The 1972 Clean Water Act led to significant improvements in water quality nationwide, according to a new study co-authored by Berkeley and Iowa State University researchers. The most comprehensive study of its kind to date, it analyzed 50 million water quality measurements from 240,000 monitoring sites between 1962 and 2001, determining that most of 25 water pollution measures had improved, and 12 percent more rivers were safe for fishing after the bill's enactment. For more on this, see our press release at Berkeley News.