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How Toxic Is Oil?
Assessing the toxicity of oil can be a tricky business. The main difficulty is that "oil" is typically a mixture of many different chemicals. Proportions in the mixture vary even within a single category of oil, like crude oil. For example, Arabian crude oil differs in composition from Louisiana crude oil, which differs from Alaska North Slope crude oil.
It was Alaska North Slope crude oil that spilled from the Exxon Valdez into Prince William Sound. Alaska North Slope crude oil contains many chemicals that can kill a plant or animal outright or cause injury to the extent that it has less chance of surviving in the wild:
- Oiled wildlife often die because oil fouls fur and feathers so that they no longer insulate.
- Smaller organisms can be smothered by a thick layer of oil washing ashore.
- Oil also changes the physical environment for plants and animals by forming asphalt-like pavements, sometimes altering the environment so extensively that the organisms can no longer survive in their old habitat.
The oil from the Exxon Valdez killed or injured in all of these ways. We now know that our attempts to clean up an oil spill can also indirectly cause harm to some of the resources we are trying to protect. For example, using hot water or chemicals to remove oil can harm plants and animals, and simply sending a team of cleanup workers into an oiled area can trample sensitive organisms and mix oil more deeply into a beach. The experts who respond to oil spills consider all of these potential problems when evaluating the trade-offs of how far to go in removing spilled oil.
Other Pages in this Series
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