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�&oTOR,5 - EuPrUi PrTQrj EXECUTIVE SUMMARY Upgradient Environmental Consultants visited the Valley Motors deaslership on December 4, 1996 ✓ to perform the 4th and final groundwater monitoring event of 1996 The depth to groundwater was measured in all three monitoring wells and approximately 20 gallons of water were pumped from each well to purge the standing water Thereafter, groundwater samples were collected with disposable Teflon bailers and poured into 40-m1 vials and 1-liter amber bottles The sample containers were labelled and placed into an ice chest and transported to Excelchem in Roseville The samples were analyzed for total petroleum hydrocarbons in the gasoline and diesel ranges using EPA method 602, for BTEX using EPA method 8020, and for halogenated hydrocarbons using EPA method 624 Gasoline and diesel were detected in the two wells nearest the former UST cavity, as were all BTEX compounds Bezene, toluene, and ethylbenzene were also reported in the most downgradient well Several halogenated hydrocarbons were detected in the two wells nearest the former UST cavity, some of these compounds had not been previously detected at this site Groundwater gradient data indicate that the direction of flow and slope of the static water surface are essentially unchanged since the last monitoring event in July 1996 Flow is to the east-northeast ✓ at 0 0027 ft/ft Based on the limited groundwater data collected to date at this site, it appears that two plumes of contaminants are dissolved in the groundwater beneath this site, and both have migrated eastward since July As a result, the gasoline plume has now reached the most downgradient well, which is approximately 100 feet downgradient of the leak point In addition,halocarbon concentrations have increased, indicating that the solvent plume is worsening and migrating from an off-site source to the west 1