食品伙伴網(wǎng)訊 據(jù)美國環(huán)保署消息，近日美國環(huán)保署發(fā)表報告稱，全美約21%的河流與小溪水質(zhì)優(yōu)良，23%的水質(zhì)一般，55%的河流和小溪水質(zhì)不佳。

    這份報告名為《2008-2009全國河流和小溪評估》。報告顯示，美國西部地區(qū)水體水質(zhì)較好，約有42%的河流和小溪水質(zhì)優(yōu)良，而在東部高地、平原和低地地區(qū)，水質(zhì)較好的河流和小溪的比例分別為17%和16%。

    部分原文報道如下：

    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）。

    原文鏈接：<http://water.epa.gov/type/rsl/monitoring/riverssurvey/>