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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 (SJCPHD/EHD) directed Eckert Cold Storage to conduct a
<br /> site investigation and submit a Problem Assessment Report. In response to the directive from the
<br /> SJCPHD/EHD, WHF, Inc. (WHF) installed three monitor wells identified as MW-1, MW-2, and MW-3
<br /> in January 1995. During initial development of the wells, it was discovered that the well casing of MW-2
<br /> 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 (MW4) was installed at
<br /> the site on March 22, 1995.
<br /> On September 18 and 19, 1997, three additional monitor 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 /> f-the shallow borings was completed as an additional monitor well (MW-8). Additionally, a deep boring
<br /> was advanced to a depth of 56.5 feet bgs to evaluate the vertical extent of contamination in the location of
<br /> the former UST area. Petroleum hydrocarbon constituents were detected in all of the soil samples
<br /> 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 2001 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 /> monitor 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 monitor wells, MW-1,
<br /> 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 monitor wells MW-3 and MW-8. The
<br /> groundwater samples collected from the monitor wells and the domestic well were analyzed for BTEX,
<br /> THP-G, and selected gasoline oxygenates/additives including MTBE by Excelchem Laboratories, Inc. of
<br /> Roseville, California. Laboratory analytical results for the June 26, 2002, monitoring event were generally
<br /> 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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