An archive of water treatment and health information for a variety of contaminants and water quality issues. Most contaminants in the archive are rarely found at detectable levels in municipal water supplies, and many health issues associated with these contaminants are the result of extended exposure to very large amounts.
We offer this information for reference only. Having a high quality laboratory water test is the best way to diagnose most water issues.
Acidic water—water low in pH—can stain fixtures and damage copper plumbing. It can also disrupt many water treatment methods.
Acrylamide is a chemical compound used in a wide range of products and found in some starchy cooked foods and coffee. Exposure to large amounts can lead to blood and nervous system problems, and possibly cancer.
Alachlor is an herbicide used to control grasses and broadleaf weeds on row crops. Long-term exposure can have harmful effects on the liver, kidneys, spleen, eyes and blood, and it is a likely human carcinogen.
Aldicarb is a pesticide used on a wide range of crops to control nematodes and insects. It is highly toxic, causing cholinesterase inhibition—an enzyme suppression with several neurotoxic effects.
Aldrin and dieldrein are banned insecticides formerly used to control termites and ants. They are highly toxic to the liver and central nervous system, and may be carcinogenic.
Algae and cyanobacteria are microorganisms that can cause taste/odor issues. In still waters, they sometimes form colonies and release harmful cyanotoxins.
Alkalinity, the capacity of water to neutralize an acid, can play a role in adjusting the pH of water being treated.
Alum (aluminum sulfate) is a water clarifying agent used in municipal water treatment. It's not generally considered to be a health concern.
Aluminum, typically found as alum (aluminum sulfate) in drinking water, is a common metal that may be related to the development of Alzheimer's and other nervous system diseases.
Ametryn is an herbicide used on pineapple, corn and sugarcane crops. Long term exposure to large amounts may cause liver damage and decreased weight gain.
Ammonia is a natural gas produced by organic decay that can cause corrosion to copper plumbing.
Antimony is a toxic semi-metal used in a wide range of industries. Its toxic effects are similar to arsenic, and long-term exposure can lead to problems with blood sugar and cholesterol.
Arsenic is a poisonous semi-metal that occurs naturally in the environment and is used in a wide range of industries. Long term exposure can lead to cancer and other serious health problems.
Asbestos is a group of naturally occurring fibers found in a wide range of products. It is typically not a water treatment concern.
Atrazine is a widely used herbicide for the control of grasses and broadleaf weeds. Long-term exposure can lead to cardiovascular problems and reproductive difficulties.
Bacillus thuringiensis (Bt) are a group of bacteria that produce a protein toxic to many insects. They are considered harmless to mammals, but sometimes produce toxins that cause diahrea.
Bacteria are common in water. Most are non-pathogenic, harmless to human health. Some are responsible for diseases such as cholera, typhoid fever, hepatitis, dysentery, and gastroenteritis.
Barium is a lustrous metal used in the manufacture of a wide range of products. It's toxic to the central nervous system, and long-term exposure can lead to increases in blood pressure and heart disease.
Bentazon is an herbicide used on a wide range of crops. Studies of long term exposure in animals have shown changes in the heart, liver, kidneys and prostate.
Benzene is a volatile organic chemical used in manufacturing plastics and other synthetic products. It is a known carcinogen, and can lead to blood problems with long term exposure to large amounts.
Beryllium is an inorganic metal, used in nuclear reactors and the aerospace industry. Long term exposure to large amounts can cause intestinal lesions, and it is a known carcinogen by inhalation exposure.
BPA is a chemical used in the manufacture of polycarbonate plastics and epoxy resins, found in many consumer goods. It can act as a weak estrogen, and there is concern that it may have developmental effects.
Boron is a chemical element used in a wide range of industries, including manufacturing, power plants, fertilizers and pesticides. It is an essential nutrient, but can be toxic in large amounts.
Bromates are chemical compounds used in manufacturing and food production. In certain conditions they can form during water treatment involving ozone. They are toxic with acute exposure, and may be carcinogenic.
Bromide is an anion of bromine, found naturally in sea-water and some foods. It can complicate water chlorination and ozonation, and cause neurological effects with long term exposure to large amounts.
Cadmium is a metal commonly found in batteries and used in industrial and agricultural operations. Long term exposure could lead to kidney damage.
