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51.
The most important obstacle to solving diffuse pollution problems is that emissions are either unobservable or cannot be observed at a reasonable cost. Biophysical models may provide sufficient information to set a cost-effective emission tax. However, evidence from recent studies has shown that transaction costs for emission-based policies are higher per hectare than for input-based policies. An economic model of agriculture for the Kennet catchment in south-east England shows that, when transaction costs are accounted for, an input tax is more efficient than an emission tax over a range of emission standards. This result has policy implications in that it indicates, first, that economists' policy recommendations should account for transaction costs, and, secondly, that the standard advice that emission-based policies are superior may be wrong where transaction costs differ substantially between emission- and input-based policies. 相似文献
52.
Charles M. Buchanan Debra Dorschel Robert M. Gardner Ron J. Komarek Andrew J. Matosky Alan W. White Matthew D. Wood 《Journal of Polymers and the Environment》1996,4(3):179-195
In this account, we report our findings on blends of cellulose acetate having a degree of substitution (DS) of 2.49 (CA2.5) with a cellulose acetate having a DS of 2.06 (CA2.0). This blend system was examined over the composition range of 0–100% CA2.0 employing both solvent casting of films (no plasticizer) and thermal processing (melt-compressed films and injection molding) using poly(ethylene glycol) as a common plasticizer. All thermally processed blends were optically clear and showed no loss in optical quality after storage for several months. Thermal analysis and measurement of physical properties indicate that blends in the middle composition range are partially miscible, while those at the ends of the composition range are miscible. We suggest that the miscibility of these cellulose acetate blends is influenced primarily by the monomer composition of the copolymers. Bench-scale simulated municipal composting confirmed the biodestructability of these blends and indicated that incorporation of a plasticizer accelerated the composting rates of the blends.In vitro aerobic biodegradation testing involving radiochemical labeling conclusively demonstrated that both the lower DS CA2.0 and the plasticizer significantly enhanced the biodegradation of the more highly substituted CA2.5.While this work was in progress, Robert Gardner was struck with cancer and died on June 6, 1995. This paper is dedicated to his memory and to his contributions as a friend and colleague. 相似文献
53.
54.
Everett M. White James N. Dornbush 《Journal of the American Water Resources Association》1988,24(2):269-273
ABSTRACT: Wastewater from a municipal treatment plant was applied in rapid infiltration basins for four years to determine a poorly drained soils effectiveness in removing influent N and P and the soil changes that might limit their removal. About half the total PO4-P lost from the influent was sorbed in the upper 91 cm of the soil and the other half was sorbed by the soil below the perforated pipe, which was used to drain the basins and collect the effluent for analysis. Drying of the basin soils converted more sorbed PO4-P to Ca phosphates but the total sorbed was about the same. The in. fluent N decreased, probably by volatilization, because the two basins with surface soil lost soil N rather than gained soil N. The soil total Ca, Mg, and K contents did not change significantly but Na increased slightly. Changes in the physical characteristics of the soils were slight and would have little effect on the longevity of a rapid infiltration basin. 相似文献
55.
E. M. White 《Journal of the American Water Resources Association》1983,19(4):649-653
ABSTRACT A stepwise multiple regression was used to evaluate the relative importance of antecedent-, event-, and high-intensity-precipitation amounts; runoff volume; and precipitation nutrient contents and concentrations in determining nutrient losses in runoff. Plots were fertilized at high, medium, and low rates and had cultivation ridges oriented up-and-down slope or on the contour. Runoff volume was the important factor in determining the loss of NO3, soluble PO4, total PO4, and soluble K ions in runoff from fallow, corn, or soybean plots. NH4-N loss was controlled mainly by the precipitation content and antecedet precipitation since fertilizer had been applied. Nutrient losses were greater from plots fertilized at the high rate and from plots with cultivation ridges oriented up-and-down slope rather than on the contour. 相似文献
56.
Jeffery J. Himmelberger Samuel J. Ratick Allen L. White 《Environmental management》1991,15(5):647-658
This article analyzes the recent negotiations connected with siting 24 solid-waste landfills in Wisconsin. We examine the
association between the type and amount of compensation paid to host communities by facility developers and the size of facilities,
certain facility characteristics, the timing of negotiated agreements, the size of the host community, and the socioeconomic
status of the host area. Our findings suggest that the level of compensation after adjusting for landfill capacity is positively
associated with the percentage of total facility capacity dedicated to host community use, positively associated with the
percentage of people of the host area who are in poverty, and larger for public facilities that accept municipal wastes. Other
explanatory variables we examined, whose association with levels of compensation proved statistically insignificant, were
facility size, facility status (new vs expansion), facility use (countyonly vs multicounty), timing of negotiation, host community
size, and the host area education level, population density, and per capita income. We discuss the policy implications of
our principal findings and future research questions in light of the persistent opposition surrounding the siting of solid-waste
and other waste-management facilities. 相似文献
57.
