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811.
目的:评估职业病防护设施防护效果,促进现场职业病防护,保护职工身体健康。方法:运用职业卫生检测法、现场调查法等方法对某建设项目进行职业病危害控制效果卫生学评价。结果:有毒物质检测均符合相关标准要求,天然气压缩机处噪声达94.3dB(A),超过职业接触限值。结论:改进噪声防护设施,达到相关标准要求。 相似文献
812.
Tianwei Qian Shushen Li Qingwei Ding Guibin Wu Dongye Zhao 《Journal of environmental radioactivity》2009
90Sr is a fission byproduct of uranium and plutonium, and it presents a major health problem in the environment. A field test on the transport of various radionuclides including 90Sr in an unsaturated Chinese loess was conducted under artificial rain conditions from July 1997 to August 2000. The vertical concentration distribution of 90Sr displayed an unusual profile of double concentration peaks, which were separated by a thin (0.7 cm) source layer. In order to interpret the double-peak concentration profile, the transport of 3H and 90Sr in the unsaturated Chinese loess under artificial sprinkling conditions was simulated using WATERM, a numerical code for simulating flow field, and NESOR, also a numerical code but for simulating nuclide migration. The models were able to adequately simulate the double-peak concentration profile. The observation suggested that the fine arenaceous quartz layer, though 0.7 cm thick, formed a capillary barrier together with the local loess, which prevented water from penetrating. A significant discrepancy was observed between the model-fitted distribution coefficient (Kd) of 90Sr and that determined from independent laboratory experiments, which can be attributed to a number of factors such as the capillary barrier effect, solution-to-solid ratio and soil water content. Therefore, when the model is used for predictive purposes where Kd is used as an input parameter, Kd must be determined under well controlled conditions by taking into account these factors as well as the heterogeneity in the field. 相似文献
813.
Haiyan Chen Yiqun Zhang Bo Gao Yang Xu Qi Zhao Juan Hou Jin Yan Guijie Li Hui Wang Lan Ding Jie Ding Chun Zhao 《Environmental science and pollution research international》2013,20(12):8567-8578
Group-selective magnetic molecularly imprinted polymers (MMIPs) that can extract four widely used sulfonamide antibiotics and their acetylated metabolites from environmental water were synthesized in this study. The MMIPs with saturation magnetization value of 16.7 emu g-1 could be separated from the environmental water samples easily by the application of an adscititious magnetic field, reducing the time consumption of pretreatment. The extraction conditions were evaluated, and optimal extraction conditions were as follows: extraction time, 25 min; amount of polymers, 90 mg; washing solvent, 30 % methanol aqueous solution; and elution solvent, methanol–acetic acid (95:5, v/v). The target analytes were detected by liquid chromatography–tandem mass spectrometry, and the detection limits of the method are in the range of 0.38–1.32 ng L-1. The relative standard deviations of intra- and inter-day are in the range of 1.3–6.8 % and 1.7–9.1 %, respectively. The proposed method is suitable for the analysis of environmental water samples. 相似文献
814.
Response to environmental flows in the Lower Tarim River, Xinjiang, China: an ecological interpretation of water-table dynamics 总被引:4,自引:0,他引:4
Increased water-dependent development and utilization have led to significant environmental and hydrological degradation of the Tarim River in western China and its dependent ecosystems. Between the 1950s and 1970s, 350 km of the lower reaches were drained and between 1960 and 1980 the water-table fell from between −2 and −3 m to between −8 and −10 m. Subsequently, riparian ecosystems were seriously degraded. In 2000, the Chinese government launched a program to restore the lower reaches of the river. Four environmental flows of 1034×106 m3 were released from 2000 to 2002. This paper interprets and discusses the ecological significance of changes following the releases and identifies the relationship between water-table dynamics and vegetation responses. Short-term objectives for river restoration are proposed with possible monitoring parameters suggested. 相似文献
815.
本研究选择腐植酸(HA)、黄腐酸(FA)和鸡粪提取的可溶性有机质(DOM)三种天然有机质,加入供试土壤,以溴离子作为示踪剂,通过四组模拟土柱实验,获得不同有机质组成的土壤中As (V)的穿透曲线,并用CXTFIT 2.1软件拟合,计算阻滞系数Rd值,同时测定流出液中As (V)的形态变化。结果表明:HA抑制了As (V)的迁移,而加入FA和DOM后As (V)在土壤中的移动性显著增强。四种处理(CK、土壤+HA、土壤+FA、土壤+DOM)中As (V)的阻滞系数Rd值分别为17.82、19.53、10.13和12.2,土柱中残留的As分别占As总量的27.4%、31.7%、19.2%和18.2%。腐植酸以芳香族含量为主,分子量较大,吸附固定As的能力较强;黄腐酸和提取的可溶性有机质主要结构为烷基碳和氧烷基碳,H/C和O/C值较高,与As存在竞争吸附,促进As的迁移。 相似文献
816.
水电工程抗震设防概率水准和地震作用概率模型 总被引:7,自引:0,他引:7
本文基于我国已有的二十余个重大水利水电工程场地地震危险性分析的结果,运用概率分析方法探讨了水电工程抗震设防的概率水准和地震作用的概率模型,以便为正在修订中的《水工建筑物抗震设计规范》提供依据。 相似文献
817.
侯茂生 《防灾减灾工程学报》1997,(2)
总结了在南黄海6.1级地震应急中的成功经验:本省及有关城市充分发挥防震减灾工作的政府职能,各级领导决策及时,指挥果断、地震专业科技人员尽心尽职,迅速判断震情,安抚民心以及新闻部门反应快,报道勤,收效好。并由此提出南黄海6.1级地震应急的3点体会和进一步做好大中城市地震应急工作的3点建议 相似文献
818.
819.
生物化学协同除磷研究 总被引:7,自引:0,他引:7
采用聚合硅酸铝和聚合硅酸铁两种混凝剂,比较了将混凝剂直接投加到反应器中和对生物反应器出水再进行混凝沉淀2种工艺的除磷效果,并对2种混凝剂的除磷效果进行了比较。结果表明:对于聚合硅酸铝,没有生物协同作用;对于聚合硅酸铁,投加量在40mg/L以下时具有生物协同作用,30mg/L时协同作用最明显;而且聚合硅酸铁的除磷效果好于聚合硅酸铝。 相似文献
820.
Longyi Shao Lingli Chang Robert B. Finkelman Wenhua Wang Junxia Liu Jie Li Jiaoping Xing Cong Hou 《环境科学学报(英文版)》2020,32(11):96-101
Emission from burning coals is one of the major sources of the airborne particles in China. We carried out a study on the rare earth elements (REEs) in the inhalable particulate matter (PM10) emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system. Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes. The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquette-burning PM10. In addition, the contents of the light rare earth elements (LREEs) are higher than those of the heavy rare earth elements (HREEs) in the PM10 emitted from burning the coals and briquettes, demonstrating that the REEs in both the coal-burning and briquette-burning PM10 are dominated by LREEs. The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals. A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes, being lower than 2, are lower than those in the particles from gasoline-powered vehicle emission. 相似文献