ArticlePDF Available

Analysis of Microbial Quality of Drinking Water in Njoro Sub-county, Kenya

Authors:

Abstract and Figures

Abstract Drinking water should be free of microbial pathogens so as to be regarded as potable water and safe for drinking. However, water is prone to fecal contaminants which are the sources of gastrointestinal illnesses. In Njoro Sub-county, river Njoro and rain water are the primary sources of water which also reduces during dry seasons. Other water sources include boreholes, dams, springs and wells while in other cases, the residents store water in household storage containers for future uses. In this study, various water sources and water stored in different containers in Njoro Sub-County was analyzed for its microbial quality. Various microbial parameters such as total viable colony counts (TVCC), total coliforms (TC) and fecal coliforms (FC) were evaluated by use of the culture methods. Most of the water sources were contaminated. TVCC ranged from 0.47 to 1.76 CFU/1mL in water sources and 0.48 to 2.04 CFU/1mL in domestic storage containers. TC was in the range of between 0.30 to 1.89 CFU/100mL in water sources and 0.59 to 2.47 CFU/100mL in domestic storage containers. The mean FC in water sources ranged from 0.10 to 1.68 CFU/100mL and from 0.81 CFU/100mL domestic storage containers. Therefore frequent water testing should be performed by water authorities as recommended by WHO. At households, the people should employ various water treatment methods and practice safe water handling so as to avoid gastrointestinal infections.
Content may be subject to copyright.
Journal of Environment Pollution and Human Health, 2017, Vol. 5, No. 1, 15-21
Available online at http://pubs.sciepub.com/jephh/5/1/3
©Science and Education Publishing
DOI:10.12691/jephh-5-1-3
Analysis of Microbial Quality of Drinking Water in
Njoro Sub-county, Kenya
Kirianki PR1,*, Othira JO1, Kiruki S2
1Department of Biochemistry and Molecular Biology, Egerton University, 536-21115, Njoro, Kenya
2Department of Physical sciences, Chuka University, 109-60400, Chuka, Kenya
*Corresponding author: philipkirianki@gmail.com
Abstract Drinking water should be free of microbial pathogens so as to be regarded as potable water and safe for
drinking. However, water is prone to fecal contaminants which are the sources of gastrointestinal illnesses. In Njoro
Sub-county, river Njoro and rain water are the primary sources of water which also reduces during dry seasons.
Other water sources include boreholes, dams, springs and wells while in other cases, the residents store water in
household storage containers for future uses. In this study, various water sources and water stored in different
containers in Njoro Sub-County was analyzed for its microbial quality. Various microbial parameters such as total
viable colony counts (TVCC), total coliforms (TC) and fecal coliforms (FC) were evaluated by use of the culture
methods. Most of the water sources were contaminated. TVCC ranged from 0.47 to 1.76 CFU/1mL in water sources
and 0.48 to 2.04 CFU/1mL in domestic storage containers. TC was in the range of between 0.30 to 1.89
CFU/100mL in water sources and 0.59 to 2.47 CFU/100mL in domestic storage containers. The mean FC in water
sources ranged from 0.10 to 1.68 CFU/100mL and from 0.81 CFU/100mL domestic storage containers. Therefore
frequent water testing should be performed by water authorities as recommended by WHO. At households, the
people should employ various water treatment methods and practice safe water handling so as to avoid
gastrointestinal infections.
Keywords: coliforms, water quality, contamination
Cite This Article: Kirianki PR, Othira JO, and Kiruki S, Analysis of Microbial Quality of Drinking Water in
Njoro Sub-county, Kenya.” Journal of Environment Pollution and Human Health, vol. 5, no. 1 (2017): 15-21.
doi: 10.12691/jephh-5-1-3.
1. Introduction
Microbiological quality of water is measured by the use
of indicator organisms such as TVCC, TC and FC bacteria
[1]. TVCC are also known as total plate count, heterotrophic
plate count or pour plate and are widely used in the
measurements of heterotrophic microorganisms in water
meant for drinking purposes. The heterotrophs consist of
microorganisms such as yeasts, molds, and bacteria which
needs external sources of organic carbon in order to grow.
Some members of this group are opportunistic pathogens
and can cause aesthetic and non-life-threatening diseases
especially in immunosuppressed people as well as
children [1,2].
TVCC therefore, accesses the formation of colonies on
a culture media and hence it is a measure of the overall
bacteriological quality of drinking water in both public as
well as private water systems. The level or recoverability
of heterotrophic organisms using this method depends on the
type of media used, the culture temperatures, age of the
water sample and the duration of the culture. As a result,
high numbers of TVCC bacteria in a distribution system
might be a result re-growth of bacteria that resisted
treatment or alternatively those that were injured during
treatment have recovered. In this case, bacterial re-growth
can lead to devastating effects such as corrosion of pipes
and increased growth of slime and hence the need for
disinfectants [3].
TC comprises of bacterial species of fecal origin as well
as other non-fecal bacteria groups [4]. These microorganisms
are indicative of the general hygienic quality of the water
and potential risk of infectious diseases from the water.
Since it is not economical and practical to test for each
and every microorganism, the TC indicator tests are done
because their presence indicates the presence of pathogenic
groups of bacteria. Coliform bacteria should not be
detected in treated water supplies and, if found, suggest
inadequate treatment, post-treatment contamination, or
excessive nutrients. Thus tests for TC bacteria serves as an
indicator of both treatment efficiency and integrity of the
distributing system [5].
FC bacteria are associated with intestinal tract and
hence are released to the environment by fecal contamination
by animals as well as human fecal excreta [6]. They are
not necessarily pathogenic but their presence is indicative
of the presence of pathogenic bacteria of fecal origin.
They can enter water bodies through direct release of
waste from animals and untreated human sewage [7].
Additionally, agricultural activities like the application of
manure allow animal wastes to wash into water bodies [8].
When people consume fecally contaminated water, they
stand high chances of suffering from gastroenteric
16 Journal of Environment Pollution and Human Health
infections such as diarrhea. Children under the age of 5
years and the immunosupressed are the major victims of
diarrhea. This calls for the frequent monitoring of the
drinking water sources for their microbial quality [9]. In a
study that investigated the contamination chain of
domestic water in the Njoro Township in Kenya [10], the
E. coli (a fecal coliform) density was in the range of 0
220CFU/100 mL (point of collection) and 0520CFU/100
mL (low-income households and vendors). No previous
studies on water quality have been done in Mauche,
Maunarok and Kihingo locations prior to this study.
However, a study had been carried out on the fluoride
contamination of water in Lare location [11]. More studies
in Njoro location have been done on the microbial quality
of river Njoro both upstream and downstream and found a
high level of microbial contamination [9]. A different
study in Njoro Township (Njoro location) was aimed at
determining the microbial quality of drinking water
between the high income and low income households [10].
Therefore, this study is a conclusive and more informative
study on the microbial quality of drinking water in Njoro
Sub County.
Since no water quality studies have previously been
documented in Mauche, Kihingo and Maunarok locations,
this study sought to determine the overall microbial
quality of drinking water in Njoro Sub County. Previous
studies in Lare location were based on the fluoride levels
while most studies in Njoro location have mainly focused
on river Njoro. This study, therefore, sought to determine
the microbial quality of drinking water from various
sources and water stored inside various household storage
containers within the five locations in Njoro Sub-County.
