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981.
982.
This paper presents an aerosol generation technique developed to produce dry aerosol particles of various sizes from aqueous solutions of salt. The technique was tested with sodium chloride, lithium carbonate and uranyl acetate at various aqueous concentrations which produced particles in the size range of 0.13-1.37 microm Mass Median Diameter (MMD). The generated aerosols were acceptably monodisperse with a geometric standard deviation of 1.4-2. Both MMD and Mass Median Aerodynamic Diameter (MMAD) increased significantly (p<0.001) with increased concentration of the salt in solution. The technique can also be used to generate aerosols of different chemical species. The results obtained indicate that the system is convenient for use with various aerosol-forming materials, with a stable particle size distribution being maintained for a long period of steady operation. The technique was successfully applied in wind tunnel studies to simulate the release of submicron radioactive particles and their interception by crops, grass and tree canopies. The relevance and application of the technique in other areas of environmental assessment studies is discussed. 相似文献
983.
The purpose of this research was to explore the concept of an environmental racism claim through the use of several environmental
management tools. The EPAs Toxics Release Inventory, Cumulative Exposure Project, and the Los Angeles County Department of
Health Services' Hot Zone Census Tract Assessment were combined with racial and socioeconomic data to test claims that minorities
in South Central Los Angeles are disproportionately exposed to environmental lead. Multivariate analysis indicated that race
is strongly associated with the number of cases of elevated blood lead levels in South Central, irrespective of poverty status.
Proximity to point sources, a common focal point for studies of environmental racism, was not a contributing factor to health
outcomes. Proximity to transportation corridors was consistently the strongest indicator of environmental lead exposure, while
median home values were significantly and positively related to elevated blood lead levels. Implications for environmental
justice advocates and social and environmental scientists are discussed. 相似文献
984.
It is now widely accepted that members of the public should be involved in environmental decision-making. This has inspired
many to search for principles that characterize good public participation processes. In this paper we report on a study that
identifies discourses about what defines a good process. Our case study was a forest planning process in northern New England
and New York. We employed Q methodology to learn how participants characterize a good process differently, by selecting, defining,
and privileging different principles. Five discourses, or perspectives, about good process emerged from our study. One perspective
emphasizes that a good process acquires and maintains popular legitimacy. A second sees a good process as one that facilitates
an ideological discussion. A third focuses on the fairness of the process. A fourth perspective conceptualizes participatory
processes as a power struggle—in this instance a power play between local landowning interests and outsiders. A fifth perspective
highlights the need for leadership and compromise. Dramatic differences among these views suggest an important challenge for
those responsible for designing and carrying out public participation processes. Conflicts may emerge about process designs
because people disagree about what is good in specific contexts. 相似文献
985.
The production of large quantities of wastes globally has created a commercial activity involving the transfrontier shipments
of hazardous wastes, intended to be managed at economically attractive waste-handling facilities located elsewhere. In fact,
huge quantities of hazardous wastes apparently travel the world in search of “acceptable” waste management facilities. For
instance, within the industrialized countries alone, millions of tonnes of potentially hazardous waste cross national frontiers
each year on their way for recycling or to treatment, storage, and disposal facilities (TSDFs) because there is no local disposal
capacity for these wastes, or because legal disposal or reuse in a foreign country may be more environmentally sound, or managing
the wastes in the foreign country may be less expensive than at home. The cross-boundary traffic in hazardous wastes has lately
been under close public scrutiny, however, resulting in the accession of several international agreements and laws to regulate
such activities. This paper discusses and analyzes the most significant control measures and major agreements in this new
commercial activity involving hazardous wastes. In particular, the discussion recognizes the difficulties with trying to implement
the relevant international agreements among countries of vastly different socioeconomic backgrounds. Nonetheless, it is also
noted that global environmental agreements will generally be a necessary component of ensuring adequate environmental protection
for the world community—and thus a need for the careful implementation of such agreements and regulations. 相似文献
986.
Manoliadis OG 《Environmental management》2001,28(4):497-504
Irrigation management calls for objective criteria capable of representing the economy, reliability, and productivity of irrigation
systems. These criteria must be compatible with long-term sustainability and conservation goals. The criteria representing
the above goals are the economic effect of management on yield reduction, economic effect, and reliability referring to plant
growth and operation of the network. In this study environmental indices are introduced to express the above criteria in quantitative
terms. The inclusion of these indices at the farm and network level create a multicriteria framework for decision-making based
on composite programming. An experimental study was conducted during the irrigation periods of 1989 and 1990 in Chania, Greece,
concerning water delivered to 40 experimental plots, soil moisture content at the rootzone, and irrigation system operational
failures. The data collected in real time were used for the calculation of the corresponding environmental indices. The variation
in time and space is high and resulted in up to 62% of yield loss and low system performance (up to 7% of system temporal
reliability). The study indicated that environmental indices could be incorporated to select alternatives and also to develop
policies on water delivery. The final decision involves a trade-off analysis between cost of application and desired system
performance. Measures of both primary objectives can be obtained using environmental indices that represent system operation
aggregation at its basic levels (on farm and network). 相似文献
987.
