MASTER'S THESIS. GIS-mapping of Fluoride Contaminated Groundwater in Nakuru & Baringo district, Kenya. Jörgen Näslund Ingemar Snell

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1 MASTER'S THESIS 2005:198 CIV GIS-mapping of Fluoride Contaminated Groundwater in Nakuru & Baringo district, Kenya Jörgen Näslund Ingemar Snell Luleå University of Technology MSc Programmes in Engineering Department of Civil and Environmental Engineering Division of Sanitary Engineering 2005:198 CIV - ISSN: ISRN: LTU-EX--05/198--SE

2 SUPERVISORS Sweden Jörgen Hanæus Professor Division of Sanitary Engineering Luleå University of Technology Luleå Sweden Kenya Susan Murcott Research Engineer Department of Civil and Environmental Engineering Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge, Ma USA Peter Jacobsen Technical Advisor Catholic Diocese of Nakuru, Water Quality Programme P.O. Box Nakuru Kenya KEYWORDS Minor Field Study, Kenya, Nakuru, Lake Baringo, GIS, Fluoride, Groundwater I

3 ACKNOWLEDGEMENT This Master s thesis constitutes our final degree project in Environmental Engineering at Luleå University of Technology, Sweden. The work was commissioned by The Ministry of Water, Nairobi, Kenya and Massachusetts Institute of Technology, USA. The project has been carried out as a Minor Field Study in Nairobi and Nakuru, Kenya during the period January April 2005 and was completed in May June in Luleå, Sweden. The field work was performed in Baringo District in the northern part of Rift Valley Province. This project has throughout the time continuously undergone changes. Changes in form of object, area, time, supervisors, organizations and people involved. The time in Kenya has been challenging but also very profitable and we are grateful that we got the opportunity to work in this interesting country. Despite that the project developed in a slightly different way from what we planned for in the beginning we hope that the result of this study will benefit the people of Kenya and be useful for the involved organizations. While working with this project we met and were introduced to many people. First of all we would like to send a great Thank You to our Professor, Jörgen Hanæus, at Luleå University of Technology for helping us with advice from Sweden. Also thanks for contacting and introducing us to Susan Murcott at Massachusetts Institute of Technology in the U.S. We would also like to thank the employees at the GIT (Geographic Information Technology) department in Luleå, especially Fredrik Salén, for the great support and supervising after we came back from Kenya. For all help and support in Kenya we would like to thank Susan Murcott at MIT, Peter Jacobsen and the rest of the people at Catholic Diocese of Nakuru Water Programme. You really made our visit pleasant and enjoyable. Without you we would still be struggling with inadequate information. Last but not least, we would like to thank the Swedish International Development and Cooperation Agency (SIDA) and Internationella Programkontoret for providing the main financial funding. To all the helpful people of Kenya that we met along the road: Asante Sana, you will not be forgotten! Luleå - Sweden, June 2005 Jörgen Näslund Ingemar Snell II

4 ABSTRACT This Master of Science thesis has been carried out in Nakuru and Baringo Districts in the Rift Valley Province in Kenya. The thesis was performed as a Minor Field Study (MFS) financed by the Swedish International Development and Cooperation Agency (SIDA), through the Internationella Programkontoret. High fluoride levels in the ground water are a major problem that leads to diseases related to a high fluoride intake amongst people. In the Rift Valley Province, Kenya the bedrock consists of fluoride bearing minerals which contaminate the water. High levels are more common in deeply drilled boreholes than in surface water. Catholic Dioceses of Nakuru (CDN) is a non governmental organization stationed in Nakuru working with defluoridation methods to remove fluoride from drinking water. In 1985 they started a Water Programme with extensive activity within water supply and quality. In their continuous work a GIS- map over fluoride levels in boreholes would be useful. This thesis summarizes the work with creating a GIS map. The map shows location and 6 other parameters of interest from 195 boreholes drilled by CDN. Except from the work with the GIS map this report also summarize results from a field study in an area around Lake Baringo in Baringo District. The aim with the field study was to investigate and overview the water situation. All in all 52 water sources were found, 7 permanent and 45 seasonal. The results and conclusions from the field study are presented in this report. They will hopefully facilitate the decision-making process for CDN. A CD with data files concerning the GIS-map can be received from Division of Sanitary Engineering at Luleå University of Technology. III

5 TABLE OF CONTENT 1 INTRODUCTION BACKGROUND OBJECTIVES AND SCOPE METHOD PREPARATORY STUDIES GIS-MAP OVER BOREHOLES IN NAKURU DISTRICT SURVEY OF THE WATER SITUATION AROUND LAKE BARINGO DESCRIPTION OF AREA AND ORGANIZATION REPUBLIC OF KENYA Geographic Regions Climate NAKURU DISTRICT BARINGO DISTRICT The area of investigation CATHOLIC DIOCESE OF NAKURU Background Choice of defluoridation method CDN Defluoridation Filters Household Filter Institutional Filter Community Filter Waterworks Filter PERFORMANCE PREPARATORY STUDIES DATA COLLECTION Nakuru Baringo DATA AND MAP PREPARATION Preparation of water characteristics data from CDN Preparation of data from Baringo District Preparation of digital spatial data layers Laboratory test methods RESULTS AND DISCUSSION FLUORINE Field of utilization Fluoride in water Distribution on earth Human exposure Health impacts and guideline values...25

