Transcript Andrew Paek and

Water
By:
Andrew Paek
Nirav Parekh
Background
 Water is an essential part of our well being
 We use it for nourishment, cooking,
cleansing, and many other things.
 Because of water’s importance, there are
methods used to purity water to make safe
for human consumption.
 Federal regulations are put in place to
ensure this safety.
Purification
 To purify water…
 1) Raw water (untreated water) is pumped into a
sediment basin where large particles such as sand
settle to the bottom.
 2) The sediment free water is then pumped into the
coagulation basin where the anionic polymers and
chlorine added to the sediment basin, which helps
form larger insoluble particles out of the suspended
tiny particles in the water.
 3) The water is filtered to remove remaining solutes,
suspended particles and microorganisms
Disinfection
 Filtered water must be disinfected before it
is released as drinking water
 Chlorine is the most common disinfectant
 Kills microorganisms within 30 minutes
 Neutralizes organic compounds
 Improves water taste and smell
Regulations
 There are certain bacteria known as coliforms
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which are used to indicate if water is
contaminated.
Based on the Safe Drinking Water Act, water is
only considered safe if the average number of
coliform bacteria does not exceed 1 CFU/100
mL
Water utilities report results to the EPA if they
don’t meet standards
The public is also informed
Outbreaks are reported to the CDC
Hypothesis
 We predict that water from various drinking sites
on campus will meet federal regulations. As of
now, there isn’t any kind of public announcement
that the water on campus isn’t safe to drink, so it
can be assumed that the water on campus
meets federal drinking regulations.
 We predict that we will not find any coliforms in
the water samples intended for drinking.
Methods
 Obtained three 100 mL samples of water
at five sites on this campus:
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Dorm water fountain
Dorm shower
Dorm sink
Outdoor fountain
Diner drinking water
 These samples were filtered, incubated,
and the number of colonies were counted
Membrane Filtration Method
 1) Shake each 100ml sample in their
containers at least 25 times.
 2) Pour 100ml of each sample into the
filter apparatus.
 3) Allow the water to filter for at least an
hour.
 4) Pour each of the 2ml ampules of the mcoliblue24 broth into each sample.
Rational for MF method
 The m-coliblue24 broth is a type of media
that selects for coliforms. It’s also a
differentiatial media which detects
between E.Coli and other coliforms.
 The membrane filtration method allows us
to count the number of colony forming
units which allows us to determine if the
water samples meet federal regulations.
Plating and Enterotubes
 We inoculated the Eosin-methylene blue
plates with unique colonies found from the
filters.
 From the pure colonies we inocoluated
enterotubes which tests for various
characteristics of the colonies found in the
water samples.
 These methods are used to identify the
coliforms found in the water samples.
Expected Results
 For the MF technique:
 Total coliforms would appear as red colonies.
 E.coli would appear as blue colonies.
 For the eosin-methylene blue media:
 Only coliforms should be able to grow.
 Lactose fermenters such as E.coli would
appear with a green sheen.
Results
 No coliforms were detected in these water
samples:
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Dorm water fountain
Dorm shower
Dorm sink
Diner drinking water
 Colonies were found from the outdoor
fountain.
Filters from the Outdoor fountain
Filter 1
5 brown and 3
pink/purple
colonies
Filter 2
1 brown and 5
pink/purple
colonies
About 80 tiny
purple colonies.
Filter 3
No colonies
observed.
Filter 2
EMB Plates
Outdoor Filter 1
Control E.Coli
Enterotube Results
Glucose
Lysine
Ornithine
H2S
Indole
Donitol
Lactose
Arabinose
Sorbitol
Voges Proskauer
Dulcitol
PA
Urea
Citrate
Control: e.coli
+gas
+
+
+
+
+
-
Outdoor Filter 1 colony
+
Analysis
 Since no coliforms were present in the sites
where people drink water, we can conclude that
the drinking water here on campus is safe
according to federal regulations.
 DON’T DRINK WATER FROM THE OUTDOOR
FOUNTAINS.
 The isolated colonies found on the filter could
possibly be from the genus Pseudomonas,
which doesn’t produce acids or gas from
glucose. These are normally found in soil and
water.
Implications of coliforms
 We’re interested in finding bacteria called
coliforms, which are facultatively aerobic, gramnegative, nonspore-forming, rod-shaped
bacteria which are able to ferment lactose and
produce gas.
 Their presence could indicate that the water
contains fecal matter.
 Coliforms are not necessarily responsible for
serious illnesses .
 If the water is dirty enough to have fecal matter,
chances are that there are pathogens in the
water as well.
Implications (cont.)
 Some of the main microorganisms which
cause serious waterborne illnesses:
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Typhoid fever – Salmonella typhi
Cholera – Vibrio cholerae
Legionellosis – Legionella pneumophila
Giardiasis – Giardia Intestinalis
Amebiasis – Entamoeba histolytica
Frequency of disease in the US
 In the year 2001-2002 there were 6 outbreaks
caused by the bacteria Legionella which resulted
in:
 Illnesses in 80 people
 41 hospitalizations
 Four deaths
 This was the most prevalent cause of
waterborne illness out of the other causes
including chemicals, parasites, viruses, and
other bacteria.
Legionellosis
 An intracellular parasite that grows in alveolar
macrophages and monocytes.
 Leads to pneumonia or a mild infection known as
Pontiac fever
 Symptoms:
 High fever
 Cough
 Muscle aches and headaches
 Treatment
 Antibiotics – rifampin and erythromycin
 Prevention
 The bacteria can be killed in the water supply through
hyperchlorination or heating the water to temperatures greater
than 65 degrees Celsius.
Protocol Evaluation
 Water samples were
not dechlorinated
which could have
inhibited growth.
 As seen on the
control, some bacteria
may not have grown
on raised parts of the
filter.
Comments on the results
 In the enterotube that tested the sample from the
outdoor fountain, only the last test was positive. This is
very unusual since coliforms should be able to ferment
some kind of sugar being facultative anerobes. This
colony should be tested again for identification.
 Only two out of six colonies (including the control) from
the filter membranes were able to grow on the EMB
agar. The process which the m-coliblue24 broth and the
EMB agar select for coliforms may be different between
each other. This would cause one media to select
against some colonies which may have grown in the
other media.
Overall significance of the Project
 Based on our tests on the water samples
across campus, we can conclude that the
water is safe to drink.
 We can also conclude that water in
outdoor fountains contain fecal matter. So
it’s advised that nobody drinks or touches
it.
THE END
 Bibliography
 Madigan, Michael and Martinko, John. Brock
Biology of Microorganisms. Upper Saddle River,
NJ: Pearson Prentice Hall. 2006
 Centers for Disease Control and Prevention.
Surveillance for waterborne-disease outbreaks
associated with recreational water — United
States, 001–2002 and Surveillance for
waterbornedisease outbreaks associated with
drinking water — United States, 2001–2002. In:
Surveillance Summaries, October 22, 2004.
MMWR 2004:53(No. SS-8).