University of Zimbabwe Faculty of Engineering Department of Civil Engineering EFFECTS OF MINING ACTIVITIES AT BULYANHULU GOLD MINE (BGM) ON THE WATER QUALITY OF BULYANHULU RIVER: SHINYANGA - TANZANIA By GRACE NKULI A Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science Intergrated Water Resources Management June 2008 Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania CERTIFICATION The undersigned certifies that they have read and hereby recommend for accepta nce by the University of Zimbabwe a thesis entitled : Effects of Gold mining activities on the water quality of Bulyanhulu River : The case of Bulyanhulu Gold Mine in Shinyanga, Tanzania in fulfillment of the requirements for the degree of Master of Science (Integrated Water Resources Management) of the University of Zimbabwe. ……………………………………….. S. Misi. (Dr) ………………………………………. Z. Hoko. (Eng) Date ……………………………………… MSc. (IWRM) Thesis by Grace Nkuli June 2008 i Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania DECLARATION I, Grace Michael Nkuli, declare that this thesis is my o wn original work (except where acknowledged) and that it has not been presented and will not be presented to any other University for any other degree award. Signature……………………………… Date…………………………………. MSc. (IWRM) Thesis by Grace Nkuli June 2008 ii Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania ACKNOWLEDGEMENTS Usually it is not easy for anyone to write a thesis of this length and importance in the given time without some external assistance. In view of this fact, I hereby whole heartedly thank the almighty God for everything and those in one way or the oth er, extended their help to me during the course of writing this thesis and so enabling me presenting in time to the respective Faculty of Engineering at the University of Zimbabwe. This work is a product of assistance, advices, guidance and counseling from different people, institutions, organizations and departments. I am indebted to all those who made the success of this work. Thanks for the University of Zimbabwe (Civil Department) and to “WaterNet” for a scholarship. I wish to thank specifically my Supervisors Dr. Misi and Eng. Hoko (University of Zimbabwe) and Dr. Kimwaga (University of Dar es Salaam) for their determined supervision. Their advice and guidance from proposal write-up, presentations, fieldwork, laboratory work, data analyses and thesis w rite-up to submission are highly appreciated. Special thanks to Prof. M.A. Kishimba, Head of ANCAP at the University of Dar es Salaam for his assistance, encouragement and advice. My fellow postgraduate students whose relevant academic material I had acces s to especially Miss Hazel Mphande you are a wonderful friend. Sincere thanks to the Bulyanhulu Gold Mine (BGM) Management for allowing me to do my research at BGM and by providing facilities, guidance and support for the whole period of my study in particular the General Manager Mr. Greg Walker, Environmental Manager Mr. Shoo Korodias, Human resources Manager Mr. Gervas Chapalwa, GIS specialists Ernest Kika & Genes Mkumbo, EHS Manager Mr. Juma Malunga, Environmental coordinator Mr. Thobias Mathew, Officers Mackenzie Bujiku, Freddy Mkisi, Angelo Kitula, Bertha Johnson, Simon Mwaluko, Nura Kalegeya and all members of staff who also assisted in doing the research. Acknowledgement is also due to Barrick Analytical laboratory ; in particular to Mr Ashok Kumar (Chemist), T. Bahemuka (Chemist) and D. Salum (Chemist) for making my work possible by giving me water analysis practical training and their technical assistance in the laboratory. I would also like to thank Mr. Sephton Ross for his guidance and assistance in reviewing the BGM Water Quality Programme. Finally, yet very special, my heartfelt acknowledgement to my husband Mr. Martin L. Mgallah for his love and patience in missing my presence for most of the time I was carrying this study, my family as a whole, relatives and friends for their very strong encouragement, perseverance and support. I can not mention all as the list is endless; however my heart-felt thanks are extended to all those who in one way or another contributed to make the completion of thi s hard and long work possible. MSc. (IWRM) Thesis by Grace Nkuli June 2008 iii Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania DEDICATION This dissertation is dedicated to: My Loving Parents Modesta and Michael The Family of Mr. & Mrs. Mlolwa My Husband Martin My Sister and My Brothers MSc. (IWRM) Thesis by Grace Nkuli June 2008 iv Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania ABSTRACT This