| Abstract: | Fish and Amphibian Embryos—A Model System for EvaluatingTeratogenicity. Birge, W.J., Black, J.A., Westerman, A.G. andRamey, B.A. (1983). Fundam. Appl. Toxicol. 3: 237–242.Developmental stages of fish and amphibians were used to evaluatereproductive impairments produced by environmental contaminants.Using static-renewal and flow-through procedures, exposure wasinitiated at, or soon after, fertilization and maintained through4 days posthatching. Trace concentrations of many environmentaltoxicants produced high frequencies of mortality and teratogenesis.When developmental stages of the trout were exposed to inorganicmercury, 10% control-adjusted mortality was observed at 1 µg/Land frequencies of terata in hatched populations ranged from8% to 43% for exposure concentrations of 2 to 25 µg/L-In similar tests with the narrow-mouthed toad, 45% mortalityoccurred when mercury was administered at 1 µg/L; frequenciesof teratogenesis ranged from 8% to 17% at exposure concentrationsof 1 to 5 µg/L; and complete mortality occurred at 7 µg/L.Boron-induced teratogenesis in trout ranged from 5% at 1 µg/Lto 51% at higher exposure levels. When catfish embryos wereexposed to atrazine at 0.06, 4.8, and 46.7 mg/L, terata appearedin surviving populations at frequencies of 4%, 69%, and 100%,respectively. Fish and amphibian developmental stages constitutesimple and effective models for 1) investigating mechanismsof teratogenesis, 2) evaluating the impact of environmentaltoxicants on aquatic biota, and 3) identifying environmentalteratogens which may be of concern to human health. |
