NORA Manufacturing Sector Strategic Goals
R039800 - 021H: Evaluation of Tritum: Relative Biological Effectiveness and Cancer Mortality (9800)Start Date: 9/1/2010
End Date: 8/31/2012
Principal Investigator (PI)Name: Joan Karr
Sub-Unit: Office of Extramural Projects
Funded By: NIOSH
Primary Goal Addressed6.0
Secondary Goal AddressedNone
Attributed to Manufacturing100%
They will utilize Bayesian methods to estimate the Relative Biological Effectiveness (RBE) of tritium with reference to gamma radiation. The RBE has been reevaluated by a number of radiation experts, and is the subject of a recent systematic review. They will utilize the information compiled over the years at Savannah River Site (SRS) to directly address the relationship between cancer mortality and tritium exposure. They will consider cancer mortality and tritium exposure in conjunction with other radiation dose measures recorded among SRS employees. This work will address a form of radiation that has received little attention, despite its relevance to human populations. In addition, this work will assist the NIOSH in decision-making concerning compensation for cancer outcomes among nuclear facility workers.
"X-rays and gamma radiation are well-established carcinogens with substantial evidence of carcinogenicity in humans from epidemiological research. In contrast, there is very little epidemiological research on the human health effects of beta radiation. Even less is understood about the effects of chronic exposure to beta-emitters, such as tritium, a low-energy radioisotope of hydrogen that is produced through nuclear fuel production. Radiation protection standards assign a relative biological effectiveness (RBE) of 1 for beta-emitters compared to gamma-emitters. However, a recent scientific review concluded that the RBE of tritium needs reevaluation. The goal of this proposed study is twofold. First, we propose to estimate the RBE of tritium based on data from the existing literature. The ultimate goal is to apply an accurate RBE for tritium to examine the relationship between chronic, low-dose tritium exposure and cancer among a cohort of nuclear production workers at the Savannah River Site (SRS), the nation’s only large-scale tritium production facility. Second, we propose to utilize the information regarding the RBE of tritium to reevaluate the cancer mortality associated with other forms of radiation exposure in conjunction with tritium at the SRS facility.
There is very little epidemiological evidence concerning the effects of protracted exposures to tritium and its relative biological effectiveness compared to gammaemitters. The USDOE Savannah River Site is unique in that it was involved in tritium production for nuclear weapons. The goal of this project is to evaluate the association between cancer and estimated tritium dose in this cohort. In addition, they will use Markov Chain Monte Carlo methods to combine current information on the RBE for tritium with our epidemiological data in order to estimate a (posterior) distribution of the RBE for tritium.