据美国环保署消息，近日美国环保署发表报告称，全美约21%的河流与小溪水质优良，23%的水质一般，55%的河流和小溪水质不佳。
这份报告名为《2008-2009全国河流和小溪评估》。报告显示，美国西部地区水体水质较好，约有42%的河流和小溪水质优良，而在东部高地、平原和低地地区，水质较好的河流和小溪的比例分别为17%和16%。
部分原文报道如下：
Biological condition is the most comprehensive indicator of water body health: when the biology of a stream is healthy, the chemical and physical components of the stream are also typically in good condition. Twenty-one percent of the nation's river and stream length is in good biological condition, 23% is in fair condition, and 55% is in poor condition, based on a robust, commonly used index that combines different measures of the condition of aquatic benthic macroinvertebrates （aquatic insects and other creatures such as crayfish）。 Of the three major climatic regions （Eastern Highlands, Plains and Lowlands, and West） discussed in this report, the West is in the best biological condition, with 42% of river and stream length in good condition. In the Eastern Highlands, 17% of river and stream length is in good condition; in the Plains and Lowlands, 16% is rated in good condition （Figure 1）。
原文链接：<http://water.epa.gov/type/rsl/monitoring/riverssurvey/>
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