Cleaning up oil spills can be bad for fish

April 14th, 2009 - 4:56 pm ICT by ANI  

Washington, April 14 (ANI): A new research has shown that chemicals commonly used to clean up oil spills make oil far more toxic to fish, particularly for eggs and young fish.

According to a report by Discovery News, the research was done by Fish toxicologist Professor Peter Hodson of Queen’s University in Kingston, Ontario and colleagues.

Scientists already debate about how best to clean up spills. The new work makes those decisions even more complicated and controversial.

“While you can see the risk on the surface, appreciating risk under the surface is much more difficult,” said Hodson. “You’re trading off one set of risks that are fairly clear for another set of risks that are not so clear,” he added.

Oil and water don’t normally mix. So, when a truck, train, or ship accidentally dumps its cargo into a lake, stream or sea, the oil sits on top of the water and spreads across its surface.

The slick substance then flows with the currents and tides, poisoning the animals it encounters along its way.

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. In some beakers, the scientists added a dispersing agent.

Their analyses showed that dispersants greatly increased the amount of hydrocarbons that could affect fish.

In turn, that extra dose of exposure made the oil 100 times more toxic to the animals.

Toxicity was measured as an elevated enzyme response in the livers of the fish.

Exposure to dispersed oil doesn’t kill a lot of fish. 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,” said Dr Nancy Kinner, co-director of the Coastal Response Research Center at the University of New Hampshire in Durham. “It kind of adds fuel to the discussion,” she added.

Another message of the study is that, when it comes to accidents that involve oil, there are no easy answers and no happy endings. (ANI)

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