The Naskapi Nation community has historically relied on subsistence hunting, fishing, and trapping for their food supply. The members of Naskapi Nation raised concerns about the potential impacts of mining activities (current and abandoned iron mines) near their traditional territory on both the environment and human health. The overarching objective of this study was to undertake a community-based monitoring study to determine concentrations of heavy metals in fish and waters of Naskapi Nation's traditional territory.
This study included a sampling program of local freshwater fish tissues (lake trout, brook trout and whitefish) as well as water and sediment from Lake Attikamagen, Lake Astray and Lac Vacher for analysis of heavy metal concentrations. A dietary survey was administered to gather information on fish consumption patterns. The collected data were used to assess potential risks of exposure to heavy metals from fish consumption.
The results of this study showed that water samples had low levels of heavy metals and were not of any concern. Sediment samples from Iron Arm and Lac Vacher had elevated levels of arsenic and sediment samples from Iron Arm also had elevated levels of cadmium. The high arsenic and cadmium levels in the sediment, however, did not translate into levels of concern in fish tissue. The concentrations of mercury in lake trout were often higher than the Health Canada guideline of 0.5 ppm, whereas no whitefish samples exceeded the Health Canada guideline limit. This finding was not unexpected because larger and predatory fish tend to have higher mercury levels because of bioaccumulation. The results of the dietary survey confirmed the importance of fish in the Naskapi diet, especially lake trout.
Based on these findings, the study highlighted the need to develop community-specific fish consumption recommendations in order to minimize mercury exposure while continuing to promote the benefits of harvesting and consuming fish. The authors suggested that future research is needed to: 1) examine mercury levels in blood and/or hair samples to confirm whether dietary exposure is putting community members at risks of any negative health effects, particularly children and women of childbearing age; 2) conduct a more comprehensive dietary survey that would include other potential sources of mercury in the diet; and 3) repeat the monitoring of mercury levels in fish from Naskapi fishing lakes to assess whether the risk of dietary mercury exposure is improving or worsening with time.