Victoria Gevaert, Brian Laird, Mallory Drysdale, Kelly Skinner, Mylene Ratelle (2022). Lipid Adjusted Polychlorinated Biphenyl Levels in Arctic and Subarctic regions in Canada. Proceedings of the GWF Annual Open Science Meeting, May 16-18, 2022.

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants that can be found in northern parts of Canada due to both point-sources as well as long-range transport. Several national biomonitoring projects are collecting data related to PCB and other contaminant exposure levels. However, no recent data is available describing PCB levels among First Nations communities in the Northwest Territories (NWT) and Yukon. Thus, biomonitoring projects were established between 2016-2019 to assess community exposures to several analytes including POPs (e.g., PCBs), metals and pesticides. Researchers developed a community research agreement with community leaders. Blood samples (n=325) from participants in Dehcho and Sahtú, NWT and Old Crow, Yukon were collected and analyzed for fatty acids (DHA+EPA) and PCB levels. Twenty-four PCB congeners and 1 mixture were analyzed and lipid-normalized. Percentiles, geometric means, and limits of detections for all congeners, Arochlor 1260 and certain sums of PCB congeners were generated. Further analyses were conducted for PCBs that had a limit of detection greater than 50%. Independent samples T tests were used to identify significant differences between certain variables (e.g., sex, smoking status, drinking status). ANOVA was used to determine significant differences across the 3 regions. Correlations (Spearman’s ?) explored significant associations between age and omega-3 fatty acid levels. PCB levels appeared to vary across participating regions, with the highest levels appearing among participants from the Sahtú and Dehcho and lower levels in Old Crow, Yukon. Further, PCB levels were generally lower or similar to those in the general Canadian population with the exception of older participants in the Dehcho and Sahtú regions of the NWT. For example, among Dehcho participants 60-79 years, lipid-adjusted biomarkers for select PCB congeners (e.g., PCB 187, 194, 201) appeared significantly higher (up to 1.67-fold) than seen in the CHMS. Similar patterns were observed in the Sahtú region with more PCB congener levels (e.g., PCB 146, 153, 163). PCB levels fell below the previously established health-based guidelines (e.g., actionable levels measured in ug/L)) for PCBs in Canada. PCBs often appeared to differ between men and women , with men showing higher levels compared to women. As age increased, so did PCB concentrations and similar patterns were found with omega-3 fatty acid levels. These results fill a data gap for human biomonitoring in northern Canada. Future research will identify sources of PCB exposure including traditional food intake and assess variability in dietary patterns.

First Author: Victoria Gevaert
Additional Authors: Brian Laird, University of Waterloo , Mallory Drysdale, University of Waterloo, Kelly Skinner, University of Waterloo, Mylene Ratelle, University of Waterloo