Tests show essentially no change in the acidity of Sierra lakes during the past 15 years.

The 1965 study of Sierra lakes was supported in part by the U.S. Public Health Service Research Grant No. UI00484 from the National Center for Urban and Industrial Health; the 1980 part of the study by Southern California Edison Company. The authors thank the following for assistance in sampling Sierra lakes; Mel Wehmueller and Bob Cloud, Southern California Edison helicopter pilots; Don Southward, SCE helicopter maintenance; Tom Keeney, SCE research and development; and John E. Warnecke, Staff Research Associate, Department of Soils and Environmental Science, University of California, Riverside.