Presentation
Potential Field Exposures and Aquatic Toxicity to Inform Response Activities, Impact Evaluations and Oil Toxicity Research Needs
DescriptionThe biological effects of oil on aquatic biota are of concern for spill planning, response decision-making (e.g., consideration of dispersant use), risk assessments, impact evaluations, and natural resource damage assessment. For a range of spill and oil types under different environmental conditions, oil transport and fate modeling was used to quantify expected exposures for aquatic organisms. Volumes of water affected above thresholds of concern and toxicity modeling show that for surface spills, considerable wave-driven turbulence and/or dispersant use on fresh oil (weathered <24 hours) is needed to generate exposures that might cause toxic effects. Pipeline releases are generally low turbulence releases, such that the oil surfaces rapidly, and exposures are similar to surface spills. In contrast, oil released from subsea blowouts entrains directly into the water. Aquatic exposures and effects are higher with smaller oil droplet sizes, resulting from higher turbulence releases (e.g., higher flow rates of oil and gas) and when dispersant is applied. Alternatively, for low oil and gas flow rates most of the oil surfaces rapidly because oil droplet sizes are larger, which reduces water column exposure and toxicity. Higher current speeds mitigate exposure by diluting the dissolved oil plume.
In addition to oil properties, oil composition, and environmental conditions determining exposure and effects, potential aquatic effects are subject to organism sensitivity, behavior of the individual, duration of exposure, light exposure (for vulnerable species and life stages), and potentially other factors such as temperature, and salinity. The most influential of these factors determining the volume of water where aquatic biota would be adversely affected are organism sensitivity and duration of exposure. Phototoxicity would also be important for small clear-bodied plankton. Considering these factors and model results informs response decision-making regarding the use of dispersants at the surface and subsea, as well as impact assessments.
In addition to oil properties, oil composition, and environmental conditions determining exposure and effects, potential aquatic effects are subject to organism sensitivity, behavior of the individual, duration of exposure, light exposure (for vulnerable species and life stages), and potentially other factors such as temperature, and salinity. The most influential of these factors determining the volume of water where aquatic biota would be adversely affected are organism sensitivity and duration of exposure. Phototoxicity would also be important for small clear-bodied plankton. Considering these factors and model results informs response decision-making regarding the use of dispersants at the surface and subsea, as well as impact assessments.
Authors
Scientist III - GIS Analyst
Event Type
Paper
TimeThursday, May 16th8:00am - 8:20am CDT
Location291-292
Preparedness
Response