We use spatial data representing transportation networks, elevation, stand height, and recreation use to construct and compare
models of recreation use patterns and visibility in a forest. The recreation use pattern model depicts use frequencies along
travel corridors. The visibility model quantifies visibility for all forest areas. We find that the models provide different
but complementary types of information. Forest managers who are involved in scheduling harvest operations and want to address
the visual concerns of forest visitors may benefit most from the visibility model. Managers who wish to know more about travel
patterns or to reroute forest visitors affected by operations may benefit from the use pattern model. A combination of the
two models has the highest potential for providing planning assistance in multiple-use forests. Both models may be able to
enhance visual resource management (VRM) systems already in use by providing spatially explicit recreation use and visibility
data. 相似文献
988.
Conservation strategies for effective land management of protected areas using an erosion prediction information system (EPIS) 总被引:1,自引:0,他引:1
This research demonstrates the predictive modeling capabilities of a geographic information system (GIS)-based soil erosion potential model to assess the effects of implementing land use change within a tropical watershed. The Revised Universal Soil Loss Equation (RUSLE) was integrated with a GIS to produce an Erosion Prediction Information System (EPIS) and modified to reflect conditions found in the mountainous tropics. Research was conducted in the Zenzontia subcatchment of the Río Ayuquíla, located within the Sierra de Manantlán Biosphere Reserve (SMBR), México. Expanding agricultural activities within this area will accentuate the already high rate of soil erosion and resultant sediment loading occurring in the Río Ayuquíla. Two land-use change scenarios are modeled with the EPIS: (1) implementation of soil conservation practices in erosion prone locations; and (2) selection of sites for agricultural expansion which minimize potential soil loss. Confronted with limited financial resources and the necessity for expedient action, managers of the SMBR can draw upon the predictive capacity of the EPIS to facilitate rapid and informed land-use planning decisions. 相似文献
989.
The literature guides environmental planning and, specifically, how to use ecological rehabilitation projects to achieve long-term
planning goals and landscape-scale environmental sustainability. There is, however, a perceived gap between principles in
the literature and the use of them by practitioners involved in smaller-scale ecological rehabilitation projects. Using interviews
with practitioners involved in 11 projects within the Regional Municipality of Waterloo, Ontario, Canada, we tested whether
practitioners used five principles for effective planning and implementation of ecological rehabilitation that we derived
from the literature. These five principles were: establishing political and ecological context, using ecologically appropriate
objectives and practices, using comparative multidisciplinary and cross-scale approaches, using adaptive planning and implementation,
and establishing good communication within and external to projects. Few projects followed all five principles, and practitioners
indicated that they used three more project-specific principles: obtaining political/social support, promoting projects and
changing attitudes about projects, and securing sufficient and persistent funding to maintain a project's life. While the
literature emphasizes that ecological rehabilitation is only effective if projects are coordinated on a watershed basis, most
practitioners focused solely on the goals of their specific project. The gap between literature and practice may arise because
most practitioners are new to the field of ecological rehabilitation and still are focused on the methods involved. Time pressures
force practitioners to obviate the literature and get projects started quickly, lest support evaporate. Complicating these
difficulties is decreased support from federal and provincial governments for large-scale environmental planning. It is unclear
whether ecological rehabilitation projects in Waterloo Region (at least) will ever become effective at promoting landscape-scale
ecological goals or remain smaller-scale stop-gaps. 相似文献
990.
For the last 20 years, human–wildlife conflicts have been rapidly increasing in towns. Although people want “greener” cities,
the expansion of disliked species causes problems that are difficult to manage and to reduce. The complexity of the numerous
factors involved in these human–wildlife relations needs the development of a comprehensive tool for urban planners. Today,
with the development of computers and geographical information systems, it is easier to analyze and combine different spatial
data as methods used for the management of risks in studies of natural hazards. Here we present a method for assessing and
mapping the risk in cases of human–wildlife conflict. An application to starling management in a town in western France will
show the efficiency of our methods to combine information given by a network of experts and to highlight higher risk sites.
The map of risk provides a spatial result useful for comprehension, communication between people and agencies, and public
education. 相似文献