The biological effects of ionising radiation on crustaceans: combining lab and field studies
Student thesis: Doctoral Thesis
Amid a renewal of interest in the use of nuclear power and concern regarding past and potential nuclear incidents, assessing the impacts of radiation on the environment has emerged as an area of international scientific and regulatory concern. At present, the impacts of chronic low-dose radiation on non-human organisms are poorly understood. Crustaceans are internationally important model organisms in the field of radioecology and are of commercial and ecological importance. Consequently, this study aimed to adopt a combined laboratory and field approach to assessing the impacts of radiation on crustaceans. Both marine and freshwater crustaceans were exposed to environmentally relevant doses of beta radiation in the laboratory and a range of endpoints including male fertility, DNA damage and development were monitored. In addition, crustacean samples were collected from contaminated environments at Chernobyl and Fukushima and effects on development, reproduction and genetic diversity were assessed. In the laboratory, significant effects on male fertility and sperm DNA damage of the marine crustacean, Echinogammarus marinus, were recorded at doses of 1 mGy/d, with some evidence for knock-on impacts on female reproduction at lower doses of 0.1 mGy/d. No significant effects on male fertility were recorded in the freshwater crustacean, Gammarus pulex. No significant effects on reproduction, development or genetic diversity of crustaceans Asellus aqauticus and Eriocheir japonica (development only) were recorded at Chernobyl and Fukushima respectively. Laboratory studies suggest effects at dose levels below those proposed for environmental radioprotection, though the population-level consequences of these effects are unclear. Conversely, field studies of crustaceans at both Chernobyl and Fukushima found no significant effects of chronic radiation exposure. Based on these results, laboratory studies may provide overly conservative risk assessments of radiation impacts in the environment. These findings challenge current understanding in radioecology and will aid in assessing the risk posed by radiation to aquatic biota and the management of contaminated environments.
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