6 7.2 FLUORIDE IN WATERS IN KENYA REMOVAL METHODS Choice of defluoridation method Activated Alumina Nalgonda Method Reverse Osmosis Bone char Chemical Processes in Fluoride Uptake on Bone Char NAKURU LAKE BARINGO SOURCES OF ERROR CONCLUSIONS RECOMMENDATIONS REFERENCES...42 LITERATURE...42 PERSONAL CONTACTS...43 INTERNET...43 APPENDICES APPENDIX 1 APPENDIX 2 APPENDIX 3 APPENDIX 4 APPENDIX 5 APPENDIX 6 APPENDIX 7

7 1 INTRODUCTION It all started at the United Nations Millennial Summit in New York in 2000 and appeared again at the United Nations Summit on Sustainable Development in Johannesburg in 2003, the international community signed on to the Millennium Development Goals a recommitment was made to sustainable development and the elimination of poverty. The seventh of the eight Millennium Development Goals is to halve by 2015 the proportion of people without sustainable access to safe drinking water (MDGs, 2004). In this context, the World Health Organization (WHO) was seeking proposals from qualified bidders on research, assessment and implementation of household drinking water treatment and safe storage technologies in developing countries. At the June 2004 meeting of the WHO International Network to Promote Household Water Treatment and Safe Storage (the Network), participants worked to create an achievable operations plan for the next 12 months that will help promote simple, low cost initiatives to treat and safely store water at the point of use. There have been three Network meetings in Geneva, Washington DC and Nairobi. Massachusetts Institute of Technology (MIT) faculty and staff from Civil and Environmental Engineering Department s Master of Engineering Program have been involved and are playing a leading role in the activities of the Implementation Working Group. Since 1999 MIT has performed project work on household drinking water treatment and safe storage (HWTS) in five different countries. The 2004/2005 year s Water and Sanitation in Developing Countries M.Eng. project was based in Kenya. This Master s thesis constitutes a small part of the MIT project in Kenya. 1

8 2 BACKGROUND High fluoride intake has since long been known to cause serious harm to people s health. Dental and skeletal fluorosis are two diseases that can be related to a too high and long exposure of fluoride. There are various ways of getting exposed to fluoride. In developing countries with presence of fluoride bearing bedrocks people are often involuntarily exposed to fluoride by drinking contaminated water. In some rural areas in Kenya the water situation is often strained between rain seasons. Because of that groundwater from boreholes becomes an important source during most time of the year. Good quality surface water is often lacking and people are forced to travel long distances to find water. In certain regions in Kenya problems with high fluoride content in the groundwater has led to a severe influence of fluoride related diseases among the people. It has long been a big concern for the country and the problem is well-known to the Kenyan Government. Measurements of fluoride levels throughout the country have been undertaken by the Ministry of Water and various non-governmental organizations for many years. The Ministry of Water in Nairobi holds a large quantity of data over the water situation in Kenya. The initial purpose for this study was that the Ministry of Water should support with data over the water situation (fluoride levels). Unfortunately the data was inaccessible for public due to the Kenyan bureaucracy. Instead data for this Master s thesis became based on information from the Non-Governmental Organization (NGO), Catholic Diocese of Nakuru (CDN). CDN is located in Nakuru and have run a water program for a little more than 20 years, mainly focusing on the area around the Rift Valley. When establishing new wells/water sources they file information about the source in the organization s archive. Since CDN was part of the HWTS project and had been working on the fluoride issue for many years they had great knowledge about the complex water situation in the area. They had developed different types of water filters based on bone char a.o. for removal of fluoride and were running pilot experiments for other types of water purification. The objectives were therefore based on desires from the Catholic Diocese of Nakuru in their continued work with improving the water situation and alleviate health hazards. 2

9 3 OBJECTIVES AND SCOPE In this study there were three main objectives. One of them was a comprehensive preparatory literature studies to initially summarize earlier experiences about the complex water situation in the country, fluoride removal from drinking water, diseases related to fluoride etc. Topic related studies should be done not only before but also during the work in Kenya. The readings should comprehend on such breadth and depth that the understanding of the situation in Kenya was clear and problems within the project could be solved. The second objective was to create a GIS-map over boreholes in Nakuru District. By using a GIS-software and borehole data from the Catholic Diocese of Nakuru a digitalized map showing boreholes in Nakuru District should be created. The map should show the location of the borehole and the specific fluoride levels in each well along with other water characteristics of interest. The goal with creating a GIS-map was to facilitate development work connected to prevailing water situation. In the present situation there is a need of getting a good overview of the water sources/boreholes for the government and the non-governmental organizations i.e. Catholic Diocese of Nakuru. The third and last objective was to survey the water supplies in the area around Lake Baringo in Baringo District. The aim was to collect information about location, use and condition of the water sources and present it to the Catholic Diocese of Nakuru. The water situation in the area, in terms of availability and quality, was relatively unknown. The purpose of the field study was to create basic data for decision making before implementing a new developed treatment plant for removal of fluoride. The gathered information should be put into the GIS-map as a spatial data layer. 3

