Have U.S. surface waters responded to the 1990 Clean Air Act amendments?

Jeffrey S. Kahl, John L. Stoddard, Richard Haeuber, Steven G. Paulsen, Rona Birnbaum, Frank A. Deviney, James R. Webb, David R. DeWalle, William Sharpe, Charles T. Driscoll, Alan T. Herlihy, James H. Kellogg, Peter S. Murdoch, Karen Roy, Katherine E. Webster, N. Scott Urquhart