态风险。As和Cd为南北河干流主要污染和生态风险来源。 相似文献
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对合肥市南淝河表层沉积物中重金属污染状况进行采样调查,选取了8个采样点,测定了沉积物中Cr、Cd、Pb、Ni、Zn、Cu 6种重金属的含量,并采用地质累积指数法和Hakanson潜在生态风险指数法对其污染程度进行分析评价。地质累积指数评价结果表明:南淝河6种重金属的生态风险等级由强至弱依次为Cd、Zn、Cu、Ni、Pb、Cr;生态风险指数评价结果显示:在南淝河沉积物重金属中,Cd存在一定的潜在生态风险,Cr、Pb、Ni、Zn、Cu均处于轻微等级,重金属生态风险等级由强至弱依次为Cd、Cu、Ni、Pb、Zn、Cr,多数采样点的沉积物重金属综合潜在生态风险等级处于轻微级,个别采样点达到了中等甚至强生态风险等级。 相似文献
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近几年,海洋沉积物中重金属含量明显升高,极大程度上危害了海洋底栖生物的生命健康。因此,为评价海洋沉积物污染特征与生态风险指数,本文以广西防城港为例,对防城港近海区设置取样监测点(A1~A10),按照春、夏、秋、冬四季测定海水表层沉积物中重金属元素(Cu铜、Pb铅、Cd镉、Zn锌)的含量,并采用单因子指数法、综合污染指数法与潜在生态风险指数法分析沉积物的污染特征与生态风险。结果表明,第一,该海洋沉积物中Cu、Pb、Cd、Zn的年均含量分别为15.47、18.42、0.275、64.07mg/kg,沉积物综合污染指数大于10,说明海洋沉积物呈现较高污染状态。第二,该海洋沉积物中重金属对南海海域潜在生态风险属于中等水平,重金属危害大小顺序排列为Cd> Cu> Pb> Zn。 相似文献
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伊通河有长春市"母亲河"的称号,河流表层沉积物中重金属污染对河流生态健康有重要影响。现对伊通河城区段3个典型断面进行划分,分析河流表层沉积物中5种重金属元素含量,采用单一重金属潜在生态风险对表层沉积物重金属污染程度进行评价及分析。结果表明,河流表层沉积物中重金属除Cr外,Cu、Zn、Cd和Pb平均含量均超过省内土壤背景值;根据单一重金属潜在风险指数表明,重金属Cu、Zn、Cr和Pb生态风险因子评价为轻微,属于低污染状态,中游段重金属Cd相较上游段及下游段风险因子高。 相似文献
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石煤尾矿区土壤重金属污染风险评价 总被引:1,自引:0,他引:1
以某石煤尾矿库及周边农田表层土壤为研究对象,采用TCLP法对土壤中Pb,Cd,Cu,Zn的生物可利用态风险进行评价,并运用Hakanson潜在生态风险指数法综合评价其潜在生态危害程度。结果表明:研究区土壤中Pb,Cd,Cu,Zn的平均质量分数均高于陕西省土壤元素背景值标准;TCLP法提取的重金属质量分数与国际标准值相比较,除Cu和Zn之外,Cd和Pb元素均超标;相关性分析表明,研究区土壤中除Pb和Cu之间呈显著正相关关系,其余元素两两之间呈极显著正相关关系;潜在生态风险评价结果表明,研究区土壤中Pb,Cd,Cu,Zn潜在生态风险综合指数均值为491.71,属强生态危害程度,Cd元素是构成潜在生态风险的主要因子。石煤尾矿库已对周围土壤造成重金属污染危害。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%. 相似文献
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塔设备改造选型的分析 总被引:2,自引:0,他引:2
就当前扩产增容中塔设备设计和改造时板式塔和填料塔的选型问题加以分析。在评述目前国内常用的几种塔板和新型填料之后,着重介绍一种新型塔板(导向梯形浮阀塔板)和一种新型填料(波环填料——乾隆帕克)。 相似文献