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What are chemical dispersants?
Just putting the word chemical in a description does not make it a bad thing. Many safe and natural chemicals are used in a range of our everyday activities. Chemical dispersants are surface active agents (commonly called "surfactants") and are produced from both natural (renewable) sources as well as petrochemical ingredients.
How Dispersants Work?
Dispersants do not remove oil from a spill area, instead they help large continuous layers of oil to break down into smaller droplets. They work along the same lines as kitchen detergents or hand soap. Both are made up mostly of surfactant ingredients which have an oil soluble end and a water soluble end. The oil soluble end is attracted to the oil while the water soluble end remains in the water phase. Lowering the interfacial tension reduces the energy required to mix the oil as discrete droplets into the water phase. Dispersing the oil into smaller droplets allows naturally occurring microbes to metabolize the oil into harmless by products.
Dispersants have been studied by a number of agencies. A 1999 International Oil Spill Conference Report presented by the National Environmental Technology Centre, AEA Technology Environment in the United Kingdom reported on the effect of dispersants on oil biodegradation under simulated marine conditions. This report concludes the application of the four tested dispersants (including Nalco Corexit 9500) to an oil slick in mesocosms simulated oil dispersion and oil biodegradation even at a low nutrient concentration. The report indicates that hydrocarbon degrading organisms performed better in dispersant treated oil dispersions than in mechanical oil dispersions. The positive effect of the tested dispersants on oil biodegradation seems to be related to their ability to promote the growth of indigenous hydrocarbon-degrading bacteria, as well as their ability to form small droplets.
How does oil react with increased bio activity?
In the above mentioned report it was noted the naturally occurring microbes colonised the dispersed droplets and caused many to agglomerate (form larger droplets) into neutrally-buoyant clusters, which became small micro-habitats where bacteria were degrading oil and where they were decomposed by protozoal and nematode predators. These clusters remained suspended in the water column of the microcosms until much of the biodegradable residues of oil had been decomposed before sinking to the bottom of the microcosms.
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Cytosol Product Information
Chemical Dispersants
