Treating oil spills with chemical dispersants: Is the cure worse than the ailment?

Jul 05, 2013
Oil and dispersant impact the ability of sea bass to face increased temperature, reduced oxygen availability or to swim against a current. Credit: Nicolas Le Bayon, Ifremer

Treating oil spills at sea with chemical dispersants is detrimental to European sea bass. A new study, to be presented at the Society for Experimental Biology meeting in Valencia on July 6, suggests that although chemical dispersants may reduce problems for surface animals, the increased contamination under the water reduces the ability for fish and other organisms to cope with subsequent environmental challenges.

A team of researchers headed by Prof Guy Claireaux at the University of Brest in France looked for the first time at the effects of chemically dispersed oil on the performance of European seabass to subsequent .

The researchers designed swimming challenge tests in an 'aquatic treadmill', similar to the tests used in human medicine for health diagnosis. They analysed European seabass' maximum swimming performance, hypoxia tolerance and thermal sensitivity as markers for their capabilities to face natural contingencies. They then exposed the fish to untreated oil, chemically dispersed oil or alone for 48 hours. During the following 6 weeks they measured individual growth and then once again analysed the seabass' performance in the swimming challenge tests.

Oil exposure impacted the ability of fish to face increased temperature, reduced oxygen availability or to swim against a current and these effects were further aggravated with the addition of the dispersant. The dispersant alone had no effect on the ability of fish to face the challenge tests.

Prof Claireaux said "An reaching the shore is not good for tourism and organisms living on the coast line. Treating the slick at sea will avoid or reduce these problems affecting surface animals (birds and marine mammals). On the other hand, oil dispersion will increase the contamination of the water column and the organisms that occupy it."

Though applying dispersants at sea may reduce the environmental and economic impacts of an oil spill reaching the shoreline, these results show that the choice of response deployed to deal with a spill involves a trade-off between the effects at the surface and in the water column.

Explore further: NOAA establishes 'tipping points' for sea level rise related flooding

More information: This work will be presented at 14:55 on Saturday 6th July 2013.

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User comments : 6

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Humpty
3.5 / 5 (11) Jul 06, 2013
Yes.... dumping NASTY detergent onto an oil slick, to disperse it through the water, is a great idea. When are we going to get public beheadings for idiot managers?
antialias_physorg
4.4 / 5 (8) Jul 06, 2013
Oh...but it sinks and we don't see it anymore...And what we don't see doesn't exist. I think we played that sort of game as children. Yay!

Doesn't PR and a new coat of paint make everything shiny and new and better and wonderful? Stockholders seem to think so (and those are all that matter to the companies)
ValeriaT
1.4 / 5 (5) Jul 06, 2013
It's an elegant way how to dump a load of organic chemicals not just legally, but in pretty well subsidized way.
Shootist
1.4 / 5 (10) Jul 06, 2013
Oil spills are natural, the detergents are not.
deepsand
3.3 / 5 (7) Jul 08, 2013
Oil spills are natural, the detergents are not.

Really?

When and where did Nature spill 10s to 100s of million gallons of oil?
rwinners
3.4 / 5 (5) Jul 08, 2013
Wow. Another jerky article. If sea bass are affected by a combination of oil and dispersants, how can one possibly limit this negative effect to sea bass? How about their food and the food they provide other members of the good chain?
Face it. We are being poisoned in the name of energy production. There seems no question.

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