Daniel Coughlin

Publications (2)0.92 Total impact

• Chapter: Reproductive Effects from Chronic, Multigenerational, Low Dose Rate Exposures to Radiation

  Thomas G. Hinton, Daniel Coughlin, Yi Yi, Travis Glenn, John Zimbrick
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  ABSTRACT: Relatively few experiments have been conducted on the effects to organisms following long-term exposures to low levels of radiation. Even fewer studies have examined the effects of radiological exposures to multiple generations of organisms. Speculations that damage will accumulate and be greater with each passing generation are plausible. Alternative, opposing views that adaptive response and repair mechanisms will counter the effects, such that damage does not increase with each generation, are equally plausible. Few data exist to support one hypothesis over the other, particularly for chronic, low-level exposures to vertebrate organisms. Our research explored exposures of low-dose irradiation to multiple generations of a model vertebrate organism, Japanese medaka (Oryzias latipes), one of the most widely used fish in comparative mutagenesis and carcinogenesis studies. A unique outdoor irradiation facility allowed us to examine effects to five generations of medaka that were continuously irradiated to different dose rates. The dose rates bracketed the IAEA guideline for acceptable chronic exposures to aquatic wildlife (10 mGy day−1), and thus were a test to see if the guidelines were applicable for multigenerational exposures. The effects on reproductive endpoints that might influence population dynamics were examined. Our intention was to test the hypothesis that multigenerational exposures to low dose rate irradiation are no more damaging, as measured by reproductive characteristics that could potentially impact a population, than damage incurred from exposure to a single generation. The data suggest that total accumulated dose may be more meaningful than dose rate when trying to predict effects to populations of chronically exposed organisms. Such knowledge is needed because chronic exposure to low levels of radiation is a more likely scenario for nuclear workers, and to wildlife exposed to routine releases from nuclear facilities. KeywordsMedaka-Radioecology-Dose-effect relationship-Chronic exposure-Low dose-rate-Reproduction
  10/2011: pages 219-232;
• Source

  Available from: sti.srs.gov

  Article: Radiation dose assessment for the biota of terrestrial ecosystems in the shoreline zone of the Chernobyl nuclear power plant cooling pond.

  Boris Ya Oskolkov, Mikhail D Bondarkov, Sergey P Gaschak, Andrey M Maksimenko, Thomas G Hinton, Daniel Coughlin, G Timothy Jannik, Eduardo B Farfán
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  ABSTRACT: Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. This paper addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90Sr and 137Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to draw down naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.
  Health physics 10/2011; 101(4):349-61. · 0.92 Impact Factor