Chloride

GENERAL INFORMATION
As ground water moves through bedrock or sand and gravel geologic deposits in the subsurface, it will dissolve different minerals and constituents including chloride. Chloride occurs naturally in ground water as a component of deposited salts in geologic formations. The levels of chloride may vary in water wells depending on the type of rock the ground water moves through and how long the ground water is in contact with the rock and has the ability to dissolve minerals. Deeper wells may have higher levels of chloride because the ground water has dissolved many of the naturally occurring minerals over time. Chloride levels in water wells that are higher than normal background levels may indicate that chloride has migrated into the ground water from other sources such as:

• de-icing salt and salt storage areas,
• brines produced during oil and gas well drilling,
• sewage effluent, softener discharge,
• landfills,
• irrigation drainage,
• animal manure and fertilizers, and
• industrial waste.

The presence of chloride does not always mean the water is saline. Water is considered saline when the total dissolved solids in the water reaches levels of 1000 mg/L and greater.

HEALTH EFFECTS
There are no known health effects associated from chlorides. Sodium, which is often associated with chloride, may be of concern with people suffering from heart or kidney disease.

AESTHETIC EFFECTS
The water has a salty taste at concentrations above the SMCL of 250 mg/l.