Carbaryl is an insecticide with a wide range of crop and residential uses. Exposure can cause cholinesterase inhibition—an enzyme suppression with several neurotoxic effects.
Carbuforan is a highly toxic insecticide, now banned in the United States. Long term exposure can lead to problems with the blood, nervous and reproductive systems.
Carbon dioxide is a chemical compound found in most natural waters. It is closely associated with pH.
Carbon tetrachloride is an organic chemical found in refrigerants (Freon®), cleaning products and fire extinguishers. It is a possible human carcinogen, and can lead to liver problems with long term exposure.
Chloral hydrate is a chemical used in insecticides, herbicides and as a hypnotic drug for the treatment of insomnia. Long term exposure can lead to liver changes, and it may be a carcinogen.
Chloramines are water disinfectants, resulting from the addition of ammonia to chlorine, that provoke continual controversy.
Chlordane is an insecticide once used to control a wide range of insects, now highly restricted. It is a potential human carcinogen, and can lead to liver problems with long-term exposure.
Chloride is an anion commonly found in water, often as sodium chloride—common table salt. It is an essential nutrient, but can affect the aesthetic quality of water or cause corrosion and pitting in plumbing.
Chlorine is the most commonly used water disinfectant. It can be an eye, skin and respiratory irritant, and water chlorination can sometimes form carcinogenic by-products.
Chlorite and chlorate are disinfection byproducts that can form in water treated with chlorine dioxide. Large amounts can have harmful effects on small children, and may lead to anemia with long term exposure.
Chloroacetones are chemicals that may form during water chlorination. Studies of chloroactones are limited, but they have been shown to be toxic to the liver in large doses.
Chlorobenzene is an organic compound with a wide range of uses in industry. Long term exposure to large amounts can lead to kidney and liver damage.
Chloropicrin is a chemical with a wide range of uses, most commonly as a pesticide ingredient. It is highly toxic, and can be fatal with exposure to large amounts.
Chlorotoluron is an herbicide used in Europe to control weeds that affect winter barley and wheat crops. It is of low acute toxicity, but long term exposure to large amounts has been shown to be carcinogenic to some mice.
Chlorpyrifos is an insecticide with a wide range of uses, mostly agricultural. Exposure can cause cholinesterase inhibition, an over-stimulation of the nervous system that, in high doses, can lead to paralysis or death.
Chromium exists in two forms—one an essential nutrient, the other a skin irritant and likely human carcinogen.
Water can take on color for a variety of reasons, most typically organic matter and decaying vegetation.
Copper is a natural metal used in plumbing and pesticides. Long-term exposure to excessive amounts can lead to liver and kidney problems.
Corrosion can lead to water discoloration, taste and odor issues, sediment and leaks.
Cryptosporidium is a group of microorganisms responsible for the disease cryptosporidiosis.
Cyanazine is a banned herbicide formerly used on corn crops. Long term exposure can cause liver changes and birth defects, and it is a possible human carcinogen.
Cyanide is a toxic chemical that can lead to nerve damage and thyroid problems with long-term exposure.
Cyanogen chloride is a chemical used in chemical warfare, tear gas, pesticide gases, and in the formation of other chemicals. It is highly toxic, with harmful effects on the brain, heart and lungs.
1,2-Dichloropropane (1,2-DCP) is an organic chemical used in manufacturing and agriculture. Exposure can affect the central nervous system, liver and kidneys, and may cause cancer.
1,3-Dichloropropene is a common pesticide used to control nematodes. It is toxic to the liver and intestines, can have long-term effects on the kidney and urinary bladder, and is a “probable human carcinogen.”
1,4-Dioxane is a chemical used in a wide range of industries as a solvent. Long term exposure can cause harmful effects on the nervous system, stomach, lungs, liver and kidneys, and it may be carcinogenic.
2,4-D (2,4-dichlorophenoxyacetic acid) is a widely used herbicide used on crops, lawns, pastures and forests. It's also used aquatically. Long term exposure can lead to liver, kidney and adrenal gland problems.
Dalapon is an herbicide used to control grassy weeds in crops, lawns and industry. It can cause kidney changes with long term exposure to large amounts.
