[ARCHIVED] Systematic Review of Human Biomonitoring Studies of Environmental Contaminants

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This review synthesizes information on biological markers of exposure to environmental contaminants in Canada through a systematic search of the published and grey literature from January 1990 to January 2007, evaluates the studies, and summarizes the information in an easy access format. This review will make the Canadian work on biomonitoring for environmental contaminants more accessible to public health practitioners and assist with interpretation of biomonitoring results, their validity and significance in practice.

This report includes reliable information on biomonitoring for environmental contaminants in Canada. For most studies, information collated in this report could not be used to calculate “background levels” because most of the measurements are not systematic or randomly selected from the general population. Given these limitations, the studies are not generalizable to the general population. Notwithstanding, the levels reported here can guide public health practitionersin the interpretation of values obtained in their selected populations and can be used in the communication of risks to local situations involving environmental contamination. “Background levels” of some contaminants (Cd, Se, Pb, Mn, MeHg) have been reported for large populations and, where applicable, were provided in this report.

Some important issues arose out of this review. Biomonitoring is considered a reliable measure of population-based exposure tracking environmental contaminants exposure. Very few studies in this database have utilized random sampling techniques which reflect the full range of overall population exposures. As a result, we do not have quantitative measures of population exposure to most contaminants. At best, studies used sample frames that reflected a priori populations at risk. Most often, sample frames were convenience samples. Serial analyses for contaminants in singular populations or in cohorts are not common, but are most useful in interpreting declines in contaminant concentrations after interventions. The process of obtaining, storing, transporting, and analyzing biological specimens is complex. Studies require careful ethical oversight, and interpretation of results is not always meaningful for the participant. These appear to be major challenges for the conduct of these studies.