Fond Du Lac Environmental Remediation

An environmental consultant has identified ten plumes of petroleum hydrocarbon impacts on seven sites in the community of Fond du Lac. Impacts in soil and groundwater exceed calculated site specific guidelines that use a scientific approach to evaluate against human and ecological risk. The consultant has proposed to carry out a remedial action plan which includes partially excavating and landfarming impacts where possible and using anaerobic bioremediation to treat the rest of the impacts in place. Excavation and landfarming will account for approx. 5000m3 of impacts and will utilize the formerly established landfarm area north of the community. Anaerobic bioremediation will account for approx. 19,000m3 and will use fertilizer amendment applied within and upstream of impacts. Permeable reactive barriers containing carbon sources will be placed downstream to protect the lake and other receptors from nutrients in the amendments. The estimated timeline to achieve remedial objectives is 5 field seasons, with completion in fall of 2025.

Remedial Action Plan for approx. 25,000m3 of petroleum hydrocarbon contaminated soils/groundwater
- Remedial Excavation: excavate impacted soils using local equipment, haul to landfarm, replace with clean backfill and clean overburden. Excavations occur where impacts are accessible considering subsurface conditions, structures/buildings, and underground utilities. Backfill from local source. Clean overburden will be temporarily stockpiled and returned to the upper layers of excavated area.
- Anaerobic Bioremediation: treat soils that can't be reached/accessed through excavation. Nutrient amendment will be installed in trenches or surficially to promote anaerobic bioremediation of impacts.
- Permeable Reactive Barrier: PRB will be installed downstream of any plumes adjacent to a waterbody (Lake Athabasca, Meech Lake). PRB will consist of a carbon source that will biodegrade the applied nutrients.
- Monitoring and sampling: Groundwater across community will be monitored and sampled twice per year to observe trends. Locations where soil impacts have been observed will be resampled once it is believed remediation has reached its target concentration. Extents of excavations will be sampled to determined if further excavation or treatment is required in each direction.