Groundwater Contamination with Toxic Metals
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University of Ghana http://ugspace.ug.edu.gh GROUNDWATER CONTAMINATION WITH TOXIC METALS THROUGH SMALL SCALE MINING WITHIN THE LOWER PRA BASIN BY MICHAEL DORLEKU (10363066) BSc. (Hons) Laboratory Technology (UCC) THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON, IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF M.PHIL. ENVIRONMENTAL SCIENCE DEGREE JUNE, 2013 University of Ghana http://ugspace.ug.edu.gh DECLARATION I hereby declare that this research and all the experimental work described therein were solely carried out by me under the Institute of Environmental Science and Sanitation, University of Ghana, Legon, under the supervision of Prof. D. Carboo and Dr. D. Nukpezah. No previous submission for a degree has been made here or elsewhere. References cited therein were duly acknowledged. Student.............................................. Date...................................... (Michael Dorleku) SID: 10363066 Principal Supervisor....................................... Date.......................................... (Prof.D. Carboo ) Supervisor................................................. Date................................................. (Dr. D. Nukpezah) ii University of Ghana http://ugspace.ug.edu.gh DEDICATION This thesis is dedicated to the Ancient of Days, the Lord Jesus Christ, whose I am. To my wife and my three lovely children Daisy, Elsie and Edlyn. iii University of Ghana http://ugspace.ug.edu.gh ACKNOWLEDGEMENTS I am grateful to the almighty God through my Lord Jesus Christ for His abundant grace, love, protection and provision throughout this study. I appreciate the tremendous assistance of my supervisors, Prof. D. Carboo of the Department of Chemistry and Dr. D. Nukpezah of Institute of Environmental Science and Sanitation for their guidance towards the completion of this thesis. I wish to sincerely thank the Director, Dr Joseph A. Ampofo, the Administrator, Mrs. A. Sedziafa and Dr O. Ansa-Asare all of CSIR-Water Research Institute for their support in allowing me pursue this course. I also want to thank Mr Collins Tay of CSIR-WRI for his tremendous support and Dr. Isaac Hodgson also of the same institute for his encouragement and mentorship to make me a better person. Last but not the least, my thanks goes to the technical staff of Environmental Chemistry Division of Water Research Institute especially Mr Lawrence Yawson and Mr Daniel Amoah for helping me do my work whilst I was away for the post graduate studies. iv University of Ghana http://ugspace.ug.edu.gh TABLE OF CONTENTS Page DECLARATION................................................................................................................... ii DEDICATION....................................................................................................................... iii ACKNOWLEDGEMENTS.................................................................................................... iv TABLE OF CONTENTS....................................................................................................... v LIST OF TABLES................................................................................................................ ix LIST OF FIGURES.............................................................................................................. x LIST OFAPPENDICES........................................................................................................ xi ABSTRACT......................................................................................................................... 1 CHAPTER ONE.................................................................................................................. 2 1.0 INTRODUCTION.................................................................................................... 2 1.1 Background............................................................................................................ 2 1.2 Statement of the Problem.................................................................................... 7 1.3 Aim and Objectives................................................................................................ 8 1.3.1 Specific Objective............................................................................................... 8 CHAPTER TWO................................................................................................................ 9 1.0 LITERATURE REVIEW......................................................................................... 9 2.1 Water Resources ................................................................................................. 9 2.2 Small scale Gold Mining....................................................................................... 11 2.3 Methods of Mining.............................................................................................. 14 v University of Ghana http://ugspace.ug.edu.gh 2.4 Methods of Processing...........................................................................................15 2.5 Environmental, Health and Safety Impact of Small scale Mining...........................16 2.5.1 Environmental Impact......................................................................................... 17 2.5.1.1 Land Degradation............................................................................................. 17 2.5.1.2 Deforestation..................................................................................................... 17 2.5.1.3 Water Pollution................................................................................................. 17 2.5.1.4 Acid Rock Drainage......................................................................................... 18 2.5.1.5 Mercury Pollution.............................................................................................. 19 2.5.1.6 Airborne Particulate Matter............................................................................... 21 2.5.2 Safety and Health Impacts.................................................................................. 20 CHAPTER THREE........................................................................................................ 24 3.0 MATERIAL AND METHODS............................................................................... 24 3.1 Study Area......................................................................................................... 24 3.1.1 Location............................................................................................................ 24 3.1.2 Climate ............................................................................................................ 25 3.1.3 Vegetation........................................................................................................ 25 3.1.4 Topography and Drainage............................................................................... 25 3.1.5 Geology and Soil............................................................................................. 26 3.1.6 Economic Activities......................................................................................... 26 3.2 Sample Collection................................................................................................ 27 3.3 Laboratory Analysis............................................................................................. 27 3.3.1 Determination of Total Metals........................................................................... 27 3.3.1.1 Sample Preparation and Analysis.............................................................. 27-28 3.3.1.2 Determination of Phosphate......................................................................... 28 3.3.1.3 Determination of Sulphate............................................................................. 28 vi University of Ghana http://ugspace.ug.edu.gh 3.3.1.4 Determination of Nitrate................................................................................ 29 3.4 Quality Control.................................................................................................. 29 3.5 Statistical Analysis.............................................................................................. 29 CHAPTER FOUR............................................................................................................ 30 4.0 Results............................................................................................................... 30 4.1 Physical Parameters........................................................................................... 30 4.1.1 pH, Temperature and Conductivity.................................................................. 30 4.2 Metal Results...................................................................................................... 34 4.3 Nutrient Results.................................................................................................. 45 CHAPTER FIVE............................................................................................................. 48 5.0 DISCUSSION...................................................................................................... 48 5.1 Physical Parameters............................................................................................ 48 5.1.1 pH of Water Sample.......................................................................................... 48 5.1.2 Temperature....................................................................................................