Effects of depleted uranium on survival, growth, and metamorphosis in the African clawed frog (Xenopus laevis).
Embryos (stage 8-47, Nieuwkoop and Faber) of the African clawed frog (Xenopus laevis) were subjected to water-borne depleted uranium (DU) concentrations that ranged from 4.8 to 77.7 mg/L using an acute 96-h frog embryo teratogenesis assay-Xenopus (FETAX). In a chronic 64-d assay, X. laevis (from embryo through metamorphosis; stages 8-66) were subjected to concentrations of DU that ranged from 6.2 to 54.3 mg/L. Our results indicate DU is a non teratogenic metal. No effects on mortality, malformations, or growth were observed in the 96-h FETAX with concentrations of DU that ranged from 4.8 to 77.7 mg/L. From stage 8 to stage 47, X. laevis tadpoles do not actively feed and the gills are not well developed. Thus, uptake of DU was reduced despite exposure to elevated concentrations. The 64-d assay resulted in no concentration response for either mortality or malformations; however, a delay in metamorphosis was observed in tadpoles subjected to elevated DU concentrations (from 13.1 to 54.3 mg/L) compared to tadpoles in both the well-water control and reference. The delay in metamorphosis was likely due to increasing body burden of DU that ranged from 0.98 to 2.82 mg/kg.
Mitchell
Sarah E
SE
University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, Mississippi, USA. Sarah.mitchell@usm.edu
Caldwell
Colleen A
CA
Gonzales
Gil
G
Gould
William R
WR
Arimoto
Richard
R
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects; D008675:Metamorphosis, Biological / Q000187:drug effects*; D013723:Teratogens / Q000633:toxicity; D014501:Uranium / Q000633:toxicity*; D014875:Water Pollutants, Radioactive / Q000633:toxicity*; D014982:Xenopus laevis / Q000196:embryology / Q000254:growth & development
D013723:Teratogens; D014875:Water Pollutants, Radioactive; D014501:Uranium