COMPARATIVE TOXICITY OF COREXIT(R)-7664 TO THE EARLY-LIFE STAGES OF 4MARINE SPECIES

The toxicity of the oil dispersing agent Corexit(R) 7664 was evaluated using the early life stages of four California marine species: the re d abalone (Haliotis rufescens), the tops-melt (Atherinops affinis), a mysid (Holmesimysis costata), and the giant kelp (Macrocystis pyrifera ). Spiked-exposure, continuous-flow toxicity tests of 48-96 h were per formed in triplicate in closed test chambers. Dispersant concentration s were measured by UV spectrophotometry. In terms of median-effect con centration, the order of test sensitivity was Haliotis > Atherinops > Holmesimysis > Macrocystis. NOEC data also showed Haliotis tests to be the most sensitive, with Macrocystis tests having similar values, fol lowed by Atherinops and Holmesimysis tests, respectively. Toxicity of Corexit(R) 7664 was compared to that of Corexit(R) 9527, and the latte r was found to be more toxic to all four species; interspecific rankin gs were similar for the two agents.