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历时十年的研究表明,美国河流湖泊的水质已得到改进。据该国州与州际污染控制管理人员协会1984年4月初的报导,虽然有毒物质和非点污染对那些企图改进其水质的各个州继续造成威胁,但美国总长度为290万公里的河流中,有58%不存在严重的水质问题。该协会报道,美国有39个州总长为22530公里的河道,16个州总面积为25820公顷的湖面,8个州总面积为2330平方公
A decade-long study shows that water quality in rivers and lakes in the United States has been improved. According to a report by the State and Interstate Pollution Control Administrators Association in early April 1984, while toxic and non-polluting pollutants continue to pose a threat to all states seeking to improve their water quality, the U.S. total length of 2.9 million kilometers of rivers , 58% do not have serious water quality problems. The Association reported that the United States has 39 states with 22,530 kilometers of river courses, 16 states with a total area of 25,820 hectares of lakes, 8 states with a total area of 2330 square kilometers