EPA Regulated Contaminants

Microorganisms
Contaminant MCLG1(mg/L)2 MCL orTT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above the MCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Cryptosporidium zero TT3 Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Human and animal fecal waste
Giardia lamblia zero TT3 Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Human and animal fecal waste
Heterotrophic plate count (HPC) n/a TT3 HPC has no health effects; it is an analytic method used to measure the variety of bacteria that are common in water. The lower the concentration of bacteria in drinking water, the better maintained the water system is. HPC measures a range of bacteria that are naturally present in the environment
Legionella zero TT3 Legionnaire’s Disease, a type of pneumonia Found naturally in water; multiplies in heating systems
Total Coliforms (including fecal coliform and E. Coli) zero 5.0%4 Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 Coliforms are naturally present in the environment; as well as feces; fecal coliforms andE. coli only come from human and animal fecal waste.
Turbidity n/a TT3 Turbidity is a measure of the cloudiness of water. It is used to indicate water quality and filtration effectiveness (such as whether disease-causing organisms are present). Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria. These organisms can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. Soil runoff
Viruses (enteric) zero TT3 Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Human and animal fecal waste

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Disinfection Byproducts
Contaminant MCLG1(mg/L)2 MCL orTT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above the MCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Bromate zero 0.010 Increased risk of cancer Byproduct of drinking water disinfection
Chlorite 0.8 1.0 Anemia; infants and young children: nervous system effects Byproduct of drinking water disinfection
Haloacetic acids (HAA5) n/a6 0.0607 Increased risk of cancer Byproduct of drinking water disinfection
Total Trihalomethanes (TTHMs) –> n/a6 –> 0.0807 Liver, kidney or central nervous system problems; increased risk of cancer Byproduct of drinking water disinfection

Disinfectants
Contaminant MCLG1(mg/L)2 MCL orTT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above the MCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Chloramines (asCl2) MRDLG=41 MRDL=4.01 Eye/nose irritation; stomach discomfort, anemia Water additive used to control microbes
Chlorine (as Cl2) MRDLG=41 MRDL=4.01 Eye/nose irritation; stomach discomfort Water additive used to control microbes
Chlorine dioxide (as ClO2) MRDLG=0.81 MRDL=0.81 Anemia; infants and young children: nervous system effects Water additive used to control microbes

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Inorganic Chemicals
Contaminant MCLG1(mg/L)2 MCL or TT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above the MCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Antimony 0.006 0.006 Increase in blood cholesterol; decrease in blood sugar Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder
Arsenic 0 0.010 as of 01/23/06 Skin damage or problems with circulatory systems, and may have increased risk of getting cancer Erosion of natural deposits; runoff from orchards, runoff from glass and electronicsproduction wastes
Asbestos (fiber > 10 micrometers) 7 million fibers per liter (MFL) MFL Increased risk of developing benign intestinal polyps Decay of asbestos cement in water mains; erosion of natural deposits
Barium 2 2 Increase in blood pressure Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits
Beryllium 0.004 0.004 Intestinal lesions Discharge from metal refineries and coal-burning factories; discharge from electrical, aerospace, and defense industries
Cadmium 0.005 0.005 Kidney damage Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints
Chromium (total) 0.1 0.1 Allergic dermatitis Discharge from steel and pulp mills; erosion of natural deposits
Copper 1.3 TT7; Action Level=1.3 Short term exposure: Gastrointestinal distressLong term exposure: Liver or kidney damagePeople with Wilson’s Disease should consult their personal doctor if the amount of copper in their water exceeds the action level Corrosion of household plumbing systems; erosion of natural deposits
Cyanide (as free cyanide) 0.2 0.2 Nerve damage or thyroid problems Discharge from steel/metal factories; discharge from plastic and fertilizer factories
Fluoride 4.0 4.0 Bone disease (pain and tenderness of the bones); Children may get mottled teeth Water additive which promotes strong teeth; erosion of natural deposits; discharge from fertilizer and aluminum factories
Lead zero TT7; Action Level=0.015 Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilitiesAdults: Kidney problems; high blood pressure Corrosion of household plumbing systems; erosion of natural deposits
Mercury (inorganic) 0.002 0.002 Kidney damage Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands
Nitrate (measured as Nitrogen) 10 10 Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. Runoff from fertilizer use; leaking from septic tanks, sewage; erosion of natural deposits
Nitrite (measured as Nitrogen) 1 1 Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. Runoff from fertilizer use; leaking from septic tanks, sewage; erosion of natural deposits
Selenium 0.05 0.05 Hair or fingernail loss; numbness in fingers or toes; circulatory problems Discharge from petroleum refineries; erosion of natural deposits; discharge from mines
Thallium 0.0005 0.002 Hair loss; changes in blood; kidney, intestine, or liver problems Leaching from ore-processing sites; discharge from electronics, glass, and drug factories

