BIOREMEDIATION OF ALASKAN SITES UNDER WAY
Exxon Corp. has begun bioremediation of designated sites soiled by the Exxon Valdez oil spill on the shoreline of Prince William Sound and Gulf of Alaska.
Bob Mastracchio, Exxon technical manager in Anchorage, said a team moved ashore at Herring Bay on Knight Island to apply liquid and granular fertilizers to a lightly oiled beach.
In bioremediation, fertilizers containing nitrogen and phosphorous are added to increase the number of native oil degrading microbes. Oil is then converted to carbon dioxide, water, and more microbes.
Exxon said laboratory tests and field sightings show that nutrients and oxygen can penetrate deeply enough into sites struck by the oil spill to permit the microbes to biodegrade subsurface oil.
Bioremediation is the least intrusive cleanup technique available for subsurface oil, Mastracchio said.
Knight Island is one of about 400 sites in the area scheduled for bioremediation under a plan developed by Exxon and federal and state agencies. It was approved by Coast Guard Adm. D.E. Ciancaglini, the federal on scene coordinator.
BIOREMEDIATION DATA
Exxon also began a program, at Ciancaglini's request, to gather more data on bioremediation by applying fertilizer to a site at Bay of Isles on Knight Island.
That and other locations, Mastracchio said, will be monitored jointly for 6 weeks by the Coast Guard, Environmental Protection Agency, National Oceanic and Atmospheric Administration, Alaska Department of Environmental Conservation, and Exxon.
Results will test the success and safety of bioremediation and serve as a basis for determining the timing and need to reapply fertilizer. These results will be available to the public.
To keep birds and wildlife off newly fertilized beaches for the first 24 hr, workers will deploy brightly colored helium balloons in the intertidal zones. Roped flagging also will extend across the rear of treated areas.
"Fertilizers applied in recommended amounts are a low risk to wildlife for a brief period," Mastracchio said. "Within hours of application, dilution by tidal flushing reduces any effect."
Liquid and granular nutrients were applied to more than 70 miles of shoreline last year, he said, with no harmful effects observed. Both fertilizers stimulated the growth of oil degrading microbes on and beneath the surface of treated beaches, resulting in a faster breakdown of oil.
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