It remains unclear what impact chemical dispersants will have on sea life--and only the massive, uncontrolled experiment being run in the Gulf of Mexico will tell
By David Biello
Is Using Dispersants on the BP Gulf Oil Spill Fighting Pollution with Pollution?
Roughly five million liters of dispersants have now been used to break up the oil spilling into the Gulf of Mexico, making this the largest use of such chemicals in U.S. history.
..Nevertheless, just 20 ppm of COREXIT 9500—or one drop in 2.5 liters of water—inhibits growth of Skeletonema costatum, a Gulf of Mexico diatom, according to toxicology test data presented in the 2005 NRC report. It appears to inhibit the phytoplankton's ability to perform photosynthesis, specifically blocking part of the biochemistry that enables the photosystem II complex, Villalobos says. "Skeletonema seems to fall among the most sensitive ones," he says. "Like many aquatic plants, these are organisms that are resilient, that tend to come back even though you wipe them out in some cases chemically."