Tap water - Prévenir les problèmes de santé reliés à l'environnement

Lead in the tap water of some homes on the island of Montréal

Questions and answers(Français)

Lead in the environment

What is lead and what is it used for?

Lead occurs naturally in small amounts in the earth's crust. Lead can be transformed into a heavy soft greyish inexpensive metal, which makes it useful in the manufacture of many consumer products. In Canada , lead is used mostly to make lead-acid batteries for automobiles. It is also used to make bullets, fishing weights, pipe solder, and x-ray shielding aprons. It is used as well in a number of industrial sectors. (see Table 1).

Lead exposure

How are we exposed to lead?

Lead is present everywhere in nature and is used extensively in consumer products. Consequently, lead is now wide-ranging in our environment: it is found in food, air, water, soil and dust. We are all exposed to small quantities of lead that are absorbed and circulate in our bodies, especially in our blood, bones and certain other tissues. Since lead levels in our environment are very low, average levels of lead measured in people's blood are also low.

However, other sources of lead can expose adults and children to much higher levels and have an impact on their health. If someone has been exposed to high levels of lead, the result can be lead poisoning. Sources of lead can be linked to work, the environment, leisure activities and certain consumer products . The most common sources of lead exposure are listed in Table 1 . Health Canada 's Web site provides a great deal of information on sources of lead exposure to watch for: http://www.hc-sc.gc.ca/ewh-semt/contaminants/lead-plomb/asked_questions-questions_posees_e.html

Table 1 : Most common sources of lead exposure

Related to work naval shipyards battery manufacture and recycling construction/renovation plastics industry glass industry instructors at indoor firing ranges and activities linked to recreational shooting lead industry automobile repair

Related to the environment renovations causing lead paint dust or vapours soils and dust from houses where lead paint is damaged lead pipes

Related to recreational activities glazes used in pottery indoor shooting ranges preparation of lead bullets or fishing weights stained glass fabrication renovations that involve working on old lead paint furniture restoration that includes working on old lead paints art projects using paint that contains lead pigment automobile or boat repair

Related to consumer products Kohl make-up or Surma (Kohl: http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/2005/2005_103bk2_e.html ) Some traditional medicinal products ( http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/2005/2005_09_e.html ) Some imported tableware (earthenware http://www.hc-sc.gc.ca/cps-spc/advisories-avis/aw-am/moroccantagines_e.html , lead crystal ware http://www.hc-sc.gc.ca/iyh-vsv/prod/crystal_e.html ) Some low-cost horizontal mini-blinds ( http://www.hc-sc.gc.ca/ahc-asc/media/nr-cp/1996/1996_48_e.html ) candles with lead core wicks ( http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/2001/2001_02_e.html ) Some children's jewellery ( http://www.hc-sc.gc.ca/cps-spc/pubs/cons/jewellery-bijoux_e.html )

What does the Montréal Public Health Department do when there are cases of lead poisoning?

In Québec, a doctor who suspects there has been significant exposure to lead can have a patient's blood lead levels measured. If results show that lead concentrations are higher than the public health intervention level (100 micrograms per litre of blood), the doctor and the laboratory that performed the analysis are required to report this result to the Public Health Department. The role of the Public Health Department then consists in checking the patient's living environments (home, school, work or recreational activities) to see if there is a specific source of lead that could explain the levels measured and whether it could be a source of significant exposure for other people. When this source is identified, control measures must be introduced to eliminate it.

Old peeling or chipping lead paint (windowsills, cribs, dust from renovations, etc.) and certain traditional make-up products (kohl) are the main sources of lead exposure linked to cases of poisoning among children living on Montréal Island . Moreover, it has been noted that children who have recently arrived in Canada may have been exposed to high levels of lead in their countries of origin. Tap water has never been identified as a source of lead exposure in any reported cases.

Are we more exposed to lead now than we were in the past?

No. At this time, we are much less exposed to lead than we were in the past. Indeed, numerous sources of lead exposure that were formerly in our environment have been reduced or eliminated: during the last few decades, enforcement of stricter standards had made it possible to almost totally eliminate lead in gasoline, food cans, paint, lead solder and other items.

These measures have been very effective and people's exposure to lead in the air, and in food, water and other consumer products has been reduced substantially. Consequently, the blood lead levels of children have also diminished, from about 200 micrograms per litre in 1972 to less than 30 micrograms per litre today ( Figure 1 ).

Figure 1 : Reduction of average blood lead levels in Québec children over the past decades

 

Lead in drinking water

How can lead get into my tap water?

