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71.
Griffith JF Aumand LA Lee IM McGee CD Othman LL Ritter KJ Walker KO Weisberg SB 《Environmental monitoring and assessment》2006,117(1-3):335-344
During the summers of 2002 and 2004, in-stream integrated flow and concentration measurements for the total dissolved solids
in the Cheyenne River, South Dakota, USA was conducted in order to compare the obtained actual field measurements with the
predictions values made by the Bureau of Reclamation in the Environmental Impact Statement. In comparison to the actual field
measurements conducted in this study, The Bureau of Reclamation extension of a small database used in the analysis for the
impact of operations at the Angostura Unit over the past 50 years and into the future to predict the annual total dissolved
solid loadings doesn't represent the actual loading values and various conditions in the study area. Additional integrated
flow and concentration sampling is required to characterize the impact of the current Angostura Dam operations and Angostura
Irrigation District return flows on the Cheyenne River in different seasons of the year. 相似文献
72.
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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75.
John K. Stranlund Kanwalroop Kathy Dhanda 《Journal of Environmental Economics and Management》1999,38(3):267
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
76.
Kalkhoff SJ Lee KE Porter SD Terrio PJ Thurman EM 《Journal of environmental quality》2003,32(3):1025-1035
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