PAH-Contaminated Sediment Remediation: An Overview of a Proposed Large Scale Clean-up in a Freshwater Harbour

Randle Reef is an area of severely contaminated sediment located in Hamilton Harbour at the western end of Lake Ontario in Canada. The Randle Reef Sediment Remediation Project work area consists of approximately 60 ha of the harbour bottom that are severely contaminated with polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Total PAH concentrations at the Randle Reef site are as high as 73 755 mg/kg, with an average site concentration of 5000 mg/kg. The Randle Reef Sediment Remediation Project involves the construction of an engineered containment facility (ECF) on top of a portion of the most contaminated sediment. The remaining contaminated sediment will be hydraulically dredged, placed within the ECF, and sealed beneath a cap. Residual contaminated sediment and undredged areas of lesser contamination will be covered over by a thin layer cap. Following completion of the project, the Hamilton Port Authority will assume ownership of the containment facility and monitor, maintain, and develop the site as port facilities. This is a critical project that will lead to the restoration and eventual delisting of Hamilton Harbour as an area of concern in the Great Lakes.