New biotechnology cleans up radioactive materials

by Atsuko Hirai, Staff Writer

On February 23, it was revealed that a joint research group involving Hiroshima Kokusai Gakuin University and a private company in Japan, has developed a new technology for recovering radioactive materials such as uranium, which contaminate soil and rivers, through the use of microorganisms. The group aims for a practical application of this technology by 2009, eyeing the possibility of utilizing it to clean up radioactive contamination caused by depleted uranium.

According to Ken Sasaki, the leader of the research group and a professor of bioenvironmental chemistry at Hiroshima Kokusai Gakuin University, they have succeeded in recovering three radioactive materials: uranium, strontium, and cobalt. The mechanism behind this process involves a negative electric charge carried by special photosynthetic bacteria. This bacteria, confined in a Y-shaped ceramic of 5 centimeters in length, draws out the radioactive materials, which carry positive ions.

In an experiment lasting six days, in which ceramics containing bacteria were placed in one liter of water that held 20 milligrams of radioactive material, 2 milligrams of radioactive material were recovered per ceramic. Based on experiments of this kind, it is estimated that one ceramic could potentially recover 10-20 milligrams of radioactive material over a period of 3-6 months when it is buried in contaminated soil.

Radioactive materials can be removed with chemicals, but this practice is expensive and has a negative effect on the environment. Particularly in cases of widespread, low-level contamination, the alternative of biotechnology is relatively economical and environmentally-friendly.

This research project was initiated eight years ago. A group of six, including graduate students, has been involved in the work and they applied for a patent at the end of January. Professor Sasaki commented, “This technology can be used to clean up contamination from depleted uranium or radioactive materials that leak out due to earthquakes or other disasters. We hope to introduce this technology to the world from Hiroshima.”