Case study of_jar_water_in_kathmandu_valley-ranjana_budhathoki (1) BY Muhammad Fahad Ansari 12IEEM14
ANALYSIS OF THE PHYSICO-CHEMICAL
AND BACTERIOLOGICAL PARAMETERS OF BOTTLED WATER
AVAILABLE IN KATHMANDU VALLEY
A Case Study on the Partial Fulfillment of the Requirements for
M.Sc., First Year, Environment Science, T.U.
Central Department of Environment Science
M.Sc. 1st year
Symbol number- 4374
LETTER OF RECOMMENDATION
This is to certify that Ms. Ranjana Budhathoki, a student of M.Sc. 1st year, Central
Department of Environment Science, T.U., has carried out this case study entitled “Analysis
of Physico-chemical and Bacteriological Parameters of Bottled Water Available in
Kathmandu Valley” under my supervision and guidance.
She is a sincere student and has performed all the works in field as well as laboratory with
full dedication and satisfaction. So, I recommend this case study report for final approval.
Ms. Ushana Shrestha
Central Department of Environmental Science
This case study entitled “Analysis of Physico-chemical and Bacteriological Parameters of
Bottled Water Available in Kathmandu Valley” is a product of research, knowledge and
support of many individuals as well as organizations to whom I would like to express my
I am truly indebted to my supervisor Ms. Ushana Shrestha for her supervision, guidance and
invaluable suggestion. Her recommendations and suggestions have been a key for the
successful completion of my case study.
I would also like to express my gratitude to the concerned officials of Company Registrar’s
Office and Kathmandu Upatyaka Khanepani Limited (KUKL) for providing necessary
I am very much thankful to my classmates for their constant support, co-operation and
motivation throughout the study. I would also like to thank the lab staff for their ever ready
I would like to thank all other respected teachers of Central Department of Environmental
Science, Tribhuvan University, Kirtipur for their continuous aspiration and motivation.
Water is vital for life. However, it also serves as the commonest route of transmission of a
number of infectious diseases. The WHO has estimated that up to 80% of all sickness and
disease in the world is caused by inadequate sanitation and polluted water.
Nepal faces a number of problems regarding both its drinking water quality and availability.
The municipal water supplies are inconsistent and unreliable. Not only the shortages in
quantity, but also the compromised quality of municipal tap water has become a major public
health issue (Warner N.R. et al., 2007). Throughout Nepal, people are facing health problems
resulting from water contamination.
In the context of growing health consciousness and chronic water shortages, most of the
urban residents have switched to bottled water as a safe alternative. The public perception is
that bottled water is regularly of high quality. This belief is encouraged by publicly reported
problem of municipal tap water as well as the public perception of purity driven by
advertisements. However, many studies have shown that these beliefs need not always be
Samples of nine brands of jar water of 20 ml capacity were analyzed twice for various
physicochemical as well as bacteriological parameters during January, February and March.
All the physicochemical parameters like pH, DO, hardness, alkalinity, chloride were within
WHO acceptable limits. Ammonia was detected in some samples but is within the limits set
by WHO. Iron and Nitrates were found in small quantities but within the limits set by WHO.
From the bacteriological point of view, 66% of the total samples were heavily contaminated
with coliforms during the test in January/February. During the test in February/March, 89%
of the total sample was found to be contaminated with total coliforms whereas 66% were
contaminated with fecal coliforms. From the analysis of jar water marketed in Kathmandu
valley, it was concluded that the jar water samples are heavily contaminated with coliform
bacteria and unsatisfactory for drinking purpose.
Asian Development Bank
American Public Health Association
Beverage Marketing Corporation
Central Bureau of Statistics
Colony Forming Units
Italian International Co-operation
Ethylene Diamine Tetra Acetic Acid
Eosin Methylene Blue
Environment and Public Health Organization
Environment Protection Act
Food Act Regulation
Japan International Co-operation Agency
Kathmandu Upatyaka Khanepani Limited
Million Liters per day
Most Probable Number
Nepal Drinking Water Quality Standards
National Resources Defense Council
Percentage of Hydrogen Ion Concentration
United Nation Children Fund
World Health Organization
TABLE OF CONTENTS
Letter of Recommendation
Table of Contents
Lists of Tables
List of Figures
Chapter 1: Introduction
1.1.1. Fresh Water Shortage
1.1.2. Water Quality
1.1.3. Bottled Water
1.1.4. Water Related Problems in Nepal
1.1.5. Bottled Water in Nepal
1.2. Statement of the Problem
1.4.1. Broad Objective
1.4.2. Specific Objectives
Chapter 2: Literature Review
Chapter 3: Methodology
3.1. Sample collection, transportation and processing
3.2. Sampling frequency
3.3. Analysis of water samples
3.3.1. Analysis of physicochemical parameters of water samples
3.3.2. Analysis of microbial variables of water sample
Chapter 4: Results and Discussion
Chapter 5: Conclusion and Recommendations
LIST OF TABLES
Table 184.108.40.206: Guidelines of Drinking Water Quality (Source: FAR
(2062), WHO (1994), EPA (2006)) and Nepal Drinking
Water Quality Standards (2006)
Table 3.3.1: Methodology of Physio-chemical parameters and microbial
Results of the Presumptive Count during Jan/Feb (A)
Results of MPN test during Feb/Mar (B)
LIST OF FIGURES
Figure 4.1: Comparison between pH values
Figure 4.2: Graph showing Temperature values
Figure 4.3: Comparison of Conductance values in two tests
Figure 4.4: Comparison of Alkalinity values in two tests
Figure 4.5: Comparison between Hardness values
Figure 4.6: Graph showing the values of Free CO2 in two tests
Figure 4.7: Graph showing the values of Chloride in two tests
Figure 4.8: Comparison between DO values
Figure 4.9: Graph showing the values of Total Iron in two tests
Figure 4.10: Comparison between Nitrate-N values
Figure 4.11: Graph showing the values of Phosphate-P
Figure 4.12: Comparison between Ammonia-N values
Water is inevitably essential to sustain life. Out of total 3% of fresh water in the earth, 77%
are captured in the glaciers, 22% underground, 0.33% lakes, 0.18% soil moisture, 0.03%
rivers and 0.03% in the atmosphere. Majority of freshwater are locked as glacier and polar
ice which is difficult to utilize and importing them is costly. As fresh water resources are
further stretched to meet the demands of industry, agriculture and an ever expanding
population, the shortage of safe and accessible drinking water is estimated to become the
major challenge in many parts of the world. There are two major problems with the fresh
water of the earth:
1.1.1.. Fresh water shortage:
Large volume of water is captured in the ocean as salt water. Since majority of the fresh
water is stored in the glaciers and polar ice caps, there is a relative shortage of fresh water.
