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301.
In a 1989 article, Ben Twight and Fremont Lyden compared the attitudes of national forest managers in the United States in 1981 with those of its major constituents to assess the extent to which the U.S. Forest Service was biased: were the beliefs and values of agency employees concerning resource management more representative of one of two major constituent groups, environmentalists and forest utilizers? The research tested Culhane's (Public Lands Politics: Interest Group Influence on the Forest Service and the Bureau of Land Management. Baltimore, Maryland: John Hopkins University Press. 1981) theory that the Forest Service occupies a middle ground in its attitudes relative to those of its environmental and utilization constituencies. They concluded that the agency did not; ideologically, district rangers were quite close to the Forest Service's utilizer constituency and relatively far from its environmentalist constituency. Given recent changes in the attitudes of Forest Services managers, the present study sought to answer the question: what do these changes reveal about the ideological position of the agency in 1981 vis a vis its position in 1990, and what are their implications for continuing concerns over the agency's representation of all interest groups? The response to survey questions of four groups—1990 district rangers and district rangers, environmentalists and forest utilizers in 1981—were combined for statistical comparison. Discriminant analyses were conducted to clarify the differences in the groups. Although the hypothesized bias of the Forest Service toward the traditional utilizer position was confirmed, the results also suggested that managers' values and attitudes had changed over the decade. The major issue underlying this bias—preservation versus utilization of resources—no longer adequately represented the agency's position, which has been fragmented into concerns with multiple issues. 相似文献
302.
In tests conducted for the Canadian government on sediment from Thunder Bay Harbour, Ontario, the BioGenesis washing process was demonstrated to be effective in remediating contaminated harbor sediments. Removal efficiencies for 16 polyaromatic hydrocarbons (PAHs) in concentrations exceeding 4,000 parts per million averaged 90 to 95 percent in pilot tests. These results are significant because, until now, washing processes have not proven effective in cleaning the small-size particles of silt and clay that make up most underwater sediments. In Thunder Bay, 81 percent of the particles were less than 38 microns (medium silt) in size. The tests on Thunder Bay sediment were conducted under the auspices of the Contaminated Sediment Treatment Technology Program of Environment Canada's Wastewater Technology Centre. Thunder Bay Harbour is one of 43 “areas of concern” identified by the International Joint Commission of Great Lakes Water Quality. 相似文献
303.
This research considers the question of changing environmental values within the leadership of firms responsible for the management of pollution as an unwanted byproduct. Information was obtained from a pair of surveys mailed to the chief executive officers (CEOs) of the 50 largest firms listed within the mining and manufacturing directories of Colorado, Montana, Utah, and Wyoming in 1976 and again in 1986. The authors found that industry CEOs were more supportive of environmental concerns in 1986 than 1976, suggesting that ecological values have become institutionalized to some extent. Yet, there is little indication that this attitudinal shift in environmental concern among CEOs has been accompanied by a willingness to spend a larger proportion of the company budget on pollution control or to improve working relationships with federal regulatory officials. 相似文献
304.
Charles H. Taylor Jim C. Loftis 《Journal of the American Water Resources Association》1989,25(4):715-726
ABSTRACT: The detection of gradual trends in water quality time series is increasing in importance as concern grows for diffuse sources of pollution such as acid precipitation and agricultural non-point sources. A significant body of literature has arisen dealing with trend detection in water quality variables that exhibit seasonal patterns. Much of the literature has dealt with seasonality of the first moment. However, little has been mentioned about seasonality in the variance, and its effect upon the performance of trend detection techniques. In this paper, eight methods of trend detection that arise from both the statistical literature as well as the water quality literature have been compared by means of a simulation study. Varying degrees of seasonality in both the variances and the means have been introduced into the artificial data, and the performances of these procedures are analyzed. Since the focus is on lake and ground water quality monitoring, quarterly sampling and short to moderate record lengths are examined. 相似文献
305.
J. Hugh. Ellis Charles S. ReVelle 《Journal of the American Water Resources Association》1988,24(2):435-447
ABSTRACT: A deterministic, separable, linear algorithm is presented for maximizing aggregate hydropower production. The method is iterative and amenable to solution using standard LP software. The utility of the technique is demonstrated using several test applications involving a hypothetical single-purpose hydropower reservoir and a monthly increment 20-year flow record from the Gunpowder River in Maryland. The separable linearized forms solved quickly using MPSX on a variety of IBM hardware: 3090-400 VF, 3084 QX, dual processor 4381-3, and an AT/370 personal computer. For comparison purposes, the original nonlinear nonseparable version of the model was also solved using MINOS. This yielded a value of aggregate hydropower marginally higher than that using MPSX. The separable, linearized methodology proved to be a useful and an efficient means of generating good starting points for MINOS. The use of these warm starts effected substantial reductions in MINOS execution times. 相似文献
306.
