DEVELOPMENTAL TOXICITY OF 3 CARRIER SOLVENTS USING EMBRYOS OF THE GRASS SHRIMP, PALAEMONETES PUGIO

Embryos of the grass shrimp (Palaemonetes pugio) have shown sensitivit y to the water soluble fraction of number 2 fuel oil. To determine the possible use of carrier solvents in grass shrimp bioassays, detailed concentration-response experiments for ethanol (EtOH), dimethylsulfoxi de (DMSO), and acetone were performed and LC50 values were obtained us ing two test methods. The 4-d assay included development prior to the time of hatch through the time of hatch, a critical life stage of thes e embryos. The 12-d assay included development from the tissue cap sta ge embryos (late gastrula) through two days post-hatch. The average 4- d LC50s for EtOH, DMSO, and acetone were 12.07, 22.57, and 6.78 g/L, w hereas the average 12-d LC50s were 3.63, 12.33, and 6.94 g/L, respecti vely. The coefficient of variation for each test was less than 25.2%. Based on concentration-response curves, the maximum allowable limit of EtOH, DMSO, and acetone to be used as a carrier in the grass shrimp e mbryo toxicity studies should be <1, <6, and <4 g/L, respectively.