Teslin Sewage Lagoon Remediation Project
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Overview
The Teslin Sewage Lagoon project is part of the Government of Canada’s ongoing work to address contaminated sites under the Federal Contaminated Sites Action Plan (FCSAP).
Located within the Traditional Territory of the Teslin Tlingit Council’s (TTC) in the Village of Teslin, Yukon, this site is covered by the Yukon Devolution Transfer Agreement managed in partnership with the TTC.
The project’s goal is to ensure the long-term protection of the environment and community health through the proper reclamation and closure of the historic lagoon and associated debris areas.
Background
Site history
The Teslin Sewage Lagoon was constructed in the 1950s or 1960s to service the Village of Teslin. It is an unlined pond approximately 40 metres long by 10 metres wide. The lagoon was decommissioned in 1977 during the construction of the municipal sewage lagoon and has remained largely unused since.
The site covers approximately 6.4 hectares and is mostly forested land. It is located north of Ward Street, across from the highway maintenance depot and works yard, about 200 metres northeast of the Teslin Airport, and approximately 180 kilometres southeast of Whitehorse, Yukon.
The former sewage lagoon was situated within an area designated as part of the Teslin Aerodrome, where military activities took place during and shortly after World War roman numeral 2. Due to its historical uses, the lagoon likely contains various residential, commercial, and industrial contaminants.
Previous assessments
In 2004, following the devolution of federal aerodrome facilities, the Government of Yukon began assessing environmental risks, including conducting a Phase roman numeral 1 Environmental Site Assessment (ESA) of the Teslin Aerodrome.
A Phase roman numeral 1 Environmental Site Assessment (ESA) conducted in 2018 by Hemmera identified three Areas of Potential Environmental Concern (APECs):
- Sewage Lagoon (APEC 1)
- Fill and Debris Area (APEC 2)
- Highway Maintenance Depot and Works Yard (APEC 3 – off-site)
Environmental Site Investigations
In 2021, ERM Consultants Canada Ltd. completed a Phase roman numeral 2 of an ESA to further investigate potential contaminants of concern identified in 2018.
Key Findings
- Six boreholes were drilled, and monitoring wells were installed to collect soil and groundwater samples.
- All soil and groundwater results were below the applicable standards of the Canadian Council of Ministers of the Environment and the Yukon Contaminated Sites Regulation, except for naturally occurring metals (chromium, nickel, manganese) consistent with background levels.
- No significant contamination was detected in the sewage lagoon or debris areas.
- Recommendations include:
- Additional seasonal sampling of the monitoring wells to confirm results.
- Sampling of lagoon water and sediment to assess whether it may be a potential ongoing source of contamination.
Current and Upcoming Work
Projects in 2023–24
- Completion of an engineering report to evaluate reclamation options.
A monitoring report prepared in 2023 by ERM for the Teslin Tlingit Council (TTC) identified metal exceedances in lagoon surface water and sediment relative to federal aquatic life guidelines. However, the water and sediment appeared contained, and no immediate action is required unless directed by a future Land Use Plan. If necessary, lagoon water and sediment could be removed for off-site disposal.
Although a Land Use Plan has not yet been completed, the TTC intends to assess decommissioning options to reduce environmental risks in line with good land use practices. A Construction Work Plan has been developed to infill the former lagoon, following disposal of surface water and sediment and to reduce the risk of surface water migrating off-site. After decommissioning, the area is expected to remain a 'functional;’ however, further considerations will be required should the site be developed for other purposes involving frequent human activity.
Projects in 2024–25
- Preparation of regulatory submissions under the Yukon Environmental and Socio-economic Assessment Act
- Completion of decommissioning and site reports
Projects in 2025–26
- Planning remediation options to close the lagoon and address any residual concerns
Projects in 2026-27
- Complete remediation of the Teslin Lagoon site.
Partners
This project is funded by the Federal Contaminated Sites Action Plan (FCSAP) and delivered in partnership with:
- Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC)
- Teslin Tlingit Council (TTC)
- Government of Yukon
- Environmental consultants, including ERM Consultants Canada Ltd.
Benefits
- Protects the water quality, wildlife habitat, and environment of the region
- Addresses potential long-term risks to human health
- Supports Indigenous-Crown collaboration in environmental stewardship
- Advances the Government of Canada's commitment to responsible management of federal contaminated sites