In October 2019, the Government of Quebec asked all schools and child care services to check the amount of lead in water that children might drink. Action must be taken if the amount of lead in water exceeds the new standard of 5 micrograms per litre (μg/L). The Government is aiming for the lowest possible exposure to lead in drinking water in schools and child care services. For more information, see the section ”Possible health effects of lead in water in schools and child care services” and the page Plomb dans l’eau des écoles (Lead in water in schools, in French only).
Lead is a metal that is known to have long-term adverse health effects. Although lead exposure is considered to be very low today, no safe blood lead level has been identified. This is why public health authorities worldwide recommend reducing exposure to the lowest reasonably possible level, taking the context into account. To find out more, go to the Reducing exposure to lead page.
Lead is a metal found in small amounts in our environment, including in water, air, soil and consumer products. The entire population is exposed to low levels of lead.
When a person is exposed, the lead absorbed by the body is transported by blood to the bones and some organs, such as the brain and kidneys. Although some of the lead is excreted in urine and stool, a significant amount accumulates in bones and teeth over time. Lead concentrations can vary widely from person to person depending on a number of factors, such as smoking. With aging and decreasing bone mass, the lead that has been stored is released back into the bloodstream. It takes around 25 years for the body to excrete half the accumulated lead.
Nowadays, adverse effects from short-term (acute) lead exposure are very rare. Indeed, severe measures have been put in place in workplaces, for instance, where lead exposure could occur.
The symptoms observed with chronic lead exposure vary widely and are not specific. Lead exposure is not detected by the presence of symptoms, but during preventive workplace health screening.
Vunerable people and health risks
Lead is harmful for everyone’s health, regardless of age. However, some population subgroups are particularly susceptible to the effects of exposure, even to low levels of lead in the environment. Some are also at higher risk of lead exposure:
- Fetuses, infants and children
- Pregnant women
- People with significant bone mass loss (in particular, older adults)
- People who use products that contain lead
- People who eat game meat contaminated with lead ammunition
- People who use or make their own lead ammunition
- People who work in environments where lead is found, such as:
- The recycling sector
- Indoor and outdoor firing ranges
- Families exposed to contaminated clothes and material brought into the home by a worker
Fetuses, infants and children
Fetuses, infants and children absorb more lead than adults. They are particularly vulnerable and sensitive to the effects of lead on their nervous system, because they absorb lead more easily and their brain is developing. Mild effects on learning skills have been reported in children who often drink water that contains lead.
The neurological effects of long-term lead exposure in children are:
- A slight decrease in intellectual ability
- Attention problems, such as attention deficit disorder
- learning problems, such as difficulty reading (dyslexia)
- Behavioural changes, such as decreased concentration, irritability and apathy, that is, indifference to emotion, motivation or passion
During pregnancy, there is a risk of exposure for the fetus. Indeed, lead in the mother’s body can easily cross the placental barrier. Lead stored in bones is released, especially in the third trimester. This means that women’s blood lead levels may increase during pregnancy and affect the fetus. Increased lead exposure in pregnant women can lead to low birth weight and damage the baby’s brain, kidneys and nervous system.
Infants are exposed to low levels of lead in breast milk. Except in exceptional situations, the benefits of breastfeeding for infants outweigh the low risk of health effects. However, it is important to respect the mother’s choice of feeding method for her baby.
Preschool children are vulnerable because they play or crawl on the ground. Their main routes of exposure are soil and the ingestion of house dust, since they have the reflex to put in their mouth everything that comes to their hand. Exposure to lead therefore comes mainly from dust, food and drinking water. These sources contribute to the low levels of lead present in the blood of all children.
Children’s exposure to lead is much lower nowadays. The efforts made to discontinue the use of lead in paint, gasoline and plumbing have contributed to this reduced exposure.
The risk is lower for children age 6 and over and adults. Their bodies absorb less lead than young children.
When to consult
If you think you have been exposed to high levels of lead during an activity or at work, share your concerns with your doctor.
Depending on the situation, the doctor may be able to do a blood test (blood lead test) to see if you have been exposed to excessive levels of lead and if certain measures need to be taken to quickly reduce your blood lead levels.
If your blood lead levels are high, treatment to speed up the removal of lead from the body may be recommended. The type of treatment varies depending on your blood lead levels and your health condition. In all cases, potential sources of lead in the environment must be identified and removed in order to reduce your lead exposure.
In Québec, lead exposure is a reportable disease of chemical origin. If your blood lead level is above the public health threshold, your doctor is required to report the situation to the public health authorities in your region in order to help identify the source(s) of exposure and make sure that other people around you are not exposed.
There is no person-to-person transmission. Only a source of exposure in the environment, food or water can, over a long period of time, cause your blood lead levels to increase.
Protection and prevention
Trace amounts of lead can be found everywhere in our environment. Even if the main sources of contamination have been removed, such as lead in gasoline, paints and solder used in food cans, minimizing lead exposure is nonetheless recommended. To find out more about sources of exposure and the precautions to take, go to the Reducing exposure to lead page.
Possible health effects of lead in water in schools and child care services
Drinking water in schools and child care services is one of many sources of lead exposure. In general, the risk of health effects from lead in water in school and child care services is low, since:
- Most of the time, the amount of lead decreases or disappears after letting the water run a little.
- Children drink less water at school or child care than at home.
- As a precaution, the water in schools or child care services is tested when the amount of lead is expected to be at its highest (after it has been stagnant for a long time). The results of these tests do not represent what children drink the rest of the day.
No medical follow-up is needed for your child in connection with lead in water in schools and child care services and they do not need a blood test for this type of lead exposure. The Direction régionale de santé publique will notify the parents concerned if special follow-up is required.
Last update: October 25, 2021