Remedial Action Report Construction Phase

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3.0 PREVIOUS INVESTIGATIONS AND REMEDIAL ACTIONS 3.1 Environmental Site Assessments Phase I Environmental Site Assessments (ESAs) have been completed on various portions of the subject property (Bergeson-Boese 1994, Century West 1996a, 1996b, 1996c, 1997a). The purpose of the ESAs was to assess the environmental conditions of the subject properties by examining the site and by reviewing reasonably ascertainable documents and verbal information. Information included in the ESAs indicates that the subject property was developed prior to 1884 and primarily used for commercial purposes from at least 1926. Former commercial uses of the property include auto fueling, auto repair, auto storage, and battery repair activities. Former subsurface structures on the property include lift hoists, basement boilers, drywells, sumps, and several USTs used to store fuels and used oil. Figure 2 is a historical site plan showing the location of former buildings and structures on the subject property. 3.2 Pre-Construction Site Investigation and Remedial Actions Beri Building UST In 1989, a heating oil UST was decommissioned in the alley along the western side of the Beri Building (Figure 2). After investigation and remedial actions conducted between 1990 and 1992 by Marion County's consultant, the DEQ granted site closure in a letter to Marion County dated August 27, 1992 (Century West 1997a). Former Chevron Propertv From 1940 through 1985, Standard Oil and Chevron operated service stations in the southeast corner of the Courthouse Square property (Figure 2). Chevron initiated site investigations and remedial actions at the former service station site in 1989 to address petroleum-impacted soil and groundwater resulting from leaking USTs (GeoEngineers 1991, Pacific Environmental 1993, 1994, 1997). A total of eleven monitoring wells were installed during the investigation. Chevron's remedial actions included excavation and disposal of petroleum-impacted soil, in-situ soil vapor extraction, and air sparging. The remedial efforts reduced concentrations of contaminants in soil and groundwater. However, the presence of the adjacent Lui Building limited access for further removal of contaminated soil. Although Marion County purchased the property in 1994, Chevron continued remedial actions through 1997. Overall Site Investigation In August 1997, Marion County retained Century West to complete a subsurface investigation on the Courthouse Square block (Century West 1997b). The scope of work for the investigation was based on the recommendations from the ESAs. The purpose of the investigation ~vas to evaluate soil Construction Phase - Remedial Actions - 3- 4080600127 Courthouse Square November 9, 1999