Lakes and rivers are the primary sources of fresh water for human consumption but they
only contain 0.26% of fresh water reserves and most of that is used for agriculture and
industry (Shiklomanov, 1993; Gleick, 1993; Chapagain and Hoekstra, 2004). The
remaining 30% stored as ground water, provides approximately 23% of the water used for
the human consumption (Pimentel et al., 2004). In addition, the available fresh water is not
uniformly distributed. 41% of the world’s population lives in areas characterized by either
water stress or water scarcity (Global Environment Facility, 2002). Approximately, 1.1
billion people face chronic shortages of safe water for drinking and sanitation (United
Nations, 2003; WHO/UNICEF, 2000).The condition is even worse in developing
countries. In fact, 30% of the rural populations in many developing countries still obtain
water from rivers dug pits, and other unsanitary sources (Olmstead, 2003).
1.1.2. Water Quality:
Although water is vital for life, it also serves as the commonest route of transmission of a
number of infectious diseases. Thus, water quality must be ensured before drinking and the
water we drink must be safe. Safe drinking water is defined as water with microbial,
chemical and physical characteristics that meet WHO guidelines of national standards on
drinking water quality (WHO, 2007).
The quality of water is reflected by various physical, chemical and biological conditions
which in turn are influenced by natural and anthropogenic sources. (ADB/ICIMOD).Water
quality parameters like alkalinity, hardness, Dissolved Oxygen (DO), chloride, Total
Dissolved Solid (TDS) etc add to the aesthetic value of water, while parameters like
ammonia, lead, arsenic, nitrate etc may cause adverse health effects. Water having high or
low pH, greater extent of turbidity etc. is objectionable to use. Appropriate amount of
chloride content and hardness are desirable but higher content of the same makes the water
unaesthetic. Similarly higher content of phosphate, nitrate, ammonia, iron, are undesirable.
Some other chemical constituents like arsenic, lead etc. may be toxic.
From microbiological point of view, drinking water should be free from any kinds of
pathogens as well as opportunistic microflora. Although there are a number of microorganisms present in water that may pose health threat like Salmonella spp, Shigella spp,
Coliforms, Mycobacterium spp etc., coliforms are used to assess water quality. Coliforms
are gram negative rod shaped bacteria capable of growth in presence of bile salts and able
to ferment lactose at 35-370 C with the production of acid, gas and aldehyde within 24-48
hours. They are oxidase negative and non-spore forming. Coliform organisms (E. coli)
have long been recognized as a suitable microbial indicator of drinking water quality
largely because it is easy to isolate and enumerate them. They are present in the intestine of
warm blooded animals including humans. Thus, their presence in water samples indicates
the presence of fecal matter and the possible presence of pathogenic organisms of human
origin. If other pathogenic microbes are used as an indicator, then there is high chance of
getting contaminated oneself and the sample taken should be large to trap pathogens, since
their numbers decrease as they mix with water.
The micro-organisms in water are capable of causing various diseases like typhoid,
cholera, diarrhea, dysentery, hepatitis etc. According to WHO (2002), unsafe water supply
is a major problem and fecal contamination of water sources and treated water is a
persistent problem worldwide. Globally, 1.1 billion people rely on unsafe drinking water
sources from lakes, rivers and open wells. The majority of these are in Asia (20%) and
Sub-Saharan Africa (42%) (WHO/ UNICEF, 2000; WHO/ UNICEF-JMP, 2004). The use
of these unsanitary sources helps to explain why 90% of human infections in less
developed countries are caused by water borne diseases (Pimentel et al., 2004). The WHO
has estimated that up to 80% of all sickness and disease in the world is caused by
inadequate sanitation, pollution or unavailability of water. Hence it is necessary to purify
and disinfect water before it is available for drinking.
Many researches and studies have revealed that tap water do not ensure the quality of
water. According to the National Water Quality Association, 56% of all people are worried
about the quality of municipally treated tap water. With the rising concern on public
health, people choose bottled water over tap water.
1.1.3. Bottled Water:
Bottled water is a term referring water that is presumed to be processed, packaged and
sold in containers or simply bottles. According to the International Bottled Water
Association, “Bottled water is a great beverage choice for hydration and refreshment
because of its consistent safety, quality, good taste and convenience”. Bottled water can be
categorized into Artesian well water, distilled water, mineral water, purified water,
sparkling water, well water etc according to their source and state of purification.
The mass production and marketing of bottled water exploded in the late 20th century. In
the global scenario, sales and consumption of bottled water have skyrocketed in recent
years. From 1988 to 2002, the sales of bottled water globally have more than quadrupled to
over 131 million cubic meters annually (BMC, 2003). Bottled water sales worldwide are
increasing at a rate of 10% annually (Bottled Water Web, 2003). One of the main reasons
of this is the compromised water quality provided by municipality. Another reason may be
the public perception that the bottled water is essentially of high quality.
The public perception and probably the reality is that bottled water is regularly of high
quality. This belief is encouraged by publicly reported problem of municipal tap water as
well as the public perception of purity driven by advertisements and packaging labels
featuring pristine glaciers and crystal clear mountain springs. However, many studies have
shown that these beliefs need not always be true. A four-year study conducted by the
National Resources Defense Council (NRDC, 1999) revealed that about one-third of the
samples contained significant contamination, including synthetic chemicals, bacteria and
arsenic, in at least one sample, out of more than 1000 samples of 103 bottled water brands
tested. It also concluded that “an estimated 25% or more of the bottled water is really just
tap water in bottle- sometimes further treated, sometimes not”. Even with limited
independent testing done for bottled water, problems are periodically discovered. Many
individual researches and studies in developed countries have shown that only because
water comes out of a bottle doesn’t mean that it is definitely purer and safer than the tap
water. Similarly, in the words of NRDC, “While much tap water is indeed risky, having
compared the available data, we conclude that there is no assurance that bottled water is
Environmental Effects of Bottled Water:
1. According to World Wide Fund for Nature (WWF), 2001 report, roughly 1.5 million
tons of plastics are expended in the bottling of 89 billion liters of water each year.
2. The recycling rate of these bottles is minimum which produces a serious problem of
waste management. 60 millions plastic bottles a day are disposed off in USA alone.
3. Energy required to manufacture and to transport these bottles to market severely drains
limited fossil fuels.
