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r r5 r File No 2070 2 22 June 1993 Page 1 r ' 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 two 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 by Tilford and Hall in 1987 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 Health Department 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 2 0 Groundwater Monitoi in f ' The groundwater elevation% for monitoring wells MW-1, MW-2, MW-3, MW-4, MW-6 and MW-8 were measured and recorded on 7 April 1993 Monitoring wells 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 first quarter 1993 Table I presents the groundwater elevation measurements The groundwater flow direction and gradient is discussed in Section 4 0 1 3 0 Groundwater Sampling Sampling of the groundwater monitoring wells was conducted on 7 April 1993 Due to low groundwater levels, only wells MW-1, MW-6 and MW-8 contained %uthtient 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 rcmovc,d from the well %o that the true formational groundwater could be sampled A total of 25 gallons of groundwater were purged tram monitoring well MW-1 Due to the limited quantity of groundwater in monitoring wells MW-6 and MW-8, temperature, ' conductivity and pH readings were not obtained for the%e wells Both wells were purged of approximately 2 to 3 gallons of groundwater until depleted, allowing eai-h well to recharge with formational water The purged groundwater extracted from all three wells was containerized in a 55- gallon drum and stored on the site ANDERSON CONSULTING ' GROUP