A discussion of limitations on dispersant application

Dispersants have been used with mixed success since the Torrey Canyon incident in 1967. Although in recent years the use of mechanical recovery methods has been increasing, dispersants still continue to be the main method ofpollution control in many countries. This paper presents a discussion on the limitations of dispersants and provides criteria for determining whether the dispersant approach will provide an acceptable means of treating a particular spill. It concludes that, non-spreading high viscosity oils, water-in-oil emulsions and oil slicks in the final phases of spreading, i.e. very thin slicks, are effectively non treatable with dispersants. It also suggests that as an alternative to dispersant treatment for dispersible oils, consideration should be given to increasing natural dispersion rates by agitation from the passage of boats through the slicks.