Project:
Former Electronics Manufacturing Facility
Bottom Line: Investigating 170+ acres, spanning two cities and an unincorporated county area, and teaming with many consultants and regulatory agencies.
Summary of Project
The 9-acre site formerly contained a facility that manufactured printed circuit boards for more than 30 years, from about 1955 to 1989. Various chemicals were used during its historical operations, including chlorinated solvents from about 1961 to the late 1980’s. In the mid-1980’s, the EPA placed the site in its Superfund program because VOCs were found in several water supply wells. Numerous site studies showed the presence of chlorinated hydrocarbons and metals in the soil and groundwater. From 2012 to 2014, Orion completed the following:
- Prepared a Remedial Design Investigation (RDI) work plan with detailed data quality objectives in coordination with the EPA; the RDI work plan included a quality assurance project plan, field sampling plan, and well installation plan
- Sampled 30 existing vapor monitoring points and SVE wells to evaluate soil vapor contaminants and concentrations and the potential for vapor intrusion
- Installed and sampled 21 triple-nested temporary vapor monitoring points (63 monitoring points) to collect additional soil vapor data needed to fill data gaps or deficiencies
- Drilled 97 soil borings ranging from 57 to 400 feet bgs (over 13,600 linear feet) and performed the tasks below
- Collected over 260 vadose zone soil samples at select locations and depths to evaluate potential vadose zone soil impacts and/or to evaluate physical properties
- Collected over 70 saturated soil samples at select locations and depths for treatability evaluation and/or to evaluate physical properties
- Collected over 550 depth-discrete grab groundwater samples at boring locations to evaluate the nature and extent of groundwater impacts and/or evaluate the potential for vapor intrusion
- Performed visual borehole logging of continuous soil cores using the Unified Soil Classification System to evaluate lithology
- Identified geologic marker beds by visual inspection and assessment by an expert registered geologist
- Performed tests of soil physical parameters on 83 soil samples (68 saturated and 15 vadose zone)
- Prepared data packages for each boring that summarized lithology and grab groundwater analytical data, and proposed well screens
- Installed 90 groundwater monitoring wells ranging from 54 to 280 feet bgs (over 10,500 linear feet), with well clusters screened at multiple depths in consultation with the EPA
- Performed short-duration well yield tests in coordination with well development activities on 24 new wells to obtain well yield information and hydraulic properties of the aquifer
- Provided support for vapor intrusion pathway sampling (shallow groundwater, indoor air, sub-slab, and soil gas) in the immediate vicinity and downgradient of the site
- Evaluated data collected and prepared an RDI report.