SREL Reprint #3648

Evaluation of DNA damage and stress in wildlife chronically exposed to low-dose, low-dose rate radiation from the Fukushima Dai-ichi Nuclear Power Plant accident

Kelly Cunningham1, Thomas G. Hinton2,3, Jared J. Luxton1, Aryn Bordman1, Kei Okuda4,
Lynn E. Taylor1, Josh Hayes1, Hannah C. Gerke5, Sarah M. Chinn5, Donovan Anderson6,
Mark L. Laudenslager7, Tsugiko Takase3, Yui Nemoto8, Hiroko Ishiniwa3,
James C. Beasley5, and Susan M. Bailey1

1Department of Environmental and Radiological Health Sciences, Colorado State University,
Fort Collins, CO 80523-1618, USA
2Centre for Environmental Radioactivity, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1433 Ås, Norway
3Institute of Environmental Radioactivity, 1 Kanayagawa, Fukushima City, Fukushima 960-1296, Japan
4Faculty of Human Environmental Studies, Hiroshima Shudo University, Hiroshima 731-3195, Japan
5Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources,
University of Georgia, Aiken, SC 29808, USA
6Symbiotic Systems Science and Technology, Fukushima University, Fukushima,
Fukushima City, Kanayagawa 960-1248, Japan
7Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
8Fukushima Prefectural Centre for Environmental Creation, 2-10 Fukasaku, Miharu,
Fukushima 963-7799, Japan

Abstract: The health effects associated with chronic low-dose, low-dose rate (LD-LDR) exposures to environmental radiation are uncertain. All dose-effect studies conducted outside controlled laboratory conditions are challenged by inherent complexities of ecological systems and difficulties quantifying dose to free-ranging organisms in natural environments. Consequently, the effects of chronic LD-LDR radiation exposures on wildlife health remain poorly understood and much debated. Here, samples from wild boar (Sus scrofa leucomystax) and rat snakes (Elaphe spp.) were collected between 2016 and 2018 across a gradient of radiation exposures in Fukushima, Japan. In vivo biomarkers of DNA damage and stress were evaluated as a function of multiple measurements of radiation dose. Specifically, we assessed frequencies of dicentric chromosomes (Telomere-Centromere Fluorescence in situ Hybridization: TC-FISH), telomere length (Telo-FISH, qPCR), and cortisol hormone levels (Enzyme Immunoassay: EIA) in wild boar, and telomere length (qPCR) in snakes. These biological parameters were then correlated to robust calculations of radiation dose rate at the time of capture and plausible upper bound lifetime dose, both of which incorporated internal and external dose. No significant relationships were observed between dicentric chromosome frequencies or telomere length and dose rate at capture or lifetime dose (p value range: 0.20–0.97). Radiation exposure significantly associated only with cortisol, where lower concentrations were associated with higher dose rates (r2 = 0.58; p < 0.0001), a relationship that was likely due to other (unmeasured) factors. Our results suggest that wild boar and snakes chronically exposed to LD-LDR radiation sufficient to prohibit human occupancy were not experiencing significant adverse health effects as assessed by biomarkers of DNA damage and stress.

Keywords: Cortisol, Telomeres, Dicentric chromosomes, Low-dose, Low-dose rate radiation, Fukushima

SREL Reprint #3648

Cunningham, K., T. G. Hinton, J. J. Luxton, A. Bordman, K. Okuda, L. E. Taylor, J. Hayes, H. C. Gerke, S. M. Chinn, D. Anderson, M. L. Laudenslager, T. Takase, Y. Nemoto, H. Ishiniwa, J. C. Beasley, and S. M. Bailey. 2021. Evaluation of DNA damage and stress in wildlife chronically exposed to low-dose, low-dose rate radiation from the Fukushima Dai-ichi Nuclear Power Plant accident. Environment International 155: 106675.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).