Following the Valdez spill in Alaska in 1989, Exxon scientists worked closely with the U. S. Environmental Protection Agency (EPA) and the State of Alaska, to conduct the most extensive bioremediation study on oiled shoreline ever carried out. Over $10 million was spent conducting this research. The process involved applying fertilizers on intertidal shorelines to stimulate the growth of indigenous oil-degrading microbes and accelerate the rate of natural degradation of the oil. In analyzing the data from this program, Exxon developed unique approaches, focusing on specific changes in the oil chemistry to verify the degradation rate increase provided by the added nutrient. Such a sophisticated approach was required because of the problems inherent with measurement of total petroleum hydrocarbon in the sediment to define the degradation rate. Results show that the rate of oil biodegradation on fertilized beaches was from three to more than five times faster than on unfertilized beaches.
This paper summarizes the bioremediation research conducted, and the extensive information obtained. The experience gained by Exxon, including pioneering work on internal markers, applies directly to bioremediation studies in other environments. Some of this experience is being extended to the remediation of inland contaminated sites and there is a major effort now underway to identify low-cost bioremediation techniques for in-situ restoration of such sites.