Healing a First Nation's water body
At a glance
For centuries, the Mi’kmaq community of Pictou Landing First Nation used a tidal estuary in Nova Scotia for refuge, recreation, fishing hunting and gathering. They called it A’se’k, which means “over there” or “the other room.” They relied on this estuary for their well-being. Non-native people call this 156-hectare saltwater habitat “Boat Harbour.”
When the water turned brown
In the mid-1960s, the provincial government built the Boat Harbour Effluent Treatment Facility to create jobs. The facility treated waste from a paper mill and other industries.
The government promised the community they would still have access to their homeland resources. But the facility’s wastewater treatment basin blocked the estuary’s connection to the ocean. Much of the community’s land use was lost, and the estuary filled with brown, foamy, putrid-smelling wastewater. Residents reported respiratory and skin problems and elevated cancer rates as a result.
Fixing what went wrong
Feeling betrayed, Indigenous representatives protested with fishers and conservationists. Some call Pictou Landing Canada’s worst case of environmental racism.
When a pipeline ruptured in 2014, it spilled 47 million litres of toxic wastewater into an Indigenous burial ground on the East River shore. That prompted the government to take needed steps to return A’se’k to a tidal estuary. In 2020, the treatment facility stopped taking in new waste.
One problem stood in the way: one million cubic metres of contaminated sludge and sediment in the water.
Much of this material contains dioxins and furans, which are toxic and carcinogenic at elevated concentrations. Testing also found cadmium, mercury, polycyclic aromatic hydrocarbons, petroleum hydrocarbons and zinc.
Together with the Province of Nova Scotia and the Pictou Landing First Nation, we planned and designed remediation to return the harbour to a tidal estuary and reconnect the community to the land and waters.
First steps: removing and disposing of the sediment
Our biggest challenge was how to remove the sediment safely and cost-effectively without creating a lot of waste or spreading contaminants. Here’s how we approached it:
- Rebuilt trust with the Indigenous community: Generations have been deprived of hundreds of acres of land and the estuary, affecting health and well-being. We engaged Indigenous residents throughout the project so they would understand the challenges. Their firsthand experience and collaboration during investigation, remediation and pilot-scale studies were critical.
- Brought in a wide range of technical expertise: We mobilized 20+ experts with extensive knowledge of remediation options. This wide range of expertise proved essential for our final recommendations.
- Chose the best sediment removal method: We tested several remediation options, including excavation and dewatering (draining water and removing sediment) and dredging (removing from the water directly). The most technically successful, cost-effective option is dredging with Geotubes®. Geotubes® trap and dewater the sediments as they’re removed from the water, leaving more easily disposed-of solids.
- Selected a safe, cost-effective disposal method: Restoring the land to pre-industrial use and transporting waste offsite could cost up to C$1 billion. Onsite disposal is limited by space. We determined disposal in a nearby landfill was the least expensive and risky.
Lessons learned
Our lessons learned can be applied at similar sites:
- Approach problems holistically: It’s not just about moving sediment. We couldn’t use conventional removal methods to access the soft sediments underneath the contaminants. Our wetlands, dredging, geotechnical, biology, engineering and construction specialists determined the safest removal method with minimal disruption to fish or vegetation.
- Find meaningful roles for local people: Given the spiritual significance of A’se’k, it was important to incorporate First Nations’ interests into our work. Experts discussed ways of resolving the sediments during community meetings. Indigenous people shared traditional knowledge about the site and were hired to work on the project. This helped reassure them the work was being done safely and effectively. The skills transferred will help Indigenous-owned enterprises compete for future remediation projects.
- Convene a multidisciplinary team: Our team’s extensive knowledge of treatment technologies informed the process. Their experience reassured stakeholders, especially the First Nation people, that A’se’k can become a vibrant place again.
- Approach options using objective, methodical project delivery: Our project plan guided us to evaluate options in an unbiased, traceable manner. We were open, transparent and honest with stakeholders, comparing each alternative against success criteria.
- Prepare for the unexpected with a cohesive strategy. Unprecedented freezing weather during pilot-scale testing delayed it for four months. In spite of complex regulatory requirements, we completed the project on time and on budget.
- Incorporate community well-being into project success. We conducted a wellness study, the first done for the area. It helped us understand how the community would feel about the remedial solution and how it might help their well-being.