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Environmental Health - Toxic Substances


Natural Attenuation of Fuel Oxygenates -- Laurel Bay, South Carolina Site [Completed]

Discharge area
Ground-water at the Laurel Bay Site discharges to this concrete-lined drainage ditch where highly efficient biodegradation takes place in the sediments under the ditch.
Project Bibliography
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Methyl tertiary-butyl ether (MTBE) is just one of the hundreds of compounds in gasoline that we pump into cars across this Nation every day. However, MTBE can comprise up to 15% by volume of gasoline and is highly soluble in water. As such, releases of gasoline containing MTBE to ground-water systems at leaky underground storage tank (LUST) sites are often characterized by MTBE concentrations that are considerably higher than those of either benzene or toluene, the most soluble aromatic hydrocarbons in gasoline (each about 1 - 2% of gasoline). As a result of this higher solubility and volume, plumes of MTBE contamination in some ground-water systems can often be over 1,000 ft long.

Since 1993, a team of USGS researchers have examined the natural attenuation and fate of MTBE from this spill with emphasis on:

  • Comparing the transport and fate of MTBE with the most mobile aromatic petroleum hydrocarbon (benzene);
  • Determining if the biodegradation of MTBE leads to the production of intermediate breakdown compounds, such as tertiary butyl alcohol (TBA);
  • Evaluating behavior under oxic and anoxic conditions, including naturally occurring, hydrologic redox interfaces, such as where anoxic ground water containing MTBE discharges to oxic surface-water systems;
  • Designing artificially engineered redox interfaces, by injecting oxygen reactive compounds to anoxic aquifers containing MTBE;
  • Characterizing transport and natural loss of MTBE vapors through the unsaturated zone; and
  • Understanding the potential for trees growing above an MTBE plume (using this gasoline-contaminated ground water as a source of transpirational water) to remediate MTBE plumes.

The knowledge gained at the Laurel Bay site has been tested at MTBE contamination sites across the Nation.

Sourc area
A leaking underground storage tank at the Laurel Bay site was located behind the gasoline station to the far right, and the oak trees.

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Additional Research at the Laurel Bay Site

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Page Last Modified: Monday, 27-Jun-2016 07:27:14 EDT