Ecological Integrity of Westdene and Emmarentia Dams in Johannesburg
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COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. How to cite this thesis Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujdigispace.uj.ac.za (Accessed: Date). ECOLOGICAL INTEGRITY OF WESTDENE AND EMMARENTIA DAMS IN JOHANNESBURG By LERATO MASETLE Mini dissertation submitted in partial fulfillment for the degree Masters In Science (Z O O) in Aquatic Health (Zoology) in the Faculty of Science UNIVERSITY OF JOHANNESBURG Supervisor: Prof. Victor Wepener October 2013 i DECLARATION I declare that this dissertation is my unaided work being submitted for the degree of Masters of Science in the University of the Johannesburg, Auckland Park. It has not been submitted elsewhere for any degree or examination. I have acknowledged all the sources of information which have been used in the dissertation. Signature ________________________________________ Date _____________ Day of _________________________, 2013 ii ACKNOWLEDGEMENTS Special thanks and appreciation to the following persons and organizations: The University of Johannesburg for allowing me to do this study and for the use of all equipment and facilities necessary for the project. My supervisor, Prof Victor. Wepener for his professional assistance, guidance and intellectual support throughout the project. Dr. Richard Greenfield, Dr. Martin Ferreira, and Mr. Wynand Malherbe for their assistance with field work. Mr. Mkhacani Moses Mathonsi for his assistance in the aquarium. My family for their ever willing support and guidance, particularly my mother for her support and fine words of encouragement throughout this project. Praise and glory to my Creator without whom my existence and all that it entails would not have been possible. iii A BST R A C T Urban impoundments play both a recreational and functional role in the urban areas. From the recreational point of view these impoundments offer aesthetically pleasing environs as well as habitat for aquatic organisms in a built environment. The functional role of impoundments is related to attenuation of storm water run-off that is released into urban water courses. Storm water run-off can have adverse effects on the ecological integrity of aquatic ecosystems. Water quality will influence other physical and biological components of these systems. It is for this reason that the ecological health of impoundments is assessed from an ecotoxicological perspective, focusing on Westdene and Emmarentia dams in Johannesburg. It has become common practice to use aquatic biota to assess the impacts of human activities on aquatic ecosystems. This is because animals and plants can provide a long-term integrated reflection of water quality, quantity, habitat quality and other environmental conditions. Water and sediment quality were assessed by applying standard techniques and protocols. Fish were utilized as bioindicator organisms in order to quantify the concentrations of metals available in the dam. Abundance of the macro invertebrate community was also measured. Physico-chemical water analyses were done during each sampling period to assess the water quality against the South African Water Quality Guidelines. Ammonia, which can be toxic to aquatic life, remained high in both dams. High phosphate concentration during the low rainfall season in Westdene Dam could result in eutrophication related problems. The microbiological analysis of the water suggests that the main cause of faecal and total coliforms contamination of the impoundments possibly originates from dominant birds, African Sacred Ibis (Threskiornis iv aethiopicus) and Egyptian Goose (Alopochen aegyptiaca) in the dam and others water birds frequenting the dams. Abnormally high concentrations of the heavy metals Nickel and Chromium were found in the water body and fish (Clarias gariepinus and Tilapia sparmanii) thus indicating bioavailabity of these metals resulting in bioaccumulation in fish. High concentration of Lead in sediment was recorded and may greatly impact benthic macroinvertebrates population and their habitat. v TABLE OF CONTENTS Declaration ii Acknowledgements iii Abstract iv Table of contents vi List of tables viii List of figures ix CHAPTER 1: INTRODUCTION 1.1 Urban impoundments 1 1.2 Aquatic Health Assessment 2 1.3 Physico-chemical and microbiological water quality properties 2 1.4 Physico-chemical properties of sediment 4 1.5 Metal contamination in run-off from urban areas 5 1.6 