By Russell Chianelli
When the BP oil well, located 50 miles off the coast of the U.S. in the Gulf of Mexico and one mile below the ocean surface, blew out, I couldn’t help but think back to the March 1989 Exxon Valdez oil spill.
At the time, I was working as an Exxon’s Corporate Research Laboratory and was designated as the lead scientist for the bioremediation project to clean the beaches in Alaska .
People remember the Exxon Valdez spill, but they don’t realize that it wasn’t the biggest tanker spill; this was the Amoco Cadiz accident in 1978 off the coast of France in Brittany . The Amoco Cadiz was about five times larger (approximately 220,000 tons vs. approximately 40,000 tons). However the largest oil spill in the world before the Gulf War was the 1979 Ixtoc Blow-Out in the Bahia de Campeche, Mexico. When PEMEX drilled a deep exploratory well, similar to the BP blowout, the sea bottom gave way and in nine months approximately 400,000 tons of oil was released. That’s more than 10 times the amount released by the Exxon Valdez. The Ixtoc Blow-Out lasted for 9 months until a relief well was drilled. Estimates ranged from 4000 barrels to 30,000 barrels per day being released, illustrating the difficulty in knowing exactly the amount being released from drilling blow-outs.
The Ixtoc Blow-Out was very similar to what we’re experiencing with the BP spill. Yet, in the Ixtoc Blow-Out very little of this huge amount of oil ever reached the shores of Padre Island, Texas, approximately 600 miles away. Why? Because of hydrocarbon-eating microbes called hydrocarbon degraders.
Hydrocarbon degraders are microorganisms that can consume oil, creating CO2, H2O and more of themselves. Approximately 50 percent of the petroleum goes to make more hydrocarbon degraders. The hydrocarbon degraders are then consumed by higher organisms (plankton) which provides food for marine life such as fish.
Every year 2 million to 12 million tons of oil naturally seep from the ocean floor and into the sea. In fact, many of the deposits in the Gulf of Mexico were discovered by observing these oil seeps, which is why the hydrocarbon degraders are everywhere, waiting for their “dinner” or fuel. They in turn provide “dinner” for plankton and then fish. Fishermen should be prepared for the extra catches that are coming because after every major oil spill there’s an explosion of local fish.
But before a fish explosion can happen, the microorganisms need to be able to get to the oil and digest it. Since oil and water don’t mix, adding a dispersant will accelerate the breakdown of the oil by making it more available to the microorganisms.
The best option for oil in open water is to use an EPA approved dispersant, such as COREXIT. BP has begun using dispersants. It is important to remember that the dispersants remove a surface oil slick by dispersing it in the water and this accelerates the ability of the hydrocarbon degraders to consume the oil. Removal of the surface slick also protects the beaches. In the case of the Exxon Valdez a storm came before dispersant were used and the storm covered the beaches with oil. A look at the beaches in Prince William Sound after the storm (www.materials forenergy.org) show a thick coating of fresh oil everywhere. This is not the case in the current spill because of the use of dispersants.
What would make this clean-up even more effective would be to use nutrient enhanced bioremediation. The hydrocarbon degraders like any living organism need nitrogen and phosphorous (nutrients) to make more of themselves. In the open sea the rate at which they consume the oil is limited by the availability of the nutrients. Nutrient enhanced bioremediation, the project I worked on in Valdez is the addition of nutrients to accelerate the natural rate of biodegradation. It is just like adding fertilizer to your garden plants.
The science of hydrocarbon degraders on oil spills was originally investigated by Dr. Ronald Atlas, now of the University of Louisville, who studied the Amoco Cadiz oil spill, which occurred on March 16, 1978 . The Amoco Cadiz was the largest tanker spill ever, 220,000 tons of crude oil on the beaches of Brittany, France. Nutrients (nitrogen and phosphorous) from farms above the beach enhanced the growth of the hydrocarbon degraders giving rise to the concept of nutrient enhanced bioremediation for dealing with oiled beaches.
It was this idea that Ron Atlas and myself developed for the beaches in Alaska after the Exxon Valdez oil spill. This was the largest successful bioremediation project ever attempted. The materials used were INIPOL EAP-22, an oleophilic (sticking to oil) nutrient and CUSTOMBLEND, a typical agricultural fertilizer. These nutrients were successfully used on the beaches in Alaska and not on oil in the open water. The oil on the beaches was consumed in approximately two weeks. This was in the cold waters of Prince William Sound. In the warm waters of the Gulf of Mexico this process should be even faster.
Bioremediation: Helping Nature’s Microbial Scavengers, R.R.Chianelli, Proceedings of the Royal Institution, vol.65, 105-126(1994). Download Bioremediation Technology Development and Application to the Alaskan SpillMicrobial Degradation of Petroleum Hydrocarbons: an Environmental Perspective, Ronald M. Atlas, Microbiological Reviews, Vol.45, No.1,180-209(1981).