Selected molluscs as monitors of metal pollution in coastal marine environments

 

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dc.contributor.advisor Brown, Alec C en_ZA
dc.contributor.author Watling, Helen Ruth en_ZA
dc.date.accessioned 2016-03-21T19:24:12Z
dc.date.available 2016-03-21T19:24:12Z
dc.date.issued 1978 en_ZA
dc.identifier.citation Watling, H. 1978. Selected molluscs as monitors of metal pollution in coastal marine environments. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/18107
dc.description Bibliography: pages 150-163. en_ZA
dc.description.abstract The potential of bivalve molluscs as monitors of metal pollution in South African coastal marine environments has been investigated using the species Crassostrea gigas, Crassostrea margaritacea, Perna perna and Choromytilus meridionalis. Metal concentrations in these and other species living along an unpolluted coast have been determined by atomic absorption spectrometry following chemical oxidation of the biological tissues. Variations in concentrations within a population may depend upon the size or sex of the individual and on the season during which the sample is collected. Metal accumulation by the four study species has been investigated under controlled laboratory conditions for the elements zinc, cadmium, copper, lead, iron, manganese, nickel, cobalt and chromium. Rates of accumulation differ between species and for each element. Some of the factors affecting cadmium uptake have been studied. Rates of accumulation depend greatly upon the form of the cadmium in solution but are also affected by changes in environmental parameters. The accumulation rates of other elements are probably also affected by these factors, not necessarily in the same way. The solution concentrations tested for these accumulation experiments, and also those tested for their effects on the filtering rates of adults or on the development of larvae, are higher than those normally found in polluted areas. This implies that these species are sufficiently tolerant of the presence of metals in their environment to be able to act as monitoring organisms. However, adult oysters and mussels may react to the presence of metals or to the estuarine environment, where fluctuations in water salinity may occur regularly and where effluents may be discharged into the freshwater stream. The mollusc which has closed its valves for either of these reasons may avoid the pollutant. This reaction obviously affects the ability of molluscs to monitor such pollutant inputs. Theoretically, the four study species cannot be used to monitor metal pollution in coastal marine environments quantitatively, as metal accumulation is influenced by too many environmental variables. However, the results from field sampling surveys can be interpreted with greater confidence when the effects of these variables on metal accumulation are known. In practice, a semi-quantitative measure of metal pollution can be achieved. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Zoology en_ZA
dc.title Selected molluscs as monitors of metal pollution in coastal marine environments en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Doctoral en_ZA
dc.type.qualificationname PhD en_ZA
uct.type.filetype Text
uct.type.filetype Image


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