Coliform Bacteria (needs 48 hour incubation)
Coliforms are a group of bacteria that are readily found in soil, decaying vegetation, animal feces, and raw
surface water. They are not normally present in deep groundwater and treated surface water.
Coliform bacteria originate as organisms in soil or vegetation and in the intestinal tract of warm-blooded
animals (fecal coli). This group of bacteria has long been an indicator of the contamination of water and possible
presence of intestinal parasites and pathogens.
The many sources of bacterial pollution include runoff from woodlands, pastures and feedlots; septic
tanks and sewage plants; and animals and wild fowl. Domestic animals contribute heavily to the bacterial
population. Many coliform bacteria enter natural streams by direct deposition of waste in the water and the runoff
from areas with high concentrations of animals or humans.
Q: Where else could coliform bacteria come from?
A: Don't always blame the water first. Who sampled the water and how? How sanitary are your practices
in food handling, personal hygiene, etc.? Do children wash regularly? While uncomfortable and personal subjects
to some, these are more likely routes for contamination than the water itself.
Did you know?
- Up to half of all men and a quarter of women fail to wash their hands after they've been to
- Right handed people tend to wash their left hand more thoroughly than their right hand, and
- We have between 2 and 10 million bacteria between fingertip and elbow
- Damp hands spread 1,000 times more germs than dry hands
- The number of germs on your fingertips doubles after you use the toilet
- Germs can stay alive on hands for up to three hours
- Millions of germs hide under watches and bracelets and there could be as many germs
under your ring as there are people in Europe (almost 1 billion)
Tests show that bacteria on a towel can grow from one to 2/3 million in a kitchen or washroom in
a matter of just four hours - to 1bn after 1 days normal use - to 10bn 2-3 days later and to 100bn
plus by the end of the week! Given that we wash hand towels once every week on average its
no wonder that hygienic hand drying is of such crucial importance in the promotion of good food
safety, health and personal hygiene.
Nitrate is one of the most common groundwater contaminants in rural areas. It is regulated in drinking
water primarily because excess levels can cause methemoglobinemia, or "blue baby" disease. Although nitrate
levels that affect infants do not pose a direct threat to older children and adults, they do indicate the possible
presence of other more serious residential or agricultural contaminants, such as bacteria or pesticides. Drinking
water containing high nitrate levels can affect the ability of our blood to carry oxygen.
Nitrate in groundwater originates primarily from fertilizers, septic systems, and manure storage or
spreading operations. Fertilizer nitrogen that is not taken up by plants or carried away by surface runoff leaches
to the groundwater in the form of nitrate. This not only makes the nitrogen unavailable to crops, but also can
elevate the concentration in groundwater above the levels acceptable for drinking water quality. Nitrogen from
manure similarly can be lost from fields, barnyards, or storage locations. Septic systems also can elevate
groundwater nitrate concentrations because they remove only half of the nitrogen in wastewater, leaving the
remaining half to percolate to groundwater.
In general, a water with a pH < 7 is considered acidic and with a pH > 7 is considered basic. The normal
range for pH in surfacewater systems is 6.5 to 8.5 and for groundwater systems 6 to 8.5. Alkalinity is a measure
of the capacity of the water to resists a change in pH that would tend to make the water more acidic. The
measurement of alkalinity and pH is needed to determine the corrosivity of the water.
In general, a water with a low pH (< 6.5) could be acidic, soft, and corrosive. Therefore, the water could
leach metal ions such as iron, manganese, copper, lead, and zinc from the aquifer, plumbing fixtures, and piping.
Therefore, a water with a low pH could contain elevated levels of toxic metals, cause premature damage to metal
piping, and have associated aesthetic problems such as a metallic or sour taste, staining of laundry, and the
characteristic "blue-green" staining of sinks and drains . The primary way to treat the problem of low pH water is
with the use of a neutralizer. A typical neutralizing chemical is soda ash. Neutralizing with soda ash increases
the sodium content of the water (water softening).
Water with a pH > 8.5 could indicate that the water is hard. Hardwater does not pose a health risk, but can
cause aesthetic problems. These problems include: formation of a "scale" or precipitate on piping and fixtures
causing water pressures and interior diameter of piping to decrease; causes an alkali taste to the water and can
make coffee taste bitter; formation of a scale or deposit on dishes, utensils, and laundry basins; difficulty in
getting soaps and detergents to foam and formation of insoluble precipitates on clothing, etc.; and decreases
efficiency of electric water heaters.
Phosphorous is usually present in natural waters as phosphate (PO-4-P). Phosphate has two different
forms in our environment: organic phosphate, which is a part of living plants and animals, their by-products and
their remains; and inorganic phosphate which can be bound to soil particles or present in laundry detergents.
