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281.
Reuse of by-products in road construction is most often environmentally evaluated from the narrow perspective of the material itself, i.e. the material level. In this article, we argue that the current mainstream environmental evaluation of reuse of by-products in road construction should use wider system boundaries. In order to illustrate the importance of system boundaries to the final result, three additional levels that complement the material level, are applied to the environmental evaluation of reuse of by-products. In total these four levels of evaluation are, firstly, the material itself, mainly studied by leaching tests, secondly, the road environment studied by substance flow analysis, furthermore, a narrow life-cycle perspective and, finally, the industrial system level that addresses the reuse of by-products in a broader sense. Methods and tools applied to different levels emphasise different environmental aspects and consequently they are appropriate for addressing different questions. However, especially for the evaluation of environmental aspects on the industrial system level, there is a need to develop the methods. To apply these four levels to the evaluation would broaden the knowledge about the environmental impacts of the reuse of by-products. We argue that current leaching tests have to be complemented by the broader system boundaries used in substance flow studies and in life-cycle assessments in order to discuss the use of resources and environmental impacts from a wider perspective. 相似文献
282.
Lewis C. Linker Robin Dennis Gary W. Shenk Richard A. Batiuk Jeffrey Grimm Ping Wang 《Journal of the American Water Resources Association》2013,49(5):1025-1041
Application of integrated Chesapeake Bay models of the airshed, watershed, and estuary support air and water nitrogen controls in the Chesapeake. The models include an airshed model of the Mid‐Atlantic region which tracks the estimated atmospheric deposition loads of nitrogen to the watershed, tidal Bay, and adjacent coastal ocean. The three integrated models allow tracking of the transport and fate of nitrogen air emissions, including deposition in the Chesapeake watershed, the subsequent uptake, transformation, and transport to Bay tidal waters, and their ultimate influence on Chesapeake water quality. This article describes the development of the airshed model, its application to scenarios supporting the Chesapeake Total Maximum Daily Load (TMDL), and key findings from the scenarios. Key findings are that the atmospheric deposition loads are among the largest input loads of nitrogen in the watershed, and that the indirect nitrogen deposition loads to the watershed, which are subsequently delivered to the Bay are larger than the direct loads of atmospheric nitrogen deposition to Chesapeake tidal waters. Atmospheric deposition loads of nitrogen deposited in coastal waters, which are exchanged with the Chesapeake, are also estimated. About half the atmospheric deposition loads of nitrogen originate from outside the Chesapeake watershed. For the first time in a TMDL, the loads of atmospheric nitrogen deposition are an explicit part of the TMDL load reductions. 相似文献
283.
This paper aims to contribute to the ongoing debate on the use of resource accounting tools in regional policy-making. The Northern Limits project applied material flow analysis (MFA) and ecological footprinting (EF) to regional policy-making in Northern Ireland over a number of years. The early phase of the research informed the regions first sustainable development strategy which was published in 2006 with key targets relating to the EF and improving the resource efficiency of the economy. Phase II identified the next steps required to address data availability and quality and the use of MFA and EF in providing a measurement and monitoring framework for the strategy and the development of the strategy implementation plan. The use of MFA and EF in sustainable regional policy-making and the monitoring of its implementation is an ongoing process which has raised a number of research issues which can inform the ongoing application and development of these and other resource accounting tools to within Northern Ireland, provide insights for their use in other regions, and help set out the priorities for research to support this important policy area. 相似文献
284.
BFR-governmental testing programme 总被引:4,自引:0,他引:4
As a consequence of results from recent studies, indicating increasing concentrations of polybrominated diphenyl ethers (PBDEs) in a wide range of environmental samples, governments have begun to consider the need to restrict the production and use of this compound group. Within the EU, it has been decided to cease production and use of the pentamix PBDE formulation, and the industry has already moved to alternative compounds. In Asia, the Japanese industries restrict voluntarily the production and use of polybrominated biphenyls (PBBs), hexabromodiphenyl ether and tetrabromodiphenyl ether. In North America, no such decisions have been taken as yet, and production of the pentamix continues. Ecolabelling and ecological product declarations are also being used in order to accelerate the phase-out process of brominated flame retardant (BFR). They restrict to different degrees the use of BFR in plastic, textiles, flexible floorings and insulating materials. Many governments have also initiated studies intended to provide more information on the octamix and decamix PBDE formulations, and the replacement compounds hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA), regarding their significance as environmental contaminants and to inform the need for further regulatory action. These studies are summarised below. 相似文献
285.
Robin G. Adams 《Natural resources forum》1990,14(2):90-96
In the 1980s, the basic strategies of the major integrated aluminium companies have been to emphasize added investment in downstream activities at the expense of investment in smelting and raw material supply. The paper examines the rationale for such investment strategies, explores the advantages and disadvantages of downstream investment and presents projections of future demand and capacity in the industry. Overall, the industry appears to be in good shape until the mid-1990s when demand is likely to exceed currently projected capacity. 相似文献
286.
Summary By measuring daily intake of food, we compared the cost of incubation for small and large clutches in adult Bengalese finches (Lonchura striata var. domestica). Natural clutches of captive finches were experimentally manipulated to produce two egg or six egg clutches. While incubating large clutches, parents ate significantly more food and took longer to hatch their first egg than did the same birds when provided with small clutches. This supports the hypothesis that the cost of incubation increases with clutch size. This cost should influence other energy allocation decisions in birds such as determination of clutch size and parental investment decisions. 相似文献
287.
In memoriam of Bernt Linzen 相似文献
288.
Several small populations of Hawaiian monk seals ( Monachus schauinslani ) exhibit male-biased adult sex ratios and "mobbing," an aggressive behavior in which adult males injure and often kill adult females and immature seals of both sexes during mating attempts. Mobbing appears to be limiting the growth of some populations of this endangered species. The frequency of mobbing deaths appears to increase as a population's sex ratio becomes increasingly male-biased, although the exact relationship between these two variables (the mobbing response) is unknown. We developed a stochastic demographic model of a small Hawaiian monk seal population using several different assumptions about the mobbing response. We used the model to explore the origins of male-biased sex ratios in monk seal populations and to determine whether it was possible, given the lack of data on the mobbing response, to evaluate the probable effects of alternative management strategies to address the mobbing problem. Small populations (100 to 200 seals) and those with slower growth rates were more likely to develop male-biased adult sex ratios. Almost all of our modeling scenarios supported the immediate removal of males from populations where mobbing occurs. Our conclusions were relatively unaffected when the assumptions regarding the mobbing response were varied. Thus, a model was helpful even when apparently crucial data were unavailable. 相似文献
289.
Summary. We describe the use of pieces of silicone tubing
to analyse the mandibular gland components of queen and
worker honeybees and show that these compounds can be
efficiently trapped on bis(trimethylsilyl)trifluoroacetamide
(BSTFA) treated pieces of tubing. The use of this technique
rather than that of solid phase microextraction (SPME) techniques
with commercially available fibres that have been
shown to be efficient at sampling secretions from the cuticle
of insects, is necessitated by a requirement for collection of
large sample numbers in a short space of time or for
sampling in the field. The technique may be generalised for
use with semiochemicals of low volatility in other insect
communciation systems. 相似文献
290.