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former tank excavation. On June 4, 1992 a water sample was collected from the well and <br /> ' analyzed for total petroleum hydrocarbons (TPH as gasoline and diesel) and volatile <br /> aromatics (BTE&X). TPH contamination was detected in the water sample and the San <br /> Joaquin County Public Health Services - Environmental Health Division (PHS/EHD) <br /> required further groundwater assessment. The results of the initial monitoring well <br /> installation and sampling were detailed in a report submitted to the PHS/EHD dated June <br /> ' 26, 1992. <br /> Two additional monitoring wells were installed by GeoAudit on November 12, 1992. One <br /> well (MW-3) was installed south of the warehouse, near the southern boundary of the <br /> property (near the Manna Pro facility). The other monitoring well (MW-2)was installed east <br /> of the former tank excavation. Installation, sampling procedures, and results were described <br /> ' in the Groundwater Monitoring Well installation Report dated January 8, 1993. No soil <br /> contamination was detected in samples from MW-2 or MW-3. <br /> ' On June 17, 1993, two additional monitoring wells were installed on the Cutter Lumber <br /> property to the north of monitoring well MW-1. MW-4 was installed near the southeast <br /> corner of the Cutter Lumber office, north-northeast of monitoring well MW-1; MW-5 was <br /> ' installed at the west edge of the property, northwest of monitoring well MW-1. Installation, <br /> sampling procedures, and results were described in the Groundwater Monitoring Well <br /> Installation and Sampling Report dated June 1993. No soil contamination was detected in <br /> ' samples from MW-4 or MW-5. <br /> 2.5 Groundwater Monitoring <br /> Groundwater monitoring at this site began in June 1992, following installation of MW-1. The <br /> monitoring program was performed on a semi-annual basis through June 1993. Since then, <br /> monitoring has been conducted quarterly. The most recent monitoring is the sixth (6) time <br /> that groundwater data have been collected at the site. - <br /> ' The depth to groundwater is measured in all wells and samples are collected from MW-1, <br /> MW-4, and MW-5 during each event. Wells MW-2 and MW-3 are sampled only annually <br /> ' (in June), because no contamination was detected in these wells when they were installed <br /> in June 1992 and they are believed to be beyond the limits of groundwater contamination. <br /> ' 2.5.1 Groundwater Depth and Gradient <br /> The depth to groundwater at the site rose from approximately 42 feet in November of 1992 <br /> ' to 37 feet in July of 1993, then fell to 44 feet in October of 1993. These fluctuations are due <br /> to seasonal effects and are common at most sites in San Joaquin County. <br /> ' The groundwater gradient at the site has rotated from N 41° W in November of 1992 to N <br /> 19° E in October of 1993. <br /> Cmbywl Ardu Sen+.,fer. <br /> 4W...lift QR-W Pal I.IO <br />