This is not the case with another isotope, iodine-129, released concurrently with iodine-131. It is not as radioactive, which makes it much harder to measure, but it is much longer lasting and, as it concentrates in certain areas over time, it may become more hazardous. "Due to its long half-life and continued release from ongoing nuclear energy production, [iodine-129] is perpetually accumulating in the environment and poses a growing radiological risk," the authors point out.
The production rate of these two isotopes in a nuclear reactor occurs at a fixed ratio of 3 parts iodine-131 to one part iodine-129. The two substances travel together, so the presence of the easily detectable isotope also signals the presence of the longer-lived one. "If you have a recent event like Fukushima, you are going to have both present. The iodine-131 is going to decay away pretty quickly over the course of weeks, but the iodine-129 is there forever, essentially," Landis says. However, he explains, "Once the iodine-131 decays, you lose your ability to track the migration of either isotope."
Thus, the group's research turned toward the development of an innovative alternative approach to measuring and tracking the iodine. What became an important off-shoot of their work was the methodology of using the benign radioisotope, beryllium-7, as the tracking indicator. It's an easily detected natural radionuclide, and is routinely used by the Dartmouth researchers in their environmental analyses.
The Dartmouth researchers have shown that beryllium-7 follows the same transpor
|Contact: Joseph Blumberg|