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1 <br /> i <br /> • <br /> iJuly 23, 2002 RWQCB #390652 <br /> Global ID #T0607700504 <br /> Mr Mike Infurna, Jr <br /> Senior REHS Confirmation #2043107867 ' <br />' <br /> County of San Joaquin <br /> Public Health Services/Environmental Health Division <br />' 304 East Weber Avenue, 3rd Floor <br /> Stockton, CA 95202 <br /> ti <br />' RE Former Thrift Oil Co. Station #172 <br /> TOSCO Station #2705449 <br /> 7647 Pacific Avenue <br /> Stockton, CA 95207 <br /> 2nd Quarter 2002, Status Report <br /> Dear Mr Infurna <br /> Presented herein is the Second Quarter 2002, Status Report prepared for former Thrifty Oil Co <br /> (Thrifty) Station#172 located at 7647 Pacific Avenue, Stockton, California(Figure 1) Presented <br /> in this report are the results of the site monitoring and remediation system operation activities <br /> . conducted during the second quarter of 2002 Thrifty has retained Earth Management Co (EMC) <br /> to conduct quarterly monitoring, sampling, and remediation activities at this site <br /> Groundwater Monitoring <br /> I Depth to groundwater is measured in each monitoring well on a quarterly basis Gauging data <br /> obtained from June 1991 through May 22, 2002 is presented in Table 1. In general, groundwater <br /> occurs under the site at depths ranging from 30 06 feet below ground surface (bgs) in monitoring <br /> I well MW-5 to 34 30 feet bgs in monitoring well MW-7 (Appendix A) A groundwater elevation <br /> contour map based upon May 22, 2002 data is presented as Figure 1 Groundwater flow direction <br /> beneath the site is toward a trough near well MW-7, with a gradient of approximately 0 04 feet/foot ✓ <br /> Quarterly Groundwater Sampling <br /> IAs part of the groundwater monitoring program, groundwater samples were obtained from <br /> monitoring wells MW-3 through MW-11, except MW-8 which was abandoned Groundwater <br /> samples were obtained by EMC on May 22, 2002, and delivered in a chilled state, in an ice chest, <br /> Ifollowing strict Cham-of-Custody procedures to a state certified laboratory These samples were <br /> analyzed for volatile aromatic compounds of benzene, toluene, ethylbenzene, and xylenes (BTEX) <br /> and selected oxygenates (including MTBE) by EPA method 8260B, and total petroleum <br /> hydrocarbons (TPH-g) by EPA method 8015M modified for gasoline Ethanol and methanol were <br /> analyzed by method D285 (Glycols-Alcohols) <br /> I <br />