10 4 METHOD 4.1 Preparatory studies The preparatory studies took place both in Sweden and in Kenya. Material was obtained from libraries but also from the Internet. In addition to the studies on printed material visits to different companies and communities working with water quality issues were carried out. 4.2 GIS-map over boreholes in Nakuru District Water quality data along with location and some user information data were received from the Catholic Diocese of Nakuru. The data were digitalized and unified and then presented on a digitalized map. 4.3 Survey of the water situation around Lake Baringo The survey of the water situation around Lake Baringo took place during a week-long expedition in the area. Different water sources were visited and people were interviewed about the source. Some water samples were collected and later analyzed for different parameters. Finally the location of each water source was set. 4

11 5 DESCRIPTION OF AREA AND ORGANIZATION 5.1 Republic of Kenya (EBO, 2005) Kenya is located on the African continent s east coast and covers an area of km 2. The capital is Nairobi and Kenya is bordered on the north by Ethiopia and Sudan, on the west by Uganda and Lake Victoria, on the east by the Indian Ocean and Somalia and on the south by Tanzania, see Figure 1. Figure 1 Map over Kenya The population who consists of more than 100 different ethnic groups comprises more than 31 million people of whom about 2,5 million lives in the capital Nairobi. More than half of the Kenyan population lives in poverty and resources are unevenly distributed, both between people and regions. The richest fifth of the population gets 50 percent of the income, while the poorest fifth gets 5 percent. High population growth, dry outs, floods and ethnical conflicts has worsen the living conditions for many Kenyans. Most of the poor people live in the rural areas but many of them moves to the bigger cities, where the slum increases. About half of the population has access to clean water. 5

12 5.1.1 Geographic Regions Kenya has three main geographic zones; the highlands, the semiarid lowlands and the deserts. There is a fourth, called the coastal zone, which occupies a narrow strip along the Indian Ocean. There are 8 administrative provinces (see Figure 2) divided into 68 districts, all with its own district capital. Figure 2 Map over Province Boundary Climate Although Kenya is located on the equator most of the country has a temperate climate and that is because of the high altitude. Along the coast is the climate tropical. Kenya has two wet seasons and two dry seasons. The rainy seasons extend from March to May and from November to December. The precipitation is unevenly distributed over the country. The amount of rainfall is greatest in the highlands, located on the west, and in the coastal zones on the east side. The lowlands deserts of the north receive the least amount of rain. 6

13 5.2 Nakuru District Nakuru district is located in the west province of Rift Valley and has a total population of (EBO, 2005). Figure 3 shows the location of Nakuru district. The capital is Nakuru and the district is divided into 16 administrative subdivisions. Of the 7242 km 2 land area 176 km 2 constitutes surface water sources. In Nakuru like in many other districts in Kenya, water has become so scarce, especially surface water, making the only option to be ground water. Figure 3 Map over District Boundary, Nakuru The district can be subdivided into roughly three water basins namely Nakuru West, Nakuru North and Nakuru East. Among the three, Nakuru West is generally endowed with a lot of streams traversing it. Nakuru West contributes a large part of the catchment area that drains into Lake Victoria. The area is seriously being affected by deforestation due to human settlement. Forest is cleared by those who settle in order to pave way for agricultural activities which has led to a change in underground water recharge. On the Eastern side there are very few rivers. Most of the water sources consist of boreholes and shallow wells. 7

14 In the Northern side there are few streams and rivers which have little flow during the dry season. Apart from rivers, streams and boreholes, there are also lakes, dams and pans. The lakes found in Nakuru district are; Lake Nakuru, Lake Naivasha, Lake Elementaita and Lake Solai. Lake Nakuru is a popular tourist attraction due to its flamingos and rhinos. Lake Naivasha is a fresh water lake and is important for horticulture and fishing. Lake Elementaita is like Lake Nakuru saline and famous for its flamingoes. Lake Solai is relatively smaller than the rest of the lakes and has also saline water. Water in Nakuru is generally for domestic, livestock, industrial and irrigation purposes. In rural areas, water is generally for domestic and livestock while in urban areas it is for industrial purposes. The quality of water is fairly good especially the surface water in the Western part except for micro-organisms. In places where boreholes are the major sources of water i.e. the Eastern part, the fluoride levels have been noted to be high (CDN Handout, 2005). 8

15 5.3 Baringo District (Ministry of Finance and Planning, 2002) Baringo district is located in the northern part of Rift Valley Province and has an area of 8,655 km km 2 of the area is surface water sources. Administratively, the district is divided into 14 divisions. The districts headquarter is located in Kabarnet and the total population for Baringo is (EBO, 2005). Figure 4 shows the location of Baringo district. Figure 4 Map over District Boundary, Baringo Baringo District can be divided into three agro-ecological zones namely the highlands, midlands and lowlands. The highlands are characterized by hills known as the Tugen Hills that are at an average altitude of 2000 meters above sea level. The average annual rainfall is 1200 mm and the average annual temperature is 25 C. These conditions coupled with the fertile volcanic soils make the highlands conductive for crops and dairy farming. The midlands, where part of the field study for this report took place, are inhabited by agro-pastrolists, as rainfall is not adequate for crop farming. This area is endowed with the only three perennial rivers in the district namely; Perkerra, Molo and Kerio Rivers but none of them runs through the area of this study. The lowlands in the district have an average altitude of about 700 meters above sea level and most of it is rangeland. Temperatures in this zone are above 32 C and the 9

