Chloride ions, or ionized chloride atoms, are derived mostly from salt deposits that leech into water. Some common chlorides include sodium chloride (NaCl) and magnesium chloride (MgCl2). Fresh water has almost no chlorine ions whatsoever, whilst saltwater from the ocean has the highest quantity of chloride ions. Many wells and water reservoirs can also build up chlorine ions from underground salt deposits, or deep aquifers that originate from ancient marine basins. Industrial processes combined with poor maintenance of filters and controls can also lead to a high Chloride concentration.
Why Test for Chloride?
Chlorides can corrode metals and pipes. It can affect the taste of food products, cause nausea and vomiting. Therefore, water that is used in industry or processed for any use has a maximum Chloride level. Chlorides can also contaminate fresh water streams and lakes, leading to death of aquatic life.
Measurement of Chlorides can be done using a colorimetric system or a photometric system. If you have a Lovibond® Comparator or a Photometer capable of measuring many parameters, you can obtain additional reagents for measuring Chloride levels.
Criteria in South Africa:
Criteria for protection of aquatic life requires levels of less than 600 ml / litre for chronic long-term exposure and 1200 mg / litre for short-term exposure.
< 300 mg / litre
* SANS 241-1: 2011 Drinking Water Standards