|
November 5,2001
<br />53636.001
<br />Mr. Peter Ingram
<br />City of Redwood City
<br />Page 2
<br />
<br />in groundwater beneath the site area, the Alameda County Health Care Services Agency (ACHCSA)
<br />and SFRWQCB required that soil and groundwater investigations also be conducted at other nearby
<br />properties suspected of being potential sources of the HVOCs, such as Roy's Cleaners located on the
<br />comer of Harrison Avenue and ECR across from the former Davies parcel, and a segment of the City's
<br />sanitary sewer line beneath ECR adjacent to the Davies parcel. Mr. Terry McManus, now with Harding
<br />ESE, assisted the City with discussions between Safeway and SFRWQCB staff, and with assessment of
<br />the sanitary sewer as a potential source of the HVOCs in groundwater.
<br />
<br />Former Davies Parcel
<br />
<br />From the early 1940s to the mid-1990s, the former Davies parcel was used by Davies Chevrolet as an
<br />automobile dealership and maintenance facility. The business discharged wastewater to the City's
<br />sanitary sewer via a lateral connection. Today, the parcel is occupied by an Old Navy retail clothing
<br />shop, and a parking lot.
<br />
<br />Soil and groundwater investigations were conducted for Safeway at the Davies parcel from 1993
<br />through 1995 by Einarson Geoscience, Inc. (EFW), currently known as Conor Pacific/EFW. Results of
<br />EFW's investigations2'3 indicated that releases of petroleum hydrocarbons and several HVOCs,
<br />primarily tetrachloroethene (PCE), trichloroethene (TCE), and/or cis-l,2-dichloroethene (cis-DCE), had
<br />occurred to soil and/or groundwater beneath the Davies parcel. The highest concentrations of PCE,
<br />TCE, and cis-DCE detected in groundwater collected at this parcel were 18,000 micrograms per liter
<br />(ug/L), 760 ug/L, and 740 ug/L, respectively, in a groundwater sample collected from piezometer D-2
<br />(located adjacent to ECR).
<br />
<br />All piezometers located at the former Davies parcel were decommissioned between August 1995, during
<br />the removal of petroleum hydrocarbon-contaminated soil, and May 1997. During the last groundwater
<br />monitoring event conducted at the former Davies parcel in 1997, the highest concentrations of PCE,
<br />TCE, and cis-DCE detected were 1,300 ug/L, 72 ug/L, and 270 ug/L, respectively, in piezometer D-25.
<br />
<br />Former Ramey and Greer/SPRR Parcels
<br />
<br />EFW also conducted soil and groundwater investigations of the former Ramey and Greer/SPRR
<br />properties prior to redevelopment of Sequoia Station, and has performed quarterly groundwater
<br />monitoring at these two areas since 1994 and 1993, respectively. The Ramey parcel was previously
<br />occupied by Ritz Cleaners. Today the parcel is occupied by retail shops and parking areas of the
<br />Sequoia Station shopping center. The highest PCE, TCE, and cis-DCE concentrations historically
<br />detected in groundwater collected at this parcel were 1,400, 300, and 1,200 ug/L, respectively, found in
<br />well MW~6 (August 1993). SCI indicated in their Work Plan that these concentrations have fluctuated
<br />over the last 5 years, but have generally decreased with time. The highest concentrations detected
<br />
<br />2 Einarson Geoscience, Inc., Report of Site Assessment, Davies Proper~y, September 1994.
<br />
<br />3 Einarson Geoscience, Inc., Report of Site Investigation, Davies Property, March 1995.
<br />
<br /> ?ff
<br /> Harding ESE
<br /> A MACTEC
<br />
<br />
<br />
|