POLLUTION OF PROTECTED SPRINGS IN RELATION TO HIGH AND
LOW DENSITY SETTLEMENTS IN KAMPALA – UGANDA
Nsubuga, F. B.a Kansiime, F. b* and Okot-Okumu, J. b
a
Bukalasa Agricultural College, P.O. Box 8352 Kampala, E-mail = fnbwanika@yahoo.com.
b
Makerere University Institute of Environment & Natural Resources, P.O. Box 7298 Kampala-Uganda. (*
Corresponding author; Fax 256 41 530134; e-mail = fkansiime@muienr.mak.ac.ug).
ABSTRACT
In Kampala City like most towns in Uganda, provision of treated piped water has been concentrated in
high-income zones with very little improvement in the high-density, low-income areas where the
majority of the urban population lives. This has left protected springs as a major source of domestic
water. These springs are “protected” during construction by providing provisions in two parts; a
permeable section of gravel and sand into which the source waters enter, and a dam which prevents the
water from bypassing the catchment or reservoir. A perforated supply pipe leads the water out of the
reservoir. Very few studies have been carried out to determine the extent of pollution of protected
springs and none on the comparison of protected springs in high- and low-density settlements. This
study, carried out both in the dry and wet seasons, was aimed at establishing the water quality of
protected springs in Kampala and contributory pollution factors. Both high- and low-density settlement
areas were studied. Survey using questionnaires and field observations were done to identify sources of
pollutants and to relate them to human activities and explain the possible causes and sources of
pollution of the springs.
Pollution (chemical and biological) levels were higher in protected springs located in high-density
settlement areas and this was attributed to poor waste-management practices. Human activities like
construction of pit latrines, some located less than 5 m upstream of protected springs, animal husbandry
1
and indiscriminate dumping of wastes contributed to the presence of high levels of chemical and
biological pollutants in the protected springs. Average concentrations of nitrate-nitrogen (49.5 mg/l)
and ammonium-nitrogen (7.3 mg/l) and faecal coliforms (1.8*10 4 no./100mls) were recorded. Pollution
levels were higher in the rainy season and this was attributed to storm water runoff and its infiltration
into the ground water. The results indicate that water from protected springs poses a health risk to the
communities using it.
Key words: Pollution, protected springs, settlements, Kampala, Uganda
INTRODUCTION
In many of the largest cities, the impact of unsewered sanitation on groundwater quality may not be
significant, because municipal water supplies are drawn from surface water and treated, or drawn from
relatively distant and deep, well-protected aquifers. Often the most serious water pollution problems
arise from medium- to small-sized towns and in densely populated peri- urban and rural areas, where
local shallow and often untreated groundwater sources are used for domestic purposes. In these
circumstances, direct pollution of the source at springs by the users, by livestock and by wastewater,
may be a serious problem (Chapman, 1996).
World wide, water-borne diseases are a major cause of morbidity and mortality in humans (WHO,
1996). Water-borne pathogens infect around 250 million people per year, resulting in 10-20 million
deaths (Anon, 1996). Many of these infections occur in developing nations, which have sanitation
problems, associated with low socio-economic conditions and of little public health awareness.
Millions of people world-wide continue to rely on shallow groundwater sources and on-site sanitation.
It is therefore important to develop an understanding of the causes of contamination of groundwater
when considering the potential for improvement in water supplies and sanitation (van Ryneveld &
Fourie, 1997).
2
Kampala, the capital city of Uganda, has experienced a rapid population growth as a result of natural
growth and migration. A relatively large population of urban poor has emerged, resulting in
development of high-density, low-income settlements with poor sanitary facilities. Pit latrines are the
predominant forms of disposal of human excreta. The wastewater from pit latrine, septic tanks and
soakaway pits may seep into groundwater. Some households do not have sanitation of any sort. Poor
solid waste management in Kampala City contributes to high levels of leachates that consequently
pollute groundwater (State of Environment, 2000).
