Tanker accidents:
The most publicized of the oil spills are those caused by tanker accidents. There have been hundreds of accidents involving the spilling of mil-lions of tons of oil.
Big oil spills, regardless of the way they occur, reflect poorly on the oil industry. The clean-up cost alone is enormous, and compensa-tion for damages can run into millions of dollars. Despite the best clean-up efforts, once an oil spill occurs, it cannot be prevent-ed from causing major dam-age to the environment and wildlife.
Effect on wildlife
Migrating seabirds like puffins, guillemots, and razorbills are particularly at risk from oil pollution. During migration, they look for areas of calm water on which to rest or hunt for fish. Oil-covered seas appear calm to the birds, and they land on the water by the thousands, only to become trapped in the sticky sub-stance and die of starvation. The birds that do not become trapped usually die as well. As they try to remove the oil from their feathers with their bills, the birds ingest the high-ly toxic substance, which kills them within a few days.
Oil that has washed ashore on beaches where seals and sea lions breed and haul out (rest on shore) can harm these animals as well. While they may survive being somewhat covered with oil, animals that are caught in the oil slick generally die.
An area that is especially rich in wildlife is Alaska’s Prince William Sound. As a result of the Exxon Valdez oil spill in 1989 (see back cover), thousands of sea otters have died and 10,000 more are currently at risk. When oil coats their fur, otters are unable to swim or maintain their body temperature, and they either drown or freeze to death.
Marine animals killed by oil are in turn eaten by other species. Thus, the poisons work their way up the entire marine food chain.
Cleaning up
The problem of how to completely and effectively clean up oil spills has yet to be solved. The effectiveness of the techniques currently used depends on weather conditions and the location of the spill. Rough seas can be helpful in breaking up oil slicks, but they can also churn the oil and seawater together, forming a sub-stance that is harder to dis-perse than crude oil itself.
Crude oil is a complex, highly variable mixture of more than a thousand differ-ent chemicals. In most seas, the highly toxic light hydro-carbons, which are generally refined into gasoline and jet fuel, soon evaporate, reduc-ing some of the risk to marine life. However, in freezing Arctic and Antarctic waters, the process of evapo-ration is slow due to the extremely low temperatures; consequently, there is more danger to wildlife. Under these conditions, the oil must be burned.
In calm waters, long, float-ing booms can help to con-tain the oil so that it can be pumped off the surface of the sea into holding tanks. After as much of the oil as possible is removed, disper-sant chemicals are sprayed by air on the remainder of the spill. The chemicals break down the oil into tiny parti-cles, which are further bro-ken down by bacteria that feed on some of the hydro-carbons contained in oil. Still, much of the residue will eventually wash up on beaches.
Major tanker disasters
The Torrey Canyon.
Great Britain, March, 1967. First of the huge oil spills. The Torrey Canyon ran aground and unleashed 116,000 tons of oil on nearby rocks and beaches. Birds died by the thousands. The puffin population on the Sept Isles off of France was virtually exterminated.
The Amoco Cadiz.
Brittany, France, 1978. Following en-gine failure, the Amoco Cadiz was wrecked on Brittany’s rocky coastline. Thousands of migrating seabirds were killed as they landed on the oily water. Numerous oyster beds were destroyed as well.
The Exxon Valdez.
Alaska, March, 1989. This huge super-tanker was mistakenly steered onto the rocks along the Prince William Sound. Exxon, the State of Alaska, and federal government agencies were
slow to get clean-up equip-ment on the scene. The delay allowed 232,000 barrels of oil to spread over a large portion of the sound, a pristine area previously rich in all kinds of wildlife.
What can be done?
Some of the worst oil pollu-tion is caused by the cleaning of ships’ oil storage tanks at sea. Stricter policies regarding this type of activity must be enforced. Every year, a quanti-ty of oil equal to the amount spilled by the Torrey Canyon is released in the North Sea through the disposal of petro-leum products-both at sea and on land.
A vast amount of oil seeps into the oceans by way of sewers and rivers. One way people can reduce oil pollu-tion is by returning used motor oil to the garage for recycling, rather than pouring it down the drain or burying it in the yard.
