Distribution and recovery trajectory of Macondo (Mississippi Canyon 252) oil in Louisiana coastal wetlands

• Published in: Marine pollution bulletin 2014-10, Vol.87 (1-2), p.57-67
• Main Authors: Turner, R. Eugene, Overton, Edward B., Meyer, Buffy M., Miles, M Scott, McClenachan, Giovanna, Hooper-Bui, Linda, Engel, Annette Summers, Swenson, Erick M., Lee, James M., Milan, Charles S., Gao, Heng
• Format: Article
• Language: English
• Subjects: Alkane; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Ecotoxicology, biological effects of pollution; Environmental degradation: ecosystems survey and restoration; Fundamental and applied biological sciences. Psychology; Louisiana; Macondo oil spill; Marine; Marine and brackish environment; Mississippi; PAH; Petroleum - analysis; Petroleum Pollution; Polycyclic Aromatic Hydrocarbons - chemistry; Recovery; Restoration; Sea water ecosystems; Synecology; Water Pollutants, Chemical - chemistry; Wetland; Wetlands
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2014.08.011

•We measured oil in wetlands before and after the 2010 Macondo oil spill disaster.•Alkanes and PAH concentrations were 604 and 186 X the baseline values, respectively.•Oil was found at least 100m inland from the shoreline and without much attenuation.•Alkanes may be at baseline concentrations by 2015, but take many decades for PAHs. We measured the concentration of petroleum hydrocarbons in 405 wetland sediment samples immediately before the April 2010 Deepwater Horizon disaster led to their broad-scale oiling, and on nine trips afterwards. The average concentrations of alkanes and PAHs were 604 and 186 times the pre-spill baseline values, respectively. Oil was distributed with some attenuation up to 100m inland from the shoreline for alkanes, but increased for aromatics, and was not well-circumscribed by the rapid shoreline assessments (a.k.a. SCAT) of relative oiling. The concentrations of target alkanes and PAHs in June 2013 were about 1% and 5%, respectively, of the February 2011 concentrations, but remained at 3.7 and 33 times higher, respectively, than in May 2010. A recovery to baseline conditions suggests that the concentration of alkanes may be near baseline values by the end of 2015, but that it may take decades for the PAH concentrations to be that low.