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Site Background Information
<br /> Eckert Cold Storage,Manteca,CA
<br /> October 14,2003
<br /> Page 3 of 4
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<br /> Condor conducted the fourth quarter 2002 groundwater monitoring event at the site on December 9, 2002.
<br /> Groundwater samples were collected and submitted for laboratory analyses from monitor wells, MW-1,
<br /> MW-3 through MW-8, and domestic well DW-1. No separate phase petroleum was noted in the wells, but
<br /> a strong petroleum odor was noted in groundwater recovered from MW-1 and MW-8; a slight petroleum
<br /> odor was noted in MW-3; and a moderate "earthy" odor was noted in MW-7. A broken sheen was
<br /> observed in the groundwater purged from MW-1.The groundwater samples collected from the monitor
<br /> wells and the domestic well were analyzed for BTEX, TPH-G, and selected gasoline oxygenates/additives
<br /> including MTBE. Laboratory analytical results for the December 9, 2002, monitoring event were
<br /> generally consistent with historical laboratory analytical results.
<br /> The average groundwater elevation was approximately 1.96 feet higher on December 9, 2002, than the
<br /> previous sampling event conducted on September 30, 2002. The groundwater elevation contours
<br /> estimated with the depth to water measurements indicated the groundwater gradient was generally
<br /> towards the west. The groundwater gradient estimated using MW-4, MW-6, and MW-7 was 0.00176
<br /> ft./ft, towards the northwest, and was generally consistent with historical groundwater gradients estimated
<br /> for the site.
<br /> In a letter dated March 7, 2003, Condor proposed that the groundwater monitoring program be reduced to
<br /> include quarterly sampling of MW-4, MW-8, and the domestic well; annual sampling of MW-5 and MW-
<br /> 7; and no further sampling of MW-1, MW-3, and MW-6. In a fax dated March 21, 2003, Mr.Harlin Knoll
<br /> of SJCEHD approved this reduction in sampling.
<br /> • Condor conducted the first quarter 2003 groundwater monitoring event at the site on March 28, 2003.
<br /> Groundwater samples were collected and submitted for laboratory analyses from monitor wells MW-4,
<br /> MW-8, and domestic well DW-1. No separate phase petroleum was noted in the wells, but a moderate
<br /> petroleum odor was noted in groundwater recovered from MW-8. The groundwater samples collected
<br /> from the monitor wells and the domestic well were analyzed for BTEX, TPH-G, and selected gasoline
<br /> oxygenates/additives including MTBE. Laboratory analytical results for the March 28, 2003, monitoring
<br /> event were generally consistent with historical laboratory analytical results.
<br /> The average groundwater elevation was approximately 0.57 feet higher on March 28, 2003, than the
<br /> previous sampling event conducted on December 9, 2002. The groundwater elevation contours estimated
<br /> with the depth to water measurements indicated the groundwater gradient was generally towards the
<br /> northwest. The groundwater gradient estimated using MW-4, MW-6, and MW-7 was 0.0013 ft./ft.
<br /> towards the north, and was generally consistent with historical groundwater gradients estimated for the
<br /> site.
<br /> Condor conducted the second quarter 2003 groundwater monitoring event at the site on June 5, 2003.
<br /> Groundwater samples were collected and submitted for laboratory analyses from monitor wells MW-4,
<br /> MW-8, and domestic well DW-1. No separate phase petroleum was noted in the wells, but a slight
<br /> petroleum odor was noted in groundwater recovered from MW-8. The groundwater samples collected
<br /> from the monitor wells and the domestic well were analyzed for BTEX, TPH-G, and selected gasoline
<br /> oxygenates/addltives including MTBE. Laboratory analytical results for the June 5, 2003, monitoring
<br /> event were generally consistent with historical laboratory analytical results.
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