Public Water Systems in the United States provide drinking water that is among the highest quality in the world. However, drinking water contains some contaminants at low levels and can become contaminated at higher levels of pollutants.
Drinking water quality is an important public health issue because contamination in a single system can expose many people at once. People can be exposed to contaminants in drinking water by
- drinking the water
- eating foods prepared with the water
- breathing water droplets or chemicals released from the water while showering
- absorbing chemicals through their skin while washing
The majority of community water systems meet all health-based water quality standards. Therefore, the risk of disease from drinking water supplied by a community water system is low.
However, exposure to contaminants in drinking water can cause many adverse effects, some of which can be immediate with symptoms occurring soon after drinking the water. An example is gastrointestinal illness. Other effects can develop over time, such as reproductive disorders, cancer, or neurological disorders.
Arsenic in Public Water and Health
Arsenic is a toxic chemical element that is found naturally in the Earth's crust in soil, rocks, and minerals. The levels of arsenic found in drinking water systems and private water supplies across the United States vary widely. The maximum contaminant level (MCL) for Arsenic is 10 mcg/L.
Exposure and Risk
The majority of health risks from arsenic in the United States are from long term exposures. Although short-term exposures to high doses may cause adverse effects in people, a high dose of arsenic is about a thousand times higher than the drinking water standard. Arsenic exposures do not occur from EPA-regulated public water supplies in the United States that comply with the arsenic MCL.
Possible health effects include:
- thickening and discoloration of the skin
- stomach pain
- nausea
- vomiting
- diarrhea
- liver effects
- cardiovascular (heart) effects
- pulmonary (lung) effects
- immunological (ability to fight infections) effects
- neurological (brain) effects such as numbness and partial paralysis
- reproductive effects
- endocrine effects such as diabetes and
- cancer
- bladder
- lungs
- skin
- kidney
- nasal passages
- liver and
- prostate
Prevention
Public Water Systems are already being tested for arsenic. If you think your drinking water is contaminated, call your water supplier or state drinking water program. You can locate these agencies or find information on drinking water in general from EPA's Safe Drinking Water Hotline at (800) 426-4791.
In Iowa, if you use a private well, you can contact a local county sanitarian and have your water tested for arsenic. Otherwise, contact an environmental laboratory in your area and have your water tested for arsenic for a small fee.
Di(2-ethylhexyl) Phthalate (DEHP) in Public Water and Health
Di(2-ethylhexyl) phthalate (DEHP) is a man-made chemical. DEHP is not toxic at the low levels usually present in the environment. Exposure to DEHP is generally very low. The maximum contaminant level (MCL) for DEHP is 6 mcg/L.
Exposure and Risk
Exposure to DEHP is generally very low. Increased exposures may come from intravenous (IV) fluids delivered through plastic tubing, and from eating or drinking contaminated foods or water. DEHP is usually present at very low levels in the following:
- Medical products packaged in plastic such as blood products
- Some foods packaged in plastics, especially fatty foods like milk products, fish or seafood, and oils
- Well water near waste sites
- Workplace air or indoor air where DEHP is released, but usually not at levels of concern
- Fluids from plastic IV tubing if used extensively, such as for kidney dialysis
Most of what we know about the health effects of DEHP comes from studies of rats and mice given high amounts of DEHP. In animals, high levels of DEHP damaged the liver and kidney and affected their ability to reproduce. Whether or not DEHP contributes to human kidney damage is unclear.
The U.S. Environmental Protection Agency has set the MCL for DEHP at 6µg/L. Some people who drink water containing DEHP over the MCL for many years may have problems with their liver, could experience reproductive difficulties, and may have an increased risk of getting cancer.
Prevention
Community Public Water Systems are already being tested for DEHP, and are required to provide that information each year to consumers in the Consumer Confidence Report. It is almost impossible to completely avoid DEHP because it is commonly found in plastics. Prevent babies and small children from chewing on plastic objects that are not toys.
Haloacetic Acids in Public Water and Health
Haloacetic Acids are a family of chemicals formed when disinfectants used to kill viruses and bacteria in community water supplies react with naturally occurring organic matter and other substances in the source water. The risk of illness from haloacetic acids is much lower than the risk of illness from drinking most surface water and some groundwater sources that have not been disinfected.
