title: Initial evaluation of developmental malformation as an end point in mixture toxicity hazard assessment for aquatic vertebrates.
abstract: The joint toxic action of three binary mixtures was determined for the embryo malformation endpoint of the aquatic FETAX (frog embryo teratogenesis assay: Xenopus) test system. Osteolathyrogenic compounds and short-chain carboxylic acids, representing separate, distinct modes of action for induction of malformation, were selected for testing in 96-hr, static-renewal tests. Three mixtures were tested for each combination, with each combination being tested on three separate occasions. Using toxic unit analysis, the combination of osteolathyrogens and the combination of carboxylic acids produced strictly additive (concentration addition) rates of malformation, while the combination of an osteolathyrogen and a carboxylic acid was less-than-additive (response addition) for induction of malformation. Therefore, developmental malformation may have value as an endpoint in mixture toxicity hazard assessment.
authors.affiliation: Department of Animal Science, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071.
authors.forename: D A
authors.initials: DA
authors.lastname: Dawson
authors.forename: T S
authors.initials: TS
authors.lastname: Wilke
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000473:pathology*; D000629:Aminopropionitrile / Q000633:toxicity; D000818:Animals; D002087:Butyrates / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000502:physiology; D007538:Isoniazid / Q000633:toxicity; D013723:Teratogens / Q000633:toxicity; D014635:Valproic Acid / Q000633:toxicity; D014714:Vertebrates / Q000502:physiology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014981:Xenopus
chemical_list: D002087:Butyrates; D013723:Teratogens; D014874:Water Pollutants, Chemical; D000629:Aminopropionitrile; D014635:Valproic Acid; D007538:Isoniazid