MMS ENVIRONMENTAL STUDIES PROGRAM:  ONGOING STUDIES

MMS OCS Region:

Gulf of Mexico

Title:

Determination of Net Flux of Reactive Volatile Organic Compounds at the Air-Water Interface in the Gulf of Mexico (GM-92-42-116)

Planning Areas:

Central and Western

Total Cost:  $145,059

Period of Performance:  FY 2005-2008

Conducting Organization:

Coastal Marine Institute, Louisiana State University

MMS Contact:

Dr. Margaret C. Metcalf

Description:
Background:  Reactive volatile organic compounds (RVOC) are a group of gases with both natural sources and sources related to human activities.  On the floor of the Gulf of Mexico, these gases are released to the water from naturally-occurring seeps.  Biogenic sources are also a source of RVOCs.  These light, organic gases may volatilize from water to the air where they may eventually interact with other compounds in the air to form pollutants such as ozone.

Ozone levels exceed USEPA regulatory levels in several cities along the Gulf of Mexico coast and state environmental agencies continue to monitor the causes and implement controls on sources.  An improved estimate of the amount of naturally-occurring RVOC would be useful in determining source contributions to degraded air quality in these adjacent cities.

Objectives:  The objectives of this study are to:

·                    develop and validate a sampling and analytical methodology to measure a range of naturally-occurring RVOCs in air and water;

·                    using both field and laboratory methods, determine the concentrations of RVOC in air and water samples from pertinent locations near oil and gas seeps; and

·                    generate emission factors for various settings and environmental conditions that can be correlated with remote sensing techniques.

Methods:  Tasks will be conducted in both the LSU Department of Environmental Sciences (DES) laboratory and various sample locations within 10 to 50 miles South of Port Fourchon in the MMS central planning area.

At LSU DES, the analytical methodology will be refined.  Five sampling trips are planned.  Air and water samples will be collected and analyzed for RVOCs.  Sampling locations will be selected based on the presence of naturally-occurring oil and gas seeps, faulting zones not associated with any known macroseeps, and corresponding control locations at a specified distance from a seep.  Multiple samples at varying water depth or air height will be collected at each location.  Surface meteorological conditions will be monitored during the sampling period.

Products:  Products to be delivered to MMS include quarterly status letters, a final report and a PowerPoint slide presentation.

Importance to MMS:  The responsibility for air quality management in the Western/Central Gulf of Mexico has been delegated to the Minerals Management Service (MMS).  The possibility that air quality problems in regional onshore urban areas are partially due to downwind transport of RVOC emitted in the Gulf makes the quantification and characterization of emissions in the Gulf of Mexico an item of interest to MMS.

Current Status:  The contract was awarded in September 2004.  Essential instrumentation was acquired in July 2005.  Several investigators were diverted to Hurricanes Katrina and Rita cleanup and site assessment activities during the latter months of 2005.  The contract was modified in March 2006 and October 2007 to provide additional time.  During 2006, progress was made on sampling and analytical methods including determination of the best absorbent resin combination to trap the study compounds, the correct sampling flow volume, the desorption methodology, and on-scene and laboratory analytical methodologies.  The procedure was successfully field-tested at a pipeline site near Baton Rouge.  One sampling cruise has been conducted but curtailed due to the lack of availability of suitable charter vessels and poor weather. Additional scheduled sampling trips have been delayed by uncooperative weather and the sensitivity of the instrumentation to rough seas.

Final Report Due:

June 2008

Publications:

None

Affiliated WWW Sites:

None

Revised date:

March 2008

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