Impact of heavy metals on organisms 7 1.7 Organisms impacted by pollution 8 1.8 Metal bioaccumulation in fish 8 1.9 Metal bioaccumulation in feathers 9 Rationale 10 Aim & Objectives 11 C H APT E R 2: MATERIALS AND METHODS 2.1 Field site descriptions 12 2.2 Sampling protocol 15 vi 2.3 Laboratory work/ procedures 15 2.4 Water quality 15 2.5 Microbiological water quality 16 2.6 Physical and chemical properties of sediment 16 2.7 Metal bioaccumulation in fish 18 2.8 Metal bioaccumulation in bird feathers 18 2.9 Macroinvertebrates 19 2.10 Statistical Analyses 19 C H APT E R 3: R ESU L TS 3.1 Water quality 21 3.2 Microbiological water quality analyses 26 3.3 Level of trace metals in water 30 3.4 Metal concentration in sediment 34 3.5 Physical and chemical properties of sediments 37 3.6 Metal concentrations in various fish tissues 39 3.7 Metal concentration in various bird feathers 42 3.8 Macroinvertebrates 43 C H APT E R 4: Discussion 47 Conclusion 54 REFERENCES 56 vii LIST OF TABLES Table1 Classification of organic matter (OM) content in sediment (USEPA, 1991). Table 2 The classification used for the sediment grain size analysis (Cyrus et al., 2000). Table 3 Mean ± and standard error of water quality parameters measured at three sites in Westdene Dam during the high rainfall sampling period. Table 4 Mean ± and standard error of water quality parameters measured at three sites in Westdene Dam during the low rainfall sampling period. Table 5 Mean ± standard error of water quality parameters measured at three sites in Emmarentia Dam during the low rainfall sampling period. Table 6 Physical and chemical characteristics of sediment collected during low rainfall in Westdene and Emmarentia Dams. Table 7 Physical and chemical characteristics of sediment collected during high rainfall in Westdene Dam. Table 8 Abundance of macroinvertebrates at different sites along the Emmarentia and Westdene Dam. LIST OF FIGURES Figure1 Study area in Gauteng, South Africa showing headwaters of the Limpopo rising on the Witwatersrand ridge as the Braamfontein Spruit near the Emmarentia and Westdene dams. (Google Earth Images 2013 Digital Globe) Figure 2 Total and faecal coliform counts in Westdene Dam during the high and low rainfall sampling period. viii Figure 3 Total and faecal coliform counts in Emmarentia Dam during the low rainfall sampling period. Figure 4 Faecal coliform counts in Emmarentia and Westdene Dam during the low rainfall sampling period. Figure 5 Dissolved metal concentration at Emmarentia and Westdene Dam during the high and low rainfall sampling period. Figure 6 Dissolved metal concentrations at three sites in Westdene Dam during the high and low rainfall sampling period. Figure 7 Dissolved metal concentrations at three sites in Emmarentia Dam during the low rainfall sampling period. Figure 8 PCA plot showing the dissimilarity among sites in Emmarentia and Westdene Dam during high and low flow regimes based on the water quality characteristics. Figure 9 Sediment metal concentrations in Westdene Dam during the high and low rainfall sampling period. Figure 10 Sediment metal concentrations in Emmarentia Dam during the low rainfall sampling period. Figure 11 PCA plots showing dissimilarity among sites in Emmarentia and Westdene Dam during high and low flow regimes based on sediment characteristics. Figure 12 Dissolved metal concentrations for the two whole fish species at Westdene and Emmarentia Dam during the low rainfall sampling period. Figure 13 Metal concentrations of various tissues in Banded Tilapia (Tilapia sparmanii) in Westdene dam during high rainfall. ix Figure 14 Metal concentrations of various tissues in Sharptooth Catfish (Clarias gariepinus) in Westdene dam during high rainfall. Figure 15 Metal concentrations in feathers of Egyptian geese (Alopochen aegyptiaca) and Sacred ibis (Threskionis aethiopicus) in Emmarentia dam during the low rainfall sampling period. Figure 16 Metal concentrations in feathers of Egyptian geese (Alopochen aegyptiaca) and Sacred ibis (Threskionis aethiopicus) in Westdene Dam during the low rainfall sampling period. Figure 17 RDA plot showing dissimilarity among sites in Emmarentia and Westdene Dam during with and low flow regimes based on invertebrate communities. x CHAPTER 1 INTRODUCTION 1.1 Urban impoundments Urban impoundments or dams provide aesthetically pleasing environments for people while serving as habitats for aquatic and terrestrial organisms. Local authorities maintain urban impoundments primarily for storm-water control, as habitats