Levels of metals and persistent organic pollutants in traditional foods consumed by First Nations living on-reserve in Canada

Objectives First Nations may have a higher risk of contaminant exposure from the consumption of traditional foods. The objective of this study was to measure concentrations of metals and organochlorines in traditional foods commonly consumed by First Nations in Canada and estimate the risk from dietary exposure. Methods Data were collected from the participatory First Nations Food, Nutrition and Environment Study (2008-2018). Traditional food samples were collected by community members and concentrations of metals and organochlorines were measured. The population-weighted mean daily contaminant intake from traditional food items was estimated. Hazard quotients (HQs) were calculated by dividing contaminant intake with the toxicological reference values (TRVs). Results A total of 2061 food samples (different parts and organs) from 221 species were collected. The highest concentrations of cadmium were found in the kidneys of land mammals: moose kidney was the most significant contributor to intake. The meat of land mammals and birds had the highest lead concentrations and were the most significant contributors to intake. Arsenic was highest in seaweed, and prawn was the most significant contributor. Mercury and methyl mercury were highest in harp seal meat, with walleye/pickerel contributing most to intake. Harp seal meat also had the highest p,p'-DDE and PCB concentrations, and ooligan grease and salmon were the most significant contributors to intake. The percentage of adults eating traditional food who exceeded the TRVs was 1.9% for cadmium, 3.7% for lead, 13.6% for arsenic, 0.7% for mercury, and 0% for p,p'-DDE and PCBs. All median HQs, and most 95th percentile HQs, were less than 1. Conclusion These results can be used as a baseline of contaminant levels and exposure in traditional foods for future monitoring programs and to support risk assessment programs.

Automated summary

The study found that traditional foods commonly consumed by First Nations in Canada contain various harmful substances, with some metals and organochlorines exceeding toxicological reference values in terms of intake.