Examining the Presence of Contaminants in Wildlife and Plants

Phase 2 of this study was designed to build upon phase 1 and address the concerns of the Takla Lake First Nation (TLFN) and Tsay Keh Dene (TKD) communities regarding the impact of environmental contaminants caused by past and present industrial activity on their traditional territories.

Interviews were conducted, in which participants were asked to identify potentially contaminated sites and specify the types of plants and animals that they would like to have sampled for analytical testing. A food frequency questionnaire (FFQ) was also administered to document how often and in what quantities traditional foods were being consumed in the two territories. Samples of water, surface soil layers, plants, and animals were collected and analysed for the presence of trace elements, such as mercury and other heavy metals, as well as pesticides and hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). The plants that were sampled included various herbs and medicinal plants that were important to the First Nations way of life. Tissue samples were collected from fish, birds, and mammals that were commonly consumed by the TLFN and TKD communities.

Based on the study findings, some soil and water samples showed elevated levels of trace elements such as barium, arsenic, antimony, cadmium, chromium, copper, iron, lead, manganese, molybdenum, nickel, selenium, vanadium and zinc. Certain soil samples were also found to have concentrations of light extractable petroleum hydrocarbons (LEPH) and heavy extractable petroleum hydrocarbons (HEPH) that exceeded the B.C. Contaminated Sites Regulations criteria for agricultural and residential or parkland soils. Several fish tissue samples had elevated levels of mercury but low levels of PAHs and other trace elements. Mercury levels were higher in older, larger, predatory fish. The concentrations of trace elements in moose were consistently low across sampling locations. In addition, low levels of metals and PAHs were seen in other species of wild game. The slightly elevated concentration of lead in the breast muscle of a mallard duck may have been due to contamination from lead gun shot. Some berries from TLFN and TDK territory showed slightly higher concentrations of chromium and manganese than other berries tested in this study, while Saskatoon berries from two sites showed higher concentrations of barium and boron.

This study authors suggested that further studies should be conducted to demonstrate a direct link between industrial contaminants and human health by testing hair samples for mercury. These studies should also include an educational component to inform community members about the various environmental contaminants that may associated with industrial activity.