4. Reusing plastic PET bottles compromises the water quality. Moreover there are ongoing
arguments on the leaching of harmful chemicals from Poly-Ethylene Terephthalate (PET)
5. Bottled water industry is an exceptionally wasteful industry. More than three times
water is needed to fill 1 bottle of water.
6. There may be local effects due to bottling plants. Also, the question for the sustainability
of the bottled water sources may arise. In places where bottled water are filled from
underground aquifers, they may get depleted over time.
1.1.4. Water Related Problems in Nepal:
Nepal is a country with rich water resources. There are more than 6000 river and rivulets.
The average annual runoff within the Nepalese territory is estimated at about 174 billion
cubic meters. However, the management of this resource is very poor due to which many
cities and towns of this country are facing severe shortages. Nepal faces a number of
problems regarding both its drinking water quality and availability. Kathmandu, the capital
of Nepal, suffers a severe drinking water supply crisis, which becomes more pronounced
in the dry seasons. The existing water supply system of Kathmandu Upatyaka Khanepani
Limited (KUKL) produces about 120 million liters per day (MLD) in wet season and 80
MLD in dry season whereas the demand is around 320MLD. The KUKL supplies 40% of
its water from surface water sources while the rest 60% comes from the underground
sources. The municipal water supplies are inconsistent and unreliable. Not only the
shortages in quantity, but also the compromised quality of municipal tap water has become
a major public health issue. Throughout Nepal, people are exposed to severe health threats
resulting from water contamination by sewage, agriculture and industry. Owing to the
impact of sewage, typhoid, dysentery, and cholera are endemic every summer (Khadka,
1993). These diseases account for 15% of all illness and 80% of total deaths, but those
number increases to 41% of all illness and 32% of all deaths in children up to 4 years
(Sharma, 1990). Diarrhoeal diseases are recorded as the second most prevalent disease in
Nepal. According to Sharma, 2003, around 75 children die each day from diarrhea alone.
Recently, the diarrhoeal epidemic that affected the hills of mid and far-western districts
like Jajarkot, Rukum, Dang, Humla, etc in Bhadra, 2066 taking the lives of more than 200
people also makes us more concerned about the drinking water quality. Although being the
dwellers of the capital city, we are neither in the state to proclaim proudly that the water
we use is any purer nor can it be guaranteed that these kinds of epidemics can’t occur in
the valley. Thus, conveying message to the public about water quality and sanitation and at
the same time, using disinfectants to purify water is a must in the present scenario. In the
context of growing health consciousness and chronic water shortages, most of the urban
residents have switched to bottled water as a safe alternative.
1.1.5. Bottled Water In Nepal:
The history of bottled water in Nepal can be dated before 1992 when Star Water was the
only brand available. Subsequently, Aqua Minerals Nepal Private Limited was established.
Since then, the numbers of bottled water companies have been increasing. According to
the recent data provided by Company Registrar’s Office, there are 55 companies of bottled
water registered in the country out of which only few have received NS Standards.
PET bottles of 1 liter and jars of 20 liters are available in the market. The price of PET
bottles of 1 liter ranges from Rs.15-30 whereas for jar water ranges from Rs.100-750 with
refilling price ranging from Rs.45-150. PET bottles are discarded after use while jars are
taken back to the related companies and refilled. Jar water are commonly used for
household purposes as well as in offices, educational institutions and restaurants. Varieties
of brands of bottled water including jar water are available in the market at different price
rates and therefore, doubt about the quality can arise. The regulation and monitoring of the
quality of bottled water is not proper. In Nepal, the drinking water quality is assessed with
reference to the National Drinking Water Quality Standards (NDWQS). In addition to this,
WHO and EPA guidelines are also followed. The respective guideline values are tabulated
Table 220.127.116.11.: Guidelines of Drinking Water Quality (Source: FAR (2062), WHO (1994)
EPA (2006)) and Nepal Drinking Water Quality Standards (2006):
TDS ( mg/L)
mg/L(as CaCO3 )
1.2. STATEMENT OF THE PROBLEM:
Water quality has a direct impact on public health. More than 80% of deaths is caused due
to water borne diseases. The water supply system in Kathmandu valley is insufficient as
per demand of consumers due to centralization of Nepalese population day by day. The
people of Kathmandu valley show an increasing trend of using jar water, mostly driven by
the unreliable and quality compromised tap water supply and in part due to the perception
and expectation of pure and safe drinking water. With the increasing demand and
insufficient supply, it seems that in the near future, the urban dwellers would not have an
option other than using bottled/jar water. Thus it’s high time to check the quality and
monitor the bottled water industry. However, very few studies have been carried out to
assess their quality and there are no agencies that regularly monitor their quality.
Safe drinking water is a fundamental right of human being. However, is the water that we
drink safe? The answer is obviously “NO” as shown by the death statistics from water
borne diseases which accounts to 80%. Driven by the perception of purity, people switch
to buy bottled water. The question is not: why to check the quality of bottled water, it is:
why not? People have the right to know the quality of water that they perceive to be pure.
Hence, this case study is justifiable.
1.4. OBJECTIVES OF THE STUDY:
1.4.1. Broad Objective:
To analyze the water quality of various brands of jar water marketed in the
1.4.2. Specific Objectives:
To analyze the Physio-chemical parameters of jar water sold in Kathmandu valley.
To determine the bacteriological quality of jar water.
Sharma S., (1978) analyzed the household drinking water in 39 localities of Kathmandu
valley and found coliforms ranging from 4 to 460 cfu per 100 mL.
DISVI (1989) conducted a study on the quality of drinking water of Kathmandu valley by
taking 472 samples at 58 sampling points, 44 water taps, 7 storage, and 7 water treatment
plants which showed existence of bacterial contamination in most of the sampling points.
Ground water, a major source of drinking water in Kathmandu valley indicates high level
of iron, magnesium and ammonia (JICA, 1990)
ENPHO/DIVSI (1990) conducted a study on water quality of 21 stone spouts of
Kathmandu city .The results showed heavy bacterial contamination in 81% of the total
samples along with the presence of fecal contamination.
ENPHO/DIVSI (1992) conducted a one year monitoring on microbiological quality of
water supply in Kathmandu. Water samples were collected from 39 taps and 6 treatment
plants.18% of the treatment plants and 50% of public taps showed significant
Sharma S., (1993) studied the drinking water quality of Kathmandu and Pokhara.
Significant contamination was observed. Coliform counts of 2400/100 mL and 4800/100
mL respectively in the sampled areas.
The water supply system of Kathmandu is old and lack of maintenance has led to frequent
malfunction (ADB, 1995).
