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' Page 2 Mr Michael Infurna Jr,Senior REHS February 8,2001 UST Related Activities A 1,000-gallon gasoline UST located beneath the sidewalk along South Center Street, an associated fuel dispenser located within the property building, and the portion of product piping from the UST to the building were removed in December 1990 The remaining product piping, from the edge of the building to the former dispenser, was properly abandoned on April 17, 1998 On April 16, 1998,Philip drove two 1-inch diameter Geoprobe-type probeholes beneath the former UST to collect soil and groundwater samples for laboratory analysis Analytical results, summarized in Philip's June 2, 1998 Preliminary ' Subsurface Site Investigation Results and Product Piping Abandonment Completion, indicated potential benzene,toluene, ethylbenzene, and xylenes (BTEX) impact to subsurface soil and groundwater Soil and groundwater samples collected at this time did not contain detectable oxygenate compounds In July 1999, Ground Zero Analysis, Inc (GZA) of Escalon, California, performed a subsequent subsurface investigation GZA drilled three soil borings, completed them as groundwater monitoring wells (labeled MW-1 through MW-3), and collected soil and groundwater samples for laboratory analysis GZA's investigation, summarized in their July 28, 1999 Groundwater Monitoring Well Installation Report, detected BTEX and total petroleum hydrocarbon as gasoline (TPHg) impact in soil and groundwater samples collected at the MW-2 �I location(see Figure 2) Samples collected from MW-1 and MW-2,placed in upgradient positions relative to the former UST, did not contain detectable petroleum hydrocarbons The San Joaquin County Environmental Health Division directed that several quarters of groundwater monitoring be performed to assess evolving conditions Philip understands that results from these monitoring events will be used by San Joaquin County_to consider whether future cleanup actions will be required ' First Quarter 2001 Groundwater Monitoring On January 16, 2001, Kleinfelder(under Philip's direction) collected groundwater samples from the three site monitoring wells Prior to sampling, Kleinfelder's geologist measured groundwater levels within the wells with an electronic well sounder, checked for potential free phase petroleum product, and then purged a • minimum of three well volumes from each well with clean, disposable bailers Free phase petroleum product was not observed in any of the wells Temperature,