Ghosts of Deepwater Horizon oil spill still haunt the ecosystem

Researchers from Louisiana State University have discovered that oil spilled during the Deepwater Horizon tragedy was still present in the ecosystem ten years later, although the environment significantly altered it. The study, published in the journal Frontiers in Marine Science, details how the scientists tracked the various components of leaked crude oil. 

Study first author Professor Edward Overton said that knowing how the chemicals interact with the environment can aid us when the next inevitable spill occurs.

“Our paper describes the most abundant chemicals that make up typical crude oil and their potential fates in the environment,” said Professor Overton.

“The better we understand the chemicals and their chemical reactive properties as well as their physical properties, the better we will be able to mitigate oil spills and understand and detect environmental damages from oil spills,” 

The researchers analyzed the most concentrated and toxic chemical components released during the spill. From 2010 to 2020, they collected samples from the shoreline, water, and seafloor.

The study revealed that 30-40 percent of the spilled oil evaporated into the air and that water-soluble chemicals were dissolved and degraded by aquatic organisms. Moreover, these solar-dependent processes degraded a lot of the oil. However, there were still components left in the environment for at least ten years. 

“The important point about oil spills is that the oil’s compounds are a type of material that can be degraded by sunlight and marine bacteria (biodegradation), in contrast to other types of pollutants such as the chlorinated pesticides like DDT,” explained Professor Overton. “Oil spills release lots of chemicals quickly and most damage from oil spills occurs fairly soon after the spill.”

However, the chemical processes that break down oil are not universal, and more research is necessary.  

“Environmental circumstances surrounding specific spills greatly affect how quickly the compounds can react, what they cover or coat and how much oxygen can be taken up in critical habitats,” said Overton.

“Therefore, broad generalization about oil spills requires understanding what was spilled and what are the environmental conditions of the spill. Hopefully this paper will help expand our understanding of the types of chemicals that are found in oil and their ability to cause environmental damages.”

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By Erin Moody , Earth.com Staff Writer