Drinking water produced by the city of Montréal and distributed to residents through its aqueduct system contains practically no lead and conforms with provincial regulations. The physical and chemical characteristics of the water distributed in Montréal do not foster lead dissolving in water . Rather, lead can dissolve into tap water when water flows through lead service connections that link some homes to municipal water mains ( Figure 2 ). In these cases, hot water and water from taps that have not been turned on for a while (in the morning or after returning home from work) tend to contain higher concentrations of lead.

Connections between homes and municipal water mains have two sections: a private section located between a house and the service connection, which is the responsibility of the homeowner; and a public section located between the service connection and the municipal water main, which is the responsibility of the municipality ( Figure 2 ).

Figure 2  : Location of service connections between a home and a municipal water main

 

What are the maximum lead concentration levels allowed in provincial drinking water?

In Québec, the Regulation respecting the quality of drinking water states that the lead content in tap water must not exceed 10 micrograms per litre (10 µg/L) ¹ after letting the water run for at least 5 minutes. Before 2001, the standard was 50 µg/L. It was lowered to 10 µg/L to conform to a Canadian recommendation issued in 1992.

Why was the standard for lead in drinking water lowered in 2001?

The standard for lead in drinking water was lowered in 2001 to proceed with actions designed to lower Québeckers' exposure to lead, similar to previous actions that had also significantly reduced or almost completely eliminated lead in gasoline, food cans, paint, lead solder, and other items .

Lead in drinking water in Montréal

Why is action being taken now in relation to lead in tap water on the Island of Montréal ?

Drinking water distributed through municipal water systems on the island of Montréal is of good quality and contains almost no lead.

Data collected in 2005-2006 showed that the tap water in the majority of homes on the island of Montréal meet the new provincial standard of 10 µg/L of lead in tap water. However in some homes of fewer than 8 living units built prior to 1970 and linked to the municipal aqueduct system through a lead service connection , the tap water may exceed the standard of 10 µg/L while still meeting the previous standard of 50 µg/L.

The Montréal Public Health Department considers the risks to the health of the residents in these homes to be low and limited to pregnant women (because of their foetuses) and to children under 6 years of age. Nonetheless, it felt compelled to ensure that citizens affected by this situation be informed and adopt preventive measures that can reduce their exposure to lead to a minimum.

Can levels that exceed the standards be attributed solely to having lead solder in indoor plumbing?

No. On the Island of Montréal, although lead solder in indoor home plumbing can cause lead to dissolve in tap water, it does not result in lead levels exceeding the standard of 10 µg/L after the water has been running for at least 5 minutes. In fact, a few years after this type of solder is installed, a protective film forms inside the pipes that limits dissolution of lead solder in the water. Moreover, the material used to solder pipes has contained almost no lead since 1989 (less than 0.2%).

What are the health effects of lead exposure ² ?

The initial health effects observed in young children when blood lead concentrations exceed the standard (100 micrograms per litre of blood) and that must be reported by doctors and laboratories are neurobehavioural in nature (a child's learning capacity and intellectual development are affected). Based on lead concentrations measured in the tap water of homes with lead service connections to the municipal water main, the Public Health Department estimates that the blood lead levels of children who drink this water do not exceed 100 micrograms per litre, unless they are also exposed to other significant sources of lead. Indeed, in Montréal, such blood lead levels linked to drinking water have never been reported.

The health effects of lead observed when blood lead levels are much higher affect other systems in the body, such as the blood, digestive, kidney and nervous systems. However, we are not worried about these health effects developing as a result of the lead concentrations measurements in the tap water of homes with lead service connections to the municipal water main on the island of Montréal .

What does the Montréal Public Health Department recommend to people who live in homes with lead service connections to the water main?

The Montréal Public Health Department considers that the health risks are low and limited to pregnant women (because of their foetuses) and children under 6 years of age who live in homes of fewer than 8 living units built prior to 1970 and linked to the municipal aqueduct system through a lead service connection. Indeed, these children's blood lead levels may be slightly higher than the average for Québec children. However, these levels are much lower than the levels that all Québeckers now over the age of 30 had when they were young.

However, to reduce to a minimum the low risks to health, the Public Health Department recommends that pregnant women and parents of children under 6 years of age consider using a filter attached to the tap or a pitcher water filtration system ² (certified as meeting the NSF International Standard for reducing lead in conformance with NSF/ANSI standard n°53 ³ and available on the market), or drinking bottled water. This precaution is particularly important for infants being fed with commercial milk preparations that are reconstituted with water (concentrated or powdered formula). By following this recommendation, parents may be assured that the total exposure of their children to all sources of lead will be similar to that of other Québec children.

However, if it has been confirmed that your tap water does not exceed the new standard of 10 µg/L after running for at least 5 minutes , you do not have to follow the Montréal Public Health Department's recommendation.

The Montréal Public Health Department would like to remind the public that no case of blood lead levels exceeding the standard has ever been reported by a doctor or laboratory.

