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91.
Monthly stream water calcium and Gran alkalinity concentration data from 11 sub-catchments of the Nether Beck in the English Lake District have been used to appraise the transferability of the Scottish, River Dee-based G-BASH model. Readily available riparian zone geochemistry and flow paths were used initially to predict minimum and mean stream water concentrations at the Nether Beck, based on calibration equations from the River Dee catchment data. Predicted values significantly exceeded observed values. Differences in runoff between the two areas, leading to a dilution effect in the Nether Beck, explained most of the difference between observed and predicted values. Greater acid deposition in the Lake District also reduced stream water Gran alkalinity concentrations in that area. If regional differences in precipitation, evapotranspiration and pollutant deposition are incorporated into the model, it may then be used reliably to predict catchment susceptibility to acidification over a wide regional (national) scale.  相似文献   
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Integrated catchment management (ICM) was introduced as state policy in 1988 to overcome land and water degradation in Western Australia (WA). Key elements of ICM are cooperation among state and local governments and landholders; involvement of landholders and local communities in identification of issues and solutions; and, agreement on common objectives. This study identifies the issues that led to the adoption of integrated catchment management in Western Australia, outlines its main characteristics, and reviews the progress and problems encountered during its initial implementation. ICM has generally been accepted and endorsed in WA. However, differences of opinion have emerged regarding exactly what it means and how it should be applied. Designing ideal organizational structures for ICM is not sufficient for it to be effective. Ultimately, people have to make ICM function, and therefore it is essential that priority be given to cultivating the good will and trust necessary for ICM to work well. ICM also requires a long-term perspective and appreciation that it requires many people and agencies to move out of current “comfort zones.” As a result, initial implementation of ICM usually will encounter turbulence and debate.  相似文献   
94.
A set of peat column experiments was used to determine the transport potential of lead (Pb) and diesel range organics (DRO) in palustrine slope wetlands near Juneau, AK. This project is important to southeast Alaskan communities because limited land resources are forcing development of regional wetlands. This study was instigated by concerns that proposed modifications to a nearby rifle range using DRO-contaminated soil posed a potential risk to an anadromous fish-bearing stream 250 m from the site. Three pairs of peat columns were extracted from the rifle range for analysis, one pair along and two pairs across the natural bedding planes of the soil. One column in each pair was spiked with Pb and DRO and the other was used as a control. Approximately 1-year worth of water (171 cm) was passed through each column and leachate was collected at regular intervals. The results showed that substantial DRO transport only occurred along the bedding planes. Leads was surprisingly mobile, both along and across the bedding planes with estimated soil-water partition coefficients several orders of magnitude lower than commonly published values, probably because the peat was heavily Pb-loaded by lead from bullets and because the peat's acidic, organic-rich environment enhanced Pb mobility. The chemical outflow behavior agreed with a simple macropore transport model. These results underscore the need for caution when developing regional wetlands.  相似文献   
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Summary In an effort to explain the benefit of therapeutic use of electromagnetic fields (EMF) a systemic effect has been proposed by us. To assess the efficacy of this approach, an objective biochemical approach was developed. Ten patients with Reflex Sympathetic Dystrophy (RSD) were clinically evaluated, and lymphocytes were isolated from their blood samples obtained before and after exposure of the uninvolved limb to an EMF. Utilizing a SpectraCell method that includes radio labeled molecules and protein-free media for culturing the lymphocytes, an elevation of the content of fructose, serine, glycine, and calcium cellular metabolic uptake were found following in the culture to EMF in comparison with non-exposed lymphocytes (p < 0.01). In addition, the pain level was determined by a conventional visual analogue scale (VAS) before and after EMF exposure, evidencing a significant pain relief. Specifically, after exposure to 120 pps semi sinewave, 1500Gauss EMF, generated by a THERAMAGledR device, an improvement in the flexibility of the limb and a reduction in swelling of the affected extremity were detected clinically. These findings are in concert with the new hypothesis that, with relief of pain, lymphocytes are predominately altered in their cell cycle from M phase to S phases associated with increased structuring of intracellular water. A consideration of the basic understanding of the role lymphocytes may be inferred from this preliminary study. An extensive review of the literature on the basic science and therapeutic use of magnetic fields in humans is provided in an attempt to understand the relevance of magnetic therapy of specific pain syndromes.  相似文献   
97.
As natural resource management agencies and conservation organizations seek guidance on responding to climate change, myriad potential actions and strategies have been proposed for increasing the long-term viability of some attributes of natural systems. Managers need practical tools for selecting among these actions and strategies to develop a tailored management approach for specific targets at a given location. We developed and present one such tool, the participatory Adaptation for Conservation Targets (ACT) framework, which considers the effects of climate change in the development of management actions for particular species, ecosystems and ecological functions. Our framework is based on the premise that effective adaptation of management to climate change can rely on local knowledge of an ecosystem and does not necessarily require detailed projections of climate change or its effects. We illustrate the ACT framework by applying it to an ecological function in the Greater Yellowstone Ecosystem (Montana, Wyoming, and Idaho, USA)-water flows in the upper Yellowstone River. We suggest that the ACT framework is a practical tool for initiating adaptation planning, and for generating and communicating specific management interventions given an increasingly altered, yet uncertain, climate.  相似文献   
98.
Fine particulate matter (PM2.5), source fingerprints and their contributions have been measured and reported previously at Hanoi, Vietnam, from 25 April 2001 to 31 December 2008. In this study back trajectories are used to identify long range transport into Hanoi for two of these sources, namely, windblown dust (Soil) from 12 major deserts in China and emissions from 33 coal fired power plants (Coal) in Vietnam and China. There were 28 days of extreme Soil events with concentrations greater than 6 μg m?3 and 25 days of extreme Coal with concentrations greater than 30 μg m?3 from a total of 748 sampling days during the study period. Through the use of back trajectories it was found that long range transport of soil from the Taklamakan and Gobi desert regions (more than 3000 km to the north west) accounted for 76% of the extreme events for Soil. The three local Vietnamese power stations contributed to 15% of the extreme Coal events, while four Chinese power stations between 300 km and 1700 km to the north-east of Hanoi contributed 50% of the total extreme Coal events measured at the Hanoi sampling site.  相似文献   
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100.
The results of a 21 month sampling program measuring tritium in tree transpirate with respect to local sources are reported. The aim was to assess the potential of tree transpirate to indicate the presence of sub-surface seepage plumes.Transpirate gathered from trees near low-level nuclear waste disposal trenches contained activity concentrations of 3H that were significantly higher (up to ∼700 Bq L−1) than local background levels (0-10 Bq L−1). The effects of the waste source declined rapidly with distance to be at background levels within 10s of metres. A research reactor 1.6 km south of the site contributed significant (p < 0.01) local fallout 3H but its influence did not reach as far as the disposal trenches.The elevated 3H levels in transpirate were, however, substantially lower than groundwater concentrations measured across the site (ranging from 0 to 91% with a median of 2%). Temporal patterns of tree transpirate 3H, together with local meteorological observations, indicate that soil water within the active root zones comprised a mixture of seepage and rainfall infiltration. The degree of mixing was variable given that the soil water activity concentrations were heterogeneous at a scale equivalent to the effective rooting volume of the trees. In addition, water taken up by roots was not well mixed within the trees. Based on correlation modelling, net rainfall less evaporation (a surrogate for infiltration) over a period of from 2 to 3 weeks prior to sampling seems to be the optimum predictor of transpirate 3H variability for any sampled tree at this site.The results demonstrate successful use of 3H in transpirate from trees to indicate the presence and general extent of sub-surface contamination at a low-level nuclear waste site.  相似文献   
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