2. Materials and Methods
Study area
Njoro Sub-county is located at an elevation of 1 600 to
2 000m above sea level and about 20km Southwest of
Nakuru town in the Kenyan Rift Valley Province. The
region is classified as semi-arid with a total annual rainfall
that ranges from 500mm in the lowlands to 1,800mm in
the highlands and occurring in two seasons namely the
long rains from March to April and the short rains from
October to December. The Njoro River and rain water are
the major sources of water but its volume reduces during
dry seasons. Thus other common sources of water in this
area include boreholes, wells, dams and springs. The
inconsistency in water supply in dry seasons in this area
also requires that people store water in household
containers for future use. The Sub-County is divided into
5 administrative locations namely: Njoro, Lare, Kihingo,
Maunarok and Mauche (Figure 1) with a total population
of 188,124 people. The mainstay of the economy in this
area is agri-based industries including vegetable and milk
processing, large-scale maize, wheat and barley farming
and light manufacturing industries such as timber milling,
canning, and quarrying.
Figure 1. Map of study area
Journal of Environment Pollution and Human Health 17
Sample collection
Simple random sampling was used to select the
participating villages and water was collected. The
samples were collected by visiting the homesteads at
random and taking a sample from any domestic container
that had stored water. The water from sources was
collected from any source that the researchers came across
within the 5 locations of the study area. Sterile 500mL
plastic bottles were used for sample collection. The
sample bottle was rinsed with the water sample three
times before taking the sample. Each of the samples was
replicated three times during sample collection. Water
samples from five locations of Njoro Sub-County were
collected from the river Njoro, springs, water vendor
kiosks, household storage containers, taps, wells and
boreholes. Samples were collected directly into the sample
container and transported immediately on ice to the
Egerton University Limnology laboratory for further
analysis within 6 hours of sample collection.
Improved and unimproved water sources
An improved water source is a type of water source
which as a result of a construction or intervention programs,
is protected from external sources of contamination. In
this study, the encountered and sampled improved water
sources were storage tanks, piped water/taps, boreholes,
protected wells and protected springs. Unimproved water
sources are those that are not protected in any way from
external contaminants like fecal matter. In this study, the
common unimproved water sources that were found and
sampled were river Njoro, dams, unprotected wells and
unprotected springs.
Domestic/household storage containers
These are the containers that are used to store water
inside the houses for future use in domestic settings. This
form of storage is common in areas where water supply is
not constant and hence the sources are not quite reliable.
In this study therefore, all the containers such as jerry cans,
jugs, cups, sufurias, pots and so on that were found to
having water in them were sampled three times and the
sample classified as household storage container as shown
in the results tables.
Data analysis
All the data generated during this study were coded and
entered into MS Excel 2010 and imported into
SAS version 9.1 for analysis. The means and standard
errors were determined and recorded. One way Analysis
of Variance was carried out to test whether the differences
between the means were significant or not while the
level of significance was determined using the Least
Significant Design (LSD) at α=0.05. The coliform counts
were transformed to log 10 and the results presented in
tables.
2.1. Determination of TVCC in Drinking
Water
TVCC test was done using the standard pour plate
method according to the method of [12] (Figure 2A).
Briefly, 1mL of the water sample was aseptically
transferred into clearly marked sterile Petri dishes. A
volume of 15mL of sterile molten Plate Count Agar
(PCA) at room temperature was added to each of the
Petridishes and thoroughly swirled to facilitate sample
distribution in the media. The plates were then left to
solidify at room temperature, inverted upside down and
incubated for 24 hours at 37°C. The colonies were
recorded as colony forming units per ml (CFU/1mL).
2.2. Total Coliform Counts (TC)
TC was enumerated by membrane filtration technique
method (Stuart, Bibby scientific, UK). A sterile 0.45µm,
47mm membrane filter (Sartorius, Germany) was placed
on a filter funnel. A volume of 10mL of each water
sample was added to a membrane and the vacuum pump
turned on. After the water was passed through the filter, it
was maintained in the vacuum until all liquid had passed.
The filter was then transferred using a sterile forceps to a
50mm disposable Petri dish containing Eosin Methylene
Blue (EMB) agar. Each funnel was rinsed with 20mL
distilled water between each water sample. All Petri
dishes were incubated upside down in an incubator for 24
± 2 hours at 37°C. All samples were analyzed by counting
the blue and pink colonies under a colony counter
(Acculite, Fisher, USA) and recorded as CFU/100mL as
shown in Figure2B.
Figure 2. TC (A) and TVCC (B) colonies after incubation in EMB and PCA media respectively
18 Journal of Environment Pollution and Human Health
3. Results
The samples were randomly collected leading to
unequal sample sizes among the 5 locations in the study
area. As such, during sampling, some water sources were
not found or were absent in some locations and hence not
available for sampling. Moreover, some domestic storage
containers were absent or were not found to be having any
water during sampling and they were not sampled. The
results for the sources and storage containers that were
absent or were not having any stored water are indicated
as (-) in the tables since there was no data collected for
analysis. The results obtained in this study were compared
to the WHO recommended levels for drinking water
quality as indicated in the appendices section.
3.1. TVCC in Water Sources and Water in
Various Household Storage Containers
All the sampled water sources were contaminated with
TVCC which was in the range of log10 0.48±0.12
(unprotected wells in Njoro) to 1.76±0.05 CFU/1mL (taps
in Maunarok and boreholes in Mauche) as shown in Table 1.
In the sampled household storage containers, the highest
log10 mean of TVCC CFU/1mL were recorded in buckets
used to store drinking water in Lare (2.04±0.01
CFU/100mL) while lowest means were in sufuria in
Mauche (0.48±0.09 CFU/100 mL) as indicated in Table 2.
3.2. TC Counts in Water Sources and Water
in various Household Storage Containers
All the sampled water sources in Njoro Sub-County
were contaminated with TC as shown in Table 3. The
mean log10 TC CFU/100 mL in the water sources were
highest in tanks in Mauche (2.12±0.27 CFU/100 mL) and
lowest in taps in Mauche (0.30±0.00 CFU/100 mL) and in
unprotected wells in Njoro (0.30±0.07 CFU/100mL). All
the sampled household containers were contaminated with
TC which ranged from log10 0.59±0.09 CFU/100mL (jerry
cans in Njoro) to 2.47±0.23 CFU/100mL (buckets in Lare)
as shown in Table 4.
