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Naturally Occurring

Vermont’s bedrock contains naturally occurring elements such as uranium, iron, arsenic and manganese. Nitrate is a compound that occurs naturally in water in low background amounts, while fluoride is a naturally occurring mineral. 

These naturally occurring chemicals all have different characteristics and their relationship to human health differs. For example, fluoride, manganese and sodium benefit health as long as the amount ingested is not too high. Lead has no use in the human body. Copper is needed to make the body’s red blood cells, but too much can cause stomachaches, vomiting or diarrhea.

Drinking water is contaminated by naturally occurring chemicals in a variety of ways. Some wells may be contaminated because they are drilled into bedrock that contains a particular element such as arsenic. Sometimes high levels of a chemical occur in drinking water as a result of human activities. For example, arsenic could contaminate a well from agricultural or industrial practices, while lead typically enters drinking water from pipes, fittings and solder. High levels of nitrate in drinking water are usually caused by run-off from fertilized agricultural fields, septic system failures or compost piles.

Most health effects related to naturally occurring chemicals result when people drink contaminated water over a long period of time. Vermont Tracking includes data about four naturally occurring chemicals:  arsenic, nitrate, radium and uranium.

Arsenic

Arsenic is a natural element found in some rocks and soils in Vermont. You cannot smell or taste it. Arsenic can enter drinking water supplies either from natural deposits in the earth or from agricultural and industrial practices. Consuming drinking water contaminated with arsenic over long periods of time may increase the risk of developing bladder, lung and skin cancer. Research is also ongoing on arsenic's links to cardiovascular disease, diabetes and other cancers. The current maximum contaminant level (MCL) for arsenic in drinking water is 10 micrograms per liter (ug/L), which is equal to 10 parts per billion (ppb).

Nitrate

Nitrate exists naturally in water, but nitrate contamination of water is usually related to fertilized agricultural fields, septic system failures or compost piles that are too close to wells. There are two health concerns when drinking water that has high levels of nitrate. The first health concern is with young infants being put at risk of “blue baby syndrome” (also called methemoglobinemia). Infants can be poisoned from drinking formula made with nitrate-contaminated tap water. The second health concern with nitrate in drinking water is the formation of chemicals called nitrosamines in the digestive tract. Nitrosamines are currently being studied for their links to cancer. The current maximum contaminant level (MCL) for nitrate in drinking water is 10 milligrams per liter (mg/L), which is equal to 10 parts per million (ppm). 

Radium

Radium is a naturally occurring radioactive metal. Its most common isotopes (atomic forms) are radium-226, radium-224 and radium-228. Radium occurs at low levels in many environmental samples, especially in rocks, soils and water. A person who drinks water that contains high levels of radium over many years may be at increased risk for aplastic anemia as well as cancers, including leukemia, bone cancer and lymphoma. The current maximum contaminant level (MCL) for radium in drinking water is 5 picoCuries per liter (5 pCi/L).

Uranium

Uranium is a naturally occurring radioactive element. Uranium breaks down (decays) very slowly into other elements, including radium and radon gas. Drinking water may contain uranium in areas where it is present in the rocks and soil. A person who drinks water that contains high levels of uranium over many years may be at increased risk for kidney damage and cancer. The current Vermont Drinking Water Standard for uranium is 20 micrograms per liter (ug/L), which is equal to 20 parts per billion (ppb).

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Disinfection Byproducts

Most public water systems use a disinfectant to kill viruses and bacteria that can cause illness, such as gastrointestinal disorders or diarrhea. Chlorine is the most commonly used disinfectant, sometimes used in combination with other disinfectants, such as ozone, chloramine, chlorine dioxide and ultraviolet light. 

Disinfection byproducts (DBPs) are a family of chemicals formed when disinfectants react with naturally occurring organic matter and other substances in the source water. The levels of disinfection byproducts depend upon the nature of the source water, the type of treatment to remove particles and organic matter, and the type and concentration of disinfectant.

The risk of illness from disinfection byproducts is much lower than the risk of illness from drinking most surface water and some groundwater sources that have not been disinfected. The major health risks from DBPs result from long-term exposures.