National Water and Sewerage Corporation (NWSC), which is charged with provision of piped water in
Uganda has, largely covered the high-income zones with very little improvement in piped water supply
to the high-density, low-income areas where the majority of the urban population lives (State of
Environment, 2000). Groundwater is the alternative source of domestic water obtained from springs
apart from boreholes and dug wells. The city authorities have “protected” springs in an attempt to
improve the quality of water. These springs are supposedly protected during construction by providing
provisions in two parts; a permeable section of gravel and sand into which the source waters enter, and
a dam which prevents the water from bypassing the catchment or reservoir. A perforated supply pipe
leads the water out of the reservoir. The low-income population with access to protected springs uses
them for all their domestic water needs including drinking and cooking (Howard et al, 2000).
There have been continuous outbreaks of water-borne infectious diseases like cholera, dysentery and
typhoid fever in Kampala City. The most notable was the cholera epidemic of 1997/1998, the likely
cause of which was contaminated water. Studies (Nasinyama et al, 2000) have suggested a link
between the incidences of the cholera epidemic to the use of contaminated protected springs. The same
authors also reported a correlation between the use of non-piped- water and acute diarrhoea.
This paper reports on a study done to determine the quality of water from protected springs to establish
the cause-effect relationship between high- and low-density settlements and pollution of protected
spring. The sources of pollutants were identified, the levels of pollutants in drinking water were
determined, and the human activities that relate to observed sources of pollutants were identified.
3
METHODS
STUDY AREA
Kampala District had a population of 4,727-persons/Km2 (Population and housing census 1992) but
density has increased to about 7,378 persons / Km2 (Population and housing census 2002/2003,
provisional results). Kampala has five administrative divisions. Two divisions, namely Kawempe and
Makindye, were selected for the study, Figure 1. In each division, two parishes with protected springs
were selected at random in high-density settlement areas (a population density of 9,000-12,999
persons/ Km2) and the other two, from low-density settlement areas (0-1999 persons/ Km2), thus in all
eight (16) protected springs were studied. Water samples from protected springs were collected in the
dry and wet seasons.
FIELD OBSERVATIONS AND ASSESSMENT OF HUMAN ACTIVITIES
On-site visual observations were done to assess the condition of the ‘protected springs’ and their
environment. The number and distances of residences and pit latrines from the springs was determined.
The type of pit latrines, that is, whether above ground (built in water logged area with stance on four
walls that form the receptacle for human waste) or under ground, was also established. Presence of
solid waste dumps or scattered garbage was determined. Direct interviews were held with residents
using semi-structured questionnaires. They were submitted to fifteen households that collect water
from each protected spring making a total of one hundred and twenty households interviewed.
Information gathered from the interviews included the type of houses they had, the methods of human
waste disposal, the sources of drinking water, methods of garbage disposal, whether they reared
animals and the most common diseases that affected them.
4
5
Fig. 1. Map of Kampala district showing the protected springs studied.
WATER QUALITY ASSESSMENT
Measurement of chemical parameters and bacteriological indicators were carried out in the laboratory.
Samples for laboratory analyses of chemical parameters were collected in clean 500ml plastic bottles.
Clean sterilised glass bottles (250 ml) were used for collecting bacteriological samples. Samples were
stored and transported in an icebox and analyses were done within six hours of sampling. Sampling
and field measurements were carried out once a week for five consecutive weeks in the dry and wet
seasons.
Chemical parameters determined were ammonium-nitrogen and nitrate-nitrogen. These parameters
were chosen as indicators of pollution due to limited funding and availability of consumables and
equipment to the researchers. Ammonium-nitrogen was determined by Nessler’s spectrophotometric
method (APHA, 1992). Nitrate-nitrogen was determined by the Cadmium reduction method according
to standard methods (APHA, 1992). In both cases concentrations were measured using the HACH DR
4000 Spectrophotometer. Precision and accuracy of the spectrophotometer and procedures used for
analysis of samples were counter checked by measuring the concentration of known standards.
Bacteriological parameters determined were faecal coliforms and faecal streptococci. Faecal coliforms
were enumerated using the Membrane Filtration Method, using the membrane lauryl sulfate broth as a
6
test medium. Incubation was done at 44 C for 16-18 hours. Faecal streptococci were enumerated
using the Membrane Filtration Method, using the enterococcus agar as a test medium. Incubation was
done at 44 C for 48 hours. In both cases procedures of sample preparation and analysis followed
standard methods (APHA, 1992).