Haloacetic Acids include five related chemicals and have a combined maximum contaminant level (MCL) of 60 mcg/L:
- trichloroacetic acid
- dichloroacetic acid
- monochloroacetic acid
- dibromoacetic acid
- monobromoacetic acid
Exposure and Risk
When people consume haloacetic acids at high levels over many years, they increase their risk of developing bladder cancer. Other health effects that may be associated with haloacetic acids include rectal and colon cancer, and adverse developmental and reproductive effects during pregnancy. They have been studied with mixed results; however, the weight of evidence of the health effects data suggests a potential association.
There are several ways that haloacetic acids can get into your body.
- Ingestion (through your mouth): drinking water with haloacetic acids
- Inhalation (through your nose): Some haloacetic acids can be released into the air in your home when you use your tap water. This can happen when you are taking a shower or washing dishes. The hotter the water is, the more likely it is that haloacetic acids will be released into the air. Haloacetic acids can also get into the air when you boil your tap water, such as when you make tea or soup.
- Dermal (through your skin): You can be exposed to haloacetic acids when your skin comes into direct contact with water, like when you are bathing or showering. But for most people, only very small amounts of haloacetic acids get into the body through the skin. However, much higher levels of haloacetic acids can get in your body when your contact time with water increases. This can happen if you typically take long baths or swim frequently in public pools.
Prevention
Community Public Water Supplies are already being tested for haloacetic acids, and are required to provide that information each year to consumers in the annual Consumer Confidence Report. If your Public Water System has notified you of a haloacetic acids violation, it does not mean that the people who consume the system's water will become sick.
The U.S. Environmental Protection Agency (EPA) requires that water systems use treatment methods to reduce the formation of haloacetic acids and to protect people from waterborne disease and the potential harmful effects of haloacetic acids.
Nitrate in Public Water and Health
Nitrate and nitrite are nitrogen-oxygen molecules that can combine with many organic and inorganic compounds. Nitrate is the form commonly found in water, often in areas where nitrogen-based fertilizers are used. The greatest use of nitrate is as a fertilizer. Infants are at greatest risk for illness from exposure to high levels of nitrate. The maximum contaminant level (MCL) for nitrate is 10 mg/L.
Exposure and Risk
Infants under the age of 6 months who drink water containing more than 1 mg/L nitrite, or 10 mg/L nitrate, could become seriously ill and, if untreated, may die. In the body, nitrate changes to nitrite. Nitrite interferes with the oxygen-carrying capacity of blood, so the oxygen you breathe in doesn't get distributed throughout the body. Symptoms, such as shortness of breath and blueness of the skin, can occur rapidly over a period of days. Read more about Nitrate from the CDC.
Infants are at greatest risk for illness from exposure to high levels of nitrate.
- 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 gets worse rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin.
- Long-term: Researchers continue to explore if there are associations with long-term exposures to nitrate, including adverse reproductive effects and some cancers. The studies are not conclusive at this time, and health standards are focused on protecting infants.
Prevention
Nitrate is monitored at least once a year in every public water supply. If the test result is above half of the MCL the system is sampled quarterly; if the result is at 10.0 mg/L, the system is sampled monthly for at least one year. If the system has a potential to form nitrite, in Iowa, the system is required to conduct additional monitoring at the entry point to the distribution system as well as in the distribution system to ensure that the nitrite levels remain below the MCL of 1.0 mg/L at all times.
The following treatment methods have been approved by the EPA for removing nitrate/nitrite:
- ion exchange
- reverse osmosis
- electro dialysis
Both nitrate and nitrite are acute contaminants. If the levels of nitrate or nitrite exceed their Maximum Contaminant Levels, the system must notify the public within 24 hours via newspapers, radio, TV, and other means. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.
Radium in Public Water and Health
Radium is a naturally occurring radioactive metal that can exist in several forms. Radium is present at very low levels in rocks and soil and may strongly attach to those materials. Everyone is exposed to low levels of radium in the air, water, and food. EPA has set a drinking water limit of 5 picocuries per liter (5pCi/L) for radium-226 and radium-228 combined.