Phosphorous is an essential element for life, an important nutrient for plants to grow and for metabolic
reactions of plants and animals. The number of aquatic plants growing in a particular area is dependent on the
amount of phosphorous available. In an aquatic ecosystem, inorganic phosphate is rapidly taken up by algae and
larger plants, resulting in algal blooms, increased biochemical oxygen demand and significant impacts on water
Phosphorous from natural resources, such as forest fires and fallout from volcanic eruptions, is
insignificant when compared to human-caused enrichments of water from nutrients such as phosphorous.
Phosphorous is introduced into the environment from human activities such as: human and animal wastes,
fertilizers, industrial wastes and human disturbance of the land and its vegetation.
Because phosphorous acts as a plant nutrient, it also causes eutrophication. Eutrophication is the
enrichment of water with nutrients, usually phosphorous and nitrogen, which stimulates the growth of algal
blooms and rooted aquatic vegetation. Eutrophication promotes more plant growth and decay, which in turn
increases biochemical oxygen demand. Phosphates in excess amounts can have a significant impact on water
Copper is a metal found in natural deposits as ores containing other elements. It is widely used in
household plumbing materials. Since copper contamination generally occurs from corrosion of household copper
pipes, it cannot be directly detected or removed by the water system. Instead, EPA is requiring water systems to
control the corrosiveness of their water if the level of copper at home taps exceeds an Action Level. Short-
and long-term effects: Copper is an essential nutrient, required by the body in very small amounts. However,
EPA has found copper to potentially cause the following health effects when people are exposed to it at levels
above the Action Level. Short periods of exposure can cause gastrointestinal disturbance, including nausea and
vomiting. Use of water that exceeds the Action Level over many years could cause liver or kidney damage.
People with Wilsons disease may be more sensitive than others to the effect of copper contamination and should
consult their health care provide.
Have you ever gone swimming and noticed that you could smell the water? That smell is chlorine. Water
may contain bacteria (germs) and other micro-organisms that can make us sick. Because chlorine kills bacteria,
we add it to swimming pools. We add it to drinking water for the same reason, only in lesser amounts.
Chlorine has been added to our water supplies since 1908. Prior to that, people frequently fell ill from
microorganisms, such as cholera and typhoid, in the water. With the use of chorine, these serious illnesses have
nearly dissappeared in the United States.
While chorine is important in keeping our water supplies safe to drink, it is poisonous and can be bad for
other organisms. Free chlorine (chlorine gas dissolved in water) is toxic to fish and aquatic organisms, even in
very small amounts. (See table below.) However, its dangers are relatively short-lived compared to the dangers
of most other highly poisonous substances. That is because chlorine reacts quickly with other substances in
water and forms combined chlorine, or dissipates as a gas into the atmosphere. The free chlorine test measures
only the amount of free or dissolved chlorine in water. The total chlorine test measures both free and combined
forms of chlorine. When the free chlorine combines with contaminants, such as oils, swimmer waste and other
organic compounds, it becomes combined chlorine.
Less than one-half (0.5) mg/L of free chlorine is needed to kill bacteria in drinking water. This is not
enough to cause the water to have an unpleasant taste or smell. Most people can't detect the presence of
chlorine in water at double (1.0 mg/L) that amount. Although 1.0 mg/L chlorine is not harmful to people, it does
cause problems for fish if they are exposed to it for a long time. This is a major consideration when keeping fish
in a home aquarium.
Effects of Chlorine on Fish and Aquatic Organisms
Amount of Total
Effects on Fish and Aquatic Organisms
(in milligrams per
0.006 Kills trout fry ("baby" trout) in two days
Recommended maximum for all fish and aquatic life. Kills
Chinook Salmon and Coho Salmon
0.01 - 0.05 Oysters have difficulty pumping water through their bodies
0.02 Maximum level Brook and Brown trout can withstand
Maximum amount that can be tolerated by young Pacific
Salmon in the Ocean
0.1 Kills most marine plankton
0.25 Only the hardiest fish can survive
0.37 Maximum fish can tolerate
1.0 Kills oysters
1. Like many things in life, the use of chlorine involves "trade-offs" or a combination of the good and bad.
What is the GOOD part of using chlorine in our drinking water?
What is the BAD part of using chlorine in our drinking water?
2. Would MORE or LESS (circle one) chlorine be needed in a swimming pool than in drinking water? Why?
(Hint: Think about how a swimming pool is used.)
3. What is the best way to reduce coliform bacteria?
4. Does your home have copper pipes? How would you know?
5. What is better to use to wipe your hands: dish towel or a paper towel? Why?
6. How can you raise the pH of your house water?
7. Name two sources of excessive phosphates in water.
8. Name two sources of excessive nitrates in water.
9. Name one thing that YOU can do to reduce water contamination.