首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   91篇
  免费   3篇
  国内免费   3篇
安全科学   10篇
废物处理   3篇
环保管理   23篇
综合类   24篇
基础理论   12篇
污染及防治   16篇
评价与监测   5篇
社会与环境   4篇
  2022年   2篇
  2020年   3篇
  2017年   6篇
  2016年   7篇
  2015年   6篇
  2014年   11篇
  2013年   10篇
  2012年   1篇
  2011年   8篇
  2010年   4篇
  2009年   9篇
  2008年   5篇
  2007年   7篇
  2006年   7篇
  2005年   3篇
  2004年   3篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1998年   1篇
  1997年   1篇
排序方式: 共有97条查询结果,搜索用时 437 毫秒
81.
In this work, the evolution of the chemical-environmental risk oriented to the spatial planning in the autonomous community of Andalusia was carried out over the 2002–2012 decade. Indicators for determining the variables representing the risk, such as hazard, vulnerability and proximity, were then defined based on a consequence-based approach analysis risk methodology. A suitable mathematical combination based on spatial analysis methods supported by ArcGIS platform was also applied, which resulted in a quantitative and qualitative risk value and provided the territorial compatibility in the study area for each year. Finally, once the indicators that determine the risk level for 2002 and 2012 were obtained, they were combined in order to find out the risk tendency of the region for the whole decade.  相似文献   
82.
The impact of contemporary agriculture on Danish lakes is acknowledged to be extreme. In particular, high loading of nutrients from agricultural soils contributes to the eutrophic conditions found in many of Denmark’s lakes. Palaeolimnological studies have shown that human disturbance of the Danish landscape since the introduction of agriculture around 6,000 years ago has had a major impact on lake ecosystems. The European Union’s Water Framework Directive requires an evaluation of reference conditions for lakes, the conditions expected with only minimal human impact. Monitoring data and palaeolimnological studies of Danish lakes demonstrate that many of the most detrimental effects of eutrophication have been experienced in recent decades. A new study has suggested that the reference status for Danish lakes may be set to the status in ad 1850–1900, probably providing attainable, realistic restoration targets for many sites. The aims of this study were to explore the impacts of past and contemporary land-use on Danish lakes, and to consider how appropriate the use of 1850 as a date to define reference status is for these sites. Catchment land-cover data for ad 1800, taken from historical maps, and sedimentary diatom assemblages of the same age, from dated sediment cores, were used to assess the impact of pre-industrial land-use on 20 Danish lakes. Analysis of contemporary land-cover data and surface-sediment diatom assemblages for the 20 sites was also made. In-lake total phosphorus (TP) concentrations were estimated using the sedimentary diatom assemblages and an existing calibration dataset for Danish lakes. The percentage of the lake catchment that was agricultural land in ad 1800 explained 8.8% of the total variation in the diatom data. The land-cover variables ‘built-up areas’ and ‘plantations’, together explained 16.9% of the variation in the diatom data for the modern samples. Diatom-inferred TP concentrations were high for both ad 1800 (mean 112 μg TP L−1) and the present (mean 122 μg TP L−1), the latter estimates reflecting efforts in recent decades to reduce nutrient loading to Danish lakes following very high levels of nutrient enrichment post-1950. The data presented highlight the impact that human activities 200 years ago, particularly agriculture, had on Danish lake systems. The long cultural history and major anthropogenic disturbance of the Danish landscape mean that true reference conditions for lakes (or ‘baseline’ conditions, those found prior to human impacts) can be found only by considering century to millennial timescales.  相似文献   
83.
Large amounts of waterborne nutrients are major problems for society since they can cause harmful algal blooms in surface water bodies. Consequently, there are a variety of national and international guidelines, e.g. Swedish National Environmental Quality Objectives and the EU Water Framework Directive, which include targets to be achieved within a certain time frame. This paper uses the example of a large Swedish lake to show that national and international targets must be adapted to the local situations. Despite decreasing nutrient concentrations, cyanobacterial blooms in the lake have increased over recent years. We found that these blooms coincide with depleted nitrate–nitrogen concentrations and increased water temperatures. We propose a simple model with water temperature, nitrate–nitrogen and total phosphorus concentrations as input variables as a basis for formulation of regional eutrophication targets. Political decisions should be preceded by open discussion between policymakers and scientists to differentiate between real knowledge, assumptions or feelings. For optimal results, recommendations for reducing nutrient load should consider all sources, including urban stormwater and wastewater from rural houses, and should be founded on a balanced reduction in emissions of algae-available nutrients. In addition, climate change calls for more effective environmental policy to protect surface water resources.  相似文献   
84.