DATA ANALYSIS AND STATISTICAL METHODS
Statistical analysis was done using the Minitab release 12.22 for Windows. Descriptive statistics were
used to determine the mean and standard deviation of the variables. Normality tests (Andersondarling) were performed to determine whether the data are normally distributed. Count data for faecal
coliforms and faecal streptococci were not normally distributed and were therefore log-transformed.
One-way analysis of variance (ANOVA) was used to test the overall difference between the means of
the variables at the different sites (protected springs) in each division and multiple comparison
(Dunnett’s test) to test which means were different from the others. The symbols =, , and  have been
used to show levels of significance, where =means ‘not significantly different’,  means ‘significantly
lower than’, and  means ‘significantly higher than’.
RESULTS
FIELD OBSERVATIONS
An on-site evaluation revealed that the storm water drainage channels of the protected springs located
in the low-density settlement areas were well maintained by de-silting and by cutting grass along them.
The nearest pitlatrines were constructed 20m away from the protected springs and residences were
located at least 15 m away. However, the protected springs located in the high-density settlement areas
were poorly maintained and without upstream storm water diversion ditches. There was a lot of rubbish
thrown around the springs. The nearest pitlatrine was 0.5m away and there were residences all around.
7
Some of the pitlatrines were the above-ground type.
VARIATION OF WATER QUALITY OF THE SPRINGS
Tables 1 and 2 show averages of parameters measured during wet and dry seasons. Protected spring
water was rated with the Uganda National Bureau of Standards (UNBS) for drinking water quality. It
was also rated according to the National Guidelines for Rural Drinking Water Quality (NGRDWQ).
Table 1. Mean values ( standard deviations) of nitrogen compounds and bacterial counts at different springs in
Kawempe, (n=5)
WET SEASON
Parameter
DRY SEASON
NGRD
UN
WQ
BS
KLd1
KLd2
Khd1
Khd2
KLd1
KLd2
Khd1
Khd2
NH4-N (mg/l)
0.20.1
0.20.1
0.20.1
1.61
0.30.2
0.30.1
0.40.1
2.30.1
1-3
0.5
NO3-N (mg/l)
6.43.1
4.33.1
11.17
8.43.2
19.91
7.54.0
31.12
27.11
20-50
10
1
5
2
FC (no./100ml)
101
56
229
18262
38
31
303
1746
0-50
0
FS (no./100ml)
15
11
18
2763
2
3
28
86
0-50
0
FC= Faecal coliforms, FS = Faecal streptococci
K=Kawempe Division, M=Makindye Division, L=Low density, h=High density
NGRDWQ = National Guidelines on Rural Drinking Water Quality (maximum levels accepted)
UNBS = Uganda National Bureau of Standards (maximum levels accepted).
8
Table 2 Mean values ( standard deviations) of nitrogen compounds and bacterial counts at different protected
springs in Makindye, (n=5)
WET SEASON
Parameter
DRY SEASON
NGRD
UN
WQ
BS
MLd1
MLd2
Mhd1
Mhd2
MLd1
MLd2
Mhd1
Mhd2
NH4-N (mg/l)
0.50.2
0.50.3
0.30.1
7.30.1
0.30.1
0.3
0.40.1
21
1-3
0.5
NO3-N (mg/l)
6.22
163
7.42
214
2014
2212
2219
5028
20-50
10
FC (no./100ml)
382
333
423
645
128
43.6
257
495
0-50
0
FS (no./100ml)
457
173
76
4
93
16
10
2
0-50
0
Abbreviations are as indicated for table 1.
In Kawempe Division, the mean values of nitrate-nitrogen at locations KLd1, Khd1, and Khd2 (19.9,
31.1, and 27.1 mg/l) were much higher than the UNBS for drinking water quality (10 mg/l) except in
location KLd2 (Table 1) in the dry season. Analysis of variance among sites (Degrees of freedom 1-38)
revealed that the mean values of nitrate-nitrogen were not significantly different (p = 0.086). This could
be attributed to the high variability (as can be seen from the standard deviations) of the nitrate–nitrogen
concentrations especially at Khd1.
