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�/ tirl PHS/EHD requested further investigation to delineate the extent of soil contamination and determine whether groundwater had been impacted, and Upgradient drilled SP-10 and SP-11 adjacent to SP-8 in December 1995 and January 1996. Soil samples were collected at greater depths, and groundwater was sampled (Figure 3). SP-10 was drilled to 15 feet and sampled at 8, 9, and 10 feet. SP-1I was drilled to 9 feet and sampled at 8 and 9 feet (Figure 4). Very low concentrations of dkscwere detected in SP-10; no contaminants were detected in SP-11. However, the laboratory reported that the pesticide heptachlor epoxide was detected at a concentration of 0.40 ugll(parts per billion)in the water sample from SP-11. Due to the high turbidity of the sample, however, this result was suspect. Therefore, SP-12 was drilled close to SP-11 in April, 1996 and groundwater sampling was repeated.This sample was less turbid and was filtered prior to analysis in order to remove suspended sediment. a tachlor a oxide was not detected. Therefore, at the previous request of Ms. Wendy Wyels of the Central Valley Regional Water Quality Control Board, Upgradient recommended that the area around SP-8 be excavated to a depth of 7 feet to remove the pesticide contamination in the soil above that depth. 2.0 EXCAVATION PROCEDURES Soil excavation was performed by Stokely Construction on June 15, 1996, under the supervision of Upgradient Environmental and Hoblitzell & Associates. The location of boring SP-8 was determined by measuring from various fixed landmarks (trees, etc.), and the turf was removed from an area measuring approximately 6 feet square around the boring (Figure 3). Stokely used a backhoe to remove the soil and load it into a dump truck. At least three of the four clustered borings(SP-8, SP-10, SP-11, and SP-12) were uncovered during excavation, evidenced by either an open or grouted borehole. The area was excavated to a depth of 80 inches (6 feet 8 inches), and a percussion sampler was then used to collect soil sample SP-13 from the base of the excavation and. sample SP-14 from the north sidewall of the excavation at a depth of 76 inches. Both samples were collected in two 2 x 3-inch brass tubes, labelled SP-13 A, B and SP-14 A, B. One sample was also collected from the excavated soil before the disposal truck departed. The samples were transported to Seqouia Analytical for pesticide analysis. 3.0 SOIL DISPOSAL Based on the laboratory results from boring SP-8, BFI had previously agreed to accept the soil as a non-hazardous waste. Therefore, when excavation was complete, Hoblitzell & Associates transported 5.67 tons(one truck load)under non-hazardous manifest to Altamont Landfill. A copy of the landfill's load receipt is attached. 4.0 LABORATORY RESULTS Tables 1 and 2 summarize all of the laboratory analyses that have been performed at this site. The laboratory report for the excavation samples is attached to this report. 2