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121.
选择单因子指数法、综合指数评价法及模糊综合评价法对漕桥河2008年—2011年的水质进行评价,并结合评价结果对3种评价方法进行分析比较。结果表明,采用模糊综合评价方法可以正确、全面地反映漕桥河的水质状况。 相似文献
122.
We conducted a laboratory evaluation to assess the risk to early life stage (i.e., eyed egg to swim up) fall Chinook salmon
(Oncorhynchus tshawytscha) for exposure to hexavalent chromium from a contaminated groundwater source. Local populations of fall Chinook salmon were
exposed to Hanford Site source groundwater that was diluted with Columbia River water. Specific endpoints included survival,
development rate, and growth. Tissue burdens of fish were also measured to estimate uptake and elimination rates of chromium.
Survival, development, and growth of early life stage fall Chinook salmon were not adversely affected by extended exposures
(i.e., 98 day) to hexavalent chromium ranging from 0.79 to 260 μg/l. Survival for all treatment levels and controls exceeded
98% at termination of the test. In addition, there were no differences among the mean lengths and weights of fish among all
treatment groups. Whole-body concentrations of chromium in early life stage fall Chinook salmon had a typical dose-response
pattern; i.e., those subjected to highest exposure concentrations and longest exposure intervals had higher tissue concentrations.
Given the spatial extent of chromium concentrations at the Hanford Site, and the dynamics of the groundwater–river water interface,
the current cleanup criterion of 10 μg/l chromium appear adequate to protect early life stage fall Chinook salmon. These findings,
together with previous research indicate low risk to these populations. 相似文献
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124.
A mine’s ventilation system is an important component of an underground mining system. It provides a sufficient quantity of air to maintain suitable working environment. Therefore, the status of mine ventilation should be tracked and monitored as a timely matter. Based on former findings and in-depth analysis of mine ventilation systems, a proper early warning model is proposed in this paper for such considerations to improve the mine ventilation safety. The model itself is comprised of two sub-models, and two data mining techniques are used to assist in building each sub-model. One is the optimal indexes selection model which applies the Rough Set theory (RS) to assist the selection of best ventilation indexes. The other is the risk evaluation model based on the Support Vector Machine (SVM) to classify the risk ranks for the mine ventilation system. Testing cases have been used to demonstrate the applicability of this integrated model. 相似文献
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126.
由于化学分析设备与技术的不断提高,大量的有机化学物质不断地从环境介质和食品中被检出。尽管这些物质的浓度很低,但是毒理学的研究表明,一些环境内分泌干扰物质(Environmental Endocrine Disruptors,EDCs)在很低浓度就能导致生物健康负效应。如何在种类众多的环境化学物质,以及在成分复杂的环境提取物中识别具有低剂量效应的有害物质并加以管理十分重要。本文以EDCs为对象,结合近几年来的文献,综述了其可能造成的危害,重点分析了EDCs的作用机制、筛选评估方法及生物检测技术,旨在为今后环境有害物质的筛选与风险识别研究提供借鉴。 相似文献
127.
在分析了浑河流域水环境监测、监控与管理等方面信息化现状的基础上,提出了构建浑河流域水环境风险评估及预警平台的总体软件架构,并介绍了架构中各部分的构成和具体功能,最后讨论了平台构建的关键技术。 相似文献
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129.
Collecting data in artisanal and small-scale mining communities: Measuring progress towards more sustainable livelihoods 总被引:3,自引:0,他引:3
Marieke Heemskerk 《Natural resources forum》2005,29(1):82-87
This short note discusses methodological obstacles to the collection of microeconomic data in artisanal and small-scale mining communities. International donor organizations are supporting policy efforts that enhance the contribution to poverty alleviation of this mining subsector. The design and evaluation of such policy interventions require data on income, expenditure, investment, and savings in mining households and communities. These data are difficult to come by. Incomes are variable; migrants may work far from home; miners often work informally and sometimes illegally; mining populations and communities are heterogeneous and transient; and miners have many reasons to distort information. Legalization and organization of miners in cooperatives would facilitate documentation and research. These processes, however, are beyond the control of the typical policy consultant or donor organization. On their part, these parties can adopt an alternative model of research. This model involves the community in project development, data collection, and monitoring. It emphasizes continuity, cultural diversity, trust building and learning. The data thus collected should provide a firm basis for programmes that promote more sustainable livelihoods in artisanal and small-scale mining communities. 相似文献
130.
随着我国人口的增长及人民物质生活水平的不断提高,灌区工程作为粮食安全的重要保障,未来其建设步伐将不断向前迈进,而作为预防、治理生态破坏的基础,灌区工程开展生态环境影响评价的现实意义及作用将日益显著。本文介绍了大中型灌区工程主要生态环境影响,及灌区工程生态环境影响评价特点和重点,并对灌区工程生态环境影响评价进一步完善与发展进行了展望。 相似文献