At location Khd2 the mean concentration of ammonium-nitrogen (2.32 mg/l) was high compared to
requirements for drinking water, UNBS (0.5 mg/l) and the NGRDWQ (1-3 mg/l). Analysis of variance
(ANOVA) among sites revealed that the mean values of ammonium-nitrogen were significantly
different (p = 0.001). Following ANOVA, multiple comparisons revealed that location KLd1 = KLd2
= Khd1  Khd2. The spring located at Khd2, which is a high-density settlement area, had the highest
mean value of ammonium-nitrogen. The average results of the chemical parameters were much higher
in the high-density settlement areas. In the wet season, the mean concentrations of nitrate-nitrogen and
ammonium-nitrogen at the different springs were lower and this could be attributed to the dilution
9
effect caused by rainfall. ANOVA showed no significant difference (p = 0.086) in mean values of
nitrate-nitrogen while mean values of ammonium-nitrogen were significantly different (p = 0.001).
In Makindye Division, the mean concentrations of nitrate-nitrogen at locations MLd1 MLd2, Mhd1 and
Mhd2, (being 19.8, 22.1, 21.9, and 49.5 mg/l respectively), were much higher than the UNBS (10 mg/l)
for drinking water quality. The average result of nitrate-nitrogen (49.5 mg/l) at location Mhd2 was
near the maximum limit of the NGRDWQ (20-50 mg/l). This indicated that the protected spring in
location Mhd2 was highly contaminated with nitrate-nitrogen (Table 2). In both the wet and dry
seasons ANOVA showed no significant difference (p = 0.086) in mean values of nitrate-nitrogen while
mean values of ammonium-nitrogen were significantly different (p = 0.001) similar to the observation
in Kawempe division.
VARIATION IN BACTERIOLOGICAL INDICATORS
In Kawempe division, the average numbers of faecal coliforms in the water samples collected from
protected springs were much higher than the UNBS (0 colonies /100mls) for drinking water quality.
Water samples collected from the protected springs Khd1 and Khd2, located in the high-density
settlement areas were higher than the NGRDWQ (0-50 colonies./100ml). The average numbers of
faecal streptococci in the water samples at locations KLd1, KLd2, Khd1, Khd2, (being 2.4, 2.4, 28,
96.2, no./100mls respectively), were higher than UNBS for drinking water quality but they were within
the NGRDWQ except at location Khd2 (Table 1)
Water samples taken from the high-density settlement areas of Khd1 and Khd2 had high numbers of
both faecal coliforms and faecal streptococci (Figure 2). The analysis of variance of the logarithms of
the means of faecal coliforms revealed significant differences (p = 0.001) between sites. Following
analysis of variance, multiple comparisons revealed that the average log counts of faecal coliforms at
location KLd1 = KLd2  Khd1 = Khd2, (the respective mean values being 38.2, 35.4, 303 and 1750
10
no/100ml). This implies that sites Khd1 and Khd2 that are high-density settlement areas had the
highest numbers of faecal coliforms.
Water samples taken from all the sites during the wet season had higher numbers of both faecal
coliforms and faecal streptococci than those taken during the dry season. This may be attributed to an
increase in contaminated rainwater run-off that ends up in protected springs as a result of an increase in
rainfall.
In Makindye Division, the average numbers/100ml of faecal coliforms in the water samples collected
from protected springs at locations MLd1, MLd2, Mhd1, and Mhd2, (being 133, 43.6, 257, and 495,
no./100mls respectively), were much higher than the UNBS (0 no. /100mls) for drinking water quality
and the NGRDWQ (0-50 no./100mls (Table 2). The average no./100mls of faecal streptococci in the
water samples were also higher than UNBS for drinking water quality but they were within the
NGRDWQ. The analysis of variance of the logarithms of the means of faecal coliforms revealed
significant differences (p = 0.003) between sites. Following analysis of variance, multiple comparisons
revealed that the average log counts of faecal coliforms at location MLd1 = MLd2  Mhd1 = Mhd2,
(the mean values being 133, 43.6, 257 and 495 no./100ml respectively) implying that sites Mhd1 and
Mhd2 had the highest numbers of faecal coliforms. These were high-density settlement areas.
Analysis of variance to test the difference in means of log counts of faecal streptococci at various sites
within Makindye Division showed no significant differences (p = 0.137) between the sites. Water
samples taken from protected springs located in the low-density settlement areas had higher numbers of
faecal streptococci than those collected from the high-density settlement areas. This could be attributed
to presence of livestock units that were observed in the low-density settlement areas.
