Drinking Water

While fluoride levels up to 2.4 mg/L are safe to drink, fluoride levels above 1.5 mg/L may cause dental fluorosis (discolouration of the teeth) in children seven years of age and under. Southwestern Public Health recommends households with young children in areas with naturally occurring high levels of fluoride to cut back on other sources of fluoride to prevent fluorosis, like choosing non-fluoride toothpaste and using bottled water for baby formula (after it has been boiled and cooled.)

The following recommendations are intended to minimize the effects of fluoride in the water system if levels are above 1.5mg/L:

Water treatment. Use a home treatment system to remove or reduce the fluoride content if there are young children in the home. Only reverse osmosis and distillation processes remove fluoride. Charcoal filters do not remove fluoride.

Use other sources of water. If it is not possible to use a home treatment system, consider using water from another source with a lower fluoride level (e.g., non-fluoridated, bottled water) for drinking, cooking, mixing juices or making baby formula, especially when there are young children in the home. Bottled water, like tap water, must be sterilized when used to make baby formula.

Non-fluoride toothpaste. Consider using non-fluoride toothpaste for children up to and including 6 years of age, or no toothpaste for children up to 3 years of age, especially for children who may swallow toothpaste. Parents should only use a small amount of toothpaste (pea-size or a smear) regardless of fluoride levels in the water and should always supervise the amount of toothpaste being used.

Don’t use fluoride supplements. Fluoride supplements should not be used in areas with naturally occurring fluoride.

Consult with your dentist. A fluoride treatment at the dentist is not likely to contribute to fluorosis; however, parents should discuss the use of any dental products with their dentist.

How are fluoride levels monitored?

Some private water wells may also contain naturally occurring fluoride levels above the recommended level of 1.5 mg/L. Public Health recommends regular testing of well water: three times a year for bacteria, and once a year for fluoride and nitrates in communities with known elevated fluoride levels. 

Lead occurs naturally in the earth’s crust in small amounts. It can be found everywhere in our environment, not only because it occurs naturally, but also because it’s used extensively in modern industry (mining, manufacturing and burning of fossil fuels).

Humans are exposed to lead in both outdoor and indoor environments. It is found in the air, soil, dust, drinking water, food and various consumer products.

Concentrations of lead in the environment increased significantly following the industrial revolution. Over the past 25 years, Health Canada, Environment Canada, and other Canadian regulatory agencies have substantially reduced Canadian’s exposure to lead by legislating and enforcing maximum lead concentrations in gasoline and house paints. Also, the use of lead-soldered food cans has been virtually eliminated through an agreement negotiated with Canadian canneries.

Lead may enter the body through the mouth (ingestion), the lungs (inhalation) or the skin (dermal route). The growing fetus may also be exposed to lead from the mother via the placenta. In Canada, the main exposure routes are ingestion or inhalation. The most common route of entry is ingestion, except in industrial environments, where inhalation of lead fumes may play a larger role.

Absorption of lead through the skin is rare. Children are at greater risk of ingesting lead due to their frequent hand-to-mouth activity and tendency to mouth or chew objects they come into contact with (especially non-food products such as paint chips, furniture or toys).

Regardless of the route of entry, lead is absorbed directly through the blood into tissue.

Lead has no known biological function in the body. Once absorbed, it circulates in the bloodstream and either accumulates in tissues or is excreted as waste. Some of it is absorbed into soft tissue such as the liver, kidneys, pancreas and lungs. A very high proportion of absorbed lead is transferred to bone (hard tissue), where it accumulates over time and remains for long periods. The half-life (time for the body to excrete half the accumulated lead) is about 25 years. High lead concentrations can stay in the body for many years after exposure to lead has stopped.

Some of the more prominent symptoms of lead poisoning include headaches, irritability, abdominal pain, vomiting, anemia (general weakness, paleness), weight loss, poor attention span, noticeable learning difficulty, slowed speech development and hyperactivity.

However, at very low exposure levels, lead may not produce specific symptoms, but still can produce subtle adverse effects on children’s development.

Lead levels in tap water will increase with the length of time water is left standing in pipes. At home, you can let tap water run before drinking it if it has been standing in the pipes for a few hours. Turn on the taps until the water runs cold first thing in the morning or at any other time when the water has been left standing in your home’s plumbing system for a long time.

However, in many cases, normal domestic activities in the morning, such as showering and flushing toilets, should minimize the need to flush taps. To conserve water and avoid the extensive flushing of taps, you can also keep some drinking water in the refrigerator.

