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101.
The EMAP program has been organized into three primary elements: Multi-Tier Design, Indicators, and Index Sites. The Index Sites program (DISPro - Demonstration Intensive Site Project) is the primary activity within the Index Sites element of EMAP. This project represents an inter-agency effort between EPA/ORD and DOI/NPS to develop a demonstration of an intensive site network of monitoring and research locations throughout the United States, utilizing the Nation's parklands as "outdoor laboratories." Twelve parks were selected to establish this demonstration. These 12 parks were selected because they are readily accessible, have a history of monitoring environmental information, and represent a broad spectrum of ecological communities. EMAP, through DISPro, is examining whether a "network" of sites existing within the parks can be used to address monitoring issues for global-scale environmental stressors (e.g., air pollution) as well as locale-specific stressors (e.g., air deposition, water-borne) and coordinated with cause-effect, issue-based research related to these environmental stressors. As a first activity, EPA will provide each of the sites with the instrumentation to monitor UV-B. The intent of the program is to initiate a consistent air monitoring program at each site to be followed by consistent monitoring within other media. The project will initiate research projects at all the sites (eventually) to examine the effects of environmental stressors of importance at each of the sites.  相似文献   
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The literature on noncompliant firms in transferable emissions permit systems offers little guidance to policymakers that must determine how to commit resources to monitor firms and punish violations in such systems. We consider how a budget-constrained enforcement authority that seeks to minimize aggregate noncompliance in a transferable emissions permit system should allocate its monitoring and enforcement efforts among heterogeneous firms. With a conventional model of firm behavior in a transferable permit system, we find that differences in the allocation of monitoring and enforcement effort between any two types of firms should be independent of differences in their exogenous characteristics.  相似文献   
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Herbicide concentrations in streams of the U.S. Midwest have been shown to decrease through the growing season due to a variety of chemical and physical factors. The occurrence of herbicide degradation products at the end of the growing season is not well known. This study was conducted to document the occurrence of commonly used herbicides and their degradation products in Illinois, Iowa, and Minnesota streams during base-flow conditions in August 1997. Atrazine, the most frequently detected herbicide (94%), was present at relatively low concentrations (median 0.17 microg L(-1)). Metolachlor was detected in 59% and cyanazine in 37% of the samples. Seven of nine compounds detected in more than 50% of the samples were degradation products. The total concentration of the degradation products (median of 4.4 microg L(-1)) was significantly greater than the total concentration of parent compounds (median of 0.26 microg L(-1)). Atrazine compounds were present less frequently and in significantly smaller concentrations in streams draining watersheds with soils developed on less permeable tills than in watersheds with soils developed on more permeable loess. The detection and concentration of triazine compounds was negatively correlated with antecedent rainfall (April-July). In contrast, acetanalide compounds were positively correlated with antecedant rainfall in late spring and early summer that may transport the acetanalide degradates into ground water and subsequently into nearby streams. The distribution of atrazine degradation products suggests regional differences in atrazine degradation processes.  相似文献   
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Environmental Science and Pollution Research - Improper disposal of animal waste is responsible for several environmental problems, causing eutrophication of lakes and rivers, nutrient overload in...  相似文献   
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