The average numbers of faecal coliforms and faecal streptococci in the water samples examined, were
higher in the wet season This could be attributed to the fact that in the wet season there is an increase in
storm runoff resulting in an increase in levels of pollutants in protected springs.
11
THE SOCIO-ECONOMIC ACTIVITIES OF RESIDENTS
A total of 120 respondents completed the questionnaire. Most respondents were female (67%) and were
20-40 years of age (83%). Most respondents lived in either semi-detached houses (40%) or in small
one-roomed houses (55%), which were cheap to construct or to rent. A total of 76% of the respondents
had houses that were semi-permanent that is, houses whose construction was not completed. These
results reflect the poor economic status of the respondents.
None of the respondents had flush toilets. All had pit latrines, of which 77% were below-ground pit
latrines and 23% were aboveground pit latrines, located at distances of 1-2m from the springs (Table
3).
Table 3: Types of latrine and corresponding distances from the protected spring.
Type of pit latrine
Distance from protected spring in meters
1
2
3
4
5
6
8
9
10
11
Below-ground (%)
0.83
4.17
15
3.33
19.2
6.7
3.3
4.2
4.2
15.8
Above-ground (%)
3.33
5.83
5.83
0.83
5
0.83
0
0
0.8
0.83
Above-ground latrines are constructed where the water table is high since deep pit latrines could not be
dug. These latrines are built with stance on four walls that form the receptacle for human waste. Most
protected springs in the high-density residential areas were located in swamps. The above-ground pit
latrines had holes behind them, which were opened during the rainy season to release human waste into
drainage channels. This could have contributed to the contamination of protected springs. Although
there was treated piped water in the area, most respondents collected water from the protected springs
(91%). It is important to note that 90% of the respondents said that there was no solid waste disposal
site in the area, which greatly tallied with the 88% of respondents who said that they threw garbage in
the bush. Contamination of protected springs occurs when leachates from solid wastes get into water
bodies through runoffs.
12
Of the total number of respondents, only 23% kept animals (mainly cattle and goats). Rearing of
animals occurred mainly in the low-density residential areas (19.17% of respondents) as compared to
only 4% of respondents in the high-density residential areas. Although a lot of respondents said that
they suffered from malaria, a big percentage of respondents from high-density settlement areas suffered
from both malaria and diarrhoeal diseases.
DISCUSSION
Concerns over the quality of protected spring water have been confirmed by chemical and biological
analysis of water samples taken from protected springs located in both low and high-density settlement
areas at selected sites in Kampala City. Values exceeding the Uganda National Bureau of Standards
for drinking water quality and the National Guidelines for Rural Drinking Water Quality were
common. Therefore the water sources are not suitable for human consumption based on drinking water
standards.
The analysis has revealed contamination with ammonia, nitrates, thermal-tolerant faecal coliforms and
faecal streptococci. Contamination levels were much higher in the protected springs located in the
high-density than in low-density settlement areas. Direct observations during the field visits revealed
several sources of pollutants around the protected springs. There were no upstream water diversion
ditches or fences surrounding the protected springs, which are some of the requirements when
constructing protected springs. Lack of water diversion ditches allowed polluted water to seep into the
soils directly upstream of protected springs, resulting in direct pollution of groundwater supplying the
protected springs. A lot of rubbish is thrown very near the protected springs so when it rains the runoff
carries with it leachates from the solid waste as reported by Haiping and Yamada, 1998. In many cases
gullies that carry wastewater run directly upstream of the protected springs.
Pollution (nitrate and ammonium) is also attributed to human wastes (faecal matter) from pit latrines in
the vicinity of the protected springs. The nearest pit latrine in the high-density area was located only
0.5 metres upstream of the protected spring. Additionally faecal contamination (coliforms and
13
streptococci) of the protected springs is attributed to poor animal husbandry practices in the lowdensity settlement areas. Rainfall has been demonstrated as a major factor in pollutant transport into
protected springs. Similar observations have been made in other African countries including Uganda
(Howard et al., 2003, Taylor, 1995).