Table 1. Mean log10TVCC CFU/1mL for water source types in Njoro Sub-County
WATER
SOURCE
KIHINGO
mean±SE
(n = number of
samples)
LARE
mean±SE
(n = number of
samples)
MAUCHE
mean±SE
(n = number of
samples)
MAUNAROK
mean±SE
(n = number
of samples)
NJORO
mean±SE
(n = number of
samples)
Unimproved sources
River - - - -
1.18±0.03a
(n=3)
Springs - - - - -
Wells - - - - 0.48±0.12
a
(n=3)
Dams - - - - -
Improved sources
Springs - - - - -
Taps/piped water -
1.14±0.18a
(n=9)
0.70±0.14a
(n=3)
1.76±0.05a
(n=3)
1.06±0.16a
(n=12)
Tanks
1.20±0.18a
(n=9)
0.63±0.15a
(n=6)
0.94±0.29a
(n=9)
1.31±0.14a
(n=15) -
Boreholes
0.69±0.14a
(n=6) -
0.48±0.13a
(n=3) - -
Wells 1.47±0.11
a
(n=6) - - - -
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
Table 2. Mean log10 TVCC CFU/1mL for domestic containers in Njoro Sub-County
WATER
CONTAINER
KIHINGO
mean±SE
(n = number
LARE
mean±SE
(n = number of
samples)
MAUCHE
mean±SE
(n = number
of samples)
MAUNAROK
mean±SE
(n = number of
samples)
NJORO
mean±SE
(n = number of
samples)
Gallons
- - - -
Jugs - -
1.08±0.14
(n=3) - -
Cups - - - - -
Jerry cans -
1.07±0.17a
(n=6) -
1.20±0.30
(n=6)
0.93±0.08
(n=6)
Clay pots - -
1.40±0.11
(n=3)
- -
Buckets -
2.04±0.01a
(n=3)
- - -
Sufurias - -
0.48±0.09
(n=3)
- -
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
Journal of Environment Pollution and Human Health 19
Table 3. Mean log10 TC counts/100mL for water source types in Njoro Sub-County
WATER
SOURCE
KIHINGO
mean±SE
(n = number
of samples)
LARE
mean±SE
(n = number
of samples)
MAUCHE
mean±SE
(n = number
of samples)
MAUNAROK
mean±SE
(n = number
of samples)
NJORO
mean±SE
(n = number
of samples)
Unimproved sources
River - - - -
1.40±0.03a
(n=3)
Springs - - - - -
Wells - - - - 0.30±0.02
a
(n=3)
Dams - - - - -
Improved sources
Springs - - - - -
Taps/piped water -
1.59±0.50a
(n=9)
0.30±0.07a
(n=3)
1.64±0.49a
(n=3)
0.90±0.22a
(n=12)
Tanks
1.87±0.03a
(n=9)
1.56±0.11a
(n=6)
2.12±0.27a
(n=9)
1.73±0.13a
(n=15) -
Boreholes
1.11±0.41a
(n=6)
-
0.60±0.21a
(n=3)
- -
Wells
1.89±0.08a
(n=6)
- - - -
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
Table 4. Mean log10 TC CFU/100mL for domestic containers in Njoro Sub-County
WATER
CONTAINER
KIHINGO
mean±SE
(n = number of
samples)
LARE
mean±SE
(n = number of
samples)
MAUCHE
mean±SE
(n = number of
samples)
MAUNAROK
mean±SE
(n = number
of samples)
NJORO
mean±SE
(n = number
of samples)
Gallons
0.95±0.31
(n=3) - - - -
Jugs - -
2.09±0.21
(n=3) - -
Cups - - - - -
Jerry cans -
1.42±0.27a
(n=6) -
1.76±0.18
(n=6)
0.59±0.09
(n=6)
Clay pots - -
2.09±0.39
(n=3) - -
Buckets - 2.47±0.23
a
(n=3) - - -
Sufurias - - 1.74±0.08
(n=3) - -
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
Table 5. Mean log10 FC CFU/100mL for water source types in Njoro Sub-County
WATERSOURCE
KIHINGO
mean±SE
(n = number
of samples)
LARE
mean±SE
(n = number
of samples)
MAUCHE
mean±SE
(n = number
of samples)
MAUNAROK
mean±SE
(n = number
of samples)
NJORO
mean±SE
(n = number
of samples)
Unimproved
sources
River - - - -
0.00±0.00a
(n=1)
Springs - - - - -
Wells - - - -
0.00±0.00a
(n=3)
Dams - - - - -
Improved sources
Springs - - - - -
Taps/piped water -
1.08±0.12a
(n=9)
0.00±0.00a
(n=3)
1.43±0.05a
(n=3)
0.00±0.00a
(n=12)
Tanks
0.10±0.02b
(n=9)
0.64±0.11a
(n=6)
0.00±0.00a
(n=9)
0.97±0.28a
(n=15)
-
Boreholes
0.00±0.00b
(n=6)
-
0.00±0.00a
(n=3)
- -
Wells
1.68±0.07a
(n=6)
- - - -
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
20 Journal of Environment Pollution and Human Health
Table 6. Mean log10 FC CFU/100mL for domestic storage containers in Njoro Sub-County
WATER
CONTAINER
KIHINGO
mean±SE
(n = number
of samples)
LARE
mean±SE
(n = number
of samples)
MAUCHE
mean±SE
(n = number
of samples)
MAUNAROK
mean±SE
(n = number
of samples)
NJORO
mean±SE
(n = number
of samples)
Gallons
0.00±0.00
(n=3)
- - - -
Jugs - -
0.00±0.00a
(n=3)
- -
Cups
-
-
-
-
-
Jerry cans -
0.00±0.00a
(n=6)
-
0.81±0.25
(n=6)
0.00±0.00
(n=6)
Clay pots - -
0.00±0.00a
(n=3)
- -
Buckets -
0.00±0.00a
(n=3)
- - -
Sufurias - -
0.00±0.00a
(n=3)
-
SE = standard error - Not tested since no sample of that type was found for collection during sampling
Means followed by the same small letter in a column are not significantly different at 5% LSD.
3.3. FC Counts in Water Sources and Water
in Various Household Storage Containers
The mean log10 FC CFU/100mL of the sampled water
sources in Njoro Sub County is presented in Table 5
whereby the counts ranged from 0.00 to 1.68±0.07
CFU/100mL. In the sampled household containers, all the
containers had mean log10 FC counts of 0.00CFU/100mL
apart from jerry cans in Maunarok (0.81±0.25CFU/100mL)
respectively (Table 6).
4. Discussion
The results obtained for microbial quality in Njoro Sub-
county, indicated that the drinking water sources were
microbially contaminated. The high concentrations of
TVCC and TC were an indication of the load of
contamination in water otherwise meant for drinking
purposes. A similar study on microbial analysis of stored
and treated drinking water in Nakuru North Sub-county
found that 35% (189/540) of the water samples were
positive for TC (51.8%), E. coli (32.3%) and Salmonella
(15.9%) respectively [13]. This indicated that the water
from sources and storage household containers in Nakuru
North-sub-county did not meet the microbial quality
guidelines by WHO in order to qualify for drinking
purposes. Continuous changes in the water flow rate at
sources and domestic containers could be responsible for
the increased HPC due to increased microbial growth.
Based on the various tested parameters and the different
locations, there are sources and containers that were less
contaminated and hence recommended for use. However
generally, this study indicated that the clay pots, sufuria
and some jerry cans were safe for storage while the
protected wells, taps and boreholes were the
recommended sources of water since they recoded low to
no microbial counts.
The low in TVCC, TC and FC levels in household
storage containers as compared to sources was probably
due to the use of treatment methods such as boiling and
chlorination. A similar trend of decreased TC at
households was observed in a study to determine the
bacteriological quality of drinking water in Kibera slums
in Nairobi. This study found that 10% of outhouse waters
and a further deterioration of about 95% of household’s
storage containers were contaminated with fecal coliforms
[14]. On the other hand, an increase in the bacterial counts
at households as compared to the water sources might be
linked to further deterioration of drinking water with
fecally contaminated hands or objects. A study conducted
in Vietnam also found off-premises piped sources to
contain more fecal contamination than on-premises piped
sources, with evidence of similar stored water quality for
both source types [15]. Additionally, there is a possibility
of contamination of water by vendors or during
transportation from off premises to homesteads, during
storage as well as handling [10]
Microbial contamination in storage containers may be
due to lack of regular cleaning, defects on the pipe-lines or
contamination during distribution. The trends of storing
water for long in households can result to a possibility of
fecal contamination of maybe initially good-quality
drinking water. Such contamination can arise from
dipping of fecally contaminated hands or utensils in the
storage containers especially by children. This form of
contamination pathway at the household is independent of
pollution at the source because the source might be free
from contamination. These findings of this study are
similar to those of another study on the bacteriological
quality of drinking water sources in Njoro Division, which
indicated that the fecal coliform counts in the Njoro River
were higher than the WHO guidelines [10]. Another study
found that Njoro River was highly contaminated with
indicator bacteria E. coli [9]. Therefore the increased
concentration of TVCC, TC and FC is likely to result to
increased diarrheal episodes among the local communities.
The children, elderly and immunosuppressed people are
most affected from diarrhea due to low immunity. The
reports from Njoro Health Centre and Nakuru Provincial
General Hospital (NPGH) in Kenya indicate a high
prevalence of undiagnosed diarrhea which was closely
linked to consumption of pathogen-polluted waters [16].
