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dc.contributor.advisorFrew, Russell
dc.contributor.authorBabaranti, Oluwuyi Ajani
dc.date.available2019-09-29T21:54:15Z
dc.date.copyright2019
dc.identifier.citationBabaranti, O. A. (2019). Tracing Nutrients and Contaminants in Nearshore Food Web (Thesis, Doctor of Philosophy). University of Otago. Retrieved from http://hdl.handle.net/10523/9639en
dc.identifier.urihttp://hdl.handle.net/10523/9639
dc.description.abstractSewage derived organic matter from domestic and municipal wastewater, promotes enhanced secondary productivity, eutrophication and trace metal contamination, reduction in oxygen levels, and biodiversity. It poses a potential impact on human health, contamination of seafood and water and ecological disturbances in the natural aquatic ecosystem. Thus, this research examined the impact of improvement in treatment and disposal schemes employed by a municipal sewage treatment facility on a previously sewage contaminated coastal marine system. It took a critical look into the influence of the discharged of inadequately treated sewage effluent and the modern improved mitigating efforts put in place to ensure proper treatment and disposal by the municipal wastewater treatment plant on the coastal marine waters. It also investigated the influence of other potential terrestrial organic nutrients and contaminants on the coastal marine waters, the flow of energy and their fate through the natural coastal marine food web. Stable isotope analyses incorporated with mixing models, other independent chemical tracers such as (i.e. faecal sterol, fatty acid and elemental analyses) were utilised to infer change in the sewage derived organic matter dynamics of the coastal marine waters. The detected change was attributed to the modification in wastewater treatment and disposal techniques adopted by the municipal wastewater treatment plant. The differences in the carbon and nitrogen isotope ratios of Mytilus galloprovincialis (sentinel organism) were assessed in a preliminary survey to determine the tissues of choice as indicative tools for long-term ecological-based study aimed at tracing the sources and fate of sewage organic materials in the coastal marine waters. The preliminary survey aided the experimental design of the study. Isotope mass balance mixing models were fitted to quantify the contributions of land-based organic materials as part of the diet constituents to examine the influence of terrigenous materials on observed diet switching changes from sewage-derived nutrient source to marine nutrient source in Mytilus galloprovincialis, a prevalent resident marine bivalve collected at the nearshore marine waters. Biochemical compositions and elemental concentrations (independent tracers) in Mytilus galloprovincialis were analysed and used as independent indicative tools for testing the assumptions obtained from the stable isotope analysis mixing models. The tracers indicated the source of nourishment to the resident organism and provided additional insight into the organic nutrient supply and contaminant dynamics of the coastal marine waters. The independent tracers revealed that the marine particulate organic matter was main source of nourishment to the marine bivalve. The sea lion colony provided a minor contribution of faecal matter to the nearshore marine waters. The chemical tracers affirmed that the improvement in the treatment and disposal methods had a positive impact on the nearshore marine waters. Trace metal levels and human health risk assessment on the nearshore marine bivalve affirmed the safe human consumption of the nearshore marine fisheries.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectIsotope mass balance mixing models
dc.subjectStable isotope
dc.subjectSewage derived organic matter
dc.subjecttrace metal contamination
dc.subjectfaecal sterol
dc.subjectchemical tracers
dc.subjectdomestic and municipal wastewater
dc.subjecthuman health risk assessment
dc.subjectmunicipal wastewater treatment plant
dc.titleTracing Nutrients and Contaminants in Nearshore Food Web
dc.typeThesis
dc.date.updated2019-09-27T22:46:52Z
dc.language.rfc3066en
thesis.degree.disciplineChemistry
thesis.degree.nameDoctor of Philosophy
thesis.degree.grantorUniversity of Otago
thesis.degree.levelDoctoral
otago.openaccessOpen
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