The results showed that all protected springs both from the high and low-density settlement areas were
polluted and unfit for human consumption. This report considers the National Guidelines for Rural
Drinking Water Quality (50 faecal coliforms per 100 ml) to be unacceptable, because the presence of
high levels of faecal coliforms in water implies presence of high levels of pathogens as observed by
Byamukama, 1998. A big percentage of the respondents from high-density settlement areas suffered
from diarrhoeal diseases. Constant exposure to pathogens results in water-borne disease outbreaks and
continuous presence of infective microorganisms in the population leads to poor health and low
productivity.
Rural-urban migration, which has contributed to the development of the urban areas through provision
of needed labour and skills, has also increased the number of urban poor and growth of slums. There is
not enough space to construct toilets or dumping places. This has been compounded by the settlement
in wetlands and thus eroding the natural filtration processes. Wetlands are used as dumping grounds,
which complicates the matter because they are water sources and this is where the protected springs are
located. The water table is high close to wetlands so here people cannot dig deep pit latrines and aboveground latrines are commonly constructed. The above-ground pit latrines have trap doors behind them,
which are opened during the rain season to release sewage and this has greatly contributed to the
contamination of protected springs.
CONCLUSIONS
Pollution of protected springs was closely linked with high-density settlement areas. This is attributed
to poor solid and liquid waste management practices. The presence of pit latrines near the protected
springs appeared to be very significant as sources of faecal material and nitrates. In addition, animal
husbandry practices in the vicinity of protected springs were sources of pollutants as a result of poor
14
management of animal wastes. Lack of urban planning has lead to settlement in wetlands as a result of
land pressure. The wetlands are used as dumping grounds, which has complicated the matter because
they are also water sources feeding springs. The increase in urbanisation of Kampala City will continue
to pause a threat to the quality of protected springs.
The threat can be addressed by strengthening physical planning of urban areas in Uganda to enable
adequate service provisions, revision of the Public Health Act of 1964 to address contemporary issues
and strengthen the implementation of public health and sanitation laws in urban areas.
Acknowledgements
The authors wish to thank the management and staff of the Wetlands and Water Research Laboratory at
Makerere University Institute of Environment & Natural Resources for the assistance rendered during
sample collection and analysis.
References
APHA, 1992. Standard methods for examination water and wastewater 18th Edition. Washington D. C.
Anon, J. 1996. World Water Environmental Engineering. Cambridge university press, Cambridge.
Byamukama, D. 1998. Faecal Pollution in Nakivubo Channel, Uganda: Comparison of Indicator
Organisms and Isolation Methods. M Sc. Thesis DEW 058.IHE Delf, The Netherlands.
Chapman, D. 1996. Water Quality Assessment: A Guide to the Use of Biota Sediments in
Environmental Monitoring. UNESCO / WHO / UNEP, Chapman Hall, United kingdom.
Haiping, Z. Yamada, K. 1998. Simulation of non-point source pollutant loading from urban area during
rainfall: An application of a physically based distribution model. Wat. Sci. & Technol 38 (10):
199-206.
15
Howard G., Teuton, J., Luyima P., Odongo, R. 2000. Water usage patterns in low-income urban
communities in Uganda;implications for surveillance. Int J Environ Health Res. 12(1):63-73.
Howard G., Pedley, S., Barett M., Nalubega M., Johal, K. 2003. Risk Factors contributing to
microbiological contamination of shallow groundwater in Kampala, Uganda. Wat.
Res.
37(14): 3421-3429.
Nasinyama G.W., McEwen S.A., Wilson J., Walter-toews D., Gyles C.L., Opuda-Asibo J. 2000. Risk
factors for acute diarrhoea among inhabitants of Kampala District, Uganda. South Afr. Med. J.
90(9):891-8.
State of Environment Report for Uganda 2000. National Environment Management Authority.
Taylor R.G., and K.W.F.Howard (1995). Averting shallow-well contamination in Uganda. 21st WEDC
Conference. Kampala, Uganda . pp 62-65.
Uganda Population Census (1992). The 1991 Population and Housing Census, Kampala District.
Statistics department, Ministry of Finance and Economic Planning, Entebbe, Uganda.
Van Ryneveld and M.B.,Fourie A.B,1997. A strategy for evaluating the environmental impact of onsite sanitation systems. Water SA; 23 (4):279-91
WHO,1996. Guidelines for drinking water quality, vol 2: health and supporting criteria, 2nd ed
Geneva, Switzerland. World Health Organisation.
16