Investigation of exposure to metals (including mercury) through the ingestion of piscivorous fish from Lesser Slave Lake for members of Swan River First Nation

Fish is an important traditional food for the Swan River First Nation. Members of the community raised concerns regarding the quality of fish from Lesser Slave Lake given its proximity to industrial activities, specifically  forestry and oil and gas resource developments.

The study objectives were: 1) to measure levels of mercury and other metals in piscivorous fish, such as walleye/pickerel, jackfish and mariah; 2) to administer a dietary survey in order to determine fish consumption patterns;  3) to conduct a human health risk assessment (HHRA) taking into account all the above data and provide community-specific benchmark fish consumption rates for pickerel, jackfish and mariah.

The study found that many of the metal concentrations in the fish were at low or non-detectable levels. Mercury was detected in all of the fish samples analyzed, but except for one jackfish and two pickerel samples, all of the fish caught had mercury concentrations below the Health Canada guideline level for commercial fish of 0.5 ppm.

The study concluded that fish from Lesser Slave Lake was generally safe to eat in the quantities reported by the community members. However, fish consumption advisories issued by Alberta Health have been in place for jackfish and walleye from Lesser Slave Lake for women of childbearing age and children.