The purpose of this study was to estimate the acute toxicity (EC50) of (confidential) to daphnids (Dephnia magna) under static test conditions. The EC50 is defined as the concentration of the test substance in dilution water which causes immobilization of 50% in the exposed test population after a fixed period of time. This value is often used as a relative indicator of potential acute hazards resulting from release of the test substance into aquatic environments. The study was initiated on 4 January 1996, the day the Study Director signed the protocol, and was completed on the day the Study Director signed the final report. The experimental phase of the 48-hour definitive test was conducted from 2 to 4 May 1996 at Springbom Laboratories, Inc. (SU), Health and Environmental Sciences, located in Wareham, Massachusetts. All original raw data and the final report produced during this study are stored in Springbom's archives at the above location.