An evaluation of the aquatic hazard of cumene (isopropyl benzene).

Cumene manufacturers were required under a TSCA Section 4(a) test rule to evaluate the aquatic toxicity of cumene to daphnids, rainbow trout, mysid shrimp, and sheepshead minnows. Because of cumene's high volatility (vapor pressure, 3.2 mm Hg at 20 degrees C), all tests were conducted under flowthrough conditions using a proportional diluter system. The 96-hr LC50s for rainbow trout, sheepshead minnow, and mysid shrimp, based on mean measured concentrations, were 4.8, 4.7, and 1.3 mg/liter, respectively. The 48-hr daphnid EC50 was 4.0 mg/liter. Although cumene is considered moderately toxic to aquatic organisms under rigorous laboratory conditions, its volatility and biodegradability greatly reduce its hazard to the aquatic environment.