Zebrafish embryo developmental toxicity to a DWH Mousse substrate after prolonged submersion and washout

Does a thin surface layer of DWH Water-in Oil emulsion (Mousse) (as coated substrates in marshes) retain its developmental toxicity to embryos of substrate breeding fish after prolonged submersion and washout. Design: 1) Control unbuttered cups , 3 cups / time interval, 5 sets of 3 control cups; 2) Mousse treatments: Water-in-oil emulsion (250mg) was evenly and thinly buttered on 16 cm2 cup bottoms (3 cups / time interval). Control and treatment cups were separately batch submersed under flowing freshwater (200 ml / min) for 0, 43, 167, 236 and 328 days. After washout intervals a control and treatment set (6 cups , 3 cups each) were gently rinsed with R/O water, emptied, filled with zebrafish embryo media and 20 fertilized zebrafish embryos placed in each cup (60 total for control and 60 for each mousse treatment at each of the 5 time intervals). A total of 600 embryos were used for this study. After 96 hrs of development embryos were assessed for abnormalities and cumulative mortalities were assessed out to 192 hours after appropriate washout interval. Data demonstrated for mousse exposed animals as compared to controls, elevated incidence of abnormalities and mortality after a preceding water rinsing of mousse for protracted periods out to 328 days.