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Organic Chemicals
Contaminant MCLG1(mg/L)2 MCL orTT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above theMCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Acrylamide zero TT8

Nervous system or blood problems; increased risk of cancer

Added to water during sewage/wastewater treatment
Alachlor zero 0.002

Eye, liver, kidney or spleen problems; anemia; increased risk of cancer

Runoff from herbicide used on row crops
Atrazine 0.003 0.003

Cardiovascular system or reproductive problems

Runoff from herbicide used on row crops
Benzene zero 0.005

Anemia; decrease in blood platelets; increased risk of cancer

Discharge from factories; leaching from gas storage tanks and landfills
Benzo(a)pyrene (PAHs) zero 0.0002

Reproductive difficulties; increased risk of cancer

Leaching from linings of water storage tanks and distribution lines
Carbofuran 0.04 0.04

Problems with blood, nervous system, or reproductive system

Leaching of soil fumigant used on rice and alfalfa
Carbon tetrachloride zero 0.005

Liver problems; increased risk of cancer

Discharge from chemical plants and other industrial activities
Chlordane zero 0.002

Liver or nervous system problems; increased risk of cancer

Residue of banned termiticide
Chlorobenzene 0.1 0.1

Liver or kidney problems

Discharge from chemical and agricultural chemical factories
2,4-D 0.07 0.07

Kidney, liver, or adrenal gland problems

Runoff from herbicide used on row crops
Dalapon 0.2 0.2

Minor kidney changes

Runoff from herbicide used on rights of way
1,2-Dibromo-3-chloropropane (DBCP) zero 0.0002

Reproductive difficulties; increased risk of cancer

Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards
o-Dichlorobenzene 0.6 0.6

Liver, kidney, or circulatory system problems

Discharge from industrial chemical factories
p-Dichlorobenzene 0.075 0.075

Anemia; liver, kidney or spleen damage; changes in blood

Discharge from industrial chemical factories
1,2-Dichloroethane zero 0.005

Increased risk of cancer

Discharge from industrial chemical factories
1,1-Dichloroethylene 0.007 0.007

Liver problems

Discharge from industrial chemical factories
cis-1,2-Dichloroethylene 0.07 0.07

Liver problems

Discharge from industrial chemical factories
trans-1,2-Dichloroethylene 0.1 0.1

Liver problems

Discharge from industrial chemical factories
Dichloromethane zero 0.005

Liver problems; increased risk of cancer

Discharge from drug and chemical factories
1,2-Dichloropropane zero 0.005

Increased risk of cancer

Discharge from industrial chemical factories
Di(2-ethylhexyl) adipate 0.4 0.4

Weight loss, liver problems, or possible reproductive difficulties.

Discharge from chemical factories
Di(2-ethylhexyl) phthalate zero 0.006

Reproductive difficulties; liver problems; increased risk of cancer

Discharge from rubber and chemical factories
Dinoseb 0.007 0.007

Reproductive difficulties

Runoff from herbicide used on soybeans and vegetables
Dioxin (2,3,7,8-TCDD) zero 0.00000003

Reproductive difficulties; increased risk of cancer

Emissions from waste incineration and other combustion; discharge from chemical factories
Diquat 0.02 0.02

Cataracts

Runoff from herbicide use
Endothall 0.1 0.1

Stomach and intestinal problems

Runoff from herbicide use
Endrin 0.002 0.002

Liver problems

Residue of banned insecticide
Epichlorohydrin zero TT8

Increased cancer risk, and over a long period of time, stomach problems

Discharge from industrial chemical factories; an impurity of some water treatment chemicals
Ethylbenzene 0.7 0.7