One of the major causes of diarrheal diseases is
consumption of microbe contaminated drinking water.
These diarrheal diseases weakens the immune system
leading to higher risk of other diseases which present
themselves as opportunistic infections [12]. The results
obtained for microbial quality in Njoro Sub-County,
indicated that majority of the drinking water sources were
Journal of Environment Pollution and Human Health 21
contaminated. The high concentrations of TVCC and TC
were an indication of a load of contamination in water
otherwise meant for drinking purposes. A similar study on
microbial analysis of stored and treated drinking water in
Nakuru North Sub-County found that 35% (189/540) of
all the samples were positive for TC (51.8%), E. coli
(32.3%) and Salmonella (15.9%) respectively [13]. This
indicated that the water from sources and storage
household containers in Nakuru North-Sub-County did
not meet the microbial quality guidelines by WHO in
order to qualify for drinking purposes.
The decrease in TVCC, TC and FC levels in some
household storage containers as compared to sources was
probably due to the employment of treatment methods
such as boiling and chlorination. An increase in the
bacterial counts at households as compared to the water
sources might be linked to further deterioration of
drinking water with fecally contaminated hands or objects.
A study conducted in Vietnam also found off-premises
piped sources to contain more fecal contamination than
on-premises piped sources, with evidence of similarly
stored water quality for both source types [14].
Additionally, there is a possibility of contamination of
water by vendors or during transportation from off
premises to homesteads, during storage and handling [10].
5. Conclusion
The presence of TVCC, TC and FC in drinking water is
of great public health significance and may lead to the
onset of various enteric diseases. Being a fecal-oral
pathogen, there are other vehicles necessary for its
transmission for instance contaminated hands, foods, and
utensils. The untreated water sources and household stored
water used for drinking and other domestic purposes could
harbor other microbes which are potential threats to the
health of residents. This calls for urgent intervention
strategies by the government, the community and other
stakeholders to minimize the health risks associated with
consumption of contaminated water.
Competing Interest
The authors have no competing of interest.
References
[1] McFeters, G. A. (2013). Drinking water microbiology: progress and
recent developments. Springer Science and Business Media, pp. 4-6.
[2] Chowdhury, S. (2012). Heterotrophic bacteria in drinking water
distribution system: a review. Environmental monitoring and
assessment, 184(10), 6087-6137.
[3] Walter, S. (2009). Characterization of heterotrophic plate count
(HPC) bacteria from biofilm and bulk water samples from the
Potchefstroom drinking water distribution system/by S. Walter
(Doctoral dissertation, North-West University), pp. 2-4.
[4] An, Y. J., Kampbell, D. H., and Breidenbach, G. P. (2002).
Escherichia coli and total coliforms in water and sediments at lake
marinas. Environmental Pollution, 120(3), 771-778.
[5] Muhammad, N., Sinha, R., Krishnan, E. R., and Patterson, C. L.
(2009). Ceramic filter for small system drinking water treatment:
Evaluation of membrane pore Size and importance of integrity
monitoring. Journal of Environmental Engineering, 135(11),
1181-1191.
[6] Casanovas-Massana, A., and Blanch, A. R. (2013). Determination
of fecal contamination origin in reclaimed water open-air ponds
using biochemical fingerprinting of enterococci and fecal
coliforms. Environmental Science and Pollution Research, 20(5),
3003-3010.
[7] Djuikom, E., Njine, T., Nola, M., Sikati, V., and Jugnia, L. B.
(2006). Microbiological water quality of the Mfoundi River
watershed at Yaoundé, Cameroon, as inferred from indicator
bacteria of fecal contamination. Environmental Monitoring and
Assessment, 122(1-3), 171-183.
[8] Brennan, F. P., Grant, J., Botting, C. H., O'Flaherty, V., Richards,
K. G., and Abram, F. (2013). Insights into the low-temperature
adaptation and nutritional flexibility of a soil-persistent
Escherichia coli. FEMS Microbiology Ecology, 84(1), 75-85.
[9] Kiruki, S., Limo M, Njagi, M, and Okemo, P., (2011).
Bacteriological quality and diarrhoeagenic pathogens in River
Njoro and Nakuru Municipal water, Kenya. International Journal
for Biotechnology and Molecular Biology Research, 2 (9), 150-162.
[10] Macharia, P. W., Yillia, P. T., Muia, W. A., Byamukama, D., and
Kreuzinger, N. (2015). Microbial quality of domestic water:
following the contamination chain in a rural township in Kenya.
Journal of Water Sanitation and Hygiene for Development, 5(1),
39-49.
[11] Mavura, J. W., Nyangeri, E., Nyanchaga, and Tiffani B., (2003).
Fluoride contamination in Drinking water in the Rift Valley,
Kenya and evaluation of a locally manufactured defluoridation
Filter. Journal of Civil Engineering, JKUAT, 8, 79-88.
[12] Omondi, D. O., Wairimu, M. A., Aketch, W. L., William, S. A.,
Trick, C. G., & Creed, I. F. (2015). Faecal pollution and solar
purification of community water sources within Lake Naivasha
basin, Kenya. Journal of Water Sanitation and Hygiene for
Development, 5(2), 252-260.
[13] Nyamache, A. K., Maingi, J. M., and Waithaka, P. N. (2014).
Physical-chemical and microbiological analysis in treated, stored
and drinking water in Nakuru north, Kenya. International Journal
of Microbiology and Epidemiological Research, 2(4), 29-37.
[14] Chemuliti, J. K., Gathua, P. B., Kyule, M. M., and Njeruh, F. M.
(2002). Bacteriological qualities of indoor and out-door drinking
water in kabera sub-location of Nairobi, Kenya. East African
Medical Journal, 79(5), 271-273.
[15] Brown J, Hien VT, McMahan L, Jenkins MW, Thie L, Liang K,
Printy E, and Sobsey MD, (2013). Relative benefits of on-plot
water supply over other 'improved' sources in rural Vietnam, Open
Journal of Medical and International Health, 18, 65-74.
[16] Nakuru Provincial General Hospital, (2009). Nakuru provincial
general hospital annual laboratory report. Ministry of Health,
Government of Kenya, Nakuru, Kenya.
Appendix
Appendix 1: The WHO microbial quality guidelines for
drinking water.
parameter
Guideline
Total coliforms
0 CFU/100mL
Fecal coliforms
0 CFU/100mL
Total viable cell counts
Not specified
... The majority of people who suffer from diarrhea belong to immunosuppressed individuals and children under five. This necessitates regularly checking the microbiological quality of drinking water sources (Kirianki, 2017). Disinfectant of drinking water by chlorination for microbial control had been investigated extensively. ...
... According to (Al-Afify et al., 2019), total coliforms are bacteria which indicate whether there is human or animal waste in the water. This current value of station outlets(<1) agree with the result recorded (<1.1 CFUs/100 ml) by Abdel-Shafy (2018) and disagree with Ezzat et al. (2017) who reported that (120 -100×103 CFU∕ 100 ml) for water samples collected from plant inlets (River Nile), while TC bacteria in water samples collected from outlets (treatment station at Cairo) were undetectable and that determined (0.30 to 1.89CFU/100mL) in water sources in kenya by Kirianki (2017) and that reported (46.5×102±100 and < 1 TC/100 ml) by Hasballah et al. (2023) for raw and treated water, respectively. Al-Jaberi and Al-Abbawy (2023) detected (900 MPN/100ml) for raw water samples and 170 MPN/100 ml for treated water. ...