Doka SE McNicol DK Mallory ML Wong I Minns CK Yan ND 《Environmental monitoring and assessment》2003,88(1-3):53-101
Biological damage to sensitive aquatic ecosystems is among the most recognisable, deleterious effects of acidic deposition. We compiled a large spatial database of over 2000 waterbodies across southeastern Canada from various federal, provincial and academic sources. Data for zooplankton, fish, macroinvertebrate (benthos) and loon species richness and occurrence were used to construct statistical models for lakes with varying pH, dissolved organic carbon content and lake size. pH changes, as described and predicted using the Integrated Assessment Model (Lam et al., 1998; Jeffries et al., 2000), were based on the range of emission reductions set forth in the Canada/US Air Quality Agreement (AQA). The scenarios tested include 1983, 1990, 1994 and 2010 sulphate deposition levels. Biotic models were developed for five regions in southeastern Canada (Algoma, Muskoka, and Sudbury, Ontario, southcentral Québec, and Kejimkujik, Nova Scotia) using regression tree, multiple linear regression and logistic regression analyses to make predictions about recovery after emission reductions. The analyses produced different indicator species in different regions, although some species showed consistent trends across regions. Generally, the greatest predicted recovery occurred during the final phase of emission reductions between 1994 and 2010 across all taxonomic groups and regions. The Ontario regions, on average, were predicted to recover to a greater extent than either southcentral Québec or the Kejimkujik area of Nova Scotia. Our results reconfirm that pH 5.5–6.0 is an important threshold below which damage to aquatic biota will remain a major local and regional environmental problem. This damage to biodiversity across trophic levels will persist well into the future if no further reductions in sulphate deposition are implemented. 相似文献
307.
Ling M Rifai HS Newell CJ Aziz JJ Gonzales JR 《Journal of environmental monitoring : JEM》2003,5(1):126-134
An innovative methodology for improving existing groundwater monitoring plans at small-scale sites is presented. The methodology consists of three stand-alone methods: a spatial redundancy reduction method, a well-siting method for adding new sampling locations, and a sampling frequency determination method. The spatial redundancy reduction method eliminates redundant wells through an optimization process that minimizes the errors in plume delineation and the average plume concentration estimation. The well-siting method locates possible new sampling points for an inadequately delineated plume via regression analysis of plume centerline concentrations and estimation of plume dispersivity values. The sampling frequency determination method recommends the future frequency of sampling for each sampling location based on the direction, magnitude, and uncertainty of the concentration trend derived from representative historical concentration data. Although the methodology is designed for small-scale sites, it can be easily adopted for large-scale site applications. The proposed methodology is applied to a small petroleum hydrocarbon-contaminated site with a network of 12 monitoring wells to demonstrate its effectiveness and validity. 相似文献
308.
Charles J. Henny Lawrence J. Blus David J. Hoffman Robert A. Grove 《Environmental monitoring and assessment》1994,29(3):267-288
Mining and smelting at Kellogg-Smelterville, Idaho, resulted in high concentrations of lead in Coeur d'Alene (CDA) River sediments and the floodplain downstream, where American Kestrels (Falco sparverius), Northern Harriers (Circus cyaneus), Red-tailed Hawks (Buteo jamaicensis), Great Horned Owls (Bubo virginianus), and Western Screech-owls (Otus kennicotti) nested. Nestling American Kestrels contained significantly higher (P=0.0012) blood lead concentrations along the CDA River (0.24 µg/g, wet wt) than the nearby reference area (0.087 µg/g). A 35% inhibition of blood -aminolevulinic acid dehydratase (ALAD) in nestling Northern Harriers (P=0.0001), 55% in nestling American Kestrels (P=0.0001) and 81% in adult American Kestrels (P=0.0004) provided additional evidence of lead exposure in the CDA River population. In nestling American Kestrels and Northern Harriers, ALAD activity was negatively correlated with lead in blood. An earlier report on Ospreys (Pandion haliaetus) showed slightly less inhibition of ALAD than in American Kestrels, but no significant reduction in hemoglobin or hematocrit and no negative influence on production rates. The adult and nestling American Kestrels along the CDA River contained about twice as much blood lead as Ospreys during the same years (adult 0.46 vs. 0.20 µg/g, and nestling 0.24 vs. 0.09 µg/g), but adults showed a 7.5% reduction in hemoglobin (P=0.0356) and nestlings an 8.2% reduction in hemoglobin (P=0.0353) and a 5.8% reduction in hematocrit (P=0.0482). We did not observe raptor deaths related to lead, and although the production rate for American Kestrels was slightly lower along the CDA River, we found no significant negative relation between productivity and lead. Limited data on the other raptors provide evidence of exposure to lead along the CDA River. Several traits of raptors apparently reduce their potential for accumulating critical levels of lead which is primarily stored in bones of prey species.The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. 相似文献
309.
310.
Jae-Young Ko Charles A. S. Hall Luis G. López Lemus 《Environmental monitoring and assessment》1998,51(1-2):571-593
We examine trends from 1970 to the mid 1990's of some variables related to development and sustainability for Costa Rica, Korea, Mexico, the Netherlands and the United States: first, by calculating energy and agricultural efficiencies over time, second, by examining the environmental impacts of economic activities, and third, by estimating ecological footprints. We find that many "optimistic" arguments about sustainability have been misleading, and that there is little or no indication that we are becoming any more sustainable or even efficient. Total quality-corrected energy consumption has increased for all five countries and the renewable energy portion is decreasing. The efficiency of turning energy into both agricultural production and GDP has declined for all countries except for the US. In general, there is a remarkable linearity between resource use and economic and agricultural production over all countries and all years, suggesting severe biophysical constraints to sustainable objectives. On the other hand, per capita ecological footprints have decreased somewhat in Costa Rica, Mexico, and the United States, while national ecological footprints have tended to remain constant except for Korea. While there has been a reduction of specific pollutants in the United States, some of this has been achieved by exporting heavy manufacturing industries. We conclude that continued population and economic growth in each country is likely to make the achievement of any kind of sustainability increasingly unlikely. Sustainability, if that is desirable, requires a very different approach than what we have undertaken to date. 相似文献