Lead Information Package - Some Commonly Asked Questions About Lead and Human Health

Sources of Exposure

• What are the sources of lead exposure?
• Should I be concerned about lead concentrations in the air?
• Should I be concerned about lead in soils?
• Is there lead in gasoline?
• Should I be concerned about lead concentrations in drinking water supplies?
• What are the potential sources of lead that could get into my home's water supply?
• How can I reduce the lead levels in tap water?
• How does the level of lead in water from drinking water fountains compare to the level of lead in tap water?
• Does the age of my home affect the level of lead in drinking water?
• What can a municipality do to reduce lead levels in water?
• How should I dispose of a product that contains lead?

What are the sources of lead exposure?

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, most dramatically since the 1920s, following the introduction of lead additives in automobile gasoline. However, over the past 25 years, Health Canada, Environment Canada, and other Canadian regulatory agencies have substantially reduced Canadian's exposure to lead by, for example, 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.

Outdoor Environments

Air

Should I be concerned about lead concentrations in the air?

Lead concentrations in the air have declined significantly since the introduction of unleaded gasoline in Canada in 1975. Currently, the level of lead in the air of most Canadian cities is below the detectable level so, generally, there is no need to be concerned.

There could be some concern for people living near a point source, such as a smelter or refinery, where lead is released into the air through industrial emissions. However, the levels of lead from smelter emissions are regulated under the Canadian Environmental Protection Act (CEPA).

Dust and Soil

Should I be concerned about lead in soils?

Lead can be found everywhere in our environment. Most of the lead in soils comes from particles falling out of the air and from rocks that contain lead. Lead-contaminated dust and soil can cling to skin, hair, shoes, clothing and vehicles and can be carried indoors.

Dust and soil can be a source of lead exposure for small children because they are close to the ground and because of their hand to mouth activity. It is, however, very unlikely that a child could inhale or consume an amount significant enough to result in elevated blood levels.

Leaded Gasoline

Is there lead in gasoline?

Concentrations of lead in the environment increased following the introduction of lead additives in automobile gasoline. Then, between 1973 and 1985, airborne lead concentrations fell considerably due to the increased use of unleaded gasoline. Since 1990, the use of leaded gasoline in motor vehicles has been prohibited in Canada, under the Canadian Environmental Protection Act (CEPA). Although leaded gasoline is no longer used in Canada as an on-road automotive fuel, lead particles from gasoline emissions are still a source of lead in our environment today. In addition, leaded gasoline is still being used in many countries, so contamination of the atmosphere continues.

Water

Should I be concerned about lead concentrations in drinking water supplies?

In Canada, the concentration of lead in drinking water supplies do not represent a hazard to Canadians as concentrations are normally below the maximum acceptable concentration of 0.010 mg/L.

What are the potential sources of lead that could get into my home's water supply?

In Canada, the concentration of lead in drinking water is generally below the Canadian guideline of 0.010 mg/L as it leaves the treatment plant. However, lead may enter potable water at several points between water treatment plants and people's homes. The use of lead in valve parts or gaskets in treatment plants and the use of lead in older distribution mains and service lines are all potential sources. In dwellings, pipe jointing compounds, soldered joints and brass fixtures are also possible sources of lead.

If you are concerned about potential elevated lead levels in your home's drinking water, you can contact your municipality's public health inspector or environmental health officer.

How can I reduce the lead levels in tap water?

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.

How does the level of lead in water from drinking water fountains compare to the level of lead in tap water?

Water from drinking fountains may have higher levels of lead than water from nearby taps because they contain more piping, soldered joints and fittings from which lead may leach. In addition, the water usually sits in the fountain for longer periods of time prior to use.

Does the age of my home affect the level of lead in drinking water?

Lead levels may be higher in old (pre-1950) or very new homes. In old homes, the problem often arises because of leaded distribution lines and service connections. In newer homes, excessive leaching from leaded solder and brass fixtures (e.g., faucets), may occur for the first year until a protective oxide layer has formed in the pipes.

Since 1990, the Canadian National Plumbing Code has restricted the use of lead solder in new plumbing and in repairs to plumbing for drinking water supplies. Several provinces have also passed legislation limiting the amount of lead in solder used for drinking water supply lines..

If you are concerned about potential elevated lead levels in your home's drinking water, you can contact your municipality's public health inspector or environmental health officer.

What can a municipality do to reduce lead levels in water?

A municipality can evaluate and potentially modify the water's alkalinity and pH levels. In addition, the municipality can use a corrosion inhibitor, which can react with the dissolved lead to form a protective coating on the inside of pipes to reduce the amount of lead leaching into drinking water.

Lead in Waste

How should I dispose of a product that contains lead?

Such products must be disposed of carefully to avoid contaminating the environment. When products such as waste oil, colored newsprint, battery casings or lead-painted wood are burned, lead fumes or particles are released into the air and may be inhaled. When products such as batteries and paint scrapings are thrown out and make their way into landfills, or when lead shot, sinkers and jiggers are left in the environment, they create a lead reservoir. This reservoir slowly leaches into soils, sediments, and water.

In the environment, these products break down to form lead oxides, carbonates and other inorganic lead compounds. Lead in contaminated sediments can be stored in the tissues of a variety of species. Since humans are at the top of the food chain, we have a high probability of ingesting a portion of this lead as it makes its way through the food chain. In addition, surface water that contains lead can migrate into the soil and into groundwater reserves and enter water courses that may be used as sources of drinking water.

In many areas of Canada, special arrangements exist for the disposal of hazardous household wastes. Leaded products, such as paint scrapings and batteries, should not be discarded with the garbage. To find out how to dispose of old products, contact either your local municipality, or the local office of your provincial or territorial Ministry of the Environment.