Masaaki N., and Hiroaki N., (1998) analyzed the bottled water in Kathmandu valley in
July 1997. Bacterial contamination of the bottles purchased in Kathmandu (n=23) were
checked using bacterial culture kit, "Test Paper for General Bacteria" and "Test Paper for
Coliform" (SAN Chemical Co. Ltd.), following the direction of the manufacturer, and
found that 7 bottles (30.4%) contained general bacteria, coliforms were detected in 4
bottles (17.4%) and 5 out of 23 bottles were found to have less content, i.e., water had
leaked while transportation. The conclusion drawn from this study was that water bottles
sold in the developing countries were contaminated with bacteria quite frequently.
Joshi, et al (1999) conducted a study of bottled water in Kathmandu valley. Twenty
different brands of mineral water were analyzed for hygienic quality and chemical
constituents. In the microbiological analysis, coliforms were detected in 3 samples with
fecal coliforms detected in 1 sample and Salmonella spp in 2 samples. The conclusion
drawn was that the bottled water is contaminated frequently.
Pokhrel S.R., (2000) analyzed 42 samples of bottled water from 7 companies for Physiochemical as well as microbiological parameters. He found that the physio-chemical
parameters were under the acceptable limit whereas, bacterial count up to 162 was found in
Total Plate Count. In addition to this, yeast as well as coliform was also detected.
Bittner A., et al (2000) carried out a study on the quality of drinking water of Kathmandu.
Samples were taken from various sources like well, stream and treatment plants, all of
which showed contamination. Hence it was concluded that most drinking water supplies in
Kathmandu are microbiologically contaminated.
Prasai T., et al, 2002, analyzed a total of 132 water samples collected from various sources.
Among the total samples, 49 were from tube wells, 57 from wells, 17 from taps and 9 from
stone spouts. The analysis was carried out for various water quality parameters. The results
showed that 82.6% of drinking water samples crossed WHO standards. During the study,
238 isolates of enteric bacteria were identified, of which 26.4% were Escherichia coli.
Centre for Science and Environment, India(2003) analyzed 26 samples of 13 bottled water
brands and raw water samples in Mumbai and found that every samples showed pesticides
concentration between 0.0007 to 0.0042 mg/L. The maximum concentration was 40 times
higher than European Economic Community (EEC) standards.
Ribeiro A., et al (2006), analyzed water quality from various sources in Portugal. The
objectives of this study were to analyze the seasonal fluctuations of fungal contamination,
and to trace the origin of the contaminating fungal populations with molecular biology
techniques in a bottled water company. He analyzed water from water tank, water filter
and bottled water twice monthly for fungal growth and found significant fungal
contamination. The dominant fungal genera in order of highest numbers isolated were:
Penicillium, Cladosporium and Trichoderma followed by Aspergillus, Paecilomyces and
others. He also observed that fungal contamination increased during the warmer seasons,
especially May and June.
Warner N.R. et al., (2007) studied drinking water quality in Kathmandu valley. Water was
sampled from over 100 sources including municipal taps, dug wells, shallow and deep
aquifer tube wells and stone spouts. They found that the most problematic were total
coliform and E. coli which was present in94% and 72% of all water samples respectively.
Contamination by nitrate, ammonia and heavy metals was more limited.
Gyawali R.,(2007) conducted a study on Microbial and chemical quality of water available
in Kathmandu with 6 samples of tap and river from Sundarighat upstream and found that
the physiochemical parameters were below WHO standards except chloride. Also,
bacteriological contamination was 900 cfu/100 mL in average.
Thakuri B.M., (2008) Conducted a study on the quality of bottled water in Kathmandu,
taking 10 different brands of bottled water available in the valley and found that most of
the Physio-chemical parameters were under the limit of WHO (1994). Microbial analysis
showed that most brands had satisfactory quality though few numbers of coliforms were
Pandey B., (2009) analyzed the drinking water quality of Central Development Region,
Nepal. He analyzed a total of 243 samples: 130 from ground water source and 113 from
springs. 20 of the ground water sample exceeded WHO standards. In addition to this, he
concluded that most of the springs and ground water sources were heavily contaminated
with fecal coliform bacteria.
3.1. SAMPLE COLLECTION, TRANSPORTATION AND PROCESSING
Samples of nine brands of jar water of 20 litres capacity were collected randomly from
various restaurants as well as from jar water selling shops. For analysis of physicochemical
parameters, water sample was collected in PVC sampling bottle. Some parameters such as
temperature, pH, chloride, dissolved oxygen (DO), hardness, alkalinity and free carbon
dioxide were determined in site while other parameters were determined in the laboratory of
Central Department of Environment Science T.U. For determination of iron contents, about
1ml conc. HCl was kept in the samples bottles before the collection of water sample, in order
to preserve the samples in reduced state. Samples for bacteriological analyses were collected
in sterilized bottle, stored in ice cold box and transported to laboratory and were processed
within 6 hours of collection.
3.2. SAMPLING FREQUENCY:
Water quality was analyzed twice for each brand of bottle water during months of January,
February and March when the difference in daily temperatures and change in season
proceeds. The methodologies used to analyze various parameters are described below.
3.3. ANALYSIS OF WATER SAMPLES
3.3.1. Analysis of physicochemical parameters of water samples:
"Standard Methods for the examination of water and wastewater", (APHA, 1998) was
followed to analyze most of the physicochemical parameters of water.
3.3.2. Analysis of microbial variables of water sample:
Microbial analysis was carried out following the "Standard Methods for the examination of
water and wastewater", (APHA, 1998) and "Chemical and Biological methods for water
pollution studies", 18th edition, R.K. Trivedi and PK. Goel 1984".
Table 3.3.1.: Methodology of Physico-chemical parameters and microbial analysis
Total Coli form &
Winkler’s iodimetric titration
For the determination of the temperature, water was collected in a beaker. Mercury filled
Celsius thermometer was inserted into the beaker and reading was noted.
pH was measured by automatic digital pH meter. The pH meter was first calibrated with a
standard buffer solution. The glass electrode was washed with distilled water. Then glass
electrode was dipped in the beaker containing water sample until the reading stabilized at a
certain point. Then pH reading was noted down.
The instrument used was digital conductivity meter. The conductivity meter was first
calibrated with standard Potassium chloride solution of 0.01N. Then reading was noted.
Chloride was measured by titration method. 50 mL of sample in a conical flask was taken.
