Water is essential to life, and people drink water every day. Americans enjoy some of the safest drinking water in the world. About ninety percent of Americans get their drinking water from public sources (sometimes called “Community Water Systems”). Over ninety contaminants in public drinking water are regulated by states and the U.S. EPA. Every year Community Water Systems send their customers a “Consumer Confidence Report’ which contains information about the quality of water. It includes information on where the water comes from, how it is treated, a list of the chemicals they test for, and the highest concentration of each chemical that they found in the past year.
The National and Maryland Tracking Networks contain information only on Community Water Systems because information on private wells is not available.
Drinking Water and Health
Contaminants in drinking water are of concern to the public’s health because many people can be exposed to them, especially from large Community Water Systems. Contaminants in drinking water can be either natural or man-made. People can be exposed to contaminants in drinking water not only by drinking the water, but also by eating foods prepared with the water, breathing water droplets or chemicals released from the water while showering, or by absorbing chemicals through their skin while bathing.
Some drinking water contaminants of special interest are nitrates, disinfection by-products, arsenic and lead. These contaminants are tracked separately in both the National and Maryland Tracking Networks because they are more likely to occur at higher levels.
Arsenic is a toxic chemical element that is naturally found in the Earth’s crust in soil, rocks, and minerals. There is a wide variation in the levels of arsenic found in drinking water systems and private water supplies across the Nation. In 2001 the U.S. EPA lowered the drinking water standard for arsenic to 10 parts per billion. Some people who drink water containing arsenic in excess of EPA’s standard over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.
Disinfection byproducts are formed when chlorine and other disinfectants react with naturally occurring organic matter in the source water. The levels of disinfection byproducts can vary with distance and season of the year, in addition to the type of disinfectant and water treatment. High exposures over many years may increase the risk of bladder, rectal, and colon cancer as well as the possibility of reproductive and birth defects.
Lead can be found in all parts of the environment. The greatest exposures are from paint, dust and soil around old houses, and from lead-contaminated toys. The most likely source of lead in a home’s drinking water is from the plumbing. Lead can cause serious health problems if too much enters your body from drinking water or other sources. It can cause damage to the brain and kidneys, and can interfere with the production of red blood cells that carry oxygen to all parts of your body.
The greatest risk of lead exposure is to infants, young children, and pregnant women. Scientists have linked the effects of lead on the brain with lower IQ scores in children. Adults, especially with kidney problems and high blood pressure can be affected by low levels of lead.
Nitrate and nitrite are related substances that can be converted to each other. Nitrate is the form commonly found in water, often in areas where nitrogen-based fertilizers are used. Vegetables, food, and meat are the major sources of nitrate exposure. The greatest use of nitrates is as a fertilizer.
In the body, nitrate converts to nitrite. Nitrite interferes with the oxygen-carrying capacity of blood. Symptoms (shortness of breath and blueness of the skin) can occur rapidly over a period of days. Infants below the age of six months who drink water containing over 1 mg/L nitrite, or 10 mg/L nitrate, could become seriously ill, and, if untreated, may die. This is normally not a concern with Community Water Systems.
Drinking Water in Maryland
In 2007, Maryland had 486 Community Water Systems serving a minimum of 25 residents, 559 Non-Transit Non-Community Water Systems (schools, day care nurseries, nursing homes), and 2,488 Transit Non-Community Water Systems (highway rest stops, service stations, restaurants, etc). The Maryland Department of the Environment regulates Community Water Systems, and the others are inspected by local health departments. About sixteen percent of Marylanders get their drinking water from private wells, higher than the national average. These wells are tested for only a few contaminants such as turbidity, nitrate and bacteria, when the wells are first drilled and whenever the property changes hands thereafter.
What You Can Do
If you are on a Community Water System, make sure you get the annual Consumer Confidence Report and report any possible problems to your water system. If you are on a private well, get your water tested regularly. Contact your local health department for information on certified testing laboratories. If you have concerns about the purity of your drinking water, you may want to consider special treatment at the point of use. These treatment systems can remove most of the contaminants, but must be properly maintained for optimal use.
If you are on a private well and your baby has trouble breathing or turns blue, go to an emergency room immediately.