Low Dose Rate Irradiation Facility: initial study on chronic exposures to medaka
T.G. Hinton*, D.P. Coughlin, Yi Yi, L.C. Marsh
Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA
Abstract
Uncertainties associated with the effects from chronic low-level exposures
to radiation prompted us to construct a Low Dose Rate Irradiation Facility
(LoDlF). The facility was designed specifically to test the appropriateness
of the 10 mGy d-1 guideline often espoused as acceptable for
protection of aquatic biota from ionizing radiation. Scientists at the
0.4 ha facility use 40 outdoor mesocosms and 137CS irradiators
of three different source strengths to research the effects of chronic
low-level irradiation at different levels of biological organiza- tion.
A description of the facility is included along with results from a pilot
study in which Japanese medaka (a small fish native to Asia) were chronically
irradiated at the highest dose rate possible within the facility (350
± 150 mGy d-1). Irradiated fish produced fewer eggs
per day (p = 0.03); had a lower percentage of viable eggs (p
= 0.04), and produced a lower percentage of hatchlings (p = 0.05).
Although these data are not surprising based on the relatively high dose
rates, they are important to future work at the LoDlF because they con-
firm the utility of our chosen model organism for detecting population-level
responses, and they illustrate the statistical power achieved from using
replicated mesocosms, in that stat- istical significance was achieved
with few replicates per treatment. Future directions for the LoDlF are
presented, as well as an invitation for interested researchers to participate
in our studies.
Published by Elsevier Ltd.
Keywords: Biota dose; Low dose; Chronic irradiation;
Radiological risks; Dose limit
SREL Reprint #2797
Hinton, T. G., D. P. Coughlin, Y. Yi, and L. C. Marsh. 2004. Low dose rate irradiation facility: initial study on chronic exposures to medaka. Journal of Environmental Radioactivity 74:43-55.
