Environmental Risk and Benefits of Oil Dispersing Chemicals - BP Spill Dispersant Agents Use

The environmental risk of oil dispersing chemicals is another risk of the massive BP Horizon oil spill that is still spewing between 5,000 and 120,000 barrels a day into the Gulf of Mexico. We are looking at a disaster worse than the Exxon Valdez disaster now. The Environmental Protection Agency (EPA) has just ordered British Petroleum (BP) to switch the oil dispersant being used in the oil spill clean up. It seems we should add political grandstanding adds a further risk to the environmental cleanup.

The EPA has ordered BP to identify a less-toxic and potentially more effective option in 24 hours. It than must start using the alternative within three days. What is striking is the two formulations of the Corexit brand are on the EPA's list of approved dispersants. Politicians look to label and disperse blame and perhaps influence commercial contracts are pushing for other brands to be used.

The oil spill has now washed ashore in some areas, forming a filthy sheath in parts of the vulnerable marshland. Wildlife rescue crews are doing their best, oyster reefs are threatened and fishing in the gulf is banned. One thing that I haven’t seen much about is the toxic make up of the oil dispersing chemicals being used in the clean up until recently. The use of the oil dispersants is a trade-off between the spill landing ashore and potential harm to offshore wildlife.

In what appears to be a response to political pronouncements and grandstanding in the House this week the EPA has ordered the switch of oil dispersing chemicals by BP. One has to ask why, with the untold spills in the past and the intensity of this one why is this an issue now. I have to put credence in the rumors that it is a push for either alternative blame or for commercial contracts to either constituent’s benefits or lobbyists. 

The EPA announced in a statement that “BP is using this dispersant in unprecedented volumes and, last week, began using it underwater at the source of the leak — a procedure that has never been tried before.” 

“Because of its use in unprecedented volumes and because much is unknown about the underwater use of dispersants, EPA wants to ensure BP is using the least toxic product authorized for use.” 

The EPA added, “toxicity data does not indicate any significant effects on aquatic life” and there “is a good indication that, so far, the dispersant is effective.” 

BP has responded by saying that Corexit ”was readily available in the quantities required by the spill response plan, which was pre-approved by the government for use in spill response.” 

The Sugar Land-based Energy Services Division of Nalco Co makes Corexit. In the month since the April 20 explosion an estimated 655,000 gallons of Corexit oil dispersant has been sprayed on the sea or at the leak. It is estimated 55,000 gallons of Corexit have been used underwater. 

Nalco in a statement replied “We are gratified that the EPA has acknowledged that the use of Nalco's dispersants has been effective and has had no undue impact on the marine environment,” 

A few weeks’ ago Mani Ramesh, Nalco's chief technology officer said Corexit's active ingredient is an emulsifier also found in ice cream; he disputed environmental groups' claims that it is harmful to marine life. At this time the EPA initially authorized BP to spray the dispersant over the oil slicks. Only last weekend the EPA allowed BP to inject the dispersant directly at the site of the oil leak underwater, 

The purpose of an Oil Spill Dispersant is to speed up the biological breakdown and weathering of crude oil that has flowed into the ocean. Secondly the aim is to reduce the impact of oil on the sensitive foreshore environments if it comes ashore. 

Dispersants have an active ingredient called surfactants. Surfactants are chemicals that have both hydrophilic (like water) and oleophilic (like oil) components in the chemical compound. These chemicals help the creation of small oil droplets to facilitate faster natural biological breakdown (biodegradation) and dispersion.

Oil Spill Dispersants are composed of three main component groups.

1. Surface-active agents (surfactants),
2. Solvents (hydrocarbon and water based),
3. Stabilizing agents.

Nalco’s Ramesh said. “Dispersants work on an oil spill as dishwashing detergent works on a greasy skillet: they break up oil into tiny droplets that sink below the water's surface where naturally occurring bacteria consume them. Without dispersants, oil stays on the water's surface, where bacteria can't get at them.”

Undispersed oil is particularly damaging to birds as the oil sticks to them, which can render them flightless. Dispersed oil limits adhering to the bird’s feathers and the absorption onto surfaces. Oil slicks as we see now in the Gulf spill threaten to foreshores, marshlands and intertidal communities. 

Time is the essence for using oil dispersants due to the changing properties of oil as it weathers in the water and the oil slick’s movement onto the foreshores or estuarine environments such as fragile marshlands. It may well be this window is only a few hours in difficult weather scenarios to two days in calm conditions.

Hence a management plan needs to in hand, and as we see in the BP Horizon incident political influence may hinder that urgent need, this window of opportunity may be as little as only a few hours. Sometimes if the conditions are favorable, a day or two may be the window of opportunity. The Oil Spill Dispersants are delivered via fixed wing aerial dispersant. 

The choice with oil dispersants is really do you risk making the oil more toxic for at sea animals such as sea turtles, fish, shrimp or mammals such as whales and dolphins. The Gulf is also home to delicate blue fin tuna spawning grounds. 

The alternative is risk-undispersed oil coming ashore and saturating the delicate foreshore. Mark Floegel of Greenpeace said it more bluntly, 'Do you kill the fish or do you kill the birds?

Closer to shore we have oyster reefs and sea grass beds. These also provide food and shelter for birds, dolphins, crayfish, fish, lobster, conch, scallops and shrimp. Allison Nyholm, a policy adviser at the American Petroleum Institute pointed out 'Birds aren't naturally made to have dispersant sprayed on them. You don't want to interject a chemical reaction where you don't have to.' On the foreshore we have bird, sea turtle and loggerhead turtle nests. 

The environmental risk of oil dispersing chemicals has to be weighed up with not doing anything. The choice as in the current case is what is available. Different dispersants have different properties and toxins. Some are described as not as toxic as others, the argument is these may be not as effective. Another sad side affect of oil spills that seems unavoidable at his point.

There has been successful use of Oil Spill Dispersants around the world. Before the BP Gulf spill a good example is the Sea Empress oil spill.

The February 1996 off Milford Haven in the U.K. the Sea Empress was grounded. The oil spill involved 72,000 tonnes of Forties Blend crude oil with 370 tonnes of Heavy Fuel Oil. 

Aircraft onto the oil slicks sprayed an estimated 445 tonnes of chemical dispersants.  They estimate at stopped at least 36,000 tonnes of oil from the Sea Empress coming ashore in a very sensitive foreshore region of Wales. This equated to approximately 57,000-110,000 tonnes of oil and emulsion. 

According to British scientists the oil that actually came ashore was between 10,000-15,000 tonnes. Without dispersant it is estimated 5 to 10 times this amount of oil and emulsion would have hit the delicate foreshores. In a situation similar to what we are seeing today in Louisiana, Milford Haven’s coastline has the only coastal National Park in the UK. The nearby islands are bird sanctuaries for gannets, guillemots, puffins and Manx shearwaters.