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' SITE BACKGROUND INFORMATION
<br /> ' ECKERT COLD STORAGE
<br /> Manteca, California
<br /> In July 1986, a 500-gallon capacity underground storage tank (UST), identified as TK4, was removed
<br /> from the site Laboratory analyses of soil samples collected from the UST removal area in April 1987
<br /> ' indicated the soil was impacted with petroleum hydrocarbons In February 1988, three remaining USTs
<br /> were removed from the vicinity of the former location of TK4 Laboratory analyses of soil samples
<br /> collected during removal of the three remaining USTs did not identify petroleum impacted soils
<br /> ' As a result of the soil contamination identified in April of 1987, the San Joaquin County Public Health
<br /> Department/Environmental Health Division (SJCPHDIEHD) directed Eckert Cold Storage to conduct a
<br /> site investigation and submit a Problem Assessment Report In response to the directive from the
<br /> ' SJCPHDIEHD, WHF, Inc (WHF) installed three monitoring wells identified as MW-1, MW-2, and MW-
<br /> S in January 1995 During initial development of the wells, it was discovered that the well casing of MW-
<br /> 2 had been damaged during installation of the well, such that bailers and pumps could not be placed down
<br /> the well Because petroleum hydrocarbon contamination was noted in all three borings drilled for MW-1
<br /> through MW-3, WHF elected to use MW-2 for groundwater gradient data collection and install an
<br /> additional well in the down-gradient direction Consequently, an additional well (MW-4) was installed at
<br /> ' the site on March 22, 1995
<br /> On September 18 and 19, 1997, three additional monitoring wells identified as MW-5, MW-6, and MW-7
<br /> ' were installed at the site A sensitive receptor survey for the site was conducted by WHF in 1998 On
<br /> November 2 and 3, 1999, WHF advanced four shallow soil borings to depths ranging from 38 to 41 5 feet
<br /> below ground surface (bgs) Groundwater was reportedly encountered at approximately 23 feet bgs One
<br /> of the shallow borings was completed as an additional monitoring well (MW-8) Additionally, a deep
<br /> ' boring was advanced to a depth of 56 5 feet bgs to evaluate the vertical extent of contamination in the
<br /> location of the former UST area Petroleum hydrocarbon constituents were detected in all of the soil
<br /> samples collected from the deep boring
<br /> WHF conducted quarterly groundwater monitoring activities at the site from April 1995 to December
<br /> 2001 Condor conducted quarterly groundwater monitoring activities at the site on February 27, 2002, and
<br /> ' prepared the First Quarter 2002 Groundwater Monitoring Report, dated April 26, 2002, describing the
<br /> results of work On April 8, 2002, Condor re-surveyed the monitoring wells at the site in accordance with
<br /> CRWQCB directives regarding Electronic Deliverable Format (EDF) for UST sites The new EDF
<br />' monitoring well data was used in the First Quarter 2002 Groundwater Monitoring Report
<br /> Condor conducted the second quarter 2002 groundwater monitoring event at the site on June 26, 2002
<br />' Groundwater samples were collected and submitted for laboratory analyses from monitoring wells, MW-
<br /> 1, MW-3, MW-4, MW-5, MW-6, MW-7, MW-8, and domestic well DW-1 No sheen or separate phase
<br /> petroleum was noted in the groundwater recovered from the wells, however, a strong petroleum odor was
<br /> noted in MW-1 and moderate petroleum odors were noted in monitoring wells MW-3 and MW-8 The
<br /> groundwater samples collected from the monitoring wells and the domestic well were analyzed for
<br /> BTEX, THP-G, and selected gasoline oxygenates/additives including MTBE by Excelchem Laboratories,
<br /> Inc of Roseville, California Laboratory analytical results for the June 26, 2002, monitoring event were
<br />' generally consistent with historical laboratory analytical results
<br /> • The average groundwater elevation was approximately 2 2 feet lower on June 26, 2002 than the previous
<br />' sampling event conducted on February 27, 2002 The groundwater elevation contours estimated with the
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