What is lead?
Lead is a naturally occurring metal found in rocks and soil. Historically, it has been used for a variety of purposes, including as an additive in paint and gasoline, a component of pottery glaze, and solder for water pipes.
What are the health effects of lead exposure?
Lead exposures in people are much lower than there were even 20 to 30 years ago. However, lead can be harmful to people of all ages.
- Children are most vulnerable to the harmful effects of lead because their growing bodies absorb lead more easily and get rid of it less efficiently than adults. Also, infants and young children are more likely to ingest lead because of their normal habit of putting things in their mouths.
- The amount of lead in your body depends on the level and duration of exposure.
- Exposures of lead levels that are high enough to cause immediate symptoms are unusual. More commonly, people are exposed to low levels of lead over time.
- Lead is eliminated from your body mostly in urine, but if the exposure is high enough, your blood lead level will rise and some lead can build up in your bones.
- Low to moderate levels of lead in the blood usually cause no symptoms.
- Higher blood lead levels can affect reproduction, such as sperm counts.
- Low blood lead levels may have subtle effects, such as decreased IQ in children, and high blood pressure, lower hemoglobin and decreased kidney function in adults.
- High blood lead levels typically cause abdominal pain, constipation or diarrhea, and anemia. Symptoms may also include irritability, fatigue and weakness. In severe cases, brain swelling can lead to confusion, drowsiness, vomiting and even coma and death.
Sources of Lead Exposure
The diet is the largest contributor to population lead exposure. Lead may enter food from the soil, water or air and may also contaminate food during transport and processing.
Lead can also be transferred to your food during cooking, serving or storage if you:
- cook with water contaminated with lead
- prepare or serve food using utensils, dishes and containers that leach lead
- store food in containers that leach lead such as lead-glazed glass
- eat wild game killed with lead ammunition.
Important food category contributors include bread and rolls, tea, tap water, potatoes and potato products, fermented milk products, and beer and beer-like beverages.
- Lead can be present in maple syrup. Lead can leach into the sap if lead-containing equipment is used in the manufacturing process.
- Lead has been found in some imported candies, which may become contaminated by specific ingredients, such as chili powder or tamarind, during manufacturing or storage processes, or from leaching of lead-containing ink on wrappers.
- Some traditional and herbal medicines, such as Ayurvedic medicines, have been found to contain harmful levels of lead and other heavy metals.
In most of Canada, the amount of lead in natural water supplies is very low. But lead can enter the water supply in your home from:
- old lead service connections or pipes
- lead solder in the plumbing.
Homes built before 1950 often have lead pipes. Also, lead solder was used for plumbing until 1990. Water in a plumbing system is more likely to contain lead if it:
- sits in pipes for a long time
- is very soft or acidic.
Many towns and cities have programs to replace lead service lines. To find out if your home has a lead service line, contact your municipality.
Dust and Soil
One of the main sources of lead exposure for infants and children is dust and soil. Children can be exposed to lead in soil or household dust through normal hand-to-mouth activity. Lead levels in soil tend to be higher:
- in cities
- near roadways
- around industrial sources that use or emit lead
- near weapon firing ranges
- next to buildings where crumbling leaded paint has fallen into the soil.
Contaminated soil can be tracked into your home after outdoor activities.
Lead can also enter household dust from sources already in your home, especially in older homes that contain lead-based paints. Exposure can occur when the lead paint deteriorates or is disturbed by remodelling or scraping.
Until the 1960’s, lead was commonly used in house paint. Homes built and painted before 1960 likely contain the highest levels of lead-based paint. Homes built and painted between 1960 and 1990 may have small amounts of lead in some of the painted indoor surfaces. Higher amounts of lead were used in exterior paints.
Lead-based paint in your home is a serious health hazard if it is:
- chipping or flaking
- within the reach of children who might suck or chew on it, or play with paint chips.
If you have this problem in your home, or if you are planning renovations that will damage painted surfaces, you should remove the paint. It’s important to follow very specific instructions for safely removing old paint. If the paint is in good condition and not on a surface that a child might suck or chew, your risk is minimal. It is best to leave it alone or paint over it.
Lead can be released into the air through industrial emissions, smelters and refineries. Unleaded gasoline was introduced in Canada in 1975 and leaded gasoline was banned in the 1990’s. Lead levels in the air have dropped by more than 99% since 1984, so exposure through the air is less of a concern for most Canadians.
Other sources of lead
Other potential sources of exposure to lead include:
- mouthing or swallowing products that may contain lead, like costume jewellery, art supplies, lead ammunition or fishing weights
- hobbies that involve the use of lead or lead solder, like automotive work or making stained glass, lead ammunition or lead fishing weights
- spending time at a firing range
Workers in smelters, refineries and other industries may be exposed to high levels of lead. Lead dust may be inhaled. It can cling to skin, hair, clothing, footwear and vehicles, and be carried into your home. Most provincial governments require that workers exposed to lead be monitored regularly for lead in their blood.
Reduce your risk
Take these steps to reduce your family’s exposure to lead:
- Run the cold water tap first thing in the morning or any other time the water hasn’t been used for a number of hours. Always use the cold tap water for drinking and cooking, since hot water is more likely to contain contaminants like lead.
- Visit Health Canada’s website and search “lead paint” to access information about paint removal before starting any renovation project in an older home.
- Clean your house regularly to remove dust and particles. This is especially important for surfaces that young children might touch.
- Do not keep food or beverages in lead crystal containers for any length of time. Do not serve pregnant women or children drinks in crystal glasses.
- If you own glazed glass or ceramic dishes bought outside of Canada, do not use them to serve food or drinks. They may have higher levels of lead than are allowed in Canada.
- If you work in a smelter, refinery or any other industry where you are exposed to high levels of lead, protect your family by showering and changing clothes before going home. Get your blood levels checked regularly.
- Never burn waste and old oil, battery casings or wood covered with lead paint, as lead fumes may be released. Dispose of them through your municipality’s Hazardous Waste program.
- If you use lead solder in a hobby, use a good quality breathing mask, keep surfaces clean, and keep children and pregnant women out of the area.
- Wash your hands after handling lead solder.
- Avoid eating animals and birds that were killed with lead ammunition. Use non-lead ammunition when hunting for food.
- Do not store lead fishing weights or other items made of lead where children can reach them.
- Do not allow children to chew or suck on jewellery.
- If you are concerned that you or a family member has been exposed to lead, speak to your family doctor.
- Bushnik T, Haines D, Levallois P, Levesque J, Van Oostdam J and Viau C. Lead and Bisphenol A concentrations in the Canadian population. Statistics Canada, Catalogue Number 92-003-XPE. Health Reports, Volume 21 Number 3, September 2010.
- Centers for Disease Control and Prevention. Sources of Lead. Retrieved November 8th, 2013.
- European Food Safety Authority. Lead dietary exposure in the European population. Journal 2012.
- Health Canada, February 2013. Lead and Human Health. Retrieved November 5th, 2013.
- Ontario Ministry of Agriculture, Food and Rural Affairs, March 2012. Best Production Practices for Producing Safe, Quality Maple Syrup. Retrieved November 8th, 2013.