16 average annual rainfall is about 600 mm. These conditions are not conductive for crop farming and therefore livestock rearing is the main economic activity. Facts about Baringo district can be seen in Table 1. Table 1 Baringo district facts Area Total area 8655 km 2 Arable area 2515 km 2 Non-arable area (including water masses) 6143 km 2 Water mass 140,5 km 2 Topography and Climate Altitude Highest 2300 meters Lowest 600 meters Rainfall Annual Average for long rains Highlands 900 mm Lowlands 500 mm Annual Average for short rains Highlands 300 mm Lowlands 100 mm Temperature range Highest temperatures January-March 35 C Lowest temperatures July 16 C Annual average temperature Highlands 25 C Lowlands 35 C The area of investigation The area around Lake Baringo where the field study took place is located in the midland zone and covers an estimated area of 100 km 2, see Figure 5. The physiographic and natural conditions are arid like the rest of the midlands. The majority of the people earn their living as agro-pastorals (goat farming) or fishermen. Another important income source for the area is tourists who come to see the wildlife and hot springs around the lake. Kampi ya Samaki, located at the western shore of Lake Baringo, is the main village with around 3500 inhabitants. The estimated population in the area covered in the field study was 6000 people. The infrastructure is poorly developed and large parts of the area are sparsely populated. Many people live in mud huts and poverty is widespread. Water scarcity is present throughout the year except for the rain seasons. 10

17 Figure 5 Map over the area of investigation 5.4 Catholic Diocese of Nakuru For this Master s thesis; GIS-mapping of Fluoride Contaminated Groundwater in Nakuru & Baringo, Kenya, there are three organizations involved except Luleå University of Technology; The Ministry of Water, Nairobi, Kenya; Massachusetts Institute of Technology, USA and Catholic Diocese of Nakuru, Nakuru, Kenya. The co-operation with CDN has been of great importance for the outcome of this report and because of that a circumstantial description of their organization is made in the following part of the report. 11

18 5.4.1 Background After a catastrophic drought that hit Kenya in 1984 the Catholic Diocese of Nakuru decided to create a Water Programme. The CDN Water Programme started in 1985 and serves the civil districts of Nakuru, Baringo, Koibatek, Kericho, Bomet and Buret. Kericho is a separate Diocese since Today the Programme employs around 60 people, as it has been growing during the years, and operates in several areas. Among the major are: drilling of deep wells, construction of water schemes and construction of rainwater harvesting water tanks. Figure 6 shows the sign outside the CDN office in Nakuru. Figure 6 Sign outside CDN, Nakuru During the work with implementing various water projects one of the objectives has been the provision of safe water. The water provided by the Programme was however not always safe. It became apparent that high levels of fluoride in the water made it unsafe for cooking or drinking, especially the water from deep boreholes. The issue of high fluoride levels became a major concern for the CDN Water Programme and in 1997 the Programme applied to Misereor, Germany for a grant to develop methods for removal of fluoride for use in rural communities. In the beginning of 1998 the program started after the application was approved. 12

19 5.4.2 Choice of defluoridation method When the CDN Defluoridation Programme started in 1998 it was not quite clear which defluoridation method to use. The bone char method seemed to have some interesting advantages in a rural setting but had not been implemented in a larger scale before. The main advantages are: All material used are locally available, all chemicals and spares can be purchased in local hardware stores in Kenya. The required regular maintenance is extremely minimal. There is no addition of chemicals, no cleaning is needed. High efficiency, regardless of the amount of fluoride in the raw water. Practically all fluoride is removed. Low cost No hazardous chemicals used No health risks involved. However there are also some disadvantages using the bone char method: There is very little experience available using bone char in rural settings. A few pilot implementations had been made in Thailand and Tanzania, but no major implementation had been reported in the literature. Regeneration of the filters when bone char becomes saturated requires caustic soda and acid and must be done by technically trained people, not by local communities. Regeneration must be carried out regularly, perhaps a few times per year, depending on the size and usage rate of the system CDN Defluoridation Filters When this report is written CDN offers four different types of filters Household filters, small and large Institutional filters Community filters, 3 sizes Filters for water works (10 40 liter/day) ( liter/day) (500 20,000 liter/day) (up to 2,000,000 liter/day) Contact Precipitation is a new method under development at CDN in Nakuru, involving calcium and phosphate mixed in the water and reacting before the bone char is involved in the defluoridation process (Jacobsen P., 2005). 13

20 5.4.4 Household Filter The household bone char defluoridation systems are comprised of one or two 20 liters buckets depending on the design, see Figure 7. This filter is designed to supply a household (5 12 people) with fluoride free water for drinking and cooking. The filters are robust and inexpensive, but they do not utilize the filter material as efficiently as the community scale filters. The filter material can not be regenerated; it must be changed after saturation. The household filters are made in two sizes. The small type contains 12 liters of filter material and the bigger one contains 24 liters. The bone char filtration media reduces fluoride concentration from an initial concentration of 5 15 mg/l to less than 1.5 mg/l (Jacobsen P. 2005). Changing the media to new media in a household bone char filter is a simple process and requires no technical skill. Figure 7 Household filters Institutional Filter The institutional scale filters are designed for institutions or larger kitchens where filters can be connected to the normal water supply systems. These filters are constructed using standard PVC tanks of 650 liters, containing about 450 liters of filter material. The cost is currently 39,000 KES, not including installation. No regular maintenance is required; the daily operation does not differ from operating a standard water storage tank. Depending on the concentration of fluoride in the raw water and the filter size, the filter material needs regeneration or changing at regular intervals, typically every ½ to 3 years. 14

