Antimony, Sb
MCL	0.005 mg/l
Risks or effects	Decreases longevity and growth, carcinogen, irritation to eyes and skin tissue
Sources	Fire retardants, ceramics, electronics, fireworks, solder
Treatment	Coagulation, Reverse Osmosis, filtration, Distillation

Arsenic, As
MCL	0.05 mg/l
Risks or effects	Weight loss; Depression; Lack of energy; Skin and nervous system toxicity; Human Carcinogen
Sources	Previously used in pesticides (orchards) Improper waste disposal or product storage of glass or electronics, Mining Rocks
Treatment	Activated Alumina Filtration, Reverse Osmosis, Distillation, Chemical Precipitation, Ion exchange, lime softening

Asbestos
MCL	7 million fibers per liter applies to fiber lengths of 10 microns or greater
Risks or effects	Benign tumors, probable cause of cancer
Sources	Cement pipes, Fire retardant, roofing materials
Treatment	Coagulation

Barium, Ba
MCL	2 mg/l
Risks or effects	Toxic effects on the heart, blood vessels and nerves; accumulates in the liver, lungs and spleen; Nervous system disorders; High blood pressure and heart disease; Circulation impairment; Lethal doses is 550 mg
Sources	Paints, diesel fuel combustion Paints, diesel fuel combustion Diesel fuel combustion, jet fuel, mining Rocks and soils
Treatment	Ion Exchange, Lime Softening, Reverse Osmosis, Distillation

Beryllium, Be
MCL	0.004 mg/l
Risks or effects	Bone and lung damage, carcinogen
Sources	Electrical, aerospace (rocket fuels) and nuclear industries Geological
Treatment	Activated carbon, Coagulation/filtration, Ion Exchange, Lime Softening, Reverse osmosis, Distillation

Cadmium, Cd
MCL	0.005 mg/l
Risks or effects	Kidney damage related to high blood pressure, Itai-itai disease in Japan, Mutagenic
Sources	Fertilizers, Sewage waste Discarded batteries, Paints, Landfills, Fertilizers, Galvanized pipes Waste water, Petroleum and coal mining, electroplating, Hazardous Waste Landfills, lead and copper smelting Geological
Treatment	Chemical precipitation, Coagulation/filtration, Ion Exchange, Lime Softening, Reverse Osmosis, Distillation, Corrosion Control

Chromium, Cr
MCL	0.1 mg/l
Risks or effects	Skin irritation, skin and nasal ulcers, lung tumors, gastrointestinal effects, damage to the nervous system and circulatory system, accumulates in the spleen, bones, kidney and liver
Sources	Septic systems Industrial discharge, mining sites Geological
Treatment	Coagulation/Filtration, Ion Exchange, Lime Softening, Reverse Osmosis, Distillation

Copper, Cu
Activation Level	1.3 mg/l
Risks or effects	Anemia, digestive disturbances, liver and kidney damage, gastrointestinal irritations, bitter or metallic taste; Blue-green stains on plumbing fixtures
Sources	Leaching from copper water pipes and tubing, algae treatment Industrial and mining waste, wood preservatives Natural deposits
Treatment	Ion Exchange, Reverse Osmosis, Distillation

Cyanide
MCL	0.2 mg/l
Risks or effects	Thyroid, nervous system damage
Sources	Fertilizer Electronics, steel, plastics mining
Treatment	Ion Exchange, Reverse Osmosis, Chlorination

Fluoride, F
MCL	4.0 mg/l
Risks or effects	Brownish discoloration of teeth, bone damage
Sources	Industrial waste Geological
Treatment	Activated Alumina, Distillation, Reverse Osmosis, Ion Exchange

Lead, Pb
Activation Level	0.015 mg/l
Risks or effects	Reduces mental capacity (mental retardation), interference with kidney and neurological functions, hearing loss, blood disorders, hypertension, death at high levels
Sources	Paint, diesel fuel combustion Pipes and solder, discarded batteries, paint, leaded gasoline Natural deposits
Treatment	Ion Exchange, Actived Carbon , Reverse Osmosis, Distillation, Coagulation with Filtration, Corrosion control

Mercury, Hg
MCL	0.002 mg/l
Risks or effects	Loss of vision and hearing, intellectual deterioration, kidney and nervous system disorders, death at high levels
Sources	Fungicides Batteries, fungicides Mining, electrical equipment, plant, paper and vinyl chloride Natural deposits
Treatment	Actived Carbon, Lime Softening, Coagulation, Reverse Osmosis, Distillation

Nickel, Ni
MCL	0.1 mg/l
Risks or effects	Heart and liver damage, Carcinogen, Dermatitis
Sources	Discarded batteries Metal alloys, electroplating chemical production Geological
Treatment	Ion Exchange, Lime Softening, Reverse Osmosis, Distillation

Nitrate, NO3-
MCL	10 mg/l
Risks or effects	Methemoglobinemia or blue baby disease in infants
Sources	Livestock facilities, septic systems, manure lagoons, fertilizers Household waste water, fertilizers Fertilizers Natural Deposits
Treatment	Ion Exchange, Distillation, Reverse Osmosis

Nitrite, NO2-
MCL	1 mg/l
Risks or effects	Methemoglobinemia or blue baby disease in infants, rapidly converted to nitrate
Sources	Livestock facilities, septic systems, manure lagoons, fertilizers Household waste water, fertilizers Fertilizers Natural Deposits
Treatment	Ion Exchange, Distillation, Reverse Osmosis

Selenium, Se
MCL	0.05 mg/l
Risks or effects	Growth inhibition, skin discoloration, digestive problems, liver damage, psychological disorders, neurological effects
Sources	Fungicides Fungicides Mining, coal and oil burning, manufacture of paints, smelting Geological
Treatment	Distillation, Activated Alumina, Chemical Precipitation, Ion Exchange, Lime Softening, Coagulation/Filtration, Reverse Osmosis

Thallium, Tl
MCL	0.002 mg/l
Risks or effects	Skin irritation
Sources	Manufacture of electronics, pharmacauticals, glass and alloys Geologic
Treatment	Ion Exchange, Activated Alumina, Distillation