EPA Water Contamination Chart

The following table outlines the possible causes and effects of known water contaminants as described by the U.S. Environmental Protection Agency. To return to Water 101, our guide to common water problems and frequently asked questions about water treatments, click here.

Contaminant Possible Effect(s) Source(s)
Asbestos Cancer Asbestos cement in water systems
Arsenic Cancer, skin and nervous system toxicity Pesticides, industrial waste, smelting
Barium Circulatory system effects Geological
Benzene Cancer Fuel, drugs, paint, pesticides
Cadmium Kidney effects Epoxy sealants, spent coal, pigments
Carbon Tetrachloride Cancer Cleaning solvents
Coliform & other bacteria Gastroenteric infection, dysentery, typhoid fever, and cholera Human and animal fecal matter
Endrin Liver, kidney and heart damage Pesticide on insects, rodents and birds
Fluoride Skeletal and dental damage Fluoridated water, fertilizer and aluminum
Giardia lambia Gastroenteric disease Human and animal fecal matter
Lead Kidney and nervous system damage Lead pipes and lead-based solder
Legionella Legionnaire's disease Natural waters, some water heaters
Lindane Liver, kidney, nervous, immune and circulatory system damage Insecticide on cattle, cotton and soybeans
Mercury Kidney and nervous system disorders Crop run-off, batteries
Methoxychlor Growth, liver, kidney and nerve effects Insecticide on fruits, livestock and pets
Nitrate Blue baby syndrome (methemoglobinemia) Fertilizer, sewage and animal waste
Radon Cancer Decay of radionuclides
Selenium Liver damage Smelting, coal/oil combustion
Total Trihalomethanes Cancer Surface water treated with chlorine
Toxaphene Cancer Insecticide on cattle, cotton and soybeans
Tetrachloroethylene Cancer Dry cleaning materials waste, solvents
Turbidity Interferes with Disinfection, filtration Erosion, soil run-off and discharges
Vinyl Chloride Cancer PVC Pipe, solvent breakdown


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