While lead (Pb) is a naturally occurring element found in rock and soil, extensive man-made use has resulted in its widespread presence in the environment. Environmental lead concentrations are extensively measured and reported by national, provincial, and municipal initiatives across Canada. Lead is found in air, dust and soil in Canada as well as in food and drinking water. Levels of lead in the environment have declined significantly over the past few decades.
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Health Canada published a Final Human Health State of the Science Report on Lead (SOS) and a Risk Management Strategy for Lead (RMS) in February 2013.
The drafts of these reports were released on July 26, 2011 and were subject to a 60-day public comment period. The comments and responses received during the public comment period have been summarized in a public comment table . The final SOS report incorporates comments received during the public comment period; new data from Canadian exposure studies; and findings from draft reports by international organizations which were not available at the time of publication of the draft SOS.
Canadians are exposed to low levels of lead through food, drinking water, air, dust, soil, and products. Although blood lead levels (BLLs) have declined by over 70% in Canada since 1978-1979, lead is still widely detected in the Canadian population.
After the implementation of measures to reduce exposures to lead through inhalation (e.g., prohibition of leaded gasoline), oral exposure from food and water now represents the most significant route for the general adult population. For infants and children, ingestion of non‑food items containing lead (such as dust, lead-based paint, soil and products), along with food and drinking water, are the greatest sources of exposure to lead in the environment.
Although BLLs of Canadians have declined significantly over the past 30 years, there is new scientific evidence that health effects are occurring below the current Canadian blood lead intervention level of 10 μg/dL. There is sufficient evidence that BLLs below 5 μg/dL are associated with adverse health effects. Health effects have been associated with BLLs as low as 1-2 μg/dL, levels which are present in Canadians, although there is uncertainty associated with effects observed at these levels. While Canadian BLLs are among the lowest in the world, it is considered appropriate to apply a conservative approach when characterizing risk. Accordingly, additional measures to further reduce lead exposures to Canadians are warranted.
Research and monitoring will continue to support the assessment of lead in Canadians and, where appropriate, assess the performance of potential control measures identified during the risk management phase.