Table 2 presents the predicted LC50 values and 95-percent confidence intervals for UC 54012 25WP. The 24- and 48-hour LC50 values for UC 54012 25WP were 0.99 and 0.26 mg/1. All results were based on the nominal concentrations of 0.10, 0.18, 0.32, 0.56, 1.0, 1.8 and 32 pg/1. The no-effect concentration based on the lack of mortality and abnormal effects was 0.10 pg/1 after 48 hours. The abnormal effects of mortality, quiescence, surfacing, erratic locomotion and/or daphnids lying on the bottom of test vessels were observed in the 0.18, 0.32, 0.56, 1.0, 1.8 and 32 pg/1 test concentrations. Table 3 presents the mortality rate and water quality parameters measured during the test. The dissolved oxygen concentrations ranged between 8.4 and 8.6 mg/1. These values represented 91 and 93-percent saturation at 20oC, respectively, and were considered adequate for testing. The pH values of the treated chambers were consistent with the control and ranged from 8.1 to 8.2.