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dc.contributor.supervisorJha, Awadhesh
dc.contributor.authorDallas, Lorna Jane
dc.contributor.otherSchool of Biological and Marine Sciencesen_US
dc.date.accessioned2014-01-02T15:16:17Z
dc.date.available2014-01-02T15:16:17Z
dc.date.issued2013
dc.identifier820457en_US
dc.identifier.urihttp://hdl.handle.net/10026.1/2850
dc.descriptionPublished in part as: Dallas et al. (2012) Radiation Research, 177, 693-716; and Dallas et al. (2013) Mutation Research: Genetic Toxicology & Environmental Mutagenesis, 754, 22-31.en_US
dc.description.abstract

Metals and radionuclides are environmentally relevant contaminants, yet their potential impacts on marine organisms have not been adequately evaluated. This is especially true for exposures of longer duration and/or lower contaminant concentration (i.e. chronic) which are often more representative of real world scenarios. In this context, a suite of biomarkers at different levels of biological organisation were investigated in an ecologically relevant bivalve species, Mytilus galloprovin- cialis after exposure to nickel (a metal), zinc pyrithione (an organometal) and tritiated water (a radionuclide). These contaminants were chosen based on their differing properties, and hence, mechanisms of action. All three contaminants produced genotoxicity (DNA strand breaks, as measured by the comet assay, and induction of micronuclei [MN]). For nickel (> 1800 µg L −1 ) and tritiated water (15 MBq L−1 ), biomarkers at lower levels of biological organisation (i.e. DNA strand breaks, MN, changes in the expression of key stress response genes) were more sensitive than those at higher levels (i.e. clearance rate, attachment, tolerance of anoxia). In particular, exposure to tritiated water for 14 days resulted in DNA damage and molecular alterations without affecting higher level responses. As environmental contaminants could interact with other physical or chemical stressors in a complex environment, further exploration of biological responses revealed modulation by hyperthermia with concomitant changes in the transcriptional ex- pression of key defence genes (hsp70, hsp90, mt20, p53 and rad51). In contrast to nickel and tritiated water, exposure to both 0.2 and 2.0 µM zinc pyrithione caused significant deviation from concurrent controls for every biomarker examined, suggesting that further investigation of the environmental impacts of this contaminant is particularly necessary. Variation in biological responses induced by different contaminants suggests that potential links between levels of organisa- tion should be evaluated on a contaminant-specific basis. The integrated, multiple biomarker approach used in the current study provides a robust methodology for such studies, which could be translated to other ecologically relevant species for proper evaluation of risks to both environmental and human health.

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dc.description.sponsorshipEuropean Regional Development Fund, INTERREG IVA (Grant No. 4059)en_US
dc.language.isoenen_US
dc.publisherUniversity of Plymouthen_US
dc.subjectGenotoxicityen_US
dc.subjectEcotoxicologyen_US
dc.subjectMusselen_US
dc.subjectMytilusen_US
dc.subjectMetalsen_US
dc.subjectRadionuclidesen_US
dc.subjectTritiumen_US
dc.subjectMolecularen_US
dc.subjectChronicen_US
dc.titleAn ecotoxicological assessment of the impacts of chronic exposure to metals and radionuclides on marine mussels: relating genotoxicity to molecular and organism-level effectsen_US
dc.typeThesis
plymouth.versionFull versionen_US
dc.identifier.doihttp://dx.doi.org/10.24382/4176


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