Sensitivity of modeled oil fate and exposure from a subsea blowout to oil droplet sizes, depth, dispersant use, and degradation rates. (September 2019)

• Record Type: Journal Article
• Authors: French-McCay, Deborah; Crowley, Deborah; McStay, Lisa
• Is Part Of: Marine pollution bulletin. Volume 146(2019)
• Page Start: 779
• Page End: 793
• Publication Date: 2019-09
• Subjects: Oil spill modeling -- Oil and gas blowout -- Net environmental benefit analysis -- Spill impact mitigation assessment -- Oil spill response -- Subsea dispersant injection; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2019.07.038
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: As part of a Comparative Risk Assessment (CRA) developed and reported previously, oil spill modeling of a hypothetical blowout at 1400 m in the northeastern Gulf of Mexico was performed to evaluate changes in oil exposures with alternative response options, i.e., combinations of mechanical recovery, in-situ burning, surface dispersant application and subsea dispersant injection (SSDI). To assess if conclusions from this study could be extended to other spill scenarios, sensitivities of the predicted oil fate and exposure metrics to location, release depth, oil and gas flow rate, gas content, orifice size, oil droplet size distribution, and biodegradation rates were examined. Results show that the fraction of oil surfacing is highly sensitive to oil droplet size distribution and depth of release. Across the simulations performed, SSDI use reduced oil droplet sizes released, thereby mitigating surface and shoreline oiling, volatile hydrocarbon exposures, and potential surface water column exposures. Graphical abstract: Unlabelled Image Highlights: Varied influential inputs for comparative analysis of oil spill response options Oil hydrocarbon exposures are sensitive to oil droplet size distribution. With smaller droplet sizes, the amount of surfacing oil decreased. Reduced droplet sizes increased rate of oil dissolution and biodegradation in water. Dispersant-reduced droplet sizes decreased human, wildlife and shoreline exposures.