21 5.4.6 Community Filter The community scale bone char defluoridation systems supply 1,000 to 5,000 or more people with water for drinking and/or cooking. They are suitable where users collect their water at a central water point. The community plant is basically a 4 or 12 m 3 ferrocement tank filled with filter material and equipped with screen and connections for regenerating the filter. The structure is quite solid and suitable for public places, see Figure 8. The sizes range from 2,500, 5,000 or 10,000 liters of filter material (Jacobsen P., 2005). The appropriate choice depends on the consumption of water and the fluoride concentration in the water. As well as the institutional filter a community scale filter needs regeneration of the filter material when it s saturated with fluoride. This should be done at regular intervals, typically every 3 23 month, depending on the consumption and fluoride concentration. Figure 8 Model of Community filter Waterworks Filter The waterworks scale bone char defluoridation systems are similar to the institutional or community filters but consists of two or more of the larger filters coupled in series. The filters are designed to be regenerated more frequently, every 2 to 8 weeks, but this can be done without disrupting the running of the defluoridation plant. Regeneration is carried out on one of the larger filters while the other ones are in use (Jacobsen P., 2005). 15

22 6 PERFORMANCE In this section the methods used for preparatory studies, data collection and preparation and the water source investigation in Baringo will be explained more in detail. 6.1 Preparatory studies The search for literature about Kenya, fluorine and fluoride removal techniques in general started at Luleå University of Technology in December The studies took place at the University Library with access to all their material. Except going through books and articles in the library search for literature was done on the World Wide Web and in databases such as BiblioLine, GeoRef and Science Direct. The preliminaries involved contacts with different companies and municipally representatives in Sweden familiar with the problematic of high fluoride levels in groundwater. In Kenya, most of the initial time was spent getting to know the different organizations involved in the project. Among other things participation in a work shop held at Kenyan Water Institute and a visit to the Non-Governmental Organization ApproTEC were done. Some additional literature studies were carried out in Nakuru with material from CDN. 6.2 Data Collection The data collection can be divided in two parts. The performance when collecting data to the GIS-map in Nakuru and the performance when collecting data during the field study in Baringo Nakuru In Nakuru CDN kept a large quantity of data over boreholes in their archive. The amount of data was extensive considering the time available in Kenya for this project since the number of boreholes drilled and filed exceeded 360 at the time for this study. The data files in the archive were reviewed and relevant information was photographed with a digital camera. In that way all necessary information could be stored in digital format and brought to Sweden without risk of loosing or missing some important information when leaving Kenya. Some of the information from the files had already been documented by CDN so that information was also brought to Sweden and compiled with the new information. To be able to present the borehole data in a clear way; good and accurate maps were needed. The intention was to get digitalized maps showing Kenya in general but Nakuru and Baringo districts in detail. The CDN Head office in Nakuru was visited as some earlier GIS work had been done by one of the employees. Unfortunately the 24 topographic maps from CDN s previous work covered just parts of the required area and 16

23 were therefore not usable for this project. The Provincial Headquarter in Nakuru was also visited but only paper version maps were available. Due to regulations the maps could not be brought out of the office and were therefore impossible to digitalize. Also permits, which involve a difficult and time-consuming procedure to get, were required to be allowed to copy the maps. As a last attempt to get digitalized maps some time in Nairobi was spent in meetings with authorized personnel at the Maji House. Information was given that one department at the Ministry of Water had worked on the preparation of digitalized maps. After two weeks spent running back and forth between the different departments the operation was cancelled with no successful outcome. The reason why the maps were inaccessible for this study is not clear. Either the Ministry of Water refused to hand out the information or the information did not exist. The first alternative is the most likely Baringo Data from the field study were collected during a week-long visit to the area around Lake Baringo. The geographic conditions in Baringo and the economic situation for this project made the way of transportation a key issue. After discussion and deliberation with CDN, bicycles seemed to be the best option. To avoid getting lost a local guide was hired who also worked as an interpreter when interviewing the inhabitants. The area of investigation was located west of Lake Baringo, in Marigat, Bartabwa, Kabartonjo and Kipsaraman division. Starting point for the daily adventures was the village Kampi ya Samaki. Both seasonal and non-seasonal water sources were visited during the research and great importance was put on the talks with users. An example of a shallow well is shown in Figure 9. People were interviewed about where they get water, how they use the water source, quality of the water, diseases related to the use of water, how far they have to walk/travel to the source etc. In addition to the information from the people, pictures were taken at some major water sources to emphasize the use of water. The gathered impressions for each water source were documented in a notebook along with the GPS coordinates and other information. 17

24 Figure 9 A shallow well outside Kampi ya Samaki Except oral information 20 water samples were collected and later analyzed for electrical conductivity, ph, fluoride content, turbidity and settleable solids in the CDN laboratory. When there was water in the source the turbidity was estimated with a simple field instrument. There were desires from CDN that the microbial content in the drinking water should be determined but unfortunately that request was impossible to fulfill. It was not possible to bring the equipment for measurements of microbial content to the source. Heat in combination with the time to bring the samples to a laboratory would have made the results unreliable. The nearest laboratory was the CDN laboratory in Nakuru, by car hours away. 18