ABSTRACT: Several methods for synthetic unit hydrographs are available in the literature. Most of these methods involve the hand fitting of a curve over a set of a few hydrograph points, which can sometimes be a subjective task. Besides, the user often finds it difficult or simply neglects to adjust the generated unit graph to a runoff volume of one unit (inch, cm, or mm). It is the purpose of this paper to present to the design hydrologist a simple method to fit a smooth gamma distribution over a single point specified by the unit hydrograph peak and the time to peak with a guaranteed unit depth of runoff. 相似文献
58.
Using Ion-Exchange Resins to Study Soil Response to Experimental Watershed Acidification 总被引:1,自引:0,他引:1
Szillery JE Fernandez IJ Norton SA Rustad LE White AS 《Environmental monitoring and assessment》2006,116(1-3):383-398
Ion-exchange resins (IER) offer alternative approaches to measuring ionic movement in soils that may have advantages over
traditional approaches in some settings, but more information is needed to understand how IER compare with traditional methods
of measurement in forested ecosystems. At the Bear Brook Watershed in Maine (BBWM), one of two paired, forested watersheds
is treated bi-monthly with S and N (28.8 and 25.2kgha−1yr−1 of S and N, respectively). Both IER and ceramic cup tension lysimeters were used to study soil solution responses after ∼11
years of treatment. Results from both methods showed treatments resulted in the mobilization of base cations and Al, and higher
SO4—S and inorganic N in the treated watershed. Both methods indicated similar differences in results associated with forest
type (hardwoods versus softwoods), a result of differences in litter quality and atmospheric aerosol interception capacity.
The correlation between lysimeter and IER data for individual analytes varied greatly. Significant correlations were evident
for Na (r=0.75), Al (r=0.65), Mn (r=0.61), Fe (r=0.57), Ca (r=0.49), K (r=0.41) and NO3—N (r=0.59). No correlation was evident between IER and soil solution data for NH4—N and Pb. Both IER and soil solution techniques suggested similar interpretations of biogeochemical behavior in the watershed. 相似文献
59.
Gu B Watson DB Wu L Phillips DH White DC Zhou J 《Environmental monitoring and assessment》2002,77(3):293-309
Zero-valent iron (Fe0)-based permeable reactive barriertreatment has been generating great interest for passivegroundwater remediation, yet few studies have paid particularattention to the microbial activity and characteristics withinand in the vicinity of the Fe0-barrier matrix. The presentstudy was undertaken to evaluate the microbial population andcommunity composition in the reducing zone of influence byFe0 corrosion in the barrier at the Oak Ridge Y-12 Plantsite. Both phospholipid fatty acids and DNA analyses were usedto determine the total microbial population and microbialfunctional groups, including sulfate-reducing bacteria,denitrifying bacteria, and methanogens, in groundwater andsoil/iron core samples. A diverse microbial community wasidentified in the strongly reducing Fe0 environment despitea relatively high pH condition within the Fe0 barrier (up topH 10). In comparison with those found in the backgroundsoil/groundwater samples, the enhanced microbial populationranged from 1 to 3 orders of magnitude and appeared to increase from upgradient of the barrier to downgradient soil. Inaddition, microbial community composition appeared to change overtime, and the bacterial types of microorganismsincreased consistently as the barrier aged. DNA analysisindicated the presence of sulfate-reducing and denitrifyingbacteria in the barrier and its surrounding soil. However, theactivity of methanogens was found to be relatively low,presumably as a result of the competition by sulfate/metal-reducing bacteria and denitrifying bacteria because of the unlimited availability of sulfate and nitrate in the site groundwater. Results of this study provide evidenceof a diverse microbial population within and in the vicinity ofthe iron barrier, although the important roles of microbial activity, either beneficially or detrimentally, on the longevityand enduring efficiency of the Fe0 barriers are yet to be evaluated. 相似文献
60.
Incorporating natural capital into economy-wide impact analysis: a case study from Alberta 总被引:1,自引:0,他引:1
Patriquin MN Alavalapati JR Adamowicz WL White WA 《Environmental monitoring and assessment》2003,86(1-2):149-169
Traditionally, decision-makers have relied on economic impactestimates derived from conventional economy-wide models. Conventional models lack the environmental linkages necessary for examining environmental stewardship and economic sustainability, and in particular the ability to assess the impact of policies on natural capital. This study investigatesenvironmentally extended economic impact estimation on a regionalscale using a case study region in the province of Alberta knownas the Foothills Model Forest (FMF). Conventional economic impactmodels are environmentally extended in pursuit of enhancingpolicy analysis and local decision-making. It is found that theflexibility of the computable general equilibrium (CGE) modelingapproach offers potential for environmental extension, with a solid grounding in economic theory. The CGE approach may be the tool of the future for more complete integrated environment andeconomic impact assessment. 相似文献