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Dispersants Long-Term Effects

When BP injected toxic dispersants into the Gulf of Mexico as part of their strategy to handle the oil spill for the Deepwater Horizon disaster last April, concerns were raised about the long term effects the dispersants would have on the ecology and food supply in the Gulf region. The chemicals may have simply swept the oil under the rug as opposed to really cleaning up the oil. The chemicals keep the oil off the surface which makes it seem like the oil slick is shrinking. In fact, the oil is merely being deposited in different places where it still does damage.

Pictures of dead shrimp on the ocean bottom are much less damaging on a public relations front than pictures of dead pelicans on the shoreline. The chemical dispersants may have long terms affects on ocean wildlife, and the humans that consume, but those effects are also more likely to be hidden.

The first extensive research into what happened to 770,000 gallons of dispersants used a mile deep near the blown out BP well found a mixed bag of results. The new research appears in the journal Environmental Science & Technology and focused on the fate of the controversial chemicals rather than their toxicity.

Huffington Post reports:
Scientists at the Woods Hole Oceanographic Institution in Massachusetts found circumstantial evidence that the chemicals guided some oil into underwater currents, stopping it from bubbling up to the surface, where it would do more damage, said marine chemist Elizabeth Kujawinski.

That would be considered a good thing, keeping marshes and beaches from getting more tarred, Kujawinski said.

But she added, “the dispersant is sticking around,” which is worrisome. The chemicals didn’t seem to biodegrade the oil and gas as fast as basic chemistry would predict. Her study said the key chemicals in dispersants underwent “negligible or slow rates of biodegradation.” Other studies have found that the oil – not the dispersant – broke apart quickly.

How fast chemicals degrade is important because of potential long-term damage from chronic contamination, she said. And when it comes to the basic question of whether using the dispersants worked, Kujawinski said it is still too early to tell.

Larry McKinney, who directs a Gulf of Mexico research center at Texas A&M University in Corpus Christi, said the government’s use of the chemicals was “successful in avoiding the most serious damage to wetlands marshes. That did work. But there’s likely a price to be paid for that success.”

A federal study last year found that in the short term, dispersant is no more dangerous to aquatic life than oil. However, the long-term effects to aquatic life remain unknown. The new study illustrates how little scientists know about using dispersants in deep water, said Florida State University marine scientist Ian MacDonald.

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