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Mr Don Rodgers Project 2613-100.01 <br /> February 13, 1997 <br /> Page 3 <br /> groundwater gradient was 0 002, and the direction of groundwater flow was from northeast to <br /> southeast (see Figure 3) <br /> A groundwater sample was collected from monitoring well MW-IR and was analyzed at Sparger <br /> Technology Laboratories in Rancho Cordova, California. The groundwater sample was analyzed <br /> for TPHG and BTEX using U S Environmental Protection Agency (USEPA) Modified Methods <br /> 8015 and 8020, respectively. In addition, the groundwater sample was analyzed for MTBE using <br /> USEPA Methods 8020 and 8260 Copies of the chain-of-custody records and laboratory analysis <br /> reports are presented in Appendix B <br /> The results of laboratory analyses indicated that dissolved hydrocarbons were present in the monitoring <br /> well. TPHG and benzene were detected at concentrations of 19,000 ppb and 1,700 ppb, respectively <br /> MTBE was detected in the well at a concentration of 370 ppb using USEPA Method 8020 and was <br /> below laboratory detection limits using USEPA Method 8260 Results of laboratory analyses are <br /> presented in Table 1 <br /> CONCLUSIONS <br />. The groundwater flow direction was toward the northeast to southeast and is consistent with general <br /> flow direction observed at the former ARCO Service Station during previous sampling events <br /> Groundwater analytical results are consistent with the previous sampling event <br /> ACTIVITIES PERFORMED DURING THE FOURTH QUARTER <br /> • EMCON performed quarterly groundwater sampling <br /> • EMCON developed the vapor extraction wells VW-1 through VW-4 <br /> ANTICIPATED WORK <br /> • EMCON will continue to perform quarterly groundwater sampling The next samphng <br /> event is scheduled for March 1997 <br /> SAC\N\PJ2\2613\26131000 I AS-97VEb 2 <br />