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WP9 Endocrine Disruption: Fish Estrogenicity
(473) Effects of ammonium perchlorate, 4-(tert octyl) phenol, and their mixture on zebrafish (Danio rerio).
Cruz-Li, E.1, La Point, T.2, Patino, R.1, Cobb, G.1, 1 Texas Tech University, Lubbock;, TX, USA2 University of North Texas, Denton, TX, USA
ABSTRACT- The toxic and developmental effects of ammonium perchlorate (AP) and 4-(tert-octyl) phenol (OP) on zebrafish (Danio rerio) embryos and larvae were examined. AP inhibits thyroid function and OP is a weak xenoestrogen. Because reproduction and development occur under precise physiological regulation, use of these chemicals during the perihatch period helps to understand effects on biological processes and the ecological significance posed by the exposure to contaminant mixtures. Fertilized eggs were collected from unexposed (control) parents and exposed to sublethal nominal concentrations of AP (8 X 10-8 M), OP (1 X 10-8 M) or their mixture starting at 12 hours post fertilization. Embryo/larval exposures occurred at three different periods: 0 to 6 days (embryo-larval), 0 to 3 days (embryo), and 3 to 6 days (larval) after fertilization. Hatching, mortality, and gross abnormalities were determined daily through day 20; and predator escape behavior was assessed on Days 6, 15 and 30. Control mortalities were 4 (6 days), 55.1 (20 days), and 55.6 % (30 days). OP treatment of embryos had mortalities of 9.9, 84.9, and 85.3 %; larval mortality was 5.3, 75.3, and 77.3 %; and embryo-larvae mortality was 18.6, 76.9, and 78 % on days 6, 20, and 30, respectively. AP treatment of embryos yielded mortalities of 3.6, 83.7, and 84.4 %; larval mortality was 15.9, 82.1, and 82.1 %; and embryo-larval mortality was 18.5, 60.6, and 63.8 % on days 6, 20, and 30, respectively. The mixture treatment of embryos yielded mortalities of 10.5, 80.9, 83.3 %; larval mortality was 2.8, 72.9, and 75 %; and the embryo-larval mortality was 10, 92.2, and 93.3 % on days 6, 20, and 30, respectively. Ongoing analysis will provide information on predator escape behavior and reproductive endpoints. Reproductive success (volume of eggs spawned) will be assessed for fish that survive to Day 180.
Key words: 4-(tert octyl) phenol, perchlorate, zebrafish, chemical mixture
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