DOE scientists fight landmines with glow-in-the-dark microbes

NEW ELLENTON, S.C-Here at the Energy Department's Savannah River Site, the mission has historically focused on nuclear weapons. But today, a select team of SRS scientists is tackling a lower-tech military threat-landmines-in a creative way, by harnessing the powers of glow-in-the-dark microbes.

Under a method designed by SRS microbial ecologist Carl B. Fliermans, specialists would travel to known minefields and scatter, by air or by truck, a specially grown microbe that glows only in the presence of chemicals known to be emitted by landmines. Using night-vision goggles, or even the naked eye, experts would then be able to detect clusters of the glowing bacteria. Once sighted, the mines could be safely eliminated.

The new system, which scientists hope to deploy within 12 to 18 months, works because most landmines contain TNT, a chemical that typically vaporizes in small amounts. Each gram of soil typically contains up to a billion microorganisms, some of which happen thrive on the chemical byproducts of TNT's vaporization. In turn, some of those TNT-eating microbes can be easily made to luminesce when the ingestion of TNT occurs.

Once the right microbes for the job are identified, a process now underway at SRS, officials would be able to carry small amounts of microbes into a mine-laden zone and quickly incubate a supply in a 55-gallon drum.

The method presents several advantages over traditional mine-detection systems, advocates say. The old-standby, detection by electromagnetic fields, has plunged in usefulness, now that mine manufacturers have become proficient in building their weapons with very little metal.

With magnetism ruled out, mine-clearers are left with only two feasible alternatives, Fliermans said. One is to have humans poke the ground diagonally with a stick every couple of inches, a tedious, expensive and inefficient task, not to mention an extraordinarily dangerous one. The other is to use dogs to detect the release of small amounts of telltale chemical odors emanating from mines. But this method is not foolproof, either, since dogs can sometimes catch barely noticeable colds that reduce their noses' sensitivity to odors.

In the meantime, experts agree that the problem of landmines, which was already serious, is getting worse. There are an estimated 80 million to 110 million landmines laid in 70 countries worldwide, and they result in 25,000 casualties per year. Moreover, mines are still being laid: One estimate from a few years ago suggested that for every mine taken out, 200 more are laid. "The point is, we're losing the battle," Fliermans said.

The microbe method is not the only solution currently under development. One team led by University of Montana biologist Jerry Bromenshenk is seeking to harness bees as TNT detectors. Another team, led by Neil Bruce at the University of Cambridge in England, is seeking to biodegrade the active ingredients in landmines by using plants that suck up their explosive compounds.

The SRS team honed its method during a November 1998 mission to Mozambique, a country blessed with rich soil but cursed with an estimated one million mines that were laid between 1968 and 1994. The team chose Mozambique because its mines had been in place long enough for useful collections of microbes to become established.

During 10 days in the field, Fliermans and his team took soil samples, packed them in dry ice and liquid nitrogen and air-expressed them back to the U.S. for analysis. The SRS team had to beat the clock; the samples had to be analyzed no more than 50 hours after they were taken or else they would be useless.

Finding the right microbe "was like looking for a needle in a haystack, but it was not serendipity. We knew what we were looking for," Fliermans said. "We had looked in the U.S. at areas that manufactured TNT in the 1940s as preparation, and then went to Mozambique with a more selective approach."

Right now, the SRS team is studying roughly 40 different microbial cultures in an effort to identify which one has the greatest sensitivity to TNT. Fliermans said that the mix of microbes used in the field will eventually depend on what the local climate is, since the microbes will have to blend in with the native soil.

The project has received funding from the Defense Department's night vision directorate at Fort Belvoir, Va., and might one day be utilized by soldiers in peacekeeping missions in mine-laden areas. But the method's designers predict that its most immediate impact will be felt in the humanitarian and commercial sectors. The International Red Cross has expressed interest, as have petroleum and pipeline companies that operate in former battle zones, Fliermans said.

The impact of landmines on Mozambique has grown worse in recent weeks, as massive flooding in some areas has served to uproot mines and send them floating into new areas undetonated.

"The economy of Mozambique has been ruined by mines," Fliermans said. "A land mine can cost three to five dollars to make and $1,500-3,000 to remove. People live on very narrow roads of life. They're relegated to areas they've been on before. Now they can't trust even those paths anymore."

The main scientific obstacle right now, Fliermans said, is making sure that the microbes being used do not get triggered by nitrogenous substances other than TNT, such as animal urine. But the stiffer obstacle, he said, is funding. "We do not have funding for the project after the middle of this year," he said. "We are in the process of searching for additional funding."

If the Energy Department, as expected, takes title for the procedure's patent, he added, they would not be stingy with it. "They would make it available to anyone who wants to use it," he said.