... Fecal coliforms are rod-shaped, gram-negative, facultative anaerobic bacteria that do not generate spores which are oxidase negative, able to grow in the presence of bile salts or comparable surface agents, and within 48 hours at 44±0.5ºC, they can create gas and acid from lactose (Doyle and Erickson, 2006). It was found that fecal coliform (<1 CFUs/100 ml) at all St outlets in all seasons was higher than that recorded (Nil) by Abdel-Shafy (2018) and disagree with that obtained (50 -40×10 3 CFU/100ml) for entries (River Nile) while in exits FC bacteria were undetectable by Ezzat et al. (2017), that measured (1.1 to 3.1 of intakes MPN-index/100 ml) by Osman et al. (2011), that determined (0.10 to 1.68 CFU/100mL) in source waterin kenya by Kirianki (2017) and that reported (23.5×102±57.7 and < 1 FC/100ml) for raw water of River Nile and treated water, respectively by Hasballah et al. (2023). Besides, Abou-Dobara et al. (2023) detected 70 CFU/100 ml in Bahr Mowees water in summer and 3 CFU/100 ml for treated water. ...
... The meta-analysis indicates that the odds of the bacteriological quality of drinking water were three times higher among those who did not treat water at the household level compared to those who treated water at the household level. This finding was in agreement with studies conducted in Ethiopia [64] and Kenya [65]. In other words, Household-level water treatment plays a crucial role in reducing total and fecal coliform contamination in drinking water. ...
... Drawing water using dipping methods was four times more likely to result in bacteriological contamination compared to other methods of drawing drinking water, which is consistent with previous studies done in different parts of Kenya [57,65]. This indicated that withdrawing drinking water using the dipping methods could increase the risk of bacteriological contamination. ...
Article
Full-text available
Introduction Drinking contaminated water is a significant cause of mortality and morbidity in Sub-Saharan Africa, where access to safe drinking water is limited. Although numerous studies have investigated the bacteriological quality of drinking water in Ethiopia, their findings have been inconsistent and varied, hindering the implementation of effective water quality monitoring. Moreover, there is a lack of nationwide assessment of the bacteriological quality of drinking water in Ethiopia. Therefore, this systematic review and meta-analysis aimed to determine the bacteriological quality of drinking water and its associated factors in Ethiopia. Methods An international electronic database, including PubMed, Science Direct, Global Health, CINAHL, African Journals Online, HINARI, and Google Scholar was employed to retrieve the relevant articles. The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA) guidelines. A random-effects model was used to estimate the pooled effect size, and the Egger regression model was employed using STATA 14 software to assess potential publication bias. Results A total of 26 studies involving 7,962 water samples met the eligibility criteria for meta-analysis. The pooled prevalence of at least one bacteriological contamination of drinking water was 52.26% (95%CI: 39.09–65.43), with extreme heterogeneity (I² = 99.7%; p-value < 0.001). The pooled prevalence of total and fecal coliform in drinking water was 49.55% (95% CI: 34.88–64.23) and 44.27% (95%CI: 34.36–54.19), respectively. 14.13% of the water source was at a very high sanitary risk level (unfit for drinking), with significant heterogeneity (I² = 94.1%, p< 0.001). The absence of household-level water treatment (OR = 3.3; 95%CI: 1.28–5.32) and drawing water using dipping methods (OR = 4.52; 95%CI: 1.71–7.34) were determinant factors for bacteriological contamination of drinking water. Conclusion We found that the bacteriological quality of drinking water did not comply with the World Health Organization and Ethiopia’s standard guidelines for drinking water, which call for urgent intervention. One out of seven water sources was at a high sanitary risk level, which could increase the risk of infectious disease in the country. The absence of household-level water treatment and drawing water using dipping was a significant factor in the bacteriological quality of drinking water. Based on these findings, the water supply and sewerage authority should prioritize regular monitoring of the bacteriological quality of drinking water.
... However, in the present study, as a result of greater concern with bacteria viability, we embraced the use of total viable coliform counts (TVCC) and total viable E. coli. Counts (TVEC), following Olowe et al. (2016) [18] and Kirianki et al. (2017) [11] . Results show that TVCC ranged from 6 to 22 MPN/100 ml with a mean of 14.6 ± 8.38 MPN/100 ml, indicating loadings higher than the WHO permissible limit of 1 MPN/100 ml. ...
... However, in the present study, as a result of greater concern with bacteria viability, we embraced the use of total viable coliform counts (TVCC) and total viable E. coli. Counts (TVEC), following Olowe et al. (2016) [18] and Kirianki et al. (2017) [11] . Results show that TVCC ranged from 6 to 22 MPN/100 ml with a mean of 14.6 ± 8.38 MPN/100 ml, indicating loadings higher than the WHO permissible limit of 1 MPN/100 ml. ...
Article
The need to meet the all-year round green vegetable demands of the ever-growing population, especially in the urban and peri-urban towns of Ondo State, has made dry-season irrigation inevitable. Moreover, dry-season green vegetable farming provides an opportunity for smallholder farmers to further extend their cropping season, increase productivity, and ultimately improve their earnings. Thus, the aim of the present study was to carry out an assessment of irrigation water quality for dry-season green vegetable (Amaranthus crentus L.) farming in Ondo State, Nigeria. Ten (10) water samples covering at least three (3) major towns/cities in each of the three senatorial districts were collected from different green vegetable farms across the state during the dry season. Thereafter, samples of water collected were taken to the laboratory for both physicochemical and microbial analyses. Mean values of physicochemical parameters such as pH (6.12), EC (338.8 µS/cm), turbidity (4.03 NTU), TSS (0.428 mg/L), TDS (169.4 mg/L), and BOD (2.141 mg/L) were within the permissible levels, while COD (154 mg/L) and total hardness (135.24 mg/L) were above the limits. Microbial analysis also showed that total viable coliform counts (TVCC) were higher than the recommended limit, while total viable E. coli counts (TVEC) fell below detectable levels. Therefore, it was concluded that the irrigation water used for dry-season green vegetable farming in Ondo State was relatively of good quality, which serves as an encouragement to both farmers and consumers of the vegetable. However, given the higher levels of total hardness and TVCC, continuous monitoring and assessment of irrigation water quality in the state, especially beyond the areas presently covered, and awareness campaigns against urban surface water pollution to prevent potential faecal contamination of the sources and avert possible ingestion of pathogenic organisms through the consumption of green vegetables are recommended.
... Water is needed in the body for digestion, translocation, absorption and excretion of metabolic wastes, secretion of hormones, enzymes and other biochemical body functions [2] . Nature is a great purifying system, water passes from the sky to the earth, from the earth to the streams, rivers, and to the sea, and then returns back to the sky [3] . But this natural process is breaking down in a global scale. ...
... Several studies have documented the detection of coilforms and heterotrophic bacteria in bottled and sachet water, which indicated that counts exceeded the international standards set for potable drinking water. Total coliform bacteria in water may cause health risk for infants, young children, the elderly and immunocompromised persons [8,3] . Although the presence of heterotrophic bacteria in drinking water is not an indication that the water presents health risks but it can pose significant risks in immunocompromised individuals. ...
Article
Full-text available
Microbiological examination of bottled and sachet water sold and consumed in Nnewi metropolis, Anambra State, Southeast Nigeria was carried out to assess their microbiological qualities. The bottled and sachet water were bought from various sales outlets in Nnewi, Nnobi, Ichi and Ozubulu towns. Overall 45 samples belonging to 15 different brands (5 bottled table and 10 sachet water) were analyzed for their microbiological quality using standard microbial methods in triplicates of each brand. The biochemical characteristics of the isolates were studied and results showed varied degrees of microbial load which indicated Pseudomonas spp., Klebsiella spp., Staphylococcus aureus, Bacillus spp., Salmonella spp., Enterobacter spp. and Citrobacter spp. Of all the 15 sachet water brands analyzed, 40 % failed to meet the WHO drinking water standard of ten coliform per 100 mL, making them unsuitable for human consumption, but all the bottled water samples were of potable quality. The bottled water samples had more microbiological quality than the sachet water samples. The contaminated sachet water samples are not fit for human consumption. Causes of contamination of the water samples and recommendations for improving their microbiological quality were highlighted.
