Scientists eye algae for nuclear cleanup

EVANSTON, Ill., April 4 (UPI) -- U.S. researchers say common freshwater algae can remove radioactive strontium from water and could be used to clean up nuclear waste.

Scientists at Northwestern University and Argonne National Laboratory say Strontium 90 is one of the more dangerous radioactive fission materials created within a nuclear reactor and is present in the 80 million gallons of radioactive waste sludge stored in the United States, a Northwestern release reported Monday.

Strontium 90 has a half-life of about 30 years and is chemically very similar to calcium and thus is drawn to bone, creating a high cancer risk from exposure when strontium is bound in bones for many years.

The researchers say Closterium moniliferum, one of the bright green algae often seen in ponds, can sequester strontium in the form of barium-strontium-sulfate crystals.

The knowledge could lead to using algae for direct bioremediation of waste or accidental spills in the environment, they say.

"Nuclear waste cleanup is a problem we have to solve," senior researcher Derk Joester, who experienced Chernobyl's radioactive fallout when he was a teenager living in southern Germany, said.

"Even if all the nuclear reactors were to shut down tomorrow, the existing volume of waste is great, and it is costly to store.

"We need to isolate highly radioactive 'high-level' waste from 'low-level' waste," he said. "The algae offer a mechanism for doing this, which we would like to understand and optimize."