Physico-chemical pollution pattern in Akaki River basin, Addis Ababa, Ethiopia

50 Pages·2012·1.59 MB·English

Department of Physical Geography
and Quaternary Geology
Physico-chemical pollution
pattern in Akaki River basin,
Addis Ababa, Ethiopia
Ferezer Eshetu Tegegn
Master’s thesis NKA 55
Physical Geography and Quaternary Geology, 30 HECs 2012

Preface

This Master’s thesis is Ferezer Eshetu Tegegn’s degree project in Physical Geography and
Quaternary Geology, at the Department of Physical Geography and Quaternary Geology,
Stockholm University. The Master’s thesis comprises 30 HECs (one term of full-time
studies).

Supervisors have been Jerker Jarsjö and Steve Lyon at the Department of Physical Geography
and Quaternary Geology, Stockholm University. Examiner has been Andrew Frampton, at the
Department of Physical Geography and Quaternary Geology, Stockholm University.

The author is responsible for the contents of this thesis.

Stockholm, 7 June 2012

Lars-Ove Westerberg
Director of studies
Ferezer Eshetu Tegegn
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Physico-chemical pollution pattern in Akaki River basin, Addis Ababa, Ethiopia
ABSTRACT
The present study focuses on the analysis of physico-chemical parameters: electrical
conductivity, nitrate and phosphate in the Akaki River basin of Addis Ababa, Ethiopia.
These secondary water quality parameters were obtained from two different sources: the
surface water quality data both for Little and Great Akaki were retrieved from Addis Ababa
Environmental Protection Agency (AAEPA). Whereas, the groundwater quality data for
four water wells were obtained from Addis Ababa Water and Sewerage Authority
(AAWSA). These water quality parameters have been determined in order to assess the
pollution levels of Akaki River basin. The values of the parameters have been evaluated
with respect to the maximum acceptable standard level of WHO (World Health
Organization) for surface and drinking water.
The outcome of the study observed absence of spatial and temporal pattern both on surface
and groundwater but displayed a huge variation. The result also showed increasing
concentration and variation of all parameters inside and outside the city of Addis Ababa
with increasing industrialization and urbanization. Comparison also showed that the little
Akaki is highly polluted as compared to Great Akaki River.
The ground water chemistry also showed a high phosphate load in all of the productive
wells. On the contrary, all the wells displayed nitrate level below WHO standard and they
are free from Nitrate.

KEY WORDS: Addis Ababa, Ethiopia, Physico-chemical, Little and Great Akaki, AAEPA,
AAWSA, Spatial, temporal.

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Ferezer Eshetu Tegegn
ACKNOWLEDGEMENT

I am very thankful to my two advisors: Jerker Jarsjö and Steve Lyon for their endless
support and comment throughout my work. I am grateful to my only mother, Etetu
Yiemenu for encouraging me to continue with my second master’s degree. Great
appreciation also goes to her best friend, Addis Ababa Lisanework, for paving the road to
get me all the contacts in the data departments both in AAEPA and AAWSA and providing
me all the information I needed through her tireless e-mail. I would like to pass my deepest
gratitude to Selome Tessema for producing many of the idea in the very baby stage of my
project. The last but not least, I would like to express my respect and my heart full
appreciation to my life time friend, my room-mate, Simon Merid for tipping me part of the
statistical part and many more.

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Physico-chemical pollution pattern in Akaki River basin, Addis Ababa, Ethiopia
ABBREVIATION AND ACRONYM
MER Main Ethiopian Rift
TDS Total dissolved solid
mg/l Milligram per liter
NH Ammonia
3
BOD Biological Oxygen Demand
COD Chemical Oxygen Demand
Fe Iron
Pb Lead
TA Total Alkality
TH Total Hardness
CaH Calcium Hardness
MgH Magnesium Hardness
MPN Most Probable Number
NE Northeast
SW Southwest
E-W East to West
N-W North to West
S-E South to East
AAEPA Addis Ababa Environmental Protection Agency
AAWSA Addis Ababa Water and Sewerage Authority
SPSS Statistical Package for the Social Sciences
UCL Upper Control Limit
LCL Lower Control Limit
WHO World Health Organization
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Ferezer Eshetu Tegegn
µ Mean
Standard deviation
n The total number of data points

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Physico-chemical pollution pattern in Akaki River basin, Addis Ababa, Ethiopia

Table of Contents
ABSTRACT ............................................................................................................................................. v
ACKNOWLEDGEMENT ......................................................................................................................... vi
1. INTRODUCTION ........................................................................................................................... 1
1.1. STUDY AREA ........................................................................................................................ 4
1.2. GEOLOGY AND HYDROGEOLOGY ........................................................................................ 7
2. MATERIALS AND METHODS ........................................................................................................ 9
2.1. WATER QUALITY PARAMETERS ......................................................................................... 10
2.1.1. PHYSICAL PROPERTIES ............................................................................................... 10
2.1.2. CHEMICAL PROPERTIES ............................................................................................. 11
3. RESULT ...................................................................................................................................... 13
3.1. SURFACE WATER ............................................................................................................... 13
3.1.1. ELECTRICAL CONDUCTIVITY ...................................................................................... 13
3.1.2. NITRATES ................................................................................................................... 15
3.1.3. PHOSPHATE ..................................................................................................................... 16
3.2. GROUNDWATER ................................................................................................................ 18
3.2.1. Electrical conductivity ............................................................................................... 18
3.2.2. Nitrate ....................................................................................................................... 19
3.2.3. Phosphate ................................................................................................................. 20
4. DISCUSSION ............................................................................................................................... 22
4.1. Potential pollution sources ............................................................................................... 22
4.1.1. Industrial sources ...................................................................................................... 22
4.1.2. Municipal sources ..................................................................................................... 23
4.1.3. Natural Factor ........................................................................................................... 24
4.2. Spatial and temporal variability of water parameters ...................................................... 24
5. CONCLUSION ............................................................................................................................. 28
6. RECOMMENDATION ................................................................................................................. 29
7. REFFERENCE .............................................................................................................................. 31
8. APPENDIX .................................................................................................................................. 33
8.1. Physical Parameters .......................................................................................................... 33
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Ferezer Eshetu Tegegn
8.2. Chemical Parameters ........................................................................................................ 34
8.3. Bacteriological parameters ............................................................................................... 38

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