Calin Lazarescu, Mallory Drysdale, Mylene Ratelle, Kelly Skinner, Brian Laird (2022). Contaminant Exposure and Levels of Lead in Northern Regions of Canada. Proceedings of the GWF Annual Open Science Meeting, May 16-18, 2022.

Lead (Pb) is a toxic element that remains widespread in environmental media (including soil, air, and water) due to anthropogenic releases into the environment. Populations living in Northern communities (including arctic and subarctic areas) face unique environmental challenges, including the so called ‘Arctic Dilemma’. The Arctic Dilemma represents the exposure to environmental contaminants, in Indigenous populations of Northern regions when relying on traditional foods from hunting and fishing, thus, heavy metals, including Pb, are concerns to the health and traditional lifestyles of Northern Indigenous populations.

Research in three areas of Northern Canada: six communities in Dehcho Northwest Territories, Old Crow Yukon, and three communities in Sahtú Northwest Territories, explored concentrations of several contaminants, including Pb. Average blood and urine Pb biomarker levels were found to be higher than those in the general Canadian population (i.e., relative to results from the Canadian Health Measures Survey), in both Old Crow, and the Sahtú. It is not yet clear why levels were elevated and warranting further investigation.

Routes of exposure are being assessed through various methods, including statistical analysis of biomarker and nutrient levels, exposure and food frequency questionnaires, and sampling of water and harvested food. Possible routes of exposure resulting in elevated Pb levels include food and drinking water consumption, hunting practices and other exposure sources, such as smoking.

Statistical analysis of biomarkers in the Sahtu indicated nutrient levels of Zinc, and Vitamin D have significant correlations with Pb levels, and their direction of correlation are contrary to the established physiochemical interactions with Pb. Associations between the consumption of some large animal organs and increasing Pb levels were found in both the Sahtu and Old Crow. Other associations between Pb and determinants such as consumption of daily multi-vitamin (negative association with Pb concentrations) and drinking untreated river (positive association with Pb concentrations) water were also found in Old Crow.

The research generated will directly address community concerns, who have expressed concern in identifying why Pb levels are high and methods in reducing Pb concentrations in the future. The application of a more detailed and specific exposure survey in the Sahtú, and further biomarker statistical analysis are the next steps.

First Author: Calin Lazarescu, School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
Additional Authors: Mallory Drysdale, Mylene Ratelle, Kelly Skinner, Brian Laird: School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada,