A Closer Look At Dispersants

In this article, I intend to give the reader a somewhat comprehensive understanding, on what a dispersant is, so they can develop their own opinion on its use.Information on the history of its use, goes as far back as the 1970's. However as time went by such investigations were reduced. Despite this decline, investigations that were done focused on ecological impact. These investigations can be deemed as limited, since they emphasized more on coastal ecosystems, rather than those offshore.

Photo take from NOAA 2016

However when using dispersant, it should be noted that different methods of its application is done. Methods of its application include spraying from vessels, small airplanes and even helicopters. Simply making contact with oil does not cause dispersion; energy has to be used to create motion. Agitation facilitates the mixing of oil and dispersant, breaking up of the oil particles. However too much or too little energy from wave action is not optimal for the breakdown process. It was found that medium energy waves get the job done. Dispersants is one of many methods used to clean up oil spills. Others include allowing the oil to break down naturally and the use of Booms and Skimmers. In the hierarchy of methods used, the dispersant method was the final option.

Photo take from NOAA 2016

One may wonder why it is placed so low. I think it is based on the fact that its toxic nature, with regard to organisms, is not fully understood by anyone. This usually leads to varying opinions. In a previous article of mine, dispersants were described as being “as harmful as dish soap” and there were persons that would disagree with this statement. I also mentioned that the long term effect of dispersants on organisms was unclear. This is so because more attention is always given to its short term effects. There is significant information on the acute effects on fishes by dispersants derived from studies done in the past. One such study looked at the toxic effects on fish, by dispersant, oil, and dispersed oil. Of the three, dispersed oil ranked the most toxic followed by oil then dispersant alone. There is another study that could explain why dispersed oil may be the most toxic. This study indicated that breaking up oil exposes more of its harmful compounds. However the results from the study also showed variation in some cases, for example a particular species of fish was not affected at all by dispersed oil, but was negatively impacted by oil alone. Therefore it can be stated that dispersed oil may be toxic or non toxic based on species susceptibility. Another factor was the type of dispersant used, toxicity varied with dispersants. Corexit 9500A dispersed was found to be more toxic than JD2000 dispersed but less toxic than SPC1000 as it related to fish species tested. 

Photo take from NOAA 2016.     Image showing oil that reached coastline. Dispersant are used to try to prevent this.                              

In summary, my findings showed that while most dispersants were found to be toxic, there was some exceptions. Beside its toxicity con we must also remember its pros. The most important being the protection of our coastal areas with its ecosystems and how it facilitates our human activities (fishing, recreation, swimming).

References

Maya, Hutchins. 2012, “Effects of Oil Spill Dispersants on Marine Organisms.” Environmental Science Program, Appalachian State University, Boone, NC.  Retrieved from

NOAA 2016. “Dispersants: A Guided Tour.” Office of Response and Restoration Retieved from

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