College of Arts & Sciences 

My research interests lie in the application of radioisotopes to the study of the Earth and the environment. My recent research has focused on the long-lived halogen radioisotopes ¹²⁹I and ³⁶Cl. Both of these isotopes are produced naturally in the atmosphere and in the Earth's crust. During the past fifty years, these isotopes have also been produced in large quantities as a consequence of nuclear activities, such as nuclear weapons testing and the operation of nuclear fuel reprocessing plants. The anthropogenic signal often overwhelms the natural signal of these isotopes in surface reservoirs which actively exchange with the atmosphere.

There are many potential applications of these isotopes. For example, many iodine isotopes are short-lived and hazardous; however, they often decay quickly so that past releases in an area cannot be estimated. Since ¹²⁹I is released concurrently with other iodine isotopes, but is much more persistent in the environment due to its long half-life, measurements of this isotope can provide a proxy for short-lived iodine isotopes which may have decayed away since the time of release. Additionally, the strong, easily detectable signal of anthropogenic ¹²⁹I and the association of iodine with organic matter provide a means of "tagging" organic matter as it moves through the Earth's surface. For example, we are studying the transport of ¹²⁹I from a nuclear fuel reprocessing facility into the bottom sediments of the Great Lakes, to determine how soil organic matter moves through a watershed into a lake. Another application of ³⁶Cl and ¹²⁹I lies in the use of the natural production of these isotopes in the crust to date old groundwater and hydrothermal fluids. We are analyzing ³⁶Cl and chloride concentrations in water samples from Saratoga Springs, NY to determine the age, mixing and transport history of these fluids, and sources of salinity in the water. Other current projects in our laboratory center on improving analytical techniques to derive iodine and chlorine from natural samples.