This paper discusses the development and use of the first version of the WFD Explorer (WFDE), a decision support system (DSS) for the implementation of the Water Framework Directive in the Netherlands. The paper's aim is to increase our understanding of the development process of DSSs and the impact the development process has on the perceived validity and usefulness of the DSS. In other words, whether the DSS is seen as representing reality correctly and as fit for purpose and user-friendly. Contrary to the expectations, the WFDE was not used much. Tensions in the development process over the intended users, the level of analysis, the level of ambition and the type of expertise to be included have contributed to doubts over its usefulness and validity. These tensions reflect general tensions in river basin management: different actors will prefer different approaches, and none of these is objectively the best. Whereas guidelines for the development of DSSs can increase awareness of these tensions, resolving these tensions is beyond the power of the developers to control. Guidelines have their use, but also their limitations, simply because they are general and circumstances differ from case to case.  相似文献   
85.
Reference conditions are a key concept in the European Water Framework Directive (WFD). The WFD stipulates that the ecological status of a given water body shall be assessed by quantifying the deviation from a set of reference conditions that represent the stable state of an ecosystem in the absence of significant human disturbance. This concept is subject to criticism from several authors, particularly because underlying ecological concepts are weak and the distinction between natural variability and the effects of anthropogenic activities on ecosystem function will become increasingly artificial. In this paper, a sociologist and an aquatic ecologist examine the origin, successes and limits of the reference conditions concept and raise important questions about applying this concept in practice. We argue that this concept fitted specific needs from different institutions and stakeholders which promoted the WFD. Monitoring practices using this concept require some adaptations. Setting goals for restoration based on reference conditions is more problematic. A more adaptive management approach would be wiser.  相似文献   
86.
Traditional flood protection methods have focused efforts on different measures to keep water out of floodplains. However, the European Flood Directive challenges this paradigm (Hartmann and Driessen, 2013). Accordingly, flood risk management plans should incorporate measures brought about by collaboration with local governments to develop and implement these measures (Johann and Leismann, 2014). One of the challenges of these plans is getting and keeping stakeholders involved in the processes related to flood risk management. This research shows that that this challenge revolves around how flood risks are socially constructed.Therefore it is essential to understand and explain the risk perception of stakeholders. System Theory by Luhmann provides the analytical distinction between ‘internal risk’ and ‘external danger’ as key concepts to understand whether or not stakeholders will take action (Luhmann, 1993). While perceptions of ‘external danger’ will not lead to action, perceptions of ‘internal risk’ urge stakeholders to take action.The cases of the rivers Lippe and Emscher in the dense populated region between Duisburg and Dortmund in Germany illustrate how these theoretical concepts materialise in practice. This contribution shows how flood risks are socially constructed and how this construction is influenced by the European flood risk management plan. While clearing up some of the difficulties from the Flood Directive, the research shows a gap between the Flood Directive and the current theory and planning practice, which needs to be addressed in further research.  相似文献   
87.
88.
晋江流域工业环境风险评价研究   总被引:3,自引:0,他引:3       下载免费PDF全文
为了预防由于工业企业危险物质泄漏引发的环境突发事故,保护流域水环境安全.本研究选用基于Seveso III指令模型的方法进行流域环境风险评价研究,并对模型进行适应性改进,选择工业企业分布较为密集的泉州晋江流域进行了示范研究.利用高程、企业分布、危险物质储存量等数据,得到企业内在风险;叠加区域易受损性后得到子区域的环境风险.结果表明,南安市是晋江流域环境风险最高的子区域,风险值高达108,安溪县和泉州市区风险水平居中,晋江市为低度危险子区域.在此基础上,根据评价结果提出了具有针对性的流域环境风险控制建议.  相似文献   
89.
富营养化问题正在污染地球上宝贵的饮用水资源。因此,防治和解决富营养化问题是全球的一项紧急任务。早在上个世纪,很多欧洲国家在富营养化的控制方面已经做了很多研究,尤其是对欧盟的立法与国家政策方面的研究。目前,很多欧洲国家都建立了相对完善的综合政策。中国太湖也面临着严重的水体富营养化问题。文章选取荷兰和英国作为案例分析,通过与太湖水体富营养化防治中存在的问题的对比和分析,提出一些可行性建议,对太湖水域的该问题的缓解起到一定的借鉴作用。  相似文献   
90.
富营养化问题正在污染地球上宝贵的饮用水资源.因此,防治和解决富营养化问题是全球的一项紧急任务.早在上个世纪,很多欧洲国家在富营养化的控制方面已经做了很多研究,尤其是对欧盟的立法与国家政策方面的研究.目前,很多欧洲国家都建立了相对完善的综合政策.中国太湖也面临着严重的水体富营养化问题.文章选取荷兰和英国作为案例分析,通过与太湖水体富营养化防治中存在的问题的对比和分析,提出一些可行性建议,对太湖水域的该问题的缓解起到一定的借鉴作用.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号