Monitoring Effects of Aerial Dispersant Application during the MC252 Deepwater Horizon Incident

ABSTRACT The MC252 Deepwater Horizon (DWH) incident released large volumes of oil which threatened marine wildlife and sensitive coastal habitats. Response strategies to reduce the impact of the oil included mechanical removal, controlled burning, and use of dispersants. Dispersants were applied by aerial spray from low-flying aircraft, by boat spray on the water surface for volatile organic compound (VOC) control and for effectiveness testing, and by subsurface injection into oil released at the wellhead. Monitoring of dispersant effectiveness and potential environmental impact following aerial and vessel application was conducted by the M/V International Peace. Visual observations, fluorometry tows and water quality measurements were made before and after surface dispersant application. Water samples were collected for analytical characterization and toxicity testing at 1 and 10 meter depths below the slick prior to and following dispersant application to evaluate the distribution of the dispersed oil t...