This project was undertaken to address metals contamination (arsenic, lead, and manganese) in soils in residential yards in central Montana. The presence of residual metals is believed to be associated with historic ore processing performed in the area.
Trihydro’s scope of work included assessment, reclamation design, and reclamation construction to limit or eliminate human exposure to arsenic, lead, and manganese contamination above residential action levels at three residential properties. The extent of excavation required for reclamation was estimated based on the results of soils investigations and confirmed in the field through screening with an x-ray fluorescence (XRF) analyzer.
During reclamation, approximately 2,032 tons of metals-impacted soils were characterized, removed from the properties, and properly disposed of at the county landfill. Impacted soils were replaced with clean cover soil and surface features were restored. Post-excavation restoration included planting new trees, placing new sod, importing clean gravel for driveways, and reconstructing fences and various landscaping features including planters, decorative rock walls, patios, and decks. Salvaged materials were used where possible in the reconstruction.
The proximity of this project to a city and state park meant that public communication was a key component of this project’s success. The project team was conscious of the impacts of activities on adjacent landowners and motorists on the adjacent county road, and a traffic control plan was developed that enabled minimal delays to the public.