What are the measures recommended by the city of Montréal ?

The city of Montréal recommends to a lways let the tap water run for a few minutes after until it has turned cold (cool in summer) before drinking it, especially if the water has been in the pipes for several hours (for example, in the morning or after returning home from work).

You can find more pertinent advice on the city of Montréal 's Web sit at http://www.ville.montreal.qc.ca/drinkingwater , then click on English.

I live in a home whose connector linking the house to the municipal water main is not made of lead. Do I have to follow the recommendation of the Montréal Public Health Department?

No. The lead content in your tap water does not exceed the new provincial standard of 10  µg/L .

Why has a specific recommendation been issued for pregnant women, infants and children under 6 years of age?

The Montréal Public Health Department's recommendation is only for pregnant women, infants and children under 6 years old. Indeed, we know that infants are more vulnerable to the toxic effects of lead and they can be exposed notably through commercial milk preparations reconstituted with tap water (concentrated or powdered formula). Young children are also vulnerable given that they absorb lead more effectively than do adults, are at higher risk of dietary deficiencies that facilitate lead absorption, and are more sensitive to the haematological (blood) and neurological effects of lead than are adults. During pregnancy, lead that has accumulated in the bones goes back into the blood stream. The foetus is considered to be more vulnerable because during pregnancy, some of the lead that has accumulated in the mother's body passes through the placenta and reaches her unborn child. However, the mother must have a high blood lead level herself to pose a risk to her foetus.

I feed my child commercial milk preparations reconstituted with water. Should I keep using tap water?

If you live in a home where the connection that links your house to the municipal water main is made of lead, you should consider using either a filter installed on the tap or a pitcher water filtration system⁴ (certified as meeting the NSF International Standard for reducing lead in conformance with NSF/ANSI standard n°53 ⁵ ), or using bottled water to reconstitute commercial preparations of concentrated or powdered formula for infants . If you use tap water, lead concentrations could be higher than average for your child than for other Québec children, given that milk makes up a large part of your child's diet and he or she does not weigh as much as older children. If you follow this recommendation until you are sure that the lead concentrations in your tap water meets the new standard of 10 µg/L, you will be sure that your baby's total exposure to lead will be similar to the average exposure of all babies in Québec.

I live in a house with a lead connection to the municipal water main and I am breastfeeding my child. Should I consider using a filter or drinking bottled water?

No. The amount of lead found in the breast milk of women who drink the tap water in these homes does not constitute a risk to their infants' health.

I live in a house with a lead connection to the municipal water main and my children have been drinking tap water since they were born. Should I be afraid for their health?

No. An evaluation conducted by the Montréal Public Health Department of the health impacts of lead concentrations measured in the tap water of these homes was reassuring : we do not think that blood lead levels in children who have drunk tap water were higher than the public health intervention level of 100 micrograms per litre of blood. We are also convinced that their blood lead levels are lower than the levels that all Québeckers now over the age of 30 had when they were young (200 micrograms per litre in the 1970s, illustrated in Figure 1). Indeed, these individuals were exposed to much higher lead levels through the air they breathed and the food they ate. For example, cans of commercial ready-to-serve milk preparations had lead solders with average lead concentrations of 70  µg/L, which is higher than the previous standard of 50 µg/L for lead in drinking water. In addition, children who were breastfed ingested a higher level of lead through breast milk than today's infants since the average blood lead level of mothers was also higher (96 micrograms per litre of blood instead of today's figure of about 20 micrograms per litre of blood).

I live in a house with a lead connection to the municipal water main. Should I have my child's blood lead level measured?

No. Based on the lead levels measured in the tap water in these homes, there is no reason to have your child's blood lead level measured, unless there is another significant source of lead in his or her environment (table 1).

Can I take a bath or shower, and wash my clothes and do the dishes using tap water?

Yes. Even if you live in a home where the connector to the municipal water main is made of lead, you can use tap water to take a bath or shower, wash your clothes and do the dishes. These activities do not expose people living in the house to lead.

What are municipal authorities doing to solve the problem of lead in tap water?

The city of Montréal and the other cities concerned ⁶ are committed to eliminating all lead service connections on the island of Montréal over the next 20 years. They are also encouraging homeowners to replace the private sections that link their homes to the water main. If we want to permanently solve the problem of lead levels in tap water exceeding the standard, we must replace all lead pipes (public sections, between street and service valve, and private sections, between service valve and home).

The city of Montréal will keep residents informed about issues related to connections to the municipal aqueduct system and about prevention methods to use to reduce to a minimum children's exposure to lead.

Residents can call the city of Montréal 's WATER INFO LINE at 514-868-4483 or visit the city's Web site at (http://www.ville.montreal.qc.ca/drinkingwater).