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Project 113-13 December 27,1995 Page 2 A fourth monitoring well was installed by Parker Environmental Services at the site on September 6, 1991. Soil samples analyzed from the boring were all ND for TPH-g and BTEX. Groundwater samples obtained on September 11, 1991 from all four monitoring wells were also ND for TPH-g and BTEX. Depth to groundwater was 28 to 29 feet BGS. An aquifer pump test was done by Parker Environmental Services at the site October 15-16, 1991, and it showed that all four monitoring wells are in the same aquifer. Quarterly monitoring was performed by Parker Environmental Services during 1993 In March, 1993, during the first quarter of monitoring, xylene was measured at 1.2, 1.1, and 0 96 ppb in three of the wells (MW-1, MW-2, and MW-3). Toluene was present (1.2 ppb) in MW-4 All wells were ND for both TPH-g and BTEX in July, September, and December, 1993. II. Current Activities Groundwater samples were obtained on April 22, 1994 Prior to sampling, groundwater elevation measurements were obtained with an electronic water level meter. Results are presented in the table below Table 1 Cheapen #76 890 North Main Street, Manteca, California Groundwater Measurement Results* Measured on April 22, 1994 MW-1 MW-2 MW-3 MW-4 Well Elevation 33.12 33.22 3355 33.66 Depth to GW -23.01 -2293 23.32 -2359 GW Elevation 10.11 10-29 1023 10.07 * elevation above mean sea level, in feet Shallow groundwater measurements indicate the water table is approximately 0.3 feet lower than measurements taken in December, 1993. As shown on the attached groundwater flow direction drawing, the flow direction is toward the southwest, with a gradient of about 0 0045 (4.5 feet per thousand feet), similar to the December, 1993, measurements Parker Environmental Services 190 East 7th Street Pittsburg CA 94565-6116 Phone (510) 439-1024 Fax (510) 439-2566