Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa

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dc.contributor.advisorJackson, Graham Ellisen_ZA
dc.contributor.advisorWinter,Kevinen_ZA
dc.contributor.authorBenamer, Mustafa Alarabien_ZA
dc.date.accessioned2015-06-29T07:53:03Z
dc.date.available2015-06-29T07:53:03Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe Berg River, Western Cape, South Africa, is an example of a catchment region where human pressures and conservation of natural resources collide. The river receives effluents from two large settlements and several smaller adjacent villages, including that of industrial and extensive agricultural activity. The estuary is one of the largest in South Africa and rated as the third most important conservation zone in the country. In this study, the chemical speciation of heavy metals in the river sediment was determined in order to evaluate the extent of pollution. Chemical speciation using sequential chemical extraction of sediment samples was used to measure the mobility and bioavailability of cadmium (Cd), lead (Pb), arsenic (As), chromium (Cr), nickel (Ni), cobalt (Co), iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn). The metals Cd and Zn were found to be the most mobile and bioavailable. The study also examined the vertical distribution of heavy metals in estuarine sediment cores to evaluate the extent of heavy metal contamination with time and the degree to which heavy metals are influenced by other sedimentological parameters such as grain size, sediment composition and organic matter. Three sediment cores, ranging from 160 to 240 em long, were collected using a mechanical vibrating corer. The vertical distribution of metals in the cores showed that the metal concentration was higher at the top and middle of the cores. Based on the enrichment factor (EF) and anthropogenic factor (AF) values, it is suggested that the sediments of the estuary are not polluted with Co, Mn, Cu, Ni, Zn and Fe but moderately to highly polluted with Pb, As, Cd and Cr. The data reported provide a useful baseline for establishing heavy metal concentrations in the estuary and will be an important consideration in future sediment quality studies. The spatial distribution of the metals was also studied to understand how location is linked to metal concentration. The average concentration of metals in the core sediment increased with increasing distance from the mouth of the river. The adsorption behaviour of the estuary sediment with micro-pollutants has a significant influence on the environmental quality of estuary waters. For this reason, the absorption of Pb, Cr, Cu, Ni, and Zn onto sediment was study. It was found that the sediments of the Berg River estuary have a low potential for absorption of Ni and Zn making these metals more mobile and bioavailable.en_ZA
dc.identifier.apacitationBenamer, M. A. (2014). <i>Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/13167en_ZA
dc.identifier.chicagocitationBenamer, Mustafa Alarabi. <i>"Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 2014. http://hdl.handle.net/11427/13167en_ZA
dc.identifier.citationBenamer, M. 2014. Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Benamer, Mustafa Alarabi AB - The Berg River, Western Cape, South Africa, is an example of a catchment region where human pressures and conservation of natural resources collide. The river receives effluents from two large settlements and several smaller adjacent villages, including that of industrial and extensive agricultural activity. The estuary is one of the largest in South Africa and rated as the third most important conservation zone in the country. In this study, the chemical speciation of heavy metals in the river sediment was determined in order to evaluate the extent of pollution. Chemical speciation using sequential chemical extraction of sediment samples was used to measure the mobility and bioavailability of cadmium (Cd), lead (Pb), arsenic (As), chromium (Cr), nickel (Ni), cobalt (Co), iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn). The metals Cd and Zn were found to be the most mobile and bioavailable. The study also examined the vertical distribution of heavy metals in estuarine sediment cores to evaluate the extent of heavy metal contamination with time and the degree to which heavy metals are influenced by other sedimentological parameters such as grain size, sediment composition and organic matter. Three sediment cores, ranging from 160 to 240 em long, were collected using a mechanical vibrating corer. The vertical distribution of metals in the cores showed that the metal concentration was higher at the top and middle of the cores. Based on the enrichment factor (EF) and anthropogenic factor (AF) values, it is suggested that the sediments of the estuary are not polluted with Co, Mn, Cu, Ni, Zn and Fe but moderately to highly polluted with Pb, As, Cd and Cr. The data reported provide a useful baseline for establishing heavy metal concentrations in the estuary and will be an important consideration in future sediment quality studies. The spatial distribution of the metals was also studied to understand how location is linked to metal concentration. The average concentration of metals in the core sediment increased with increasing distance from the mouth of the river. The adsorption behaviour of the estuary sediment with micro-pollutants has a significant influence on the environmental quality of estuary waters. For this reason, the absorption of Pb, Cr, Cu, Ni, and Zn onto sediment was study. It was found that the sediments of the Berg River estuary have a low potential for absorption of Ni and Zn making these metals more mobile and bioavailable. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa TI - Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa UR - http://hdl.handle.net/11427/13167 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/13167
dc.identifier.vancouvercitationBenamer MA. Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/13167en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleChemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africaen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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