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991.
采用低与高两个浓度组,进行慢与急性致毒效应实验结果表明,在低浓度组(0.5-30mg/L)锯缘青蟹没有发生急性毒性死亡的现象,但其摄食量呈现减少;在高浓度组(63~500mg/L)锯缘青蟹出现急性中毒死亡,且死亡率随毒物浓度的增加而上升,测得苯胺对锯缘青蟹的24hLC50为151±69mg/L;48h LC50为91.2±5.2mg/L.在致毒浓度范围内,锯缘青蟹对苯胺积累的富集因子接近1.6,这表明生物体与海水浓度之间存在某种配比平衡的关系。 相似文献
992.
993.
Comparative Analysis of New Zealand and US Approaches for Agricultural Nonpoint Source Pollution Management 总被引:1,自引:0,他引:1
Brian S. Caruso 《Environmental management》2000,25(1):9-22
The role of the central government in New Zealand is generally limited to research and policy development, and regional councils
are responsible for most monitoring and management of the problem. The role of the federal government in the United States
includes research and monitoring, policy development, and regulation. States also have a significant management role. Both
countries rely on voluntary approaches for NPS pollution management. Very few national water quality standards exist in New
Zealand, whereas standards are widely used in the United States. Loading estimates and modeling are often used in the United
States, but not in New Zealand. A wide range of best management practices (BMPs) are used in the United States, including
buffer strips and constructed/engineered wetlands. Buffer strips and riparian management have been emphasized and used widely
in New Zealand.
Many approaches are common to both countries, but management of the problem has only been partly successful. The primary barriers
are the inadequacy of the voluntary approach and the lack of scientific tools that are useful to decision-makers. More work
needs to be performed on the evaluation of approaches developed in both countries that could be applied in the other countries.
In addition, more cooperation and information/technology transfer between the two countries should be encouraged in the future. 相似文献
994.
995.
中国加入WTO将使国内环保企业竞争更为激烈 ,使国内环保机械企业生存变得更为艰难。同时 ,由于经验丰富的国外企业已将凭借实力占据国际市场 ,使得我国环保机械企业在国际市场竞争中处于不利地位。从另一方面讲 ,中国加入WTO可以促进我国政府采取有力措施 ,加强对环保市场的监管 ,克服无序竞争 ,为国内企业营造良好的竞争环境 ;加入WTO可以加快国内环保机械企业技术创新 ,开发具有国际水准的拳头产品 ,增强市场竞争力 ,同时 ,可以推动国内产业结构调整及资本运营 ,使环保机械企业快速发展壮大 ;另外 ,WTO的加入可以迫使国内环保机械企业学习国外先进经验 ,掌握全球经济知识 ,夯实参与国际市场竞争的基础。 相似文献
996.
Urban Environmental Management in Botswana: Toward a Theoretical Explanation ofPublic Policy Failure
ELISHA N. TOTENG 《Environmental management》2001,28(1):19-30
For the last three and half decades, Botswana has been widely acclaimed to be one of sub-Saharan Africa's longest and most
stable liberal democracies, coupled with and sustained by a growing economy. One of the major contradictions, however, within
this development scenario, has been the neglect of environmental problems in the country in general, and urban environmental
issues in particular.
Part of the problem fueling the misconception of environmental issues in Botswana is the state's domination of the country's
environmental agenda. This is linked to the power disjunction in decision-making and policy processes between state and nonstate
actors over the most appropriate course of action to tackle the problems. Without adopting appropriate analytical frameworks,
it is possible that the problem of urban environmental mismanagement in Botswana will persist. This article examines some
of the major urban environmental issues in Botswana from neighborhood, citywide, and urban–rural interface perspectives. Further,
the elite theory of public policy is used to explain constraints on policy change in the urban environmental management arena
in Botswana. 相似文献
997.
A conceptual model is developed herein for the purpose of stimulating discussions within groups planning and carrying out
integrated natural resource projects. We first describe four basic components of integrated planning and modeling efforts:
people, databases, technology, and organizational commitment. Second, we provide one view of the relationship between the
size of the project's decision-making body and the timing of decisions during a project's life cycle. Finally, these two discussions
are combined into a conceptual model describing the dynamic nature of decision-making within integrated projects. The abstractions
and generalizations described here are not unique to private industry or governmental organizations and should provide the
basis for a discussion of decision-making issues among interdisciplinary professionals embarking on large-scale or complex
modeling efforts. 相似文献
998.
Summary. To exploit biologically active compounds from white clover (Trifolium repens L.) for suppressing weeds and soil-borne diseases, either as isolated products (biopesticides) or through cultivars with
enhanced production of these compounds, the biologically active compounds must be identified, plant content measured, and
their fate in soil known. The present review summarizes the published knowledge needed for such exploitation; providing essential
information on structure and concentration of flavonols, flavones, condensed tannins, isoflavones, isoflavanones, pterocarpans,
coumestans, cyanogenic glucosides, and saponins in healthy and stressed white clover plants. Various stresses and particular
cultivars affect the concentrations of several of the compounds. Information on biological effects and the degradation/transformation
of these compounds in plants or by microorganisms is available. There is no information on the degradation pathway in soil,
the mechanisms of exudation and leaching of compounds from plants, and soil sorption properties of the compounds. The clover
soil fatigue problem is increasing in grasslands and causes problems especially in organic farming. Research efforts focused
on biological elements of clover soil fatigue have not explained it, and the influence of secondary metabolites has not been
investigated. There are few investigations into the interaction between beneficial fungi/fungal-diseases and the occurrence
of biologically active secondary metabolites in white clover plants. Such studies are critical to better understand beneficial
fungi and pathogens. 相似文献
999.
UASB-CASS-接触氧化工艺处理玉米酒精废水 总被引:6,自引:1,他引:5
介绍了采用UASB-CASS-接触氧化工艺处理玉米酒精废水的工程应用。实际运行表明玉米酒精生产工艺在采取清洁生产措施条件下,酒精生产装置混合生产废水CODCr、BOD5、SS分别控制在8000mg/L、3200mg/L和1500mg/L以内,经过UASB+CASS+接触氧化工艺处理后,外排废水可以达到《污水综合排放标准》(GB8978-1996)一级标准。同时,对废水处理过程中污泥和沼气利用途径进行了探索,为解决废水二次污染问题提供了可借鉴的实践经验。 相似文献
1000.
同分异构体喹啉和异喹啉的缺氧降解性能比较 总被引:3,自引:0,他引:3
研究了同分异构体的含氮杂环化合物喹啉和异喹啉在缺氧条件下的降解情况,发现两者表现出不同的缺氧降解特性。喹啉可以在缺氧条件下得到有效降解,其缺氧降解的最佳碳氮比为8。在最佳碳氮比条件下,喹啉的缺氧降解过程符合一级动力学规律,在其降解过程中首先以硝酸盐为电子受体,当硝酸盐氮浓度为零时,亚硝酸盐氮浓度达到最高,此后喹啉的降解主要以亚硝酸盐为电子受体,并和亚硝酸盐氮同时达到最低浓度。异喹啉对硝酸盐的利用甚微,其降解主要表现为厌氧降解特征,降解过程符合零级动力学规律。 相似文献