Nitrate, Bacteria Cause for Public Concern

The most common contaminants found in drinking water are coliform bacteria, nitrates, calcium, iron and mangenese.

 The first two can be health risks, while the last two are considered "aesthetic risks" only. They are objectionable because of color and odor, but do no real harm. Not all contaminants make water unsafe to drink. Water that contains no contaminants can normally only be obtained by extensive treatment.

The U.S. Environmental Protection Agency (EPA) has established Maximum Contaminant Levels (MCLs) for various contaminants. Water that contains contaminants below the MCL is generally considered safe to drink.

While water quality in municipal wells is regulated by state and federal standards, water quality in private wells is not. Owners of a private water supply are responsible for ensuring that their water supply is safe. The most common health-related contaminants found in private wells are bacteria and nitrate. The only way to know if your water contains harmful bacteria or high levels of nitrate is to have it tested.

Bacteria

Bacteria can be hazardous to health. Some sources of bacterial pollution include runoff from feedlots, pastures and other land areas where animal wastes are deposited, and the discharge from septic tanks and sewage treatment facilities.
Coliform bacteria are the indicator organisms used to determine whether water meets the standard established for drinking water.

Any presence of coliform bacteria indicates that the water system don't meet the established standard. The coliform bacteria may not necessarily produce disease, but can indicate the presence of other bacteria, which may cause infections, hepatitis, typhoid fever and other illnesses.

Nitrate-nitrogen

Nitrate-nitrogen is a basic part of the environment and is essential for living things. It is the nutrient most used for growing crops.

However, excessive concentrations of nitrate-nitrogen can be hazardous to human and animal health. Nitrate-nitrogen in groundwater may come from sewage disposal systems and livestock facilities, from fertilized cropland or from naturally occurring sources of nitrogen.

The EPA has set a maximum safety level of 10 milligrams of nitrate-nitrogen per liter as the MCL for public water systems.

The main health hazard from nitrate-nitrogen results when nitrate is reduced to nitrite in the digestive system. Nitrite reduces the ability of the blood to carry oxygen and can result in "blue baby syndrome" in newborns. Pregnant women and infants should drink water that contains less than 10 mg of nitrate-nitrogen.

Adults are less sensitive to nitrate and can tolerate a higher level of nitrate. However, little is known about the possible long-term effects of drinking high nitrate content water. A potential cancer risk from nitrate (and nitrite) in water and food has been reported. The magnitude of the risk of cancer from nitrate in drinking water isn't known.