December 24, 2010
When BP’s Deepwater Horizon oil spill spewed millions of gallons of crude into the Gulf of Mexico, one of the most pressing questions was how the environmental disaster would affect the area’s other major industry: fishing, and in particular, the highly prized bluefin tuna.
- A d v e r t i s e m e n t
In the short term, Gulf fishing was crippled, as thousands of square miles were immediately closed. But even after some of these areas reopened, scientists and fishermen alike worried about the long-term effect of contamination on the area’s bountiful aquatic life. Recently, evidence has emerged to suggest that the oil spill may have an impact far beyond the Gulf, threatening one of the world’s most lucrative fishing species.
The controversy surrounds dispersants, the chemical compounds that BP (BP) used to break up the spilled oil. Basically a form of detergent, dispersants make it possible for oil to interact with water, transforming huge oil slicks into microscopic droplets that could seemingly disappear into the Gulf. In theory, at least, this would make it easier for bacteria and weather to further break down the oil, allowing it to dissolve into the environment.
When BP began using dispersants, many environmentalists fretted that the compounds might harm the area’s fragile ecosystem. In response, the U.S. Environmental Protection Agency launched a two-pronged study to measure the toxicity of various dispersants. Their ultimate conclusion was that the eight dispersants tested — including Corexit 9500A, the main compound used in the Gulf — were generally less toxic than crude oil. What’s more, the EPA detected little or no increase in toxicity when dispersants were combined with oil. That is, the action of breaking down an oil slick generally did not add more toxins to the Gulf.