Common water contaminants


Turbidity has no health effects. However, turbidity can interfere with disinfection because the particles can act as shields for viruses and bacteria and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

Fecal Coliform and E coli are bacteria whose presence indicate that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. 

Cryptosporidium is a parasite that enters lakes and rivers through sewage and animal waste. This microbe has an outer shell that allows it to survive outside the body for long periods of time which makes it tolerant to many chlorine disinfectants. It causes cryptosporidiosis, a mild gastrointestinal disease. However, the disease can be severe or fatal for people with severely weakened immune systems.

Giardia lamblia is a parasite that enters lakes and rivers through sewage and animal waste. It causes gastrointestinal illness (e.g., diarrhea, vomiting, cramps). Giardia, like cryptosporidium, can survive long periods of time outside the body and is also difficult to treat with just basic chlorine disinfectants.

Coliform bacteria are common in the environment and are generally not harmful. However, the presence of these bacteria in drinking water is usually a result of a problem with the treatment system or the pipes which distribute water. This indicates that the water may be contaminated with germs that can cause disease.

Coliform Bacteria and Water Quality

What are coliforms? Coliforms are bacteria are always present in the digestive tracts of animals, including humans, and are found in their wastes. They are also found in plant and soil material. The most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Total coliform counts give a general indication of the sanitary condition of a water supply.

Total coliforms include bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste.

Fecal coliforms are the group of the total coliforms that are considered to be present specifically in the gut and feces of warm-blooded animals.

Because the origins of fecal coliforms are more specific than the origins of the more general total coliform group of bacteria, fecal coliforms are considered a more accurate indication of animal or human waste than the total coliforms.

(E.coli) is the major species in the fecal coliform group. Of the five general groups of bacteria that comprise the total coliforms, only E. coli is generally not found growing and reproducing in the environment. Consequently, E. coli is considered to be the species of coliform bacteria that is the best indicator of fecal pollution and the possible presence of pathogens.

Coliforms are relatively easy to identify, are usually present in larger numbers than more dangerous pathogens, and respond to the environment, wastewater treatment and water treatment similarly to many pathogens. As a result, testing for coliform bacteria can be a reasonable indication of whether other pathogenic bacteria are present.

If pathogenic (disease-causing) organisms are present, they may be passed as well. When a stream is polluted by fecal material, pathogenic bacteria, viruses, and parasites may be introduced, posing a health hazard to those who come in contact with the water. Municipal and rural water supplies can transmit human diseases such as cholera (Vibrio cholerae), typhoid fever (Salmonella typhi), salmonellosis (Salmonella), and gastroenteritis.

The threat of such disease transmission becomes more serious as the population density increases and more sewage pollutes public water supplies, carrying with its human intestinal pathogens.

If fecal coliform counts are high (over 200 colonies per 100 ml of water sample) in the river or stream, there is a greater chance that pathogenic organisms are also present. A person swimming in such water has a greater chance of getting sick from swallowing disease-causing organisms, or from pathogens entering the body through cuts in skin, the nose, mouth, or the ears. Diseases and illnesses such as typhoid fever, hepatitis, gastroenteritis, dysentery, and ear infections can be contracted in waters


(Antimony, Asbestos, Barium, Beryllium, Cadmium, Chromium, Copper, Cyanide, Lead, Mercury, Nitrate/Nitrite, Selenium and Thallium)

Arsenic is a highly toxic heavy metal. Some people who drink water containing arsenic in excess of EPA's standard over many years could experience a wide range of serious problems. Health concerns include damage to the bladder, lungs, heart, kidney and liver. Arsenic can also harm the central & peripheral nervous system and circulatory system. Arsenic exposure has been linked to several types of cancers.

