Lead, mercury and cadmium levels in Canadians

by Suzy L. Wong and Ellen J.D. Lye

Abstract

The Canadian Health Measures Survey (CHMS), the most comprehensive direct health measures survey ever undertaken on a national scale in Canada, includes measurement of the heavy metals, lead, mercury and cadmium, which are toxic to humans at excessive levels. The geometric mean blood concentrations for lead, total mercury and cadmium were 1.37µg/dL, 0.76µg/L, and 0.35µg/L, respectively.  Blood lead concentrations have fallen substantially since 1978, when national levels were last measured. Much of this decline may be attributed to the phase-out of leaded gasoline, lead-containing paints and lead solder in food cans since the 1970s.  Fewer than 1% of Canadians now have blood lead concentrations above the Health Canada guidance value of 10µg/dL. Similarly, fewer than 1% of Canadian adults have total blood mercury concentrations above the Health Canada guidance value of 20µg/L for adults. CHMS data will be used to assess current population levels for a broad range of environmental chemicals, chronic diseases, nutritional status and infectious diseases; to provide a baseline for emerging trends, and to enable comparisons with other countries.

Keywords

biomonitoring, body burden, Canadian Health Measures Survey, environmental exposure, environmental pollution, heavy metals, public health

The data

Estimates are based on data from the Canadian Health Measures Survey (CHMS). During an in-home interview, demographic and socioeconomic data and information about lifestyle, medical history, current health status, the environment, and housing characteristics are collected. At a mobile clinic, physical measurements, such as blood pressure, height, weight and physical fitness are assessed. Blood and urine samples are taken to test for infectious diseases, nutritional status, cardiovascular disease risk factors, and levels of environmental chemicals, including heavy metals. [Full text]

Findings

The heavy metals lead, mercury and cadmium are widely dispersed in the environment, and at excessive levels, are toxic to humans. Chronic exposure to these substances may also be hazardous. Although these metals occur naturally, exposure may be increased by human activities that release them into the air, soil, water and food, and by products that contain heavy metals. [Full text]

Authors

Suzy L. Wong (613-951-4774; Suzy.Wong@statcan.gc.ca) is with the Health Information and Research Division at Statistics Canada, Ottawa, Ontario, K1A 0T6. Ellen J.D. Lye (613-952-3496; ellen.lye@hc-sc.gc.ca) is with the Risk Management Bureau, Chemical Management Directorate at Health Canada, Ottawa, K1A 0K9.