Surface water sources such as reservoirs and streams are more likely to have higher disinfection byproduct levels than disinfected groundwater sources. If you get your drinking water from a private drinking water well, disinfection byproducts are unlikely to be present in the water.

EPA rules require water systems to improve treatment methods to minimize the formation of disinfection byproducts. The aim is to have a treatment method that uses enough disinfectant to protect consumers from waterborne disease while at the same time producing as few DBPs as possible.

Vermont Tracking includes data about two disinfection byproducts: haloacetic acids, known as HAA5 (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid) and the trihalomethanes (chloroform, bromodichloromethane, bromochloromethane and bromoform).

Haloacetic Acids (HAA5)

Haloacetic acids (HAA5) occur in drinking water when naturally occurring organic material in the water reacts with chlorine or chloramine used to disinfect the water. Consuming drinking water containing total haloacetic acids in excess of the maximum contaminant level (MCL) over many years may increase the risk of cancer. The current MCL for HAA5 is 60 micrograms per liter (ug/L), which is equal to 60 parts per billion (ppb).

Total Trihalomethanes (TTHM)

Total Trihalomethanes (TTHM) occur in drinking water when naturally occurring organic material in the water reacts with chlorine or chloramine used to disinfect the water. Consuming drinking water containing TTHM in excess of the maximum contaminant level (MCL) over many years may lead to an increased risk for liver, kidney and central nervous system problems, as well as an increased risk for cancer. The current MCL for TTHM is 80 micrograms per liter (ug/L), which is equal to 80 parts per billion (ppb).

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Man-made

Man-made chemicals get into drinking water as a result of human activities. An herbicide can be spread too close to a well or other water supply. An accidental chemical spill can contaminate a water source. Improper disposal of chemicals down storm and household drains or down the toilet can cause contamination. Contamination can also occur at old manufacturing sites where chemicals were disposed of improperly. As with naturally occurring chemicals, most health effects result when people drink water contaminated with man-made chemicals over a long period of time. Vermont Tracking includes data about four man-made chemicals: atrazine, di(2-ethylhexyl) phthalate (DEHP), tetrachloroethylene (PCE) and trichloroethylene (TCE).

Atrazine

Atrazine is an herbicide that is widely used as a weed killer. Although its uses were greatly restricted in 1993, it can still be in the environment. People who drink water that contains high levels of atrazine over many years may be at greater risk for cardiovascular problems and reproductive difficulties. The maximum contaminant level (MCL) for atrazine is 3 micrograms per liter (ug/L), which is equal to 3 parts per billion (ppb).

Di(2-ethylhexyl) phthalate (DEHP)

Di(2-ethylhexyl) phthalate (DEHP) is the most commonly used of a group of related chemicals called phthalates or phthalic acid esters. The greatest use of DEHP is as a plasticizer (softener) for polyvinylchloride (PVC) and other polymers including rubber, cellulose and styrene. A number of packaging materials and tubings used in the production of foods and beverages are PVC contaminated with phthalic acid esters, primarily DEHP. Some people who drink water containing DEHP in excess of the maximum contaminant level (MCL) over many years may be at greater risk for liver problems, reproductive difficulties and cancer. The current MCL for DEHP in drinking water is 6 micrograms per liter (ug/L), which is equal to 6 parts per billion (ppb).

Tetrachloroethylene (PCE)

Tetrachloroethylene (PCE) is a solvent used in the textile industry and as a component of aerosol dry-cleaning products. It can enter water systems through discharges from factories and dry-cleaning facilities. Consuming drinking water with high levels of PCE over many years may increase the risk for liver problems and cancer. The current maximum contaminant level (MCL) for PCE is 5 micrograms per liter (ug/L), which is equal to 5 parts per billion (ppb).

Trichloroethylene (TCE)

Trichloroethylene (TCE) is a solvent that is primarily used to remove grease from fabricated metal parts and is also used in the production of some textiles. Consuming drinking water that contains high levels of TCE for many years may lead to increased risk for liver problems and cancer. The current maximum contaminant level (MCL) for TCE is 5 micrograms per liter (ug/L), which is equal to 5 parts per billion (ppb).

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