Arsenic Contamination of Groundwater in South- Western Part of Ashanti Region of Ghana A thesis approved by the Faculty of Environmental Sciences and Process Engineering at the Brandenburg University of Technology in Cottbus-Senftenberg in partial fulfillment of the requirement for the award of the academic degree of Doctor of Philosophy (Ph.D.) in Environmental Sciences. by Master of Philosophy Crentsil Kofi Bempah Born in Kumasi, Ashanti Region, Ghana Supervisor: Prof. Dr. rer. nat. habil. Hans-Jűrgen Voigt Supervisor: Prof. Dr. rer. nat. Rainer Herd Day of the oral examination: 04.11.2014 Arsenic Contamination in Groundwater DECLARATION This doctoral dissertation “Arsenic Contamination of Groundwater in South-Western Part of Ashanti Region of Ghana” was completed and written independently by me Crentsil Kofi Bempah. I hereby declare that: 1. This Ph.D. thesis was completed and written independently and that all used sources and tools are indicated in the thesis. 2. The publication of the thesis does not violate any copyright rules. All other work and/or words of others are appropriately cited or quoted. 3. I have never applied for a doctoral degree award in BTU or any institution before; or submitted any earlier applications to obtain permission for final examination or publication of my doctoral degree in part or in whole. 4. There has never been an instance where my application to get permission for final examination or publication of a doctoral degree has been cancelled, disqualified or unsuccessful due to my attempt to deceive. The research is an accurate and original account of my work done under the framework of the Environmental and Resource Management doctoral program offered by the Brandenburg University of Technology, Cottbus-Senftenberg. It includes objectives, discussion of results, accurate representation of underlining data and detailed referencing of all sources and tools used. ----------------------------------- Date: 04.11.2014 Crentsil Kofi Bempah Lehrstuhl Umweltgeologie Brandenburg University of Technology, Cottbus-Senftenberg Chair of Environmental Geology, BTU I Arsenic Contamination in Groundwater ACKNOWLEDGEMENT The path that took me to this Doctoral Thesis has been paved with the support of several people to whom I owe my deepest gratitude. First of all, I would like to express my sincere thanks to my principal supervisor, Prof. Dr. Hans-Jürgen Voigt who has given inspirational guidance, willing support, scientific and motivating discussion throughout my study. Without his able guidance and tutelage, this research would never have been completed successfully. My sincere gratitude goes to my second supervisor, Prof. Dr. Rainer Herd for his invaluable suggestions, constructive criticisms and corrections which proved indispensable in the preparation of this thesis. Dr. Christian Lorenz and Dr. Anthony Ewusi deserve special mention for their constructive comments and useful suggestions. Their engagement and help in proofreading this manuscript helped me much to complete this research. Words could not express my sincere gratitude to Prof. E.H.K Akaho; former Director General of Ghana Atomic Energy Commission for his foresight, dedication and kindness for granting me study leave to study in Germany. I also wish to express my utmost gratitude to Katholischer Akademischer Ausländer-Dienst (KAAD) for granting me scholarship to successfully complete this PhD research. I must thank Ms. Simone Saure, officer of KAAD for her support and help for my daily life and travels in and out of Germany. I really appreciated the contact to all the members of the Obuasi Municipal Assembly, Bekwai Municipal Assembly, Amansie West, Amansie Central and Adansi North District Assemblies for answering my questions and providing more than scientific information. A wealthy acknowledgment goes to Mrs. Ansah Asare for giving me a space in her home to conduct As removal technology. Moreover, my special acknowledgments go to all-rounder Benjamin Agyei (Papa Attah) and my bachelor students from University of Ghana and University of Cape Coast for their enduring help. Without them, the fieldwork wouldn’t have been done in this short time. Further, I appreciated the help of George Tetteh Ashiagbor, APERL GIS Center at the Faculty of Forest Resources Technology, KNUST, for his assistance during the processing of the GIS data. Chair of Environmental Geology, BTU II Arsenic Contamination in Groundwater Special thanks to Daniel Ayerebi Ansong, Agya Asabere and Solomon Obiri Yeboah for their permanent encouragement during the difficult periods of my work. Thanks to Francis Mensah, Dr-Ing. Roy, Emmanuel Ambe, Theodore, Ing. Kobla and John Kesita for their patience and help to get some distraction from my work if it was necessary… Years seem very long to last, but I am grateful to my family, most especially to my darling mother and father as well as my revered in-laws for their support with words of encouragement and prayers as well as their reminder that they have been waiting for me and I should work hard, so that these long days need not to be wasted. I reckon it is impossible to have my research career without the massive support, love and encouragement from my dearest wife, Mrs. Juliana Bempah and my two wonderful children, Naana Abena Achiah Bempah and Oheneba Nana Yaw Kankam Bempah. This work could never have been completed without their encouragement and good will messages they sent across the miles. Through their unconditional love, they have been constant source of moral support that has helped make my dream come true. Chair of Environmental Geology, BTU III Arsenic Contamination in Groundwater DEDICATION This thesis is dedicated to my beloved wife Mrs. Juliana Bempah, my treasured son Oheneba Nana Yaw Kankam Bempah and my dearest daughter Naana Abena Achiah Bempah. Chair of Environmental Geology, BTU IV Arsenic Contamination in Groundwater TABLE OF CONTENTS DECLARATION......................................................................................................................... IV ACKNOWLEDGEMENT .......................................................................................................... IV DEDICATION............................................................................................................................. IV TABLE OF CONTENTS. .......................................................................................................... IV LIST OF TABLES. ..................................................................................................................... IX LIST OF FIGURES. ................................................................................................................... XI LIST OF ABBREVIATIONS. ................................................................................................ XIV UNITS OF MEASUREMENTS................................................................................................ XV ABSTRACT IN ENGLISH ..................................................................................................... XVI ABSTRACT IN DEUTSCH .................................................................................................... XVI CHAPTER ONE ............................................................................................................................. 1 1.0 GENERAL INTRODUCTION ................................................................................................. 1 1.1 Background ............................................................................................................................. 1 1.2 Justification ............................................................................................................................. 4 1.3 Hypotheses ............................................................................................................................... 6 1.4 Objectives of the Research ..................................................................................................... 7 CHAPTER TWO ............................................................................................................................ 9 1.0 HYDROGEOCHEMISTRY AND ARSENIC CONTAMINATION IN THE ENVIRONMENT – A LITERATURE REVIEW .......................................................................... 9 2.1 Introduction ............................................................................................................................. 9 2.2 Arsenic in the Environment ................................................................................................. 10 2.3 Arsenic in Groundwater ....................................................................................................... 11 2.4 Geochemistry of Arsenic Release to Groundwater ............................................................ 16 2.5 Arsenic Behavior and Speciation ......................................................................................... 19 2.6 Groundwater Flow and Transport ...................................................................................... 23 2.7 Arsenic Exposure and Human Health ................................................................................ 24 2.8 Analytical Methods for Arsenic Determination in Drinking Water ................................ 28 2.9 Arsenic Removal Technologies ............................................................................................ 34 2.10 Mining Related Arsenic Problems in Ghana, an Overview ...........................................