2 mL of Potassium chromate was added to the sample solution. It was titrated against
0.02N silver nitrate until a persistent brick red color was appeared which was the end point
of the titration. A blank by placing 50 mL of chloride free distilled sample water was also
Chloride (mg/L) = (a-b) × N ×35.5 × 1000
Where, a = Volume of titrant (silver nitrate) for sample
b= Volume of titrant (silver nitrate) for blank
V = Volume of the sample in mL
N = normality of silver nitrate
Hardness is caused by the calcium and magnesium ions present in water. Total hardness
was determined by EDTA method. This was done by titrating 100mL of sample in a
conical flask and adding 1mL of buffer solution with Erichrome Black-T indicator against
standard EDTA (Ethylene diamine tetra acetic acid). The solution was changed from wine
blue at the end point. Total hardness might be caused by the sum of all metallic cations
other than alkali metals and expressed as equivalent calcium carbonate concentration.
Total hardness (as CaCO3), (mg/L) = mL of EDTA used×100
mL of sample
6. Calcium hardness
Calcium hardness was determined by the same procedure as total hardness. Taking 50mL
sample in a conical flask with 2mL of NaOH solution of 1N was titrated against EDTA
solution using murexide indicator. At the end point, pink color changed to purple.
Calcium, mg/L (as CaCO3) = Vol. of EDTA×N × 40.08 × 1000
Vol. of sample
7. Magnesium hardness
Magnesium salts occur in significant concentration in natural waters which may be
calculated as the difference between total hardness and calcium hardness.
Magnesium hardness, mg/L (as CaCO3) = Total hardness – Calcium hardness
8. Free CO2
Free CO2 in water can be determined by using titration method. For this 100 mL of sample
was taken in a conical flask and 2 drops of phenolphthalein indicator was added. Then it
was titrated against 0.05N of NaOH from the burette until pink color was just appeared.
Free CO2 (mg/L) = A × Normality of NaOH × 44 ×1000
Volume of sample in mL
Where, A = Volume of NaOH used in mL
9. Dissolved Oxygen ( Winkler’s Method )
DO was measured by using APHA, (1998) method. The sample was collected in a 300 mL
BOD bottle carefully, avoiding any kinds of bubbling and trapping of air bubbles in the
bottle after placing the stopper. To the 50 mL sample taken in the conical flask 2 mL of
manganese sulphate (MnSO4) and 2 mL of Sodium azide solution was added well below
the surface from the wall of the bottle. A precipitate was appeared. Then the stopper was
placed tightly and the bottle was shaken by inverting the bottle repeatedly to insure proper
mixing of the contents. The bottle was kept for some time to settle down the precipitate, 2
mL of conc.H2SO4 was added to it and shaken well to dissolve all the precipitate. Then 50
mL of sample were taken in a conical flask and titrate against sodium thiosulphate
(Na2S2O3) of 0.025N using starch as an indicator. At the end point the initial blue color
changed to colorless.
DO (mg/L) = (mL× N) of titrant ×8 ×1000
Where, V1= volume of sample bottle after placing the stopper
V2= volume of part of content titrated
V= volume of MnSO4 and KI added
10. Total Alkalinity
Total Alkalinity is the measure of the capacity of the water to neutralize a strong acid. The
alkalinity in water is generally imparted by the salts of carbonates, bicarbonates,
phosphates, nitrates, borates, silicates etc. together with hydroxyl ions in free state.
Total alkalinity of water was determined by titrimetric method. 100mL sample in a conical
flask with 2-3 drops of methyl orange was titrated against standard, 0.02N H2SO4. At the
end point, yellow color was changed to pink color.
Total Alkalinity (mg/L) = a ×N×1000×50
mL of sample
where, a= Volume of standard H2SO4 consumed in titration
N= Normality of H2SO4 used
11. Phosphate – P
Phosphate content in the given water sample was determined as inorganic phosphate by
calorimetric method. In this method, 50mL of the filtrate clear sample was taken in a
conical flask. 20 mL of ammonium molybdate was added to it. 5 drops of SnCl 2 solution
was added to it. The solution becomes blue and the reading was taken at 690 nm on the
spectrometer within 10-12 minutes. Same procedure was repeated for the standard solution
of different concentration for distilled water. The concentration was determined with the
help of standard curve obtained by plotting standard values against absorbance.
Nitrate content in the water sample was determined by Phenol disulphonic acid method. In
this method, 50 mL of filtrate sample was taken in a porcelain basin and was evaporated to
dryness. It was cooled and residue was dissolved in 2 mL of phenol disulphonic acid and
was diluted to 50 mL. 6 mL of liquor ammonia was added to develop yellow color. Then
the reading was taken at 410 nm on spectrophotometer. Same procedure was repeated for
the standard solution of different concentration and for distilled water. Then the
concentration of Nitrate-N was determined from the standard curve obtained by plotting
standard value against absorbance.
Ammonia content in a water sample was determined by colorimetric method. In this
method 100 mL of water sample was taken in a volumetric flask. 1 mL of ZnSO4.7H2O
was added, 1 mL of 10% NaOH was added into it. Then it was stirred and filtered. One
drop of 50% EDTA was added and well mixed. Then 2 mL of Nessler’s reagent (K2HgI4)
was added. Then the reading was taken at 420 nm on spectrophotometer. The same
procedure repeated for the standard solution of different concentration. Then the
concentration determined with the help of standard curve.
14. Total Iron
Iron content in the water sample was determined by colorimetric method. In this method
50 mL of the sample was taken in a conical flask. 2 mL of concentrated HCl and 1 mL of
hydroxylamine hydrochloride solution was added. Then some glass beads were put in the
flask and boil till the content is reduced about half. It was cooled and 10 mL of acetate
buffer solution and 2 mL of Phenothroline solution was added, then orange red color was
appeared. Distilled water was added to make the volume 100 mL in a volumetric flask. Let
it stand for 10 minutes, and the absorbance of the color was measured by using
spectrophotometer at 510 nm using distilled water blank with the same amount of
chemical. The same procedure was repeated for standard solution of different
concentrations. Then the concentration was determined with the help of standard curve.
15. MPN Test:
The purity of drinking water regarding bacterial contamination is evaluated by testing the
presence of coliforms as these are designated as indicator organism of faecal
contaminations. Coliform bacteria in the water sample were determined by Most Probable
Number (MPN) or Multiple - Tube fermentation test. This test is performed sequentially in
Presumptive coliform test:
This is used to detect coliforms in a water sample. In this test lactose fermentation
tubes (Mac-Conkey Broth) were inoculated with different water volumes and
production of acid and gas from the fermentation of lactose within 48 hrs in any of
the tubes was the presumptive evidence of coliforms in the water sample.
a) 10 mL of water sample was inoculated in each of 3 tubes containing 10 mL of the
double strength of Mac-Conkey broth.
b) 1 mL of water sample was inoculated in each of 3 tubes containing 9 mL of the
single strength of Mac-Conkey broth.
c) 0.1 mL of water sample was inoculated in each of 3 tubes containing 9.9 mL of the
single strength of Mac-Conkey broth.
