PM11 Wildlife Ecotoxicology
Exhibit Hall
8:00 AM - Monday
(PM173A) Biological Half-Life and Oxidative Stress Effects in Mice with Low-Level, Oral Exposure to Tritium.
Kelsey-Wall, A.1, Seaman, J.1, Jagoe, C.1, Dallas, C.2, 1 University of Georgia Savannah River Ecology Laboratory, Aiken, SC, USA2 University of Georgia, Athens, GA, USA
ABSTRACT- Tritium, a radioactive isotope of hydrogen, is a contaminant of concern at former nuclear production facilities, such as the Savannah River Site (SRS). New methods are being employed on SRS to deal with the disposal of tritium, including the irrigation of a hardwood/pine forest with tritiated water from an intercepted contaminant plume in order to reduce concentrations of tritium outcropping into Fourmile Branch, a tributary to the Savannah River. The use of this system has proven to be an effective means of tritium disposal; however, it exposes the terrestrial biota living within the irrigation site to tritiated water. The potential for the spread of tritium contamination from the irrigation site due to animal migration has generated questions about the biological residence, or biological half-life of tritium in rodents. Previous studies have estimated the biological half-life of tritium in mice to be approximately 1.13 days; however, these laboratory studies were not conducted under environmentally realistic conditions. In this study, a laboratory experiment was designed to be more representative of environmental exposure for the determination of the biological-half life by orally administering tritiated water at an approximate concentration of 8,000 pCi/mL to mice over a period of two weeks. In addition, the possibility of oxidative stress induction from exposure to low-level 
-radiation was examined by comparing the activities of oxidative-stress induced enzymes, catalase, glutathione peroxidase, and superoxide dismutase, from exposed mice to control mice. From this experiment, the biological half-life of tritium was determined to be 2.26 ± 0.04 days, almost double the previous estimates. There were also no indications of oxidative stress induction, based on enzyme activities, with exposure to low-level 
-radiation.
Key words: tritium, Mus musculus, oxidative stress , biological half-life