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STATUS OF ACTIVITIES AT THE SITE A Problem Assessment Report (PAR) for the site was )Issued on 19 December 1991. 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 to determine the extent of soil and groundwater contamination Additionally, a summary of soil remediation activities was also included in the PAR Remediation of groundwater contamination at the site has not yet been conducted, but is proposed Until a groundwater treatment system is on-line, the San Joaquin County Environmental 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. GROUNDWATER SAMPLING Sampling of the Rainbo Bakery groundwater monitoring wells was conducted on 19 August 1992. Due to recent drought conditions, only wells MVv-i and MW-8 contained sufficient water to allow samples to be collected However, enough water was present in well MW-6 to allow a water elevation reading to be obtained for this well Consequently, static groundwater elevations for wells MW-1, MW-6 and MW-8 were first measured and recorded The elevations were used to calculate the site specific groundwater gradient Following collection of the initial data, monitoring wells MW-1 and MW-8 were purged using a teflon bailer The temperature, conductivity and pH of the groundwater in well MW-1 was measured and recorded 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 tested Due to the limited quantity of groundwater in well MW-8, temperature, conductivity and pH readings were not obtained for this well MW-8 was purged until depleted of groundwater and allowed to recharge with fresh formational water before sampling The groundwater extracted during purging of both wells was containerized in a 55-gallon drum and stored on the site Following completion of the well purging, the wells were allowed to recharge to 85% of their original groundwater level Upon adequate recharge, each of the wells was sampled via a sterile, discrete, disposable bailer The groundwater samples were placed in sterile containers, stored on ice and transported to a State of California certified analytical laboratory Laboratory analyses were conducted for total petroleum hydrocarbons (method 8015 modified/purge and trap), aromatic volatile organics (EPA method 602) and total lead (EPA method 6010) FIELD DATA AND SITE DETERMINATIONS The site-specific groundwater gradient for August 1992 was calculated based on the static groundwater elevations measured in monitoring wells MW-1, MW-6 and MW-8 Based on the measurements, the groundwater gradient for April 1992 was calculated to be toward the east-northeast (see Figure 2) Whale obtaining the groundwater samples, particular attention was paid to whether any noticeable petroleum hydrocarbon odor, discoloration or floating product was evident in the wells. The following was noted during our sampling • Monitoring well MW-1 had a strong petroleum hydrocarbon odor. No floating product or discoloration was noted ANDERSON \, CONSULTING GROUP r