As boaters, we know that when there is a spill of fuel at the fueling docks/marina, we are not allowed to use dispersants. The Coast Guard should be called. We know that using dispersants (like, for example, Dawn dishwashing liquid) only further hinders the cleanup by making the pollutants sink. Why then did Coast Guard Adm. Thad Allen allow the widespread use of chemical dispersants in the gulf? We have all seen the ugly pictures of the well-dispersed oil in the water. This has got to be more impactful on the sea life than if they had just skimmed it off the top.
We turned to Edward Van Vleet, University of South Florida College of Marine Science director of academic affairs, for help with this one. He writes:
"The reader is absolutely right about the use (or non-use) of chemical dispersants. Most states prohibit the use of dispersants near shorelines and coastal areas. Dispersants have been used primarily to combat oil spills offshore.
"Nonetheless, the use of dispersants offshore is also controversial. The chemical composition of the dispersant allows the oil to be transported away from the surface and deeper into the water. However, dispersants do not alter the toxicity of the oil at all; they just move the oil into a different place. Just because the oil is out of sight does not make it less dangerous to the marine life (in fact, in some cases the dispersant can even increase the toxicity).
"Removing the oil from the surface normally prevents it from later washing ashore and fouling beaches. This is good for the beaches, the wetlands, the mangroves, the tourists, the coastal economies and for marine life that feeds or lives part of the time at the sea surface (such as sea turtles, marine mammals and sea birds). However, after the oil sinks below the surface, it simply becomes available to other marine organisms living deeper in the water column, and hence affects a much broader range of marine life (including fish, plankton, corals, etc.).
"So, indeed the use of dispersants is controversial, and at the very least is a trade-off of which ecosystems to affect."
Another source of good information is a story written by Craig Pittman of the Times on June 25, which contained this statement from EPA administrator Lisa Jackson: Her agency will continue allowing dispersant use because "dispersants are one tool in a situation that could not be more urgent" - even though, she acknowledged, "We know that they come with environmental trade-offs."
You can read that full story here: www.tampabay.com/news/environment/water/article1104771.ece.
Another story on-point is this one, also by Pittman: www.tampabay.com/news/environment/water/fisherman-question-use-of-chemical-dispersants-in-gulf-oil-spill/1094257.