You can also minimize lead levels by using only cold water for drinking, cooking and making baby formula. Hot or warm water tends to acquire more lead, especially in those areas that have soft water. Lead contamination is more evident in areas with soft drinking water because this water tends to be acidic (low pH). Such conditions favour the leaching of lead from plumbing.

• Run the water from the drinking water tap if it has been sitting in the pipes for 6 hours or more. Water should be flushed for at least five (5) minutes.
• Use cold, flushed water for drinking and preparing food. Water from the hot water tap should not be consumed as it may contain more lead.
• Younger children are still developing and are therefore more sensitive to the neurologic and blood effects of lead.  As well, children less than 6 years of age absorb lead more easily than adults. Particular recommendations are made for formula-fed infants because the water used to make the formula can contribute 40 – 60% of an infant’s lead intake, whereas drinking water in older children and adults only contributes approximately 10% of total lead intake.
• Pregnant women can pass lead in their blood to their fetus during pregnancy.  Therefore, particular recommendations are made to keep lead levels in pregnant women as low as possible.
• If there are children under the age of 6 or pregnant women living in the house, follow the recommendations listed below.

Households with children under 6 or pregnant women:

• Children under the age of 6 and pregnant women should drink bottled water or use an approved filter attached to the tap or an approved water-pitcher filtration system. Make sure any filtration product purchased is certified as meeting the National Sanitation Foundation (NSF) International standard for reducing lead. This recommendation is especially important for infants whose formula is prepared by adding tap water to liquid concentrate or powder.
• When using filtration devices it is very important to follow the manufacturer’s instructions carefully.
• When using a filter device be sure that:
  • The water is free of bacteria.
  • The water is flushed for at least 30 seconds if the filter is on the tap.
  • The filter is changed at the times recommended by the manufacturer.
• The label on bottled water should be checked to ensure it is lead-free. Lead content is listed on the “Analysis Label” and is also referred to as “Pb”. The water is lead-free if the value for lead is zero. It is important to note that not all bottled water is lead-free.
• If your water has been shown to have lead levels below the recommended 10 micrograms/L, continue to flush your water for at least 5 minutes before use, as recommended above. Filters and bottled water are no longer needed.

No. Over the years, the major sources of lead exposure for children have decreased significantly because of the elimination of lead in gasoline, paint and solder in tin cans.  Other jurisdictions have similar lead issues in their drinking water systems.  In some areas where lead toxicity is reportable to public health, significantly elevated blood lead levels have not been reported.  Lead toxicity is not reportable to public health in Ontario; however, local testing for lead levels in blood has not revealed any concerns related to lead in drinking water.  Parents are advised to discuss specific health concerns with their physicians.

For more information on lead in drinking water, contact our Environmental Health team at 1-800-922-0096 or visit the following websites.

• Health Canada
• Canadian Mortgage and Housing Corporation
• Ministry of Environment Licensed Labs that test for lead

If you have questions about lead service lines, please contact your municipal office.

Source: Health Canada “Lead Information Package Some Commonly Asked Questions About Lead and Human Health”

Sodium is a nutrient found in table salt and many other foods. Your body needs some sodium to function, but too much may lead to high blood pressure (a major risk factor for stroke, heart disease and kidney disease). Most Canadians take in more than twice the amount of sodium they need in a day.

In Oxford County, natural sodium levels in drinking water are high enough that people on a sodium-restricted diet should be aware of how much sodium they are taking in through their water.

For a healthy adult, the level of sodium in the water supply does not pose a risk to health. However, if you or members of your family have kidney disease, heart disease, high blood pressure or liver disease, and need to restrict your salt intake because of these illnesses, please ask your physician or health care professional how sodium in the water may affect your health.

Sodium is a mineral that occurs naturally in raw water sources. At the Elgin Area Primary Water Supply System (EAPWSS), naturally occurring sodium in Lake Erie can contribute as much as three quarters of the sodium in the drinking water. The lake water’s naturally occurring sodium levels range between 8 mg/L and 14 mg/L, with the remainder of the sodium in the treated drinking water coming from the water treatment process. To find out what the sodium levels are in within Oxford County, visit the Drinking Water Annual Reports.

In addition, people using a water softening system in their home may have higher levels of sodium in their drinking water as most softeners use a calcium-sodium exchange system. This may add significant amounts of sodium to drinking water in the home. There are some treatment systems that may reduce the amount of sodium from softened water, including reverse osmosis, ion exchange or distillation units. Alternatively, a separate water line which bypasses the water softener can be used for drinking and cooking.

