One More Reason Oil Spills Are Bad: Surface Cleanup can Make it Worse for Fish Below


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Out of Sight, Out of Mind, Right?
A study published in Environmental Toxicology and Chemistry points to something pretty shocking: One of the usual methods of cleaning up an oil spill can help save birds and marine animals on the surface of the water, but it makes things worse for life below. The culprits are chemical dispersing agents that are used to make the oil "bead up into tiny droplets that can mix into the water and disperse into deeper layers. Underwater currents can then theoretically dilute the oil and its risk to the environment." But while these detergent-based chemicals might look like they make a big difference to use, looking at the scene from above the water, they can apparently cause lots of harm to fish.

From Discovery News:

Dispersion spares surface-dwelling animals, such as birds and otters. But as oil drifts downward, it falls on fish and on the eggs that are stuck to surfaces or buried in the sediment.

To find out just how dangerous dispersed oil might be to fish, Hodson and colleagues performed a series of laboratory experiments with beakers that were meant to simulate contaminated lakes. In all of the beakers, the scientists mixed water with diesel oil, then added newly hatched trout embryos. In some beakers, the scientists added a dispersing agent. [...]

Exposure to dispersed oil doesn't kill a lot of fish, Hodson added. Instead, it either kills eggs before they hatch or leads to damage or deformities in juvenile fish. Compared to the horrifying appearance of oil-drenched birds on beaches, it can be hard to catch the attention of the public -- or even of cleanup managers -- with such subtle and hidden health effects.

"What he's saying, and he's correct, is that it could be way more fish fingerlings or eggs that are impacted than you'd ever impact birds," Kinner said. "It kind of adds fuel to the discussion."

As the Exxon Valdez spill's anniversary reminded us recently, the only real solution is to avoid these oil spills altogether. It's outrageous that "even after 79 percent of the world supertanker fleet has been replaced by craft with two hulls, Exxon Mobil Corp. remains the biggest Western user of the older designs. It hired more of the tankers last year than the rest of the 10 biggest companies by market value combined, according to data compiled by Bloomberg."

Via Discovery News
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Tags: Animals | Oceans | Pollution