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kt r Site Background Information Eckert Cold Storage,Manteca,CA February 27,2006 Page 5 of S The average groundwater elevation was approximately 1 11 feet higher on March 17, 2004 than the previous sampling event conducted on December 17, 2003 The groundwater elevation contours estimated with the depth to water measurements indicated the groundwater gradient was variable but overall towards the northwest The groundwater gradient estimated with a three-point construction using wells MW-3, MW-4, and MW-6 was 0 001 ft/ft towards the northwest, and was generally consistent with historic groundwater gradients estimated for the site Condor conducted the second quarter 2004 groundwater monitoring event at the site on June 23, 2004 Groundwater samples were collected and submitted for laboratory analyses from monitoring wells MW4, MW-8, and domestic well DW-1 No separate phase petroleum was noted in the wells, but a moderate petroleum odor was noted in groundwater inspection samples recovered from MW-4 and MW-8 The groundwater samples collected from the monitoring wells and the domestic well were analyzed for BTEX, TPH-G, and selected gasoline oxygenates/additives including MTBE Laboratory analytical results for the June 23, 2004 monitoring event were generally consistent with historical laboratory analytical results The average groundwater elevation was approximately 2 01 feet lower on June 23, 2004 than the previous sampling event conducted on March 17, 2004 The groundwater elevation contours estimated with the depth to water measurements indicated the groundwater gradient was variable but overall towards the northwest The groundwater gradient estimated with a three-point construction using wells MW-3, MW- 4, and MW-6 was 0 002 ft/ft towards the northwest, and was generally consistent with historic groundwater gradients estimated for the site The average groundwater elevation was approximately 2 01 feet lower on June 23, 2004 than the previous sampling event conducted on March 17, 2004 The groundwater elevation contours estimated with the depth to water measurements indicated the groundwater gradient was variable but overall towards the northwest The groundwater gradient estimated with a three-point construction using wells MW-3, MW- 4, and MW-6 was 0 002 ft/ft towards the northwest, and was generally consistent with historic groundwater gradients estimated for the site Condor conducted the third quarter 2004 groundwater monitoring event at the site on September 7, 2004 Groundwater samples were collected and submitted for laboratory analyses from monitoring wells MW-4 and MW-8 No separate phase petroleum was noted in the wells,but a strong petroleum odor was noted in groundwater inspection sample recovered from MW-8 The groundwater samples collected from the two monitoring wells were analyzed for BTEX, TPH-G, and selected gasoline oxygenates/additives including MTBE Laboratory analytical results for the September 7, 2004 monitoring event were generally consistent with historical laboratory analytical results Water levels were collected from all eight of the sites monitoring wells The average groundwater elevation was approximately 1 28 feet lower on September 7, 2004 than the previous sampling event conducted on June 23, 2004 The groundwater gradient estimated with a three-point construction using wells MW-3, MW-4, and MW-6 was approximately 0 001 ft/ft towards the north Historically, the groundwater gradient is vanable,but generally to the northwest Condor conducted the fourth quarter 2004 groundwater monitoring event at the site on December 30, 2004 Groundwater samples were collected and submitted for laboratory analyses from monitoring wells MW-4, MW-5, MW-7, and MW-8 No separate phase petroleum was noted in the wells, but a strong petroleum odor was noted in the groundwater inspection sample recovered from MW-8 The groundwater samples collected from the four monitoring wells were analyzed for BTEX,TPH-G, and selected gasoline oxygenates/additives including MTBE Laboratory analytical results for the December 30, 2004