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431.
432.
Three annual motorcycle races on the Johnson Valley-Parker course in California's Mojave Desert have resulted in conspicuous modifications of soil and vegetation in a Wilderness Study Area (WSA) and in other lands of high resource values. The extent of damage caused by the races, which have involved fewer than 400 participants, exceeded the expectations of the managing agency by 360%–640% and the allowable limits imposed by the agency by 40%–76%. After three races, no resource monitoring results have been obtained by which compliance with the regulations for interim management of the Wilderness Study Area may be judged. Designation of the remaining parts of the course on lands of high resource value was based on criteria subsequently determined by a federal court to be in violation of regulations derived from two Executive Orders.  相似文献   
433.
ABSTRACT: The pressure on water resources from energy resource development and transformation is likely to be greater in the future than it has been in the past. A rational resolution of the political problems that this situation will generate requires that: 1) planning based on predictions of future energy supply and demand be replaced by scenario, or “what if?” analysis; 2) full attention be paid to the uncertainties in per-unit-energy water requirements; 3) suitable stochastic measures of water availability be used to compare water supply with water demand; 4) realistic ecological criteria, and other alternative use criteria, be developed for estimating impacts of water withdrawn or consurned for energy development; 5) human consequences of ecological impaccts are described in a manner that will allow the political process to intervene in an optimum manner to allocate water resources.  相似文献   
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The transfer 137Cs, 238Pu, 239/240Pu and 241Am to sheep which graze a saltmarsh in the Esk estuary, 7 km south of the sellafield reprocessing plant in west Cumbria (UK), has been estimated.The concentrations of gamma-emitting radionuclides and of 238Pu, 239/240Pu and 241Am were measured in liver, lung, muscle, kidney and bone from saltmarsh ewes and lambs. 137Cs concentrations in the soft tissues were similar in liver, lung and muscle but were consistently higher in kidney and much lower in bone. The highest concentration of the transuranics was found in liver.Transfer coefficients and concentration factors were calculated for both ewes and lambs. The concentration of 137Cs in the tissues of 5-month old lambs was higher than in those of their mothers. Therefore, a higher transfer coefficient was obtained for lamb muscle (1·8 × 10?1 d kg?1) than for ewe muscle (6·4 × 10?2 d kg?1). Concentration factors were consistently higher for 137Cs than for the transuranics.  相似文献   
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An ability to predict radionuclide activity concentrations in biota is a requirement of any method assessing the exposure of biota to ionising radiation. Within the ERICA Tool fresh weight whole-body activity concentrations in organisms are estimated using concentration ratios (the ratio of the activity concentration in the organism to the activity concentration in an environmental media). This paper describes the methodology used to derive the default terrestrial ecosystem concentration ratio database available within the ERICA Tool and provides details of the provenance of each value for terrestrial reference organisms. As the ERICA Tool considers 13 terrestrial reference organisms and the radioisotopes of 31 elements, a total of 403 concentration ratios were required for terrestrial reference organisms. Of these, 129 could be derived from literature review. The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches.  相似文献   
439.
In locating noxious facilities, such as a trash disposal plant or a hazardous waste disposal incinerator, the host community frequently incurs all the costs while other communities in the region receive the benefits. We propose a mechanism for sharing the benefits with the potential loser. Each community submits a sealed bid indicating the minimum amount it would require to host the facility. The site providing the lowest bid obtains the facility and receives its bid as compensation. This compensation is financed by the other communities. If there are N candidate communities, then each of the other communities would pay 1/(N − 1) of their acceptance bid. A series of controlled laboratory experiments show that the outcomes of this low-bid auction come close to predictions from a theoretical model based on maxi-min rules. Equity and efficiency considerations also are discussed in the context of the noxious facility problem.  相似文献   
440.
The market rate of return on private investment is often used as the discount rate when conducting cost-benefit analysis (CBA) of public projects. I argue that the decision to invest pits current consumption against future consumption, both of which accumulate to the private decision maker. Public projects, on the other hand, provide benefits that accrue to society in general. To examine the appropriateness of discount rates based on returns to private investment, this paper considers lab experiments designed to test whether individuals discount personal and social benefits at different rates. Personal benefits are captured through personal monetary payments, while social benefits are captured through anonymous donations to charitable organizations. I jointly elicit time and risk preferences and find that subjects discount charitable contributions at significantly lower rates than personal payments.  相似文献   
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