study assessed the effects of mining activities at Bulyanhulu Gold Mine (BGM) on the water quality of Bulyanhulu River in Tanzania. Potential pollutants were identified, quantified and their spatial distribution determined along different sampling points upstream and downstream the mine. The water quality of the river and groundwater in the area is of importance as the water is used for agriculture and domestic purposes. Grab samples were collected from Bulyanhulu River, shallow wells, Effluent Control Ponds (ECP’s) and boreholes during the period January-March 2008 and analyzed for Temp, 2+ - - pH, EC, SO4 , Fe, Ni, Ag, As, Hg, CN , NO3 and Zn according to Standard methods. The pH values in water samples were 6.3 ± 1.4 in ECP, 7.0 ± 0.2 in river, 5.9 ± 0.4 i n boreholes and 5.2 ± 0.3 in wells. The conductivity in ECP, river, boreholes and wells sample were 1969 ± 470 μS/cm, 207 ± 46 μS/cm, 1023 ± 497 μS/cm and 203 ± 112 2+ μS/cm respectively. The mean SO4 concentrations in ECP, river, boreholes and well sample points were 1014 ± 353 mg/l, 70 ± 30 mg/l, 497 ± 205 mg/l and 181 ± 0 mg/l. The temperature values were 26 ± 1 °C for ECP, 24 ± 1 °C for the river, 25 ± 1°C for - boreholes and 24 ± 1 °C for wells. Values of NO3 for ECP were 5 ± 1 mg/l, 4 ± 2 mg/l for river, 5 ± 3 mg/l for boreholes and 4 ± 3 mg/l for wells. Results for Ag were 0.1 ± 0.1 mg/l for ECP, 0.1 ± 0 mg/l for the river, 0.1 ± 0 mg/l for boreholes and <0.005 mg/l for wells. Results for Ni were 0.7 ± 0.3 mg/l for ECP, 0.4 ± 0.3 mg/l for the river, 0.04 ± 0.03 mg/l for boreholes and 0.2 ± 0.1 mg/l for wells. Concentrations of Fe for ECP were 7.2 ± 3 mg/l, 2.9 ± 0.13 mg/l for the river, 0.3 ± 0.4 mg/l for boreholes and 0.2 ± 0.13 mg/l for wells. Concentrations of Zn in ECP, river, borehole and well samples were 13.0 ± 7.0 mg/l, 1.8 ± 0.8 mg/l, 4.0 ± 2.0 mg/l and 2.5 ± 0.8 mg/l. Water quality of the Bulyanhulu River, shallow wells and monitoring boreholes were compared against Tanzanian maximum permissible concentration and WHO drinking water quality guidelines while Effluent Control Pond values were compared against the Tanzanian effluent discharge maximum permissible concentration guidelines. The concentrations of As, Hg and CN- were low (below method detection limit). The high concentrations of these param eters could be attributed to weathering of sulphide ore bodies, chemicals used in the process plant, decomposition and leaching of discarded batteries and old metal scraps in mine areas. These elements could relatively have high toxicological effects in the environment, biota and health hazards to human beings especially in the mining communities. It was concluded that, the water quality of the river is polluted with respect to Ni, Fe and slightly by Zn and was therefore, considered not suitable for human consumption. 2+ Groundwater quality was affected by mining activities with respect to pH, EC, SO 4 , Ni 2+ and Zn however; EC and SO4 affected the boreholes more. The ECP’s showed highest mean concentrations of all elements studied. It is therefore, recommended to treat the effluents in the ECP’s by precipitating out metals thus reducing their mobility through seepage. The existing monitoring Programme for BGM needs improvement. MSc. (IWRM) Thesis by Grace Nkuli June 2008 v Effects of gold mining activities on the water quality of Bulyanhulu River: The case of Bulyanhulu Gold Mine in Shinyanga - Tanzania CONTENTS CERTIFICATION………………… …………………………………………………… ..i DECLARATION .............................................................................................................. ii ACKNOWLEDGEMENTS ............................................................................................ iii DEDICATION ................................................................................................................. iv ABSTRACT....................................................................................................................... v CONTENTS ..................................................................................................................... vi LIST OF TABLES ......................................................................................................... viii LIST OF FIGURES ......................................................................................................... ix LIST OF APPENDICES .................................................................................................. x ACRONYMS ...................................................................................................................