25 A Magellan GPS 320 (Global Positioning System) device was used to decide the position of all water sources, both seasonal and non-seasonal, see Figure 10. GPS is a fast and rather exact method and accurate enough for this type of investigation. 10 Positioning with GPS device Figure 6.3 Data and Map Preparation The outcome and quality of the GIS-map is all dependent on the quality of the data you put in. It is important to prepare the data carefully and uniform, especially when the work is to be continued by other users Preparation of water characteristics data from CDN After the data from the CDN files were reviewed, photographed and brought to Sweden it was compiled in an excel sheet together with the other data received from CDN. Not all data given from CDN was to be put into the map so some additional edits were done. A few parameters like Q-yield and tube material were left out since they did not constitute relevant information for this study. To avoid mixing up data all names and characteristics given by the CDN were kept intact. 19

26 Certain portions of location data were given in degrees, minutes and seconds format (DDDMMSSS) while others were in degrees, minutes and hundredths of minutes format (DDDMMMMM). To unify all location data and to make them readable in ArcView they were transformed into WGS84 (World Geodetic System of 1984), decimal degree format, with assistance of a standard transformation system. After all data were reviewed the table was converted into dbase IV format to be readable in ArcView Preparation of data from Baringo District From notes during the field study the collected data, location, type of source, type of construction, durability and number of users were transferred to excel sheets. Analyzes of the water samples performed by CDN were added to the other data. After putting all information into the excel sheet the sequence of work for making the data readable in ArcView was the same as the procedure for water characteristics data from CDN Preparation of digital spatial data layers The spatial data layers over Kenya were acquired from ESRI s Data & Maps 2000 CD. There were no maps found that only covered Kenya, Nakuru and Baringo on the CD so the world map was used. On the world map there are many options for the spatial data layers although the detail abundance is not very good. The information kept in dbase IV format was converted to ArcView shape files. Wells location and additional parameters for Nakuru and Baringo District were prepared with the help of ArcView. 20

27 6.3.4 Laboratory test methods The water samples from Baringo field trip were analyzed by the employees at CDN laboratory, see Figure 11. Same test methods as the samples collected by CDN (from boreholes) themselves were used. Figure 11 Staff at the CDN laboratory The test methods follows the "Standard Methods for the examination of Water and Wastewater" published by American Public Health Association and American Water Works Association. Turbidity test -Nephelometric Method (Standard Methods, 1995, 2130B) Electrical Conductivity - Ele Paqualab operating instructions ph Value - Electrometric Method (Standard Methods, 1995, 4500-H + A) Fluoride test - Ion Selective Method (Standard Methods,1995, 4500-F - C) Settleable Solids - Volumetric Method (Standard Method, 1995, 2540F) Equipment: ELE Paqualab Turbidity meter ELE Paqualab Conductivity meter Metrohm 713 ph meter Fluoride (ion selective) electrode: Solid state membrane, Metrohm no Reference Electrode: Glass membrane, Metrohm no ph meter (mv meter): Metrohm 713 ph meter Imhoff cone 21

28 7 RESULTS AND DISCUSSION Below follows the results of this study. The preparatory studies started in Sweden in January 2005, before the three months of field work in Kenya, and lasted until June when the report was completed. The literature study comprised studies about Kenya, fluorine and its field of application, removal techniques, health hazards and guideline values. The results from the preparatory study are given in chapter 7.1 to 7.3. In chapter 7.4 the results from the GIS-mapping of the boreholes in Nakuru are presented and last, in chapter 7.5, the results from the field study in Baringo District are presented. 7.1 Fluorine Fluorine (F 2 ) is in its elementary form a greenish, highly reactive, diatomic gas. It has atomic number 9 in Mendeleyev s Periodic Table and is the most reactive and electronegative of all known elements. Because of its high reactance fluorine rarely occurs free in nature. It generally combines with other elements to form fluorides and is normally found as the fluoride ion (F - ) in minerals. Information about the fluorine proportion in earth s crust differs in almost every report. Among others the Ministry of Health in New Zealand uphold that it is 17 th most common element in the earth's crust and that earth s crust contains about 900 parts of fluoride per million (ppm) (MoH, 2005). Others uphold that it s the 13 th most abundant (Gikunju, J.K. et al., 1992) and comprise 0,065 0,07 % of the earth s crust (NE, 2005, Dicciani N., 2003). There are only two rock-forming minerals, topaz (Al 2 SiO 4 (F,OH) 2 ) and fluorite (CaF 2 ), that have fluorine as an essential part in their formula. Other minerals with fluorine as a major component are: fluorspar or fluorite (CaF 2 ), cryolite (NaAlF 6 ) and fluorapatite (3Ca 3 (PO 4 ) 2 CaF 2 ). Those minerals are common accessory minerals in various rock formations; fluorspar in limestone and sandstone (sedimentary rocks) and cryolite in granite (igneous rocks) (Bulusu K.R. et al., 1979). Fluorapatite, by far the commonest of the apatite group, is present in almost all igneous rocks and many of the sedimentary and metamorphic rocks (Deer W.A. et al., 1966) Field of utilization Although fluoride has many fields of applications it is perhaps most commonly known as a component in toothpaste, where it works as a beneficial agent. It is proved that low levels of fluoride provide some protection against caries, which is the main reason for adding fluoride to toothpaste. In 1945 early observations of fluoride s caries prevention properties led to experimental addition of fluoride to drinking water in several countries. According to Grandjean [1982] 22

