Unified Area Command releases report on oil monitoring data and analyses

Posted on December 20, 2010

On Friday, the Unified Area Command (UAC) released a report from the Operational Science Advisory Team that summarizes the results of the extensive sampling efforts conducted by the subsurface monitoring program.  Federal On-Scene Coordinator (FOSC) Capt. Lincoln Stroh will use the findings of the report to direct further operations to find and recover oil.

The report found tar mats in shallow subtidal areas near the shore and traces of oil in deep-sea sediments within approximately 6 miles (10 km) of the wellhead.  As a result, Capt. Stroh has directed response teams to focus assessment and potential cleanup efforts in the very nearshore areas.  The oil found entrained in the deepwater sediments was found by the FOSC to be not recoverable; however, the report recommends further monitoring of these deep-sea sediments as part of the Natural Resource Damage Assessment process.  The OSAT report is operational in nature, designed to guide the response, and is not intended to draw conclusions about the impact or damages caused by the spill.

The sampling data showed no deposits of liquid phase oil from the spill in sub-surface sediments beyond the shoreline; no exceedances of EPA’s human health benchmark; and no exceedances of EPA’s dispersant benchmarks. The report also found that, since August 3, 2010, <1% of water samples and ~1% of sediment samples exceeded EPA’s aquatic life benchmarks for polycyclic aromatic hydrocarbons (PAH).  None of the water samples were consistent with MC-252 oil. The sampling confirmed that MC-252 oil exists in the bottom sediment in the vicinity of the well head with oil concentrations between 2 and 5 parts per trillion. All of the sediment samples containing PAHs exceeding the benchmarks were taken within 2 miles (3 km) of the well head.  Sediment samples with PAH levels below benchmarks but above reference concentrations were found as far as 6 miles (10 km) from the well head. 

“Science has informed the Federal response since the earliest moments of this crisis and will continue to contribute to the NRDA process.  This report, the result of an impressive amount of rigorous study and around-the-clock work by federal and independent scientists, provides the most complete data set available about the conditions in the vicinity of the BP Deepwater Horizon well,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator.  “There are still many unanswered questions about the extent of the impact of this spill and we remain committed to holding the responsible party accountable through a careful and rigorous natural resource damage assessment process.”

The report was reviewed by the Federal members of the Joint Analysis Group, and all the data that were analyzed for the purpose of this report are now available on RestoreTheGulf.gov and Geoplatform.gov.

The Subsurface Monitoring Unit’s charge was to undertake an intensive scientific survey of the Gulf of Mexico and conduct a comprehensive, thorough analysis of the water and ocean floor to assess the distribution and concentration of oil released by MC-252 and dispersant used in the response efforts.  Scientists from five federal agencies and BP participated in the design, collection, analysis, and interpretation of the data.  The Federal agencies were the USCG, NOAA, USGS, EPA, and Bureau of Ocean Energy Management, Regulation and Enforcement.