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A geochemical investigation of the waters and sediments of De Hoop Vlei, Bredasdorp district, South Africa
Bibliography: pages 117-121.
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| Format: | Thesis |
| Language: | English |
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Department of Geological Sciences
2016
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| _version_ | 1867613224622358528 |
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| access_status_str | Open Access |
| author | Lanz, Johann |
| author2 | Willis, James |
| author_browse | Lanz, Johann Willis, James |
| author_facet | Willis, James Lanz, Johann |
| author_sort | Lanz, Johann |
| collection | Thesis |
| description | Bibliography: pages 117-121. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/20190 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:44.899Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Geological Sciences |
| publisherStr | Department of Geological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/20190 A geochemical investigation of the waters and sediments of De Hoop Vlei, Bredasdorp district, South Africa Lanz, Johann Willis, James Fey, Martin V Environmental Geochemistry Bibliography: pages 117-121. De Hoop Vlei is a saline coastal lake situated 53 kilometres north-east of Cape Agulhas in the Western Cape Province of South Africa. It is probably of estuarine origin but is now separated from the sea by mobile sand dunes and, therefore, has no surface outflow. Inflow to the vlei is from a catchment area of approximately 1200 km2 in which intensive grain farming is practised. The vlei is situated within the De. Hoop Nature Reserve and its ecological value, particularly as a breeding ground for water birds, has been recognised in its designation as an international RAMSAR conservation site. Agricultural practices in the catchment have been identified as a potential threat to the ecology of the vlei. The overall objective of this study was to provide a geochemical characterisation of De Hoop Vlei. It focused on identifying the geochemical factors and processes which control the water chemistry of the vlei and attempted to identify any influence of agricultural activities on water quality. This was achieved through a geochemical interpretation of the results obtained from analyses of water and sediment samples collected during the study. Use was also made of Department of Water Affairs and Forestry monitoring data in order to examine long term behaviour of the system, particularly with respect to the effect of evaporative concentration on water composition. Furthermore, chemical equilibrium was modelled, using the geochemical model MINTEQA2, in order to give an indication of processes likely to occur in the water as well as the behaviour of certain possible pollutants in the vlei. Water and sediment core samples, collected during two separate sampling trips, were taken along the entire length of the vlei and some water samples were taken in the catchment. Interstitial waters were obtained by suction from sediment cores. Samples of secondary precipitates, found along the edge of the vlei, were also taken. The following laboratory analyses were performed on water samples: pH, EC, alkalinity, major cations and anions, dissolved P, fluoride, and the trace metals Fe, Mn, Al, Ni, Cu, Zn, and Pb. The following laboratory analyses were performed on sediment samples: pH of wet and dried sediments, organic C content, carbonate content, total elemental concentrations of major and trace elements, mineralogy, clay percentage and extractable P, Zn and K. Scanning electron microscopy and mineralogical analyses were performed on samples of secondary precipitates. 2016-07-04T08:42:00Z 2016-07-04T08:42:00Z 1997 Master Thesis Masters MSc http://hdl.handle.net/11427/20190 eng application/pdf Department of Geological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Environmental Geochemistry Lanz, Johann A geochemical investigation of the waters and sediments of De Hoop Vlei, Bredasdorp district, South Africa |
| thesis_degree_str | Master's |
| title | A geochemical investigation of the waters and sediments of De Hoop
Vlei, Bredasdorp district, South Africa |
| title_full | A geochemical investigation of the waters and sediments of De Hoop
Vlei, Bredasdorp district, South Africa |
| title_fullStr | A geochemical investigation of the waters and sediments of De Hoop
Vlei, Bredasdorp district, South Africa |
| title_full_unstemmed | A geochemical investigation of the waters and sediments of De Hoop
Vlei, Bredasdorp district, South Africa |
| title_short | A geochemical investigation of the waters and sediments of De Hoop
Vlei, Bredasdorp district, South Africa |
| title_sort | geochemical investigation of the waters and sediments of de hoop vlei bredasdorp district south africa |
| topic | Environmental Geochemistry |
| url | http://hdl.handle.net/11427/20190 |
| work_keys_str_mv | AT lanzjohann ageochemicalinvestigationofthewatersandsedimentsofdehoopvleibredasdorpdistrictsouthafrica AT lanzjohann geochemicalinvestigationofthewatersandsedimentsofdehoopvleibredasdorpdistrictsouthafrica |