DBCP (1,2-dibromo-3-chloropropane) is a soil fumigant used to control nematodes in a wide assortment of plants and vegetables. Exposure can lead to reproductive problems, and it's a possible human carcinogen.
DDT is an insecticide that was widely used from the 1940s until environmental concerns lead its ban in the early 1970s. Long term exposure can damage the liver, nervous and reproductive systems, and it is a likely carcinogen.
DEHA [Di(2-ethylhexyl) adipate] is an organic chemical used as a plasticizer in a wide range of products. Exposure can lead to weight loss, liver enlargement and potential reproductive issues.
DEHP [Di(2-ethylhexyl) phthalate] is a chemical used as a plasticizer in many products, including food packaging. It's a possible human carcinogen, and exposure lead to liver problems and reproductive difficulties.
Diazinon is an insecticide used to control a wide range of insects. It was once a common residential pesticide, but is now restricted to certain agricultural uses. Exposure can cause cholinesterase inhibition.
DCA is a chemical that can form as a by-product of water disinfection involving chlorine or chloramine. It can have harmful effects on the liver, reproductive and nervous systems, and it may be carcinogenic.
DCBs are chemicals used in a wide range of commercial and domestic products. Long term exposure can have harmful effects on the liver, blood, spleen and other organs, and may be carcinogenic.
Dichloroethanes are volatile organic chemicals frequently used in industry. Long term exposure to large amounts may be carcinogenic.
Dichloroethenes (1,1-Dichloroethylene, 1,2-Dichloroethylene) are organic compounds with a wide range of industrial uses. Long-term exposure to large amounts can cause liver damage.
Dichloromethane is an organic compound used in both industry and agriculture. Long term exposure can lead to liver problems and an increased risk of cancer.
Dicofol is an insecticide used to control mites on a wide range of crops. Long term exposure can affect the liver, kidneys, heart and adrenal glands.
Diflubenzuron is an insecticide used to control flies and mosquitoes. Long term exposure can have harmful effects on the blood, liver and spleen, and it can metabolize into a likely human carcinogen.
Dimethoate is an insecticide used in agriculture to control a wide range of insects. Exposure can cause cholinesterase inhibition—an enzyme suppression with several neurotoxic effects, and it may be carcinogenic.
Dinoseb is an herbicide used in soybean, vegetable and cereal crops. Long term exposure to large amounts can lead to reproductive difficulties.
Dioxin is a contaminant that occurs during the production of chlorinated organic compounds. Long term exposure can lead to reproductive difficulties and cancer.
Diquat is a commonly used herbicide. It is rarely found in water, but long term exposure can lead to cataracts.
Diuron is an herbicide used on a wide range of crops and non-agricultural areas. It is classified as a “known/likely” human carcinogen.
Edetic acid is a chemical used in a wide range of industries. Long-term exposure may lead to effects on growth rate, blood changes, dental erosion and reproductive problems, and may inhibit absorption of essential nutrients.
Endocrine disruptors are substanes that manipulate or block the body's natural chemical signals.
Endosulfan is an insecticide currently used on a wide range of crops. It's being phased out, and will soon be banned in the United States. It is highly toxic, causing cholinesterase inhibition.
Endothall is an herbicide, defoliant and desiccant (drying agent), used on a wide range of crops. Long term exposure may lead to stomach and intestinal problems.
Endrin is a toxic pesticide, once used on a wide range of crops but no longer in use in the United States. Long term exposure can cause liver damage.
Epichlorohydrin is an industrial chemical that can theoretically contaminate water during sediment treatment. Long term exposure may lead to stomach problems and cancer.
Ethylbenzene is an organic chemical used to make styrene (which is then used to make plastics). Long term exposure can lead to liver and kidney problems.
Ethylene dibromide (1,2-Dibromoethane) is a lead scavenging chemical used in leaded fuels and the chemical industry. It's also a carcinogen that can lead to problems with the stomach, liver, kidney and reproductive system.
Fenitrothion is an insecticide used worldwide on a wide range of crops, though it has limited use in the United States. It can cause cholinesterase inhibition—an enzyme suppression with several neurotoxic effects.
Fluoride is added to water in many communities as a method of promoting dental health. Excessive exposure can cause moderate to severe dental and skeletal conditions.