29 in 1982 more than 200 million individuals received artificially fluorinated drinking water worldwide, with 95 million of them residing in the United States. Fluorochemicals also underscore a wide range of commercial successes. Growth in the industrial and household refrigeration and air conditioning industries is based largely on the use of low-toxicity, nonflammable, and energy-efficient fluorocarbon fluids. Fluoropolymers and fluoroelastomers are used widely in homes, buildings, automobiles, aerospace applications, and wherever high performance such as excellent thermal, flame, electrical, chemical, and solvent resistance and low oxygen and moisture permeability is required (Dicciani N., 2003) Fluoride in water Since some fluoride compounds in the earth's upper crust are soluble in water, fluoride is found in both surface waters and groundwater. In streaming surface freshwater, fluoride concentrations are usually lower than in groundwater because the shorter contact time between water and rock. The natural concentration of fluoride depends on the geological, chemical and physical characteristics of the aquifer, the porosity and acidity of the soil and rocks, the temperature and the action of other chemical elements (UNICEF, 2005). Another reason for high fluoride concentrations in groundwater can be the absorption of uprising, subterranean gas containing high levels of fluoride (Deer W.A. et al., 1966) Distribution on earth Fluoride bearing bedrocks and fluoride contaminated water occurs in all parts of the world including large parts of Africa, China, the Middle East and Southern Asia, see Figure 12. There are 2 major belts with known high fluoride levels where extensive studies have been carried out. One belt is the East African Rift from Eritrea to Malawi and the other is the belt which stretches from Turkey through Iraq, Iran, Afghanistan, India and northern Thailand to China. The Americas and Japan have similar belts but with generally lower fluoride levels. 23

30 Figure 12 Map over countries with endemic fluorosis due to excess fluoride in drinking water Fluoride is often found in higher concentrations in areas where there have been volcanic activities. In the Kenyan Rift Valley the bedrock and soil consists of Quaternary and Tertiary volcanics and unconsolidated sediments (Gaciri S.J. et al., 1993), both rich in fluoride bearing minerals (Nanyaro J.T. et al., 1984). Despite the frequent occurrence of fluoride, its wide field of applications and broad extension throughout the world the essentiality for humans has not been demonstrated unequivocally. On the contrary, many studies on the adverse effects of a too high fluoride intake have been carried out and the knowledge of the diseases related to the problem is good Human exposure There are various ways of getting exposed to fluoride. The World Health Organization list in their monograph Fluorides in Drinking Water (Fawell J.K., 2003) 4 different ways; Air, Water, Food and Dental uses. When searching for material it seems like most studies have been done for the water way of exposure. In Kenya, when talking to authorized people in the Ministry of Water and other water organizations concerning exposure way, water overshadows the other ways. The anxiety is supported by Fawell J.K. (2003) considering that: In areas with relatively high fluoride concentrations in groundwater, drinking-water becomes increasingly important as a source of fluoride (Fawell J.K., 2003). 24

31 7.1.6 Health impacts and guideline values Because the fact that fluoride is widely dispersed in the environment, all living organisms are extensively exposed to it and tolerate in modest amounts. In humans, overexposure of fluoride results in accumulation of the element in the mineralizing tissues of the body. The symptoms become visible even with small exposure. In young people fluoride accumulates in both teeth (dental fluorosis) and bones (skeletal fluorosis) while in older people overexposure of fluoride causes skeletal fluorosis only. Figure 13 shows a boy with dental fluorosis. Results of examination of children s teeth in Njoro Division, Nakuru District show that 48,3% of the children suffer from moderate to severe dental fluorosis (Nyaora Moturi W.K. et al., 2001). Figure 13 Boy with dental fluorosis, Kampi ya Samaki Primary School Skeletal fluorosis is a complicated illness with a number of stages. The first two stages are preclinical where changes have already taken place but with no notable pain or symptoms for the patient. The next two stages are clinical where symptoms include pains in the bones and joints; sensations of burning, pricking, and tingling in the limbs; muscle weakness; chronic fatigue; and gastrointestinal disorders and reduced appetite (FAN, 2005). When exposed to a very high level of fluoride intake under a longer time skeletal fluorosis can grow in to the most severe form, crippling skeletal fluorosis. In crippling fluorosis the extremities become weak and moving the joints is difficult. Also dental fluorosis occurs in different stages. There are two indexes; Dean s Fluorosis Index (Dean H.T., 1942) and TF (Thylstrup-Fejerskov) Index (Thylstrup A. et al., 1978), which describes the severity of the illness. Both Dean s and Thylstrup-Fejerskov s Index have different levels from not visible signs to severe affected enamel (FAN, 2005). 25

