USF study: 'Substantial' amount of Deepwater Horizon oil still lives on in the environment

It's been exactly 10 years since the Deepwater Horizon disaster, a deadly accident on an oil rig in the Gulf of Mexico -- and to this day it is still having an effect on the environment. In fact, researchers with the University of South Florida's College of Marine Science found oil from a spill that occurred in 1979.

Dr. Steve Murawski, with the USF College of Marine Science, said for the past decade, he, along with other USF researchers, have been studying the environmental effects of the Deepwater Horizon oil spill. 

Sporadically, he said, they would travel to the northern areas of the Gulf to measure the amount of oil in fish and sediments.

"One thing that we found is there is a substantial amount of that oil that is still in that environment, in the deep sea and then up in the Louisiana marshes," urawski explained. "So, it continues to contaminate and has toxic effects."

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The USF team surveyed 15,000 fish, and scientists detected oil exposure in all of them.

However, he said, if you catch a fish, and there is oil found in it, it may not necessarily be from the BP oil spill in 2010.

"It's probably not the Deepwater Horizon oil down there," Murawski said. "There are a lot of multiple sources of oil. Obviously we have a very large oil industry and there's small leaks and pipeline breaks and whatnot."

PHOTOS: Coast Guard team flies over Deepwater Horizon site (2010)

USF marine scientists say the highest levels of oil exposure were detected in yellowfin tuna, golden tilefish and red drum.

Parts of that oil can come off the land, too.

"We found a hotspot off of Tampa Bay, which is probably related to marine oil and burning of gasoline in boats," Murawski said. "This baseline helps us disentangle the effects of Deepwater Horizon from all the other sources."

Another one of those sources is an oil spill that occurred in 1979. Murawski said his team found remnants of that oil at the bottom of the Gulf.

"Back in 1979-1980, there was a massive oil spill off the Campeche region in Mexico. That leaked for nine months. It was about two-thirds the size of Deepwater Horizon," he said.

The discovery helped the team of USF researchers create projections of where Deepwater oil would be 30 to 40 years from now. 

"From those studies we can extrapolate that the Deepwater Horizon oil will be with us in some form in the marshes and in the deep sea," Murawski explained, "for another 30 years."