Formaldehyde is a chemical that can form as a by-product of water disinfection involving chlorine. Long term exposure to large amounts can lead to weight loss and damage to the digestive system.
Giardia lamblia is an intestinal parasite that causes the disease giardiasis, also known as “beaver fever” or “traveler’s diarrhea.”
Glyphosate is a widely used herbicide (commonly known under its trade name, Roundup®). Long term exposure to high concentrations can lead to kidney and reproductive problems.
Haloacetic acids are toxic chemicals that form as a result of water treatment chemicals reacting with organic particles or bromide. Some are potential human carcinogens.
Hardness is the amount of calcium and magnesium salts present in water. Hard water can have adverse effects on plumbing and cleaning surfaces.
Heptachlor is a highly restricted pesticide now used exclusively in buried electronics. Long term exposure can lead to liver damage and an increased risk of cancer.
Heterotrophic bacteria are naturally occurring and have no adverse effects on human health.
Hexachlorobenzene (HCB) is a disused fungicide, banned in the U.S. since 1965. Long term exposure to large amounts can lead to liver, kidney and reproductive difficulties, and may lead to an increased risk of cancer.
Hexachlorobutadiene (HCBD) is an industrial chemical that can form as a by-product during chlorine manufacturing. It can have harmful effects on the liver and kidneys, and it may be carcinogenic.
Hexachlorocyclopentadiene (HEX) is a chemical used in the manufacture of other chemicals, including pesticides. Long term exposure can lead to kidney or stomach problems.
Hydrogen sulfide is a naturally occurring gas that emits a “rotten egg” odor.
Iodine-131 is a radioactive particle produced by nuclear reactors. Exposure can interfere with the thyroid and lead to thyroid cancer.
Iron can lead to water discoloration, and in high amounts can create problems with residential or industrial water.
Iron bacteria—bacteria that oxidize iron—can cause staining and damage to plumbing.
Lead is a toxic metal, now banned but formerly used in a wide range of consumer products. Exposure can lead to kidney problems, high blood pressure, childhood disabilities and cancer.
Legionella are small, rod-shaped bacteria responsible for Pontiac Fever and Legionnaire's Disease, a type of pneumonia.
Lindane is a restricted insecticide used to control mites and fleas on pets and livestock. Long term exposure to high levels can lead to kidney and liver problems.
Magnesium is a natural element that affects the hardness of water.
Malathion is an insecticide that, though only mildly toxic, can metabolize into the enzyme-inhibiting chemical malaoxon, causing harmful nervous system effects.
Manganese is an essential mineral that, in high concentrations, can cause staining of fixtures and laundry.
MCPA (4-(2-methyl-4-chlorophenoxy)acetic acid) is an herbicide with a wide range of applications. It is moderately toxic and can lead to problems with growth, reproduction, and harmful effects on the liver and kidneys.
Mercury is a chemical element used in product manufacturing. Exposure can cause damage to the kidneys and central nervous system.
Methane is a natural gas commonly used in heating. It's flammable, and potentially explosive.
Methanol is a naturally occurring chemical with a wide range of industrial uses. Long term exposure can lead to vision problems and neurological damage.
Methoxychlor is a pesticide used as an alternative to DDT to control a wide range of pests. Long term exposure to large amounts can lead to problems with the reproductive system.
Methyl tertiary-butyl ether (MTBE) is a gasoline additive that may, in high doses, be a human carcinogen.
Metolachlor is an herbicide used on a wide range of crops and non-crop areas. It is mildly toxic, but can have long term effects on the liver, and it is a possible human carcinogen.
Molinate is a banned herbicide, formerly used on rice fields. Long term exposure can have harmful effects on the liver, kidneys, adrenal and thyroid glands.
Monochloroacetic acid is an industrial chemical that can form as a result of water disinfection. Long-term exposure to large amounts can lead to harmful effects on the heart, muscles and central nervous systems.
Mutagen X (also known as MX) is a toxic by-product of chlorination. Long term exposure to large amounts may increase risk of cancer.
Naphthalene is a common chemical, formerly used to produce mothballs. Long term exposure can cause cataracts, as well as liver and neurological damage.
NDMA (N-Nitrosodimethylanime) is a toxic chemical, released through chemical reactions in some water treatment methods. Exposure can lead to liver damage and cancer.