All the inoculated tubes were incubated at 37° C for 24 hours. After incubation, the
tubes were counted which had produced both acid and gas. The tubes showing
negative result were further incubated at 37° C for 24 hours. The tubes showing gas
formation and acid formation were further inoculated for confirmatory test.
2) Confirmed coliforms test:
This test is used to confirm the presence of coliforms and to determine the MPN
value in water sample. In this test water samples from all the positive presumptive
Mac Conkey broth tubes were inoculated into two sets of tubes of BGLB (Brilliant
Green Lactose Bile salt) broth and one set incubated at 37oC for 24-48 hours- for total
coliform and another incubated at 440 C in water bath for 24 hours for fecal coliform.
Positive confirmed tubes were used to determine MPN/100ml by following statistical
Method (MPN table).
3) Completed coliforms test:
This test is used to establish the presence of Total Coliform as MPN/100 ml in a
water sample. Positive tube from the confirmatory was streaked on the plate of EMB
Agar and incubated it at 37° C for 24 hours. After 24 hours, the colonies that had
typical growth (dark centre with greenish metallic sheen) and atypical growth were
transferred to nutrient agar slant and Mac Conkey Broth and incubated at 37° C for 24
hours. The presence of total coliform and faecal coliform bacteria was confirmed by
Gram Staining and Spore Staining Technique.
RESULTS AND DISCUSSION
The table with respective values of each of the parameters is shown in the annex.
Fig 4.1: Comparison between pH values
pH is the negative logarithm of hydrogen ion concentration. It is used to express the
intensity of acidic or alkaline condition of a solution. The pH values in all the samples
tested during Jan / Feb. and Feb. / March range from 6.5-7. pH of pure water is 7. pH
is an extremely important variable because it is the controlling factor determining the
solubility of most metals and also because most micro-organisms can survive within a
narrow range of pH. pH is also an important factor in water treatment. Proper
chemical treatment of water including disinfection requires pH control. The values of
pH obtained are within the WHO standards of 6.5-8.5.
Fig 4.2: Graph showing temperature values
Temperature of fresh water varies normally from 0 to 35ºC depending on the source, depth
and season. The temperature of water affects some important physical properties and
characteristics of water such as density, viscosity, conductance, salinity, solubility of
dissolved gases etc. Also, chemical and biological reaction rates increase with temperature.
In the above graph, the temperature in the first test during January/February shows range
between 15-18 ºC and in the second test conducted during February/March, the ranges are
between 19-23 ºC.
Fig 4.3: Comparison of conductance values in two tests
Electrical conductivity is the measure of the capacity of water to conduct electric current.
The values of conductance range from a minimum of 15µs/cm for brand 3 to a maximum
of 815µs/cm for brand 4 in first test. Similarly in the second test minimum value is 70
µs/cm for brand 3 and maximum value is 768 µs/cm for brand 4. In comparison of other
brands, brand 4 has high conductance. High values of conductance indicate high dissolved
gases and other chemicals in the water. There is no guideline value for conductivity;
however, values above 400us/cm may affect the chemical quality of drinking water.
Fig 4.4: Comparison of alkalinity values in two tests
Alkalinity is also a major parameter affecting water quality that mainly acts for pH
neutralization. Alkalinity measurements are used as the means for evaluating the buffering
capacity of water. The minimum values of alkalinity were 15mg/L for brand 2 and 25
mg/L for brand 3 in the 1st and 2nd tests respectively, while the maximum values were 90
mg/L for brand 7 and 142 mg/L for brand 5 in the 1st and 2nd tests respectively. These
values are well below the permissible limits. However, there is an increasing trend of
alkalinity values. In natural water, most of the alkalinity is caused by CO2. Since the
concentration of free CO2 also has increased in the second test, the rise in the values of
alkalinity in the 2nd test seems to be obvious.
Fig 4.5: Comparison between the hardness values
Hardness is imparted to the water mainly by calcium and magnesium ions. Calcium is
essential element for human beings (nearly 2 gm per day) and plant growth. However, hard
water is generally undesirable because it forms precipitate with soap, produces scales in
boilers on heating and has high boiling point due to which it is unsuitable for cooking. The
minimum values of total hardness were 10mg/L for brand 8 and 8 mg/L for brand 2 and 8
in the 1st and 2nd tests respectively, while the maximum values were 80 mg/L for brand 7
and 76 mg/L for brand 5 in the 1st and 2nd tests respectively. The WHO standard for
hardness is 200mg/L. Thus all the values are within acceptable limits.
The minimum values of Calcium hardness were 6mg/L for brand 8 and 4 mg/L for brand 2
in the 1st and 2nd tests respectively, while the maximum values were 46mg/L for brand 7
and 42 mg/L for brand 5 in the 1st and 2nd tests respectively. Similarly, for magnesium
hardness, the maximum values were 34 mg/L for brand 7 and 34 mg/L for brand 5 in the
1st and 2nd tests respectively and minimum values for 1st and 2nd test were 4 mg/L for brand
8 and 2 mg/L for brand 8 respectively.
6. Free CO2:
Fig 4.6: Graph showing values of Free CO2 in two tests
Surface water normally contains less than 10mg/L of free CO2 while some ground water
may contain 30-50mg/L of free CO2. High concentration of free CO2 indicates pollution
from domestic sewages and industries. However, there are no prescribed limits of free CO 2
for drinking water as free CO2 do not bring about physiological effects. The values for free
CO2 for most of the samples are zero in the 1st test except brands 6, 7, and 8 whereas in the
2nd test. All the sample show significant values with a maximum of 48.4 mg/L for brand 8
and a minimum of 6.6 mg/L for brand 5.
Fig 4.7: Graph showing chloride values in two tests
Chloride is present in appreciable amounts in all natural water. Concentration varies from
few milligrams to several thousand milligrams per liter. High concentration of Chloride
may indicate pollution of organic origin, as well as results in corrosivity and impaired
taste. The permissible limit of chloride according to WHO is 250 mg/L. Drinking water is
often chlorinated for disinfection. The concentration of chloride is high for brand 4 in both
the months. The values of chloride range from 1.42-86.62 mg/L in the 1st test and 8.5293.72 mg/L in the 2nd test. All the values are within WHO guidelines.
