F. Paul Bertetti is a principal scientist in geochemistry at the Geosciences and Engineering Division, Southwest Research Institute® in San Antonio, Texas. Mr. Bertetti conducts field and experimental investigations to evaluate and understand the relationships between the aqueous geochemistry and hydrology of the subsurface. He has used hydrochemical data and modeling in numerous studies to characterize flow, recharge, and interconnectivity of several major aquifers, including the Edwards, Edwards-Trinity, and Carrizo-Wilcox aquifers in south Texas. Mr. Bertetti also conducts field, laboratory, and modeling studies to examine the sorption and ion-exchange behavior of dissolved radionuclides and other inorganic constituents.