Antimony

Antimony is a bluish-white metallic element which is rare in nature. Antimony is used in the fire retardant, plastic, semiconductor, rubber, textile, paint, and glass industries. Potential sources of contamination in drinking water include petroleum refinery discharge, fire retardants, ceramics, electronics, and solder.
The US Environmental Protection Agency (USEPA) has set a drinking water standard of 0.006 mg/L for antimony in public drinking water supplies. These regulations do not apply to private water supplies but the health implications are the same for private well owners.
100 mg of antimony has been shown to be acutely lethal. It would take over 400 gallons of antimony contaminated water at 10 times the USEPA standard to kill someone immediately. The more likely type of health effect from antimony comes from low dosages over a long period of time or “chronic” effects. Health effects from antimony include increased risk of cancer, increase in blood cholesterol, and a decrease in blood sugar.
Treatment of water for antimony can be accomplished with reverse osmosis.