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   15篇
  免费   1篇
废物处理   2篇
环保管理   2篇
综合类   2篇
基础理论   3篇
污染及防治   7篇
  2021年   1篇
  2020年   1篇
  2017年   2篇
  2016年   1篇
  2010年   3篇
  2009年   2篇
  2008年   2篇
  2005年   3篇
  1993年   1篇
排序方式: 共有16条查询结果,搜索用时 15 毫秒
11.
12.
Haematuria-inducing areas in the northern and central parts of the Eastern Carpathian Mountains are characterised by the mesozoic-crystalline, neogene eruptive and transcarpathian flysch zones. The rocks have high concentrations of some metals and radioactive elements, some of them bearing polymetallic sulphides. The soils are strongly or moderately acid and oligomesobasic. They have a deficiency of soluble phosphorus and molybdenum, but up to 4.9 times the background content of metallic elements in non-affected zones. The waters have a pH around 7, a low content of salts (0.09–0.62 g L–1), but metal levels in excess of 10 times that of the background level. Pasture vegetation has a low nutritional value, and includes up to 12% of poisonous plant species. It is characterised by low total concentrations of P, Mo, N and K, and high total concentrations of metallic trace elements, including high values of Zn and excessive values of Fe, Mn, Pb, Cr, Ni, Cd and Al. Besides clinical symptoms specific to haematuria, sick animals have abnormal blood and urinary compositions and specific morphopathological features. High concentrations of metallic elements were detected in renal calculi. The correlation of the geochemical and biogeochemical features of the haematuria-inducing areas, together with the results of the epizootological, clinical, paraclinical and morphopathological research emphasises that chronic cattle haematuria is a disease with numerous causes, but is primarily a biogeochemical problem in the area studied, making it an ecosystem disease.To whom correspondence should be addressed.  相似文献   
13.

Background, aim, and scope  

The need for global and integrated approaches to water resources management, both from the quantitative and the qualitative point of view, has long been recognized. Water quality management is a major issue for sustainable development and a mandatory task with respect to the implementation of the European Water Framework Directive as well as the Swiss legislation. However, data modelling to develop relational databases and subsequent geographic information system (GIS)-based water management instruments are a rather recent and not that widespread trend. The publication of overall guidelines for data modelling along with the EU Water Framework Directive is an important milestone in this area. Improving overall water quality requires better and more easily accessible data, but also the possibility to link data to simulation models. Models are to be used to derive indicators that will in turn support decision-making processes. For this whole chain to become effective at a river basin scale, all its components have to become part of the current daily practice of the local water administration. Any system, tool, or instrument that is not designed to meet, first of all, the fundamental needs of its primary end-users has almost no chance to be successful in the longer term.  相似文献   
14.
In the Retezat Mountains concentrations of O3, NO2 and SO2 in summer season 2000-2002 were low and below toxicity levels for forest trees. While NH3 concentrations were low in 2000, the 2001 and 2002 concentrations were elevated indicating possibility for increased N deposition to forest stands. More than 90% of the rain events were acidic with pH values <5.5, contributing to increased acidity of soils. Crown condition of Norway spruce (Picea abies) and European beech (Fagus sylvatica) was good, however, defoliation described as >25% of foliage injured increased from 9.1% in 2000 to 16.1% in 2002. Drought that occurred in the southern Carpathians between fall 2000 and summer 2002 and frequent acidic rainfalls could cause the observed decline of forest condition. Both Norway spruce and European beech with higher defoliation had lower annual radial increments compared to the trees with low defoliation. Ambient O3 levels found in the Retezat did not affect crown condition of Norway spruce or European beech.  相似文献   
15.
This paper deals with process identification and model development for the case of a porous reference material leaching under certain hydrodynamic conditions. Four different dynamic leaching tests have been applied in order to take into account different types of solid/liquid contact conditions corresponding to various real leaching scenarios: monolithic and granular material with sequential eluate renewal, and granular material and continuously renewed eluate with different hydrodynamic conditions (dispersion, residence time). A coupled chemical-mass transfer model has been developed to describe the leaching behaviour under all experimental conditions. Diffusion has been considered as the mass transport mechanism inside the saturated porous material and dispersive convection as that in the leachate. Two specific phenomena have been identified and considered in the model: (i) the early surface dissolution of the material which results in high Ca concentration and (ii) the late weak dissolution of Na and K giving rise to a long-term residual release. The intrinsic material parameters such as the initial concentrations in the pore water and solid phases were determined by applying equilibrium leaching tests and geochemical modelling. Diffusion coefficients for different elements and the late solubility of alkalines have been found to reach the same values in the four tests. The estimated values of the surface dissolution kinetic constant have shown a dependence on leachate hydrodynamics when the thickness of the degraded layer is nearly the same in the four tests (intrinsic parameter of the material). The competition between the four main dynamic processes, i.e. diffusion, convection, late dissolution, and surface dissolution, has been emphasized and compared in the four leaching tests: the hydrodynamic dispersion and the residence time had no effect on the leaching behaviour of alkalines, which is controlled by diffusion, whereas the behaviour of calcium (a major element of the material) was strongly influenced. This has significant effects on eluate pH values and on the concentration of Pb (the monitored pollutant). The model was then applied to simulate a landfill scenario in the case of a stabilized/solidified incinerator residue containing heavy metals and chloride. A high rain infiltration level and the use of small blocs are favourable conditions for enhanced pollutant release.  相似文献   
16.
Environmental Science and Pollution Research - There is increasing interest in understanding the role of air pollution as one of the greatest threats to human health worldwide. Nine of 10...  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