Oil Spill Clean-up Agents Threaten Coral Reefs

Daily Science Journal (Jul. 31, 2007) — In a setback for efforts to protect endangered coral reefs from oil spills, researchers in Israel report that oil dispersants -- the best tool for treating oil spills in tropical areas --are significantly more toxic to coral than the oil they are used to clean up. Their study, which urges caution in the use of these materials, is scheduled for the August 1 issue of ACS' Environmental Science & Technology.

Oil-spill clean-up agents are a threat to coral reefs, researchers say. Credit: (Credit: Courtesy of Shai Shafir, The Hebrew University of Jerusalem)

Called the 'rainforests of the sea,' coral reefs are an endangered ecosystem and are disappearing at an alarming rate due to numerous threats, including over-fishing, global warming and pollution, particularly oil spills. Besides hosting a rich diversity of marine organisms, these habitats are also potential sources of life-saving medicines and food for humans. Scientists looking for better ways to protect this important habitat have recently focused on the environmental impact of oil dispersants, detergents used break down oil spills into smaller, less harmful droplets.

In the new report, Shai Shafir and colleagues evaluated the effects of both crude oil and six commercial oil dispersants under laboratory conditions on the growth and survival of two important species of reef corals. The dispersants and dispersed oil droplets were significantly more toxic to the coral than the crude oil itself, the scientists report. The dispersants caused "significant harm," including rapid, widespread death and delay in growth rates, to the coral colonies tested even at doses recommended by the manufacturers, they add.

"Decision-making authorities should carefully consider these results when evaluating possible use of oil dispersants as a mitigation tool against oil pollution near coral reef areas," the report said.

Article: "Short and Long Term Toxicity of Crude Oil and Oil Dispersants to Two Representative Coral Species"

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.