Liver or kidneys problems

Discharge from petroleum refineries
Ethylene dibromide zero 0.00005

Problems with liver, stomach, reproductive system, or kidneys; increased risk of cancer

Discharge from petroleum refineries
Glyphosate 0.7 0.7

Kidney problems; reproductive difficulties

Runoff from herbicide use
Heptachlor zero 0.0004

Liver damage; increased risk of cancer

Residue of banned termiticide
Heptachlor epoxide zero 0.0002

Liver damage; increased risk of cancer

Breakdown of heptachlor
Hexachlorobenzene zero 0.001

Liver or kidney problems; reproductive difficulties; increased risk of cancer

Discharge from metal refineries and agricultural chemical factories
Hexachlorocyclopentadiene 0.05 0.05

Kidney or stomach problems

Discharge from chemical factories
Lindane 0.0002 0.0002

Liver or kidney problems

Runoff/leaching from insecticide used on cattle, lumber, gardens
Methoxychlor 0.04 0.04

Reproductive difficulties

Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestock
Oxamyl (Vydate) 0.2 0.2

Slight nervous system effects

Runoff/leaching from insecticide used on apples, potatoes, and tomatoes
Polychlorinated biphenyls (PCBs) zero 0.0005

Skin changes; thymus gland problems; immune deficiencies; reproductive or nervous system difficulties; increased risk of cancer

Runoff from landfills; discharge of waste chemicals
Pentachlorophenol zero 0.001

Liver or kidney problems; increased cancer risk

Discharge from wood preserving factories
Picloram 0.5 0.5

Liver problems

Herbicide runoff
Simazine 0.004 0.004

Problems with blood

Herbicide runoff
Styrene 0.1 0.1

Liver, kidney, or circulatory system problems

Discharge from rubber and plastic factories; leaching from landfills
Tetrachloroethylene zero 0.005

Liver problems; increased risk of cancer

Discharge from factories and dry cleaners
Toluene 1 1

Nervous system, kidney, or liver problems

Discharge from petroleum factories
Toxaphene zero 0.003

Kidney, liver, or thyroid problems; increased risk of cancer

Runoff/leaching from insecticide used on cotton and cattle
2,4,5-TP (Silvex) 0.05 0.05

Liver problems

Residue of banned herbicide
1,2,4-Trichlorobenzene 0.07 0.07

Changes in adrenal glands

Discharge from textile finishing factories
1,1,1-Trichloroethane 0.20 0.2

Liver, nervous system, or circulatory problems

Discharge from metal degreasing sites and other factories
1,1,2-Trichloroethane 0.003 0.005

Liver, kidney, or immune system problems

Discharge from industrial chemical factories
Trichloroethylene zero 0.005

Liver problems; increased risk of cancer

Discharge from metal degreasing sites and other factories
Vinyl chloride zero 0.002

Increased risk of cancer

Leaching from PVC pipes; discharge from plastic factories
Xylenes (total) 10 10

Nervous system damage

Discharge from petroleum factories; discharge from chemical factories

Radionuclides
Contaminant MCLG1(mg/L)2 MCL orTT1(mg/L)2 Potential Health Effects from Long-Term Exposure Above theMCL (unless specified as short-term) Sources of Contaminant in Drinking Water
Alpha particles none7 ———- zero 15 picocuries per Liter (pCi/L) Increased risk of cancer Erosion of natural deposits of certain minerals that are radioactive and may emit a form of radiation known as alpha radiation
Beta particles and photon emitters
none7 ———- zero 4 millirems per year Increased risk of cancer Decay of natural and man-made deposits ofcertain minerals that are radioactive and may emit forms of radiation known as photons and beta radiation
Radium 226 and Radium 228 (combined) none7 ———- zero pCi/L Increased risk of cancer Erosion of natural deposits
Uranium zero 30 ug/L as of 12/08/03 Increased risk of cancer, kidney toxicity Erosion of natural deposits

Notes

Definitions:

    • Maximum Contaminant Level Goal (MCLG) – The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.
    • Maximum Contaminant Level (MCL) – The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.
    • Maximum Residual Disinfectant Level Goal (MRDLG) – The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.)
    • Treatment Technique (TT) – A required process intended to reduce the level of a contaminant in drinking water.
    • Maximum Residual Disinfectant Level (MRDL) – The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
    • 2 Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million (PPM).

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