... A study conducted in Kericho, Kenya showed that household practices such as drawing of water, hand-washing, storage type, human waste disposal, water treatment and general cleanliness were correlated with thermocolerant coliforms contamination (Too et al., 2016). Storage containers that require inserting of other smaller containers in order to obtain the water, have been found to cause a lot of contamination (Kirianki et al., 2017). The hygiene of the water handler and the cleanliness of the drawing container influences water quality as these may contain contaminants that could be introduced into the drinking water during fetching at both the source and at household level (Brown et al., 2013). ...
... This could be because the first category of containers involves dipping other smaller containers in order to obtain the drinking water. These smaller containers could contain contaminants introduced to them from the water handler or from the environment (Kirianki et al., 2017). ...
Article
Full-text available
Household drinking water quality is dependent on a number of determinants which could be arising at the source, during transportation or due to storage and handling practices. The challenge of unsafe water is even big in urban settings that are often characterized by exponential population growth, increased urbanization, industrialization and poor sanitary facilities. Contaminated water is a leading cause of water borne diseases which are a major public health and policy makers concern. In fact, Water borne diseases are third cause of mortality in Kenya whereas they are ranked second in Kisii. The study was designed to investigate the factors affecting household drinking water quality in Kisii Town that has four main zones which include: Mwembe, Jogoo, Nyanchwa and CBD. Demographics, level of awareness in terms of water quality as well as hygiene and sanitation practices of the study population were studied using questionnaires. The questionnaires were filled by interviewing household heads from 422 sampled households. Qualitative data was also obtained by use of Focused group discussions (FGDs). Perspectives of key people such as public health officers were acquired through Key informant interviews (KIIs). The study found a significant relationship between household size and water quality in terms of presence of total coliforms. The following hygiene and sanitation factors were found to be having significant relationship with presence of E. coli in household drinking water; source of water(p=0.002), transportation container (p=0.029), covering during transportation (p=0.012), storage container (p<0.001), method of drawing from storage container(p<0.001), feces disposal (p=0.001) and garbage disposal method (p=0.04). The conclusion of this study is that good hygiene and sanitation practices are important in ensuring total safety of drinking water at the point of use. There is therefore need for more capacity building in this region to ensure that people do not consume contaminated water which is a major contributing factor to water-borne diseases.
... Similar findings by who high coliform in the household water which they associated with poor water handling practices. 9,14 Borehole water samples collected at the household were contaminated with faecal coliforms more than tap water. The faecal coliforms exceeded the acceptable maximum limits, hence the borehole water that was stored in the HH was not suitable for consumption. ...
Article
Full-text available
Background: Globally, 45% of the global population, showing that the compliance level is very low in most developing countries. In Kenya, 10% of all deaths caused by waterborne illnesses are due to water scarcity and poor sanitation. Mombasa County is facing a major problem in the provision of domestic water to its residents, thus causing a water shortage.Methods: Descriptive cross-sectional study was conducted in Mombasa County between November 2020-March 2021. 55 water samples were randomly collected for analysis of microbial contamination. Using stata for analysis, t-test was calculated to determine the relationship with p<0.05.Results: TC mean for boreholes was ±761.68 CFU and tap water was ±712.23 CFU. There was a significant difference in means between the two groups for TC (t=7.38, df=41.94, p=0.000). Faecal coliforms (FC) for borehole and tap water was ±739.52 CFU and ±115.42 CFU respectively. FC showed a significant difference between the two groups (t=3.74, df=36.84 and p=0.0003). HPC means for borehole and tap water of water were ±7730.62 CFU and ±4092.12 CFU respectively. There was no significant difference in means for HPC for the two groups (t=1.73, df=53 and p=0.0445). 34.3% (n=12) and 20% (n=4) of boreholes and tap water were contaminated with salmonella respectively. None of the water samples collected had Shigella. Conclusions: All borehole water samples stored in the household storage containers were more contaminated than tap water, hence not fit to be consumed in the household.
... All the water samples were within the WHO acceptable range of less than 1000ppm. TDS affects the palatability of drinking water [25]. Electrical conductivity ranged from 27-136 μSCM À1 with a mean of 73.9028μSCM À1 . ...
Article
Full-text available
Water is a basic human need which is required in many operations especially in households. However, this essential commodity in most cases does not meet the generally accepted safety standards. The study was designed to investigate the physico-chemical and bacteriological quality of drinking water used in households in Kisii town, Kenya. Analytical cross-sectional study was conducted to obtain information concerning household drinking water quality and safety. Stratified random sampling was used to obtain 422 drinking water samples at the point of consumption from the 4 zones of Kisii town for analysis. From the study it was revealed that TDS and electrical conductivity of the analyzed water samples were within the recommended standards of less than 1000 ppm and 1500 μSCM⁻¹ respectively. Further, it was found that 69.4% of the samples had pH range of between 6.5-8.5, 91.9% had turbidity of less than 5NTU, 3.8% had temperature below 15 °C and 31.2% of the chlorinated samples had chlorine residue above 0.2 ppm. In terms of bacteriological analysis, 39.3% of the samples were contaminated with total coliforms and 17.5% with E. coli. The main finding from the study was that the household water samples were contaminated with bacteria and unfit for human consumption because both total coliforms and E. coli exceeded the recommended Kenya Bureau of Standards (KEBS) and WHO standards. Therefore, public health officers should not only collect water samples from sources but also from households regularly to ascertain its quality and provide water safety promotion education to the general public. There was a strong relationship between bacterial contamination and temperature as well as chlorine residue. The study recommends Gusii Water and Sanitation Company (GWASCO) whose treatment and distribution capacity is expected to increase 4.5 times the current capacity to improve on their chlorine dosage at the treatment plant to ensure a minimum chlorine residue of 0.2 ppm at the household and community taps.
Article
The study evaluated water access and disease prevalence in the Rhino Camp refugee settlement by mapping water sources, interviewing residents, and reviewing health centre records. Primary water sources were tanks providing 10.2 litres per person per day (l/p/d). Microbial contamination including total coliforms reaching 2.8 × 104 cfu/ml (household container – Tika), thermotolerant coliforms, and faecal enterococci were observed throughout the water supply chain, suggesting faecal contamination and posing a health risk. We attributed this to poor handling and storage related to poor sanitation in the settlement, highlighting the importance of promoting hygiene practices among refugees, particularly in the Ofua Zone, which had the highest contamination risks and the highest sanitary risk scores. Malaria and typhoid were the most prevalent diseases, with Ofua having the highest disease incidence. Water collection was mostly done by adult females and female children (34.7 and 30.3%, respectively) although water collection was generally low (<4 times a day). Boiling water was associated (p < 0.05) with the incidence of hepatitis A in Ofua. Adequate water (>20 l/p/d), water treatment, and education on hygiene practices especially for adult females are essential in lowering contamination and the incidence of diseases.
