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Following the December 1998 quarterly sampling event, AGS requested that the ground water monitoring program be modified to include the sampling of monitoring wells MW- IA and MW-6 only. The request was approved by the San Joaquin Public Health Services in a letter dated February 9, 1999. There are currently five ground water monitoring wells installed at the site. In the Quarterly Ground Water Monitoring Report and Case Closure Request dated September 7, 1999, American Geological Services, Inc requested that "No Further Action Status" be granted the site. The San Joaquin Public Health Services concurred with the recommendation. The Regional Board, in a letter dated February 7, 2000 denied the closure request based on the belief that the South Well did not have a sanitary seal and ' therefore was not protective of domestic water supplies. In March 2004, a new water supply well was installed to the south of the remedial excavation area. The South Well was taken out of service and a downhole video log was made of the well. The results of the video logging confirmed that the steel casing was in poor condition, and that abandonment was warranted. The South Well was abandoned in ' May 2004 in accordance with San Joaquin County and California water well standards. A final round of ground water samples was collected from the remaining five ground ' water monitoring wells on March 24, 2004, and from the north supply well on May 27, 2004. This report presents the analytical data obtained from the two sampling events, and based on those results, requests that "No Further Action Required" status be granted this site. r1.3 Geology The subsurface geology of the site was determined by logging soil samples collected at 1 various intervals during the initial and supplemental site investigations, and the remedial soil excavation. ' Dark brown silty clay dominates the stratigraphy from within one foot of the surface to the bottom of the borings. In general, fine sand was found within the silty clay unit near ' the bottom of the borings at an approximate depth of 20 feet bgs. The moisture content increased with depth and reached saturation between 12 and 16 feet bgs. During the remedial excavation a highly plastic brown clay laver was encountered at a depth of approximately 18 feet bgs. ' I.4 Hydrology Groundwater at the site is contained in a semi-confined or unconfined aquifer typically 10 to 15 feet bgs. However, ground water was measured at an approximate depth of 8 feet • bgs during the spring of 1998. Historically, groundwater at the site demonstrates a shallow gradient that slopes to the northwest. American Geological Sen ice, Inc. CA95DE-029 5