What are some long term effects of oil spills?

Answer 1

The effect depends on where the spill takes place. If on a body of water oil would float having a lighter specific gravity and would cause damage to plankton and other animals living in the upper water zone. The COD or chemical oxygen demand of the contaminate would kill of fish food supplies. Birds would get covered in oil and eventually die due to exposure or oil ingestion. Oil could be carried to shore effecting fish fry breeding grounds, oyster, mussel beds and shore creatures crabs and so on. Oil Aggregates could form and these balls of oil can be carried far and wide eventually sinking to the sea floor.

Answer 2

Some simple questions do not have simple answers. This is one of them.

Most marine oil spills will disrupt the ecosystem of the area and it is generally concluded that these impacts will last far longer than the visual disappearance of the water's surface. But the conditions of spills and the amounts of oil spilled vary greatly, so it is hard to know what the long term impact (10 years plus) of many oil spills, including the BP oil spill.

The Exxon-Valdez spill may be the most studied oil spill in the world, and scientists still have been unable to agree on long term effects. See the excerpt from the Wikipedia link:

"Some twenty years after the spill, a team from the University of North Carolina found that the effects were lasting far longer than expected.[27] The team estimates some shoreline Arctic habitats may take up to thirty years to recover.[clarification needed][8] Exxon Mobil denies any concerns over this, stating that they anticipated a remaining fraction that they assert will not cause any long-term ecological impacts, according to the conclusions of 350 peer-reviewed studies.[28] However, a NOAA study concluded that this contamination can produce chronic low-level exposure, discourage subsistence where the contamination is heavy, and decrease the "wilderness character" of the area.[23]"

In the particular case of the Exxon-Valdez oil spill, if you read through the press release from the University of North Carolina, you will learn more on the long term effects. Oil contains toxic chemicals, particularly the aromatics (benzene is a good example) which is harmful to marine life. In the case of the Alaska spill, the damage was caused to the salmon eggs. This can impact other marine life in Alaska.

There must be sufficient concentration of oil in the water for environmental damage to occur. Over time, sunlight, bacteria and wave action all work to reduce the toxic effects of the oil. But as stated in the UNC study, there may be areas where the oil has been "sequestered" or isolated pools of oil, so the normal decomposition does not occur and the toxic effects are much more long lasting.

There is the UNC study, reported in Science journal in 2003 (may be found in your library), and a NOAA study, which you may find by searching the internet. You may also examine the oil spill following the Kuwait war oil spill. It is controversial whether there is any long term effects (10 years plus) from this spill.

See related links.