Article
Full-text available
Objective More than half of the 700 million people worldwide who lack access to a safe water supply live in sub-Saharan Africa, including Ethiopia. Globally, approximately 2 billion people use drinking water sources that are contaminated with fecal matter. However, little is known about the relationship between fecal coliforms and determinants in drinking water. Therefore, the objective of this study was to investigate the potential for contamination of drinking water and its associated factors in households with children under 5 years of age in Dessie Zuria district in northeastern Ethiopia. Methods The water laboratory was conducted based on the American Public Health Association guidelines for water and wastewater assessment using a membrane filtration technique. A structured and pre-tested questionnaire was used to identify factors associated with the potential for contamination of drinking water in 412 selected households. A binary logistic regression analysis was performed to determine the factors associated with the presence or absence of fecal coliforms in drinking water, with a 95% confidence interval (CI) and a value of p ≤ 0.05. The overall goodness of the model was tested using the Hosmer-Lemeshow test, and the model was fit. Results A total of 241 (58.5%) households relied on unimproved water supply sources. In addition, approximately two-thirds 272 (66.0%) of the household water samples were positive for fecal coliform bacteria. Water storage duration ≥3 days (AOR = 4.632; 95% CI: 1.529–14.034), dipping method of water withdrawal from a water storage tank (AOR = 4.377; 95% CI: 1.382–7.171), uncovered water storage tank at control (AOR = 5.700; 95% CI: 2.017–31.189), lack of home-based water treatment (AOR = 4.822; 95% CI: 1.730–13.442), and unsafe household liquid waste disposal methods (AOR = 3.066; 95% CI: 1.706–8.735) were factors significantly associated with the presence of fecal contamination in drinking water. Conclusion Fecal contamination of water was high. The duration of water storage, the method of water withdrawal from the storage container, covering of the water storage container, the presence of home-based water treatment, and the method of liquid waste disposal were factors for fecal contamination in drinking water. Therefore, health professionals should continuously educate the public on proper water use and water quality assessment.
Chapter
With an increasing global population in developed and developing countries, one of the biggest challenges is to provide a continuous supply of chemically and biologically stable potable water supply in megacities of different nations. However, rapid anthropogenic activities affect the overall quality of potable water. Unplanned disposal practices regarding wastes including pharmaceuticals, foodstuff additives, lubricants, synthetic resins, disinfectants, heavy metals, microplastics, microbial pathogens, and organic contaminants have negatively impacted the drinking water quality and supply system in megacities of developed and developing countries. In water management plants, drinking water remains in an almost sterile environment before distribution through the water supply in megacities. However, maintenance for biological and chemical stability of the drinking water during supply chain is a very challenging concern predominantly for developing countries compared to developed countries. This is due to several reasons, including poor water purification management platforms, drinking water supply, physicochemical nature of drinking water, and abundance of contaminants in drinking water. Therefore, improper management of water resources and water supply systems is a major alarming issue which enhances morbidity and mortality rates, as indicated by deadly diseases around the world related to improper sanitation. Thus, the main aim of this study is to provide a comparative overview of water supply systems in developing and developed countries. Moreover, the current study illustrates the impact of contaminants on water quality, advances in water purification-recycling processes, and the effects of microbial community dynamics to ensure the quality of water and its corresponding proper supply to megacities in developed and developing countries as a sustainable way forward.
Article
Full-text available
As in other parts of Africa, and in other developing nations, the rise in the human population and anthropogenic activities within the Lake Naivasha basin is causing an increase in human health risks due to faecal contamination of domestic water sources. This study investigated faecal pollution of community water sources within the Lake Naivasha basin by measuring the densities of total coliforms, Escherichia coli, intestinal enterococci, Clostridium perfringens and heterotrophic bacteria in Lake Naivasha, the Malewa and Gilgil Rivers, and boreholes using membrane filtration techniques and heterotrophic plate count procedures. Selected physico-chemical parameters were also measured in situ from all the water sources sampled. Lakes and rivers had significantly higher microbial abundances than boreholes. Unlike boreholes, surface sources (rivers and lake) showed significant variation with respect to sampling sites for all the microbiological parameters (P< 0.05). The use of solar radiation in water disinfection with temperatures of 75 WC after 30 minutes from pasteurization point (time zero) fully eradicated E. coli and total coliforms from all the water sources. In conclusion, there is faecal pollution in water sources used by communities within the Lake Naivasha basin. The use of solar radiation is therefore recommended for water purification to reduce likely incidences of waterborne diseases.
Article
Full-text available
The microbiological quality of drinking water in municipal water distribution systems (WDS) depends on several factors. Free residual chlorine and/or chloramines are typically used to minimize bacterial recontamination and/or regrowth in WDS. Despite such preventive measures, regrowth of heterotrophic (HPC) and opportunistic bacteria in bulk water and biofilms has yet to be controlled completely. No approach has shown complete success in eliminating biofilms or HPC bacteria from bulk water and pipe surfaces. Biofilms can provide shelter for pathogenic bacteria and protect these bacteria from disinfectants. Some HPC bacteria may be associated with aesthetic and non-life threatening diseases. Research to date has achieved important success in understanding occurrence and regrowth of bacteria in bulk water and biofilms in WDS. To achieve comprehensive understanding and to provide efficient control against bacteria regrowth, future research on bacteria regrowth dynamics and their implications is warranted. In this study, a review was performed on the literature published in this area. The findings and limitations of these papers are summarized. Occurrences of bacteria in WDS, factors affecting bacteria regrowth in bulk water and biofilms, bacteria control strategies, sources of nutrients, human health risks from bacterial exposure, modelling of bacteria regrowth and methods of bacteria sampling and detection and quantification are investigated. Advances to date are noted, and future research needs are identified. Finally, research directions are proposed to effectively control HPC and opportunistic bacteria in bulk water and biofilms in WDS.
Book
The microbiology of drinking water remains an important worldwide concern despite modem progress in science and engineering. Countries that are more technologically advanced have experienced a significant reduction in water­ borne morbidity within the last 100 years: This reduction has been achieved through the application of effective technologies for the treatment, disinfec­ tion, and distribution of potable water. However, morbidity resulting from the ingestion of contaminated water persists globally, and the available ep­ idemiological evidence (Waterborne Diseases in the United States, G. F. Craun, ed. , 1986, CRC Press) demonstrates a dramatic increase in the number of waterborne outbreaks and individual cases within the United States since the mid-1960s. In addition, it should also be noted that the incidence of water­ borne outbreaks of unknown etiology and those caused by "new" pathogens, such as Campylobaeter sp. , is also increasing in the United States. Although it might be debated whether these increases are real or an artifact resulting from more efficient reporting, it is clear that waterborne morbidity cannot be ignored in the industrialized world. More significantly, it represents one of the most important causes of illness within developing countries. Approxi­ mately one-half the world's population experiences diseases that are the direct consequence of drinking polluted water. Such illnesses are the primary cause of infant mortality in many Third World countries.
Article
A study was undertaken in Njoro Township, Kenya to evaluate the extent to which drinking water was subjected to post-collection faecal contamination in low-income and high-income households. Boreholes were the main drinking water sources, accounting for roughly 70% singular access. The microbial quality of drinking water from the boreholes deteriorated from the point-of-collection through conveying containers of small-scale water vendors to household storage containers, irrespective of their income status. The densities of Escherichia coli (EC) were relatively low at the point-of-collection – median (M): 18 CFU/100 mL, range (R): 0–220, n ¼ 60 – increasing considerably in the containers of water vendors (M: 290 CFU/100 mL, R: 30–350) and slightly (M: 360 CFU/100 mL, R: 0–520) between vendors and low-income households, many of whom used the services of vendors unlike high-income households who relied on a piped system on premises (M: 40 CFU/100 mL, R: 0– 500). Post-collection contamination was high in low-income households compared to high-income households but differences were not significant between the two household categories with and without household water treatment (HWT). Different HWT methods in the two household categories significantly reduced faecal contamination, but unhygienic handling and poor storage practices afterwards caused recontamination. HWT and behavioural change measures need not selectively target household groups solely on the basis of their income status.