8. Dissolved Oxygen (DO):
Fig 4.8: Comparison between DO values
Oxygen is dissolved in water in varying concentrations. It is a very important water quality
parameter and is also an index of physical and biological processes going on in water.
Analysis of DO is very important in water pollution control. The guideline value for DO is
>5 mg/L according to WHO. Brand 9 shows higher DO values among all. The obtained
values are in the range 7.7-8.2 mg/L in the 1st test and 6.9-9.3 mg/L in the 2nd test which
satisfy WHO standards.
9. Total Iron:
Fig 4.9: Graph showing the values of Total Iron
Iron has got a little concern as health hazard, but it still is considered as a nuisance in
excessive quantities. High iron content produces bitter and astringent taste. The WHO has
set the permissible limit of iron to 0.3 mg/L. Among all brands, brand 9 has the highest
iron concentration in both the months. The values of iron range from 0.014-0.1 mg/L in the
first test to 0.015-0.12 mg/L in the 2nd test which all lies below the acceptable limits.
10. Nitrate- N:
Comparision between nitrate values
Fig 4.10: Comparison between Nitrate-N values
Nitrates are present in trace amounts in surface water but in some ground water, nitrates
may be high. High nitrite and nitrate concentration in water causes a disease called
methemoglobinaemia. In drinking water, nitrate concentration should be less than 10 mg/L
according to WHO. The values obtained are in the range of 0.01-0.02 mg/L in both tests,
all below the permissible limits.
Fig 4.11: Graph showing values of Phosphate-P
Though in low concentration, phosphate is an important nutrient present in water. The
values of phosphate range from 0.14-0.32 mg/L in the first test and 0.15-0.29mg/L in the
2nd test. The highest value of phosphate is seen for brand 9 in both the months.
Comparision between ammonia values
Fig 4.12: Comparison between ammonia-N values
Ammonia is generally an indication of pollution in drinking water. According to the
guideline value given by WHO, the concentration of ammonia should be 0 mg/L. The
maximum concentration of ammonia was found to be 0.01 mg/L and in most of the test
was undetectable, that means, less than 0 mg/L.
13. Bacteriological examination:
Table 4.13.1 Bacteriological examination water during January/February
Presumptive count/100 mL
In the presumptive count, out of nine brands, 6 brands were found to be contaminated with
coliform. Brands 4, 5, and 9 were found to have no contamination.
Table 4.13.2: Bacteriological examination water during February/March
In this test, only one brand was found to be devoid of both total and fecal coliform while
two other brands showed total coliform but no fecal coliforms and the rest brands showed
both total and fecal coliform. Among the samples, brands 1, 2, 7 and 8 were found to be
Analysis of physicochemical parameters during January/February showed that the pH of
the samples range from 6.55 to 7.63. Temperature of the samples range from 16-18°C.
Conductance was found to be as low as 15µs/cm for brand 3 and as high as 815 µs/cm for
brand 4. The value of alkalinity was also found to be variable. It ranged from a minimum
of 10 mg/L for brand 2 to 90 mg/L for brand 7. The values of hardness range from 10 to
68( as CaCO3 ).The values of Free CO2 was found to be 0 in most of the brands while
brand 7 showed a maximum value of 17.6 mg/L. The values of chloride were also highly
variable. The value was below 10 mg/L for 5 brands and a maximum of 86.62 mg/L was
obtained for brand 4. The values of DO were more or less similar and ranged from 7.7 8.2 mg/L. The value of iron was obtained in a range of0.04-0.05 mg/L except brand 9
which showed a value of 0.10 mg/L. The values of nitrate obtained were in the range of
0.01 - 0.02 mg/L. Similarly the values of phosphate were in the range of 0.14 - 0.32 mg/L.
Ammonia was not detected in any of the samples.
During Jan/Feb, only three samples of brands 4, 6, and 9 have no coliforms at all. That
means 66% of the sample is heavily contaminated. According to the WHO limit for the
Presumptive count, greater than 10 presumptive count/100mL are unsatisfactory. Due to
unforeseen circumstances as well as physical constraints, completion of MPN test was
Similarly, Analysis of physicochemical parameters during February/March showed that
the pH of the samples range from 6.81 to 7.89. Temperature of the samples range from 19
-23°C. Conductance was found to be as low as 70µs/cm for brand 3 and as high as 768
µs/cm for brand 4. The value of alkalinity was also found to be variable. It ranged from a
minimum of 25 mg/L for brand 3 to 142 mg/L for brand 5. The values of hardness range
from 8 to 76(as CaCO3).The values of Free CO2 was found in a range between 6.6 - 48.4
mg/L. The values of chloride were 8.52 mg/L for brand 1 and a maximum of 93.72 mg/L
was obtained for brand 4. The values of DO ranged from 6.9 – 9.3 mg/L. The value of
iron was obtained in a range of 0.05-0.07 mg/L except brand 9 which showed a value of
0.12 mg/L. The values of nitrate obtained were in the range of 0.01 - 0.02 mg/L. Similarly
the values of phosphate were in the range of 0.15 - 0.29 mg/L. Ammonia was not detected
in any of the samples.
During Feb/Mar, with the onset of summer, the MPN count/100 mL has also increased.
Total coliform was found to be Nil in only one sample (Brand 9) whereas fecal coliform
were found to be nil in 3 samples, Brand 4, 6 and 9. In the second test, total coliforms were
present in 89% of the total sample and fecal coliform was present in 66% of the total
Brand 4 and 5 showed no contamination in the first test but showed contamination in the
second test. This may be partly because of increased microbial activities with the onset of
summer or due to the contamination of jar. Even two jars of same brand may vary in
quality since during refilling and processing, contamination may occur. Similarly, there is
no assurance whether these jars are even processed.
The results show that the samples are heavily contaminated with coliforms. It may be due
to the improper water processing techniques as well as jars. Furthermore, the source of jar
water is not mentioned in any of the jars.
