Oil accumulating on the coast of Louisiana during the Deep Horizon oil spill in the Gulf of Mexico.
No one disputes that an oil spill at sea is one of the nastier types of industrial accidents. Certainly, no oil company wants this to happen and works hard to prevent it as damage to the environment, negative public reaction, increased government scrutiny, and a big hit to company finances are all probable outcomes for such an event. The spreading oil sheen at the ocean’s surface is a visible marker of the harm being done to marine wildlife, fisheries, and the fouling of nearby beaches, coastal marshes, and other ecologically sensitive areas. Deeper in the water column more harm is done that is less well understood than what is more easily observed at the surface. During the Deepwater Horizon oil spill in the Gulf of Mexico scientists discovered underwater oil plumes, some nearly 10 miles long, which depleted oxygen and harmed ocean life. Moreover, oil accumulated on the sea floor and damaged coral and other ocean-floor dwelling organisms.
The University of Delaware Sea Grant Program lists four general approaches to oil spill clean ups. This is a general overview and is dependent on lots of variable conditions that include the weather, location, and oil type. The abbreviated list is as follows:
- Do nothing. Oil left alone will decompose by natural means. The natural forces of wind, sun, current, and wave action will rapidly disperse and evaporate most oils.
- A more mechanical approach. This involves containing the oil spill with booms and then collecting it with water surface skimmers. Most booms rise up a meter above the ocean surface and can have skirts that float a meter below. Skimmers then float across the top of the oil slick and suck or scoop the oil for storage on nearby vessels or shore installations.
- Chemical dispersants that break up the oil and speed its natural decomposition. Dispersants prevent oil and water from mixing and hence encourages the oil to form small droplets. This increases the oil surface area and leaves it more susceptible to the natural processes noted in point 1. The downside to this approach is that some of the chemicals used are thought to be toxic and the dispersed oil can sink in the water column, which basically hides the problem.
- The use of bacterial and other microorganisms to hasten biodegradation of the oil into harmless fatty acids and carbon dioxide. The natural processes of biodegradation can be speeded up with fertilizing nutrients, like nitrogen and phosphorous, that stimulates microorganism growth.
Chemical dispersants spread by airplane over the Gulf of Mexico during the Deepwater Horizon oil spill.
A novel approach to cleaning oil spills comes from the work of researchers at the University of Southern Mississippi whose work shows that lecithin, an ingredient used in non-stick cooking sprays, and cellulose based polymers derived from plant cell walls can be effective. These ingredients provide the thicker texture to ice cream and smoothies and may offer a better and more natural answer to chemical dispersants. These natural ingredients help disperse oil droplets and keep them near the water’s surface where they can be cleaned by mechanical means. This prevents hiding the problem underwater and allows a definitive and verifiable collection solution at the water’s surface, while also speeding more natural decomposition processes. The oil droplets are coated by these substances, which prevent the oil from sticking to marine life—an end to horrific images of oil covered birds and turtles? And perhaps best of all, since these substances are already part of our food chain, there is little worry about their toxicity. An additional benefit is that they can be produced at large scale and at reasonable cost. Expect to learn more about this rather tasty addition to the cleanup crew’s toolkit in coming years.