32 The reason why children become affected by dental fluorosis while adults don t is the mineralization of teeth which takes place at about months of age (Fawell J.K., 2003). During that period children are extra sensitive and a damage that occurs lasts for the rest of their life. Numerous, all by each other independent studies have proved relations between fluorosis and daily intake of fluoride. Manji et al. (1986) showed in his study about dental fluorosis in an area with 2 ppm fluoride in the drinking water that 50% of the children had pitting in their teeth exhibiting a TF Index level of 7 or higher (Manji F. et al., 1986). The level of fluorosis is not entirely connected to a certain level of fluoride in the drinking water. The effects depend on the total intake and vary between people. The World Health Organization has recommended a guideline value for drinking water of 1,5 mg F/l. It was set in 1984 and reaffirmed in 1993 and Drinking water with concentrations above this value carries an increasing risk of dental fluorosis. Much higher concentrations lead to skeletal fluorosis. In Kenya the Kenya Bureau of Standards follows the WHO guideline value and recommends a maximum of 1,5 mg F/l for drinking water (Gikunju J.K. et al., 2002). 7.2 Fluoride in waters in Kenya The catchment basins in East Africa are composed primarily of basic volcanic rocks; therefore fluoride is likely to be present in water in these areas (Gikunju J.K. et al., 1995). Clear and accurate information about the situation with fluoride in natural waters of Kenya today is somewhat difficult to find. Extensive studies have been carried out by different research teams during the last 50 years but most of them are dated between 1960 and Later studies focus most on the effects of fluorosis among the population and/or levels of fluoride in certain district or subdistricts in Kenya. Some papers show results from studies made on different water sources; river water, streams/springs, tap water, boreholes or rain water. Any literature about comprehensive studies done recently has not been found. In interviews with people responsible for water quality at the Department for Water and Pollution Control in Nairobi it was found that the awareness of the problems associated with high fluoride levels in drinking water is good. Also the awareness of which regions in the country that have particularly severe problems is good. On the other hand, the knowledge about the fluoride level of a specific water source in a certain region is lacking. 7.3 Removal methods Several methods for removal of fluoride from drinking water have been described in the literature, but only a few are used in praxis. The methods differ from each other in technique, arrangement, performance and material. The process of removal of fluoride is generally termed as defluoridation or defluorination. 26

33 7.3.1 Choice of defluoridation method When evaluating the effectiveness and suitability of a method one has to know the condition in which the defluoridation plant will be used. Defluoridation in a remote rural village obvious requires another approach than in a water work for a big city. When selecting a defluoridation method the following parameters should be considered. Efficiency: o Can the defluoridation reduce the fluoride level to acceptable values (i.e. below 1, 5 mg F/l)? Running of the plant: o Level of required supervision, dependency of electricity, complexity of operation (i.e. dosing of chemicals). Cost of defluoridation, both with respect to establishing the plant and to the running costs. Maintenance of the plant, costs and availability of spare parts. Possible negative impacts (i.e. hazards): o Handling of dangerous chemicals, consequences of wrong dosing of chemicals, inefficient fluoride removal and possible chemical residual in the treated water. Supply of chemical for defluoridation. The selection of method should reflect the local situation and none of the method could be termed as best without careful consideration of all points. The choice of method is therefore dependent on the local possibilities. The defluoridation techniques, based on the nature of processes, can be grouped under following categories (Mariappan P. Unknown): Adsorption and Ion exchange Precipitation Electrochemical method and Membrane Technique The materials and methods for defluoridation are tabulated in Table 2. 27

34 Table 2 Material and methods to remove fluoride Adsorption Ion exchange Precipitation Others Carbon Materials Wood, Lignite Coal, Bone Petroleum residues Nut shells, Pady husk Avaram bark Coffee husk, Tea waste Jute waste Coconut shell Coir pith, Fly ash Carbion, Defluoron-1 Defluoron-2 Activated alumina KRASS, Bauxite Serpentine Clay minerals Fish bone, Calcite Bio-mass NCL polyanion Resin Tulsion A27 Lewatit-MIH- 59 Amberlite IRA- 400 Deacedodite FF-IP Waso resin-14 Polystyrene Lime Alum Lime and Alum (Nalgonda Technique) i) Fill and Draw ii) Continues flow iii) Package Treatment plant for HP Alum floc blanket method Poly aluminium chloride (PAC) Poly aluminium hydroxy sulphate (PAHS) Electrochemical (Aluminium electrode) Electrodialysis Reverse Osmosis Activated Alumina Activated alumina is the most successful and the most often used absorbent for fluoride removal. Boruff was the first man to study the absorbent properties of activated alumina in 1934 and contact beds of activated alumina have now been used for many years in municipal water treatment plants for removal of fluoride. In many cases activated alumina appears to be technically feasible and economically viable. It is available in a range of granule sizes and is able to adsorb as much as 1,4g fluoride per 100g product (Azizian F., 1993). At normal ph values fluoride is absorbed from and hydroxide is released to the water. For regeneration the process can be reversed by raising the ph values. Main advantages are the simplicity of normal operation and the efficiency; fluoride can be reduced to practically any desired levels Nalgonda Method In the Nalgonda method alum and lime are added to the raw water. Fluoride attaches itself to the flocs of aluminum hydroxide, which are formed and can be removed from the water together with precipitated flocs (CDN Handout, 2005). The use of the Nalgonda method has apparently had some success in India and the method can be implemented both in households and in water works (NEERI, 1987). The main advantages in the Nalgonda technique are, its low cost and the availability of the lime and alum. There are some major drawbacks like the lack of required efficiency, the requirement of adding 28