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Option value is estimated for the Washakie Wilderness, northwest Wyoming, USA, using the contingent valuation technique. Consumer
surplus, the traditional measure of economic value, is estimated separately and compared with option value. Several populations
are tested, including Washakie visitors, Yellowstone National Park visitors, and residents from four metropolitan test markets:
Salt Lake City, Utah; Portland, Oregon; Nashville, Tennessee; and Orlando, Florida, USA. The average annual preservation option
value (consumer surplus) expressed by on-site wilderness visitors is $46.17 ($80.13), by urban residents is $9.70 ($8.97),
and by rural residents is $8.43 ($7.80). Four selected attributes are determined to be important in motivating option demand
for the Washakie, including existence value, bequest value, the desire for an on-site visit, and interest in securing the
visiting privileges of others. The results suggest that option value is important in wilderness valuation and that off-site
users account for a large part of the economic value of wilderness. 相似文献
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DRAGANA MUTAVDŽIĆ IVAN BRNARDIĆ MARIJA KAŠTELAN-MACAN 《Journal of environmental science and health. Part. B》2013,48(7):1085-1101
The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and α-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was ≥0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule. 相似文献
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Kenneth A. Barrick 《Environmental management》2010,45(1):192-202
Geyser basins provide high value recreation, scientific, economic and national heritage benefits. Geysers are globally rare,
in part, because development activities have quenched about 260 of the natural endowment. Today, more than half of the world’s
remaining geysers are located in Yellowstone National Park, northwest Wyoming, USA. However, the hydrothermal reservoirs that
supply Yellowstone’s geysers extend well beyond the Park borders, and onto two “Known Geothermal Resource Areas”—Island Park
to the west and Corwin Springs on the north. Geysers are sensitive geologic features that are easily quenched by nearby geothermal
wells. Therefore, the potential for geothermal energy development adjacent to Yellowstone poses a threat to the sustainability
of about 500 geysers and 10,000 hydrothermal features. The purpose here is to propose that Yellowstone be protected by a “Geyser
Protection Area” (GPA) extending in a 120-km radius from Old Faithful Geyser. The GPA concept would prohibit geothermal and
large-scale groundwater wells, and thereby protect the water and heat supply of the hydrothermal reservoirs that support Yellowstone’s
geyser basins and important hot springs. Proactive federal leadership, including buyouts of private groundwater development
rights, can assist in navigating the GPA through the greater Yellowstone area’s “wicked” public policy environment. Moreover,
the potential impacts on geyser basins from intrusive research sampling techniques are considered in order to facilitate the
updating of national park research regulations to a precautionary standard. The GPA model can provide the basis for protecting
the world’s few remaining geyser basins. 相似文献
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