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Title: Methods of detecting genotoxic exposure in the aquatic environment
Author: Lyons, B. P.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 1998
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The aquatic environment contains a variety of natural and anthropogenic compounds capable of interacting with the genetic material of exposed organisms. The 32P-postlabelling assay for the detection of DNA adducts and the micronucleus assay offer considerable potential for the qualitative and quantitative assessment of genotoxin exposure. This work describes several studies in which the two techniques were adapted for evaluation of genotoxin exposure in the benthic teleosts dab, Limanda limanda, turbot, Scophthalmus maximus, the intertidal teleost shanny, Lipophrys pholis and the bivalve mollusc, Mytilus edulis. Studies detailing the detection of DNA adducts in feral fish samples showed the suitability of the 32P-postlabelling assay for monitoring exposure to genotoxins. Sampling of L. limanda from sites of contrasting contamination demonstrated the detection of DNA adducts may be related to the levels of sediment-bound contaminants. These findings were further supported by the detection of elevated levels of adducts in L. pholis and M. edulis collected from oil exposed shores following the Sea Empress incident. A series of mesocosm experiments were conducted with L. limanda and S. maximus which confirmed adduct induction by exposure to mixtures of polycyclic aromatic hydrocarbons. The suitability of the micronucleus assay for aquatic monitoring remains to be determined. No statistically significant elevations of micronuclei were detected in the peripheral erythrocytes of S. maximus following treatment with contaminated sediment extracts. In contrast, elevated frequencies of micronuclei were detected in the haemocytes of M. edulis collected from oil exposed shores following the Sea Empress incident. These studies suggest that the determination of micronuclei may not be universally applicable as a biomarker of genotoxin contamination in the aquatic environment. Finally, as a step in the development of methods for detecting point mutations in aquatic species, a number of gene sequences were characterised.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available