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121.
Curtis G. Cude 《Journal of the American Water Resources Association》2001,37(1):125-137
ABSTRACT: The Oregon Water Quality Index (OWQI) is a single number that expresses water quality by integrating measurements of eight water quality variables (temperature, dissolved oxygen, biochemical oxygen demand, pH, ammonia+nitrate nitrogen, total phosphorus, total solids, and fecal coliform). Its purpose is to provide a simple and concise method for expressing the ambient water quality of Oregon's streams for general recreational use, including fishing and swimming. The OWQI, originally developed in the 1970s, has been updated based upon improved understanding about water quality behavior. This report describes the historical basis of the OWQI and defines the improved design of the present OWQI. The index allows users to easily interpret data and relate overall water quality variation to variations in specific categories of impairment. This report demonstrates the value of the OWQI in presenting spatial and temporal water quality information. The OWQI improves comprehension of general water quality issues, communicates water quality status, and illustrates the need for and effectiveness of protective practices. 相似文献
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中国省域生态环境质量评价指标体系研究 总被引:103,自引:1,他引:102
提出了省域生态环境质量评价及其指标体系由生态环境质量背景、人类对生态环境的影响程度及人类对生态环境的适宜度需求三部分 组成,并分别提出相应的指标体系及评价方法。通过对中国省区生态环境质量评价分级的实例研究,具体介绍了该方法。 相似文献
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苏北潮滩湿地不同生态带有机质来源辨析与定量估算 总被引:8,自引:2,他引:6
对苏北潮滩湿地表层沉积物以及不同生态带柱状沉积物与植被中的TOC、TN、C/N、δ13C和δ15N的含量进行分析,并通过不同的指标进行相互验证,探讨各测量指标的分布规律,分析不同生态带植被和沉积物间的生物地球化学作用,定量估算不同生态带有机物的来源,对比不同生态带及其植被在苏北潮滩湿地有机质富集中的作用.结果表明:TOC、TN、C/N和δ13C都表现出了比较明显的地带性分布特征;光滩以及光滩和互花米草过渡带内的有机质来源以海源为主,互花米草滩以陆源为主,盐蒿滩也以海源为主,互花米草对生态系统内的有机质有着重要的贡献;研究区互花米草滩、盐蒿滩和芦苇地内,每年新增的TOC、有机质和TN分别达到了6 451t、16 595t和536t;互花米草滩对TOC、有机质和TN的富集量要远大于其它几个带,在整个潮滩湿地生态系统的物质循环和交换中也发挥着不可替代的作用. 相似文献
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The microbiological contamination of waterways by pathogenic microbes has been, and is still, a persistent public safety concern
in the United States and in most countries of the world. As most enteric pathogens are transmitted through the fecal–oral
route, fecal pollution is generally regarded as the major contributor of pathogens to waterways. Fecal pollution of waterways
can originate from wastewater treatment facilities, septic tanks, domestic- and wild-animal feces, and pets. Because enteric
pathogens are derived from human or animal sources, techniques capable of identifying and apportioning fecal sources have
been intensively investigated for use in remediation efforts and to satisfy regulatory concerns. Pollution of human origin
is of the most concern, since human feces is more likely to contain human-specific enteric pathogens. Fecal indicator bacteria
have been used successfully as the primary tool for microbiologically based risk assessment. However measurement of fecal
indicator bacteria does not define what pathogens are present, or define the sources of these bacteria. Microbial source tracking
(MST) methods that have the ability to differentiate among sources of fecal pollution are currently under development. These
methods will ultimately be useful for risk assessment purposes and to aid regulatory agencies in developing strategies to
remediate microbiologically impaired waterways. 相似文献
128.
Indicators are used to draw conclusions about ecological endpoints when these endpoints cannot be measured directly. In many cases, inferences about an endpoint are only possible because assumptions have been made about the relationship between indicator and endpoint; we refer to such indicators as judgement indicators. The validity of inferences made using a judgement indicator can be gauged by examining the known or assumed form of the general relationship between indicator and endpoint. The rules for this kind of inference are a consequence of scale invariance, which originates from measurement theory. For simple indicators comprised of a single indicator measurement, the inferences allowed – equivalence, rank, equality of intervals, and equality of ratios – depend on whether the data are nominal, ordinal, interval, or ratio scaled. For composite indicators containing two or more simple indicators, inferences are also affected by the mathematical form of combination; e.g., whether the terms are summed or multiplied. Standardizing simple or composite indicators can allow inferences about the relative importance of observations, based on the natural range of occurrence. Scale invariance is a particularly important consideration in landscape assessments, since these often make use of judgement indicators. 相似文献
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