Threats from Oil Spills
Spilled oil poses serious threats to fresh water and marine environments. It affects surface resources and a wide range of subsurface organisms that are linked in a complex food chain that includes human food resources. Spilled oil can harm the environment in several ways, including the physical damages that directly impact wildlife and their habitats (such as coating birds or mammals with a layer of oil), and the toxicity of the oil itself, which can poison exposed organisms. The severity of an oil spill's impact depends on a variety of factors, including the physical properties of the oil, whether oils are petroleum-based or non petroleum-based, and the ultimate fate of the spilled oil.
The various types of freshwater and marine habitats that exist in nature have different sensitivities to the harmful effects of oil contamination, as well as different abilities to recuperate. Although some organisms may be seriously injured or killed very soon after contact with the oil in a spill, other effects are more subtle and often longer lasting. For example, freshwater organisms are at risk of being smothered by oil that is carried by the current, or of being slowly poisoned by long-term exposure to oil trapped in shallow water or stream beds. In addition, oil can potentially have catastrophic effects on birds and mammals.