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Peggy O'Day

Peggy O'Day
Professional Title: 
Professor, Life and Environmental Sciences
(209) 228-4338
Sustainability Research and Engineering, Room 457
Lab Location: 
Sustainability Research and Engineering, Room 458
Ph.D., 1992 — Stanford University
M.S., 1984 — Cornell University
B.S., 1981 — University of California, Davis
Research Interests: 

Peggy O'Day is environmental geochemist who studies the chemistry, reaction, and transport of inorganic contaminants and species, primarily metal and metalloid elements, in surface and subsurface systems.  She specializes in the use of spectroscopic and microscopic methods, especially synchrotron X-ray techniques, to determine element speciation and molecular-scale mechanisms of biogeochemical reactions in natural systems and laboratory analogs.  She develops and applies thermodynamic, kinetic and reactive transport models for synthesis and quantitative description of biogeochemical cycling, reactivity, transport, and bioavailability.

Current research projects include:

  • Characterization of element speciation and solid phases in natural and engineered airborne particulates, and their impacts on human health through cellular response.
  • Surface reactivity of mineral phases with respect to metal ion adsorption using molecular computational methods, spectroscopic characterizations, and geochemical modeling.
  • Environmental influences on mercury speciation and methylation.
  • Novel methods for remediation of soils and sediments through application of reactive amendments.
  • Mechanisms and rates of abiotic and biotic uranium oxidation linked to nitrogen and iron cycling, and dissolution mechanisms and rates of uranyl oxide, silicate, and phosphate phases.
Interdisciplinary/Multidisciplinary Group: 
Environmental Sciences