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Quik Stop Markets, Inc. Page A-2 Project No. F7132.32 Well MW-1 was destroyed on October 3, 1990, due to concerns that it may have connected two water bearing units. On April 2, 1991, RESNA replaced the destroyed groundwater monitoring well, MW-1, with two monitoring wells, designated MW-1R and MW-5. MW-lR was designed to monitor the local aquifer and MW-5 to monitor a "perched" aquifer discovered during the installation of MW-1. Analyses of all subsurface and analytical data indicated the presence of two ' aquifers beneath the eastern portion of site. It was found that the local aquifer had no detectable TPHG or BTEX and the perched aquifer contained TPHG and some BTEX components (Exceltech/RESNA, July 1991). 1 At the time of the initial groundwater sampling for MW-1R and MW-5, the San Joaquin County Public Health Services (SJCPHS) required that groundwater samples be collected from all monitoring wells and analyzed for fecal coliform. On April 8, 1991, sampling for this analysis was performed and fecal coliform was only detected in the sample collected from MW-2. It was the decision of SJCPHS that the groundwater samples from this well shall continue to be analyzed for fecal coliform. In subsequent sampling, no fecal coliform has been detected in this well. It is known that a main sewer line was located beneath West Hammer Lane, approximately 30 to 40 feet away from MW-2. Since this is the only well in which any fecal coliform has been detected and it is the well closest to this sewer line, it is likely that this sewer line was the source of the fecal coliform. Such conditions are beyond the control of Quik Stop Markets. The purpose of these . monitoring wells is to aid in the determination of the presence and/or extent of petroleum hydrocarbons in the groundwater. It was the recommendation of RESNA that Quik Stop Markets be permitted to discontinue fecal coliform testing of the groundwater collected from monitoring well MW-2. In a letter to Quik Stop Markets dated December 5, 1991, the SJCPHS reduced the required fecal coliform sampling frequency in monitoring well MW-2 to semi-annual (every other quarter). Since the initial occurrence of fecal coliform in April 1991 no fecal coliform has been detected in this well. Information obtained to date indicates that the gasoline plume extends beyond the station boundary to the east. RESNA and Quik Stop Markets have been attempting to obtain permission to enter the adjacent property to the east. This site is owned by a Taco Bell restaurant and efforts to gain permission to enter this property were not successful. In August 1991, RESNA initiated quarterly pumping of monitoring well MW-5. This pumping was agreed upon with the SJCPHS in August 1991 as a temporary interim remedial activity pending receipt of permission to enter adjacent downgradient properties. When well sampling purge water and equipment rinse water is transported from the site by Exceltrans (a licensed hauler), monitoring well MW-5 is pumped using a vacuum truck with a clean PVC-extension. During the pumping, water in the well is kept at a low level by periodic pumping over a period of about 3 hours. Previous measurements indicate that pumping for 3 hours removes approximately 200 gallons of groundwater. Groundwater samples are obtained prior to and at the completion of pumping. The groundwater samples are collected following the procedures outlined in the RESNA groundwater sampling protocol (Appendix B). The samples are transported to RESNA Environmental Laboratories, a state-certified laboratory located in Fremont, California and analyzed for TPHG and BTEX. The results of these analysis are presented in the quarterly reports.