Lead in drinking water

Source: MSDEP

Lead in drinking water

Given the importance the Department places on this, significant changes to the regulation respecting the quality of drinking water (RQEP) in connection with the control of lead and copper in drinking water came into force on 8 March 2013. These changes focus on the number of samples to be collected annually and at sites where samples must be carried out.

In addition, an evaluation guide and intervention in relation to the monitoring of lead and copper in drinking water in draft for consultation was published on the Department's Web site. This guide aims to help managers of a system of drinking to meet the requirements of RQEP water, to assess the extent of the problem when results showed lead levels above the standard, identify service entrances lead that may be present on their distribution system and implement the solutions to the problems raised.

In this section you will find a variety of relevant information about the presence of lead in drinking water in Quebec in the form of questions and answers by topics and a summary of sampling campaigns conducted in 2006 and 2007.

Lead: A health risk?

Lead is known to have adverse effects on human health. At low concentrations, it mainly affects the nervous system and can cause minor effects on the intellectual development of infants and children under 6 years. They are more vulnerable because they are growing. The same is true for the fetus of pregnant women.

Although lead exposure has been reduced dramatically in recent decades, there is a broad consensus to maintain public health efforts to reduce as much as possible.

You can consult the Health Canada website for more information on the effects of lead exposure on human health (reducing your exposure to lead and Commonly Asked Questions about the effect of lead exposure on human health).

Sources of lead exposure

Lead is a heavy metal grayish present naturally in small amounts in the earth's crust. It is also used in many consumer products, so that we are all exposed through food, water, air, dust and soil.

Many measures have been taken by governments to reduce population exposure to this metal either by ingestion or inhalation. Thus, over the past thirty years, a decrease in blood lead (lead concentration in the blood) is observed in the Quebec population. Formerly, there were particular lead in gasoline, paint and solder tin cans and some components of drinking water pipes may still contain.

Where can come lead being found in drinking water?

Lead found in drinking water comes from some components of the distribution system. The main sources of lead service entrances lead (line connecting the building to the municipal pipes) or internal plumbing of the building (lead solder, old lead pipes, plumbing fixtures, etc..).

Service entrances lead were used in drinking water pipes at the beginning of last century. The advent of copper, after the Second World War, came to change this practice, so that the use of inputs lead service has gradually disappeared and was banned by the Plumbing Code in 1980.

Moreover, in 1989, the Plumbing Code prohibits the use of solder containing more than 0.2% lead. As we still find the welding wire with more than 0.2% lead on the shelves of hardware stores, it is still possible today to find welds with a high lead content. However, lead solder can gradually lose the ability to release lead after a few years.

Still inside homes, plumbing fixtures, such as faucets and water meters, can be sources of lead in water. Finally, it may be found that the lead pipes in very old houses, but this is exceptional.

Despite these different sources of lead, which can vary greatly from one residence to another, the presence of lead in tap water also depends on the nature of the water supply and use. Indeed, the concentration of lead in tap water is influenced by the ability of the water to cause the dissolution of lead with which it comes in contact (aggressiveness and water temperature). The lead concentration also depends on the duration of standing water in the pipes before opening the tap and the time when it leaves the water running before filling his glass.

Where do we find service entrances lead in Quebec?

According to information available to the Ministry, service entrances lead may have been installed in the majority of regions of Quebec until 1955, until 1967 in the Montreal area and until 1971 in the Laurentian region. Only the Gaspésie, Bas-Saint-Laurent, Îles-de-la-Madeleine, Côte-Nord and Nord-du-Québec would be little or not affected by this issue. A report commissioned by the Department in 1994 estimated the number at 100,000 in Quebec municipalities excluding Montreal.