Exposure and Risk
Everyone is exposed to low levels of radium in the air, water, and food. Additionally,
- Higher levels may be found in the air near industries that burn coal or other fuels.
- It may be found at higher levels in drinking water from wells.
- Miners, particularly miners of uranium and hard rock, are exposed to higher levels of radium.
- It may also be found at radioactive waste disposal sites.
There is no clear evidence that long-term exposure to radium at the normal environmental level is likely to result in harmful health effects. However, exposure to higher levels of radium over a long period of time may result in harmful effects including anemia, cataracts, fractured teeth, certain cancers (especially bone cancer), and death.
The U.S. Environmental Protection Agency (EPA) and the National Academy of Sciences Committee on Biological Effects of Ionizing Radiation have stated that radium is a known human carcinogen (cancer causing agent).
Prevention
Community Public Water Supplies are already being tested for radionuclides, and are required to provide that information each year to consumers in the annual Consumer Confidence Report. EPA strongly encourages people to learn more about their drinking water, and to support local efforts to protect and upgrade the supply of safe drinking water.
Tetrachloroethene (PCE) in Public Water and Health
Tetrachloroethene (PCE), also known as perchloroethylene, tetrachloroethylene, and perchloroethene, is a man-made, colorless, dense liquid. The maximum contaminant level (MCL) for PCE is 5 mcg/L.
Exposure and Risk
In the past, PCE was used in large amounts to produce other chemicals and as an industrial solvent. It was also used to clean and degrease metals and used in paints and pesticides. Less toxic chemicals are now available to replace this solvent. Large-scale commercial production of PCE has stopped, although some production still occurs.
PCE is not life threatening unless people intentionally or accidentally drink more than a few spoonfuls at one time or spill a large amount so that they breathe it and get it on their skin. Breathing concentrated fumes of PCE (enough so that its sickeningly sweet smell is noticed) can rapidly cause fatigue, vomiting, dizziness, and possibly unconsciousness. Most people recover from these effects once they are in fresh air.
Breathing, drinking, or having PCE come into contact with skin may cause liver damage, stomach aches, or dizziness if people are exposed long enough to high amounts. The health effects on people from long-term exposure to small amounts of PCE are not known.
Most people are not expected to be exposed very much to PCE because the levels are usually very low in the environment and it is no longer used by the general public. Higher levels of PCE have been found in groundwater at a few locations in the United States. Individuals who use or drink the groundwater from these locations may have higher exposures to PCE. People who live near hazardous waste sites and industrial buildings where PCE is used may be exposed to this chemical by breathing in contaminated air, touching contaminated soil, or drinking contaminated water.
In addition to exposures in air and drinking water, people may be exposed to PCE from accidents or normal operations in workplaces. The compound has been used as a solvent for many operations. People involved in such work are most likely to be exposed by breathing in vapors of the chemical or from skin contact.
Prevention
Community Public Water Supplies are already being tested for PCE and other solvents, and are required to provide that information each year to consumers in the annual Consumer Confidence Report. If a doctor finds that a patient has been exposed to substantial amounts of PCE, that doctor should ask whether any children in the household might also have been exposed. The doctor might need to ask the state health department to investigate.
Families are not likely to be exposed to amounts of PCE that are high enough to be a health concern because the chemical is no longer used in household products. It is possible that some old household products (such as cleaners, degreasers, and paints) contain small amounts of PCE. These products should be kept out of reach of children.
Trichloroethene (TCE) in Public Water and Health
Trichloroethene (TCE), which is also known as trichoroethylene, is a synthetic chemical. TCE can be found in soil and water, particularly at hazardous waste sites. The chemical can leach through soil and into groundwater. The maximum contaminant level (MCL) for trichloroethene is 5 mcg/L.
Exposure and Risk
TCE had many industrial and household uses. In industry, it was widely used to remove oil or grease from manufactured parts. In the home, it was an ingredient of products such as spot cleaners, glues, and aerosol sprays. Since January 1, 2002, TCE is no longer manufactured for domestic use in the United States because it affects the ozone layer.
According to EPA, some persons who consume water containing excess amounts of TCE over many years may experience problems with their livers and may have an increased risk of cancer.
