water quality and system

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Lead - Similar to copper, lead enters water supplies through acidic decomposition of water piping, particularly in old buildings where lead was used as the piping material. In addition, many copper and cast iron pipe systems were joined with lead or solder with a high lead content. The lead elements break down in mild acidic water and mix with the drinking water. Lead concentrates in the body and its effects are cumulative. Lead is a known cancer risk, has adverse kidney and nervous system effects and is especially toxic to infants. Unfortunately, studies for lead contamination by the U.S. EPA in the late 1980s revealed that up to 20 percent of the nation's water was contaminated with lead.

Elimination of lead and copper can be accomplished by treatment, usually by adding chemicals to the water to reduce the acidity to deter the corrosive action.

Other Metals - Zinc, aluminum and iron are not currently regulated but have recommended maximum levels. Health effects are minimal but they can give water metallic taste or unfavorable color.

Mercury, once thought to be inert because it does not mix with water, was discovered concentrated in shellfish on the edges of large industrial areas. Mercury causes nervous disorders.

Inorganic Compounds - Metals such as antimony, nickel and beryllium are covered in the standards under the inorganic compounds because their presence can cause kidney or liver effects. In addition, nitrite and nitrates are regulated because these minerals have been shown to affect the blood/oxygen cycle in infants. This problem is called "blue baby syndrome." Finally, asbestos is regulated under inorganic compounds because it has been shown be a cancer risk for lung tumors.

Radionuclides

In some systems, trace elements of radon, radium, uranium and other radioactive materials are present. These traces are very small but still detectable by sophisticated laboratory techniques. All are suspected to pose a cancer risk. The amounts that can be present in a safe water supply is still being debated. A draft standard is proposed, but it has not yet been made a legal requirement.

Organic Compounds

Another category of water impurity that affects drinking water

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Living Impurities

In a drinking water supply, the presence of cells indicates the tolerance in the water supply for living microorganisms.

Cells, which are extremely large compared to water molecules, live in all water systems. The membrane of the cell wall is tough enough to withstand the dissolving action of the water molecule. But chlorine, which has been added to water supplies for the past 150 years or so, reacts with the cell wall. In a simplified explanation, all a chlorine molecule has to do is touch a cell and the tough outer membrane of the cell is broken. Then the water molecules can break through into the cell and destroy it.

Not all cells in water are harmful, and in the case of wastewater treatment, a certain type of bacteria is used to break down the impurities and ultimately purify the water. In general, all cells are referred to here as microorganisms. Cells that cause disease and sickness are call pathogens.

Drinking water purification experts and the industry have long used an "indicator" organism to aid in the test for water impurities. This is because the test for a true germ that poses a health risk, if positive, would mean it was already too late for the public official to take any action. For example, if Vibrio cholerae (the microorganism that causes cholera) were found in water supply samples taken at the tap, a health warning would arrive too late since the contaminated water would have already been used by some number of the population. In the case of pathogens, the worst risk comes from fecal coliforms contaminating a drinking water supply.

E. Coli

E. Co/i, short for Escherichia coli, is used as a measure of the potential harmful bacteria in water supplies. The E. coli bacteria is chosen as the indicator because it is consistently present in human feces in large numbers, and it has the same survivability in water as more pathogenic organisms. The test for E. coli is fairly simple and a simplified diagram for its test is shown in Figure 8-3. Another common test method uses an enzyme that changes color if the coliforms are present. If the coliforms are of the E. coli variety, the enzyme color fluoresces. Kits of this type are available from specialized laboratories. Follow all instructions and necessary safety precautions.

In the past, there have been coliforms found as a result of growth on the inside of water supply piping. These coliforms, while not the

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Figure 8-4.

Electron microscope photograph of a full-grown Giardia lamblia. Courtesy: Visuals Unlimited, New Hampshire. Reprinted from Microbiology: An Introduction with permission

of Benjamin/Cummings Publishing Co., Inc.

result of human consumption, have led to some boil water orders in community supplies. Called biofilm, these coliforms have not been confirmed to be hazardous to public health. It is important to separate the presence of total coliforms from E. coli and to have data on coliforms resulting from growth inside water supply piping.

Chlorine is the main chemical used to treat water supplies and to eliminate coliforms. Since the pattern of coliforms is similar to other cells that are true disease-causing germs (pathogens), chlorine neutralization is effective in removing the pathogens as well.

