'Farming' strategy may help clean up spill Gulf's best bet is fertilizer mix and oil-eating bacteria, Md. expert says. PERSIAN GULF SHOWDOWN

February 21, 1991|By Jon Morgan | Jon Morgan,Evening Sun Staff

The best weapon in the battle against the massive Persian Gulf spill is probably a blend of fertilizers that find oil nutritious, according to a panel of international experts led by a Maryland scientist.

Rita R. Colwell, chairwoman of the Maryland Biotechnology Institute, headed a panel assembled at the request of U.S. officials assisting Saudi Arabia in dealing with what may be the largest oil spill in history.

Colwell, who says she is willing to travel to Saudi Arabia to participate in the cleanup, is also chairwoman of the American Academy of Microbiology and one of the world's leading authorities on fighting spills by natural means, chiefly through the use of bacteria that consume oil.

Her panel recently recommended the use of nutrients to help encourage the growth of naturally occurring bacteria, yeast and fungi in the gulf. This is a process known as bio-remediation.

"We recommended that they add the same kind of fertilizer that farmers use on their fields," Colwell said. A liquid mix could be sprayed on the beaches by workers, she said.

Depending on the course of the war, which governs the ability of workers to skim the water's surface and scrub the Saudi beaches, 60 to 80 percent of the oil could be cleared in two years, Colwell said. With the right weather and other conditions, most traces of the spill could be gone in three to five years, she said.

"It won't be immediate. There hasn't been much effort to mechanically clean it because it is a war zone," Colwell said.

The oil slick was discovered last month floating off the shore of Kuwait and U.S. officials accused Iraq of releasing the crude to thwart an allied invasion. Iraq blamed the U.S. for bombing oil facilities. Some estimates put the slick at nearly 500 million gallons, though recent reports indicate that may have been overstated.

Scientists have for years experimented with laboratory-grown bacteria to clean oil spills, but the results have been mixed, said Colwell, who has also assisted in the clean up of the spill from the Exxon Valdez off Alaska.

Bacteria that is grown in a laboratory and introduced into an environment tends not to survive as well as its native cousin, she said. The most effective systems encourage bacterial growth, she said.

"The process tends to be a natural one. It's like a balanced diet for humans," Colwell said.

She recommends a blend of oleic acid, nitrite and phosphate to feed single-cell microbes such as pseudomonas and vibrio. Common in sea water, these bacteria release enzymes which break down oil so the bacteria can absorb some of the resulting compounds.

The microbes themselves are eaten by microscopic animals, which are eaten by fish, all of which would be harmless to the desalination plants that provide Saudi Arabia with drinking water, Colwell said. This may not be the case if large amounts of laboratory-grown bacteria were released, she said.

The bacteria method would probably work best along beaches and in shallow inlets of the Persian Gulf. Open-water dispersal of nutrients holds less promise because they often sink or are hampered by wave action, Colwell's panel said.

"The benefits of oil bio-remediation at sea are at this time indeterminate, and it is likely that natural events will be as effective in removing oil from the sea surface as attempts to accelerate this biological process," according to a statement by the panel.

Colwell said she expects to get a response from officials in Saudi Arabia in a few weeks. If asked, she said she would go there to help with the cleanup.

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