Prevention
Community Public Water Supplies are already being tested for TCE and other solvents, and are required to provide that information each year to consumers in the annual Consumer Confidence Report. If a doctor finds that a patient has been exposed to substantial amounts of TCE, the doctor should ask whether any children in the household might also have been exposed. The doctor might need to ask the state health department to investigate.
Children can be exposed to TCE in household products, such as glues and cleaners that were manufactured before 2002. Parents should store household chemicals out of reach of young children to prevent accidental poisonings or skin irritation. Household chemicals should always be stored in their original labeled containers. Household chemicals should never be stored in containers that children would find attractive to eat or drink from, such as old soda bottles. People should keep the Poison Control Center number (1-800-222-1222) near the phone.
Sometimes, older children sniff household chemicals in an attempt to get high. Children may be exposed to TCE by inhaling products containing it. Parents should talk with their children about the dangers of sniffing chemicals.
Trihalomethanes in Public Water and Health
Trihalomethanes are a family of chemicals formed when disinfectants used to kill viruses and bacteria in community water supplies react with naturally occurring organic matter and other substances in the source water. The risk of illness from trihalomethanes is much lower than the risk of illness from drinking most surface water and some groundwater sources that have not been disinfected.
Trihalomethanes include four related chemicals and have a combined maximum contaminant level (MCL) of 80 mcg/L:
- chloroform
- bromodichloromethane
- dibromochloromethane
- bromoform
Exposure and Risk
When people consume trihalomethanes at high levels over many years, they increase their risk of developing bladder cancer. Other health effects that may be associated with trihalomethanes include rectal and colon cancer, and adverse developmental and reproductive effects during pregnancy. They have been studied with mixed results; however, the weight of evidence of the health effects data suggests a potential association.
There are several ways that trihalomethanes can get into your body.
Prevention
Community Public Water Supplies are already being tested for trihalomethanes, and are required to provide that information each year to consumers in the annual Consumer Confidence Report. If your Public Water System has notified you of a trihalomethanes violation, it does not mean that the people who consume the system's water will become sick.
The U.S. Environmental Protection Agency (EPA) requires that water systems use treatment methods to reduce the formation of trihalomethanes and to protect people from waterborne disease and the potential harmful effects of trihalomethanes.
- Ingestion (through your mouth): drinking water with trihalomethanes
- Inhalation (through your nose): Some trihalomethanes can be released into the air in your home when you use your tap water. This can happen when you are taking a shower or washing dishes. The hotter the water is, the more likely it is that trihalomethanes will be released into the air. Trihalomethanes can also get into the air when you boil your tap water, such as when you make tea or soup.
- Dermal (through your skin): You can be exposed to trihalomethanes when your skin comes into direct contact with water, like when you are bathing or showering. But for most people, only very small amounts of trihalomethanes get into the body through the skin. However, much higher levels of trihalomethanes can get in your body when your contact time with water increases. This can happen if you typically take long baths or swim frequently in public pools.
Uranium in Public Water and Health
Uranium is a naturally and commonly occurring radioactive element. Because uranium is found everywhere in small amounts, people always take it into the body from the air, water, food, and soil. In most areas of the United States, low levels of uranium are found in the drinking water. Higher levels may be found in areas with elevated levels of naturally occurring uranium in rocks and soil. The maximum contaminant level (MCL) for uranium in drinking water is 30 mcg/L.
Exposure and Risk
Because uranium is found everywhere in small amounts, people are always exposed from the air, water, food, and soil. In most areas of the United States, low levels of uranium are found in the drinking water. Higher levels may be found in areas with elevated levels of naturally occurring uranium in rocks and soil.
The chemical effects of uranium in drinking water are of greater concern than the possible effects of its radioactivity. Bathing and showering with water that contains uranium is not a health concern.
People who work at factories that process uranium, work with phosphate fertilizers, or live near uranium mines have a chance of taking in more uranium than most other people. Larger-than-normal amounts of uranium might also enter the environment from erosion of tailings from mines and mills for uranium and other metals. Accidental discharges from uranium processing plants are possible, but these compounds spread out quickly into the air.
Prevention
Community Public Water Supplies are already being tested for uranium and other radionuclides, and are required to provide that information each year to consumers in the annual Consumer Confidence Report.