Date of Award

2017

Document Type

Open Access Dissertation

Department

Biological Sciences

Sub-Department

College of Arts and Sciences

First Advisor

Timothy A. Mousseau

Abstract

The global demand for nuclear energy grows, and so do the risks of an accidental release of nuclear products into the environment. Therefore, understanding the health and ecological effects of contamination by radionuclides should be of great interest for biomedical specialists and the public. Empirical studies unequivocally show that high doses of ionizing radiation (IR) shift the redox-balance of many biological systems and increase the rates of genetic errors. However, the effects of chronic low doses of radiation vary significantly between tissues and between species. The present dissertation comprises the results of experimental and meta-analytical research of a variety of biological effects of environmental contamination by radioactive isotopes.

In the review part (Chapter 1), I performed a rigorous literature analysis of the environmental consequences of the three most serious nuclear accidents – the Fukushima Daiichi nuclear power plant (NPP) accident in Japan (2011); meltdown at the Chernobyl NPP in 1986; and the explosion at the Mayak plutonium production site (both former USSR) in 1957. The results of the meta-analysis demonstrate significant effects of the low (

In the experimental part of this thesis (Chapter 2&3), I presented the results of several tests, by which I aimed to detect the detrimental genetic effects of low dose IR. I tested for the presence of radiation-induced damage in DNA and related that to radionuclide body burdens and fitness of a model animal. The bank vole was used as a vertebrate model and the wild downy dragonfly as an invertebrate model. Both species were sampled in the Chernobyl Exclusion Zone (CEZ), as it remains significantly contaminated by the biologically effective isotopes: cesium-137 and strontium-90. In the results, I demonstrate that natural variation in comet-visualized DNA damage exceeds the additive effect of damage from ionizing radiation. It was also shown that accounting for morphological co-variates, such as sex and age, and random co-variates, such as sampling period, is important in prediction of genetic damage using the comet assay.

Available for download on Wednesday, December 18, 2019

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