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261.
262.
RIVPACS models for predicting the expected macroinvertebrate fauna and assessing the ecological quality of rivers 总被引:4,自引:0,他引:4
The European Union Water Framework Directive recognises the need for and value of biological monitoring. This paper reviews the modelling approach known as River Invertebrate Prediction and Classification System (RIVPACS
for assessing the ecological quality of river sites using macroinvertebrate sampling. The RIVPACS philosophy is to develop statistical relationships between the fauna and the environmental characteristics of a large set of high quality reference sites which can be used to predict the macroinvertebrate fauna to be expected at any site in the absence of pollution or other environmental stress. The observed fauna at new test sites can then be compared with their site-specific expected fauna to derive indices of ecological quality. All methodological decisions in any such model development have implications for the reliability, precision and robustness of any resulting indices for assessing the ecological quality and ecological grade (‘status’) of individual river stretches. The choice of reference sites and environmental predictor variables, the site classification and discrimination methods, the estimation of the expected fauna, and indices for comparing the agreement, or lack of it, between the observed and expected fauna, are all discussed. The indices are assessed on the reference sites and on a separate test set of 340 sites, which are subject to a wide range of types and degrees of impairment. 相似文献
263.
264.
Professor S. Openshaw Mike Coombes 《Journal of Environmental Planning and Management》1991,34(1):50-54
Policy indicators applied at a national scale can have considerable financial impact for resource allocations to individual counties, especially if there are extreme local factors. This article develops arid explores a new measure of population dispersal and sparsity and discusses the impact of this indicator in a variety of locations, by using GIS techniques. 相似文献
265.
Mike Danson 《Journal of Environmental Planning and Management》1991,34(2):89-95
This paper describes the recent economic history of the Scottish economy and uses a synthesised theory of labour market segmentation and the dual economy to identify the origins of the relative decline of Scottish industry and labour over the period, critically evaluating the role of the SDA and of government policy in general. Incorporating the impacts of takeover and merger of indigenous companies, the promotion of the branch plant economy, the selective effects of emigration and training schemes, and the reliance on small and medium sized companies to regenerate the economies of city‐regions, an analysis based on the importance of the centre‐periphery relations of monopoly capitalism for the Scottish economy is undertaken. 相似文献
266.
Robert Starr 《Natural resources forum》1994,18(1):63-68
Foreign companies interested in natural resources ventures in republics of the Commonwealth of Independent States must contend with a legal, regulatory and tax environment that is particularly fluid. The approval process for joint ventures, production sharing and export agreements (particularly for natural resources) is complex. Legislation in most CIS countries falls short of adequately addressing investors' concerns or lacks clear guidance on many key issues, such as conditions under which a state enterprise can enter into new business arrangements under current privatization laws. Among other conditions that act as a constraint to investment projects are lack of a sufficiently convertible currency in each CIS country and complex regimes of currency regulation; the absence of financing techniques that are common in market economies (ie secured lending); the need to scrutinize the validity and enforceability of any locally available guarantees and a reluctance by financial institutions to participate in projects in CIS countries (often because they have considerable difficulty assessing the viability of projects). These problems demand an extraordinary commitment in terms of effort and perseverance from potential investors, as compared to projects in other areas of the world. This paper cites the key negotiating issues and transactions that need to be structured with care by a prudent investor. 相似文献
267.
The promotion of renewable energy during the last decade did not result in widescale application of the technology. In many cases, technologies were promoted before they were commercially viable or were inappropriately selected for the particular end-use application. In other cases, a lack of local technical expertise and support infrastructure was absent to sustain the technology once it had been placed in the field. There was also a loss of donor interest and funding for renewables concomitant with the decline in oil prices. This paper attempts to summarize lessons learned from this decade of experience with renewable energy and to offer criteria and suggestions for future activities in transferring renewable energy technology. 相似文献
268.
Mike A. Acheampong Kannan Paksirajan Piet N. L. Lens 《Environmental science and pollution research international》2013,20(6):3799-3811
The physical and chemical qualities of the process effluent and the tailings dam wastewater of AngloGold-Ashanti Limited, a gold mining company in Ghana, were studied from June to September, 2010. The process effluent from the gold extraction plant contains high amounts of suspended solids and is therefore highly turbid. Arsenic, copper and cyanide were identified as the major pollutants in the process effluent with average concentrations of 10.0, 3.1 and 21.6 mg?L?1, respectively. Arsenic, copper, iron and free cyanide (CN?) concentrations in the process effluent exceeded the Ghana EPA discharge limits; therefore, it is necessary to treat the process effluent before it can be discharged into the environment. Principal component analysis of the data indicated that the process effluent characteristics were influenced by the gold extraction process as well as the nature of the gold-bearing ore processed. No significant correlation was observed between the wastewater characteristics themselves, except for the dissolved oxygen and the biochemical oxygen demand. The process effluent is fed to the Sansu tailings dam, which removes 99.9 % of the total suspended solids and 99.7 % of the turbidity; but copper, arsenic and cyanide concentrations were still high. The effluent produced can be classified as inorganic with a high load of non-biodegradable compounds. It was noted that, though the Sansu tailings dam stores the polluted effluent from the gold extraction plant, there will still be serious environmental problems in the event of failure of the dam. 相似文献
269.
Dimitris Dermatas Mike Dadachov Xiaoguang Meng 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1363-1372
Abstract Artificially contaminated (spiked) natural soils were solidified/stabilized using various combinations of commonly used additives, such as lime, cement, fly ash, activated carbon, and silica fume. The effectiveness of the solidification/stabilization (S/S) processes was evaluated based on experimental findings from compaction testing, unconfined compressive shear strength, and X-ray diffraction (XRD). Correlations of limited reliability between unconfined compressive strength and penetrometer and torvane measurements were derived. Results from XRD experiments indicated that certain organic contaminants (i.e., naphthalene and pyrene) might impact the S/S processes for a given combination of additives. The type and amount of organic contaminants also affected the pozzolanic reactions. Specifically, the absence or small peak intensity of pozzolanic product XRD patterns for a given combination of additives was a good indication that the type and the amount of organic contaminant present inhibited pozzolanic reactions. This phenomenon was tested and confirmed for actual field-contaminated samples. 相似文献