CONCLUSION AND RECOMMENDATION
Hence from the above results, it can be concluded that jar water, although thought
to be pure, cannot be relied upon for its safety. Various physio-chemical parameters like
DO, hardness, total iron, phosphate, nitrate, ammonia, alkalinity, pH, etc were analyzed
using standard methods of APHA (1998). All the Physio-chemical parameters like DO,
hardness, alkalinity, pH were within WHO acceptable limits. Ammonia was detected in
some samples but is within the limits set by WHO. Iron and Nitrates were found in small
quantities but within the limits set by WHO. With the onset of summer, the concentration
of some parameters rose like Free CO2, conductance, alkalinity etc, which are more or less
affected by temperature. Thus from the physio-chemical aspect, the quality of water is
From the microbiological point of view, 66% of the total samples were heavily
contaminated with total coliforms in the first test during January/February. Three brands of
jar water tested had no coliforms at all. During the second test in February/March, 89% of
the total sample was found to be contaminated with total coliforms whereas 66% were
contaminated with fecal coliforms. Total coliforms as many as 1100 MPN/100mL and a
maximum of 20 MPN/100 mL of fecal coliforms were enumerated. Hence, it can be
concluded that the water samples are heavily contaminated with coliform bacteria and
unsatisfactory for drinking purpose.
As per the NRDC (1999) result says, “While much tap water is indeed risky,
having compared the available data, we conclude that there is no assurance that bottled
water is any safer.” Similar is the conclusion of this study, that there is no assurance that
since water comes out of a bottle does not mean it is free from contamination.
1. There are varieties of jar water and their quality also varies. Thus it is necessary to pick
up the right brand.
2. Stricter rules should be made and implemented to regularly monitor the bottled water
3. The labels of bottled water must include not only the pristine glaciers and Himalayan
springs but also the relative concentrations of water quality parameters.
4. Since jar water are reused, sometimes they are used up to the extent that there is neither
company name nor any labels. In such condition, the jar may itself contaminate the water
although the water is safe.
5. All the bottled water companies should fulfill the basic water quality standards given by
the Government of Nepal and then registered to NS Standards since only three companies
have done it so far.
6. Awareness should be created to public for either using disinfectants or boiling water
before use rather than rely on the belief of purity.
ADB(2004) Water for all: The impact of water on the poor, Asian Development Bank,
APHA. ,1998: Standard methods for the examination of water and waste water. 20th
edition, American Public Health Association, Washington D.C. 1-47 pp.
Bittner A., Halsey T., Khayyat A., Luu K., Maag B., Sagara J., and Wolfe A., (2000),
“Drinking Water Quality and Point – of – use Treatment Studies in Nepal”
CBS. 2001. Statistical Year Book of Nepal HMG, Central Bureau of
Chapagain, A.K., and Hoekstra, A.Y. (2004) Water Footprints of Nation: Volume I: Main
Report, UNESCO- IHE, Institute for Water Education, Value of water: Research Report
Series no. 16, pp. 75.
Diwakar J. (2007), “Assessment of Drinking Water Quality of Bhaktapur Municipality,
M.Sc. Thesis, Central Department of Environment Science, TU.
ENPHO (2001), “Drinking Water Quality and Sanitation Situation in UNICEF’s project
area: Kavre, Parsa and Chitwan, September 2001.”
Government of Nepal, National Drinking Water Standards, 2062 and National Drinking
Water Quality standard Implementation Guideline, 2062 year: 2063 B.S. Government of
Nepal, Ministry of Physical Planning and Works, Singhadurbar, Kathmandu, Nepal.
Gyawali R.,(2007), “ A Study on Microbiological and Chemical Quality of Water of
Kathmandu” M.Sc. Thesis, Central Department of Microbiology, TU.
Masaaki N., and Hiroaki N., (1998), “Quality of the bottled water in Nepal”, Japanese
Journal of Mountain Medicine, Vol.18, pp 107-110.
Pandey B., (2009), “A Case Study of Drinking Water Quality Status in Central
Development Region, Nepal”
Pimentel D., Berger B., Filiberto D., Newton M., Wolfe B., Karabinakis E., Clark S., Poon
E., Abbett E., and Nandagopal S.,(2004) Water Resources, Agriculture and the
Environment, Report 04-1, Cornell University, College of Agriculture and Life Sciences
Prasai T., Lekhak B., Joshi D.R.,and Baral M.P., “Microbiological Analysis of Drinking
Water of Kathmandu Valley”, Nepal Academy of Science and Technology, Kathmandu,
Ribeiro, A., Machado, A.P., Kozakiewicz, Z., Ryan M.,Luke B., Buddie A.G., Venancio
A., Lima N.and Kelley J. (2006), “Fungi in Bottled Water, ACase Study of a Production
Shrestha RR, Sharma S., Bacteriological Quality of Drinking Water in Kathmandu City:
A Review of ENPHO/DISVI Reports, 1988-1992, (Katmandu: Environment and Public
Health Organization, 1995)
Thakuri B.M., (2008), “Analysis of Bottled Water Available in Kathmandu Valley”,M.Sc.
Thesis, Central Department of Environment Science, TU.
The World’s Water, “The Biennial Report on Fresh Water Resources: 2004-2005”, Island
United Nations (2003), “Water for People, Water for Life: A Joint Report by the 23 UN
Agencies concerned with Fresh Water, The UN World Water Development Report.
WHO. 1993. Guidelines for Drinking Water Quality, Volume I, II and
III, World Health Organizations, Geneva.
WHO. 1996. Guidelines for Drinking Water Quality 2nd edition. Volume
II, Health criteria and other supporting information. World Health
MPN DETERMINATION FROM MULTIPLE TUBE TEST
NUMBER OF TUBES GIVING
POSITIVE REACTION OUT OF
3 of 10
3 of 1
3 of 0.1
From: Standard Methods for the Examination of Water and Wastewater, Twelfth
edition. (New York: The American Public Health Association, Inc., p. 608.)
WHO Standards For Presumptive Coliform Count:
0, 1, or more
Composition of Eosin Methylene Blue (EMB)
Peptic digest of animal tissue
10.00 gm / Ll
2.00 gm / L
5.00 gm / L
5.00 gm / L
Eosin – Y
0.40 gm /Ls
0.65 gm / L
13.50 gm / L
Final pH at 25ºC → 7.2 ± 0.2
Composition of Nutrient Agar
Peptic digest of animal tissue
Final pH at 25ºC → 7.2 ± 0.2
5 gm / L
1.5 gm / L
1.5 gm / L
5.0 gm / L
15.0 gm / L
Composition of Mac Conkey Broth
Peptic digest of animal tissue
20 gm / L
10 gm / L
5 gm / L
5 gm / L
0.075 gm / L
Final pH at 25ºC → 7.2 ± 0.2
Composition of Brilliantly Green Lactose Bile Growth (BGLB)
Peptic digest of animal tissue
10 gm / L
10 gm / L
20 gm / L
0.0133 gm / L
Final pH at 25ºC → 7.2 ± 0.2