Fluoride; EPA has set an enforceable drinking water standard for fluoride of 4 mg/L (some people who drink water containing fluoride in excess of this level over many years could get bone disease, including pain and tenderness of the bones). EPA has also set a secondary fluoride standard of 2 mg/L to protect against dental fluorosis. Dental fluorosis, in its moderate or severe forms, may result in a brown staining and/or pitting of the permanent teeth. This problem occurs only in developing teeth, before they erupt from the gums. Children under nine should not drink water that has more than 2 mg/L of fluoride.

Lead typically leaches into water from plumbing in older buildings. Children and pregnant women are most susceptible to lead health risks.


Disinfectant chemicals normally added to the water to kill germs such as giardia and e coli.

Chlorine; Some people who are using water containing chlorine in excess could experience irritating effects to their eyes and nose as well as stomach discomfort.

Chlorine Dioxide is a water additive used to control taste and odor in water. Some infants and young children who drink water containing chlorine dioxide in excess of EPA's standard could experience nervous system effects as well as anemia. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of EPA's standard.


Disinfection byproducts form when disinfectants added to drinking water to kill germs react with naturally-occurring organic matter in water.

Total Trihalomethanes. Some people who drink water containing trihalomethanes in excess of EPA's standard over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting cancer.


Organic contaminants include pesticides, herbicides, decayed plant and animal tissues, gasoline (centuries old decayed plant and animal tissue), and plasticizers (made from petroleum products).  Plasticizers leach out of plumbing lines, fittings and storage tanks, so ironically, the purification system itself can contaminate the water if it is not properly constructed. Organic levels are measured in ppb or ppm or TOC (Total Organic Carbon). Organics are removed using a combination of Activated Carbon, Ultrafiltration, Reverse Osmosis and Ozone Injection.


Volatile organic compounds (VOCs) are organic chemicals that have a very low boiling point. Oftentimes, below the freezing point of water.

Some VOCs are naturally occurring, like those released from plants.  Other VOCs are emitted by manmade products, such as paints and lacquers, paint strippers, cleaning supplies, disinfecting products, cosmetics, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions. Fuels such as gasoline contain VOCs as well.

When VOCs are spilled or improperly disposed of, they may soak into the ground. VOCs, like water, follow gravity, and leach into the ground with rain, possibly reaching municipal water supplies and private wells.

The primary route of exposure to VOCs is through inhalation. However, VOCs can be ingested through food and water.

Because there are so many types of VOCs, potential health effects are varied.

According to the EPA, exposure to VOCs can cause eye, nose, and throat irritation; headaches, loss of coordination, nausea; damage to liver, kidney, and central nervous system. Some VOCs are suspected or known to cause cancer in humans. Key signs or symptoms associated with exposure to VOCs include conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, emesis, epistaxis, fatigue, dizziness.

Point-of-entry filtration systems that remove VOCs can be installed in the home to treat contaminated water providing safe water for drinking, cooking, bathing, and laundry.

Nitrates and Nitrites may be found in some public or private water supplies. It may cause health problems if found in amounts greater than the health standard set by the Environmental Protection Agency (EPA).

Nitrates and nitrites are nitrogen-oxygen chemical units which combines with various organic and inorganic compounds. Once taken into the body, nitrates are converted into nitrites. The greatest use of nitrates is as a fertilizer.

The health effects; Short-term: Excessive levels of nitrate in drinking water have caused serious illness and sometimes death. The serious illness in infants is due to the conversion of nitrate to nitrite by the body, which can interfere with the oxygen-carrying capacity of the child’s blood. This can be an acute condition in which health deteriorates rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin while Long-term: Nitrates and nitrites have the potential to cause diuresis, increased starchy deposits and hemorrhaging of the spleen.

Most nitrogenous materials in natural waters tend to be converted to nitrate, so all sources of combined nitrogen, particularly organic nitrogen and ammonia, should be considered as potential nitrate sources. Primary sources of organic nitrates include human sewage and livestock manure.

Nitrates and Nitrites are very soluble and do not bind to soils, nitrates have a high potential to migrate to ground water. Because they do not evaporate, nitrates/nitrites are likely to remain in water until consumed by plants or other organisms.