Edward R. Landa is a research hydrologist with the U.S. Geological Survey in Reston, Virginia. He received his B.S. in geology from the City College of New York and his M.S. and Ph.D. in soil science from the University of Minnesota. His research focuses on the behavior of metals and radionuclides in soils and aquatic environments. Address: U.S. Geological Survey, 430 National Center, Reston, VA  20192. Internet: erlanda@usgs.gov