ASSESSING THE DISTRIBUTION OF SEDIMENTARY HEAVY METALS IN THE MSUNDUZI RIVER CATCHMENT, KWAZULU- NATAL, SOUTH AFRICA by Mendy Shozi MSc Submitted in fulfilment of the academic requirements for the degree of Master of Science in Environmental Sciences, in the School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Durban, South Africa. February 2015 NOTE: This thesis has been prepared according to Format 3 as outlined in the guidelines from the College of Agriculture, Engineering and Science which states: This is a thesis in which the chapters are written as a set of discrete research papers, with an Overall Introduction and a Final Conclusion. These research papers would not be published yet. The references are reformatted to a uniform standard. As the candidate’s supervisors, we have approved this thesis for submission. Signed: Name: Dr J. Finch Date: Signed: Name: Dr L. Pillay Date: ABSTRACT Heavy metal pollution of freshwater environments is a global and local crisis due to the toxic nature of metals. Elevated concentrations of heavy metals in sediments, in comparison to sediment quality guidelines (SQGs), are an indication of anthropogenic input into the environment. Concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) were investigated in the water and sediments of Msunduzi River and two of its tributaries, the Bayne’s Spruit and Slangspruit, in KwaZulu-Natal, South Africa. Macro-elements, aluminium (Al), iron (Fe) and manganese (Mn) were also investigated and compared to the distribution and partitioning pattern of the trace metal concentrations. Total metal concentrations in the water samples were below the detection limit of the Inductively Coupled Plasma– Optical Emission Spectrometry (ICP-OES) for most metals. In surface sediments, total metal concentrations were >Effects Range-Low (ERL) of the SQG. The Community Bureau of Reference (BCR) sequential extraction protocol was used to determine speciation of metals in the sediments and implications for potential bioavailability and overall metal toxicity. Results indicated that potentially mobile sediment fraction concentrations were >ERL for most of the metals. Fe-Mn oxyhydroxides, organic matter content and redox potential had an effect on the geochemical partitioning and possible remobilisation or precipitation of the metals in all three rivers. Negative redox values were indicative of reducing conditions that remobilised metals from the sediments. In the sediment core, the trace metals had the same deposition pattern and were correlated to organic matter content at depth. Normalisation with Al, at 95% confidence interval indicated that the sediment in the Msunduzi River Catchment is enriched with anthropogenic heavy metal input. In terms of particle size distribution in the sediment core, the sediment was mainly made up of fine sediment (≤500 µm). The sediment is a potential source of long-term heavy metal pollution in the catchment. ii PREFACE The experimental work described in this thesis was carried out in the School of Chemistry and Physics, University of KwaZulu-Natal, Durban, from February 2012 to January 2015, under the supervision of Dr J. Finch and Dr L. Pillay. These studies represent original work by the author and have not otherwise been submitted in any form for any degree or diploma to any tertiary institution. Where use has been made of the work of others it is duly acknowledged in the text. Mendy Shozi iii DECLARATION 1 Plagiarism I, Mendy Shozi, declare that 1. The research reported in this thesis, except where otherwise indicated, is my original research. 2. This thesis has not been submitted for any degree or examination at any other university. 3. This thesis does not contain other persons’ data, pictures, graphs or other information, unless specifically acknowledged as being sourced from other persons. 4. This thesis does not contain other persons' writing, unless specifically acknowledged as being sourced from other researchers. Where other written sources have been quoted, then: a. Their words have been re-written but the general information attributed to them has been referenced b. Where their exact words have been used, then their writing has been placed in italics and inside quotation marks, and referenced. 5. This thesis does not contain text, graphics or tables copied and pasted from the Internet, unless specifically acknowledged, and the source being detailed in the thesis and in the References sections. Mendy Shozi iv DECLARATION 2 Publications and conference contributions DETAILS OF CONTRIBUTION TO PUBLICATIONS that form part and/or include research presented in this thesis (include publications in preparation, submitted, in press and published and give details of the contributions of each author to the experimental work and writing of each publication). Conference contributions 1. Poster presentation, Assessing the distribution of sedimentary heavy metals in the Msunduzi River Catchment, KwaZulu-Natal, South Africa, College of Agriculture, Engineering and Science Research Day, Howard College, Durban, South Africa, 2013 2. Poster presentation, Assessing the distribution of sedimentary heavy metals in the Msunduzi River Catchment, KwaZulu-Natal, South Africa,9th Biennial SSAG Conference, Bloemfontein, South Africa, 2013 3. Oral presentation, Assessing the distribution of sedimentary heavy metals in the Msunduzi River Catchment, KwaZulu-Natal, South Africa,10th Biennial SSAG Conference, East London, South Africa, 2014 4. Oral presentation, Assessing the distribution of sedimentary heavy metals in the Msunduzi River Catchment, KwaZulu-Natal, South Africa, SAEON GSN Indibano, Port Elizabeth, South Africa, 2014 ________________ Mendy Shozi v ACKNOWLEDGMENT First and foremost I would like to thank God for affording me the opportunity to pursue my studies. The following people played an important role in the completion of my thesis: My supervisor, Dr Jemma Finch and co-supervisor Dr Letitia Pillay, for their time, patience, guidance and support throughout my studies. My Family and Friends, particularly my mother, for their continued support and countless advice. The University of KwaZulu-Natal, College of Agriculture, Engineering and Science and the National Research Foundation (Masters Innovation Bursary Scheme) for financial support. The University of KwaZulu-Natal School of Chemistry and Physics and School of Agricultural, Earth and Environmental Sciences for technical support. The Council for Scientific and Industrial Research (CSIR) – Consulting and Analytical Services unit for extended technical support. A special thank you to Professor T. Hill, Kate Strachan and Luke Bodmann for field assistance. A special thank you to Luanita van der Walt and Abulele Adams from the CSIR for technical GIS assistance in producing the maps. Pat Morant and Dr Brent Newman from the CSIR for lending their time, academic expertise and advice. vi TABLE OF CONTENTS Abstract ................................................................................................................................................... ii Preface .................................................................................................................................................... iii Declaration 1 .......................................................................................................................................... iv Declaration 2 ........................................................................................................................................... v Acknowledgment ................................................................................................................................... vi Table of Contents .................................................................................................................................. vii List of Figures ........................................................................................................................................ ix List of Tables ........................................................................................................................................... x List of Appendices ................................................................................................................................. xi List of Abbreviations and Units .......................................................................................................... xii 1 Introduction ................................................................................................................................... 1 1.1 AIM AND OBJECTIVES ....................................................................................................................... 4 1.2 REFERENCES ................................................................................................................................... 5 2 Literature review ........................................................................................................................ 11 2.1 HEAVY METALS ............................................................................................................................. 11 2.2 TOTAL METALS .............................................................................................................................. 11 2.2.1 Trace metals ..................................................................................................................