Viruses

Similar to coliforms, viruses are carried in the wastes of humans and animals; however, they are neutralized by chlorine in much the same way as coliforms. Therefore, the tests for E. coli are used as an indicator for the removal of viruses and most other pathogens.

Giardia - Increasingly difficult to detect using E. coli as an indicator organism and more difficult to kill than coliforms, the cysts of the Giardia lamblia grow into a tiny one-celled animal that uses a sucker to attach itself to the intestinal cell wall. Persons infected

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Figure 8-5.

Electron microscope photograph showing the oocysts of the Cryptosporidium parvum microorganism. Courtesy: Diagnostic Medical Parasitology, L.S. Garcia and D.A. Bruckner, ©American Society of Microbiologists.

with microorganism have the disease giardiasis, a prolonged diarrhea-causing disease that results in nausea, weakness, weight loss and abdominal cramps. A picture of the grown protozoa is shown in Figure 8-4. About seven percent of the total population carries the microorganism and sheds the cysts in their feces.

The laboratory procedure for Giardia lamblia is a complex fluorescent antibody test.

Cryptosporidium

Like Giardia, Cryptosporidium is shed in the feces of humans and animals. In the environment this microorganism forms a protective cap to protect itself. The encased protozoa is called an oocyst (pronounced oh oh cyst.) A photograph of the oocysts is shown in Figure 8-5. Like other protozoa, only one type of the animal is known to infect humans. This type is called Cryptosporidium parvum. C. parvum are active in surface waters, and in shallow wells subject to

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contamination from surface waters.

Individuals infected with C. parvum have the disease cryptosporidiosis which is characterized by nausea, vomiting, fever, diarrhea, headache and loss of appetite. This disease often passes within two weeks or less and most normal individuals recover fully in that time.

At the present time, unfortunately, there is no standard for the number of oocysts allowed in a water supply, although the government is moving fast to try to have one established. Right now, the recommended standard is zero oocysts per 100 milliliter sample, but health professionals believe an action level should be set a between 30 and 50 oocysts per liter. The current test for C. parvum is the fluorescent antibody test similar to the one for

G. lambia.

Like the Giardia cysts, the Cryptosporidium oocysts are extremely difficult to kill using chlorine and as a result, recommended treatment for water systems consists of filtration. The size of both the giardia and crypto cysts exceed one micrometer and are removed by filtering water below that size.

Legionella

Unlike the Giardia and Cryptosporidium which form cysts in raw and treated water, the Legionella pneumophilia bacteria infects individuals by airborne contamination along with ingestion through drinking water. The bacteria cause Legionnaires' disease, a severe pneumonia. The source is usually not the drinking water supply but rather the humidity in the air conditioning system.

L. pneumophilia grows in cooling towers in the presence of dirt and mud but the bacteria is unique because it grows in tepid water instead of the usual supply of cold water. The bacteria is picked up in the air and carried to individuals along with the tiny water droplets. Evidence to date is not clear whether the bacteria are eradicated by chlorine but facility managers should take the precaution of treating water heating and cooling system waters with prepared biocides according to manufacturer's recommendations and using all necessary safety precautions. In some cases, the application of hypochlorite (liquid bleach) will adequately kill populations of L. pneumophilia. The newspaper article in Figure 8-6 indicates what can happen to facilities that fail to manage their water supply and do not test for the presence of Legionella.

For more information about treating heating, ventilation and air conditioning systems for Legionella and other airborne bacteria, see Indoor Air Quality: A Guide for Facility Managers by Ed Bas, a

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companion volume in The Facilities Management Library.

Organisms

Larger than the broad class of microorganisms, larger animals are potentially encountered in water supplies. Larvae of insects and worms are found in surface water supplies but usually the mechanisms used to screen out turbidity screen out these larger organisms as well.

Safe Water

Suffice to say that regulatory standards for safe drinking water exist. The standards specify safe levels of the chemicals and microorganisms in water supplies. Each standard has a published test method that has been agreed upon by a consortium of medical professionals and scientists as the acceptable method to determine the amounts of impurities.

Laboratories

Each part of the book details a standardized test method to determine if impurities exist in the water. A facility manager who

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Figure 8-6 (continued).

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