Deepwater Horizon Oil Washes Ashore Years After the Spill

The Deepwater Horizon oil spill was one of the worst environmental disasters of its time. Now, even years later, oil continues to wash ashore as oil soaked "sand patties." These recent findings raise questions about how much oil has been deposited on the seafloor, and how long we'll continue to see the impacts of this spill.

"We were looking at two questions: how could we identify the oil on shore, now four years after the spill, and how the oil from the spill was weathering over time," said Christoph Aeppli, one of the researchers, in a news release.

In order to answer these questions, the researchers used a comprehensive two-dimensional gas chromatography in order to measure the levels of degradation in biomarkers. Biomarkers can allow researchers to identify exactly which reservoirs the oil came from. Oil consists of tens of thousands of compounds, and many of them are degraded by bacteria or broken down by sunlight. This research in particular determined the resiliency of specific biomarkers and saw how they held up when exposed to environmental conditions on shore.

"We found that some biomarkers-homohopanes andtriromoatic steroids (TAS), specifically-degraded within a few years following the Deepwater Horizon spill," said Chris Reddy, one of the researchers, in a news release. "These biomarkers are not as resilient as once thought and they may provide a future window into determining how much, and how quickly, these oil components may linger in the environment when exposed to air, sunlight, and the elements."

The findings reveal a bit more about this oil spill and show exactly how long these compounds might persist in the environment. This can improve oil spill forensics to help researchers if future oil spills are to occur. In addition, it allows scientists to track oil exposure.

The findings are published in the journal Environmental Science & Technology.