Facts about sodium in drinking water

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Consumers of food and water have become more conscious of the amount of sodium that they ingest, especially for those individuals on sodium restricted diets. The information below is intended to assist Almonte customers determine the contribution from drinking water to their total sodium dietary intake. Recently the water supplied to the Mississippi Mills Drinking Water Supply System exceeded the mandatory reporting limit of 20 mg/L for sodium. Drinking water with sodium concentration greater than 20 mg/L is common in many other municipalities in Ontario. The amount of sodium in Almonte’s drinking water does not pose a health risk to our customers and in fact the province has not established a health related standard for sodium in drinking water.

What is sodium?

Sodium is a naturally occurring mineral in food and water, and is a necessary element of human health. . Typically the consumption of sodium from food is much higher than from drinking water.

How does sodium get into the drinking water?

Sodium in raw water sources can vary dramatically depending on the source – lakes, rivers or wells. The naturally occurring sodium levels in the Town’s groundwater aquifers have historically ranged between 39 mg/L and 57 mg/L. No sodium is otherwise added as part of the Town’s water treatment process.

How much sodium is acceptable in drinking water?

The Guidelines for Canadian Drinking Water Quality and Ontario Drinking Water Quality Standards (ODWS) set an aesthetic objective (non-health related) for sodium in drinking water at 200 mg/L, at which point it can be detected by a salty taste by the average person. The province has not specified a health related maximum acceptable concentration in drinking water in the ODWS.

Under the Safe Drinking Water Act, the Ontario Drinking Water Systems Regulation (170/03) requires that a report be made to the local Medical Officer(s) of Health if a sodium result exceeds 20 mg/L in a sample of drinking water. When a sodium sample result in drinking water exceeds 20 mg/L, the Medical Officer of Health informs physicians and other health professionals to help people following sodium restricted diets determine their sodium intake.

How often is sodium testing conducted on the Mississippi Mills Drinking Water Supply?

Under the Ontario Drinking Systems Regulation (O. Reg. 170/03), drinking water systems are required to test water supplies for sodium once every 5 years. All samples are sent to an external accredited laboratory for analysis. The Town of Mississippi Mills carries out this mandatory testing and includes the data within the drinking water reports published and posted online annually.

How much sodium is in drinking water supplied to Almonte?

In 2013, the sodium level in the Almonte water supply was tested at wells 3, 5, 7 and 8 and results ranged from 39 mg/L to 57 mg/L. Additional testing completed in 2015, on well 6 similarly yielded results ranging from 40 mg/L to 42 mg/L. Sodium levels above 20 mg/L are not uncommon in drinking-water; in fact, several municipalities in Ontario have sodium levels that regularly exceed 50 mg/L.

How will sodium levels greater than 20 mg/L affect my health?

The human body requires sodium to maintain blood pressure, control fluid levels and for normal nerve and muscle function. Health Canada puts the adequate intake of sodium for healthy people (14-50 years old) at 1,500 mg per day; however, individuals on sodium restricted diets should consider the amount of sodium in the water when calculating their sodium intake. When sodium levels in drinking water are at 20 mg/L, drinking 2 litres per day would contribute 40 mg of sodium to a person’s diet. For healthy adults, this level of sodium in drinking water does not pose a health risk.

Other sources of sodium

Food products, not water, are the major dietary sources of sodium. Sodium is also found in drugs such as antacids, laxatives, aspirin and cough medicines, as well as table salt. One teaspoon of table salt contains 2,300 mg of sodium. Municipal tap water at 20 milligrams per litre (mg/L) or 5 mg/250 ml (one cup) has a relatively low sodium content when compared with other beverages. Public health professionals encourage using safe water to quench thirst. Here are some sodium content comparisons with other common beverages according to Health Canada’s Canadian Nutrient File:

Ginger-ale – 18 mg/250 mL

Fruit flavoured sports drinks – 101 mg/250 mL

Skim Milk – 109 mg/250 mL 436 mg/L

Chocolate Milk (1%) – 644 mg/L

Low sodium tomato juice – 179 mg/mL

Canned carrot juice – 72 mg/250 mL

Reduced sodium, canned chicken broth – 586 mg/250 mL

What should I do about sodium in drinking water?

Most people do not need to take any action. If you are on a sodium-restricted diet or are concerned about the effects of sodium on your personal health concerns consult your physician about the concentrations of sodium in your drinking water together with the sodium from your food, beverages and medications.

References and Additional Information

For more information on sodium go to the Leeds, Grenville and Lanark District Health Unit website at http://www.healthunit.org/nutrition/hottopics/salt_sugar_myths.html

Ontario Ministry of Health and Long Term Care

http://www.mhp.gov.on.ca/en/healthy-ontario/healthy-eating/salt.asp

All Ontario residents can speak with a Registered Dietitian at no cost by calling Eat Right Ontario toll free 1-877-510-5102

To calculate the amount of sodium in common foods and beverages go to Health Canada – Canadian Nutrient File http://www.hc-sc.gc.ca/fn-an/nutrition/fiche-nutri-data/cnf_aboutus-aproposdenous_fcen-eng.php

Or, look up common foods in

Health Canada – Nutrient Value of Some Common Foods http://www.hc-sc.gc.ca/fn-an/alt_formats/pdf/nutrition/fiche-nutri-data/nvscf-vnqau-eng.pdf

If you should have any further questions or require any further information, please contact the Town of Mississippi Mills Roads and Public Works Department at (613) 256-2064 Ext. 258.