The WIPP Underground may be ideal to study effects of Very Low Dose Rates on Biological Systems
Low Background Radiation Experiment
We’re all bathing in it. It’s in the food we eat, the water we drink, the soil we tread and even the air we breathe. It’s background radiation, it’s everywhere and we can’t get away from it.
But what would happen if you somehow “pulled the plug” on natural background radiation? Would organisms suffer or thrive if they grew up without their constant exposure to background radiation? That’s what a consortium of scientists conducting an experiment at the Waste Isolation Pilot Plant aim to find out.
Despite being an underground repository for transuranic radioactive waste, WIPP’s underground is close to radiation-free, and such an experiment is taking advantage of this fact.
NMSU Professor Geoffrey Smith removes a sample while conducting the Low Background Radiation Experiment at the Waste Isolation Pilot Plant
Dr. Raymond Guilmette, director of the Center for Countermeasures Against Radiation with the Lovelace Respiratory Research Institute, was one of the scientists who first conceived the idea of a biology experiment at WIPP. Roger Nelson, Chief Scientist of the Department of Energy’s Carlsbad Field Office, was also an early supporter of such a project.
The experiment at WIPP involves using two different types of bacteria, one of which is very sensitive to radiation and the other which is very resistant.
The bacteria strains are being grown in both simple and complex growth media, and future experiments will involve growing the bacteria with and without manganese, which is connected with the second strain’s ability to resist radiation.
This pre-World War II, seven inch thick steel chamber is used to incubate the below-background treated cells in the WIPP underground
One third of the experiment takes place in the WIPP underground, next to the EXO project in the northern end of the repository. The idea is to let the two strains of bacteria grow side-by-side in an environment where they are receiving virtually no background radiation. In fact, the bacteria incubator has been placed in a pre-World War II steel chamber to eliminate even the slightest amount of background radiation. The bacteria underground will receive close to zero radiation dose for hundreds of generations.
NMSU student and Carlsbad Environmental Monitoring and Research Center employee Adrianne Perry, at left, and Smith, conduct analytical work on bacteria samples in a controlled environment chamber
The rest of the experiment takes place inside of a room near the waste handling bay at WIPP’s above-ground facility. There, for comparison, the two strains of bacteria grow at natural background radiation levels, and another part of the experiment exposes both types of bacteria to significantly higher levels of radiation above normal background. Potassium chloride, a naturally occurring radioactive material normally used as a dietary salt substitute, is used to provide these higher levels. Researchers can then compare how well the bacteria does at zero, natural and above-natural levels of background radiation.
Biological effects measured include growth rate, growth yield and protein production. Incubators are used to control temperature, light, humidity and air quality.
The experiment at WIPP aims to better understand the effects of low-dose radiation by providing more insight into the role of background radiation in maintaining the fitness of living organisms.