Oil is made up of thousands of chemicals that can be placed into four groups: saturates, aromatics, resins, and asphaltenes (referred to as SARA). “Light oil” generally contains more saturates and aromatics, while “heavy oil” contains more resins and asphaltenes. However, for most crude oils, the saturates and aromatics make up a larger portion of the entire composition on a mass basis. The physical, chemical, and biological properties of these components dictate their overall environmental fate in an oil spill situation.
