Phase II ESA, Remedial Investigation/Feasibility Study, Remediation Management
Anderson Geological, Inc. (AGI) completed the environmental site characterization, assessment, remediation design and remediation management of a 150-acre residential development in Salem, Oregon. The site was being prepared for a 700-unit residential development when elevated concentrations of the pesticide dieldrin were discovered in the soil. The concentrations of dieldrin exceeded risk-based cleanup levels for residential receptors over approximately half of the site (152,000 cubic yards).
AGI characterized the lateral extent and depth of the impacted soils and developed a work plan for their removal. Various remedial options were considered, including in-situ biological treatment, removal and landfilling, and removal & re-use. It was decided that the impacted soils would be excavated and re-used at another property eight miles from the North Star site which was the site of an active farm. The re-use of the soils was approved by Oregon DEQ under a Solid Waste Permit Exemption.
AGI developed a dust control and air monitoring plan to be implemented at both the excavation and disposal areas.
The first phase of the project was begun late in the construction season and involved the removal of 30,000 cubic yards of the dieldrin-contaminated soil. The soil was placed in a temporary stockpile on site until the following season, when it would be transferred to the final disposal site.
AGI closely monitored the soil removal and air sampling to assure compliance with the remediation work plan and to document airborne concentrations of dieldrin in work areas and at property boundaries where public exposure could occur. The owner/contractor completed the work without incident and the air monitoring showed no unacceptable dieldrin exposure to the contractor’s workers or to the public. AGI sampled the soil from the excavated areas to document that cleanup levels had been achieved.