Wed 27th April @ 12 pm, Rm 312.222

Thermal waters at Yellowstone National Park contain high concentrations of arsenic (up to 15 mg/L), lithium (up to 8 mg/L), boron (up to 28 mg/L), fluoride(up to 48 mg/L), and silica (up to 800 mg/L). Their geochemical source, redox transformations, and transport have been challenging to decipher. Arsenic speciation requires knowledge of thioarsenites and thioarsenates. We have measured the mass flux of these elements into 2 major rivers and found that there is little to no attenuation for 20‐30 miles downstream. These results have implications for arsenic poisoning in other countries.

A short bio.:

Currently a senior scientist of 40 years experience with the U.S. Geological Survey, Dr. D. Kirk Nordstrom is recognized internationally for his research on acid mine drainage, radioactive waste disposal, thermodynamic data evaluation, geothermal chemistry, arsenic geochemistry, and geochemical modeling. He has more than 250 publications in hydrogeochemistry that include analytical chemistry, field studies on surface and ground water, experimental geochemistry, geomicrobiology, thermodynamics, and the development and evaluation of speciation models. He is particularly known for his research on the measurement of negative pH in mine waters, his evaluation and compilation of thermodynamic properties for aqueous speciation calculations, and evaluating natural background concentrations at mine sites.