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l <br /> Project 113-13 <br /> April 26, 1995 <br /> Page 2 <br /> A fourth monitoring well (MW-4) was installed by Parker Environmental Services <br /> at the site on September 6, 1991. Soil samples from the boring analyzed ND for TPH- <br /> g and BTEX. Groundwater samples obtained on September 11, 1991 from all four <br /> monitoring wells were also ND for TPH-g and BTEX. Depth to groundwater was 28 <br /> to 29 feet BGS <br /> A pump discharge test was done by Parker Environmental Services at the site <br /> October 15-16, 1991 The drawdown between wells indicated that all four monitoring <br /> wells are probably in the same aquifer. <br /> Quarterly monitoring was performed by Parker Environmental Services during 1993 <br /> In March, 1993, during the first quarter of morutonng, xylenes were measured at 12, <br /> 1.1, and 0.96 ppb in three of the wells (MW-1, MW-2, and MW-3). Toluene was <br /> present (1.2 ppb) in MW-4. All 4 wells were ND for 1,2-dibromoethane (ethylene <br /> drbromide) and for lead. <br /> All wells were ND for both TPH-g and BTEX in July, September, and December, <br /> 1993, and in April and July, 1994 Groundwater levels ranged from about 21 feet BGS <br /> to about 28 feet BGS over that period Morutormg was not performed in October, <br /> 1994, because of the low water table. <br /> Morutoring resumed in January, 1995. Wells MW-1, MW-3 and MW-4 were found <br /> to be free of the chemicals of interest at or above the analytical method detection <br /> limits MW-2 contained 1 3 ppb benzene, 0 91 ppb toluene, 0 79 ppb xylenes, and was <br /> ND for TPH as gasoline and ethylbenzene Groundwater levels had risen back up to <br /> about 22 feet BGS <br /> IL Current Activities <br /> Groundwater samples were obtained on April 18, 1995 Prior to sampling, <br /> groundwater elevation measurements were obtained with an electronic water level <br /> meter Results are presented in the table below <br /> Table 1 <br /> Cheapen #76, 890 North Main Street, Manteca, California <br /> Groundwater Measurement Results' <br /> Measured on April 18, 1995 <br /> MW-1 MW-2 MW-3 MW-4 <br /> Well Elevation 3312 33.22 33.55 3366 <br /> Depth to GW 2088 20.72 2115 2148 <br /> GW Elevation 1224 1250 1240 12.18 <br /> * elevation above mean sea level, In feet <br /> Parker Environmental Services 190 East 7th Street Pittsburg CA 94565-6116 <br /> Phone (510) 439-1024 Fax (510) 439-2566 <br />