Revision History for SIR 2011-5115 Gregory C. Johnson, Tammy M. Zimmerman, Bruce D. Lindsey, and Eliza L. Gross Factors Affecting Groundwater Quality in the Valley and Ridge Aquifers, Eastern United States, 1993Ð2002 ----------------------------------------------------- Posted online August 11, 2011 ----------------------------------------------------- Revised and reposted October 3, 2011 Page 55 - First column, second paragraph: The term "nitrate-nitrogen concentrations" has been changed to "nitrate concentrations." Page 57 - First column, second paragraph: The term "nitrate-nitrogen concentrations" has been changed to "nitrate concentrations."