1,1-Dichloroethylene

1,1,1,-Trichloroethane

1,1,2-Trichloroethane

1,2-Dichloropropane

2,4,5-TP (Silvex)

Acrylamide

Alachlor

Alpha emitters. Certain radioactive minerals that emit a form of radiation known as alpha radiation.  Some people who drink water containing alpha emitters in excess of EPA's standard over many years may have an increased risk of getting cancer.

Antimony

Asbestos

Atrazine

Barium

Benzene

Benzo(a)pyrene

Beryllium

Beta/photon emitters. Certain radioactive minerals that emit forms of radiation known as photons and beta radiation.  Some people who drink water containing beta and photon emitters in excess of EPA's standard over many years may have an increased risk of getting cancer.

Bromate. A salt or ion or bromic acid, which is a corrosive, colorless liquid used in making dyes and pharmaceuticals.  Some people who drink water containing bromate in excess of EPA's standard over many years may have an increased risk of getting cancer.

Cadmium

Carbofuran

Carbon tetrachloride

Chloramine. Any of several compounds containing nitrogen and chlorine.  Some people who drink water containing chloramines well in excess of EPA's standard could experience irritating effects to their eyes and nose; others could expereince stomach discomfort or anemia. 

Chlordane

Chlorine. A highly irritating poisonous gas, capable of combining with nearly all other elements.  Some people who drink water containing chlorine well in excess of EPA's standard could experience irritating effects to their eyes and nose; others could experience stomach discomfort. 

Chlorine dioxide. An explosive gas used chiefly in bleaching paper, starch, soap, and flour, and in purifying water.  Some infants and young children who drink water containing chlorine dioxide in excess of EPA's standard could experience nervous system effects.  Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of EPA's standard. Some people may experience anemia.

Chlorite. A generally green or black mineral that occurs in many rocks.  Some infants and young children who drink water containing chlorite in excess of EPA's standard could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of EPA's standard. Some people may experience anemia.

Chlorobenzene

Chromium

cis-1,2-Dichloroethylene

Coliform bacteria. A group of bacteria predominantly inhabiting the intestines of humans and animals, but also found in soil.  They 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 that distribute water and indicates that the water may be contaminated with germs that can cause disease. (DEQ Fact Sheet: pdf 41 kb, 1 page)

Combined radium 226/228. Radium is a luminescent, highly radioactive metallic element found in minute amounts in uranium ores.  It is used as a neutron source for some research purposes and was formerly used in cancer radiotherapy.  Some people who drink water containing radium 226 or 228 in excess of EPA's standard over many years may have an increased risk of getting cancer.

Copper

Cryptosporidium. A parasite that enters lakes and rivers through sewage and animal waste. It causes cryptosporidiosis, a mild gastrointestinal disease. However, the disease can be severe or fatal for people with severely weakened immune systems.

Cyanide

Dalapon

Di 2-ethylhexyl adipate

Di 2-ethylhexyl phthalate

Dibromochloropropane

Dichloromethane

Dinoseb

Dioxin (2,3,7,8-TCDD)

Diquat

E coli and fecal coliform. Bacteria whose presence indicates 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. 

Endothall

Endrin

Epichlorohydrin

Ethylbenzene

Ethylene dibromide

Fecal Coliform and E coli. Bacteria whose presence indicates 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. 

Fluoride. A compound many communities add to their drinking water to promote dental health. Some people who drink water containing fluoride in excess of the primary drinking water standard (4 milligrams per liter) over many years could get a bone disease. Young children (under 9) who drink water above a secondary standard (2 milligrams per liter) may develop brown staining and/or pitting of their permanent teeth.  This problem occurs only in developing teeth, before they emerge from the gums. 

Giardia lamblia. A parasite that enters lakes and rivers through sewage and animal waste. It causes gastrointestinal illness (e.g. diarrhea, vomiting, cramps).

Glyphosate

Haloacetic acids. A chemical compound that can occur in chlorinated water as a result of a reaction between organic materials in the water and chlorine added as a disinfectant.  Some people who drink water containing haloacetic acids in excess of EPA's standard over many years may have an increased risk of getting cancer.

Heptachlor

Heptachlor epoxide

Hexachlorobenzene

Hexachlorocyclopentadiene

Lead. A soft, dense metallic element historically used in containers, pipes, paints, etc. that typically leaches into water from plumbing in older buildings. Lead pipes and plumbing fittings have been banned since August 1998. Children and pregnant women are most susceptible to lead health risks.

Lindane

Mercury

Methoxychlor

MTBE. A fuel additive, commonly used in the United States to reduce carbon monoxide and ozone levels caused by auto emissions. Due to its widespread use, reports of MTBE detections in the nation's ground and surface water supplies are increasing.

Nitrate

Nitrite

ortho-Dichlorobenzene

Oxamyl (Vydate)

para-Dichlorobenzene

PCBs (Polychlorinated biphenyls)

Pentachlorophenol

Picloram

Radium (combined radium 226/228). Radium is a luminescent, highly radioactive metallic element found in minute amounts in uranium ores.  It is used as a neutron source for some research purposes and was formerly used in cancer radiotherapy.  Some people who drink water containing radium 226 or 228 in excess of EPA's standard over many years may have an increased risk of getting cancer.

Radon. A gas that can dissolve and accumulate in underground water sources, such as wells, and in the air in your home. Breathing radon can cause lung cancer. Drinking water containing radon presents a risk of developing cancer. Radon in air is more dangerous than radon in water.

Selenium

Silvex (2,4,5-TP)

Simazine

Styrene

Tetrachloroethylene

Thallium

Toluene

Toxaphene

trans-1,2-Dicholoroethylene

Trichloroethylene

Trihalomethanes (total trihalomethanes). A chemical compound that can occur in chlorinated water as a result of reaction between organic materials in the water and chlorine added as a disinfectant. 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.

Turbidity. The "cloudiness" of water due to the presence of suspended particles (dirt).  Turbidity alone has no health effects. However, turbidity can interfere with disinfection 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.

Vinyl chloride

Xylenes