Article
A survey of the amount of Fluoride in ground, potable water in Njoro division, Nakuru district and some parts outside the division was conducted to determine the concentration of Fluoride the residents are consuming through water. This area is situated in the Great Rift Valley of East Africa, which is known to have high levels of the anion in the water due to the volcanic eruptions that occurred thousands of years ago. Water samples were collected from 18 sources and analysis was performed using an ion selective electrode (ISE). Concentration levels ranged from 0.78 mg/L (river water) to 11 mg/L (borehole water). A locally manufactured de-fluoridizer made of charred bone particles was evaluated for its ability to remove F- from water. Generally, more than 99% F- was removed by the de-fluoridizer. Apart from removing the target anion, F-, some metal cations are also removed at various extents, while others are added into the water apparently from the bone char through leaching. (Journal of Civil Engineering, JKUAT: 2002 8: 79-88)
Article
Ceramic filtration has recently been identified as a promising technology for drinking water treatment in households and small communities. This paper summarizes the results of a pilot-scale study conducted at the U.S. Environmental Protection Agency's (EPA) Test & Evaluation (T&E) Facility in Cincinnati on two ceramic filtration cartridges with pore sizes of 0.05 and 0.01 μm to evaluate their ability to remove turbidity and microbiological contaminants such as bacteria [Bacillus subtilis (≈1.0 μm) and Escherichia coli (≈1.4 μm)], Cryptosporidium oocysts (4-6 μm), polystyrene latex (PSL) beads (2.85 μm) (a surrogate for Cryptosporidium), and MS2 bacteriophage (≈0.02 μm) (a surrogate for enteric viruses). The results demonstrated that the relatively tighter 0.01-μm cartridge performed better than the 0.05-μm cartridge in removing all the biological contaminants and surrogates. For turbidity removal, the 0.01-μm cartridge performed slightly better than the 0.05-μm cartridge; however, the permeate rate in the 0.01-μm cartridge reduced rapidly at higher feed water turbidity levels indicating that a tighter membrane should only be used with adequate pretreatment or at a low feed water turbidity to prolong membrane life. Microbiological monitoring was identified as a more sensitive indirect integrity monitoring method than turbidity and particle count monitoring to ensure effective treatment of water by ceramic filtration. Both PSL beads and B. subtilis showed potential as effective surrogates for Cryptosporidium, with B. subtilis showing higher degree of conservatism. Any opinions expressed in this article are those of the writer(s) and do not necessarily reflect the official positions and policies of the EPA. Any mention of products or trade names does not constitute recommendation for use by EPA. This document has been reviewed in accordance with EPA's peer and administrative review policies and approved for publication.
Article
An understanding of the survival capacity of Escherichia coli in soil is critical for the evaluation of its role as a faecal indicator. Recent reports that E. coli can become long-term residents in maritime temperate soils have raised the question of how the organism survives and competes for niche space in the sub-optimal soil environment. The ability of an environmental isolate to utilise 380 substrates was assessed together with that of a reference laboratory strain (E. coli K12) at both 15°C and 37°C. At 15°C, the environmental strain could utilise 161 substrates with only 67 utilisable by the reference strain, while at 37°C, 239 and 223 substrates could be utilised by each strain, respectively. An investigation into the cold response of the strains revealed that E. coli K12 was found to reduce the expression of biosynthetic proteins at 15°C, while the environmental isolate seemed to switch on proteins involved in stress response, suggesting low temperature adaptation in the latter. Taken together the results indicate that the environmentally persistent E. coli strain is well adapted to use a wide range of nutrient sources at 15°C and to direct its protein expression to maintain a relatively fast growth rate at low temperature. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Article
Objective: Access to improved water sources is rapidly expanding in rural central Vietnam. We examined one NGO-led piped water supply programme to assess the drinking water quality and health impacts of piped water systems where access to 'improved' water sources is already good. Methods: This longitudinal, prospective cohort study followed 300 households in seven project areas in Da Nang province, Vietnam: 224 households who paid for an on-plot piped water connection and 76 control households from the same areas relying primarily on 'improved' water sources outside the home. The 4-month study was intended to measure the impact of the NGO-led water programmes on households' drinking water quality and health and to evaluate system performance. Results: We found that: (i) households connected to a piped water supply had consistently better drinking water quality than those relying on other sources, including 'improved' sources and (ii) connected households experienced less diarrhoea than households without a piped water connection (adjusted longitudinal prevalence ratio: 0.57 (95% CI 0.39-0.86, P = 0.006) and households using an 'improved' source not piped to the plot: (adjusted longitudinal prevalence ratio: 0.59 (95% CI 0.39-0.91, P = 0.018). Conclusions: Our results suggest that on-plot water service yields benefits over other sources that are considered 'improved' by the WHO/UNICEF Joint Monitoring Programme.
Article
Low levels of fecal indicator bacteria (FIB) were recently detected in two reclaimed water open-air ponds used to irrigate a golf course located in Northeastern Spain. The aim of this study was to evaluate the feasibility of a biochemical fingerprinting method to track the origin of fecal contamination in water with low FIB levels, as in the aforementioned ponds. We also aimed to determine whether FIB presence was due to regrowth of the reclaimed water populations or to a contribution of fecal matter whose source was in the golf facility. Three hundred and fifty enterococcal strains and 308 fecal coliform strains were isolated from the ponds and reclamation plant, and they were biochemically phenotyped. In addition, the inactivation of several microbial fecal pollution indicators (fecal coliforms, total bifidobacteria, sorbitol-fermenting bifidobacteria, somatic bacteriophages, and bacteriophages infecting Bacteroides thetaiotaomicron) was studied using a mesocosm in situ in order to obtain information about their decay rate. Although FIB concentration was low, the biochemical fingerprinting provided evidence that the origin of the fecal contamination in the ponds was not related to the reclaimed water. Biochemical fingerprinting thus proved to be a successful approach, since other microbial source-tracking methods perform poorly when dealing with low fecal load matrices. Furthermore, the mesocosm assays indicated that none of the microbial fecal indicators was able to regrow in the ponds. Finally, the study highlights the fact that reclaimed water may be recontaminated in open-air reservoirs, and therefore, its microbial quality should be monitored throughout its use.
Article
To compare the bacteriological quality of out-house (tank or standpipe) water and in-house drinking water (storage containers) and determine the risk factors influencing it. A cross-sectional study. The study was carried out in Kibera slums located 7 km southwest from the Nairobi City centre. Water samples from twenty outside tanks/standpipes and sixty from in-house water storage containers. Pour plate method was used to enumerate total bacterial counts in water, while the multiple tube technique was used to determine faecal coliform (FC) and faecal streptococci (FS) numbers. A questionnaire and environmental observation were used to determine the risk factors influencing bacteriological quality of water. The mean total bacterial counts (TBC) for out-house water was 46.6 per 100 ml while that for in-house water was 818.2 per 100 ml. Faecal coliforms were isolated from 7 (35%) standpipes and 57 (95%) in-house storage containers. The mean faecal coliform count was 93 and 103.4 per 100 ml for out-house and in-house water, respectively. The counts were significantly higher in the latter. Faecal streptococci were isolated from 2 (10%) standpipes and 37 (61.7%) in-house storage containers. The mean faecal streptococci counts were 35 and 65 per 100 ml for out-house and in-house water sources, respectively. Escherichia coli was isolated in 2 (10%) of out-house water and 30 (50%) of in-house. Of these, four were enteropathogenic, serotype 011 from one out-house water source and serotypes 011, 011, 0112ac from in-house water sources. Bacteriological contamination of water at the source with a further deterioration between the collection points and homes was observed. A defective water delivery system and inadequate environmental sanitation were a potential source of contamination for out-house water. Scoops were a major source of contamination for stored water.