| Type |
Contaminant |
Possible Health Effects |
Sources of Contaminant in
Drinking Water |
| Microbiological |
Cryptosporidium |
Cryptosporidosis |
Human and animal fecal wastes |
| |
Giardia |
Gastroenteric disease |
Human and animal fecal wastes |
| |
Coliform bacteria |
Gastroenteric disease, including dysentery, cholera |
Human and animal fecal wastes |
| Inorganic chemicals |
Asbestos |
Cancer |
Natural deposits; asbestos cement in
water systems |
| |
Barium |
Circulatory system effects |
Natural deposits; pigments, epoxy sealant, spent coal |
| |
Cadmium |
Kidney effects |
Galvanized pipe corrosion; natural
deposits; batteries, paints |
| |
Fluoride |
Skeletal and dental damage (tooth discoloration) |
Natural deposits; fertilizer, aluminum industry; drinking
water additive |
| |
Lead |
Kidney and nervous system damage |
Natural/industrial deposits; plumbing,
solder, brass alloy faucets |
| |
Mercury (inorganic) |
Kidney, nervous system disorders |
Crop runoff; natural deposits; batteries, electrical
switches |
| |
Nitrate |
Methemoglobulinemia (Blue Baby Syndrome) |
Animal waste, fertilizer, natural
deposits, septic tanks, sewage |
| |
Selenium |
Liver damage |
Natural deposits; mining, smelting, coal/oil combustion |
| Organic chemicals |
Alachlor |
Cancer |
Runoff from herbicide on corn, soybeans,
and other crops |
| |
Atrazine |
Mammary gland tumors |
Runoff from use as herbicide on corn and non-cropland |
| |
Benzene |
Cancer |
Gasoline, drugs, pesticides, paint,
plastic industries |
| |
Carbon Tetrachloride |
Cancer |
Solvents and their degradation products |
| |
Dioxin |
Cancer |
Chemical production by-product; impurity
in herbicides |
| |
Endrin |
Liver, kidney, heart damage |
Pesticide on insects, rodents, birds; restricted since
1980 |
| |
Lindane |
Liver, kidney, nervous, immune,
circulatory system effects |
Insecticide on cattle, lumber, gardens;
restricted since 1983 |
| |
Methoxychlor |
Growth, liver, kidney, nerve effects |
Insecticide for fruits, vegetables, alfalfa, livestock,
pets |
| |
PCBs |
Cancer |
Coolant oils from electrical
transformers; plasticizers |
| |
Styrene |
Liver and nervous system damage |
Plastics, rubber, resin, drug industries; leachate from
city landfills |
| |
Toluene |
Liver, kidney, nervous and circulatory
system effects |
Gasoline additive; manufacturing and
solvent operations |
| |
Total Trihalomethanes |
Cancer |
Drinking water chlorination by-products |
| |
Vinyl Chloride |
Cancer |
May leach from PVC pipe; formed by
solvent break down |
| Source: EPA, National Primary and
Secondary Drinking Water Standards Learn how to get clean drinking
water today! |