Nickel is a naturally occurring metal found in most water. It's generally harmless, but may produce allergic reactions.
Nitrates—commonly used in fertilizer—are generally not a health concern, but in high concentrations can cause methemoglobinemia, or “blue baby syndrome.”
Nitrilotriacetic acid is a chemical found in some laundry detergents. Exposure to large amounts for a long period of time can cause kidney damage, and it is a potential carcinogen.
Norovirus is a group of viruses that can cause gastronteritis, also known as “stomach flu.”
Taste and odor problems are caused by a variety of sources, usually rotting vegetation or disinfectants.
Oryzalin is an herbicide used primarily around fruit and nut trees. Long term exposure can lead to changes in blood, liver and kidneys, and it is a possible human carcinogen.
Oxamyl is a pesticide (trade name Vydate®) used to control a wide range of pests. Long term exposure to large amounts can cause problems with the central nervous system.
2-Phenylphenol is a microbicide used to sanitize foods and disinfect hospitals, farms and other environments. It is of low toxicity, but can have long-term effects on the bladder and liver, and may be carcinogenic.
Paraquat dichloride is an herbicide made famous in the 1970s when it was used to destroy marijuana crops in the U.S. and Mexico. It is highly toxic and can lead to lung, kidney and liver damage.
Parathion is a highly toxic insecticide, now banned in many countries. Long term exposure can lead to blood and liver damage, and possibly cancer.
Pendimethalin is an herbicide used to control broad-leaf and grassy weeds on crops and non-agricultural areas. Long-term exposure to large amounts may lead to liver damage.
Pentachlorophenol (PCP) is a fungicide used for wood preservation. Long term exposure to large amounts can lead to liver and kidney problems, and may lead to an increased risk of cancer.
PFAS are a group of manufactured chemicals used in a wide range of commercial products. Exposure may effect the liver or cause developmental problems, and PFAS are being studied for their possible carcinogenicity.
Perchlorate is a chemical commonly used by the defense industry to make rocket fuel and explosives. Long term exposure can lead to thyroid problems.
Permethrin is an insecticide with a wide range of residential and agricultural applications. It's only moderately toxic, but may lead to cancer with long-term exposure.
Pesticides are synthetic organic chemicals commonly used in agriculture that can have a variety of adverse health effects.
pH is a measure of the relation between the acidity and alkalinity of water.
Pharmaceuticals and personal care products (PPCPs) are ubiquitous, and can arrive in water through a number of pathways. Human health effects are largely unknown, but they can have a harmful ecological impact.
Phosphates are naturally occurring nutrients, commonly used as fertilizers. Phosphate pollution can lead to an overabundance of nutrients in water, disrupting the natural ecosystem.
Picloram is an herbicide used to control woody-plants and broad-leafed weeds. Long term exposure to large amounts can lead to liver problems.
Pirimiphos-methyl is an insecticide used on stored grains and cattle. Exposure to large amounts can cause cholinesterase inhibition—an enzyme suppression with several neurotoxic effects.
Polychlorinated biphenyls (PCBs) are banned organic chemicals, formerly used in a wide range of industrial and commercial products. Long term exposure that can lead to cancer and a wide range of health problems.
PAHs are a diverse group of chemicals produced almost exclusively through human activity. Long term exposure can lead to cancer and other harmful effects on the kidneys, liver, blood, immune and reproductive systems.
Propanil is an herbicide used primarily on rice crops. It can metabolize into more toxic chemicals, and have harmful effects on the spleen and liver with exposure to large amounts.
Pyriproxyfen is an insecticide used both residentially and in agriculture. Long term exposure to large amounts can cause liver and kidney problems.
Tetrachloroethene is an organic chemical commonly used in dry cleaning. Long term exposure can lead to liver problems and an increased risk of cancer.
Radon is a naturally occurring radioactive element found in most groundwater. Long term exposure can lead to an increased risk of cancer.
Selenium is a naturally occurring element and essential human nutrient. It's rarely a water pollutant and is only harmful in high concentrations.
Silica is commonly found in nature as sand or quartz. It can clog and scale water treatment equipment.
Silver is a naturally occurring element with bacteriostatic properties. It is typically an aesthetic rather than health concern.
