1. Respectively, Geographic Scientist, NSI Technology Services Corporation, U.S. EPA Environmental Research Laboratory, 200 S.W. 35th Street, Corvallis, OR 97333; Aquatic Chemist, NSI Technology Services Corporation, current address: E&S Environmental Chemistry, Inc., P.O. Box 609, Corvallis, OR 97339; Statistician, NSI Technology Services Corporation, U.S. EPA Environmental Research Laboratory, 200 S.W. 35th Street, Corvallis, OR 97333.