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

The Safe Drinking Water Act, the Ontario Drinking Water Systems Regulation (Ontario Regulation 170/03), requires that a report be made to the local Medical Officer of Health if a sodium result is higher than 20 mg/L in a sample of drinking water so that local physicians and other health professionals can be advised of this to help those on sodium restricted diets control their sodium intake.

Healthy adults (14-50 years old) should consume between 1500 and 2300 mg of sodium each day; however, for individuals on sodium restricted diets, the amount of sodium in the water may be significant. 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; however, for people on a very strict sodium restricted diet of 500 mg per day, this would contribute about 8% of their daily sodium allowance.

When sodium levels are higher than 20 mg/L, the Medical Officer of Health is required to inform the public, through health professionals, in order to help people on sodium-restricted diets control their sodium intake.

The bacteriological safety of municipal drinking water is not affected by sodium levels, meaning that the water is safe to drink.

Oxford County tests for sodium in drinking water every five years. To find out what the sodium levels are in within Oxford County, visit the Drinking Water Annual Reports.

Oxford County municipal water containing sodium levels under 20 mg/L is considered safe for drinking.

For information on drinking water and sodium levels in Elgin County, visit the Elgin Area Primary Water Supply System (EAPWSS) website. 

If you have questions about the safety of your drinking water, please consult your health care professional, or call Southwestern Public Health at 1-800-922-0096.

Nitrate is a chemical compound that occurs naturally throughout the environment in groundwater, plants including fruits and vegetables or may be present due to human activities.  Nitrate is formed when nitrogen combines with oxygen or ozone. Nitrogen is essential for all living things, but high levels in drinking water can be harmful to health, especially for infants.

How much nitrate is allowed in drinking water?

The Ontario Drinking Water Quality Standard for nitrate is 10 milligrams per litre (mg/L) measured as nitrogen. This is the maximum acceptable concentration (MAC) for nitrate drinking water.

How does nitrate get into drinking water?

Nitrate can occur naturally in surface and groundwater at low levels that do not cause health problems. However, high levels of nitrate in surface and groundwater can result from agricultural runoff, improper well construction, natural decay of organic matter in groundwater and leaking septic systems.

Water wells that are shallow, dug, bored or prone to flooding may be more vulnerable to such contamination.

What are the health effects?

Potential health effects of nitrates in drinking water depend on how much nitrate a person is exposed to, how long they were exposed, their age, and pre-existing health conditions. The level of nitrates most people are exposed to would not cause adverse health effects.

Exposure to an elevated level of nitrate in drinking water is primarily a health concern for bottle-fed infants less than six months of age who have not yet developed the ability to properly digest nitrate. This can lead to a rare but very serious condition called methemoglobinemia or blue-baby syndrome. Methemoglobinemia impacts the delivery of oxygen to tissues in the body, resulting in a bluish skin colour, particularly around the mouth and eyes due to a lack of oxygen.

Other susceptible individuals include pregnant women and people with certain blood disorders.

If the level of nitrate in your water is above 10mg/L, you should use a different water supply to prepare baby formula and food or use ready-to-use formula. Breastmilk is not affected by nitrates and is considered safe.

How do I know if I have nitrate in my drinking water?

Nitrate is a colourless, tasteless, and odourless compound. The only way to know whether there is nitrate in your drinking water is to have it tested by a licensed laboratory. Municipal drinking water systems are required to be tested regularly.  If you draw your drinking water from a well, the health unit recommends testing your well water for nitrate at least once a year, especially if anyone consuming the water is pregnant or under the age of one. Visit the Ministry of the Environment, Conservation and Parks website for a complete list of accredited laboratories.

It is also recommended that you test your well water for bacteria at least three times a year. Bacterial contamination can be an indicator that surface water is entering your well which may also contain nitrate. Free well water testing is available to private residences year-round. Water samples are submitted to the London Public Health Laboratory where they are tested for total coliform and E. coli bacteria.

Reducing Your Exposure

Here are a few ways you can help keep your water safe:

• Improve agricultural practices such as fertilizer storage and manure application.
• Have your septic system inspected by a licensed installer every 3-5 years.
• Avoid activities such as mixing or storing chemicals around water wells.
• Regularly inspect your well for cracks and evidence of flooding.

If you are further concerned about nitrate in your drinking water, it is recommended that you contact a water treatment professional about installing a water treatment device to reduce the amount of nitrate in your drinking water. Boiling water will not remove nitrate and will only increase the concentration of nitrate in the water.