Effects of oil on marine organisms: a critical assessment of publisheddata

Effects of oil on marine organisms are categorized as: (1) direct lethal toxicity; (2) sub-lethal disruption of physiological /behavioral activities; (3) effects of direct coating; (4) incorporation of hydrocarbons; and (5) alteration of habitat, especially substrate character. Occurrence of one or more of these effects depends on the composition of oil to which organisms are exposed. Weathering processes significantly alter the composition of spilled oil, resulting in wide variations in biological effects. A set of oil fractions, distinguished by boiling point range and hydrocarbon type, provide a convenient basis for including the important chemical aspects of the impact problem. Adult marine organisms may exhibit lethal toxic effects from exposures to 1- 100 ppm soluble aromatic derivative hydrocarbons (SAD).Sub-lethal effects may be caused by SAD concs in the range 10-100 ppb. Oil exposed to the atmosphere for 1-2 days loses soluble fractions and non-toxic effects, habitat alteration and coating, become important effects. Effects of several spills are reviewed in light of the above considerations.