Mar 03 2010
SOURCES… Oil spills’ sources can be both point source pollution and non-point source pollution. Several sources of oil spills include: offshore wells (these usually contribute to “blowouts” or the leakage of oil due to high pressure), tanker wrecks (such as the Valdez), pipelines, storage tanks, and runoff from highways. Runoff from highways is thought to be one of the leading sources of oil ocean pollution. *Below is a picture of the Alaskan pipeline.
IMPACTS… There are numerous direct and indirect effects of oil spills on ocean ecosystems: the death of many ocean-dependent organisms, the loss of animal insulation and buoyancy (like the coating of oil on birds’ feathers or otters’ coats), and the smothering of aquatic organisms (such organisms like crabs, oysters, and mussels settle at the bottom of the ocean where the more dense parts of a crude oil mixture sink). Oil spills can be especially destructive toward the ocean ecosystem because the bottom levels of the food chain are affected not long after the spill (for example: microorganisms like zooplankton). Other impacts can include those on coastal communities that depend on the ocean for food (seafood consumers) and income (fishermen and areas that count on tourist activity). *Below is a picture of a bird covered with oil.
At this point in class, we watched a movie produced by Exxon in 1992 (just three years after the Valdez oil spill); it was titled: Scientists and the Alaska Oil Spill. The video was pretty keen on ensuring the audience that scientists and experts were on sight to carry out a proper cleanup and recovery for Prince William Sound. The main focus of the Exxon video was cleanup and recovery of the oil spill- it mentioned several impacts of the spill as well as what had been to to help the ecosystem recover. There were some scientists who encouraged the cleansing of the environment on its own and letting nature do its work by itself. Other points of view recommended that we help out some way to kick-start cleanup of the environment. Below is a short video clip that’s great recap of the Exxon movie as well as the chapter “Oil on the Rocks” in Watersheds 4 focusing on the environmental recovery aspect of an oil spill.
CLEANUP… It’s said that most ecosystems can recover from crude oil spills in about three years, but recovery from refined oil spills may take up to ten through twenty years. There are three general categories of cleanup: 1) mechanical, 2) chemical, and 3) biological. Mechanical cleanup methods include: booms (large floating containment barriers that lift oil out of ocean water), skimmers (way of skimming the surface of the water to lift oil out), and blotters (thick sponge-like device that can “blot up” oil from the surface of the water). Chemical cleanup methods include: dispersing agents (they’re essentially detergents that divide or disperse the oil) and coagulants (these do the opposite of dispersants- instead of breaking up the oil, these concentrate the oil). Lastly, Biological cleanup methods include bioremediation (uses naturally occurring microbes to consume the hydrocarbons of oil).
Here is a link to a website with some awesome descriptions of oil spill cleanup methods: http://science.howstuffworks.com/cleaning-oil-spill.htm
Here is a link to the EPA’s A Citizen’s Guide to Bioremediation: http://www.epa.gov/tio/download/citizens/bioremediation.pdf . I found this particularly helpful in understanding the concept of bioremediation as a means of cleaning up oil spills. Below is a cartoon version of bioremediation:
SOLUTIONS… Well the most effective solution would be to discontinue our use of oil, but that is impossible for our oil-dependent world. We can, however, improve standards for the transportation of oil; keep people and tankers away from reefs; use double hulls on tankers; increase the intensity of penalties for oil spills and tanker accidents; create new methods of cleanup; and introduce legislation such as the Oil Pollution Act. Here is link to a summary of that act from the EPA: http://www.epa.gov/lawsregs/laws/opa.html.