Mitigating the contaminated source of traditional foods with an uncontaminated river system

Residents of Seine River First Nation (SRFN) have been dependent on fish and gathered foods provided by the Seine River Watershed (SRW). However, previous studies have revealed serious concerns associated with using food from this system. The SRFN wished to investigate whether the Turtle River Watershed (TRW) could be used as an alternative source of traditional foods.

This project collected baseline water, soil, plant, invertebrate and sediment samples from water bodies on the TRW to measure levels of heavy metals, including mercury, and compare these levels to those from the SRW. A dietary survey was administrated to gather information on traditional food consumption. In addition, hair samples were collected from community members to determine the body burden of mercury.

The study showed that, overall, the levels of heavy metals in fish species were low. However, levels of mercury in fish varied considerably, both within and between lakes. The highest mercury concentrations were found in predatory fish species (northern pike, walleye, muskie and bass) while the lowest mercury levels were detected in whitefish and sturgeon. Contaminants in other important natural food sources such as blueberries and wild rice were low and consumption of these foods does not represent a concern. Concentrations of mercury in human hair were all found to be below the Health Canada biomonitoring guidelines.

The study concluded that the TRW cannot be considered as a replacement to the SRW for traditional food. Rather both watersheds need to be prioritized for their individual benefits. The consumption of large predatory fish species was not recommended for the sensitive population, including pregnant women, women of childbearing age and children, while whitefish, sturgeon, red horse bass, suckers were safe to eat in any quantities. The study recommended that a community awareness program should be implemented to make residents aware of the risks and benefits of fish consumption.