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Title: Multi-level effects of low dose rate ionizing radiation on southern toad, Anaxyrus [Bufo] terrestris

Despite their potential vulnerability to contaminants from exposure at multiple life stages, amphibians are one of the least studied groups of vertebrates in ecotoxicology, and research on radiation effects in amphibians is scarce. We used multiple endpoints to assess the radiosensitivity of the southern toad (Anaxyrus [Bufo] terrestris) during its pre-terrestrial stages of development –embryonic, larval, and metamorphic. Toads were exposed, from several hours after oviposition through metamorphosis (up to 77 days later), to four low dose rates of ¹³⁷Cs at 0.13, 2.4, 21, and 222 mGy d⁻¹, resulting in total doses up to 15.8 Gy. Radiation treatments did not affect hatching success of embryos, larval survival, or the length of the larval period. The individual family variation in hatching success of embryos was larger than the radiation response. In contrast, newly metamorphosed individuals from the higher dose-rate treatments had higher mass and mass/length body indices, a measure which may relate to higher post-metamorphic survival. The increased mass and index at higher dose rates may indicate that the chronic, low dose rate radiation exposures triggered secondary responses. Additionally, the increases in growth were linked to a decrease in DNA damage (as measured by the Comet Assay) in red blood cellsmore » at a dose rate of 21mGy d⁻¹ and a total dose of 1.1 Gy. In conclusion, the complex effects of low dose rates of ionizing radiation may trigger growth and cellular repair mechanisms in amphibian larvae.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [5]
  1. Stockholm Univ. (Sweden); Univ. of Georgia, Aiken, SC (United States)
  2. Univ. of Georgia, Aiken, SC (United States)
  3. Univ. of Georgia, Aiken, SC (United States); Univ. of Kentucky, Lexington, KY (United States)
  4. Univ. of Georgia, Aiken, SC (United States); Inst. of Radiation Protection and Nuclear Safety, Cadarache (France)
  5. ENEA, (Italy)
Publication Date:
OSTI Identifier:
1184848
Grant/Contract Number:
FC09-07SR22506
Type:
Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 10; Journal Issue: 4; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Research Org:
Univ. of Georgia, Aiken, SC (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.