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• Two, 1,000 gallon gasoline UST's, and associated piping and dispenser pumps have been removed from the property. • The site of the UST's was overexcavated, and over 125 cubic yards of contaminated soil was removed and properly disposed of. The hole was filled with clean material and covered with asphalt. • Three (3) soil borings, three (3) groundwater monitoring wells, and three (3) geoprobe holes have defined the limits of the soil and water plume to the east, south, and west. The plumes are not fully defined to the north, and appear to extend beneath the southeast portion of the office building and warehouse, and into the driveway on the east side of the property - see PLATE II. • As shown on TABLES V & VI, there was a dramatic drop in concentrations of BTEX & TPHg in MW-1 & MW-3 between the April & July, 1998 sampling events. The water table dropped almost one foot between those samplings, and the hydraulic gradient continues to be fairly consistent to the north. This suggests that some natural attenuation is occurring beneath the site. The levels of BTEX & TPHg detected in GP-2 & GP-3 are compatible with other . data collected to date. • Data collected from GP-3 suggests the presence of an aquitard between 17 feet and 23 feet; it appears to exist beneath the entire impacted area. CONCLUSIONS. Based upon all of the data collected to date, we believe this is a "low risk" site, and does not pose any threat to existing potable water supplies in the area. The limits of the plume have been well defined in three directions, and levels of gasoline compounds have decreased dramatically since April. An aquitard appears to limit vertical migration of contamination, and the shallow depth to groundwater everely limits cleanup options. Further work does not appear ia & Associates 1998 \5��?Ec G�c�o RWQCB Gfpirer�//t� ' • � ��.ivy ,� . CFC 6