Silvex is a banned herbicide, formerly used to control woody plants and broad-leafed weeds. Long term exposure can lead to liver problems.
Simazine is an herbicide used on a wide range of crop and non-crop areas. Long term exposure to large amounts can cause blood problems.
Spinosad is an insecticide derived from bacteria. It has a wide range of uses, including residential pet treatment and mosquito treatment for water containers. Long term exposure to high amounts may affect the liver and thyroid.
Styrene is a chemical commonly used in plastics manufacturing. Long term exposure can lead to liver, kidney and circulatory problems.
Sulfates are natural substances found in most waters, and as a byproduct of industrial waste and fertilizer runoff. They can have a laxative effect in high concentrations.
1,2,3-Trichloropropane is a chemical used both as an intermediate in, and formed as a by-product of chemical manufacturing. Long term exposure can cause liver and kidney damage, and it is a probable human carcinogen.
2,4,6-Trichlorophenol is a chemical that can form as a by-product of water disinfection involving chlorine or bleach. Long term exposure can cause harmful effects on the liver and blood, and it is a probable human carcinogen.
Temephos is an insecticide used to control mosquito larvae. Exposure to large doses can affect the central nervous system.
Terbuthylazine (TBA) is an algaecide/microbiocide used in industrial cooling systems and ornamental fountains. Though only moderately toxic, it may cause anorexia and other health effects with long term exposure.
Tetrachloroethanes are industrial chemicals with limited modern use. Exposure to large amounts can cause central nervous system, respiratory and liver damage, and they are potentially carcinogenic.
Thallium is a highly toxic metal found in trace amounts in copper, lead, zinc and other ores. Long term exposue can lead to blood pressure, gastrointestinal, kidney and liver problems.
Toluene is a chemical used industrially as a solvent and in the manufacture of further chemicals. Long term exposure cause problems with the central nervous system, kidneys and liver.
TDS is a measure of the combined content of all substances contained in a liquid in a molecular suspended form.
Toxaphene is a banned pesticide that can cause cancer, kidney, liver and thyroid problems with long term exposure.
Trichloroacetic acid is used in various industries, and may form as a result of water disinfection involving chlorine. It is a possible human carcinogen.
TCBs are organic chemicals with a wide range of industrial uses. They're moderately toxic, and can lead to glandular problems with long term exposure.
TCEs are organic chemicals used industrially as solvents. Long term exposure can affect the kidneys, liver, nervous, circulatory and immune systems.
Trichloroethene (TCE) is an industrial solvent and an ingredient in paints and paint strippers. Long term exposure can cause liver problems, and it is a possible carcinogen.
Triclosan is a pesticide widely use in consumer hygiene products and cosmetics. Its harmful effects on aquatic life make it an environmental concern, and long term exposure may be harmful to muscle tissue in mammals.
Trifluralin is an herbicide with a wide range of agricultural and residential uses. Although only moderately toxic, the EPA considers it to be a potential human carcinogen.
THMs are chemicals that can form during water disinfection involving chlorine. Exposure to large amounts of THMs can affect the central nervous system, liver, kidneys and thyroid. Some common THMs are known carcinogens.
Tritium is a naturally occurring radioactive isotope found in most water. It is generally not a health concern.
Turbidity is water cloudiness. Turbid water is typically not a health concern, but can interfere with water treatment and may be a factor leading to more significant water problems.
Uranium is a naturally occurring radioactive element found in virtually all rocks, soil, and water. Long term exposure to large amounts can lead to increased cancer risk and liver damage.
Vanadium is a naturally occurring transition metal that is not generally considered a water treatment problem.
Vinyl chloride is a colorless organic gas with a sweet odor, used in product manufacturing. It is highly toxic and carcinogenic.
Volatile organic chemicals (VOCs) are chemicals that evaporate easily from water to air. They come from a variety of sources, including pesticides and as by-products of water chlorination.
Xylenes are organic compounds with a wide range of industrial uses. Long term exposure can lead to kidney, liver and nervous system damage.
Zinc is an essential nutrient, sometimes found in large quantities in tap water due to leaching from pipes. Long term exposure to large amounts can lead to copper deficiency or problems with the immune and digestive systems.
(whole house & well units)