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' 16 April 2002 i AGE-NC Project No 00-0769 Page 2of6 ' TPH-g, BTEX and 1,2-DCA have been detected at concentrations as high as 230,000 gg/l, 46,000 µg/1 and 3,800 gg/l,respectively,in groundwater samples collected from MW-1,MW-2A,MW-2B, MW-3A and MW-313 The highest concentrations of analytes have been detected in MW-1, the ' lateral and vertical extent of dissolved-phase hydrocarbons has not been defined by the current ground water monitoring network ' In August 2001, six cone penetrometer testing (CPT) borings were advanced at the site Ground water samples were collected from each boring to depths as great as 173 feet bsg Petroleum hydrocarbon-constituents were detected in 27 of the 29 `grab' ground water samples collected ' TPH-g, benzene and 1,2-DCA were detected at concentrations as high as 140,000 micrograms per liter(gg/l), 33,000 µg/l and 2,700 gg/l,respectively Procedures and results of the August 2001 site subsurface investigation were presented in the AGE-prepared Cone Penetrometer Testing Site ' Investigation Report, dated 10 December 2001 ' 3.0. PROCEDURES On 05 March 2002, ground water monitoring was performed at the site Field procedures were performed in accordance with Central Valley Regional Water Quality Control Board(CVRWQCB) and San Joaquin County Environmental Health Department (EHD) guidelines for subsurface investigations of underground storage tank(UST)sites and sampling ground water monitoring wells, respectively 1 3 1 WELL MONITORING AND EVACUATION On 05 March 2002,the depth to ground water was measured from the top of each well casing to the nearest 0 01-foot utilizing a Solinst water level meter Ground water elevations in each well were calculated by subtracting the measured depth to ground water from surveyed casing elevations ' (Table 1) During the March 2002 monitoring event, a two-stage pump was used to purge the deep monitoring ' wells MW-2A and MW-3A of standing water following depth to water measurments,new disposable plastic bailers were used to purge shallow wells MW-1, MW-213 and MW-3B Between 40 and 45 gallons and 7 and 8 gallons of water were removed from the deep wells and the shallow wells, 1 respectively (a minimum of 3 casing-water volumes) Ground water temperature, pH and conductivity were measured at regular intervals during purging using an Oakton water analyzer Field sheets and data from the March 2002 monitoring events are included in Appendix A Purged ' water was stored on-site in labeled, 55-gallon DOT-approved drums Advanced GeoEnviranmentai,Inc 1