Oil spills are a growing concern for the world’s coasts. With the increasing demand for oil there is also an increase in the number of tankers and oil wells in our oceans. Many oil companies are turning to offshore drilling because of the availability of oil just below the ocean floor. But what happens when something goes wrong? When there is an oil spill, it is a very serious concern not only for the environment but for the living animals as well as our beaches. The longer a spill is left without treatment or cleanup, the more harmful the effects are. If the oil reaches the coastal beaches, it is the hardest to clean up. The oil can glob together and create little tar balls which stay in the sand for long periods of time.
Very little was known about the effects of oil buried deep in the sands of beaches, until recently when the effects could be seen. After the prestige oil spill of 64,000 tons of fuel-oil occurred off the north Atlantic coast of Spain in November 2002, 786 of 1064 beaches along that coast were affected.
Luckily a rapid response helped to clean up most of the surface oil and beaches. But what was left over is now being trapped underneath the surface sand of the beaches and is not reached by the natural cycle of erosion.
In the experiment done by Bernabeu et al., the process of degradation of the tar ball was observed and simulated. PVC tubing cut in half was sealed with a transparent plate in order to view the process. This was then filled with sand and a tar ball buried about halfway in the sand. To simulate wave action, filtered seawater was introduced into the halved pipe and then drained. Because the tar ball would normally be underground without light, the PVC tube was covered with an opaque cloth to prevent photooxidation.
Over a 130 day period, the oil was found to have leached out slowly. This supports the emulsification process theory and shows that oil spills are not only harmful at the start of the spill but continue to damage the environment in the long-run.
This experiment made possible an estimation of the effects of different physicochemical factors on the process of degradation of buried oil. After 130 days of observation and experimentation, the tar ball seemed to have dispersed to have a halo around it which indicates that the buried oil starts to break down. This process of emulsification has a sequence that causes the oil and water to break apart. These oil particles disperse and are then washed away by the flow of water. This process helps to gradually eliminate some of the oil form the microcosm. This, however, in many cases is not possible because the natural processes often cover the tar ball. However it may be possible for waves to remove the tiny particles that separate from the tar ball. This process could take many years. Waters’ salinity (present in the oceans), plays an important role in the emulsification process of the tar ball. The salt helps to break apart the tar ball so that the small particles can be removed by wave action. If this process were as effective in real life as they were in the lab, then the tar balls would be degrading at a much faster rate than they are currently. But this process is difficult to control in real life and some areas of tar balls are buried under as much as three meters of clean sand.
Now that we know the lasting effects of an oil spill, hopefully we can learn from our past mistakes. There is no quick-fix to an oil spill, the best way to prevent the increasingly common spills is to try and reduce our amount of oil consumption and shipping.
Bibliography
(2002, November). Retrieved October 13, 2010, from IBRRC: http://www.ibrrc.org/research_clean_agents.html
Bernabeu, A., Rey, D., Lago, A., & Vilas, F. (Aug 2010). Marine Pollution Bulletin. Vol. 60, no. 8 , 1170-1174.
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