Sodium in Drinking Water Information:

Properties:

Sodium is an element that is widely abundant in soil, rock formations, and water sources.1 It can be present as a cation in a variety of compounds and salts. For example, sodium chloride—more commonly known as table salt—is one common sodium-containing compound that humans encounter daily. Elemental sodium metal is highly reactive and cannot be found in its pure form in nature.

Sources:

Both natural and anthropogenic sodium sources can contribute to elevated concentrations in drinking water supplies. Sodium-containing compounds are used in the production of various chemicals and materials, in water treatment processes such as softening or pH adjustment, and in paper, soap, glass, pharmaceutical, chemical and food industries.2 Sodium is also present in human waste; contamination of raw water by sewage can increase sodium concentrations and pose other, more serious risks.

Regulations:

The concentration of sodium in drinking water may not exceed 200 milligrams per litre (mg/L).

Health/Environmental Concerns:

Sodium is an essential dietary nutrient for humans, but high concentrations can be detrimental to overall health. Extremely high sodium intake can cause nausea, vomiting, muscle contraction, and oedema.2 For individuals with hypertension and congestive heart failure, high sodium intake is not recommended due to its potential to exacerbate existing symptoms and cause additional negative health impacts.1  

Action:

High sodium levels can indicate that drinking water has been contaminated by sewage and may contain other harmful chemicals and bacteria. In these cases, immediate action is necessary to protect consumer health. In other cases where sodium levels exceed regulatory limits, the most effective strategies for mitigation are those that prevent contamination from reaching the water supply in the first place.1 Other methods such as desalination and reverse osmosis are effective but can be extremely costly. If you suspect that your drinking water supply is contaminated, contact your Water Service Authority. If drinking water makes you feel ill, contact a doctor right away.

1 Guide to the Parameters in the European Communities. What’s in your water?;  S. I. No. 278 of 2007; National Federation of Group Water Schemes: Ireland.

2 Guidelines for Drinking Water Quality. Sodium in Drinking Water; Vol. 2; World Health Organisation: Switzerland, 1996