Scientists Determine Source of Dispersant Chemicals Found in Community-Led Water Study

Locations of water samples for dispersant-related constituents conducted by EPA. Image from Hayworth’s paper.

(Click to enlarge) Locations of water samples for dispersant-related constituents conducted by EPA. Image from Hayworth’s paper.

After the oil spill, the City of Orange Beach, AL collected water samples and contracted commercial laboratory analysis “for chemical constituents associated with the Deepwater Horizon event.”  Their results showed the presence of dispersant-related chemicals.

Auburn University scientists examined the data to determine the chemicals’ origin and concluded that “they are likely related to point and non-point source stormwater discharge.”  The researchers published their findings in the October 2012 issue of the Marine Pollution BulletinProvenance of Corexit-related chemical constituents found in nearshore and inland Gulf Coast waters.

Local municipalities in Alabama concerned about environmental impacts from the oil spill “conceived and executed at the community level” their own monitoring and sampling efforts. Between September 2010 and January 2011, they collected 56 water samples from 13 locations in Perdido Bay and along the shoreline in and around the City of Orange Beach.  Two accredited laboratories in Minnesota and Washington found “positive detections of propylene glycol, 2-butoxyethanol, and DOSS,” chemicals found in Corexit dispersants. These results started a debate about the original source – which has potential legal implications – of these chemicals, primarily because: (1) this community was impacted by the oil spill, (2) these chemicals are commonly found in many commercial and common household products, and (3) Orange Beach lies within the Perdido Bay Watershed, which receives runoff from urban development, agriculture, industry, waste sites, and military facilities.

Auburn University scientists considered prior studies on toxicity and alternate sources of these chemicals as well as previous studies on the direction and distance that dispersant-related chemicals travelled as they dispersed from the wellhead.  They also looked at the proximity of sample sites to stormwater drains and rain events during that time. The researchers concluded that the chemicals in Orange Beach water samples “did not originate from the use of Corexit dispersants during the Deepwater Horizon accident response” and that these compounds were present as a result of “stormwater discharge related to rainfall events.” In their discussions, the researchers noted that these compounds “are not part of routine water quality monitoring programs” and suggested that the oil spill may have provided an “unfortunate motivation” to look into and increase community awareness about the presence of these compounds in coastal waters.

The study authors are Joel S. Hayworth and T. Prabakhar Clement (Marine Pollution Bulletin, 2012, 64, 2005-2014).

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This research was made possible in part by a Grant from BP/The Gulf of Mexico Research Initiative (GoMRI) through the Alabama Marine Environmental Science Consortium (MESC). Other funding sources included the National Science Foundation.

The GoMRI is a 10-year independent research program established to study the effect, and the potential associated impact, of hydrocarbon releases on the environment and public health, as well as to develop improved spill mitigation, oil detection, characterization and remediation technologies.  An independent and academic 20-member Research Board makes the funding and research direction decisions to ensure the intellectual quality, effectiveness and academic independence of the GoMRI research.  All research data, findings and publications will be made publicly available.  The program was established through a $500 million financial commitment from BP.  For more information, visit http://gulfresearchinitiative.org/.   

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