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File No 2070-2 23 March 1494 Page 1 10 Status of Site Activities ' A Problem Assessment Report (PAR) for the site was issued on 19 December 1991 by Anderson Consulting Group (ACG) The PAR summarized activities conducted at the site since the discovery in December 1986 of the release of petroleum hydrocarbons from several underground storage tanks ' Included in the PAR was a summary of investigations, conducted by Environmental Sciences and Engineering (ESE) and ACG, to determine the extent of soil and groundwater contamination Additionally, a summary of soil remediation activities conducted in 1987 by remediation contractors ' Tilford and Hall was also included Remediation of petroleum-impacted groundwater at the site has not been conducted,but is proposed ' Until a groundwater treatment system is on-line, the San Joaquin County Environmental Health Division has requested that quarterly groundwater monitoring be conducted in accordance with the State of California Regional Water Quality Control Board's Underground Storage Tank Regulations ' Burlington Environmental Inc of Columbia, Illinois, the managing consultant for the project, submitted a workplan to the San Joaquin County Environmental Health Division in January 1994 for the installation of additional groundwater monitoring wells at the site The workplan was approved ' by the county in February 1994 The wells were installed between 15 and 18 March 1994 2 0 Groundwater Monitoring The groundwater elevations for monitoring wells MW-1, MW-2, MW-3, MW-6 and MW-8 were measured and recorded on 29 December 1993 Monitoring wells MW-4, MW-5 and MW-7 were dry ' at the time of our monitoring The elevations were used to calculate the local groundwater flow direction and gradient for the fourth ' quarter 1993 Table I presents the groundwater elevation measurements The groundwater flow direction and gradient are discussed in Section 4 0 ' 3 0 Groundwater Sam lin Sampling of the groundwater monitoring wells was conducted on 29 December 1993 Due to low ' groundwater levels, only wells MW-1, MW-6 and MW-8 contained sufficient water to allow samples to be collected Prior to sampling, the monitoring wells were purged of well casing water For monitoring well MW-1, ' the temperature, conductivity and pH of the groundwater was measured and recorded in five gallon intervals during purging This data was used as an aid in determining when an adequate volume of water had been removed from the well so that the true formational groundwater could be sampled ' A total of 25 gallons of groundwater was purged from monitoring well MW-1 1 ANDERSON CVVVy CONSULTING ' GROUP