Dr. D. Kirk Nordstrom is currently a senior scientist with more than 30 years with the U.S. Geological Survey, Dr. Nordstrom is recognized internationally for his research on acid mine drainage, radioactive waste disposal, geothermal chemistry, geomicrobiology, arsenic geochemistry, thermodynamics, and geochemical modeling. He has a B.A. degree in chemistry from Southern Illinois University, a M.S. degree in geology from the University of Colorado, and a Ph.D. in applied earth sciences from Stanford University. With more than 220 publications, he is particularly known for his measurement of negative pH in mine waters, his evaluation and compilation of thermodynamic properties, arsenic geochemistry, and natural background concentrations at mine sites.