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r <br /> 7-Eleven/Stockton 12 <br /> ? y,, October 1988 <br /> During this reporting period, the local groundwater-gradient <br /> direction has shifted from a southeasterly to a more easterly <br /> direction. The hydraulic gradient has increased from <br /> approximately 0.18 percent in April to 0.28 percent in September, <br /> 1988. <br /> Free product was detected in MW-1 (0.01 feet) and MW-3 (0.02 <br /> feet) on April 6, 1988. Free product has not been observed in <br /> MW-1 on any subsequent monitoring events. The groundwater table <br /> fell below the bottom of MW-3 after April 6, 1988, therefore, no <br /> additional monitoring data is available for this well. small <br /> amounts of free product were detected in MW--4 throughout this <br /> reporting period until the groundwater table dropped below the <br /> - bottom of the well after the August 23, 1988 monitoring event. <br /> The maximum product accumulation recorded in the well was on June <br /> Y 1, 1988 when 0.13 feet of product was detected (Table 1 in <br /> Appendix I) . <br /> �. GROUNDWATER SAMPLING AND ANALYSES <br /> Groundwater monitoring wells and nearby domestic wells were <br /> sampled on a regular, basis to detect changes in hydrocarbon <br /> concentrations and to document the areal extent of the contami- <br /> nant plume. The samples were collected in accordance with GTI's <br /> SOP's 9, 10, 11, and 12 (Appendix II) . Each sample was analyzed <br /> for benzene, toluene, ethylbenzene, xylenes (BTEX) and total <br /> petroleum hydrocarbons (TPH)-as-gasoline by modified U.S. <br /> Environmental Protection Agency (EPA) Methods 5030/602/8020/8015. <br /> The sampling intervals during this pariod for the wells on and <br /> near the site, were as follows: <br /> GROUNDWATER <br /> r. 1 <br />