ABSTRACT
Light Crude Oil The American Petroleum Institute characterizes crude oil both by geographic source (e.g., Louisiana sweet crude) and by physicochemical attributes (e.g., class A light crude oil). The Louisiana sweet crude oil spilled in the Deepwater Horizon disaster is a class A, volatile crude oil, and is the highest-quality crude oil, which requires the least amount of rening into fuels and other petrochemicals. Light crude oils are clear colored with a strong odor and high volatility and ammability. Light crude oils can be washed off surfaces, but will deeply penetrate porous surfaces, such as dirt and sand, and become persistent in the environment. They are
lighter than water (lower specic gravity) and oat on the surface, where they evaporate rapidly in sunlight. As the VOCs in light crude oils evaporate, the surface oil will lose 20-40% of its volume and become denser and more viscous forming oating mats. Some of this weathered crude will dissolve in the water column to form a thick mousse and other dense particles will congeal and sink forming tar balls that may be washed ashore by wave action. Although consumed by several species of marine bacteria, light crude oils may be highly toxic to humans, sh, and higher benthic organisms.
